Role of ADP receptors on platelets in the growth of ovarian cancer.

We investigated the effect of platelets on ovarian cancer and the role of adenosine diphosphate (ADP) receptors (P2Y12 and P2Y1) on platelets in the growth of primary ovarian cancer tumors. We showed that in murine models of ovarian cancer, a P2Y12 inhibitor (ticagrelor) reduced tumor growth by 60% compared with aspirin and by 75% compared with placebo. In P2Y12-/- mice, the growth of syngeneic ovarian cancer tumors was reduced by >85% compared with wild-type (WT) mice. In contrast, there was no difference in tumor growth between P2Y1-/- and WT mice. Reconstitution of hematopoiesis in irradiated P2Y12-/- mice by hematopoietic progenitor cells from WT mice (WT→P2Y12-/-) restored tumor growth in P2Y12-/- mice. Finally, knockdown of ecto-apyrase (CD39) on ovarian cancer cells increased tumor growth in tumor-bearing mice. Although in the absence of platelets, ADP, the P2Y12 inhibitor, recombinant apyrase, or knockdown of CD39 did not affect cancer cell proliferation, in the presence of platelets, the P2Y12 inhibitor and recombinant apyrase reduced and knockdown of CD39 increased platelet-enhanced cancer cell proliferation. These results suggest that P2Y12 on platelets and ADP concentration at the interface between cancer cells and platelets affect the growth of primary ovarian cancer tumors in mice. If additional studies in mice and in pilot human trials confirm our results, inhibition of P2Y12 might be a new therapeutic option that can be used in adjuvant to the traditional surgery and chemotherapy in patients with ovarian cancer.

Prognostic significance of systemic neutrophil and leukocyte alterations in surgically treated endometrial cancer patients: a monoinstitutional study.

OBJECTIVE: The aim of this study was to investigate the prognostic significance of an elevated neutrophil count at the time of the initial diagnosis in patients with surgically treated endometrial cancer. METHODS: The baseline characteristics and outcome data of patients who were diagnosed with endometrial cancer between January 2000 and December 2010 were collected and retrospectively reviewed. The patients were separated into two groups according to their neutrophil counts. The clinicopathological characteristics and overall survival rates of the two groups were compared. A Cox proportional hazard regression model was used to investigate the prognostic significance of an elevated neutrophil count among patients with surgically treated endometrial cancer. RESULTS: An elevated neutrophil count was found to be associated with an advanced clinical stage (P<0.0001), lymphovascular space involvement (P=0.0003), cervical involvement (P=0.0049), the proportion of patients that received adjuvant therapy (P=0.0020), elevated NLR (P<0.0001), and treatment failure (P<0.0001). Multivariate analyses demonstrated that age (hazard ratio (HR)=2.23, 95% confidence interval (95% CI)=1.30 to 3.91; P=0.0035), clinical stage (HR=4.72, 95% CI=2.61 to 8.90; P<0.0001), lymphovascular space involvement (HR=3.15, 95% CI=1.60 to 6.68; P=0.0007), an elevated neutrophil count (HR=2.76, 95% CI=1.43 to 5.03; P=0.0033), and an elevated white blood cell count (HR=2.79, 95% CI=1.50 to 4.96; P=0.0017) were significant predictors of survival. CONCLUSION: The elevated neutrophil or leukocyte counts at the time of the initial diagnosis are independent prognostic factors in patients with surgically treated endometrial cancer.

Efficacy of raloxifene hydrochloride for the prevention of health care problems in patients who undergo surgery for endometrial cancer: a multicenter randomized clinical trial.

OBJECTIVE: Removal of the ovaries is common during surgery for endometrial cancer. However, because loss of the ovaries can cause several health problems in patients, strategies for the prevention of such problems need to be established. Hence, we decided to conduct a multicenter randomized clinical trial to assess the effect of raloxifene on bone mineral density (BMD), bone metabolism, and the lipid profile of patients who had undergone surgery for patients with endometrial cancer. MATERIALS AND METHODS: Patients with endometrial cancer were enrolled after treatment. The participants were randomized into 2 groups: group 1 included 39 women who received alfacalcidol (1 µg/d) alone and group 2 included 37 women who received alfacalcidol and the test drug, raloxifene hydrochloride, at a dose of 60 mg/d. The BMD of lumbar spine and femoral neck, serum bone markers, as well as lipid profile parameters were evaluated at enrollment as well as 6, 12, and 24 months after the enrollment. The primary efficacy end point was the percentage change from baseline to 24 months in lumbar spine (L2-L4) and femoral neck BMD. RESULTS: Sixty-four women completed the 24-month study. At 24 months, the lumbar and femoral neck BMDs were significantly increased in group 2 compared with group 1 (3.5% vs -0.8% and 2.3% vs -2.8%, respectively). In group 2, low-density lipoprotein-cholesterol levels were significantly reduced by 13.6% and serum N-terminal telopeptide of type I collagen as well as bone-specific alkaline phosphatase values were significantly reduced by 16.7% and 25.7%, respectively. The patients who received adjuvant therapy for endometrial cancer showed a significantly higher response to raloxifene (5.8% vs 1.9%). Recurrence was detected in 2 (2.6%) patients in group 1. No severe adverse events were noted in any patient during the study period. CONCLUSIONS: Raloxifene exerts positive effects on BMD, bone metabolism, and lipid profile parameters and could provide an improved therapeutic option for patients with endometrial cancer.

miR-92a inhibits peritoneal dissemination of ovarian cancer cells by inhibiting integrin α5 expression.

Ovarian cancer is characterized by widespread peritoneal dissemination and ascites and has a cure rate of only 30%. As has been previously reported, integrin α5 plays a key role in the peritoneal dissemination of ovarian cancer. Our aim was to identify a new miRNA that regulates integrin α5 expression and analyze the therapeutic potential of targeting this miRNA. By using an IHC analysis, we proved that high integrin α5 expression correlates with a poor prognosis in Japanese patients with International Federation of Gynecology and Obstetrics stage III ovarian cancer. Based on an miRNA algorithm search, we identified hsa-mir-92a (miR-92a) as a candidate. The level of miR-92a expression was significantly inversely correlated with ITGA5 expression in various cancer cells. Transfection of precursor miR-92a reduced integrin α5 expression in ovarian cancer cells, which was accompanied by the inhibition of cancer cell adhesion, invasion, and proliferation. miR-92a overexpression reduced the luciferase activity of the ITGA5 3'-untranslated region, suggesting that ITGA5 mRNA is a direct target of miR-92a. In in vivo ovarian cancer xenografts, the enforced expression of miR-92a in HeyA-8 cells suppressed peritoneal dissemination. Although we still have a long way to go before an effective and nontoxic miRNA-based cancer therapy can be introduced into the clinic, the inhibition of integrin α5 expression by targeting miR-92a needs to be explored further for future applications in ovarian cancer treatment.

Combination treatment with trabectedin and irinotecan or topotecan has synergistic effects against ovarian clear cell carcinoma cells.

OBJECTIVES: The objective of this study was to investigate the chemotherapeutic agents that produce the strongest synergistic effects when combined with trabectedin against ovarian clear cell carcinoma (CCC), which is regarded as an aggressive chemoresistant histological subtype. METHODS: Using 4 human CCC cell lines (RMG1, RMG2, KOC7C, and HAC2), the cytotoxicities of trabectedin, SN-38, topotecan, doxorubicin, cisplatin, and paclitaxel as single agents were first assessed using the MTS assay. Then, the cytotoxicities of combination treatments involving trabectedin and 1 of the other 4 agents were evaluated by isobologram analysis to examine whether these combinations displayed synergistic, additive, or antagonistic effects. The antitumor activities of the combination treatments were also examined using cisplatin-resistant and paclitaxel-resistant CCC sublines, which were derived from the parental CCC cells by continuously exposing them to cisplatin or paclitaxel. Finally, we determined the effect of everolimus on the antitumor efficacy of trabectedin-based combination chemotherapy. RESULTS: Concurrent exposure to trabectedin and SN-38 or topotecan resulted in synergistic interactions in all 4 CCC cell lines. Among the tested combinations, trabectedin plus SN-38 was the most effective cytotoxic regimen. The combination of trabectedin plus SN-38 also had strong synergistic effects on both the cisplatin-resistant and paclitaxel-resistant CCC cell lines. Treatment with everolimus significantly enhanced the antitumor activity of trabectedin plus SN-38 or topotecan. CONCLUSIONS: Combination treatment with trabectedin and SN-38 displays the greatest cytotoxic effect against ovarian CCC. Our in vitro study provides the rationale for future clinical trials of trabectedin plus irinotecan with or without everolimus in patients with ovarian CCC in both the front-line chemotherapy setting and as a second-line treatment of recurrent CCC that had previously been treated with cisplatin or paclitaxel.

Elevated white blood cell count at the time of recurrence diagnosis is an indicator of short survival in patients with recurrent cervical cancer.

OBJECTIVES: The aim of this study was to investigate the prognostic significance of elevated white blood cell (WBC) count at the time of the diagnosis of cervical cancer recurrence. METHODS: The baseline characteristics and outcome data of 219 patients who had a diagnosis of recurrent cervical cancer between April 1996 and September 2010 were collected and reviewed. Survival after recurrence was compared between the leukocytosis group (WBC ≥9000/µL) and the nonleukocytosis group (WBC <9000/µL). A Cox proportional hazards regression model was used to investigate the prognostic significance of elevated WBC count in patients with recurrent cervical cancer. RESULTS: The patients in the leukocytosis group showed significantly shorter disease-free interval (P = 0.0005) and more frequently had multiple recurrences (P = 0.0101) than those in the nonleukocytosis group. The median survival after recurrence of the patients with elevated WBC count was 9 months, which was significantly shorter than the 21 months observed in the patients without normal WBC count (log rank; P < 0.0001). Multivariate analyses revealed that clinical stage, tumor diameter, histology, an elevated WBC count (≥9000/µL), and an elevated neutrophil count (≥6500/µL) were significant prognostic factors in survival after recurrence. CONCLUSION: The elevated WBC count at the time of the diagnosis of recurrence is an independent prognostic factor in patients with recurrent cervical cancer.

Prediction of progression-free survival and response to paclitaxel plus carboplatin in patients with recurrent or advanced cervical cancer.

OBJECTIVE: The aim of this study was to identify predictors of the response to paclitaxel-carboplatin chemotherapy (TC) in recurrent or patients with advanced cervical cancer. METHODS: The records of 61 consecutive women with recurrent or advanced cervical cancer who were treated with TC were retrospectively reviewed. Data regarding their primary disease, follow-up, recurrence, and the activity and toxicity of TC were collected. Multivariate analysis was performed using the Cox proportional hazards regression model to identify predictors of the response to TC. Survival was calculated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Overall, TC was well tolerated and displayed a response rate of 60.7% (19 complete response and 18 partial response). The median progression-free survival was 14 months for all patients and 20 months for the responders. Grade 3 to grade 4 toxicities were observed in 51 patients (83.6%). Multivariate analysis revealed that performance status, symptom status, and prior chemotherapy were independent prognostic predictors of a poor response. Patient survival was inversely correlated with the number of these prognostic factors. When the patients were divided into 2 prognostic groups (low risk: patients with no or one poor prognostic factor; and high-risk: patients with 2 or more poor prognostic factors), the patients in the high-risk group had a significantly shorter progression-free survival than those in the low-risk group (4 vs 16 months, log-rank; P < 0.0001). CONCLUSIONS: The combination of paclitaxel and carboplatin is effective in patients with recurrent or advanced cervical cancer. Our prognostic model composed of 3 clinical variables might enable physicians to identify patients who would not derive clinical benefit from TC and offer them the opportunity to receive other types of treatment.

Post-treatment follow-up procedures in cervical cancer patients previously treated with radiotherapy.

PURPOSE: We investigated the role of physical examination, CT scan, chest X-ray, and Pap smear in the routine follow-up program for cervical cancer patients previously treated with radiotherapy. METHODS: The records of women who had developed recurrent cervical cancer after radiotherapy were retrospectively reviewed. The optimal procedure for the detection of recurrence was evaluated according to the disease-free interval (DFI). Survival analysis was performed based on the Kaplan-Meier method and comparisons between groups were made using the log-rank test. RESULTS: A total of 146 recurrent cervical cancer patients were included in our database. The majority of recurrences were diagnosed either by symptoms, physical examination, or CT scan. The patients whose recurrent disease was detected by Pap smear, physical examination, or CT scan had a significantly longer survival than those detected by symptoms. When analyzed according to DFI, physical examination, and CT scan led to the detection of recurrence in patients with a DFI of 1-5 years. In contrast, chest X-ray and Pap smear only had a clinical impact on the diagnosis of recurrence in patients with a DFI of 1-2 years. CONCLUSIONS: Chest X-ray and Pap smear can be routinely performed for the first 2 years after radiotherapy, but can be omitted or used sparingly thereafter.

PRKRA/PACT Expression Promotes Chemoresistance of Mucinous Ovarian Cancer.

For mucinous ovarian cancer (MOC), standard platinum-based therapy is largely ineffective. We sought to identify possible mechanisms of oxaliplatin resistance of MOC and develop strategies to overcome this resistance. A kinome-based siRNA library screen was carried out using human MOC cells to identify novel targets to enhance the efficacy of chemotherapy. In vitro and in vivo validations of antitumor effects were performed using mouse MOC models. Specifically, the role of PRKRA/PACT in oxaliplatin resistance was interrogated. We focused on PRKRA, a known activator of PKR kinase, and its encoded protein PACT because it was one of the five most significantly downregulated genes in the siRNA screen. In orthotopic mouse models of MOC, we observed a significant antitumor effect of PRKRA siRNA plus oxaliplatin. In addition, expression of miR-515-3p was regulated by PACT-Dicer interaction, and miR-515-3p increased the sensitivity of MOC to oxaliplatin. Mechanistically, miR-515-3p regulated chemosensitivity, in part, by targeting AXL. The PRKRA/PACT axis represents an important therapeutic target in MOC to enhance sensitivity to oxaliplatin.

Role of Platelet-Derived Tgfß1 in the Progression of Ovarian Cancer.

Purpose: Transforming growth factor ß1 (Tgfß1) plays an important role in cancer. Most of Tgfß1 in plasma is from platelets; thus, we studied whether platelet Tgfß1 has any role in the progression of ovarian cancer, and whether this role is limited to metastasis or also involves the growth of primary tumors.Experimental Design: We compared the growth of murine ovarian cancer cell-induced tumors in platelet-specific Tgfß1-deficient mice and wild-type mice. Using resected tumor nodules, we studied the effect of platelet Tgfß1 on neoangiogenesis and on platelet extravasation into tumors. To investigate the effect of Tgfß1 at different stages of ovarian cancer, we reduced expression of Tgfß1 receptor (its TgfßR1 component) in tumors at different time points after injection of cancer cells, and compared the final tumor size.Results: Lack of platelet Tgfß1 in mice reduced tumor growth, neoangiogenesis, and platelet extravasation. Ovarian cancer tumors in platelet-specific Tgfß1-deficient mice reached less than half of their size in wild-type littermates. Knockdown of TgfßR1 on cancer cells in the first 2 weeks after their injection reduced tumor growth, but was less effective if initiated after 3 weeks.Conclusions: We showed that platelet Tgfß1 increased the growth of primary tumors in murine models of ovarian cancer. We also showed that inhibition of TgfßR1 is more effective in reducing the growth of ovarian cancer if initiated earlier. Our results supported a therapeutic benefit in preventing platelet activation, degranulation, and release of Tgfß1 in ovarian cancer. Clin Cancer Res; 23(18); 5611-21. ©2017 AACR.

Role of CTGF in Sensitivity to Hyperthermia in Ovarian and Uterine Cancers.

Even though hyperthermia is a promising treatment for cancer, the relationship between specific temperatures and clinical benefits and predictors of sensitivity of cancer to hyperthermia is poorly understood. Ovarian and uterine tumors have diverse hyperthermia sensitivities. Integrative analyses of the specific gene signatures and the differences in response to hyperthermia between hyperthermia-sensitive and -resistant cancer cells identified CTGF as a key regulator of sensitivity. CTGF silencing sensitized resistant cells to hyperthermia. CTGF small interfering RNA (siRNA) treatment also sensitized resistant cancers to localized hyperthermia induced by copper sulfide nanoparticles and near-infrared laser in orthotopic ovarian cancer models. CTGF silencing aggravated energy stress induced by hyperthermia and enhanced apoptosis of hyperthermia-resistant cancers.

Preclinical Efficacy for AKT Targeting in Clear Cell Carcinoma of the Ovary.

UNLABELLED: The aim of this study was to determine the role of AKT as a therapeutic target in ovarian clear cell carcinoma (CCC), an aggressive, chemoresistant histologic subtype of ovarian cancer. AKT activation was assessed by immunohistochemistry (IHC) using human tissue microarrays of primary ovarian cancers, composed of both CCC and serous adenocarcinoma (SAC). The growth-inhibitory effect of AKT-specific targeting by the small-molecule inhibitor, perifosine, was examined using ovarian CCC cell lines in vitro and in vivo. Finally, the activity of perifosine was examined using in CCC-derived tumors that had acquired resistance to anti-VEGF or chemotherapeutics such as bevacizumab or cisplatin, respectively. Interestingly, AKT was frequently activated both in early-stage and advanced-stage CCCs. Treatment of CCC cells with perifosine attenuated the activity of AKT-mTORC1 signaling, inhibited proliferation, and induced apoptosis. The effect of perifosine was more profound under conditions of high AKT activity compared with low AKT activity. Increased AKT activation and enhanced sensitivity to perifosine were observed in the context of cisplatin-resistant CCC. Treatment with perifosine concurrently with cisplatin significantly enhanced the antitumor effect of cisplatin. Moreover, perifosine showed significant antitumor activity in CCC-derived tumors that had acquired resistance to bevacizumab or cisplatin. Collectively, these data reveal that AKT is frequently activated in ovarian CCCs and is a promising therapeutic target in aggressive forms of ovarian cancer. IMPLICATIONS: AKT-targeted therapy has value in a first-line setting as well as a second-line treatment for recurrent disease developing after platinum-based chemotherapy or bevacizumab treatment.

The significance of lymphatic space invasion and its association with vascular endothelial growth factor-C expression in ovarian cancer.

The aim of this study is to investigate the significance of lymphatic space invasion (LSI) and tumor VEGF-C expression in the lymphatic spread of ovarian cancer. By performing immunostaining using human ovarian cancer specimens, we first investigated the association between the extent of LSI and tumor VEGF-C expression, tumor lymphangiogenesis, or the lymphatic metastasis. Moreover, by performing in vitro and in vivo experiments, we elucidated the role of VEGF-C in tumor lymphangiogenesis and lymph node metastasis as well as its role as a therapeutic target in ovarian cancer. The presence of LSI was associated with lymph node metastasis in patients with ovarian cancer. VEGF-C overexpression was significantly associated with the increased LSI and LVD in ovarian cancer. VEGF-C stimulated the lymphangiogenesis in vitro, induced the new lymph vessel formation, and increased the lymph node metastasis in mice models of ovarian cancer. The attenuation of VEGF-C expression by the treatment with mTORC1 inhibitor significantly inhibited lymphangiogenesis, and decreased lymph node metastasis in mice models of ovarian cancer. The presence of LSI is an indicator of nodal metastasis and is associated with higher tumor VEGF-C expression and worse clinical outcome of ovarian cancer patients. VEGF-C plays a crucial role in tumor lymphangiogenesis and lymph node metastasis of ovarian cancer.

Venous thromboembolism, interleukin-6 and survival outcomes in patients with advanced ovarian clear cell carcinoma.

BACKGROUND: We compared survival outcomes and risk of venous thromboembolism (VTE) among patients with advanced and early-stage ovarian clear cell carcinoma (OCCC) and serous ovarian carcinoma (SOC), as well as potential links with interleukin-6 (IL-6) levels. METHODS: A multicenter case-control study was conducted in 370 patients with OCCC and 938 with SOC. In a subset of 200 cases, pretreatment plasma IL-6 levels were examined. FINDINGS: Patients with advanced OCCC had the highest 2-year cumulative VTE rates (advanced OCCC 43.1%, advanced SOC 16.2%, early-stage OCCC 11.9% and early-stage SOC 6.4%, P<0.0001) and the highest median levels of IL-6 (advanced OCCC 17.8 pg/mL, advanced SOC 9.0 pg/mL, early-stage OCCC 4.2 pg/mL and early-stage SOC 5.0 pg/mL, P=0.006). Advanced OCCC (hazard ratio [HR] 3.38, P<0.0001), thrombocytosis (HR 1.42, P=0.032) and elevated IL-6 (HR 8.90, P=0.046) were independent predictors of VTE. In multivariate analysis, patients with advanced OCCC had significantly poorer 5-year progression-free and overall survival rates than those with advanced SOC (P<0.01), and thrombocytosis was an independent predictor of decreased survival outcomes (P<0.01). Elevated IL-6 levels led to poorer 2-year progression-free survival rates in patients with OCCC (50% versus 87.5%, HR 4.89, P=0.016) than in those with SOC (24.9% versus 40.8%, HR 1.40, P=0.07). INTERPRETATION: Advanced OCCC is associated with an increased incidence of VTE and decreased survival outcomes, which has major implications for clinical management of OCCC.

XPO1/CRM1 Inhibition Causes Antitumor Effects by Mitochondrial Accumulation of eIF5A.

PURPOSE: XPO1 inhibitors have shown promise for cancer treatment, and yet the underlying mechanisms for the antitumor effects are not well understood. In this study, we explored the usefulness of selective inhibitors of nuclear export (SINE) compounds that are specific inhibitors of XPO1. EXPERIMENTAL DESIGN: We used proteomic analysis in XPO1 inhibitor-treated ovarian cancer cell lines and examined antitumor effects in ovarian and breast cancer mouse models. We also studied the effects of XPO1 inhibitor in combination with chemotherapeutic agents. RESULTS: XPO1 inhibitor treatment substantially increased the percentage of apoptotic cells (60%) after 72 hours of incubation. XPO1 inhibitor promoted the accumulation of eIF5A in mitochondria, leading to cancer cell death. Topotecan showed the greatest synergistic effect with XPO1 inhibitor. XPO1 inhibitors prevented the translocation of IGF2BP1 from the nucleus to the cytoplasm, thereby permitting the localization of eIF5A in the mitochondria. This process was p53, RB, and FOXO independent. Significant antitumor effects were observed with XPO1 inhibitor monotherapy in orthotopic ovarian (P < 0.001) and breast (P < 0.001) cancer mouse models, with a further decrease in tumor burden observed in combination with topotecan or paclitaxel (P < 0.05). This mitochondrial accumulation of eIF5A was highly dependent on the cytoplasmic IGF2BP1 levels. CONCLUSIONS: We have unveiled a new understanding of the role of eIF5A and IGF2BP1 in XPO1 inhibitor-mediated cell death and support their clinical development for the treatment of ovarian and other cancers. Our data also ascertain the combinations of XPO1 inhibitors with specific chemotherapy drugs for therapeutic trials.

Uterine cervical cancer displaying tumor-related leukocytosis: a distinct clinical entity with radioresistant feature.

BACKGROUND: Tumor-related leukocytosis (TRL) is occasionally found in patients with nonhematopoietic malignancies. We investigated the clinical implication of TRL and individualized treatment for TRL-positive cervical cancer, as well as the underlying biological mechanism. METHODS: Clinical data from 258 cervical cancer patients treated with definitive radiotherapy were analyzed to investigate the association between TRL and treatment outcome. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were used to examine the mechanisms responsible for TRL in cervical cancer, focusing on the role of tumor-derived granulocyte colony-stimulating factor (G-CSF) and myeloid-derived suppressor cells (MDSCs). All statistical tests were two-sided. RESULTS: TRL was statistically significantly associated with younger age (Wilcoxon rank sum test, P = .03), larger tumor size (Wilcoxon rank sum test, P = .006), advanced clinical stage (χ(2) test, P = .01), and shorter overall survival (Cox proportional hazard modeling and Wald tests, P < .001). Among cervical cancer patients, TRL was associated with upregulated tumor G-CSF expression (χ(2) test, P < .001), elevated serum G-CSF levels (Student t test, P = .03), larger spleens (Student t test, P = .045), and increased MDSC frequencies in the blood (Student t test, P < .001) compared with the TRL-negative patients. In vitro and in vivo experiments revealed that tumor-derived G-CSF was involved in the underlying causative mechanism of TRL and MDSCs induced by tumor-derived G-CSF are responsible for the rapidly progressive and radioresistant nature of TRL-positive cervical cancer. The administration of anti-Gr-1 neutralizing antibody or the depletion of MDSCs by splenectomy (n = 6 per group) inhibited tumor growth and enhanced radiosensitivity in TRL-positive cervical cancer xenografts (Wilcoxon rank sum test, P = .008 and P = .02, respectively). CONCLUSIONS: TRL is associated with resistance to radiotherapy among cervical cancer patients, and MDSC-targeting treatments may have therapeutic potential in these patients.

Therapeutic silencing of KRAS using systemically delivered siRNAs.

Despite being among the most common oncogenes in human cancer, to date, there are no effective clinical options for inhibiting KRAS activity. We investigated whether systemically delivered KRAS siRNAs have therapeutic potential in KRAS-mutated cancer models. We identified KRAS siRNA sequences with notable potency in knocking down KRAS expression. Using lung and colon adenocarcinoma cell lines, we assessed antiproliferative effects of KRAS silencing in vitro. For in vivo experiments, we used a nanoliposomal delivery platform, DOPC, for systemic delivery of siRNAs. Various lung and colon cancer models were used to determine efficacy of systemic KRAS siRNA based on tumor growth, development of metastasis, and downstream signaling. KRAS siRNA sequences induced >90% knockdown of KRAS expression, significantly reducing viability in mutant cell lines. In the lung cancer model, KRAS siRNA treatment demonstrated significant reductions in primary tumor growth and distant metastatic disease, while the addition of CDDP was not additive. Significant reductions in Ki-67 indices were seen in all treatment groups, whereas significant increases in caspase-3 activity were only seen in the CDDP treatment groups. In the colon cancer model, KRAS siRNA reduced tumor KRAS and pERK expression. KRAS siRNAs significantly reduced HCP1 subcutaneous tumor growth, as well as outgrowth of liver metastases. Our studies demonstrate a proof-of-concept approach to therapeutic KRAS targeting using nanoparticle delivery of siRNA. This study highlights the potential translational impact of therapeutic RNA interference, which may have broad applications in oncology, especially for traditional "undruggable" targets.

Potential role of mTORC2 as a therapeutic target in clear cell carcinoma of the ovary.

The goal of this study was to examine the role of mTOR complex 2 (mTORC2) as a therapeutic target in ovarian clear cell carcinoma (CCC), which is regarded as an aggressive, chemoresistant histologic subtype. Using tissue microarrays of 98 primary ovarian cancers [52 CCCs and 46 serous adenocarcinomas (SAC)], activation of mTORC2 was assessed by immunohistochemistry. Then, the growth-inhibitory effect of mTORC2-targeting therapy, as well as the role of mTORC2 signaling as a mechanism for acquired resistance to the mTOR complex 1 (mTORC1) inhibitor RAD001 in ovarian CCC, were examined using two pairs of RAD001-sensitive parental (RMG2 and HAC2) and RAD001-resistant CCC cell lines (RMG2-RR and HAC2-RR). mTORC2 was more frequently activated in CCCs than in SACs (71.2% vs. 45.7%). Simultaneous inhibition of mTORC1 and mTORC2 by AZD8055 markedly inhibited the proliferation of both RAD001-sensitive and -resistant cells in vitro. Treatment with RAD001 induced mTORC2-mediated AKT activation in RAD001-sensitive CCC cells. Moreover, increased activation of mTORC2-AKT signaling was observed in RAD001-resistant CCC cells compared with the respective parental cells. Inhibition of mTORC2 during RAD001 treatment enhanced the antitumor effect of RAD001 and prevented CCC cells from acquiring resistance to RAD001. In conclusion, mTORC2 is frequently activated, and can be a promising therapeutic target, in ovarian CCCs. Moreover, mTORC2-targeted therapy may be efficacious in a first-line setting as well as for second-line treatment of recurrent disease developing after RAD001-treatment.

The activity of trabectedin as a single agent or in combination with everolimus for clear cell carcinoma of the ovary.

PURPOSE: The objective of this study was to evaluate the antitumor efficacy of trabectedin in clear cell carcinoma (CCC) of the ovary, which is regarded as an aggressive, chemoresistant, histologic subtype. EXPERIMENTAL DESIGN: Using 6 human ovarian cancer cell lines (3 CCC and 3 serous adenocarcinomas), the antitumor effects of trabectedin were examined in vitro, and we compared its activity according to histology. We next examined the antitumor activity of trabectedin in both cisplatin-resistant and paclitaxel-resistant CCC cells in vitro. Then, the in vivo effects of trabectedin were evaluated using mice inoculated with CCC cell lines. Using 2 pairs of trabectedin-sensitive parental and trabectedin-resistant CCC sublines, we investigated the role of mTOR in the mechanism of acquired resistance to trabectedin. Finally, we determined the effect of mTOR inhibition by everolimus on the antitumor efficacy of trabectedin in vitro and in vivo. RESULTS: Trabectedin showed significant antitumor activity toward chemosensitive and chemoresistant CCC cells in vitro. Mouse xenografts of CCC cells revealed that trabectedin significantly inhibits tumor growth. Greater activation of mTOR was observed in trabectedin-resistant CCC cells than in their respective parental cells. The continuous inhibition of mTOR significantly enhanced the therapeutic efficacy of trabectedin and prevented CCC cells from acquiring resistance to trabectedin. CONCLUSION: Trabectedin is a promising agent for CCC as a first-line chemotherapy and as a second-line treatment of recurrent CCC that had previously been treated with cisplatin or paclitaxel. Moreover, trabectedin combined with everolimus may be more efficacious for the management of CCC.