SUSD2 suppresses CD8+ T cell antitumor immunity by targeting IL-2 receptor signaling.

Dysfunctional CD8+ T cells, which have defective production of antitumor effectors, represent a major mediator of immunosuppression in the tumor microenvironment. Here, we show that SUSD2 is a negative regulator of CD8+ T cell antitumor function. Susd2-/- effector CD8+ T cells showed enhanced production of antitumor molecules, which consequently blunted tumor growth in multiple syngeneic mouse tumor models. Through a quantitative mass spectrometry assay, we found that SUSD2 interacted with interleukin (IL)-2 receptor α through sushi domain-dependent protein interactions and that this interaction suppressed the binding of IL-2, an essential cytokine for the effector functions of CD8+ T cells, to IL-2 receptor α. SUSD2 was not expressed on regulatory CD4+ T cells and did not affect the inhibitory function of these cells. Adoptive transfer of Susd2-/- chimeric antigen receptor T cells induced a robust antitumor response in mice, highlighting the potential of SUSD2 as an immunotherapy target for cancer.

Comparison of 2013 and 2009 versions of Caprini risk assessment models for predicting VTE in Chinese cancer patients: a retrospective study.

This study aimed to compare the predictive value of 2009 and 2013 version of Caprini risk assessment models (RAM) for venous thromboembolism (VTE) in cancer patients by receiver operating characteristic (ROC) analysis. This retrospective study reviewed a total of 1439 VTE and 1439 non-VTE Chinese cancer inpatients. The baseline demographic data of these patients were recorded. 2009 and 2013 versions Caprini RAMs were applied, and cumulative risk scores were obtained by adding the scores of each risk factor. The specificity, sensitivity, positive predictive value and negative predictive value of these two models were analyzed. ROC curve was drawn to calculate the area under the curve (AUC) and the Youden index. Significant differences were observed in the risk factors between VTE and non-VTE Group. The specificity and negative predictive value of 2013 version were higher than those of 2009 version (P < 0.05). No significant differences were found in the sensitivity or positive predictive value between 2009 and 2013 versions of the Caprini RAM (P > 0.05). The AUC and Youden index of 2013 Caprini RAM were significantly higher than those of 2009 Caprini RAM (P < 0.001), whereas the Youden index of the 2009 Caprini RAM at critical point 4 was higher than that at critical point 3 (0.362 vs 0.067, P < 0.05). Compared with 2009 version, 2013 version of the Caprini RAM provides a more accurate and efficacious method for the risk assessment of VTE in Chinese cancer patients.

After neoadjuvant chemotherapy platelet/lymphocyte ratios negatively correlate with prognosis in gastric cancer patients.

INTRODUCTION: Circulating predictors prognostic factors of neoadjuvant chemotherapy, which identify the patients who are potential possibly to benefit from it are limited at present. In this research, we aimed to compare the prognostic significance of neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) in patients with locally advance gastric carcinoma who were treated with neoadjuvant chemotherapy (NAC) followed by D2 gastrectomy. MATERIALS AND METHODS: From 2007 to 2015, 91 patients with locally advanced gastric cancer treated with NAC followed by D2 gastrectomy included in this retrospective cohort study. The correlation of clinical data, including tumor regression, response evaluation, tumor location, pathological type, systemic therapy, tumor size (cm), neural invasion, lymphatic-vascular invasion, ypTNM stage, and survival prognosis were analyzed. RESULTS: Platelet/lymphocyte ratio and neutrophil/lymphocyte ratio in gastric cancer patients were higher than in matched normal volunteers. PLR levels higher after neoadjuvant chemotherapy are associated with worse OS. Multivariate Cox proportional analysis showed that pre-neoadjuvant chemotherapy PLR was an independent prognostic factor. CONCLUSIONS: Pre-neoadjuvant chemotherapy PLR may be a feasible biomarker for survival prognosis in patients with locally advanced gastric cancer. PLR and NLR were reduced after neoadjuvant chemotherapy. After neoadjuvant chemotherapy, PLR level was negatively correlated with survival prognosis.

[Phosphorylation status of ASPP2 modulates p53 apoptotic function in oxaliplatin-induced apoptosis of colorectal cancer HCT116 cells].

OBJECTIVE: To investigate the role of apoptosis stimulating protein 2 of p53 (ASPP2) phosphorylation status in the regulation of ASPP2-p53 apoptotic pathway activity. METHODS: Cells were individually transfected with green fluorescent protein (GFP)-encoding vector, constitutively non-phosphorylatable ASPP2 mutant-ASPP2 (Am)-encoding vector, and wild type ASPP2 (Aw)-encoding vector) plasmids, respectively, to make them overexpressing phosphorylated and non-phosphorylated ASPP2 proteins, respectively. Cell apoptosis was induced by oxaliplatin. The apoptosis rate of cells was determined by flow cytometry after staining with FITC-conjugated annexin V and PI. ASPP2 protein level and its phosphorylation status were observed by Western blot. The interaction between ASPP2 and p53 was observed by immunoprecipitation assay. RESULTS: Oxaliplatin induced cell apoptosis and caused phosphorylation of ASPP2 at ser92/ser361 in the HCT116 cells. The apoptosis rate of Aw and Am plasmids-transfected cells were (3.8 ± 1.0)% and (3.9 ± 1.2)% respectively, statistically with a non-significant difference (P > 0.05) in comparison with that of the GFP plasmid-transfected cells [(4.0 ± 0.8)%]. After oxaliplatin treatment, the apoptosis rate of Aw plasmid-transfected cells was (46.7 ± 3.9)%, significantly higher than that of the Am and GFP plasmid-transfected cells [(40.1 ± 10.2)% and (37.1 ± 6.9)%, respectively, P < 0.05], however, there was no statistically significant difference (P > 0.05) between Am and GFP plasmid-transfected cells. These results indicate that phosphorylated ASPP2 promoted the oxaliplatin-induced apoptosis of HCT116 cells through a p53-dependent pathway. Phosphorylation status of ASPP2 influenced its binding activity to p53. CONCLUSION: Phosphorylation status of ASPP2 modulates p53 apoptotic function in oxaliplatin-induced apoptosis of colorectal cancer HCT116 cells.

YB1 participated in regulating mitochondrial activity through RNA replacement.

As a relic of ancient bacterial endosymbionts, mitochondria play a central role in cell metabolism, apoptosis, autophagy, and other processes. However, the function of mitochondria-derived nucleic acids in cellular signal transduction has not been fully elucidated. Here, our work has found that Y-box binding protein 1 (YB1) maintained cellular autophagy at a moderate level to inhibit mitochondrial oxidative phosphorylation. In addition, mitochondrial RNA was leaked into cytosol under starvation, accompanied by YB1 mitochondrial relocation, resulting in YB1-bound RNA replacement. The mRNAs encoded by oxidative phosphorylation (OXPHOS)-associated genes and oncogene HMGA1 (high-mobility group AT-hook 1) were competitively replaced by mitochondria-derived tRNAs. The increase of free OXPHOS mRNAs released from the YB1 complex enhanced mitochondrial activity through facilitating translation, but the stability of HMGA1 mRNA was impaired without the protection of YB1, both contributing to breast cancer cell apoptosis and reactive oxygen species production. Our finding not only provided a new potential target for breast cancer therapy but also shed new light on understanding the global landscape of cellular interactions between RNA-binding proteins and different RNA species.

METTL3 promotes colorectal cancer progression through activating JAK1/STAT3 signaling pathway.

The role of METTL3-mediated N6-methyladenosine (m6A) modification has been elucidated in several cancers, but the concrete mechanism underlying its function in colorectal cancer is still obscure. Here, we revealed that upregulated methyltransferase-like 3 (METTL3) in colorectal cancer exerted both methyltransferase activity-dependent and -independent functions in gene regulation. METTL3 deposited m6A on the 3' untranslated region of the JAK1 transcript to promote JAK1 translation relying on YTHDF1 recognition. Besides, METTL3 was redistributed to the STAT3 promoter and worked in concert with NF-κB to facilitate STAT3 transcription, which was achieved independently on METTL3 methyltransferase activity. The increased JAK1 and STAT3 corporately contributed to the activation of the p-STAT3 signaling pathway and further upregulated downstream effectors expressions, including VEGFA and CCND1, which finally resulted in enhanced cancer cell proliferation and metastasis in vitro and in vivo. Collectively, our study revealed the unappreciated dual role of METTL3 as an m6A writer and a transcription regulator, which worked together in the same signaling pathway to drive colorectal cancer malignancy.

SHF confers radioresistance in colorectal cancer by the regulation of mitochondrial DNA copy number.

Altered mitochondrial function contributes greatly to pathogenesis and progression of colorectal cancer. In this study, we report a functional pool of Src homology 2 domain-containing F (SHF) in mitochondria controlling the response of colorectal cancer cells to radiation therapy. We found that elevated expression of SHF in cancer cells is essential for promoting mitochondrial function by increasing mitochondrial DNA copy number, thus reducing the sensitivity of colorectal cancer cells to radiation. Mechanistically, SHF binds to mitochondrial DNA and promotes POLG/SSBP1-mediated mitochondrial DNA synthesis. Importantly, SHF loss-mediated radiosensitization was phenocopied by depletion of mitochondrial DNA. Thus, our data demonstrate that mitochondrial SHF is an important regulator of radioresistance in colorectal cancer cells, identifying SHF as a promising therapeutic target to enhance radiotherapy efficacy in colorectal cancer.

A novel mitochondria-related gene signature for controlling colon cancer cell mitochondrial respiration and proliferation.

Colon cancer cells rely on mitochondrial respiration as major source of energy for supporting their proliferation and invasion, thus promoting colon cancer malignancy and progression. In this study, we comprehensively investigated the prognostic significance of mitochondria-related genes in colon cancer and identified the hub genes that control colon cancer cell mitochondrial respiration and proliferation. We first systematically evaluated the prognostic significance of differentially expressed mitochondria-related genes in colon cancer specimens. Furthermore, a protein-protein interaction network was constructed to explore the hub genes. Eventually, five hub genes were identified, namely, POLG, FASTK, MRPS5, AARS2, and VARS2. Functional analyses showed that all these five hub genes are essential for maintaining mitochondrial respiration and proliferation of colon cancer cells. Mechanistic studies revealed the roles of these five hub genes in modulating mitochondrial DNA expression, that in turn influence mitochondrial respiration. In summary, our study demonstrated that POLG, FASTK, MRPS5, AARS2, and VARS2 may potentially serve as prognostic biomarkers and therapeutic targets for colon cancer.

FKBP4 regulates 5-fluorouracil sensitivity in colon cancer by controlling mitochondrial respiration.

Mitochondrial respiration and metabolism play a key role in the pathogenesis and progression of colon adenocarcinoma (COAD). Here, we report a functional pool of FKBP4, a co-chaperone protein, in the mitochondrial intermembrane space (IMS) of colon cancer cells. We found that IMS-localized FKBP4 is essential for the maintenance of mitochondrial respiration, thus contributing to the sensitivity of COAD cells to 5-fluorouracil (5-FU). Mechanistically, FKBP4 interacts with COA6 and controls the assembly of the mitochondrial COA6/SCO1/SCO2 complex, thereby governing COA6-regulated biogenesis and activity of mitochondrial cytochrome c oxidase (complex IV). Thus, our data reveal IMS-localized FKBP4 as a novel regulator of 5-FU sensitivity in COAD, linking mitochondrial respiration to 5-FU sensitivity in COAD.

Revealing potential immunotherapy targets through analysis of a ceRNA network in human colon adenocarcinoma.

BACKGROUND: Microsatellite instability-high (MSI-H) is a special type of human colon adenocarcinoma (COAD) that responds well to immunotherapy. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs), which are important members of competing endogenous RNAs (ceRNAs) networks, are involved in the tumorigenesis and development of MSI-H COAD. This study aimed to establish a ceRNA network for MSI in COAD to identify targets and prognostic markers that may explain the effects of immunotherapy. METHODS: COAD sequencing data were extracted from The Cancer Genome Atlas (TCGA), after which differentially expressed miRNAs, lncRNAs, and mRNAs were determined according to microsatellite status. After building a network based on the ceRNA hypothesis, the relationships between microsatellite status and clinical features were explored. Biological processes in the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were analyzed for specific miRNAs, lncRNAs, and mRNAs. Survival analysis was used to identify potential biomarkers. RESULTS: Based on the inclusion criteria, a total of 363 COAD samples were obtained from TCGA. Strict screening criteria were used to identify differentially expressed RNAs in the MSI-H and microsatellite-stable groups, with 82 miRNAs, 1,280 lncRNAs, and 2121 mRNAs obtained (fold change >2, false discovery rate <0.01). Based on the RNA interaction mechanism, a miRNA-lncRNA-mRNA network was constructed, through which a subnetwork composed of 5 miRNAs was discovered. hsa-miR-31-5p, hsa-miR-302a-3p, hsa-miR-302b-3p, hsa-miR-302d-3p, hsa-miR-3619-5p and the RNAs interaction with them have the potential to become novel targets to change the effect of existing immunotherapy. GO and KEGG analyses showed that these differentially expressed miRNAs, lncRNAs, and mRNAs may play key roles in tumorigenesis, tumor development, and drug efficacy, with natural killer cells potentially becoming the next emerging targets for immunotherapy enhancement. Moreover, survival analysis identified 10 lncRNAs as potential survival markers. CONCLUSIONS: This study identified novel immunotherapy targets and revealed potential biomarkers for COAD according to microsatellite status.

Listeria monocytogenes upregulates mitochondrial calcium signalling to inhibit LC3-associated phagocytosis as a survival strategy.

Mitochondria are believed to have originated ~2.5 billion years ago. As well as energy generation in cells, mitochondria have a role in defence against bacterial pathogens. Despite profound changes in mitochondrial morphology and functions following bacterial challenge, whether intracellular bacteria can hijack mitochondria to promote their survival remains elusive. We report that Listeria monocytogenes-an intracellular bacterial pathogen-suppresses LC3-associated phagocytosis (LAP) by modulation of mitochondrial Ca2+ (mtCa2+) signalling in order to survive inside cells. Invasion of macrophages by L. monocytogenes induced mtCa2+ uptake through the mtCa2+ uniporter (MCU), which in turn increased acetyl-coenzyme A (acetyl-CoA) production by pyruvate dehydrogenase. Acetylation of the LAP effector Rubicon with acetyl-CoA decreased LAP formation. Genetic ablation of MCU attenuated intracellular bacterial growth due to increased LAP formation. Our data show that modulation of mtCa2+ signalling can increase bacterial survival inside cells, and highlight the importance of mitochondrial metabolism in host-microbial interactions.

Outcomes of radiation therapy for resectable M0 gastric cancer.

BACKGROUND: The role of radiaotion therapy in resectable gastric cancer patients without distant metastases remains controversial. This retrospective analysis was performed to identify whether resectable gastric cancer patients without distant metastases might benefit from radiation. RESULTS: The results of the Kaplan-Meier analysis and log-rank test showed that a total of 3309 patients had a MST of 29.0 months, a 1-year survival rate of 74.7%, and a 3-year survival rate of 45.5%. Among them, the MST of the "RPS" group and the "RAS" group were significantly longer compared with that of the "No Radiation" group (32.7vs 32.9 vs 25.3 months, P < 0.05). The 1-year survival rates were 83.7%, 83.5% and 65.6% for the "RPS", "RAS" and "No radiation" groups, respectively (P < 0.05) and the 3-year survival rates were 52.6%, 63.6% and 44.9%, respectively (P < 0.05). The multivariate Cox proportional hazard regression analysis showed that radiation was an independent prognostic factor. MATERIALS AND METHODS: A total of 5744 patients from the SEER database who were initially diagnosed with histologically confirmed gastric cancer without distant metastases from 2010 to 2013 were included. Patients were divided into three groups as follows: patients who underwent radiation after surgery ("RAS" group), patients who underwent radiation prior to surgery ("RPS" group) and patients who did not undergo radiation ,only surgery performed ("No radiation'"group). CONCLUSIONS: This retrospective analysis demonstrated that "RPS" or "RAS"alone were independent prognostic factors for survival improvement in selected gastric cancer patients without distant metastases.

RLIP76 blockade by siRNA inhibits proliferation, enhances apoptosis, and suppresses invasion in HT29 colon cancer cells.

RLIP76, a multidomain protein which is a downstream effector of the small GTP ases RalA and RalB, is known to play a role in biological activities in a variety of malignant cancer cells. However, little study has been done on the role of RLIP76 in CRC. In this study, a RLIP76-targeted siRNA-containing vector was used to investigate the effect of RLIP76 knockdown on cellular functions in human CRC cell line HT29. Quantitative RT-PCR and Western blot analysis revealed that the expression levels of RLIP76 mRNA and protein in HT29 cells were significantly suppressed after transfection. Our results indicated that RLIP76 downregulation in HT29 CRC cells suppressed cell growth, enhanced cell apoptosis, induced cell cycle arrest, and inhibited cell invasion by decreasing MMP2 expression. Although the mechanisms through which RLIP76 regulates the cellular functions needs further investigation, our results indicate that RLIP76 may represent as a potential target of gene therapy for CRC treatment.

Icariin enhances radiosensitivity of colorectal cancer cells by suppressing NF-κB activity.

Radiation therapy is an integral part of the current therapeutic protocols in colorectal cancer. However, only a small proportion of the patients achieved complete pathological response because of the treatment-induced resistance to radiation. Previous studies have shown that radioresistance is associated with NF-κB activation and that suppression of NF-κB could potentiate the response of colorectal cancer cells to radiotherapy. Icariin, a natural flavonoid, has been shown to suppress NF-κB activity. The present study was carried out to investigate whether icariin could act as a radiosensitizer in colorectal cancer cells and murine model of the colorectal cancer. We also sought to understand the mechanisms underlying the icariin-mediated radiosensitization. Our results showed that icariin enhanced the radiation-mediated anti-proliferative effect both in vitro and in vivo. Further, icariin exerted the anti-proliferative and/or pro-apoptotic effect possibly, by: (1) inducing the cell arrest in G2/M phases of the cell cycle, or by (2) downregulating NF-κB and the anti-apoptotic gene products monitored by this transcription factor. Icariin could also potentiate the efficacy of radiotherapy in the murine model of colorectal cancer. Taken together, these results suggest that the use of icariin may provide with a new approach for sensitizing the radiotherapy in colorectal cancer.

Effect of BRMS1 on tumorigenicity and metastasis of human rectal cancer.

Breast cancer metastasis suppressor gene-1 (BRMS1) is newly discovered tumor metastasis gene, which has been reported to play an important role in the progression of human tumor. However, its role in rectal cancer has never been investigated. In this present study, we evaluated the associated of BRMS1 with colorectal cancer, its value in prognosis, and its role in metastasis of rectal cancer. BRMS1 expression examined in 80 patients and the role of BRMS1 in metastasis was studied using mice model. Our results showed that BRMS1 expression was significantly associated with clinicopathological parameters in rectal cancer patients and overexpression of BRMS1 in rectal cancer xenograft led to decreased growth, invasiveness and metastasis. Our findings indicate that high expression of BRSM1 in rectal cancer plays an essential role in tumor progression.