New strategies for medical management of castration-resistant prostate cancer.

Although advanced prostate cancer patients respond very well to front-line androgen deprivation, failure to hormonal therapy most often occurs after a median time of 18-24 months. The care of castration-resistant prostate cancer (CRPC) has significantly evolved over the past decade, with the onset of first-line therapy with docetaxel. Although numerous therapy schedules have been investigated alongside docetaxel, in either first-line or salvage therapy, results were dismal. However, CRPC chemotherapy is currently evolving, with, on the one hand, new agents targeting androgen metabolism and, on the other hand, significant progress in chemotherapy drugs, particularly for second-line therapy. The aim of the present review is to describe the current treatments for CRPC chemotherapy alongside their challengers that might shortly become new standards. In this article, we discuss the most recent data from clinical trials to provide the reader with a comprehensive, state-of-the-art overview of CRPC chemotherapy and hormonal therapy.

Identification of novel truncated androgen receptor (AR) mutants including unreported pre-mRNA splicing variants in the 22Rv1 hormone-refractory prostate cancer (PCa) cell line.

Advanced prostate cancer (PCa) has emerged as a public health concern due to population aging. Although androgen deprivation has proven efficacy in this condition, most advanced PCa patients will have to face failure of androgen deprivation as a treatment. Mutations in the androgen receptor (AR) from tumor cells have been shown to induce androgen independency both in PCa cell lines and in the clinic. We have investigated the molecular events leading to androgen independency in the 22Rv1 cell line, a commonly used preclinical model of PCa. Besides AR mutants that have been described so far, including nonsense mutations, recent data have focused on AR pre-mRNA aberrant splicing as a new mechanism leading to constitutively active truncated AR variants. In this article, we describe two novel variants arising from aberrant splicing of AR pre-mRNA, characterized by long mRNA transcripts that encode truncated, constitutively active proteins. We also describe several new nonsense mutants that share ligand independency and transcriptional activity. Finally, we show that alongside these mutants, 22Rv1 cells also express a mutant AR lacking exon 3 tandem duplication, a major feature of this cell line. By describing unreported AR mutants in the 22Rv1 cell line, our data emphasize the complexity and heterogeneity of molecular events that occur in preclinical models, and supposedly in the clinic. Future work on the 22Rv1 cell line should take into account the concomitant expression of various AR mutants.

A V530I Mutation in c-KIT Exon 10 Is Associated to Imatinib Response in Extraabdominal Aggressive Fibromatosis.

Aggressive fibromatosis (AF) or desmoid tumor is a rare condition, characterized by deep tissue invasion by a monoclonal fibroblastic neoplasm, developed from musculoaponeurotic structures. Surgery is the treatment of choice, but negative margins can hardly been achieved in large tumors, and can lead to major functional disability. AF medical therapy includes nonsteroids anti-inflammatory drugs, tamoxifen, with inconsistent results. Several reports of imatinib efficacy in AF appear in the literature. Here, we describe for the first time a V530I KIT exon 10 mutant that was associated to a dramatic imatinib response in an extraabdominal aggressive fibromatosis. The previously discovered V530I substitution was characterized in the core binding factor AML, but had never been reported in any other condition, so far. In this paper, we discuss the KIT exon 10 mutations or polymorphisms that have been described in a variety of KIT-related conditions, including acute myelogenous leukemia, mastocytosis, and aggressive fibromatosis.

Pleiotropic functional properties of androgen receptor mutants in prostate cancer.

The androgen receptor (AR) signaling pathway plays an important role during the development of the normal prostate gland, but also during the progression of prostate cancer on androgen ablation therapy. Mutations in the AR gene emerge to keep active the AR signaling pathway and to support prostate cancer cells growth and survival despite the low levels of circulating androgens. Indeed, mutations affecting the ligand binding domain (LBD) of the AR have been shown to generate so-called "promiscuous" receptors that present widened ligand specificity and allow the stimulation of these receptors by a larger spectrum of endogenous hormones. Another class of mutations, arising in the amino-terminal domain (NTD) of the receptor, modulate AR interactions with coregulators involved in cell proliferation regulation. Besides characteristics of these well-known types of mutations, the properties of other classes of AR mutants recently described in prostate cancer are currently under investigation. Most interestingly, in addition to their potential role in the mechanisms which allow prostate cancer cells to escape androgen ablation therapy, data suggest that certain AR mutations are present early in the natural history of the disease and may play a role in many aspects of prostate cancer progression. Surprisingly, singular truncated AR devoid of their carboxy-terminal end (CTE) region seem to exert specific paracrine effects and to induce a clonal cooperation with neighboring prostate cancer cells, which may facilitate both the invasion and metastasis processes. In this article, we review the functional properties of different classes of AR mutants and their potential impact on the natural history of prostate cancer. Hum Mutat 0, 1-14, 2008. (c) 2008 Wiley-Liss, Inc.

Paralytic ileus possibly associated with interaction between ritonavir/lopinavir and vincristine.

CASE DESCRIPTION: A French Caucasian man aged 39 with HIV infection was treated with abacavir/lamivudine and ritonavir/lopinavir. The patient (normal renal and liver functions) was diagnosed with a Burkitt lymphoma for which he was treated with cyclophosphamide day 1 to 5; doxorubicin day 1; methotrexate day 10; and vincristine day 1 and 8. At day 12, he suffered from abdominal pain associated with constipation. Paralytic ileus was diagnosed by study imaging. Ileus lasted 10 days necessitating parenteral feeding. Later on, a further cycle of chemotherapy with etoposide replacing vincristine was given and was well tolerated. CONCLUSION: We speculate that an interaction between ritonavir/lopinavir and vincristine was responsible for this severe toxicity. Vincristine is transported by P-gp and is metabolized via CYP3A5. Ritonavir is a potent CYP3A5 isoenzyme and P-gp inhibitor. Lopinavir is also a P-gp inhibitor. Ritonavir and lopinavir might have delayed vincristine elimination. Clinicians should be aware of this possible interaction.

Factors associated with overall and attributable mortality in invasive aspergillosis.

BACKGROUND: Invasive aspergillosis is associated with high death rates. Factors associated with increased mortality have not yet been identified in a large population of patients with various underlying conditions. METHODS: We retrospectively reviewed 385 cases of suspected or documented aspergillosis that occurred during a 9-year period. We identified 289 episodes that fulfilled the criteria for possible, probable, or proven invasive aspergillosis according to the international definition criteria and that was treated with an anti-Aspergillus active antifungal drug. Clinical and microbiological variables were analyzed for their effects on overall and attributable mortality. Significant variables in univariate analysis were introduced into a multivariate Cox model. RESULTS: Twelve-week overall and disease-specific survival rates were 52.2% (95% confidence interval, 46.5%-57.9%) and 59.8% (95% confidence interval, 54.0%-65.4%), respectively. Receipt of allogeneic hematopoietic stem cell or solid-organ transplant, progression of underlying malignancy, prior respiratory disease, receipt of corticosteroid therapy, renal impairment, low monocyte counts, disseminated aspergillosis, diffuse pulmonary lesions, pleural effusion, and proven or probable (as opposed to possible) aspergillosis are predictors of increased overall mortality. Similar factors are also predictors of increased attributable mortality, with the following exceptions: pleural effusion and low monocyte counts have no impact, whereas neutropenia is associated with a higher attributable mortality. CONCLUSIONS: Identification of predictors of death helps in the identification of patients who could benefit from more-aggressive therapeutic strategies. Initiation of therapy at the stage of possible infection improves outcome, and this finding calls for the development of efficient preemptive strategies to fill the gap between empirical and directed therapy.

Effect of pO2 on antitumor drug cytotoxicity on MDR and non-MDR variants selected from the LoVo metastatic colon carcinoma cell line.

Two chemosensitive cell lines, LoVo-fusoid (LoVo-f) and LoVo-small cells (LoVo-sc) were derived from the original LoVo cell line. These two variants and the multidrug-resistant (MDR) cell line LoVo-Dox were screened for various properties. In non-permeabilized cells, only LoVo-sc showed mucin-2 staining whereas labelling was positive in all permeabilized cell lines. As shown by electron microscopy screening and by relative resistance to trypsin detachment, only LoVo-sc cells showed strong mucus secretion. All three cell lines displayed strong staining for P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP) and lung-resistance-related protein (LRP) in different locations according to the drug resistance state. The three cell lines showed intracellular labelling of LRP and MRP. The sensitive cells showed P-gp in a large perinuclear ring and in the cytoplasm, but little (LoVo-sc cells) or no staining (LoVo-f cells) was shown at the plasma membrane level. For the Lovo-Dox cells, P-gp was located in the plasma membrane, in cellular anchorages and in the cytoplasm as well. Cell resistance against antineoplastic agents often results from mobilization of various factors, the modulation of which is linked to the culture conditions. As most of the protocols utilize cells growing in (air + 5-10% CO2) atmosphere e.g. 20% O2, balance of the respective participants in the MDR multi-modal mechanism may not be representative of the in vivo situation and may lead to erratic pharmacological response. Indeed, cells within solid tumours were exposed to low pO2, most of them being under hypoxic condition (0.1-5% O2). In the absence of anticancer drugs, all LoVo cell lines grew notably faster at 20% O2 than at 5% O2. Moreover, respective sensitivities of both non-MDR variants to doxorubicin were altered according the pO2. Whatever the pO2 was, virtually none of the antioxidants tested affected the cytotoxic activity of doxorubicin for the three cell lines. By contrast, trolox showed a strong inhibitory effect on doxorubicin activity. These results underline the importance of evaluating the role of hypoxia on the cytotoxic effect of chemotherapeutic agents used either as single drugs or in combination therapy.

Adriamycin, cisplatin, ifosfamide and paclitaxel combination as front-line chemotherapy for locally advanced and metastatic angiosarcoma. Analysis of three case reports and review of the literature.

Angiosarcoma represents 1 to 2% of soft tissue tumors. It originates from endothelial cells of small blood vessels and may affect a variety of organs, including the retroperitoneum, skeletal muscle, subcutis, liver, heart and breast. The outcome of angiosarcoma is poor for those patients in whom aggressive surgery cannot be considered. Chemotherapy, generally consisting of the combination of anthracyclines and ifosfamide, has little, but consistent effect. We report three cases of angiosarcoma in which first-line chemotherapy with adriamycin 40 mg/m2 day 1, ifosfamide 3 g/m2 day 1-2, cisplatin 35 mg/m2 day 1-2 and paclitaxel 175 mg/m2 day 3 led to clinically meaningful responses. The clinical relevance of incorporating paclitaxel in conventional soft tissue chemotherapy schedules in the light of both literature data and our experience is discussed. We emphasize the need for designing trials specifically dedicated to angiosarcomas, as this rare and severe condition may be a target for new antiangiogenic drugs.

Specific properties of a C-terminal truncated androgen receptor detected in hormone refractory prostate cancer.

Mutations in the human androgen receptor (AR) gene that lead to C-terminus truncated AR variants are frequently detected in prostate cancer (PC). These AR variants lack both the ligand-binding domain (LBD) and the AF-2 region. The aim of this study was to delineate the alternative mechanisms that lead to the activation of such AR variants as they are unresponsive to hormone stimulation, and to outline consequences of the loss of the LBD/AF-2 region on their functional properties. By using an MMTV-luciferase reporter construct and LY294002, UO126, or ZD1839, inhibitor of PI3K, MEK1/2, and EGFR signaling pathway respectively, we demonstrated that phosphorylation was required for full transcriptional activities of one these AR variants, the Q640X mutant AR. Western-blot analyses confirmed that these inhibitors affect the phosphorylation status of this AR variant. Furthermore, studies of the intranuclear colocalization of the Q640X AR with cofactors, such as CBP, GRIP-1, and c-Jun, reveal that the transcriptional complex that forms around the mutant AR is different to that formed around the wild type AR. We demonstrated that CBP and c-Jun are highly recruited by the mutant AR, and this leads to an unexpected activation of AP-1, NFAT, and NFkappaB transcriptional activities. Similar enhanced activities of these transcription factors were not observed with the wild type AR. The importance of the LBD/AF-2 for the regulation of AR transcriptional activities, the impact of the presence of such AR variants on PC cells proliferation and survival, and on progression to androgen independence are discussed.

A splicing variant of the androgen receptor detected in a metastatic prostate cancer exhibits exclusively cytoplasmic actions.

The androgen receptor (AR) is a ligand-activated transcription factor that displays genomic actions characterized by binding to androgen-response elements in the promoter of target genes as well as nongenomic actions that do not require nuclear translocation and DNA binding. In this study, we report exclusive cytoplasmic actions of a splicing variant of the AR detected in a metastatic prostate cancer. This AR variant, named AR23, results from an aberrant splicing of intron 2, wherein the last 69 nucleotides of the intronic sequence are retained, leading to the insertion of 23 amino acids between the two zinc fingers in the DNA-binding domain. We show that the nuclear entry of AR23 upon dihydrotestosterone (DHT) stimulation is impaired. Alternatively, DHT-activated AR23 forms cytoplasmic and perinuclear aggregates that partially colocalize with the endoplasmic reticulum and are devoid of genomic actions. However, in LNCaP cells, this cytoplasmic DHT-activated AR23 remains partially active as evidenced by the activation of transcription from androgen-responsive promoters, the stimulation of NF-kappaB transcriptional activity and by the decrease of AP-1 transcriptional activity. Our data reveal novel cytoplasmic actions for this splicing AR variant, suggesting a contribution in prostate cancer progression.

The cytotoxicity of high-linear energy transfer radiation is reinforced by oxaliplatin in human glioblastoma cells.

The combination of high-linear energy transfer (LET) radiation with chemotherapeutic agents may offer new perspectives in cancer treatment. We therefore assessed the consequences of a treatment in which U-87 human glioblastoma cells were irradiated with p(65)+Be neutrons in the presence of oxaliplatin, a third generation platinum anticancer drug having higher apoptosis-inducing activity than cisplatin. Cell survival, apoptosis, cell cycle progression as well as p21 and p53 protein expressions were analyzed. Results show that an enhanced cytotoxic effect was obtained when the two treatments were combined and that, unlike what we previously observed with cisplatin, this was not due to a reinforcement of apoptosis. Altogether, our results also indicate the potential of oxaliplatin for use in association with high-LET radiation against tumors refractory to conventional photon radiotherapy.

[Aromatase inhibitors in the adjuvant treatment of early breast cancer. Is there still a place for tamoxifen?]. / Place actuelle des inhibiteurs de l'aromatase dans le traitement adjuvant des cancers du sein. Reste-t-il des indications aux anti-oestrogènes de type tamoxifène?

Adjuvant hormone therapy is indicated only in patients whose tumors express estrogen or progesterone receptors. Aromatase inhibitors (AI) are indicated only in postmenopausal patients. AI are significantly more effective than tamoxifen in terms of disease-free survival and distant recurrence-free survival; these advantages will probably result in a significant overall survival benefit after sufficient follow-up. This benefit justifies the use of AI in all postmenopausal patients in the absence of contraindications and after complete explanations of the benefit/risk ratio and potential side effects of this treatment. The benefit of AI over tamoxifen may be particularly pronounced for tumors overexpressing HER-2 and perhaps for ER+PR- tumors. Replacement of tamoxifen by AI or first-line treatment with AI is advised in patients with such tumors. Extended adjuvant treatment with AI for 5 years significantly increases survival among patients already treated with tamoxifen for 5 years; it also provides a significant overall survival benefit to patients with positive axillary nodes and should be used in this group. AI may cause several generally mild side effects, including insomnia, arthralgia, bone loss, vaginal dryness, dyspareunia and loss of libido. Tamoxifen may be appropriate for well-informed patients with these side effects, especially those with RE+ RP+ tumors and a low risk of thromboembolic or endometrial complications. The effects of AI on memory and cognition should also be investigated thoroughly before its long-term use, especially in the elderly.

Potentiation of apple procyanidin-triggered apoptosis by the polyamine oxidase inactivator MDL 72527 in human colon cancer-derived metastatic cells.

Apple procyanidins have chemopreventive properties in a model of colon cancer, they affect intracellular signalling pathways, and trigger apoptosis in a human adenocarcinoma-derived metastatic cell line (SW620). In the present study we investigated relationships between procyanidin-induced alterations in polyamine metabolism and apoptotic effects. Apple procyanidins diminish the activities of ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase, key enzymes of polyamine biosynthesis, and they induce spermidine/spermine N(1)-acetyltransferase, which initiates retroconversion of poly-amines. As a consequence of the enzymatic changes polyamine concentrations are diminished, and N(1)-acetyl-polyamines accumulate in SW620 cells. In contrast with expectations MDL 72527, an inactivator of polyamine oxidase (PAO), improved the anti-proliferative effect of procyanidins, and caused an increase of the proportion of apoptotic cells, although it prevented the formation of hydrogen peroxide and 3-acetamidopropanal, the cytotoxic products of PAO-catalysed degradation of N(1)-acetylspermidine and N1-acetylspermine. Addition of 500 microM N1-acetylspermidine to the culture medium in the presence of procyanidins mimicked the effect of MDL 72527. Therefore we presume that the enhanced procyanidin-triggered apoptosis by MDL 72527 is mediated by the accumulation of N(1)-acetyl-polyamines. The observation that apple procyanidins enhance polyamine catabolism and reduce polyamine biosynthesis activity similar to known inducers of SSAT, without sharing their toxicity, and the potentiation of these effects by low concentrations of MDL 72527 suggests apple procyanidins for chemopreventive and therapeutic interventions.

Cell death induced in a human glioblastoma cell line by p(65)+Be neutrons combined with cisplatin.

High linear energy transfer (LET) radiation have the ability to kill cancer cells resistant to conventional radiotherapy. On the other hand, protocols combining radiotherapy and chemotherapy are effective in eradicating certain inoperable cancers. In this study, we investigated the cytotoxicity of a co-treatment with fast neutrons and cisplatin in a human glioblastoma cell line, U-87. Cells cultured in vitro were irradiated with p(65)+Be neutrons in the presence of cisplatin. Cell survival and the induction of apoptosis and premature senescence were assessed at different time intervals thereafter, using a variety of methods. A marked reinforcement of the cytotoxicity was obtained when irradiation and cisplatin were associated. This reflected both an amplification of the apoptotic process and the induction of premature cell senescence. The efficiency of a combination between fast neutrons and cisplatin in inducing cell death in U-87 is more than additive. The present data concur with those we previously reported in a mouse lymphoma and suggest the potential utility of platinum compounds as adjuncts to future cancer therapy protocols using high-LET radiation.

Aspergillus galactomannan detection in the diagnosis of invasive aspergillosis in cancer patients.

PURPOSE: To assess the Aspergillus galactomannan enzyme-linked immunosorbent assay (ELISA) in the diagnosis of invasive aspergillosis (IA) in adult and pediatric oncohematologic patients. PATIENTS AND METHODS: The study was conducted in four patient groups: those with fever of unknown origin (FUO) during neutropenia, suspected pulmonary infection (PI), or nonpulmonary aspergillosis (NPA) and those undergoing surveillance (S) after hematopoietic stem-cell transplantation (HSCT). IA was classified as definite, probable, or possible, according to European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions. RESULTS: A total of 3,294 serum samples were collected during 797 episodes (FUO, 261; PI, 297; NPA, 28; and surveillance, 211), and 153 episodes of IA were diagnosed (31 definite, 67 probable, and 55 possible). Three episodes were first suspected from galactomannan ELISA; the remaining 150 cases were diagnosed from clinical or radiologic evidence. Sensitivity of the ELISA was 64.5%, 16.4%, and 25.5% in definite, probable, and possible episodes of IA, respectively, and was lower in patients positive for anti-Aspergillus antibodies than in antibody-negative patients. Most false-positive results occurred in children and in allogeneic HSCT (allo-HSCT) patients. Overall specificity of the ELISA was 94.8%. It was lower in children compared with adults (P <.0001) and in allo-HSCT patients compared with non-allo-HSCT adults (P =.0002). Lowering the ELISA cutoff value from 1.500 to 0.700 seemed more relevant for non-allo-HSCT adults (sensitivity, 73.1%, 44.3%, and 44.7% in definite, probable, and possible IA, respectively; specificity, 94%). CONCLUSION: Galactomannan ELISA seems less sensitive than previously described, and sensitivity can be further reduced by the presence of anti-Aspergillus antibodies. A new cutoff value for the ELISA of 0.700 is proposed for non-allo-HSCT adults.

Signal transduction pathways of taxanes-induced apoptosis.

Docetaxel (Taxotere) is a member of the taxane class of anticancer agents to reach clinical use. This semisynthetic analog of paclitaxel (Taxol) is one of the newer potent anti-neoplastic agents now undergoing extensive laboratory and clinical investigations. Several studies indicate that antimicrotubule agents are potent promoters of apoptosis in cancer cells. Cytotoxic mechanisms of antimitotic taxoids are not yet fully understood, but it has been demonstrated that docetaxel increases tubulin polymerisation, promotes microtubule assembly and also inhibits tubulin depolymerisation. Disruption of microtubules results also in the induction of tumor suppressor gene p53 and inhibitor of cyclin-dependent kinases and activation/inactivation of several protein kinases. As a consequence cells are arrested in the G2-M phase of the cell cycle, after which they may either undergo cell death by apoptosis or necrosis or overcome the G2-M stop and continue in the division cycle (often toward a post-mitotic cell death) depending on the tumor cell type. Nevertheless, how docetaxel induces apoptotic cell death or caspases activation is not yet defined. One may assume that taxanes are able to induce the phosphorylation of Bcl-X(L)/Bcl-2 members and thus inactivate their anti-apoptotic capacities. The down-regulation of Bcl-2 and/or the upregulation of p53 and p21/WAF-1 are certainly one of the important modes of apoptosis induction by taxanes. The aim of this framework is to summarize the effects of microtubuline targeting agents on apoptotic signal transduction and new molecular pathways. Finally, we will also discuss the potential therapeutic interest in the association of docetaxel and ionizing radiation.

A yeast-based functional assay for the detection of the mutant androgen receptor in prostate cancer.

OBJECTIVE: Mutations in the ligand-binding domain of the human androgen receptor (AR) figure among the ways used by prostate adenocarcinoma (PCa) cells to escape androgen dependence. These mutations may broaden the specificity and/or affinity of the AR to other hormones, resulting in inappropriate receptor activation and thus affecting the PCa response to physiological stimuli and hormonal therapies. DESIGN: In order to clarify the impact of these mutations on disease progression and treatment, we have developed a yeast-based functional assay that allows the detection of mutant ARs and the analysis of their transactivation capacities in response to different ligands. METHODS: AR cDNA was directly cloned into an expression vector in a yeast strain that carries a reporter gene (ADE2) linked to an androgen-dependent promoter. The expression of the ADE2 gene and consequently the yeast cell growth in a selective medium depleted in adenine depends on the specificity of the AR for the ligand added to the medium. RESULTS: By analysing the transactivation capacities of different AR molecules in response to a broad range of steroid and non-steroid ligands, we have demonstrated that this assay can discriminate among wild-type AR, T877A, C685Y and L701H mutant ARs and that at least 1% of mutant ARs could be detected when mutant and wild-type ARs were mixed at the cDNA level. CONCLUSIONS: The data presented here show that this simple AR assay is convenient for the routine detection of mutant ARs in PCa and is also suitable to evaluate the antagonist activities of anti-androgen molecules.

Gastrointestinal stromal tumor in an XYY/XY male.

A 32-year-old patient was diagnosed with a gastrointestinal stromal tumor of the small bowel. The pathologic diagnosis was confirmed by positive immunochemistry against CD34, and against CD117, the tyrosine-kinase c-kit. We performed a karyotypic analysis on the basis of the patient's tall stature and speech difficulties. One hundred thirty-two metaphases were obtained on PHA-stimulated peripheral blood; 123 of them presented an extra chromosome Y. Fluorescence in situ hybridization using a Y satellite III probe showed the presence of a sole copy of chromosome Y in the tumor cells precluding a direct relationship between the extra chromosome Y and the initiation of the tumor. This is, to our knowledge, the second occurrence of a nonhematologic malignancy reported in this genetic disorder. A review of the malignancies observed in men with the XYY constitution is presented.

Sensitivity to cisplatin treatment of human K1 thyroid carcinoma cell lines with altered p53 function.

AIM: p53 is the most frequently altered gene in human cancer. It was expected to be the principle marker for chemo/radiosensitivity, resistance, tumor recurrence and ultimate survival, but is no longer considered a universal prognostic factor. Different alterations in the p53 gene have led to conflicting results depending on cell/tissue specificities and on radiation and drug specificities. METHODS: We evaluated the properties of isogenic and isophenotypic cell lines from the K1 papillary thyroid carcinoma in which p53 function was disrupted either by mutation (expression of dominant-negative p53, 143(ala)) or by inactivation (expression of human papilloma virus protein HPV16 E6). Their proliferation, their propensity to trigger apoptosis and their survival were analyzed after treatment with cisplatin (CDDP). RESULTS: Only K1 lines with wild-type p53 had significantly accumulated apoptotic bodies 72 h after treatment. Despite their incapacity to trigger apoptosis in response to CDDP treatment, the survival of K1 cell lines in which p53 expression was altered was not significantly different from the survival of K1 cell lines expressing wild-type p53. In addition, the order of magnitude of resistance of K1 cells in which p53 was mutated was similar to that in which p53 was totally inactivated, although the pathways involved may be different. CONCLUSIONS: These results show that the means by which p53 expression is disrupted and the consequence on downstream pathways regulated by p53 deserve to be considered in order to elucidate some apparently conflicting responses of this gene.