Therapeutic significance of targeting survivin in cervical cancer and possibility of combination therapy with TRAIL.

Loss of p53 function due to human papillomavirus (HPV) infection induces resistance to apoptosis in cervical cancer cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which induces apoptosis in a p53-independent manner, may provide an alternative strategy for treating cervical cancer. Survivin, an antiapoptotic protein that is highly expressed in cancer cells, regulates apoptosis and the cell cycle. Here, we investigated the therapeutic potential of targeting survivin, while focusing on the TRAIL-induced apoptosis pathway. The viability and cell cycle of HPV16-positive CaSki and SiHa cells were assessed after survivin knockdown by small interfering RNA (si-survivin). E-cadherin expression was also assessed after si-survivin treatment, using western blotting. SiHa (a TRAIL-resistant cell line) was used for further studies. The small molecule YM155 and resveratrol (RVT; a polyphenol with the potential to suppress survivin expression) were used as survivin inhibitors. The effects of si-survivin and survivin inhibitors on TRAIL- or cisplatin (CDDP)-induced apoptosis were analyzed by annexin-V staining. si-survivin treatment decreased cell viability and led to G2/M arrest, accompanied by morphological changes and E-cadherin upregulation in both CaSki and SiHa cells. si-survivin and YM155 synergistically sensitized TRAIL-resistant SiHa cells to TRAIL-induced apoptosis (p < 0.05). However, si-survivin and YM155 only slightly increased CDDP-induced apoptosis. RVT markedly enhanced TRAIL-induced apoptosis by suppressing survivin expression. Targeting of survivin expression might be an ideal strategy for cervical cancer treatment as it would decrease viable cell number and enhance apoptosis sensitivity. Further, combination therapy with TRAIL, rather than CDDP, may be compatible with the proposed survivin-targeting strategy.

Recent Progress in Therapeutics for Inflammation-Associated Preterm Birth: A Review.

Preterm birth is one of the most common obstetrical complications, with an incidence of about 5% to 18% of all pregnancies worldwide. Acute chorioamniotic infection is likely antecedent to preterm birth through the local production of inflammatory mediators, followed by uterine contraction and cervical ripening. Microbial chorioamnionitis and local inflammation synergistically form a vicious circle toward preterm birth. Principal therapeutic interventions focus on anti-infection and anti-inflammation strategies to block this vicious circle. Anti-inflammatory therapeutics include agents that directly inhibit inflammatory cytokine production/reaction and that resolve supraphysiological inflammation toward a normal condition. In particular, naturally produced compounds, including polyphenols, omega-3 polyunsaturated fatty acid metabolites, and statins, are attractive agents in terms of safety for pregnant women and their infants. This review summarizes the mechanisms of perinatal inflammation induced by acute chorioamnionitis and therapeutic resolution of inflammation of the uterus to avoid the harmful exposure of preterm infants to inflammation in utero.

STAT3 activity regulates sensitivity to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in cervical cancer cells.

In cervical cancer, p53-induced apoptosis is abrogated by human papilloma virus (HPV)-derived oncoprotein E6. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) provides tumor-specific apoptosis in various cancers, including cervical cancer, the sensitivity differs depending on the cell lines. Signal transducer and activator of transcription 3 (STAT3) is a hub molecule that shifts the cellular fate to apoptosis or survival in response to cellular stresses. However, the contribution of STAT3 activity to TRAIL-induced apoptosis in cervical cancer remains unknown. We examined the TRAIL sensitivity in cervical cancer cells, using TRAIL-resistant (SiHa) and -sensitive (CaSki) cervical cancer cell lines and focused on STAT3 function involving the apoptotic pathway. STAT3 was inactivated by TRAIL stimulation in the CaSki cell line, but not in the SiHa cell line. We then inhibited STAT3 expression in the SiHa cell line using siRNA against STAT3 and suppressed STAT3 activity using a STAT3 inhibitor; both these treatments sensitized TRAIL-induced apoptosis in the SiHa cell line. Furthermore, the SiHa cells were exposed to tunicamycin (TM), an endoplasmic reticulum (ER) stress inducer that inactivates STAT3, with or without TRAIL. Accompanied by STAT3 inactivation, TM pretreatment significantly enhanced TRAIL-induced apoptosis. We therefore concluded that TRAIL-induced apoptosis was regulated by STAT3 in response to TRAIL stimulation. Our results also suggest that STAT3 inhibition increases the sensitivity of malignancies, particularly HPV-related cancer, to TRAIL-based therapy.

Modification of the Tumor Microenvironment in KRAS or c-MYC-Induced Ovarian Cancer-Associated Peritonitis.

The most common properties of oncogenes are cell proliferation and the prevention of apoptosis in malignant cells, which, as a consequence, induce tumor formation and dissemination. However, the effects of oncogenes on the tumor microenvironment (TME) have not yet been examined in detail. The accumulation of ascites accompanied by chronic inflammation and elevated concentrations of VEGF is a hallmark of the progression of ovarian cancer. We herein demonstrated the mechanisms by which oncogenes contribute to modulating the ovarian cancer microenvironment. c-MYC and KRAS were transduced into the mouse ovarian cancer cell line ID8. ID8, ID8-c-MYC, or ID8-KRAS cells were then injected into the peritoneal cavities of C57/BL6 mice and the production of ascites was assessed. ID8-c-MYC and ID8-KRAS both markedly accelerated ovarian cancer progression in vivo, whereas no significant differences were observed in proliferative activity in vitro. ID8-KRAS in particular induced the production of ascites, which accumulated between approximately two to three weeks after the injection, more rapidly than ID8 and ID8-c-MYC (between nine and ten weeks and between six and seven weeks, respectively). VEGF concentrations in ascites significantly increased in c-MYC-induced ovarian cancer, whereas the concentrations of inflammatory cytokines in ascites were significantly high in KRAS-induced ovarian cancer and were accompanied by an increased number of neutrophils in ascites. A cytokine array revealed that KRAS markedly induced the expression of granulocyte macrophage colony-stimulating factor (GM-CSF) in ID8 cells. These results suggest that oncogenes promote cancer progression by modulating the TME in favor of cancer progression.

Resveratrol Protects Against Pathological Preterm Birth by Suppression of Macrophage-Mediated Inflammation.

Inflammatory cytokines play a major role in spontaneous preterm birth. Resveratrol has strong anti-inflammatory effects, but its effect on preterm birth in vivo is unknown. We investigated whether resveratrol protects against preterm birth in the lipopolysaccharide (LPS)-induced preterm mouse model. Twelve-day-old pregnant mice were fed 20 to 40 mg/kg resveratrol daily. On day 15, 10 µg of LPS was injected into uterine cervices. Resveratrol administration significantly decreased the rate of preterm birth. Resveratrol administration abolished LPS-induced elevation of tumor necrosis factor α (TNF-α) and interleukin (IL) 1ß but not IL-6 levels. The TNF-α messenger RNA levels were decreased in the cervices of resveratrol-administered mice compared with controls. Resveratrol treatment suppressed the elevation in TNF-α and IL-1ß levels in LPS-exposed peritoneal macrophages. Further resveratrol treatment eradicated the proinflammatory cytokine-mediated elevation in cyclooxygenase 2 (COX-2) in peritoneal macrophages. Resveratrol may protect against pathological preterm birth by suppression of elevated proinflammatory cytokines and consequent elevation of COX-2 in macrophages.

Increased tissue levels of omega-3 polyunsaturated fatty acids prevents pathological preterm birth.

Omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) have anti-inflammatory effects. Preterm birth is an important problem in modern obstetrics and one of the main causes is an inflammation. We here showed that abundance of omega-3 fatty acids reduced the incidence of preterm birth induced by LPS with fat-1 mice, capable of converting omega-6 to omega-3 fatty acids. We also indicated that the gene expression of IL-6 and IL-1ß in uteruses and the number of cervical infiltrating macrophages were reduced in fat-1 mice. The analyses of lipid metabolomics showed the high level of 18-hydroxyeicosapentaenoate in fat-1 mice, which was derived from EPA and was metabolized to anti-inflammatory product named resolvin E3 (RvE3). We finally showed that the administration of RvE3 to LPS-exposed pregnant wild type mice lowered the incidence of preterm birth. Our data suggest that RvE3 could be a potential new therapeutic for the prevention of preterm birth.