Migration induction of contact inhibited C3H 10T1/2 cells by protein kinase C (PKC) dependent process.

Treatment of confluent contact inhibited 10T1/2 cells with TPA or OAG induced a dramatic increase of the number of migrating cells, on cover slides inserted into culture dishes. When cover slides were coated with collagen IV or fibronectin, there was a similar increase of the number of migrating cells. RT PCR showed the presence of alpha PKC gene transcripts and the lack of beta and gamma PKC. Western blot analysis showed translocation of 80 kD alpha PKC to membranous fraction following brief treatment with TPA, and down-regulation of PKC after longer exposure to TPA. Collagen IV and fibronectin treatment of 10T1/2 cells induced MAP kinase, (MEK) kinase in the presence and in absence of FCS. Signal transduction pathway depending on protein kinase C and integrin receptors activation appears to facilitate migration of 10T1/2 cells and may be involved in the mechanism of the escape from contact inhibition of movement.

Endothelin-1 and 5-fluorouracil-induced cardiotoxicity.

Cardiotoxicity is an uncommon side-effect of 5-FU-based chemotherapy. Coronary artery vasospasms have been postulated to be involved in the pathogenesis of this rare but serious problem. We found high plasma levels of ET-1, a potent natural vasoconstrictor, in two patients who experienced two of the commonest clinical manifestations of 5-FU-induced cardiac toxicity--i.e., angina pectoris and chronic heart failure. We, therefore, propose ET-1 as the ultimate mediator of this toxicity, even though the mechanism of ET-1 increase in peripheral venous blood is still unknown. Finally, another important question still remains unresolved: is the release of ET-1 from normal coronary endothelial cells the prime cause or simply the consequence of 5-FU-related cardiotoxicity?

The relationship of HLA-DR, CD38 and CD71 markers to activation, proliferation and differentiation of some human leukemia and lymphoma cells.

We investigated the expression-percentage as well as MESF values ("molecules of equivalent soluble fluorochrom" that represent approximately the density of marker expression) of HLA-DR, CD71 and CD38 markers in some human leukemias (ALL, AML, CLL, CML) and lymphomas. They are non-lineage restricted and are supposed to be activation markers except for cases where they represent pathological phenotype like HLA-DR in pre B-ALL, CD38 in some M0 AML or in plasmocytoma or CD38 and CD71 in less mature T-ALL. We used flow cytometry, immunofluorescent staining, DNA staining by propidium iodide and quantification by calibration particles. We demonstrated increased MESF values of HLA-DR compared with controls in all investigated disorders, what could have a prognostic value. We demonstrated significantly higher MESF values of HLA-DR in cALL (37,300-46,000) in comparison with AML (9400-12,400), what could represent another important parameter when distinguishing between these two groups of leukemia. In cells of CML patients with lower CD38% and CD71% increased MESF values (5100 for CD38 and 7900 for CD71), were found while in some T-ALL, AML and cALL patients with high percentages of CD71 and CD38 there were lower MESF values what could indicate a possible connection of higher stage of cell maturation with increased density of CD38 and CD71 markers. We investigated possible relationship between percentage of expression of HLA-DR, CD38 and CD71 and proliferation rate by DNA analysis of the cell cycle. In a group of non-Hodgkin's lymphoma patients, there was no significant increase of proliferation index of malignant cells compared with control. The correlation between percentage of expression of mentioned parameters and proliferation index was not significant. In one patient with Burkitt's lymphoma we demonstrated significant increase of proliferation index of CD71+ subpopulation compared with CD71- one, what indicates that in aggressive form of NHL CD71 can be evaluated not only as activation but also as proliferation marker.

Early changes in flow cytometric DNA profiles induced by californium-252 neutron brachytherapy in squamocellular carcinomas of the uterine cervix.

Ninety-five squamocellular carcinomas of the uterine cervix, clinical Stages II and III, were treated by either four schedules combining 252-californium neutron-gamma-radiotherapy with different proportions of a neutron component (9, 6 and 3 Gy) or gamma-irradiation alone. Flow cytometric DNA profiles were obtainable in 72 cases before treatment and 56 cases were monitored for DNA content by flow cytometry (FCM) in weekly intervals by analysis of sequential microbiopsies for one month during and after radiotherapy. DNA aneuploidy was reduced from 40% (25/63) to 19% (9/47) one week within therapy in neutron-treated groups, but not after initial gamma-radiotherapy alone. Extinction of DNA aneuploid subpopulations occurred after neutron therapy in all remaining aneuploid tumors (9/9) during further monitoring, but only in 40% (2/5) of tumors after sole gamma-irradiation. In contrast, proliferation index by more than 50% was more often achieved in groups with a higher gamma-radiation component than after neutrons only. When all therapy-induced DNA flow cytometric events are taken together for evaluation of the effects of various radiotherapy schedules, it appears that the regimen with the maximal neutron dose may not be optimal for all tumors. It is hypothesized that the differences in the early flow cytometric DNA profiles may select the DNA aneuploid squamous cell uterine cervical carcinomas as candidates for combined neutron-brachytherapy, while highly proliferating DNA near-diploid tumors may profit more from treatment with a higher gamma-radiotherapy component. However, these early DNA flow cytometric findings need to be correlated with clinical course of the disease to validate this hypothesis, a process which will be completed at the end of the expected five-year clinical outcome in 2000.

Cytoplasmic liver cell inclusions--a typical feature of porphyria cutanea tarda--are absent in porphyria-related hepatic neoplasias.

Crystalline cytoplasmic needle-shaped inclusions in hepatocytes are considered to represent a specific morphological feature of porphyria cutanea tarda (PCT) and experimental PCT-like porphyrias. The cytoplasmic inclusions, however, are absent in hyperplastic hepatic nodules and hepatocellular carcinomas arising in the course of these conditions. It is assumed that porphyrins and related substances accumulated in hyperplastic and neoplastic hepatic lesions differ from those found in non-neoplastic liver tissue: the highly carboxylated porphyrins are stored in both sites, the crystal-forming substance only in non-proliferating liver tissue.

Dose-response relationship for elective neck irradiation of head and neck cancer--facts and controversies.

The aim of this study is to assign dose-response relationship for subclinical neck metastases of squamous cell head and neck cancer based on extensive survey of 24 data sets collected from the literature. Neck relapse rates (NRR) without and after elective (ENI) or preoperative irradiation were estimated for each site and stage of primary tumor and the reduction in neck relapse rate was calculated. An average NRR without ENI was 22% (12-35%) and only 2.5% (0-10%) after the ENI with total dose of 46-50 Gy which gives high reduction rate in the risk of neck recurrences being on the average 89% and 42% (0-46%) after preoperative irradiation using 22-30 Gy. Dose response curve for elective and preoperative irradiation have shown that 50 Gy in 2 Gy fraction reduces the incidence of neck relapses in the N0 patients by more than 90% and only by less than 50% after total doses lower than 30 Gy. No correlation between the risk of neck metastases without ENI and the reduction in neck relapses after ENI was found.

Immuno-ultrastructural localization of p53 protein in patients with laryngeal carcinoma.

Protein p53 was localized ultrastructurally with 5 nm gold-streptavidin particles in cells of laryngeal carcinoma embedded in Epon 815. Postembedding technique to study p53 protein was used. Protein p53 was found predominantly in nucleus of the cells but the label was also observed in cytoplasm of the cells. Five of 15 samples from patients with laryngeal carcinoma showed positive labeling for p53, (33.3% of all examined samples). Controls of tumor cells incubation with normal mouse serum showed no labeling with gold streptavidin particles.

Immunohistochemical analysis of the functional status of estrogen receptor cascade in breast cancer.

Hormone receptor expression in human breast cancer cells does not always reflect tumor response to therapy. Thus, relations between hormone receptor status and other parameters need further examination. The aim of this study was to test the ability of estrogen receptors (ER) to induce progesterone receptor (PR) synthesis as well as to test their role in the regulation of cell proliferation. Measurement of the relation between expressions of ER and the estrogen receptor related protein p29 (ERRP) was a further goal. The results show that some hormone receptor phenotypes are closely related to tumor proliferative activity: in the ER-group, especially ER-PR-phenotype, proliferative activity shows no obvious relationship to phenotype status, suggesting that proliferation in this group probably is not under estrogen control, while in the ER+ group, PR expression was related to reduced proliferation. There was no clear association between ERRP and nuclear ER but the highest ERRP expression was most closely related to ER negative (ER-) or slightly positive (ER +/-) hormone receptor statuses. Tumors with these phenotypes are known to have a poorer prognosis. The conclusion drawn is that simultaneous estimation of proliferative activity, ERRP p29 expression and a comparison with ER/PR hormone receptor phenotype, could provide pathologist with a valuable tool for predicting hormone response and prognosis in breast cancer patients.

Bcl-2 family proteins and leukemia. Minireview.

The present status of Bcl-2 family proteins action and their role in leukemia and lymphoma is reviewed here in short. The Bcl-2 is an oncogenic protein that acts by inhibiting programmed cell death (apoptosis). In this article a timely review of the emerging mechanisms by which Bcl-2 and homologous family proteins might suppress cell death is presented. There have been reports that Bcl-2 and related anti-apoptotic proteins can function as a channel in the mitochondrial membrane and as an adaptor protein that can protect cells from cytotoxic agents. A dual function now seems likely, and interactions between Bcl-2 and other proteins are supposed. The Bcl-2 family proteins have assumed an important role in leukemia and lymphoma research. The observations reviewed in this article suggest an important role of dysregulated Bcl-2 expression in the pathogenesis and prognosis of at least some types of leukemia and lymphoma. The Bcl-2 family proteins are important regulators of apoptosis that constitute a novel mechanism of chemoresistance in cancer.

Oncogene amplification and expression in pediatric solid tumors.

Oncogene amplification and expression and their mutual relationship was analyzed in 92 pediatric tumors by Southern and Northern blot hybridization with N-MYC, ERB A, ERB B, N-RAS and Shb probes. Amplification and overexpression was associated with more advanced clinical stages of tumor, especially in neuroblastomas, rhabdomyosarcomas and ganglioneuroblastomas. The most frequent alteration observed was N-MYC amplification together with overexpression. N-RAS amplification was not detected, while the overexpression of this oncogene was found in 3 cases. Neither amplification nor overexpression was revealed in any specimen of hepatoblastoma or hepatocellular carcinoma. We suggest that oncogenes overexpression provides more accurate prognostic information than amplification.

Phenotypic heterogeneity and aberrant markers expression in T-cell leukemia.

For exact determination of lineage assessment there is a need of surface membrane and intracellular (cytoplasmic and nuclear) immunophenotyping performed by flow cytometry. We evaluated in detail the results of surface and intracellular immunophenotyping of 34 T-ALL cases. The great heterogeneity of T-cell differentiation markers has been observed which did not allow relevant subclassification of T-ALL according to the existing subclassification schemes and the proposed three-stage model of physiological T-cell differentiation. Therefore, a simplified classification based on the CD3 marker expression either on cell membrane or in cytoplasm has been created with allocation of T-ALL into two main phenotypic groups. From 34 in detail examined T-ALL cases a great deal-27 (79%) belonged to an immature phenotype (Stage I) and only 7 (21%) expressed more mature phenotype (Stage II). Simultaneously the presence of atypical/aberrant T-cell phenotypes has been studied. We showed that in T-ALL it was possible to specify some cases with leukemia-associated phenotype with coexistence of atypical markers which are absent in nonleukemic cells. In a majority of cases early B-lineage marker (CD10) and in a smaller proportion of them non-lineage associated marker (CD34) were observed. Myeloid marker CD13 was observed in one case of the immature T-ALL, together with CD10 and CD34. As these atypical markers were present through all differentiation stages of T-ALL we obtained a strong evidence that they might represent an abnormal rather than an immature phenotype. The prognostic significance of T-ALL subtypes and aberrant markers coexpression have been discussed. Simultaneously it was shown that quantitative immunofluorescence could provide an additional important diagnostic marker also in T-ALL cases.

Is T-cell acute lymphoblastic leukemia still a high risk leukemia in children?

In a group of 21 children with T cell ALL we compared the clinical picture and laboratory finding in a subgroup of 13 patients with less mature (mCD3 negative) and a subgroup of 8 patients with mature (mCD3 positive) phenotypical type and the therapeutic response in relation to the stage of thymic differentiation of the blastic cells as well. We could not find any significant differences concerning the presence or absence of mediastinal thymic mass, organomegaly, WBC count, morphology of the blasts and their acid phosphatase and PAS reaction between cases with less mature and mature type of thymic differentiation. Concerning the therapeutic response, children with mature type of T-ALL have shown at 5 years significantly higher event free survival rate, in comparison with the group of patients with less mature type of T cells. Overall survival rate was also higher in the first group, but statistically not significant.

Expression of proliferating cell nuclear antigen (PCNA) and p53, bcl-2 or C-erb B-2 proteins on Reed-Sternberg cells: prognostic significance in Hodgkin's disease.

Expression of proliferating cell nuclear antigen (PCNA) as well as p53, bcl-2 and C-erb B-2 genes protein products on Reed-Sternberg/Hodgkin's (R-S/H) cells was analyzed by immunohistochemistry in 65 patients with Hodgkin's disease (HD). Their significance as markers of clinical malignancy and prognostic factors was evaluated. Positive reaction for PCNA was present in 57 cases (87.7%), for p53 in 42 (64.6%), for bcl-2 in 41 (63.1%), and for C-erb B-2 in 38 cases (58.5%) of HD. The high proliferate PCNA index and high expression of p53 and bcl-2 correlated with poor response to the treatment. Expression of both p53 and bcl-2 oncoproteins negatively influenced overall survival and disease free survival. Indexes of PCNA, p53 and bcl-2 were significantly higher in patients with advanced disease then in early clinical stages. In LP type of HD the lowest indexes of PCNA or bcl-2, and even lack of bcl-2 expression on R-S/H cells were observed. There was no correlation between expression of C-erb B-2 and response to the treatment, time of survival, clinical stage or histopathological types of HD. Statistical analysis let us to the conclusion, that indexes of PCNA, p53 and bcl-2 expression can be taken into consideration as a new prognostic factors in Hodgkin's disease. C-erb B-2 protein expression seems to be of no value for prognosis in HD.

Embolization and serum lysozyme activity in renal cancer.

The aim of the study was to determine the effect of renal tumor embolization on nonspecific immunity by evaluating lysozyme activity and leucocytosis in 45 patients and 40 healthy people. Lysozyme activity was assessed in the non-diluted serum (A1) and in the tenfold diluted serum (B1) prior to embolization and after embolization (A2, B2) and in control group. Prior to embolization, lysozyme activity was lower in the experimental group (A1 and B1), compared to the control groups, the differences being statistically significant (p < 0.05). After embolization, the activity became normalized (A2), reaching the control value and even exceeding it (C) in the diluted serum (B2). Leucocytosis prior to embolization (L1) resembled that of control group, increasing slightly after embolization (L2). The differences observed in the changes in lysozyme activity and leucocytosis were statistically significant (p < 0.05). Our findings indicate an inhibitory effect of the neoplastic process on nonspecific immunity. Embolization causes ischemic necrosis of tumor and products of neoplastic tissue disintegration exert a stimulating effect on granulopoiesis, by increasing the turnover of neutrophilic granulocytes. Granulocytic-monocytic infiltrations in tumor stroma are the source of lysozyme, enhancing not only local but also systemic immunity, which is manifested in the increased lysozyme activity in blood serum.

Glutathione and lipid peroxidation levels in human breast tumors.

The levels of reduced glutathione (GSH) and lipid peroxidation (LP) of breast tumor and surrounding tumor free (normal) tissues of 39 breast cancer female patients with infiltrating ductal carcinoma and the relationship between these two parameters were investigated. Large interindividual variations in the levels of GSH and LP were found in both tumor and normal tissues. The mean GSH levels of tumors were significantly higher than those of normal tissues. This tendency did not change with the stage and grade (excluding grade 1) of the malignancy, menopausal status and chemotherapy treatment. No correlation was found between GSH level and stage or grade of malignancy (p > 0.05). However, although more than half of the tumor samples (23/39, 59%) had higher LP levels than their corresponding normal tissues, no significant difference was noted between the mean LP levels of tumor and normal tissues. This tendency did not change with the stage and grade of the malignancy, and menopausal status and chemotherapy treatment. No relationship was observed between the LP level and stage or grade of malignancy (p > 0.05). Overall, no association existed between the levels of GSH and LP in tumors (p > 0.05). These results reveal that the GSH, but not LP, could be a marker of breast malignancy and that the increase in GSH level is not sufficient to lower the LP level in human breast tumors.

Photodynamic therapy for gastrointestinal tumors using three photosensitizers--ALA induced PPIX, Photofrin and MTHPC. A pilot study.

Photodynamic therapy (PDT) produces localized necrosis with light after prior administration of a photosensitizing drug. As PDT lesions in the gastrointestinal tract heal well, the technique is suitable for repeated endoscopic use. In this study we used PDT to treat benign and malignant gastrointestinal tumors in esophagus, duodenum and rectum in 22 patients, who refused or were not suitable for surgery. Patients were sensitized with 0.15 mg/kg of body weight with mesotetrahydroxyphenylchlorin i.v. m-THPc (2 patients), with 2.0 mg/kg Photofrin i.v. (4 patients) or 60 mg/kg 5-aminolevulinic acid orally ALA (which is converted in vivo to active derivate protoporphyrin IX-PRIX) in fractionated doses (16 patients). Laser treatment was performed 2 days after Photofrin, 2 and 4 days after mTHPc and 4 hours after ALA, using a metal vapour laser (628 nm, 50-150 J/cm2 for ALA and Photofrin, 650 nm and 10-15 J/cm2 for mTHPc). Using ALA, the necrosis was only superficial (up to 1.8 mm depth). Four patients treated with Photofrin showed deeper necrosis, in one case of 8 mm colon cancer complete response, in three cases 1-1.5 cm adenomatous polyps involving the ampulla Vateri 50% longer term reduction in size-seen endoscopically. Two patients with rectal villous adenomas treated with mTHPc showed 60-80% reduction in size (observed endoscopically) within few days after PDT, with better effects for treatment carried out 4 rather than 2 days after the sensitization. In all patients the healing was without any complications. Photofrin and mTHPc work better, but cause cutaneous photosensitivity lasting 12 and 5 weeks, respectively. Better results with ALA are possible when using higher drug doses or modified light dosimetry. PDT is a promising treatment for small localized tumors in patients unsuitable for surgery, but further work is required to optimize the treatment conditions.

Cloning, expression, purification of rat tumor necrosis factor and demonstration of its antitumor activity in Bomirski amelanotic melanoma.

In order to analyze the effect of tumor necrosis factor (TNF) on the growth of Bomirski melanomas of hamster, we cloned, expressed and purified to homogeneity the rat tumor necrosis factor. The detailed procedure of chromatographic purification of the cytokine is reported. Polyclonal antibodies generated against the recombinant rat preparation were able to neutralize the rat and hamster TNF. We have found that the preparation of rat TNF is active in vivo and inhibits the growth of a Bomirski (Ab) amelanotic melanoma. Thus, a novel model system has been developed, which should facilitate analysis of antitumor and immunomodulatory function of TNF in cancer hosts.

Protection from pan masala induced genomic damage by beta-carotene and retinoic acid--an in vitro experience.

Cytogenetic studies in Chinese hamster ovary (CHO) cells using aqueous and organic extracts of pan masalas, as well as genomic damage observed among pan masala consumers have conclusively shown genotoxic potential of pan masala-a dry complex mixture of areca nut, lime, catechu, cardamom, unspecified flavoring agent, etc., often containing tobacco in it. Tobacco and areca nut, major ingredients of pan masala, are closely associated with oral cancer. The most widely studied group of compounds in the field of chemoprevention is retinoids which includes natural vitamin A, beta-carotene and synthetic derivatives of vitamin A. In the present study, antigenotoxic effect of beta-carotene (BC) and retinoic acid (RA) on genotoxic potential of pan masala have been evaluated in CHO cells with the help of sister chromatid exchange (SCE) frequency and chromosome aberration (CA) frequency as cytogenetic markers. The pulse treatment with pan masala plain/pan masala-tobacco (PM/PMT) extract in combination with either BC or RA yielded lower frequencies of CA and SCE in CHO cells as compared to the cultures treated with aqueous extract fo pan masalas alone. This antigenotoxic effect of BC and RA was more pronounced when treatment was given continuously for a longer duration. Thus, these results indicated possibility of using BC and RA to decrease the risk of oral cancer among pan masala chewers.

Is high dose methotrexate without irradiation of the brain sufficiently effective in prevention of CNS disease in children with acute lymphoblastic leukemia?

We present 5-year results of treatment in 93 children suffering from acute lymphoblastic leukemia using two therapeutic protocols containing multidrug chemotherapy including high dose methotrexate. We could ascertain different results in standard and high risk patients. In a group of 62 children with standard risk we observed improvement in complete remission rate being 98.9% after induction phase of therapy, only one patient died on septicemia. Relapse rate in this group was 21.2% and that 14.7% in the bone marrow and 6.5% in CNS and no testicular relapse at all. In the group of 31 children with high risk leukemia all patients achieved complete remission. Only one of them died on acute pancreatitis due to toxicity. Overall relapse rate in this group was 28.9% with 12.8% of medullary relapse and 16.1% of CNS relapse. The last one was significantly higher than in the previous study when brain irradiation was a part of therapeutic procedure. It seems that this treatment is effective mainly in the standard risk leukemia, however, in the high risk leukemias this procedure appears to be less effective in preventing CNS leukemia. In this group of patients irradiation of the brain need to be enclosed in the therapy.

About three cases of plagiarism.

Increasing DNA repair capacity in bone marrow by gene transfer as a prospective tool in cancer therapy.

Resistance of tumor cells to alkylating anticancer agents that produce adducts at the O6 position of guanine in DNA, the O6-alkylating agents, correlates with the expression of O6-alkylguanine-DNA alkyltransferase (ATase). O6-benzylguanine and related pseudosubstrates are able to inactivate human ATase in vitro and in vivo and they are being tested as chemotherapeutic adjuvants for enhancing the effectiveness of O6-alkylating drugs. On the other hand, the clinical consequences of ATase depletion may be fatal for some sensitive systems e.g. hematopoiesis. To overcome this problem, strategies for the protection of primary bone marrow cells by targeted transfer of pseudosubstrate-resistant ATase genes have been considered and recently achieved at the laboratory level. This approach could therefore be now extended to a clinical cancer gene therapy program.

Application of NMR spectroscopy in biochemical studies of tumor cells sensitive and resistant to anticancer drugs.

Drug resistance is a prominent problem of cancer therapy. Differences in quantity and quality of many metabolites in normal and malignant cells and their changes after treatment by anticancer drugs can be detected by nuclear magnetic resonance (NMR) both in vivo and in vitro. The results of in vivo and in vitro 1H, 13C, 19F and 31P NMR spectroscopy and their correlation with the degree of resistance to anticancer drugs are discussed. Monitoring of treatment and development of drug resistance by this non-invasive method could be useful not only in cancer research related to drug resistance but also in clinical medical oncology.

Expression of cytokine receptors on different myeloid leukemic cells.

We have studied the expression of cytokine receptors CD25 (IL-2Ra,55kD), CD116 (hGM-CSRF,145kD), CD117 (CSFR,145kD), CD120a (TNFR,55kD), CD120b (TNFR,75kD), CD121a (IL-1R, type I, 80kD), CD123 (IL-3R), CD124 (IL-4R, 140kD), CD126 (IL-6R, 80kD), CDw127 (IL-7R, 75kD), CDw128 (IL-8R), CD130 (gp130 subunit), CD131 (common beta), CD134 (OX40) and also CD95 (Fas antigen) on the myeloid leukemic cells. Cells from peripheral blood or bone marrow of 30 patients with disorders in myeloid lineage included mostly acute myeloid leukemias (with high leukocyte count and percentage of blasts) were analyzed for the expression of surface membrane molecules by indirect immunofluorescence method evaluated by flow cytometry. The findings indicate that some monoclonal antibodies have a reactivity against cytokine receptors of pathological cells in individual cases, but with very variable qualitative and quantitative (number copies/cell) expression (preliminary results). The leukemic cells demonstrate unique cytokine receptor profiles, which reveal the great diversity of immunophenotypes within the main functional characterization of blood malignancies. The immunophenotype heterogeneity of leukemic cells has proved to be much greater than to match with existing classification criteria. This fact could raise the necessity of further evaluation and specification of cytokine markers of the myeloid acute leukemias. On the other hand, detection of cytokine receptors on the leukemia cells is important for cytokine therapy.

Staurosporine enhanced benzamide riboside-induced apoptosis in human multidrug-resistant promyelocytic leukemia cells (HL-60/VCR) in vitro.

The inosine monophosphate (IMP) dehydrogenase inhibitor benzamide riboside (BR) induced apoptosis (detected with the aid of flow cytometric identification of cells with sub-G0 DNA content and increased side angle light scatter) equally or slightly more intensively in the multidrug-resistant human promyelocytic leukemia cell line (HL-60/VCR: MDR-1 gene, Pgp positive) in comparison with the parental drug sensitive HL-60 cells. Staurosporine alone induced relatively low level of apoptosis in parental HL-60 cells but higher level (approximately 35%) of apoptosis in multidrug-resistant HL-60/VCR cells after 24 hour induction. The combination of benzamide riboside and staurosporine induced in both drug-sensitive and drug-resistant HL-60 cells a marked proportion of apoptotic cells already after short (6 hour) induction (more than 30% of apoptotic cells).

The pathomorphology of a human xenotransplanted basaloid squamous cell carcinoma.

To elucidate some factors related to the malignant phenotype of an oral tumor with mixed cell population the question has been raised whether the biological behavior of the basaloid or the squamous cells show any difference in an immunosuppressed host organism. Basaloid squamous cell carcinoma (BSCC) surgically removed from sublingual location was xenotransplanted either subcutaneously or in the oral submucosa and the histology, ultrastructures, LDH isoenzyme pattern were investigated. The epithelial origin of the established tumor line (HTB-1) could be recognized according to the characteristic epithelial ultrastructures, while the type of the LDH isoenzymes proved its human origin. The squamous cell population dominating the parent surgical specimen of BSCC regressed during xenotransplantation in the subcutan location, on the contrary the basaloid cells grew and maintained the tumor. Interestingly the basaloid cells transplanted from the subcutis to the oral submucosa generated a squamous cell population with an infiltrative growth pattern. The xenografted BSCC offer a promising model to investigate the contribution of each cell populations in the malignant phenotype. The presented data indicate that the basaloid cells are responsible for maintaining the tumor cell population, but certain malignant features (i.e. infiltrative growth) is associated to the squamous cells which are generated from the basaloid cells only under specific circumstances. Thus this particular model system showed that different malignant features could be associated to the basaloid and to the squamous cell component.

A 65 kDa oncofetal protein (p65), proliferating cell nuclear antigen (PCNA) and Ki67 expression in breast cancer patients.

Paraffin-embedded tissue slides from 89 infiltrating ductal breast carcinoma, 10 fibrocystic disease and 10 fibroadenoma were assessed immunohistochemically using monoclonal antibodies against human p65 antigen and polyclonal antibodies against p65-like protein present in fetal bovine serum. We did not find any evident differences in p65 detection by polyclonal and monoclonal antibodies, however, monoclonal antibody seems to be more specific. This factor is not induced by cellular proliferation associated with nonneoplastic diseases what was confirmed by immunohistochemical analysis of expression of p65 protein and well know markers of proliferation (proliferating cell nuclear antigen--PCNA and Ki67). It was established that there is no correlation between p65 and PCNA or Ki67 expression. High proliferating indexes (PI) for PCNA (PI-PCNA) or Ki67 (PI-Ki67) may help in selection of tumors with high proliferating activity independently from histological grade of malignancy established by routine methods. The estimation of p65 protein may be useful in the selection of precancerous changes and more differentiated ductal cancer of the breast what raises the possibility that p65 antigen may be helpful in the screening examination of women with high risk for cancer development.

Inhibition of apoptosis is the cause of resistance to doxorubicin in human breast adenocarcinoma cells.

In our previous paper we have described the isolation and characterization of a doxorubicin (DOX) resistant subline of breast adenocarcinoma SC6 cells. These cells were obtained after the treatment with low, clinically relevant doses of doxorubicin. They became cross-resistant to different wide used cytostatics. The expression of several genes involved in mitotic signal transduction, as well as cathepsins D and L, was similar in both parental and doxorubicin treated cells. The aim of this study was to examine the molecular mechanisms involved in resistance of these cells to doxorubicin. Activity of plasma membrane Pgp was examined in parental and resistant cells due to rhodamine-accumulation assay. The involvement of glutathione (GSH) and glutathione S-transferase (GST) in resistance to doxorubicin was determined in MTT modified assay due to the addition of specific inhibitors: buthionine sulfoximine (for GSH) or ethacrynic acid (for GST). The kinetic of apoptosis was followed after the treatment with DOX in control and SC6 cells by fluorescent microscope. The occurrence of apoptosis was confirmed by analysing DNA fragmentation in agarose gel. Our results indicate that P-glycoprotein, glutathione or glutathione transferases were not involved in resistance of SC6 cells to doxorubicin. However, the apoptosis was inhibited in doxorubicin-resistant cells. Therefore, even low doses of doxorubicin can induce the resistance to this drug due to inhibition of apoptosis.

Expression of CD10, CD19 and CD34 markers in bone marrow samples of children with precursor B-cell acute lymphoblastic leukemia in clinical and hematological remission.

Long-term follow-up of the rate of CD10, CD19 and CD34 antigens expression compared with the percentage of lymphocytes and blastic cells in 196 bone marrow specimens of 91 children with early B-cell acute lymphoblastic leukemia has been performed. It was shown that during a five year period there were no significant differences concerning the percentage of CD markers and the percentage of lymphocytes and blastic cells except those in the 4th year of clinical and immunological follow-up--when increase of lymphocytes and CD19 marker percentage have been observed. Consensus, i.e. more than 20% CD markers positivity associated with more than 5% blasts (positive consensus) or less than 20% CD markers positivity combined with less than 5% blasts (negative consensus) was ascertained in 92.8% of cases. Disagreement, i.e. the rate of CD markers over 20% combined with less than 5% blasts was found in 14 (7.2%) patients. This finding present in the initial phase of the disease could be considered as a sign of not complete remission, in contrast to the finding in children who completed chemotherapy and were in long-term hematological remission, in which the increase of CD markers could be considered as a sign of increased regeneration activity of bone marrow after chemotherapy induced medullary aplasia. Anyway, the increase of CD10, CD19 and CD34 antigens in bone marrow samples over 20% should be evaluated with caution. In these cases, mainly in children with long-term hematologic remission the examination should be repeatedly performed and/or more sensitive methods for detection of minimal residual disease should be applied. In control group of 20 children without leukemia the rate of CD markers in the bone marrow was always under 20%.

Immunophenotypic characteristics of T-acute lymphoblastic leukemia cells in relation to DPP IV enzyme expression.

In the present study we have examined immunophenotypic characteristics ofT-acute lymphoblastic leukemia (T-ALL) cells in relation to the expression of enzyme dipeptidyl peptidase IV (DPP IV). Peripheral blood and bone marrow cells of T-ALL patients at diagnosis were estimated. Cell surface markers were detected by a standard immunofluorescence assay and FACStar flow cytometry using a broad panel of monoclonal antibodies to define T-cell immunophenotype. DPP IV activity was investigated in phenotypically defined T-lymphoblasts. Association between DPP IV expression and proliferation was monitored by the expression of CD71 and CD38, which could be considered as markers of activation and proliferation, and by the silver-staining of nucleolar organizer regions-related proteins (argyrophilic proteins). Lymphoblasts, divided according to the presence or absence of DPP IV activity revealed remarkable heterogeneity in the immunophenotypic features. The vast majority of DPP IV positive T-ALL cases expressed CD4, CD8, CD7, CD5, CD2 along with CD71 and CD38 antigens, but the cells were surface membrane CD3 antigen negative. The phenotype of DPP IV negative cases displayed membrane CD3 antigen and variable expression of CD4 and CD8. CD71 and CD38 were frequently negative. It appears, that DPP IV active cells form the population with immature phenotype, as evidenced by mCD3 antigen absence. Relation between DPP IV positive cells and proliferation activity of T-blasts was observed, given by the presence of CD71 and CD38 positivity and overexpression of argyrophilic proteins (AgNORs). In conclusion, our study indicates a close relationship between DPP IV activity and the features ofT-cell immaturity. Association among DPP IV, CD71, CD38 and AgNORs might reflect possible relationship between immature phenotype and proliferative ability of blast cells in T-ALL patients.

Evaluation of potential carcinogenicity of steroidal alkaloids from Veratrum album L. by the DC polarography method.

The presented work is devoted to the study of polarographic reduction in the series of 13 alkaloids isolated from various parts of Veratrum album subsp. lobelianum. The used compounds were evaluated from the point of view of their potential carcinogenicity in anhydrous N,N-dimethylformamide (DMF) by the method of DC polarography. All compounds were reduced during an one two-electron irreversible step. Their potential carcinogenicity characterized by a parameter tg alpha value determined in the presence of alpha-lipoic acid ranged from the highest value 0.257 obtained for the solanidane skeleton containing rubijervine to the value 0.070 for jervine. The tg alpha value determined for rubijervine (0.257) is comparable with the tg alpha of naphto-(2',1',2,3)fluoranthene (0.270)-compound classified by IARC as possible carcinogen for human. The tg alpha values determined for other alkaloids were relatively low and they do not indicate any possible carcinogenic activity.