Immune checkpoint blockade of the inhibitory immune receptors PD-L1, PD-1 and CTLA-4 has emerged as a successful treatment strategy for several advanced cancers. Here we demonstrate that miR-424(322) regulates the PD-L1/PD-1 and CD80/CTLA-4 pathways in chemoresistant ovarian cancer. miR-424(322) is inversely correlated with PD-L1, PD-1, CD80 and CTLA-4 expression. High levels of miR-424(322) in the tumours are positively correlated with the progression-free survival of ovarian cancer patients. Mechanistic investigations demonstrated that miR-424(322) inhibited PD-L1 and CD80 expression through direct binding to the 3′-untranslated region. Restoration of miR-424(322) expression reverses chemoresistance, which is accompanied by blockage of the PD-L1 immune checkpoint. The synergistic effect of chemotherapy and immunotherapy is associated with the proliferation of functional cytotoxic CD8+ T cells and the inhibition of myeloid-derived suppressive cells and regulatory T cells. Collectively, our data suggest a biological and functional interaction between PD-L1 and chemoresistance through the microRNA regulatory cascade.

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Phenolic estrogen pollutants, a class of typical endocrinedisrupting chemicals, have attracted public attention due to their estrogenic activities of imitating steroid hormone 17b-estradiol (E 2 ) effects. Exposure to these pollutants may disrupt insulin secretion and be a risk factor for type 2 diabetes. In this study, we investigated the direct effects of phenolic estrogen diethylstilbestrol (DES), octylphenol (OP), nonylphenol (NP), and bisphenol A (BPA) on rat pancreatic islets in vitro, whose estrogenic activities were DESONPOOPOBPA. Isolated b-cells were exposed to E 2 , DES, OP, NP, or BPA (0, 0 . 1, 0 . 5, 2 . 5, 25, and 250 mg/l) for 24 h. Parameters of insulin secretion, content, and morphology of b-cells were measured. In the glucose-stimulated insulin secretion test, E 2 and DES increased insulin secretion in a dose-dependent manner in a 16 . 7 mM glucose condition. However, for BPA, NP, or OP with lower estrogenic activity, the relationship between the doses and insulin secretion was an inverted U-shape. Moreover, OP, NP, or BPA (25 mg/l) impaired mitochondrial function in b-cells and induced remarkable swelling of mitochondria with loss of distinct cristae structure within the membrane, which was accompanied by disruption of mRNA expression of genes playing a key role in b-cell function (Glut2 (Slc2a2), Gck, Pdx1, Hnf1a, Rab27a, and Snap25), and mitochondrial function (Ucp2 and Ogdh). Therefore, these phenolic estrogens can disrupt islet morphology and b-cell function, and mitochondrial dysfunction is suggested to play an important role in the impairment of b-cell function.

Prostate cancer at advanced stages including metastatic and castration-resistant cancer remains incurable due to the lack of effective therapies. The CAMK2N1 gene, cloned and characterized as an inhibitor of CaMKII (calcium/calmodulin-dependent protein kinase II), has been shown to affect tumorigenesis and tumor growth. However, it is still unknown whether CAMK2N1 plays a role in prostate cancer development. We first examined the protein and mRNA levels of CAMK2N1 and observed a significant decrease in human prostate cancers comparing to normal prostate tissues. Re-expression of CAMK2N1 in prostate cancer cells reduced cellular proliferation, arrested cells in G0/G1 phases, and induced apoptotic cell death accompanied by down-regulation of IGF-1, ErbB2, and VEGF downstream kinases PI3K/AKT, as well as the MEK/ERK-mediated signaling pathways. Conversely, knockdown of CAMK2N1 had a significant opposite effects on these phenotypes. Our analyses suggest that CAMK2N1 plays a tumor suppressive role in prostate cancer cells. Reduced CAMK2N1 expression correlates to human prostate cancer progression and predicts poor clinical outcome, indicating that CAMK2N1 may serve as a biomarker. The inhibition of tumor growth by expressing CAMK2N1 established a role of CAMK2N1 as a therapeutic target.

Castration resistance is a major obstacle to hormonal therapy for prostate cancer patients. Although androgen independence of prostate cancer growth is a known contributing factor to endocrine resistance, the mechanism of androgen receptor deregulation in endocrine resistance is still poorly understood. Herein, the CAMK2N1 was shown to contribute to the human prostate cancer cell growth and survival through AR-dependent signaling. Reduced expression of CAMK2N1 was correlated to recurrence-free survival of prostate cancer patients with high levels of AR expression in their tumor. CAMK2N1 and AR signaling form an auto-regulatory negative feedback loop: CAMK2N1 expression was down-regulated by AR activation; while CAMK2N1 inhibited AR expression and transactivation through CAMKII and AKT pathways. Knockdown of CAMK2N1 in prostate cancer cells alleviated Casodex inhibition of cell growth, while re-expression of CAMK2N1 in castration-resistant cells sensitized the cells to Casodex treatment. Taken together, our findings suggest that CAMK2N1 plays a tumor suppressive role and serves as a crucial determinant of the resistance of prostate cancer to endocrine therapies.

Abstract. Long non-coding RNAs (lncRNAs) have previously been reported to be involved in cancer invasion, proliferation and apoptosis. However, the association between the lncRNA, H19, and esophageal cancer (EC) has remained elusive. In the present study, reverse transcription quantitative-polymerase chain reaction revealed that the expression of H19 was significantly increased and associated with tumor depth and metastasis in 133 EC samples. Furthermore, MTT and Transwell assays revealed that overexpression of H19 in vitro promoted the proliferation and invasion of EC cell lines, whereas knockdown of H19 inhibited the proliferation and invasion of EC cell lines. In addition, it was identified that an upregulation of H19 induced epithelial-to-mesenchymal transition, while the opposite effect was observed following the downregulation of H19. In conclusion, H19 has a significant role in the development of EC and may serve as a potential prognostic marker and therapeutic target for EC. IntroductionEsophageal carcinoma (EC) is the eighth most aggressive and malignant type of cancer, with a high incidence that varies according to geographic location and ethnicity (1). Despite progress in the development of diagnostic and therapeutic options, the survival rates for EC patients remain poor. Therefore, the identification of novel genes involved in the tumorigenesis and development of EC is urgently required.Long non-coding RNAs (lncRNAs) are a class of RNAs that have been reported to be involved in the regulation, invasion, proliferation and apoptosis of multiple tumors (2,3). The association between H19 expression and the progression of various types of cancer has been demonstrated in previous studies. One study found that the overexpression of lncRNA H19 enhanced the carcinogenesis and metastasis of gastric cancer (4). MALAT-1, an abundant lncRNA present in many human cell types, has been suggested to regulate the alternative splicing of a subset of pre-messenger (m)RNAs by modulating serine/arginine splicing factor activity. This factor in turn regulates tissue or cell-type-specific alternative splicing in a phosphorylation-dependent manner (5). However, the role of H19 in EC is yet to be elucidated.The epithelial-to-mesenchymal transition (EMT) has an important role in the invasion of various types of cancer by transforming adherent and polarized epithelial cells into invasive and motile mesenchymal cells (6,7). A number of transcription factors involved in EMTs, including Twist and Snail, increase the expression level of mesenchymal markers, including fibronectin, collagen and Vimentin, and decrease the expression of epithelial markers, including E-cadherin. The breakdown of tight junctions results in the loss of epithelial markers and the acquisition of mesenchymal markers (8-10).In the present study, the expression levels of H19 in EC were investigated, in order to elucidate the role of H19 in EC. Materials and methods Clinical

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This study was performed as part of a doctoral dissertation by the senior author at the California Institute of Technology (Caltech). Work was supported by the U.S. Department of Energy through BES-Material Sciences Contract W-31-109-ENG-38 to Argonne National Laboratory and BES-Engineering and Geosciences Grant DE-FG03-88ER13851 to Caltech. Caltech Division of Geological and Planetary Sciences Contribution Number 4759 (675).