High neutrophil-to-lymphocyte ratio is a predictor of short-term survival for patients with recurrent cervical cancer after radiation-based therapy.

AIM: Patients with recurrent cervical cancer after radiotherapy have poor prognoses because of the lack of effective treatment options. Biomarkers to predict survival outcomes for recurrent cervical cancer are warranted because patients with limited life expectancy sometimes benefit from less aggressive treatment in combination with early palliative care. Therefore, we aimed to explore a predictive biomarker for the outcomes of patients with recurrent cervical cancer. METHODS: We retrospectively investigated 231 patients initially treated with radiation-based therapy between January 2004 and December 2015. The associations between clinicopathological features at the time of relapse and overall survival after relapse were assessed. As factors which reflect patients' conditions, we particularly focused on C-reactive protein-to-albumin ratio (CAR) and neutrophil-to-lymphocyte ratio (NLR) at the time of relapse. Additionally, we investigated biomarkers predictive of short-term survival. RESULTS: Among 231 patients, 91 patients experienced relapse and 74 patients died during the follow-up period. Multivariate analysis revealed that treatment after relapse, CAR, and NLR was significantly associated with overall survival. Among them, treatment after relapse significantly affected survival outcomes, and patients who received definitive local treatment had a better 3-year survival rate than those who received other treatments. Conversely, NLR was the most influential biomarker for short-term survival, and the prognosis of patients with high NLRs was much worse than those with low NLRs. CONCLUSIONS: This study thus demonstrated that, for the patients with recurrent cervical cancer who received radiation-based therapy, definitive local treatment can provide long-term survival and extremely high NLRs are predictive of short-term survival.

Epigenetic Modifier SETD8 as a Therapeutic Target for High-Grade Serous Ovarian Cancer.

The histone methyltransferase SETD8, which methylates the lysine 20 of histone H4 (H4K20), is reportedly involved in human carcinogenesis along with nonhistone proteins such as p53. However, its expression profiles and functions in the context of high-grade serous ovarian carcinoma (HGSOC) are still unknown. The purpose of this study was to investigate the role of SETD8 in HGSOC. We performed quantitative real-time PCR and immunohistochemistry to detect the expression of SETD8 in HGSOC samples and normal ovarian specimens. Then, we assessed the effect of the inhibition of SETD8 expression using small interfering RNA (siRNA) and a selective inhibitor (UNC0379) on cell proliferation and apoptosis in HGSOC cells. The expression of SETD8 was significantly upregulated in clinical ovarian cancer specimens compared to that in the corresponding normal ovary. In addition, suppression of SETD8 expression in HGSOC cells with either siRNA or UNC0379 resulted in reduced levels of H4K20 monomethylation, inhibition of cell proliferation, and induction of apoptosis. Furthermore, UNC0379 showed a long-term antitumor effect against HGSOC cells, as demonstrated by colony-formation assays. SETD8 thus constitutes a promising therapeutic target for HGSOC, warranting further functional studies.

Extreme skeletal muscle loss during induction chemotherapy is an independent predictor of poor survival in advanced epithelial ovarian cancer patients.

AIM: Skeletal muscle loss is often observed in advanced cancer patients. This study investigates whether skeletal muscle loss is associated with survival outcomes of advanced epithelial ovarian cancer (EOC) patients after induction chemotherapy (IC) in a Japanese cohort. Whether serum inflammatory markers are associated with skeletal muscle changes is also addressed. METHODS: We retrospectively reviewed 60 patients with stage III/IV EOC who underwent IC between 2010 and 2017. Skeletal muscle area (SMA) was measured at the third lumbar vertebrae level on a single axial computed tomography-scan image. Receiver operating curve analysis was used to determine cut-off values of pre- and post-IC SMA and SMA ratio (SMAR). Univariate and multivariate analyses of overall survival (OS) were conducted using the log-rank test and Cox proportional hazards regression model, respectively. RESULTS: The SMA decreased significantly after IC (P = 0.019). The cut-off value between low and high SMAR was 0.96. High or low SMAR was observed in 34 (57%) and 26 (43%) patients, respectively. Univariate analysis revealed that low SMAR was associated with poor OS (P = 0.025). Multivariate analysis showed that incomplete resection during interval debulking surgery (hazard ratio, 0.30; 95% CI, 0.11-0.80; P = 0.016) and a low SMAR (hazard ratio, 3.17; 95% CI, 1.18-9.06; P = 0.022) were independent predictors of poor OS. Of the serum inflammatory markers investigated, only post-IC absolute neutrophil count correlated significantly with SMAR (P = 0.012). CONCLUSION: Low SMAR can be used to predict poor prognosis in advanced EOC patients who have undergone IC.

The histone methyltransferase SMYD2 is a novel therapeutic target for the induction of apoptosis in ovarian clear cell carcinoma cells.

Previous studies have suggested that histone methylation can modulate carcinogenesis and cancer progression. For instance, the histone methyltransferase SET and MYND domain containing 2 (SMYD2) is overexpressed in several types of cancer tissue. The aim of the present study was to determine whether SMYD2 could serve a therapeutic role in ovarian clear cell carcinoma (OCCC). Reverse transcription-quantitative PCR was used to examine SMYD2 expression in 23 clinical OCCC specimens. Moreover, OCCC cell proliferation and cell cycle progression were also examined following small interfering RNA-mediated SMYD2 silencing or treatment with a selective SMYD2 inhibitor. SMYD2 was significantly upregulated in clinical OCCC specimens, compared with normal ovarian tissue. In addition, SMYD2 knockdown decreased cell viability as determined via a Cell Counting Kit-8 assay. Moreover, the proportion of cells in the sub-G1 phase increased following SMYD2 knockdown, suggesting increased apoptosis. Treatment with the SMYD2 inhibitor LLY-507 suppressed OCCC cell viability. These results suggested that SMYD2 could promote OCCC viability, and that SMYD2 inhibition induced apoptosis in these cells. Thus, SMYD2 inhibitors may represent a promising molecular targeted approach for OCCC treatment.

Postradiotherapy persistent lymphopenia as a poor prognostic factor in patients with cervical cancer receiving radiotherapy: a single-center, retrospective study.

BACKGROUND: Radiotherapy (RT) is effective in cervical cancer; radiation-induced lymphopenia correlates with poor survival outcome in several cancer types. We investigated the association of total lymphocyte count (TLC) with survival outcomes in patients with cervical cancer. METHODS: We retrospectively reviewed 168 patients with cervical cancer initially treated with definitive RT. We obtained clinicopathological data and TLCs before RT and at the end and at 6 months after RT. Patient-, treatment-, and tumor-specific factors were evaluated to determine their predictive values for overall survival. The association of overall and progression-free survivals with lymphopenia at each point was evaluated. RESULTS: Median follow-up duration was 44 (interquartile range: 25-67) months. Median TLCs before RT and at the end and at 6 months after RT were 1625/mm3, 400/mm3, and 800/mm3 (interquartile range: 1270-1930/mm3, 290-550/mm3, and 600-1067/mm3), respectively. For overall survival, in addition to FIGO stage, body mass index, histology, treatment, and presence of para-aortic lymph node metastasis, lymphopenia at 6 months after RT was a poor prognostic factor in multivariate analysis (P = 0.0026; hazard ratio [HR], 3.06; 95% confidence interval [CI]: 1.48-6.33). For progression-free survival, TLCs before and at 6 months after RT were poor prognostic factors in univariate analysis (P = 0.0318 and 0.0081, respectively); however, the latter was the only independent prognostic factor in multivariate analysis (P = 0.0021; HR, 2.67; 95% CI: 1.43-4.99). CONCLUSION: Post-RT persistent lymphopenia could be a poor prognostic factor for patients with cervical cancer who receive RT.

Anti-tumor activity of dual inhibition of phosphatidylinositol 3-kinase and MDM2 against clear cell ovarian carcinoma.

INTRODUCTION: PI3K pathway signaling has received attention as a molecular target in clear cell ovarian carcinoma (CCOC). MDM2 is one of the AKT effectors in the PI3K pathway, which binds to and degrades p53. In this study, we aimed to clarify the prognostic significance of PIK3CA and MDM2 expression, and potential therapeutic effect of a dual inhibition of the PI3K pathway and MDM2. MATERIALS AND METHODS: cDNA expression was evaluated by using microarray data using 75 samples of CCOC. DS-7423 (dual inhibitor of pan-PI3K and mTOR) and RG7112 (MDM2 inhibitor) were used on CCOC cell lines to evaluate cell proliferation, expression level of MDM2 related proteins, and apoptosis by MTT assay, western blotting, and flow cytometry. DS-7423 (3 mg/kg) and/or RG7112 (50 mg/kg) were orally administrated every day for three weeks, and the anti-tumor effect was evaluated using tumor xenografts, along with immunohistochemistry. RESULTS: Tumors with high expression of both PIK3CA and MDM2 showed significantly worse prognosis in expression array of 71 CCOCs (P = 0.013). Dual inhibition of the PI3K pathway by DS-7423 and MDM2 by RG7112 showed synergistic anti-proliferative effect in 4 CCOC cell lines without TP53 mutations. The combination therapy more robustly induced pro-apoptotic proteins (PUMA and cleaved PARP) with increase of sub G1 population and apoptotic cells, compared with either single agent alone. The combination therapy significantly reduced tumor volume in mice (P < 0.001 in OVISE, and P = 0.038 in RMG-I) without severe body weight loss. Immunohistochemistry from the xenograft tumors showed that the combination treatment significantly reduced vascularity and cell proliferation, with an increase of apoptotic cell death. CONCLUSION: A combination therapy targeting the PI3K pathway and MDM2 might be a promising therapeutic strategy in CCOC.

The histone methyltransferase WHSC1 is regulated by EZH2 and is important for ovarian clear cell carcinoma cell proliferation.

BACKGROUND: Wolf-Hirschhorn syndrome candidate gene-1 (WHSC1), a histone methyltransferase, has been found to be upregulated and its expression to be correlated with expression of enhancer of zeste homolog 2 (EZH2) in several cancers. In this study, we evaluated the role of WHSC1 and its therapeutic significance in ovarian clear cell carcinoma (OCCC). METHODS: First, we analyzed WHSC1 expression by quantitative PCR and immunohistochemistry using 23 clinical OCCC specimens. Second, the involvement of WHSC1 in OCCC cell proliferation was evaluated by MTT assays after siRNA-mediated WHSC1 knockdown. We also performed flow cytometry (FACS) to address the effect of WHSC1 on cell cycle. To examine the functional relationship between EZH2 and WHSC1, we knocked down EZH2 using siRNAs and checked the expression levels of WHSC1 and its histone mark H3K36m2 in OCCC cell lines. Finally, we checked WHSC1 expression after treatment with the selective inhibitor, GSK126. RESULTS: Both quantitative PCR and immunohistochemical analysis revealed that WHSC1 was significantly overexpressed in OCCC tissues compared with that in normal ovarian tissues. MTT assay revealed that knockdown of WHSC1 suppressed cell proliferation, and H3K36me2 levels were found to be decreased in immunoblotting. FACS revealed that WHSC1 knockdown affected the cell cycle. We also confirmed that WHSC1 expression was suppressed by EZH2 knockdown or inhibition, indicating that EZH2 is upstream of WHSC1 in OCCC cells. CONCLUSIONS: WHSC1 overexpression induced cell growth and its expression is, at least in part, regulated by EZH2. Further functional analysis will reveal whether WHSC1 is a promising therapeutic target for OCCC.

A low albumin to globulin ratio with a high serum globulin level is a prognostic marker for poor survival in cervical cancer patients treated with radiation based therapy.

OBJECTIVE: We investigated whether the pretreatment albumin to globulin ratio, serum albumin level, and serum globulin level can be used to predict survival among cervical cancer patients treated with radiation based therapy and assessed globulin fractions. METHODS: We retrospectively enrolled 128 patients with cervical cancer treated with radiation based therapy at our institution between 2010 and 2015. The associations of the pretreatment albumin to globulin ratio, and serum albumin and globulin levels with overall survival were assessed. Additionally, the associations of the globulin fractions with the serum globulin levels and overall survival were evaluated. RESULTS: Median follow-up duration was 30 months (IQR 16-44 months). A low albumin to globulin ratio (< 1.53) was found to be an independent prognostic factor for overall survival (HR= 3.07; 95% CI, 1.03 to 13.3; P=0.044). On evaluating serum globulin and albumin separately, a high serum globulin level was significantly associated with overall survival (cut-off value 2.9 g/dL; HR=3.74; 95% CI 1.08 to 23.6; P=0.036) whereas a low serum albumin level was not associated with overall survival (cut-off value 3.6 g/dL; HR=1.77; 95% CI 0.57 to 4.54; P=0.29). Electrophoresis data of the serum proteins revealed that the γ-globulin fraction was most strongly correlated with the globulin levels (P<0.001). Furthermore, a high γ-globulin level (≥1.28 g/dL) was significantly associated with poor overall survival (log rank test, P=0.034). CONCLUSIONS: A pretreatment low albumin to globulin ratio, which might be attributable to a high serum globulin level, can be used to predict poor prognosis in cervical cancer patients treated with radiation based therapy.

Lymphopenia after induction chemotherapy correlates with incomplete surgical resection in patients with advanced ovarian cancer.

BACKGROUND: Lymphopenia is associated with poor outcomes in patients with various cancers, but little is known about the prognostic impact of lymphopenia in patients with epithelial ovarian cancer (EOC) after induction chemotherapy (IC). This study investigated the prognostic significance of pre- and post-IC lymphopenia in patients with advanced EOC. METHODS: We reviewed medical records of 68 patients with stage III/IV ovarian, fallopian tube, or peritoneal cancer treated with IC at our institution between 2009 and 2017. We assessed the associations of pre- and post-IC inflammatory markers, including lymphocyte counts, with several oncological outcomes, such as the implementation of interval debulking surgery (IDS), complete resection, progression-free survival (PFS), and overall survival (OS). RESULTS: Lymphocyte counts increased significantly post-IC compared with the pre-IC values (P = 0.009). Pre-IC lymphopenia was observed in 27 patients (40%), whereas only 16 patients (24%) displayed lymphopenia post-IC (P = 0.020). Among several inflammatory markers, only post-IC lymphopenia was significantly associated with incomplete resection outcome during IDS (P = 0.012). Moreover, post-IC lymphopenia was significantly associated with poor PFS (log-rank test, P = 0.009), whereas pre-IC lymphopenia was associated with neither PFS nor OS. CONCLUSIONS: Post-IC lymphopenia may predict incomplete resection during IDS and poor prognosis in patients with advanced EOC.

Kaempferol, a natural dietary flavonoid, suppresses 17ß-estradiol-induced survivin expression and causes apoptotic cell death in endometrial cancer.

Endometrioid endometrial carcinoma, commonly known as type 1 endometrial cancer, accounts for >80% of endometrial carcinomas and is dependent on estrogen. We recently reported on the prognostic significance of the BIRC5 survivin gene in endometrial cancer. Estradiol induces survivin expression in estrogen receptor-positive, but not in estrogen receptor-negative, cancer cells. Kaempferol, a bioflavonoid, reportedly inhibits estrogen receptor-α (ERα) in hormone receptor-positive breast cancer cells. However, whether kaempferol-mediated inhibition of ERα suppresses survivin and induces cell death in endometrial cancer remains unclarified. The present study evaluated the antitumor effects of kaempferol on endometrial cancer cells. Cell viability assays, flow cytometry analysis, western blotting and annexin V analyses were used to analyze the antitumor effects of kaempferol. The results demonstrated that kaempferol successfully suppressed the viability of two ER-positive endometrial cancer cell lines, with IC50 values of 83 and 65 µM. In addition, kaempferol induced sub-G1 cell accumulation and apoptotic cell death (P<0.01) in a dose-dependent manner. Treatment of cells with estradiol significantly induced co-expression of nuclear ERα and survivin proteins (P<0.001). Further evaluation revealed that kaempferol causes apoptotic cell death largely by suppressing ERα, survivin and Bcl-2 protein. Therefore, the results of the present study suggested that targeting ERα and survivin with kaempferol may be a novel therapeutic option against endometrial carcinoma.

Blood Vessel Invasion Is a Strong Predictor of Postoperative Recurrence in Endometrial Cancer.

OBJECTIVES: Although lymphovascular space invasion is a prognostic factor for the recurrence of resectable endometrial cancer, the differential impacts of lymphatic vessel invasion (LVI) and blood vessel invasion (BVI) on the recurrence of endometrial cancer are poorly described. We investigated the prognostic significance of LVI and BVI on the recurrence of endometrial cancer and their association with patterns of recurrence. METHODS: We retrospectively reviewed 376 patients with stage I to III endometrial cancer who underwent surgery with curative intent at our institution between 2007 and 2015. The associations of the presence of lymphovascular space invasion or LVI and BVI with recurrence-free survival and patterns of recurrence were evaluated. RESULTS: Lymphovascular space invasion positivity was an independent prognostic factor for recurrence-free survival (hazards ratio [HR], 3.070; 95% confidence interval [CI], 1.404-6.824; P = 0.0048). However, when categorized by LVI versus BVI, the latter was a strong independent prognostic factor (HR, 2.697; CI, 1.288-5.798; P = 0.0081), whereas the former was not (HR, 1.740; CI, 0.795-3.721; P = 0.1637). Hematogenous metastasis was the most prevalent form of recurrence in endometrial cancer (24 [50%] of all 48 recurrent cases). Notably, 17 (19.5%) of 87 patients with BVI developed hematogenous metastases, compared with 7 (2.4%) of 289 without BVI (χ test, P < 0.0001). CONCLUSIONS: Blood vessel invasion rather than LVI was a strong predictor of postoperative recurrence in stage I to III endometrial cancer, probably due to its predisposition to hematogenous metastases.

Oncogenic histone methyltransferase EZH2: A novel prognostic marker with therapeutic potential in endometrial cancer.

The histone methyltransferase EZH2, a key epigenetic modifier, is known to be associated with human tumorigenesis. However, the physiological importance of EZH2 and its clinical relevance in endometrial cancer remain unclear. Hence, in the present study, we investigated the expression and function of EZH2 in endometrial cancer. In a quantitative real-time PCR analysis of 11 endometrial cancer cell lines and 52 clinical endometrial cancer specimens, EZH2 was significantly overexpressed in cancer cells and tissues compared to that in corresponding normal control cells and tissues. Kaplan-Meier survival analysis using data of the TCGA RNA-seq database and tissue microarrays (TMAs) indicated that EZH2 overexpression is associated with endometrial cancer prognosis. In addition, knockdown of EZH2 using specific siRNAs resulted in growth suppression and apoptosis induction of endometrial cancer cells, accompanied by attenuation of H3K27 trimethylation. Consistent with these results, treatment with GSK126, a specific EZH2 inhibitor, suppressed endometrial cancer cell growth and decreased the number of cancer cell colonies. Furthermore, GSK126 showed additive effects with doxorubicin or cisplatin, which are conventional drugs for treatment of endometrial cancer. Further studies should explore the therapeutic potential of inhibiting EZH2 in patients with endometrial cancer.

Autophagy inhibition augments resveratrol-induced apoptosis in Ishikawa endometrial cancer cells.

Resveratrol (RSV), a polyphenolic compound derived from red wine, inhibits the proliferation of various types of cancer. RSV induces apoptosis in cancer cells, while enhancing autophagy. Autophagy promotes cancer cell growth by driving cellular metabolism, which may counteract the effect of RSV. The present study aimed to elucidate the correlation between RSV and autophagy and to examine whether autophagy inhibition may enhance the antitumor effect of RSV in endometrial cancer cells. Cell proliferation, cell cycle progression and apoptosis were examined, following RSV exposure, by performing MTT assays, flow cytometry and annexin V staining, respectively, in an Ishikawa endometrial cancer cell line. Autophagy was evaluated by measuring the expression levels of light chain 3, II (LC3-II; an autophagy marker) by western blotting and immunofluorescence. Chloroquine (CQ) and small interfering RNAs targeting autophagy related (ATG) gene 5 (ATG5) or 7 (ATG7) were used to inhibit autophagy, and the effects in combination with RSV were assessed using MTT assays. RSV treatment suppressed cell proliferation in a dose-dependent manner in Ishikawa cells. In addition, RSV exposure increased the abundance of the sub-G1 population and induced apoptosis. LC3-II accumulation was observed following RSV treatment, indicating that RSV induced autophagy. Combination treatment with CQ and RSV more robustly suppressed growth inhibition and apoptosis, compared with RSV treatment alone. Knocking down ATG5 or ATG7 expression significantly augmented RSV-induced apoptosis. The results of the present study indicated that RSV-induced autophagy may counteract the antitumor effect of RSV in Ishikawa cells. Combination treatment with RSV and an autophagy inhibitor, such as CQ, may be an attractive therapeutic option for treating certain endometrial cancer cells.

MDM2 is a potential therapeutic target and prognostic factor for ovarian clear cell carcinomas with wild type TP53.

MDM2, a ubiquitin ligase, suppresses wild type TP53 via proteasome-mediated degradation. We evaluated the prognostic and therapeutic value of MDM2 in ovarian clear cell carcinoma. MDM2 expression in ovarian cancer tissues was analyzed by microarray and real-time PCR, and its relationship with prognosis was evaluated by Kaplan-Meier method and log-rank test. The anti-tumor activities of MDM2 siRNA and the MDM2 inhibitor RG7112 were assessed by cell viability assay, western blotting, and flow cytometry. The anti-tumor effects of RG7112 in vivo were examined in a mouse xenograft model. MDM2 expression was significantly higher in clear cell carcinoma than in ovarian high-grade serous carcinoma (P = 0.0092) and normal tissues (P = 0.035). High MDM2 expression determined by microarray was significantly associated with poor progression-free survival and poor overall survival (P = 0.0002, and P = 0.0008, respectively). Notably, RG7112 significantly suppressed cell viability in clear cell carcinoma cell lines with wild type TP53. RG7112 also strongly induced apoptosis, increased TP53 phosphorylation, and stimulated expression of the proapoptotic protein PUMA. Similarly, siRNA knockdown of MDM2 induced apoptosis. Finally, RG7112 significantly reduced the tumor volume of xenografted RMG-I clear cell carcinoma cells (P = 0.033), and the density of microvessels (P = 0.011). Our results highlight the prognostic value of MDM2 expression in clear cell carcinoma. Thus, MDM2 inhibitors such as RG7112 may constitute a class of potential therapeutics.

Significance of survivin as a prognostic factor and a therapeutic target in endometrial cancer.

INTRODUCTION: Survivin is an anti-apoptotic protein encoded by the baculoviral inhibitor of apoptosis repeat-containing (BIRC5) gene and is upregulated in 83% of endometrial cancers. We aimed to elucidate the prognostic importance of BIRC5 expression, and evaluate survivin as a therapeutic target for endometrial cancer, by knock-down of BIRC5 and using the survivin inhibitor-YM155. METHODS: RNA sequencing data in 234 patients with endometrial carcinoma was obtained from The Cancer Genome Atlas database, and analyzed using Kaplan-Meier method, log-rank test and Cox proportional hazard model. Expressions of survivin in 16 endometrial cancer cell lines were analyzed by western blotting. Knocking down effect on survivin expression was evaluated using a small interfering RNA (siRNA). The anti-proliferative and pro-apoptotic effects of YM155 were assessed with cell viability, flow cytometry, and annexin V/propidium iodide assays. RESULTS: High expression of BIRC5 was associated with poor progression free survival (P=0.006), and shown to be an independent prognostic factor (HR=1.97, 95% CI=1.29-4.5, P=0.045). Survivin was upregulated in 14 of 16 (87.5%) endometrial cancer cell lines, compared with endometrial immortalized cells. Apoptosis was induced by knockdown of BIRC5 in all 3 cell lines examined. YM155 showed increased population of sub-G1 cells (P<0.001) in all 16 cell lines, and IC50 values to YM155 were <50nm in 15 cell lines. YM155 dose-dependently and significantly increased the apoptotic cell population in all 16 cell lines (P<0.001). CONCLUSIONS: Present study indicated that survivin expression is a significant prognostic factor and that survivin is a promising therapeutic target for endometrial cancer.

Characterization of TP53 and PI3K signaling pathways as molecular targets in gynecologic malignancies.

Recent developments in genomic analysis have unveiled the key signaling pathways in human cancer. However, only a limited number of molecular-targeted drugs are applicable for clinical use in gynecologic malignancies. TP53 signaling and phosphatidylinositol 3 kinase pathways are frequently mutated in cancer, and have received much attention as molecular targets in human cancers. In this review, we mainly focus on the functions of these pathways, and discuss the molecular-targeted drugs under clinical trials. The molecular-targeted drugs described in this review include dual phosphatidylinositol 3 kinase/mTOR inhibitors (NVP-BEZ235, DS-7423, SAR245409), an mTOR inhibitor (everolimus), an MEK inhibitor (pimasertib), an autophagy inhibitor (chloroquine), a cyclin-dependent kinases 4/6 inhibitor (PD0332991), and a poly (ADP-ribose) polymerase inhibitor (olaparib).

Synergistic antitumor effects of combination PI3K/mTOR and MEK inhibition (SAR245409 and pimasertib) in mucinous ovarian carcinoma cells by fluorescence resonance energy transfer imaging.

The aim of this study was to clarify the synergistic effects of dual inhibition of the PI3K/mTOR and MAPK pathways in ovarian mucinous carcinoma (OMC) cells, using fluorescence resonance energy transfer (FRET) imaging. We exposed 6 OMC cell lines to a PI3K/mTOR inhibitor (voxtalisib, SAR245409) and/or a MEK inhibitor (pimasertib), and evaluated synergistic effects using the Chou-Talalay method. Then, S6K (PI3K pathway) and ERK (MAPK pathway) kinase activities, and their individual proliferative or cytotoxic effects were calculated by time-lapse FRET imaging. In combination with SAR245409, pimasertib (30 nM) synergistically inhibited cell growth (combination indexes: 0.03-0.5) and induced apoptosis in all 6 OMC cell lines. FRET-imaging results demonstrated that ERK inhibition induced both anti-proliferation and apoptosis in a dose-dependent manner in both MCAS and OAW42 cells. However, S6K inhibition suppressed proliferation in a threshold manner in both cell lines, although apoptosis was only induced in OAW42 cells. These results demonstrated that combined PI3K/mTOR and MEK inhibition exhibited synergistic antitumor effects in OMC cells and that FRET imaging is useful for analyzing kinase activities in live cells and elucidating their cytostatic and cytotoxic effects.

Prognostic importance of CDK4/6-specific activity as a predictive marker for recurrence in patients with endometrial cancer, with or without adjuvant chemotherapy.

BACKGROUND: Pathologically low-risk endometrial cancer patients do not receive postoperative treatment; however, 10-15% of these patients show recurrence with poor prognosis. We evaluated the clinical importance of cyclin-dependent kinase 4/6 (CDK4/6) activity, and its significance as a novel biomarker for the prognosis and chemo-sensitivity of endometrioid endometrial carcinoma (EEC). METHODS: Cyclin-dependent kinase 4/6 expression and enzyme activity in 109 tumour samples from patients with EEC were examined with a cell-cycle profiling (C2P) assay. CDK4/6-specific activity (CDK4/6SA) was determined, and its relationship with clinicopathological factors and expression of Ki-67 was analysed. RESULTS: CDK4/6-specific activity was significantly correlated with Ki-67 (P=0.035), but not with any other clinicopathological characteristics. CDK4/6SA was significantly higher (P=0.002) in pathologically low-risk patients (not receiving adjuvant chemotherapy, n=74) than in intermediate- or high-risk patients (receiving adjuvant chemotherapy, n=35). In addition, patients with high CDK4/6SA (>3.0) showed significantly (P=0.024) shorter progression-free survival (PFS) than those with low CDK4/6SA (<3.0). Although Ki-67 expression itself was not a marker for prognosis, the combination of high CDK4/6SA and high Ki-67 expression (>15%) was robustly associated with shorter PFS (P=0.015), and this combination was an independent poor prognostic factor in the low-risk group. Inversely, in the intermediate-/high-risk group, patients with high CDK4/6SA had a tendency of a more favourable prognosis compared with patients with low CDK4/6SA (P=0.063). CONCLUSIONS: CDK4/6-specific activity can be used as a biomarker to predict prognosis and, possibly, chemo-sensitivity. The combination of Ki-67 expression might strengthen the clinical usefulness of CDK4/6SA as a biomarker.

Antitumor activity of a combination of dual PI3K/mTOR inhibitor SAR245409 and selective MEK1/2 inhibitor pimasertib in endometrial carcinomas.

OBJECTIVE: We aimed to clarify whether dual inhibition of PI3K/MAPK and MAPK pathways synergistically suppresses cell growth in endometrial cancer cells. METHODS: We exposed a panel of 12 endometrial cancer cell lines to a PI3K/mTOR inhibitor (voxtalisib, SAR245409) and/or a MEK inhibitor (pimasertib). The effect of each drug singly or in combination was evaluated by MTT assay, flow cytometry, and immunoblotting. Combination indexes (CIs) were calculated using the Chou-Talalay method to evaluate the synergy. RESULTS: The IC50 values for SAR245409 and pimasertib varied from 0.5 µM to 7 µM and from 0.1 µM to >20 µM, respectively. A combination of both compounds (1 µM SAR245409 and 30 nM pimasertib) caused a synergistic antitumor effect in 6 out of 12 endometrial cell lines (CI, 0.07-0.46). The synergistic effect was exclusively observed in 6 pimasertib-sensitive cell lines (IC50 of pimasertib, ≤5 µM). We found that 30 nM pimasertib, a concentration much lower than the IC50 for each cell line, was sufficient to cause a synergistic effect with SAR245409. Flow cytometric analysis showed that this combination significantly increased the population of G1 cells. However, a combination of rapamycin (an mTOR inhibitor) and pimasertib did not induce a synergistic effect in endometrial cancer cells, except for HEC-1B cells. CONCLUSIONS: The combination of a PI3K/mTOR inhibitor and a MEK inhibitor induced a synergistic antitumor effect in certain endometrial cancer cells. This study underscores the importance of using optimized doses of antitumor agents, singly or in combination, in treating endometrial cancer.

The anti-malarial chloroquine suppresses proliferation and overcomes cisplatin resistance of endometrial cancer cells via autophagy inhibition.

OBJECTIVE: The anti-malarial drug chloroquine (CQ) is also known as an autophagy inhibitor. Autophagy can promote tumor growth by fueling the necessary energy metabolism and inducing resistance to chemotherapy and/or irradiation in various human cancers. However, the role of autophagy in endometrial cancer has not yet been established. We investigated the anti-tumor effects and autophagy inhibition caused by CQ in endometrial cancer cells. METHODS: Cell proliferation and cell cycle were assessed in response to CQ in six endometrial cancer cell lines by using an MTT assay and/or flow cytometry. To assess the level of autophagy, western blotting and an immunofluorescence assay were used to measure LC3 expression. The effects of knockdown of either ATG5 or ATG7, both of which are indispensable for induction of autophagy, were assessed via an MTT assay. Sensitivity to CQ was compared between parental and cisplatin-resistant (CP-r) Ishikawa endometrial cancer cells. RESULTS: CQ suppressed proliferation in all six endometrial cancer cell lines in a dose-dependent manner, whereas it increased the population of apoptotic cells. Inhibition of autophagy via knockdown of either ATG5 or ATG7 decreased the sensitivity to CQ. Additionally, sensitivity to cisplatin was improved by knocking down ATG5 or ATG7. Finally, CP-r Ishikawa cells, with a high basal level of autophagy, were more sensitive to CQ than parental Ishikawa cells. CONCLUSIONS: Our data suggest that autophagy is involved in endometrial tumor growth and cisplatin resistance. Furthermore, our data support a therapeutic role for CQ in endometrial cancer cells with upregulation of autophagy.