Retrospective analysis of the role of cyclin E1 overexpression as a predictive marker for the efficacy of bevacizumab in platinum-sensitive recurrent ovarian cancer.

The relative benefit of bevacizumab in ovarian cancer (OC) patients is greater the more the disease becomes platinum-resistant. Among other mechanisms of action, antiangiogenic agents may induce homologous recombination deficiency. Cyclin E1 (CCNE1) overexpression is a proposed marker of platinum resistance and is mutually exclusive with deficiency in homologous recombination. In this study, we evaluated the predictive value of CCNE1 expression with regard to the efficacy of bevacizumab. We retrospectively evaluated data from patients with platinum-sensitive recurrent OC who were treated with chemotherapy (CT) plus bevacizumab (Bev group) or CT alone (CT group) at a tertiary cancer centre from 2005 to 2017. The two groups were paired according to histology, platinum-free interval (PFI) and number of previous treatment lines. Progression-free survival (PFS) was compared between groups by log rank test and Cox regression. A total of 124 patients were included, with 62 in each group. The groups were well balanced regarding histology, PFI and number of previous treatment lines. Median PFS (mPFS) was 19.5 months for the Bev group versus 16.0 months for CT group (p = 0.150). By multivariate analysis, the HR for PFS was 2.25 (95% CI: 1.10-4.60) for CCNE1 overexpression. The benefit of bevacizumab was larger in the subgroups of patients with PFI 6-12 months (mPFS 18.6 versus 10.4 months, p = 0.002) and CCNE1 overexpression (mPFS 16.3 versus 7.0 months, p = 0.010). In conclusion, CCNE1 overexpression and PFI may suggest which patients will receive the greatest benefit from bevacizumab. These data, if confirmed by other studies, could help better select patients for antiangiogenic therapy.

TOP2A/MCM2, p16INK4a, and cyclin E1 expression in liquid-based cytology: a biomarkers panel for progression risk of cervical premalignant lesions.

BACKGROUND: To improve the efficiency of early diagnosis systems for cervical cancer, the use of cellular and viral markers for identifying precancerous lesions with a greater probability to progress to cancer has been proposed. Several cellular proteins and markers of oxidative DNA damage have been suggested as possible biomarkers of cervical carcinogenesis; however, they have not been evaluated together. In this study, we analyzed the expression of the cellular markers p16INK4a, Ki-67, CyclinE1, TOP2A/MCM2, and telomerase, as well as the DNA oxidative damage markers ROS and 8-OHdG. The analyses were performed in liquid-based cervical cytology samples or biopsies with premalignant lesions or cervical cancer diagnosis, with the purpose of selecting a panel of biomarkers that allow the identification of precursor lesions with greater risk of progression to cervical cancer. METHODS: We analyzed 1485 liquid-based cytology samples, including 239 non-squamous intraepithelial lesions (NSIL), 901 low-grade squamous intraepithelial lesions (LSIL), 54 high-grade squamous intraepithelial lesions (HSIL), and 291 cervical cancers (CC). The biomarkers were analyzed by immunocytochemistry and Human Papilloma Virus (HPV) genotyping with the INNO-LiPA genotyping Extra kit. RESULTS: We found that all tested cellular biomarkers were overexpressed in samples with high risk-HPV infection, and the expression levels increased with the severity of the lesion. TOP2A/MCM2 was the best biomarker for discriminating between LSIL and HSIL, followed by p16INK4a and cyclinE1. Statistical analysis showed that TOP2A/MCM2 provided the largest explanation of HSIL and CC cases (93.8%), followed by p16INK4a (91%), cyclin E1 (91%), Ki-67 (89.3%), and telomerase (88.9%). CONCLUSIONS: We propose that the detection of TOP2A/MCM2, p16INK4a and cyclin E1 expression levels is useful as a panel of biomarkers that allow identification of cervical lesions with a higher risk for progression to CC with high sensitivity and precision; this can be done inexpensively, in a single and non-invasive liquid-based cytology sample.

Regulation of cyclin E1 expression in human pluripotent stem cells and derived neural progeny.

Human pluripotent stem cells (hPSCs), including embryonic and induced pluripotent stem cells (hESCs and hiPSCs) show unique cell cycle characteristics, such as a short doubling time due to an abbreviated G1 phase. Whether or not the core cell cycle machinery directly regulates the stemness and/or the differentiation potential of hPSCs remains to be determined. To date, several scenarios describing the atypical cell cycle of hPSCs have been suggested, and therefore there is still controversy over how cyclins, master regulators of the cell cycle, are expressed and regulated. Furthermore, the cell cycle profile and the expression pattern of major cyclins in hESCs-derived neuroprogenitors (NP) have not been studied yet. Therefore, herein we characterized the expression pattern of major cyclins in hPSCs and NP. We determined that all studied cyclins mRNA expression levels fluctuate along cell cycle. Particularly, after a thorough analysis of synchronized cell populations, we observed that cyclin E1 mRNA levels increased sharply in G1/S concomitantly with cyclin E1 protein accumulation in hPSCs and NP. Additionally, we demonstrated that cyclin E1 mRNA expression levels involves the activation of MEK/ERK pathway and the transcription factors c-Myc and E2Fs in hPSCs. Lastly, our results reveal that proteasome mediates the marked down-regulation (degradation) of cyclin E1 protein observed in G2/M by a mechanism that requires a functional CDK2 but not GSK3ß activity. ABBREVIATIONS: hPSCs: human pluripotent stem cells; hESCs: human embryonic stem cells; hiPSCs: human induced pluripotent stem cells; NP: neuroprogenitors; HF: human foreskin fibroblasts; MEFs: mouse embryonic fibroblasts; iMEFs: irradiated mouse embryonic fibroblasts; CDKs: cyclindependent kinases; CKIs: CDK inhibitors; CNS: central nervous system; Oct-4: Octamer-4; EB: embryoid body; AFP: Alpha-fetoprotein; cTnT: Cardiac Troponin T; MAP-2: microtubule-associated protein; TUJ-1: neuron-specific class III ß-tubulin; bFGF: basic fibroblastic growth factor; PI3K: Phosphoinositide 3-kinase; KSR: knock out serum replacement; CM: iMEF conditioned medium; E8: Essential E8 medium.

SALL2 represses cyclins D1 and E1 expression and restrains G1/S cell cycle transition and cancer-related phenotypes.

SALL2 is a poorly characterized transcription factor that belongs to the Spalt-like family involved in development. Mutations on SALL2 have been associated with ocular coloboma and cancer. In cancers, SALL2 is deregulated and is proposed as a tumor suppressor in ovarian cancer. SALL2 has been implicated in stemness, cell death, proliferation, and quiescence. However, mechanisms underlying roles of SALL2 related to cancer remain largely unknown. Here, we investigated the role of SALL2 in cell proliferation using mouse embryo fibroblasts (MEFs) derived from Sall2-/- mice. Compared to Sall2+/+ MEFs, Sall2-/- MEFs exhibit enhanced cell proliferation and faster postmitotic progression through G1 and S phases. Accordingly, Sall2-/- MEFs exhibit higher mRNA and protein levels of cyclins D1 and E1. Chromatin immunoprecipitation and promoter reporter assays showed that SALL2 binds and represses CCND1 and CCNE1 promoters, identifying a novel mechanism by which SALL2 may control cell cycle. In addition, the analysis of tissues from Sall2+/+ and Sall2-/- mice confirmed the inverse correlation between expression of SALL2 and G1-S cyclins. Consistent with an antiproliferative function of SALL2, immortalized Sall2-/- MEFs showed enhanced growth rate, foci formation, and anchorage-independent growth, confirming tumor suppressor properties for SALL2. Finally, cancer data analyses show negative correlations between SALL2 and G1-S cyclins' mRNA levels in several cancers. Altogether, our results demonstrated that SALL2 is a negative regulator of cell proliferation, an effect mediated in part by repression of G1-S cyclins' expression. Our results have implications for the understanding and significance of SALL2 role under physiological and pathological conditions.

Synthesis and biological activity of two pregnane derivatives with a triazole or imidazole ring at C-21.

Pregnane derivatives are studied as agents for the treatment of different hormone-dependent diseases. The biological importance of these steroids is based on their potential use against cancer. In this study, we report the synthesis, characterization and biological activity of two pregnane derivatives with a triazole (3ß-hydroxy-21-(1H-1,2,4-triazol-1-yl)pregna-5,16-dien-20-one; T-OH) or imidazole (3ß-hydroxy-21-(1H-imidazol-1-yl)pregna-5,16-dien-20-one; I-OH) moieties at C-21. These derivatives were synthesized from 16-dehydropregnenolone acetate. The activity on cell proliferation of the compounds was measured on three human cancer cells lines: prostate cancer (PC-3), breast cancer (MCF7) and lung cancer (SK-LU-1). The cytotoxic and antiproliferative effects of T-OH and I-OH were assessed by using SBR and XTT methods, respectively. The gene expressions were evaluated by real time PCR. In addition, results were complemented by docking studies and transactivation assays using an expression vector to progesterone and androgen receptor. Results show that the two compounds inhibited the three cell lines proliferation in a dose-dependent manner. Compound I-OH downregulated the gene expression of the cyclins D1 and E1 in PC-3 and MFC7 cells; however, effect upon Ki-67, EAG1, BIM or survivin genes was not observed. Docking studies show poor interaction with the steroid receptors. Nevertheless, the transactivation assays show a weak antagonist effect of I-OH on progesterone receptor but not androgenic or antiandrogenic actions. In conclusion, the synthesized compounds inhibited cell proliferation as well as genes key to cell cycle of PC-3 and MCF7 cell lines. Therefore, these compounds could be considered a good starting point for the development of novel therapeutic alternatives to treat cancer.