Receptor-interacting protein kinase 3 is a predictor of survival and plays a tumor suppressive role in colorectal cancer

5-Fluorouracil (5-FU) is a widely used drug for the therapy of cancer. However, the chemoresistance of tumor cells to 5-FU usually limits its clinical effectiveness. In this study, we explored the role of NLRP3 inflammasome in 5-FU resistance of oral squamous cell carcinoma (OSCC). The mRNA and protein expression levels of NLRP3, Caspase1 and IL-1β in resected OSCC specimens or cell lines were measured respectively by quantitative real time-PCR (qRT-PCR) and western blot. NLRP3 and Ki-67 expression in paraffin-embedded OSCC tissues was determined by immunohistochemistry. The correlation between 5-FU treatment and the expression and activation of NLRP3 inflammasome was further examined by evaluating NLRP3 and IL-1β expression in OSCC cell lines without or with NLRP3 knocked down. Cell viabilities of OSCC cells were determined by the MTT assay. Apoptosis and intracellular reactive oxygen species (ROS) of OSCC cells induced by 5-FU were measured by the flow cytometer. The carcinogen-induced tongue squamous carcinoma mice model was established by continuous oral administration of 4-nitroquinoline 1-oxide in wild-type BALB/c, Nlrp3 −/− and Caspase1 −/− mice. Tumor incidence were observed and tumor area were evaluated. In the clinical analysis, expression and activation of NLRP3 inflammasome was clearly increased in OSCC tissues of patients who received 5-FU-based chemotherapy. Multivariate Cox regression analysis revealed that this high expression was significantly correlated with tumor stage and differentiation, and was associated with poor prognosis. Moreover, 5-FU treatment increased expression and activation of NLRP3 inflammasome in OSCC cells in a cell culture system and xenograft mouse model. Silencing of NLRP3 expression significantly inhibited OSCC cell proliferation and enhanced 5-FU-induced apoptosis of OSCC cells. Further investigation showed that intracellular ROS induced by 5-FU promoted the expression and activation of NLRP3 inflammasome and increased the production of interleukin (IL)-1β, which then mediated the chemoresistance. With the carcinogen-induced OSCC model, we found less and later tumor incidence in Nlrp3 −/− and Caspase1 −/− mice than wild-type mice. And greater decrease of tumor area was observed in the gene deficient mice treated with 5-FU. Our findings suggest that NLRP3 inflammasome promoted 5-FU resistance of OSCC both in vitro and in vivo, and targeting the ROS/NLRP3 inflammasome/IL-1β signaling pathway may help 5-FU-based adjuvant chemotherapy of OSCC.

Inflammasomes are reported to be abnormally expressed and activated in several malignancies and play important roles in tumor development. The present study was designed to investigate the expression and function of the NLR family pyrin domain containing protein 3 (NLRP3) inflammasome in oral squamous cell carcinoma (OSCC). NLRP3 expression in OSCC cell lines and the normal human immortalized oral epithelial cells (HIOEC) was determined by real-time PCR and western blot. Immunohistochemistry was used to examine the expression of NLRP3 and IL-1β in the paraffin-embedded OSCC tissues. The proliferation of OSCC cells was detected by the 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and cell colony formation ability of the OSCC cells was also evaluated. Tumor cell migration or invasion was measured by the transwell assay and related protein markers were determined by western blot. A mouse xenograft model was established to investigate the OSCC tumor growth in vivo. Significant higher expression of NLRP3 was observed in the OSCC cells. Obvious expression of NLRP3 and IL-1β was found in the paraffin-embedded OSCC tissues, and the NLRP3 expression levels were correlated with the tumor size, lymphonode metastatic status and IL-1β expression. Downregulating NLRP3 expression markedly reduced the cleavage of caspase-1 and production of IL-1β in OSCC cells. NLRP3 knockdown also inhibited the proliferation, migration and invasion of OSCC cells. Further investigation indicated that expressions of E-cadherin and vimentin in OSCC cells were increased, while N-cadherin expression was decreased after NLRP3 knockdown. Downregulating NLRP3 expression in OSCC cells significantly reduced the tumor growth in vivo. Our data suggested that the increased expression of NLRP3 in OSCC was associated with tumor growth and metastasis. NLRP3 may be considered as a potential target for OSCC therapy.

Circulating exosomal microRNAs (ExmiRNAs) provide an ideal non-invasive method for cancer diagnosis. In this study, we evaluated two circulating ExmiRNAs in NSCLC patients as a diagnostic tool for early-stage non-small lung cancer (NSCLC). The exosomes were characterized by qNano, transmission electron microscopy, and Western blot, and the ExmiRNA expression was measured by microarrays. The differentially expressed miRNAs were verified by RT-qPCR using peripheral blood specimens from NSCLC patients ( n = 276, 0 and I stage: n = 104) and healthy donors ( n = 282). The diagnostic values were measured by receiver operating characteristic (ROC) analysis. The results show that the expression of both ExmiR-20b-5p and ExmiR-3187-5p was drastically reduced in NSCLC patients. The area under the ROC curve (AUC) was determined to be 0.818 and 0.690 for ExmiR-20b-5p and ExmiR-3187-5p, respectively. When these two ExmiRNAs were combined, the AUC increased to 0.848. When the ExmiRNAs were administered with either carcinoembryonic antigen (CEA) or cytokeratin-19-fragment (CYFRA21-1), the AUC was further improved to 0.905 and 0.894, respectively. Additionally, both ExmiR-20b-5p and ExmiR-3187-5p could be used to distinguish early stages NSCLC (0 and I stage) from the healthy controls. The ROC curves showed that the AUCs were 0.810 and 0.673, respectively. Combination of ExmiR-20b-5p and ExmiR-3187-5p enhanced the AUC to 0.838. When CEA and CYFRA21-1 were administered with the ExmiRNAs, the AUCs were improved to 0.930 and 0.928, respectively. In summary, circulating serum exosomal miR-20b-5p and miR-3187-5p could be used as effective, non-invasive biomarkers for the diagnosis of early-stage NSCLC, and the effects were further improved when the ExmiRNAs were combined.Impact statement: The high mortality of non-small cell lung cancer (NSCLC) is mainly because the cancer has progressed to a more advanced stage before diagnosis. If NSCLC can be diagnosed at early stages, especially stage 0 or I, the overall survival rate will be largely improved by definitive treatment such as lobectomy. We herein validated two novel circulating serum ExmiRs as diagnostic biomarkers for early-stage NSCLC to fulfill the unmet medical need. Considering the number of specimens in this study, circulating serum exosomal miR-20b-5p and miR-3187-5p are putative NSCLC biomarkers, which need to be further investigated in a larger randomized controlled clinical trial.

Interleukin-18 (IL-18) belongs to the IL-1 family and is an essential proinflammatory and immune regulatory cytokine. The present study was designed to investigate the expression and function of IL-18 in colon cancer. In clinical analyses, mRNA and protein expressions of IL-18 were decreased in tissues of colon cancer patients. This decreased expression of IL-18 was significantly correlated with the tumor size ( ) and American Joint Committee on Cancer (AJCC) stage ( ). Patients with IL-18-positive tumors had a better survival rate than patients with IL-18-negative tumors. Moreover, upregulation of IL-18 inhibited colon cancer cell proliferation. Our data suggest that the decreased expression of IL-18 in colon cancer was associated with prognosis and tumor proliferation. IL-18 may be considered a novel tumor suppressor and a potential therapeutic target for colon cancer patients.

Structural Maintenance of Chromosomes 4 is a Predictor of Survival and a Novel Therapeutic Target in Colorectal Cancer Structural maintenance of chromosomes 4;colorectal cancer;potential therapeutic target; Background: Structural maintenance of chromosomes 4 (SMC-4) is a chromosomal ATPase which plays an important role in regulate chromosome assembly and segregation. However, the role of SMC-4 in the incidence of malignancies, especially colorectal cancer is still poorly understood. Materials and Methods: We here used quantitative PCR and Western blot analysis to examine SMC-4 mRNA and protein levels in primary colorectal cancer and paired normal colonic mucosa. SMC-4 clinicopathological significance was assessed by immunohistochemical staining in a tissue microarray (TMA) in which 118 cases of primary colorectal cancer were paired with noncancerous tissue. The biological function of SMC-4 knockdown was measured by CCK8 and plate colony formation assays. Fluorescence detection has been used to detect cell cycling and apoptosis. Results: SMC-4 expression was significantly higher in colorectal cancer and associated with T stage, N stage, AJCC stage and differentiation. Knockdown of SMC-4 expression significantly suppressed the proliferation of cancer cells and degraded its malignant degree. Conclusions: Our clinical and experimental data suggest that SMC-4 may contribute to the progression of colorectal carcinogenesis. Our study provides a new therapeutic target for colorectal cancer treatment.