Lonidamine as a modulator of taxol activity in human ovarian cancer cells: effects on cell cycle and induction of apoptosis

The ability of lonidamine (LND), an energolytic derivative of indazole-carboxylic acid, to modulate the cytotoxicity of Taxol (TX) was investigated in the A2780 human ovarian cancer cell line. Different cytotoxicity results were obtained as a function of treatment schedule. Specifically, TX followed by LND produced synergistic effects. Conversely, antagonistic effects were recorded when drugs were given simultaneously or according to the opposite sequence. TX induced an oligonucleosomal DNA fragmentation typical of the apoptotic process. The extent and the kinetics of DNA cleavage in samples treated with the taxane alone were similar to those of samples treated with the TX-LND sequence. Activation of Yama protease and degradation of poly (ADP-ribose) polymerase were not observed after individual or combined treatment. LND did not appreciably modify the effect exerted by TX on proteins involved in cell cycle progression (i.e., inhibition of p34cdc2 expression) and apoptosis (i.e., upregulation of wt p53 and transactivation of p21waf1), and only caused a slight induction of the Bax protein. LND alone did not affect tubulin polymerization in A2780 cells and, when administered after a 24 hr TX exposure, did not appreciably alter the extent of tubulin polymerization induced by the taxane. Although additional studies are needed to define the molecular basis of the TX-LND interaction, our results suggest that LND can positively modulate the antitumor activity of TX in ovarian cancer cells and indicate that the energolytic is potentially useful in combination therapy including the taxane in ovarian cancer patients.

A review of immunofluorescent patterns associated with antineutrophil cytoplasmic antibodies (ANCA) and their differentiation from other antibodies

AIM

To describe the neutrophil fluorescent patterns produced by antineutrophil cytoplasmic antibodies (ANCA) with different antigen specificities, and by other auto- and alloantibodies.

BACKGROUND

Most sera from patients with active generalised Wegener's granulomatosis result in diffusely granular cytoplasmic neutrophil fluorescence with internuclear accentuation (cANCA) and proteinase 3 (PR3) specificity. About 80% of the sera from patients with microscopic polyangiitis result in perinuclear neutrophil fluorescence with nuclear extension (pANCA) and myeloperoxidase (MPO) specificity, or a cANCA pattern with PR3 specificity. However, many different neutrophil fluorescence patterns are noted on testing for ANCA in routine immunodiagnostic laboratories.

METHODS

Sera sent for ANCA testing, or containing a variety of auto- and alloantibodies, were studied. They were examined by indirect immunofluorescence according to the recommendations of the first international ANCA workshop, and for PR3 and MPO specificity in commercial and in-house enzyme linked immunosorbent assays (ELISA).

RESULTS

Sera with typical cANCA accounted for only half of all neutrophil cytoplasmic fluorescence. Other sera had "flatter" fluorescence without internuclear accentuation, and the corresponding antigens included MPO and bactericidal/permeability increasing protein (BPI), but were usually unknown. Peripheral nuclear fluorescence without nuclear extension occurred typically when the antigens were BPI, lactoferrin, lysozyme, elastase, or cathepsin G. Most types of ANA were evident on ethanol fixed neutrophil nuclei. AntidsDNA, antiRo, and antilamin antibodies resembled pANCA. Antimicrobial and antiribosomal antibodies produced cytoplasmic fluorescence, and antiGolgi antibodies, a pANCA. Sera from patients with anti-smooth muscle antibodies were associated with cytoplasmic fluorescence. There was no neutrophil fluorescence with anti-skeletal muscle and anti-heart muscle antibodies, anti-liver/kidney microsomal, antithyroid microsomal, or antiadrenal antibodies. Alloantibodies such as antiNB1 typically resulted in cytoplasmic fluorescence of only a subpopulation of the neutrophils.

CONCLUSIONS

The ability to distinguish between different neutrophil fluorescence patterns, and the patterns seen with other auto- and alloantibodies is helpful diagnostically. However, the demonstration of MPO or PR3 specificity by ELISA will indicate that the neutrophil fluorescence is probably clinically significant, and that the diagnosis is likely to be Wegener's granulomatosis or microscopic polyangiitis.

Bcl-2 protein and prognosis in patients with potentially curable non-small-cell lung cancer

The bcl-2 proto-oncogene functions as a cell death suppressor, and its expression prolongs cell survival by blocking apoptosis. Data available on the clinical relevance of bcl-2 protein expression in patients with non-small-cell lung cancer (NSCLC) are controversial. We analysed the role of bcl-2 protein expression on 6-year relapse-free survival in 229 patients with stage I-IIIa NSCLC (101 squamous cell carcinomas and 128 adenocarcinomas) subjected to surgery, with curative intent. Immunohistochemical analysis was performed on archival material by using a monoclonal antibody anti-bcl-2 (clone 124). Bcl-2 protein expression, which was detected in 22% of the cases, was significantly related to stage, histology and grading, and was an indicator of clinical outcome. The probability of relapse-free survival at 6 years was longer for patients with bcl-2-positive tumours (74%) than for those with bcl-2-negative tumours (57%) (P=0.02). This finding was mainly evident for the subgroups of patients with stage IIIa tumours (P=0.05), squamous cell carcinoma (P=0.03) or moderately/poorly differentiated tumours (P=0.02). However, multivariate analysis by Weibull's regression model indicated that bcl-2 protein expression was not an independent prognostic risk factor in patients with curable NSCLC when the information provided by stage was available.

Induction of apoptosis by taxol and cisplatin and effect on cell cycle-related proteins in cisplatin-sensitive and -resistant human ovarian cells

The effect of taxol (TX) and cisplatin (CDDP), singly or in association, was assessed on two human ovarian cancer cell lines, one sensitive (A2780) and one resistant (A2780 cp8) to CDDP. Cell lines showed a similar sensitivity to TX, whereas different cytotoxicity results were obtained in the two cell lines as a function of TX and CDDP sequence. Specifically, TX followed by CDDP induced simply additive effects in both cell lines, whereas the opposite sequence produced antagonistic effects in A2780 cells and synergistic effects in A2780 cp8 cells. TX, with or without CDDP, induced oligonucleosomal DNA fragmentation typical of the apoptotic process, but the biochemical mechanisms undergoing apoptosis were different in the two cell lines. In fact, in A2780 cells, TX (with or without CDDP) treatment markedly increased p53 as well as p21waf1 protein expression. In A2780 cp8 cells, drug treatment enhanced p53 levels, whereas the expression of p21waf1 was always undetectable at mRNA and protein levels. In the latter cell line, a premature activation of p34cdc2 kinase was observed in correspondence with the drug-induced increase in the S-phase cell fraction. Such an activation was not ascribable to an increase in the overall expression of p34cdc2 or cyclin B1 proteins, but to a dephosphorylation of p34cdc2 kinase. Overall, our results indicate that TX-induced apoptosis in human ovarian cancer cells may be sustained by different events at the cell cycle-control level.

Combined effects of interferon-alpha2a and 13-cis-retinoic acid on human melanoma cell growth and STAT protein expression

We assessed the antiproliferative effects of human recombinant interferon-alpha2a (IFNalpha2a) and 13-cis-retinoic acid (13cis-RA) on two human melanoma cell lines (JR8 and M14). Both cell lines showed a very modest sensitivity to IFNalpha2a and 13cis-RA as single agents. In JR8 cells, the combination of the two compounds consistently produced simple additive effects. In contrast, different effects of the combination were recorded in the M14 cell line depending on the treatment schedule. Specifically, an additive interaction was observed when IFNalpha2a and 13cis-RA were given in sequence, independently of the order of drug administration, whereas a supra-additive antiproliferative effect was seen when cells were simultaneously exposed to the two drugs. Exposure to 1000 IU/ml IFNalpha2a markedly increased the nuclear expression of signal transducers and activators of transcription (STAT) proteins in both cell lines. By itself 10 microM 13cis-RA did not affect STAT protein expression or modify the extent of activation of such proteins by IFNalpha2a. Results from our study showed an enhancement of the antiproliferative activity of IFNalpha2a and 13cis-RA when given in combination and suggest that such an enhancement is not mediated by a concomitant effect of 13cis-RA on STAT protein activation.

p53 expression in human carcinomas: could flow cytometry be an alternative to immunohistochemistry?

Several studies have shown that p53 expression has important clinical implications as an indicator of prognosis and response to chemotherapy or radiotherapy in different human tumor types. Determination of p53 expression by immunohistochemistry (IHC) has been incorporated into routine practice and its reliability has been consolidated. However, flow cytometric (FCM) analysis might represent an important objective and rapid approach. In the present study we determined p53 expression by IHC and FCM on a series of 118 human solid tumors. IHC determination was performed on histological sections and FCM analysis on cell suspensions. Low correlation coefficients (rs from 0.22 to 0.57) were observed between IHC and FCM data from individual tumors. By considering the IHC approach as the gold standard, high sensitivity and low specificity were found for FCM in detecting p53 expression. The FCM analysis of p53 expression and DNA content showed p53-positive cells in all cell cycle phases. Moreover, in most breast, lung, and colon aneuploid tumors (77%), p53-positive cells were detected only in the subpopulations with abnormal DNA content. In conclusion, FCM-p53 expression cannot be used alternatively to IHC determination, and its clinical relevance remains to be validated. Nevertheless, FCM may provide important information about p53 protein expression in the different subpopulations and cell cycle phases. (J Histochem Cytochem 46:41-47, 1998)

The clinical predictivity of biomarkers of stage III-IV epithelial ovarian cancer in a prospective randomized treatment protocol

BACKGROUND

The aim of this study was to define the clinical relevance of functional biomarkers, prospectively assessed in a randomized clinical protocol, in patients with Stage III-IV epithelial ovarian cancer. The protocol compared cisplatin with polychemotherapy that included cisplatin and cyclophosphamide.

METHODS

In a subset of 168 patients with invasive epithelial ovarian cancer cell proliferation was determined by the 3H-thymidine labeling index, DNA ploidy was assessed by flow cytometry, and the expression of p53, bcl-2, and glutathione S-transferase-pi (GST-pi) was evaluated by immunohistochemistry using the antibodies PAb1801, anti-bcl-2, and GST-pi, respectively.

RESULTS

Cell proliferation, DNA ploidy, and the expression of p53, bcl-2, and GST-pi were generally unrelated to one another and unrelated to clinicopathologic features, except for an association between DNA ploidy and the rate of cell proliferation. All biologic variables except bcl-2 were slightly related to tumor grade. DNA ploidy emerged as a predictor of clinical complete response and 3-year overall survival, regardless of treatment type or residual disease. Conversely, except for a favorable outcome for patients with tumors not expressing bcl-2 who were treated with cisplatin, no definitive patterns of predictivity for short term or long term clinical outcomes were observed for the other biomarkers studied.

CONCLUSIONS

DNA ploidy appears to be the most clinically relevant biomarker for epithelial ovarian cancer. More information is needed to understand the role of the other markers studied in this tumor type.

Biological indicators of survival in patients treated by surgery for squamous cell carcinoma of the oral cavity and oropharynx

Squamous cell carcinomas of the head and neck are a heterogeneous group of tumours with regard to anatomical site, natural history and response to various treatments. Assessment of the role of biomarkers as indicators of prognosis or response to treatment is thus complex. In the last decade, different biomarkers have been investigated in the search for objective and reproducible indicators of prognosis. In 69 squamous cell carcinomas of the oral cavity or oropharynx from patients treated with radical surgery alone, we determined cell kinetics, evaluated as in vitro 3H-thymidine labelling index (TLI), p53, bcl-2 and glutathione S-transferase pi (GST pi) expression, by using immunohistochemical methods. The biological variables were unrelated to one another or to established clinical and pathological prognostic factors. Univariate analysis showed that a low proliferative activity was associated to a significantly higher risk of death than that observed in patients with a high TLI, whereas p53, bcl-2 and GST pi expression did not provide prognostic information. Multivariate analysis showed that cell proliferation, gender and nodal status retained their clinical relevance. In the subset of node-negative patients, TLI and p53 expression were indicators of survival. Moreover, the combined analysis of TLI and p53 expression identified a subgroup of node-negative patients with slowly proliferating and highly p53-expressing tumours who died within 1 year of radical surgery. These results indicate that in patients with operable oral cavity and oropharyngeal cancer, biomarkers can provide important information on clinical outcome.

Schedule-dependent modulation of idarubicin cytotoxicity by lonidamine in human lymphoma cell lines

The ability of lonidamine (LND), an energolytic derivative of indazol-carboxylic acid, to modulate the cytotoxic activity of idarubicin (IDA) and doxorubicin (DX) was investigated in two human lymphoma cell lines (H9 and U937). A different pattern of interaction between the drugs was observed as a function of treatment sequence. Specifically, a 24-h postincubation with a non-cytotoxic concentration of LND (75 mu M) increased the activity of a 1-h anthracycline treatment in both cell lines. However, the extent of potentiation for IDA was more than twofold that of DX. No enhancement of anthracycline activity was observed when LND preceded IDA. For comparative purposes, the modulating effect of all-trans-retinoic acid (ATRA) on the cytotoxicity of IDA was evaluated according to different treatment schemes in both lymphoma cell lines. In U937 cells, which undergo monocytic differentiation after exposure to retinoids, a marked increase in LDA activity was obtained following a 48-h postincubation with 1.5 mu M ATRA. No potentiation of anthracycline activity was obtained using the opposite drug sequence. In H9 cells, no significant interference between ATRA and IDA was observed independent of the modality of drug administration. The ability of LND to potentiate IDA activity, and the consideration that LND causes side effects different from those caused by anthracyclines, make this compound an attractive candidate for multidrug combination therapy in hematological neoplasms.

Image and flow cytometric analyses of DNA content in human solid tumors. A comparative study

OBJECTIVE

To compare the sensitivity and potentials of flow and image cytometry in assessing DNA content.

STUDY DESIGN

The study was performed on 152 tumors (oral cavity, uterine cervix, bladder, colorectum, breast). Flow cytometry was carried out on cell suspensions from frozen samples, and the results were expressed as the DNA index. Image cytometry was performed on Feulgen-stained sections, and the results were expressed as the rate of cells exceeding 2.5c or 5c. For colorectal and breast cancers, DNA content by image cytometry was also measured on imprints and was expressed as the DNA index or rate of cells exceeding 2.5c and 5c.

RESULTS

Among flow cytometric diploid tumors, image cytometric analysis performed on histologic sections showed about 80% diploid tumors from the uterine cervix and breast cancers. The frequency decreased to 36% for oral cavity cancers. Generally satisfactory concordance was observed when flow cytometric aneuploid tumors were analyzed. A highly significant correlation was observed between DNA indices observed by flow and image cytometry on imprints.

CONCLUSION

Image cytometry appears more sensitive than flow cytometry in detecting small, aneuploid clones, but its main limitation is the low power in resolving near-diploid cell populations. The results on imprints indicate that image cytometry is a potential alternative approach for small tumor samples.

Prognostic factors for metachronous contralateral breast cancer: a comparison of the linear Cox regression model and its artificial neural network extension

The purpose of the present study was to assess prognostic factor for metachronous contralateral recurrence of breast cancer (CBC). Two factors were of particular interest, namely estrogen (ER) and progesterone (PgR) receptors assayed with the biochemical method in primary tumor tissue. Information was obtained from a prospective clinical database for 1763 axillary node-negative women who had received curative surgery, mostly of the conservative type, and followed-up for a median of 82 months. The analysis was performed based on both a standard (linear) Cox model and an artificial neural network (ANN) extension of this model proposed by Faraggi and Simon. Furthermore, to assess the prognostic importance of the factors considered, model predictive ability was computed. In agreement with already published studies, the results of our analysis confirmed the prognostic role of age at surgery, histology, and primary tumor site, in that young patients (< or = 45 years) with tumors of lobular histology or located at inner/central mammary quadrants were at greater risk of developing CBC. ER and PgR were also shown to have a prognostic role. Their effect, however, was not simple in relation to the presence of interactions between ER and age, and between PgR and histology. In fact, ER appeared to play a protective role in young patients, whereas the opposite was true in older women. Higher levels of PgR implied a greater hazard of CBC occurrence in infiltrating duct carcinoma or tumors with an associated extensive intraductal component, and a lower hazard in infiltrating lobular carcinoma or other histotypes. In spite of the above findings, the predictive value of both the standard and ANN Cox models was relatively low, thus suggesting an intrinsic limitation of the prognostic variables considered, rather than their suboptimal modeling. Research for better prognostic variables should therefore continue.

Modulation of melphalan and cisplatin cytotoxicity in human ovarian cancer cells resistant to alkylating drugs

We investigated the effect of pharmacological modulators on the cytotoxic activity of melphalan and cisplatin in human ovarian cystadenocarcinoma cells sensitive (OAW42) or resistant (OAW42MER) to bifunctional alkylating agents. By filter elution experiments we observed a reduced accumulation and a faster repair of melphalan-induced DNA interstrand cross-links in the OAW42MER resistant cells than in the OAW42 parental, sensitive cells. Moreover, resistant cells were characterized by an increased level of mRNA encoding enzymes involved in the nucleotide excision repair pathway, such as ERCC (excision repair cross complementing)1 and ERCC2. Among the modulators used, the topoisomerase I inhibitor topotecan was able to increase melphalan cytotoxic activity in sensitive and resistant cell lines. Topotecan also positively modulated cisplatin activity, although to a variable extent in the two cell lines, as a function of treatment schedule. The energolytic compound lonidamine markedly enhanced the cytotoxicity of melphalan and cisplatin, with a potentiating effect in the OAW42MER resistant cells almost 2-fold that of in the OAW42 sensitive cells. No significant potentiation was observed by using calcium channel blockers, such as verapamil and nimodipine. Conversely, an increase in melphalan cytotoxic activity was determined by flunarizine in OAW42MER resistant cells and, to a lesser extent, in OAW42 sensitive cells. However, the calcium blocker failed to modulate cisplatin activity in both cell lines.

Expression of p53, glutathione S-transferase-pi, and Bcl-2 proteins and benefit from adjuvant radiotherapy in breast cancer

BACKGROUND

In clinical breast cancer research, the utility of certain biomarkers as predictors of response to surgery, chemotherapy, or hormonal therapy has been studied intensively. Much less research has been done on the relevance of biologic predictors of response to radiotherapy, which represents an effective local-regional treatment for breast cancer.

PURPOSE

The utility of biomarkers involved in DNA damage repair (p53 protein), control of programmed cell death (p53 and Bcl-2 proteins), and cellular detoxification (glutathione S-transferase-pi [GST-pi] enzyme) in predicting local breast cancer recurrence was analyzed retrospectively in two cohorts of breast cancer patients. These patients had had no detectable metastases in the axillary lymph nodes (i.e., node-negative) or in distant sites and had had similar distributions of clinicopathologic and biologic prognostic features. They had been treated by conservative surgery alone (139 case patients) or by conservative surgery followed by adjuvant radiotherapy (496 case patients) during the period from 1984 through 1990.

METHODS

The expression of the p53, GST-pi, and Bcl-2 proteins in the specimens of primary breast tumor obtained from these patients was determined by use of immunohistochemistry; cell proliferation activity and levels of steroid receptors were determined by use of a [3H]thymidine-labeling index assay and the dextran-coated charcoal technique, respectively. The median time of follow-up of patients was 6 years. In the analyses of patient outcomes, only local failures that presented as first events were considered.

RESULTS

After surgery alone, the risk of local recurrence at 6 years was higher for patients with tumors exhibiting elevated levels of p53 and GST-pi protein expression than for patients with low levels (hazard ratio [HR] = 3.1, 95% confidence interval [CI] = 1.3-7.7, two-sided P = .012; HR = 2.7, 95% CI = 1.1-6.4, two-sided P = .026, respectively). Weak or no observable expression of Bcl-2 protein was only suggestive of a higher frequency of local failures. Adjustment for patient age, tumor size, cell proliferation, and estrogen receptor status did not change these findings. Conversely, in the series of patients given conservative surgery followed by radiotherapy, there was no difference in local tumor recurrence between patients with tumors expressing or not expressing each of the three markers.

CONCLUSIONS

Our study provides indirect evidence of a benefit from radiation therapy in preventing local breast cancer relapse, particularly among node-negative patients with tumors that express elevated levels of the p53 or GST-pi proteins or that express little or no Bcl-2 protein.

Cell proliferation-related markers in colorectal liver metastases: correlation with patient prognosis

PURPOSE

We analyzed the relation between phenotypic (DNA ploidy) and functional markers (S-phase cell fraction, p53, and bcl-2 protein expression) and defined their relevance on clinical outcome on a retrospective series of radically resected liver metastases from colorectal cancer.

PATIENTS AND METHODS

Among 104 patients with resectable liver metastases from colorectal cancer, DNA ploidy was determined by flow cytometry, 3H-thymidine labeling index (TLI) by autoradiography, and expression of p53 and bcl-2 by immunohistochemistry.

RESULTS

TLI was a significant indicator for relapse at 4 years from radical surgery, DNA ploidy was a suggestive indicator of clinical outcome, and p53 and bcl-2 expression provided no clinical information. By multivariate analysis, cell proliferation rate and Dukes' stage remained independent prognostic parameters. In the most representative subgroup of patients with H1 liver lesions (86 cases), TLI was always associated with relapse, and DNA ploidy and p53 expression provided discriminant information within slowly proliferating liver lesions.

CONCLUSION

Tumor-cell proliferation of liver lesions should be used with stage of the primary colorectal cancer for a more accurate prognosis in patients submitted to curative hepatic resection.

Cell proliferation as a predictor of response to chemotherapy in metastatic breast cancer: a prospective study

Many biologic prognostic markers are available for patients with breast cancer, and considerable interest has been devoted to confirm preliminary evidence of their role as indicators of treatment response. It remains to be assessed whether such markers are predictors of response only to first-line or also to successive therapies. Proliferative activity, defined by the 3H-thymidine labeling index (TLI), was determined on the primary lesion from 76 patients at time of first diagnosis. At relapse, patients underwent chemotherapy as absolute (48 cases) or relative (28 cases) first-line treatment, and their clinical response was analyzed in relation to the TLI of the primary lesion. The objective clinical response was significantly higher for rapidly (47%; CL, 33-61%) than for slowly proliferating tumors (15%; CL, 1-29%). These findings held true also when adjusted for metastatic site, previous treatment, chemotherapy regimen administered, and hormone receptor status. However, the direct relation between cell proliferation and benefit from chemotherapy held true only when such a treatment was used as an absolute first-line approach. Cell proliferation of primary lesions represents a consistent indicator of response to chemotherapy over time. Previously administered regimens, at least hormone therapy, could alter the proliferation-related chemosensitivity profile of individual tumors.

Cell proliferation in 3,800 node-negative breast cancers: consistency over time of biological and clinical information provided by 3H-thymidine labelling index

For breast cancer, many prognostic markers that initially appeared promising have failed to maintain their clinical predictive value. Few reports have analyzed the consistency over time of biological and clinical information provided by biomarkers. Tumour cell proliferation has acquired relevance as an indicator of prognosis and of response to treatment. Since its clinical role has been investigated for some decades, cell proliferation represents an ideal marker for an over-time validation. In 3,800 node-negative breast cancers recruited between 1972 and 1991, the consistency of information provided by the 3H-thymidine labelling index (TLI), in terms of basic relations with other clinico-pathological and biological variables and clinical predictivity, was evaluated using a combined analysis of results previously published by our group for distinct series of patients. Clinical predictivity was analyzed on a subset of 2,067 patients given local-regional therapy until relapse and followed for a median time from 6 to 10 years. Over the entire period TLI maintained a weak direct relation with tumour size and an inverse strong relation with steroid receptors. An increase in TLI was observed for tumours in post-menopausal patients up to the mid 1980s. During 3 different accrual periods (1972-1983; 1984-1987; 1988-1991), TLI was a consistent and independent predictor of relapse-free time, distant metastasis and overall survival, regardless of its consideration as a continuous variable or with a cutoff value of 3%. The reproducibility of our results over time provides support to the consistency of the methodology used and of the biological and clinical information obtained when using TLI as an indicator of breast cancer cell proliferation.

Expression of high-affinity 67-kDa laminin receptors in primary breast cancers and metachronous metastatic lesions or contralateral cancers

The presence of high-affinity 67-kDa laminin receptors, detected immunohistochemically, was determined on 63 primary breast cancers and on metachronous metastatic lesions or contralateral cancers from the same patients. A disagreement was observed in two-thirds of the cases. In particular, laminin receptor content was significantly lower (P = 0.02) in local recurrences and slightly higher in lymph node metastasis than in the corresponding primary tumours.

MIB-1 and S-phase cell fraction predict survival in non-Hodgkin's lymphomas

The monoclonal antibody anti-Ki67 is used to detect proliferating cells, but its main limitation is the requirement of fresh-frozen material. On a series of patients with non-Hodgkin's lymphoma, we used a Ki67 equivalent monoclonal antibody, the recently proposed MIB-1, on formalin-fixed histopathological material using microwave antigen retrieval. MIB-1 expression was analysed in relation to other proliferation indices, such as autoradiographic H-thymidine labelling index (HTL1) and flow cytometric S-phase cell fraction (FCM-S) and to pathological status. Moreover, the prognostic relevance of the cell kinetic indices was defined in uni- and multivariate analyses including histology and tumour stage. The relationship between MIB-1 index and the other proliferation indices was statistically significant even though the correlation coefficient was around 0.6. The MIB-1 index was also related to the REAL (Revised European American Lymphoma) classification, but not to the Ann Arbor stage classification. Univariate analysis showed that the MIB-1 index was a significant predictor of 6-year survival in the overall series and in distinctly analysed low-grade and high-grade lymphoma subgroups. With regard to S-phase indices, HTLI was a powerful prognosticator in patients with high-grade histologies and FCM-S in patients with low-grade histologies. Multivariate analyses revealed that MIB-1 index, HTLI and FCM-S retained their prognostic significance independent of histology. In conclusion, the MIB-1 antibody provides prognostic information in non-Hodgkin's lymphomas and has the main advantage that it can be used in formalin-fixed, paraffin-embedded specimens.

Modulation by lonidamine on the combined activity of cisplatin and epidoxorubicin in human breast cancer cells

The ability of lonidamine (LND), an energolytic derivative of indazole-carboxylic acid, to modulate the cytotoxic activity of cisplatin (CDDP) and epidoxorubicin (EPI), singly or in combination, was investigated in two human breast cancer cell lines (MCF7 and T47D). A 72-hr post-incubation with a non-cytotoxic concentration of LND (75 microM) increased the activity of a 1-hr CDDP treatment as well as that of a 1 to 16-hr EPI treatment. A different pattern of interaction among the drugs and modulator was observed as a function of the sequence of drug treatment. Specifically, supra-additive or additive effects of the combination were obtained in the two cell lines according to the different treatment schemes. In particular, the maximum potentiation was observed in MCF7 cells simultaneously exposed to CDDP, EPI and LND for 1 hr and then post-incubated with LND for 72 hr, and in T47 first exposed to EPI and LND, then to CDDP and LND, and finally post-incubated with LND. Flow cytometric analysis of MCF7 cell distribution in the different cycle phases showed that combined treatment with EPI/CDDP/LND was able to stabilize cell cycle perturbations (mainly G2M accumulation) induced by individual agents. The ability of LND to potentiate CDDP and EPI cytotoxicity, and the consideration that LND causes side effects different from those caused by alkylating agents and anthracyclines, make this compound an attractive candidate for multidrug combination therapy in breast cancer.

Biological predictors of response to radiotherapy in cervical carcinomas

On 21 patients with T1b-T3b tumours subjected to external radiotherapy and brachytherapy, the expression of P53 and glutathione S-transferase pi [GST-pi], immunohistochemically detected, the S-phase cells fraction (H-3-thymidine labeling index, TLI) and DNA content evaluated by image analysis were determined on biopsies before and after the first 10 Gy. P53 accumulation was reduced in 60% of P53-overexpressing tumours and not induced in P53-negative tumours, GST-pi was induced in about 40% of pretreatment GST-pi-negative cases, TLI was reduced in 70% of the cases regardless of pretreatment values, and DNA profiles remained unchanged in two-thirds of the cases. P53 accumulation was a predictor of 3-year relapse-free survival after radiotherapy, followed by GST-pi expression, whereas TLI did not influence prognosis.

Effect of melphalan and hyperthermia on p34cdc2 kinase activity in human melanoma cells

We previously reported that combined treatment with melphalan and mild hyperthermia (1 h at 42 degrees C) caused a synergistic cytotoxic effect in JR8 melanoma cells, paralleled by a stabilisation of a melphalan-induced G2-phase cell block. In this study, we investigated the effect of melphalan and hyperthermia on proteins that regulate G2-M transition. Neither hyperthermia nor melphalan at a concentration of 2.5 micrograms ml-1, which had no antiproliferative effect at 37 degrees C, interfered with cyclin B1 expression or p34cdc2 kinase activity. At a concentration of 8.5 micrograms ml-1, which reduced cell growth by 50% at 37 degrees C, melphalan inhibited p34cdc2 kinase activity as a consequence of an increased tyrosine phosphorylation of the protein. A similar inhibitory effect on p34cdc2 kinase was obtained when the lowest melphalan concentration (2.5 micrograms ml-1) was used under hyperthermic conditions. Our results indicate that thermal enhancement of melphalan cytotoxicity could be mediated at least in part by an inhibition of p34cdc2 kinase activity, which prevents cell progression into mitosis.