Combined use of NK cells and radiotherapy in the treatment of solid tumors.

Natural killer (NK) cells are innate lymphocytes possessing potent tumor surveillance and elimination activity. Increasing attention is being focused on the role of NK cells in integral antitumor strategies (especially immunotherapy). Of note, therapeutic efficacy is considerable dependent on two parameters: the infiltration and cytotoxicity of NK cells in tumor microenvironment (TME), both of which are impaired by several obstacles (e.g., chemokines, hypoxia). Strategies to overcome such barriers are needed. Radiotherapy is a conventional modality employed to cure solid tumors. Recent studies suggest that radiotherapy not only damages tumor cells directly, but also enhances tumor recognition by immune cells through altering molecular expression of tumor or immune cells via the in situ or abscopal effect. Thus, radiotherapy may rebuild a NK cells-favored TME, and thus provide a cost-effective approach to improve the infiltration of NK cells into solid tumors, as well as elevate immune-activity. Moreover, the radioresistance of tumor always hampers the response to radiotherapy. Noteworthy, the puissant cytotoxic activity of NK cells not only kills tumor cells directly, but also increases the response of tumors to radiation via activating several radiosensitization pathways. Herein, we review the mechanisms by which NK cells and radiotherapy mutually promote their killing function against solid malignancies. We also discuss potential strategies harnessing such features in combined anticancer care.

Loss of Heterozygosity for KrasG12D Promotes Malignant Phenotype of Pancreatic Ductal Adenocarcinoma by Activating HIF-2α-c-Myc-Regulated Glutamine Metabolism.

Loss of heterozygosity (LOH) for KRAS, in which a wild-type KRAS allele is progressively lost, promotes invasive and migratory abilities of pancreatic ductal adenocarcinoma (PDAC) cells and tissues. Moreover, the occurrence of KrasG12D-LOH activates nonclassical glutamine metabolism, which is related to the malignant behavior of PDAC cells. Herein, we aim to demonstrate the regulatory link between hypoxia-inducible factor-2α (HIF-2α) and glutamine metabolism that mediates malignant phenotypes in KrasG12D-LOH PDAC cells. HIF-2α-shRNA knockdown lentivirus transfection and metabolite analysis were performed in KrasG12D-LOH and KrasG12D cell lines, respectively. Cell proliferation, migration, and invasion were examined using Cell Counting Kit-8, colony formation, and Transwell assays. Cell cycle phase and apoptosis were determined using flow cytometry. Western blotting and real-time quantitative PCR were also performed. Additionally, a subcutaneous xenograft mouse model was established. LOH stimulated HIF-2α activity and transactivated c-Myc, which has a central regulatory effect on glutamine metabolism independent of hypoxia. Meanwhile, HIF-2α silencing repressed KrasG12D-LOH PDAC cell proliferation, invasion, and migration. HIF-2α knockdown inhibited glutamine uptake and GOT1 expression via a c-Myc-dependent pathway. Collectively, KrasG12D-LOH can activate HIF-2α to regulate c-Myc-mediated glutamine metabolism and promote malignant phenotypes. Moreover, targeting HIF-2α-c-Myc regulated nonclassical glutamine metabolism, providing a new therapeutic perspective for KrasG12D-LOH PDAC.

Significant Gene Biomarker Tyrosine Kinase Non-receptor 2 Mediated Cell Proliferation and Invasion in Colon Cancer.

Objective: This study aimed to investigate the expression and biological functions of TNK2 and miR-125a-3p in colon cancer. Materials and methods: The expression of TNK2 and miR-125a-3p in colon cancer tissues was analyzed using data deposited on public databases including UALCAN and ONCOMINE. We verified their expression in colon cancer cell lines by RT-qPCR and western blotting. By regulating the expression of TNK2 and miR-125a-3p in colon cancer cells, their functions and potential mechanisms were explored. Results: TNK2 was overexpressed in colon cancer cell lines, and it was found to directly bind to miR-125a-3p, which was downregulated in these cell lines. Their expression affected the proliferation and invasion of colon cancer cells. Additionally, colon cancer patients with lower TNK2 expression had better prognoses than those with higher TNK2 expression. Conclusion: Our results indicated that TNK2 and miR-125a-3p play critical roles in colon cancer, and could also serve as biomarkers for the diagnosis and prognosis of this malignant disease.

SLC7A5 serves as a prognostic factor of breast cancer and promotes cell proliferation through activating AKT/mTORC1 signaling pathway.

BACKGROUND: The purpose of our research was to determine if the clinical, pathological, and prognostic functions of SLC7A5 are the same as those of other molecular breast cancer (BC) subgroups. METHODS: We used the Oncomine and The Cancer Genome Atlas (TCGA) online databases to examine the expression and genetic changes of SLC7A5 in BC tissues. Immunohistochemical analysis was used to validate the SLC7A5 protein expression in subtypes of BC, while Kaplan-Meier figures and log-rank tests were used to evaluate the prognostic relevance of SLC7A5. Uni- and multivariate Cox regression models were adapted to analyze hazard ratios (HRs) and the independent prognostic factors. We analyzed the alterations of different malignancies of luminal cells by up-regulation of SLC7A5 in human luminal cell lines MCF-7. SLC7A5 was overexpressed in luminal cells, and then the AKT, mTOR, and p70-S6K phosphorylation and expression were analyzed by western blot analysis and real-time quantitative polymerase chain reaction (qPCR). RESULTS: Our results suggested that SLC7A5 was overexpressed in BC cell lines and in patients' tissues. Elevated SLC7A5 messenger RNA (mRNA) and SLC7A5 protein expression was correlated to a worse clinical prognosis (P<0.001) in luminal subtypes of BC. The multivariate analysis suggested that high level of SLC7A5 expression could be an independent prognostic factor for decreased overall survival (OS). The study also demonstrated that SLC7A5 overexpression increased proliferation of MCF-7 cells by reducing the cell cycle arrest in G1 phase. Our mechanistic study further indicates that SLC7A5 enhances the proliferation of the MCF-7 cell by activation of AKT/mTORC1 pathway through phosphorylation. CONCLUSIONS: Our study demonstrated that SLC7A5 may have a vital function in the biology of BC cells, indicating that SLC7A5 is a potential prognostic biomarker and may be a valuable therapeutic target in BC patients.

MiR-15a Functions as a Diagnostic Biomarker for Coronary Artery Disease.

BACKGROUND: The present study aimed to explore the diagnostic value of miR-15a in coronary artery disease (CAD). METHODS: After recruiting all the participants, peripheral blood samples were obtained according to the instructions. miR-15a expression was evaluated using real-time quantitative polymerase chain reaction (RT-qPCR) and IL-6, TNF-α, and hs-CRP expressions were detected using ELISA kits. RESULTS: The results elucidated a significantly decreased expression of miR-15a in peripheral blood samples from CAD patients compared to non-CAD controls (p < 0.01). Meanwhile, miR-15a expression was negatively correlated with LDL-C and Gensini score (p = 0.0059, 0.0243, respectively). Moreover, miR-15a expression was negatively correlated with inflammatory cytokines IL-6, TNF-α, and hs-CRP (p = 0.0009, 0.0178, 0.0005, respectively). The receiver operating curve (ROC) curve analysis demonstrated that miR-15a was a promising biomarker for early diagnosis of CAD with an area under the curve (AUC) of 0.9368. CONCLUSIONS: The present study elucidated a decreased miR-15a expression in CAD patients and showed negative correlations with LDL-C, Gensini score, and inflammatory cytokines. miR-15a may serve as a promising biomarker for early diagnosis of CAD.

CircRHOT1 mediated cell proliferation, apoptosis and invasion of pancreatic cancer cells by sponging miR-125a-3p.

Pancreatic cancer patients are asymptomatic at early stages and leading to late diagnoses. Additionally, pancreatic cancer easily metastasizes and is resistant to radiotherapy and chemotherapy. Therefore, it is critical to understand the underlying molecular mechanisms involved in pancreatic cancer to develop more efficient diagnostic and treatment strategies. In this study, we demonstrated that circRHOT1 was overexpressed in pancreatic cancer tissues and cell lines, and it was found to directly bind to miR-125a-3p, acting as an endogenous sponge to inhibit its activity. Knockdown of circRHOT1 expression significantly inhibited proliferation as well as invasion, and it promoted apoptosis of pancreatic cancer cells via the regulation of E2F3 through the targeting of miR-125a-3p. Taken together, our results showed that circRHOT1 plays critical roles in regulating the biological functions of pancreatic cancer cells, suggesting that circRHOT1 may serve as a potential diagnostic marker and therapeutic target for patients with pancreatic cancer.

Loss of heterozygosity for KrasG12D promotes REDD1-dependent, non-canonical glutamine metabolism in pancreatic ductal adenocarcinoma.

Pancreatic cancer is associated with high mortality, and pancreatic ductal adenocarcinoma (PDAC) is its most common subtype. The rapid growth of PDAC is dependent on the non-canonical pathway of glutamine (Gln) utilization, and loss of heterozygosity for KrasG12D (KrasG12D-LOH) frequently observed in PDAC is associated with an aggressive and invasive phenotype. However, it remains unclear whether KrasG12D-LOH contributes to non-canonical Gln metabolism in PDAC. Here, we showed that KrasG12D-LOH leads to a substantial increase in non-canonical Gln metabolism in PDAC cells. Importantly, we observed elevated expression of regulated in DNA damage and development 1 (REDD1), which is activated in response to hypoxia and nutrient deprivation, in KrasG12D-LOH PDAC, and that REDD1 knockdown efficiently repressed KrasG12D-LOH-regulated Gln metabolism and suppressed proliferation, migration, and invasion of KrasG12D-LOH PDAC cells. These data provide evidence that REDD1 is a downstream target of KrasG12D-LOH and is involved in promoting non-canonical Gln metabolism in PDAC.

Protective effects of acarbose against vascular endothelial dysfunction through inhibiting Nox4/NLRP3 inflammasome pathway in diabetic rats.

The cardiovascular efficacy of glucose-lowering drugs is needed due to the cardiovascular complication in type 2 diabetes mellitus (T2DM). Acarbose is an α-glucosidase inhibitor that suppresses postprandial hyperglycemia, however, the cardiovascular protection of acarbose has still remained controversial. NLRP3 inflammasome activation mediated tight junction disruption, a hallmark event of endothelial barrier dysfunction leading to endothelial hyperpermeability in diabetes. Given the anti-inflammatory property of acarbose, it was investigated that acarbose protected against vascular endothelial barrier dysfunction through inhibiting NLRP3 inflammasome in vascular endothelial cells in T2DM rats. The rat aortic endothelial cells (RAECs) were incubated with high glucose (HG, 30 mM) for 24 h in vitro. It was found that HG significantly induced the formation and activation of NLRP3 inflammasome, which was markedly blocked by acarbose treatment. Furthermore, acarbose blocked the Nox4-dependent superoxide (O2.-) generation, which regulated NLRP3 inflammasome in RAECs. Importantly, we found that acarbose remarkably enhanced the junction protein expression of ZO-1 and VE-Cadherin and consequently abolished vascular hyperpermeability, which was associated with inhibiting NLRP3 inflammasome in RAECs. In vivo, acarbose intervention relieved vascular leakage in the heart of diabetic rats injected with Evans blue dye and the vasodilatory response to acetylcholine, which was accompanied with the restoration of ZO-1, VE-Cadherin, Nox4 and NLRP3 inflammasome in the aortal endothelium of diabetic rats. Taken together, our data indicated that acarbose ameliorated endothelial barrier dysfunction by directly inhibiting NLRP3 inflammasome which was dependent on inhibiting Nox4 oxidase-dependent O2.- production. These properties might carry a potential significance for acarbose in cardiovascular protection in diabetic patients.

Long non-coding RNA HOTAIR promotes cancer cell energy metabolism in pancreatic adenocarcinoma by upregulating hexokinase-2.

Hox transcript antisense RNA (HOTAIR) is a long non-coding RNA (lncRNA) that serves a key role in the pathogenesis of various types of cancer, including pancreatic adenocarcinoma. However, the diagnostic and prognostic values of HOTAIR in pancreatic adenocarcinoma, as well as its involvement in cancer cell energy metabolism, remain unclear. In the present study, tumor tissues and adjacent healthy tissues were collected from patients with pancreatic adenocarcinoma, and blood samples were collected from patients and healthy controls. Expression levels of HOTAIR and hexokinase-2 (HK2) were detected by reverse transcription-quantitative polymerase chain reaction. All patients were followed up for 5 years, and the diagnostic and prognostic values of serum HOTAIR levels were investigated by receiver operating characteristic curve and survival analyses, respectively. Pancreatic adenocarcinoma cell lines overexpressing HOTAIR and HK2 were established, and the effects on cell proliferation, lactate production, glucose uptake and ATP production were detected by Cell Counting Kit-8, lactate, glucose uptake and ATP assays, respectively. The protein expression was detected by western blot analysis. The results revealed that HOTAIR and HK2 expression levels were increased in tumor tissues compared with adjacent healthy tissues. The serum levels of HOTAIR and HK2 were higher in patients with pancreatic cancer compared with healthy controls. The serum levels of these two factors may be used to accurately predict pancreatic adenocarcinoma and its prognosis. HOTAIR and HK2 overexpression led to the promotion of tumor cell proliferation. HOTAIR overexpression increased lactate production, glucose uptake and ATP production. Furthermore, it promoted HK2 expression, however HK2 overexpression displayed no significant effects on HOTAIR expression levels. Therefore, it was concluded that the lncRNA HOTAIR may promote cancer cell energy metabolism in pancreatic adenocarcinoma by upregulating HK2.

DNA methylation regulates α-smooth muscle actin expression during cardiac fibroblast differentiation.

Cardiac fibroblast (CF) differentiation to myofibroblasts expressing α-smooth muscle actin (α-SMA) plays a key role in cardiac fibrosis. Therefore, a study of the mechanism regulating α-SMA expression is a means to understanding the mechanism of fibroblast differentiation and cardiac fibrosis. Previous studies have shown that DNA methylation is associated with gene expression and is related to the development of tissue fibrosis. However, the mechanisms by which CF differentiation is regulated by DNA methylation remain unclear. Here, we explored the epigenetic regulation of α-SMA expression and its relevance in CF differentiation. In this study, we demonstrated that α-SMA was overexpressed and DNMT1 expression was downregulated in the infarct area after myocardial infarction. Treatment of CFs with transforming growth factor-ß1 (TGF-ß1 ) in vitro upregulated α-SMA expression via epigenetic modifications. TGF-ß1 also inhibited DNMT1 expression and activity during CF differentiation. In addition, α-SMA expression was regulated by DNMT1. Conversely, increasing DNMT1 expression levels rescued the TGF-ß1 -induced upregulation of α-SMA expression. Finally, TGF-ß1 regulated α-SMA expression by inhibiting the DNMT1-mediated DNA methylation of the α-SMA promoter. Taken together, our research showed that inhibition of the DNMT1-mediated DNA methylation of the α-SMA promoter plays an essential role in CF differentiation. In addition, DNMT1 may be a new target for the prevention and treatment of myocardial fibrosis.

Dietary fiber intake and risks of proximal and distal colon cancers: A meta-analysis.

The purpose of this study was to conduct a systematic review and meta-analysis of studies investigating the relationship between dietary fiber intake and subsite-specific colon cancer.The PubMed database was searched to identify relevant cohort studies published from inception to August 2016 in order to examine individually the association between dietary fiber intake and the risk of proximal colon cancer (PCC), and that between dietary fiber intake and the risk of distal colon cancer (DCC). We searched the reference lists of the studies included in our analysis as well as those listed in the published meta-analyses. A random-effects model was used to compute summary risk estimates. Heterogeneity was assessed using I and Q statistics. Publication bias was assessed with the Egger's and Begg's tests, with a P value of P < .10 indicating publication bias. All statistical tests were 2-sided.We identified and included 11 prospective cohort studies in the final meta-analysis. The risks of PCC and DCC among individuals in the highest dietary fiber intake quartile/quintile were 14% (relative risk [RR] = 0.86, 95% confidence interval [CI] = 0.78-0.95) and 21% (RR = 0.79, 95% CI = 0.71-0.87) lower, respectively, than those among individuals with the lowest dietary fiber intake. In a subgroup analysis, the inverse association observed in the sex-based subgroup was apparent only for men with PCC. Dietary fiber intake was inversely associated with DCC for both men and women. In addition, dietary fiber intake appeared to be inversely associated with PCC only in European countries, whereas this association was observed for DCC in both European countries and the United States.Our findings reveal that dietary fiber intake is associated inversely with the risk of both PCC and DCCs.