Spatiotemporal activation of caspase-dependent and -independent pathways in staurosporine-induced apoptosis of p53wt and p53mt human cervical carcinoma cells.

International audienceBACKGROUND INFORMATION: Caspase-dependent and -independent death mechanisms are involved in apoptosis in a variety of human carcinoma cells treated with antineoplastic compounds. Our laboratory has reported that p53 is a key contributor of mitochondrial apoptosis in cervical carcinoma cells after staurosporine exposure. However, higher mitochondrial membrane potential dissipation and greater DNA fragmentation were observed in p53wt (wild-type p53) HeLa cells compared with p53mt (mutated p53) C-33A cells. Here, we have studied events linked to the mitochondrial apoptotic pathway. RESULTS: Staurosporine can induce death of HeLa cells via a cytochrome c/caspase-9/caspase-3 mitochondrial-dependent apoptotic pathway and via a delayed caspase-independent pathway. In contrast with p53wt cells, p53mt C-33A cells exhibit firstly caspase-8 activation leading to caspase-3 activation and Bid cleavage followed by cytochrome c release. Attenuation of PARP-1 [poly(ADP-ribose) polymerase-1] cleavage as well as oligonucleosomal DNA fragmentation in the presence of z-VAD-fmk points toward a major involvement of a caspase-dependent pathway in staurosporine-induced apoptosis in p53wt HeLa cells, which is not the case in p53mt C-33A cells. Meanwhile, the use of 3-aminobenzamide, a PARP-1 inhibitor known to prevent AIF (apoptosis-inducing factor) release, significantly decreases staurosporine-induced death in these p53mt carcinoma cells, suggesting a preferential implication of caspase-independent apoptosis. On the other hand, we show that p53, whose activity is modulated by pifithrin-alpha, isolated as a suppressor of p53-mediated transactivation, or by PRIMA-1 (p53 reactivation and induction of massive apoptosis), that reactivates mutant p53, causes cytochrome c release as well as mitochondrio-nuclear AIF translocation in staurosporine-induced apoptosis of cervical carcinoma cells. CONCLUSIONS: The present paper highlights that staurosporine engages the intrinsic mitochondrial apoptotic pathway via caspase-8 or caspase-9 signalling cascades and via caspase-independent cell death, as well as through p53 activity

Sodium butyrate with UCN-01 has marked antitumour activity against cervical cancer cells.

International audienceUCN-01 was shown to be a potentiator of NaB therapy for cervical cancer cells

Tumoral lymphocyte immune response to preoperative radiotherapy in locally advanced rectal cancer as a prognostic factor for survival: the LYMPHOREC study

Présentation PosterInternational audienceBackground: Short-course preoperative radiotherapy (sc-preopRT) and long-course preoperative radiotherapy (lc-preopRT) followed by total mesorectal excision (TME) are worldwide standards of care in locally advanced T3–4 N0 or N1 rectal adenocarcinoma. It is now well established that the host immune system participates in the elimination of tumor cells and that significant tumor infiltration by T-cells (LT), such as CD8+, is associated with a better prognosis. In colorectal tumors, the infiltration of Treg FoxP3+ is also described as a prognostic factor associated with better survival. We aimed to investigate the impact of the immune response to preoperative RT on progression-free survival (PFS) and overall survival (OS) in rectal cancer managed with TME.Material and Methods: We analyzed data for 237 patients with rectal cancer who underwent TME between 1995 and 2007 after neo-adjuvant treatment with preoperative RT with or without CT in 3 French centers. The LYMPHOREC study was approved by the French national review boards and independent ethics committee (CPP, CCTIRS and the CNIL). Our primary objective was to assess the impact of the immune infiltration of the tumor or tumor site (in cases with complete response) by CD8+ and FoxP3+ lymphocytes after sc-preopRT or lc-preopRT with or without CT on progression-free survival (PFS) and overall survival (OS). Our secondary objectives were to assess changes in the quantities of these lymphocyte infiltrations with respect to the type of preoperative RT (with vs without chemotherapy) or the dose fractionation scheme (≤2Gy vs >2Gy/fraction). These second analyses were performed with 133 patients from whom one biopsy sample was collected. A biopsy-based pretherapeutic lymphocyte infiltration was thus evaluated.Results: In univariate analysis, TNM stage, the delay between surgery and RT, CD8+, FoxP3+ and the ratio CD8+/FoxP3+ were significantly correlated with survival outcomes while chemotherapy as a component of preoperative radiotherapy was not. In multivariate analysis, when adjusted for clinical and treatment-related variables, tumor infiltration by FoxP3 lymphocytes after treatment significantly correlated with PFS (p=0.007). Variations in the CD8/FoxP3 ratio inside the epithelial tissue from before to after preoperative RT correlated with PFS and OS (p=0.049 and p=0.024, respectively). Interestingly, the dose per fraction (<2Gy vs. ≥2Gy) significantly influenced the CD8/FoxP3 ratio after treatment (p=0.027) with a lower ratio with hypofractionated RT.Conclusions: Patients with rectal cancer who had a significant decrease in the CD8/FoxP3 ratio after preoperative radiotherapy had better survival outcomes. The CD8/FoxP3 ratio needs to be validated prospectively. The immune response to preoperative RT may guide physicians in the decision to give adjuvant treatment to patients with rectal cancer