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Colorectal cancer (CRC) is the third most common cancer in the world. The accessibility of the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus data allows the prognostic evaluation of CRC. Fibroblasts play a key role in the development and progression of tumors while fibroblast-related risk signature in CRC patients has rarely been mentioned. In this study, TCGA data was classified into high-fibroblast and low-fibroblast groups according to the median of fibroblast content. Among 3845 differentially expressed genes between two groups, 14 prognostic genes commonly expressed in GSE39582 and TCGA were identified by LASSO-COX analysis. Then we established a fibroblast-related risk signature in TCGA training group and validated in the GSE39582 testing group. The risk score was significantly associated with the overall survival (OS), and the poor prognosis of patients in high-risk group might relate to the immune cell infiltration in the tumor microenvironment, epithelial-mesenchymal transition, and extracellular matrix related processes. Overall, we proved that the fibroblast-related signature could predict the prognosis of patients which might shed light on the treatment of CRC.

Increased xCT and transsulfuration pathway has been associated with metabolic reprogramming of colorectal cancer. However, the correlation between these 2 events and the underlying molecular mechanism remains obscure. xCT expression was determined in tissue microarrays of colorectal cancer. RNA sequencing and functional assays in vitro was adopted to delineate the involvement of transsulfuration pathway in the proper function of xCT in maintaining the chemoresistant phenotype. The synthetic lethality of blocking xCT and the transsulfuration pathway was investigated both in vitro and in vivo. The up-regulation of the transsulfuration pathway after inhibiting xCT in colon cancer cells was evident and exogenous H2S partially reversed the loss of chemoresistance phenotype after inhibiting xCT. Mechanistically, CTH derived H2S increased the stability of xCT through persulfidation of OTU domain-containing ubiquitin aldehyde-binding protein 1 at cysteine 91. AOAA and Erastin resulted in synthetic lethality both in vitro and in vivo, which was mediated through increased ferroptosis and apoptosis. Our findings suggest that a reciprocal regulation exists between xCT and the transsulfuration pathway, which is a targetable metabolic vulnerability. Mechanistically, CTH derived H2S increased the stability of xCT through persulfidation of OTU domain-containing ubiquitin aldehyde-binding protein 1 at cysteine 91.

Background: As the third confirmed gaseous transmitter, the role of hydrogen sulfide (H2S) in the pathogenesis of multiple types of cancer has been attracting increasing attention. Increased expression of cystathionine β-synthase (CBS) and H2S in colon cancer tissue samples has been validated and tumor-derived H2S, mainly produced by CBS, stimulates bioenergetics, cell proliferation, and angiogenesis in colon cancer. Recently, the therapeutic manipulation of H2S has been proposed as a promising anticancer approach. However, the effect of aminooxyacetic acid (AOAA), which has been widely used as an inhibitor of CBS dependent synthesis of H2S, on the chemotherapeutic effect of oxaliplatin (OXA) and the underlying mechanisms remain to be illustrated. Methods: We examined the expression of CBS in human colorectal cancer specimens and matched normal mucosa by immunohistochemistry. The effect of AOAA on the sensitivity of colon cancer cells to OXA and the level of apoptosis induced by caspase cascade was investigated in both HCT116 and HT29 cell lines utilizing CCK-8 assays, flow cytometry analysis and western blot analysis. The endogenous levels of reactive oxygen species (ROS) were detected fluorescently by DCF-DA, and glutathione (GSH) levels were measured by a Total GSH Detection Kit. Tumor bearing xenograft mouse models and in vivo imaging systems were further used to investigate the effect of AOAA in vivo and immunohistochemistry (IHC) and TUNEL analysis were performed. Results: In the current study, we confirmed CBS, the main target of AOAA, is overexpressed in human colorectal cancer by immunohistochemistry. The inhibitory effect of AOAA on the synthesis of H2S was validated utilizing fluorescent probe and specific electrode. AOAA significantly reduced the IC50 values of OXA in both colon cancer cell lines. Co-incubation with AOAA elicited increased apoptosis induced by OXA, featured by increased activation of caspase cascade. Besides, AOAA further increased the levels of ROS induced by OXA and attenuated the synthesis of glutathione (GSH), which is a vital antioxidant. Besides, the results of in vivo imaging and following IHC and TUNEL analysis were in accordance with cellular experiments, indicating that AOAA sensitizes colon cancer cells to OXA via exaggerating intrinsic apoptosis. Conclusion: The results suggested that CBS is overexpressed in colorectal cancer tissues and AOAA sensitizes colon cancer cells to OXA via exaggerating apoptosis both in vitro and in vivo. Decreasing the endogenous level of GSH and consequently impaired detoxification of ROS might be one of the mechanisms underlying the effect of AOAA.

We previously identified a novel lncRNA, CRART16, that could induce cetuximab resistance in colorectal cancer cells. This study explored the relationship of CRART16 expression to gastric cancer progression and the molecular mechanisms involved.We evaluated CRART16 expression in gastric cancer tissues and adjacent normal tissues from the TCGA database and our hospital. Besides, we assessed its relationship with the overall survival (OS) of patients with gastric cancer. The effects of CRART16 on gastric cancer angiogenesis were determined by endothelial tube formation assay, spheroid sprouting assay, HUVEC invasion assay, and chick embryo chorioallantoic membrane (CAM) assay. The involvement of the lncRNA CRART16/miR-122-5p/FOS axis was analyzed by western blotting and dual-luciferase reporter assay. The functions of CRART16 were confirmed in xenograft mouse models.We found that CRART16 was substantially overexpressed in gastric cancer tissues compared with normal tissues, based on the TCGA database and our clinical samples. High expression of CRART16 correlated with more advanced tumor stages and poor prognosis. Overexpression of CRART16 in gastric cancer cells promoted proliferation, colony formation, angiogenesis, and bevacizumab resistanceOur findings demonstrate that CRART16 promotes angiogenesis

Methylation of circulating free DNA (CfDNA) has emerged as an efficient marker of tumor screening and prognostics. However, no efficient methylation marker has been developed for monitoring liver metastasis (LM) in colorectal cancer (CRC). Utilizing methylome profiling and bisulfite sequencing polymerase chain reaction of paired primary and LM sites, significantly increased methylation of TCHH was identified in the process of LM in CRC in the present study. Methylight analysis of TCHH methylation in CfDNA displayed a promisingly discriminative power between CRC with and without LM. Besides, significant coefficient of TCHH methylation and LM tumor volume was also validated. Together, these results indicated the potential of TCHH methylation in CfDNA as a monitoring marker of LM in CRC.

This study investigated the protective effect of Escherichia coli Nissle 1917 (EcN) on intestinal barrier and the mechanism in the context of acute severe inflammation.In this study, mice received lipopolysaccharide (LPS) intraperitoneal injection with or without EcN administration to construct a mouse model of endotoxemia. Clinical scores, intestinal permeability, inflammatory cytokines and histopathological analysis of four main organs from different groups were assessed. The expression of tight junction proteins and activation of RhoA/ROCK2/MLC signaling were examined using western blotting. The localization of tight junction proteins was examined by immunofluorescence. Caco-2 monolayers with or without TLR-4 knockdown were incubated with EcN or TNF-α/IFN-γ and the monolayer barrier function was assessed by transepithelial electrical resistance (TER) and FITC-dextran 4000 Da (FD-4) flux. The expression of tight junction proteins and activation of RhoA/ROCK2/MLC signaling were examined by western blotting. The localization of tight junction proteins was examined by immunofluorescence.We found that EcN downregulated the RhoA/ROCK2/MLC signaling pathway to preserve barrier function and alleviated systemic inflammation in mouse model. And EcN also protected barrier function of Caco-2 monolayers by inhibiting the activation of RhoA/ROCK2/MLC signaling via TLR-4.The results indicated that EcN protected the intestinal barrier function in endotoxemia through inhibiting the activation of RhoA/ROCK2/MLC signaling via TLR-4.

The long noncoding (lnc) RNA H19 was involved in the tumorigenesis of many types of cancer. However, the role of H19 in the tumorigenesis of colon cancer has not been fully illustrated. Recent studies suggested a potential relationship between H19 and vitamin D receptor (VDR) signaling. Considering the pivotal role of VDR signaling in the colon epithelium both physiologically and pathologically, the correlation between H19 and VDR signaling may have an important role in the development of colon cancer. In this study, the correlation between H19 and vitamin D receptor (VDR) signaling and the underlying mechanisms in colon cancer were investigated both in vitro and in vivo. The results suggested that VDR signaling was able to inhibit the expression of H19 through regulating C-Myc/Mad-1 network. H19, on the other hand, was able to inhibit the expression of VDR through micro RNA 675-5p (miR-675-5p). Furthermore, H19 overexpression induced resistance to the treatment with 1,25(OH)2D3 both in vitro and in vivo. Together, these results suggested that H19 overexpression might be one of the mechanisms underlying the development of resistance to the treatment with 1,25(OH)2D3 in the advanced stage of colon cancer.

Colorectal cancer (CRC) is one of the most deadly gastrointestinal malignancies. The openness of the Cancer Genome Atlas (TCGA) allows us to perform correlation analysis between large-scale transcriptome data and overall survival (OS) of multiple malignancies. Previous literature reports that the infiltration of immune cells and stromal cells in the tumor microenvironment (TME) significantly associate with the prognosis of cancers. Based on the ESTIMATE algorithm, the immune and stromal components in TME can be quantified by immune and stromal scores. To determine the effects of immune and stromal cell associated genes on CRC prognosis, we divided the CRC cases into high- and low-groups based on the immune/stromal scores and identified 999 differentially expressed genes (DEGs). Heatmaps, functional enrichment analysis and protein‐protein interaction (PPIs) networks further indicated that 999 DEGs mainly participated in stromal composition and immune response. Finally, we obtained 56 genes that were significantly associated with CRC prognosis from 999 DEGs and identified the PPIs networks. The role of 41 genes in CRC has been reported in previous literature, and the other 15 genes have never been reported. Therefore, we found 15 novel TME genes associated with CRC prognosis waiting for more researches.

Acquired resistance to 5-fluorouracil (5-FU) is a major barrier to benefit from chemotherapy in colon cancer patients. Hydrogen sulfide (H2S), mainly produced by cystathionine-β-synthase (CBS), has been reported to promote the proliferation and migration of colon cancer cells. In this study, the effect of inhibiting H2S synthesis on the sensitivity of colon cancer cell lines to 5-FU was investigated. Increased expression of CBS was validated in online database and tissue microarrays. Inhibiting H2S synthesis significantly sensitized colon cancer cell lines to 5-FU both in vitro and in vivo. Decreasing H2S synthesis utilizing shRNA lentiviruses significantly reversed the acquired resistance to 5-FU. MicroRNA sequencing was performed and miR-215-5p was revealed as one of the miRNAs with most significantly altered expression levels after CBS knock down. Epiregulin (EREG) and thymidylate synthetase (TYMS) were predicted to be potential targets of miR-215-5p. Decreasing H2S synthesis significantly decreased the expression of EREG and TYMS. These results demonstrate that inhibiting H2S synthesis can reverse the acquired resistance to 5-FU in colon cancer cells.

Aims The present study investigated the effect of Escherichia coli Nissle 1917 (EcN) on irinotecan-induced intestinal barrier dysfunction and gut microbial dysbiosis in a mouse model and in the human colonic cells lines Caco-2. Materials and methods Male BALB/c mice received irinotecan intraperitoneal injection with or without EcN administration intragastrically. Body weight, diarrhea severity, intestinal permeability and histopathological analysis of ileum epithelia of mice from different groups were assessed. The expression and localization of tight junction proteins were examined using western blot and immunofluorescence. Gut microbiota structure and diversity were measured with 16 S rRNA sequencing. Caco-2 monolayers were incubated with EcN culture supernatant (EcNsup) or SN-38 and the monolayer barrier function was assessed by transepithelial electrical resistance (TER) and FITC-dextran 4000 Da (FD-4) flux. Key findings Pretreatment with EcN significantly attenuated irinotecan-induced weight loss and diarrhea in mice. In addition, EcN inhibited the increased intestinal permeability and decreased Claudin-1 expression in irinotecan-treated mice. Furthermore, irinotecan treatment decreased the diversity of gut microbiota and increased the relative abundance of Proteobacteria compared to control group. EcN administration ameliorated the gut microbiota dysbiosis. In Caco-2 monolayers, EcNsup ameliorated the decreased TER and increased FD-4 flux elicited by SN-38. Moreover, EcNsup attenuated SN-38-induced altered localization and distribution of Claudin-1 in Caco-2 monolayers. Significance Our results indicated that the administration of EcN protected against irinotecan-induced intestinal injury by regulating intestinal barrier function and gut microbiota.

Background and Aims Endogenous H2S regulates multiple physiological and pathological processes in colon epithelial tissues. The current study investigated the role of cystathionine β-synthase [CBS], a major producer of H2S in colon epithelial cells, in the pathogenesis of ulcerative colitis [UC]-related intestinal barrier injury. The expression and DNA methylation level of CBS were investigated in inflamed and non-inflamed colon tissues collected from UC patients, and the effect of decreased CBS levels on Caco-2 monolayer barrier injury and altered status of tight junctions elicited by tumour necrosis factor/interferon [TNF/IFN] was determined. Methods The expression of CBS and the methylation level of the CBS promoter were assessed in non-inflamed and inflamed colon epithelial tissue samples collected from UC patients. Barrier function, status of tight junction proteins and activation of the NF-κB p65-mediated MLCK-P-MLC signalling pathway were further investigated in Caco-2 monolayers. Results Decreased expression of CBS and elevated methylation levels of the CBS promoter were observed in inflamed sites compared with in non-inflamed sites in the colon epithelial samples from UC patients. In Caco-2 monolayers, decreased expression of CBS exacerbated TNF/IFN-induced barrier injury and altered localization of tight junction proteins. Decreased expression of CBS predisposed Caco-2 monolayers to injury elicited by TNF/IFN via augmentation of the NF-κB p65-mediated MLCK-P-MLC signalling pathway. Conclusions Decreased expression of CBS propagates the pathogenesis of UC by exacerbating inflammation-induced intestinal barrier injury. Elevated methylation of the CBS promoter might be one of the mechanisms underlying the decreased expression of CBS in inflamed sites of colon epithelial tissues from UC patients.

Escherichia coli Nissle 1917 (EcN), a kind of probiotic, has been reported to have a protective effect on the intestinal barrier function and can ameliorate certain gastrointestinal disorders. In this study, the potential protective effect of EcN on the intestinal barrier function in a septic mouse model induced by cecal ligation and puncture (CLP) operation was investigated. FITC-Dextran 4,000 Da (FD-4) flux and the expression levels of tight junction (TJ) proteins were measured to evaluate the protective effect of EcN on the intestinal barrier function. Then, Caco-2 monolayers were utilized to further investigate the protective effect of the EcN supernatant (EcNsup) on the barrier dysfunction induced by TNF-α and IFN-γ in vitro; the plasma level of both the cytokines increased significantly during sepsis. Transepithelial electrical resistance (TEER) and FD-4 transmembrane flux were measured, and the localization of ZO-1 and Occludin was investigated by immunofluorescence. The expression of MLCK and the phosphorylation of MLC were detected by western blot. The activation of NF-κB was explored by immunofluorescence, and CHIP assays were performed to investigate the conjunction of NF-κB with the promoter of MLCK. The results indicated that EcN protected the intestinal barrier function in sepsis by ameliorating the altered expression and localization of TJ proteins and inhibiting the NF-κB-mediated activation of the MLCK-P-MLC signaling pathway which might be one of the mechanisms underlying the effect of EcN.

Intestinal barrier injury has been reported to play a vital role in the pathogenesis of endotoxemia. This study aimed to investigate the protective effect of GYY4137, a newly synthesized H2S donor, on the intestinal barrier function in the context of endotoxemia both in vitro and in vivo. Caco-2 (a widely used human colon cancer cell line in the study of intestinal epithelial barrier function) monolayers incubated with lipopolysaccharide (LPS) or TNF-α/IFN-γ and a mouse model of endotoxemia were used in this study. The results suggested that GYY4137 significantly attenuated LPS or TNF-α/IFN-γ induced increased Caco-2 monolayer permeability. The decreased expression of TJ (tight junction) proteins induced by LPS and the altered localization of TJs induced by TNF-α/IFN-γ was significantly inhibited by GYY4137; similar results were obtained in vivo. Besides, GYY4137 promoted the clinical score and histological score of mice with endotoxemia. Increased level of TNF-α/IFN-γ in the plasma and increased apoptosis in colon epithelial cells was also attenuated by GYY4137 in mice with endotoxemia. This study indicates that GYY4137 preserves the intestinal barrier function in the context of endotoxemia via multipathways and throws light on the development of potential therapeutic approaches for endotoxemia.

Primary liver cancer (PLC) is a fatal disease that affects millions of lives worldwide. PLC is the leading cause of cancer-related deaths and the incidence rate is predicted to rise in the coming decades. PLC can be categorized into three major histological subtypes: hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC), and combined HCC-ICC. These subtypes are distinct with respect to epidemiology, clinicopathological features, genetic alterations, and clinical managements, which are thoroughly summarized in this review. The state of treatment strategies for each subtype, including the currently approved drugs and the potential novel therapies, are also discussed., Graphical Abstract, Public Summary • Primary liver cancer comprises HCC, ICC, cHCC-ICC, which are markedly distinct in their epidemiology, clinical features and response to therapy • HCC is viral infection-related malignancy with specific histological features, whereas ICC is associated with chronic liver inflammation • HCC is prone to respond to targeted therapy, immunotherapy, and antiviral agents, whereas ICCs are benefit from chemotherapy, targeted therapy, and immunotherapy • Combined cHCC-ICC subclass shows strong ICC-like features and is considered to be treated like ICC, whereas mixed cHCC-ICC subclass resembles HCC and is treated like HCC

To investigate the clinicopathological features and prognosis of colorectal synchronous multiple primary cancer(SMPC).From January 2008 to June 2011, 51 patients diagnosed with colorectal SMPC underwent surgery at Department of General Surgery of Peking University First Hospital. Their clinicopathological features, diagnosis, treatment and prognosis were summarized and analyzed. SMPC was diagnosed according to the following criteria: each tumor must have a definite pathologic picture of malignancy; metastasis or recurrence from another colorectal cancer was excluded; tumors must be distinctly separated by at least 5 cm of all intact bowel wall from each other; SMPC has abnormal cells between tumor and normal mucosa and abnormal gland of transitional zone; each cancer is infiltrating carcinoma except the carcinoma in situ; all the cancers are detected at the same time or within 6 months. Multiple primary colorectal cancer originated from familial colonic polyposis or ulcerative colitis was excluded.These 51 colorectal SMPC patients accounted for 3.5% of 1 452 colorectal cancer patients in the same period at our hospital, with 32 males and 19 females, and mean age of (63±13)(29 to 82) years. Of 51 cases, 46(90.2%) had 2 original carcinoma, 3(5.9%) had 3 original carcinoma and 2(3.9%) had 4 carcinoma; 23(45.1%) complicated with colon polyps, 4(7.8%) complicated with malignancy outside the colorectum. In TNM staging, 7(13.7%), 15(29.4%), 24(47.1%) and 5(9.8%) patients were stage I(, II(, III( and IIII( respectively. Among 51 patients undergoing surgery by different procedures, 16 were subtotal colon resection, 8 were extended right colon resection, 5 were extended left hemicolon resection, 8 were right hemicolon resection plus Dixon procedure, 10 were Dixon, and 4 were right hemicolon resection plus sigmoid colon resection. Adjuvant chemotherapy and support treatment were given according to the condition after operation. A total of 105 tumors were found, including 25(23.8%) tumors in sigmoid colon, 24(22.9%) in rectum, 22(21.0%) in ascending colon and 4 in organs outside the colorectum. Tubular adenocarcinoma (86/105, 81.9%) was the main pathological type in these colorectal SMPC patients. During the follow-up of median 43.5 months, 10 cases presented local recurrence and 6 cases had liver metastasis. Multivariable analysis showed that ≤65 years old (OR=22.757, 95%CI: 1.562-331.543, P=0.002),undifferentiated carcinoma or mucous adenocarcinoma (OR=27.174, 95%CI: 2.834-260.512, P=0.004), stage III(-IIII( (OR=29.626, 95%CI: 3.216-272.884, P=0.003) were independent risk factors of postoperative 5-year recurrence and metastasis, but the number of SMPC lesions and the surgical method were not associated with postoperative 5-year recurrence and metastasis (P=0.564, P=0.513). The 3-year and 5-year survival rates of colorectal SMPC patients were 76.5% and 64.7%.Two-original carcinoma is the most common in colorectal SMPC patients, which mainly distributes in sigmoid colon and rectum. Postoperative monitoring should be strengthened for those patients with younger age, poor pathological types and advanced staging to prevent recurrence and metastasis.

AIM This study aimed to analyse the potential significance of metastasis to the inferior mesenteric artery lymph node (IMA-LN) in patients with malignancy of the left colon and rectum. METHOD A retrospective analysis of a cohort of 890 patients collected prospectively who underwent radical resection of a primary tumour of the descending colon, sigmoid colon and rectum in our department from 1 January 2009 to 31 December 2015 was performed. Patients were divided into an IMA-LN metastasis (IMA-LN (+)) group (n = 51) and a non IMA-LN metastasis (IMA-LN (-)) group (n = 839). A total of 801 patients were followed by a designated member of the study staff. Clinical features, pathological characteristics, recurrence patterns and survival rates were compared between the two groups. RESULTS In the IMA-LN (+) group, the risk ratio of overall recurrence and tumour related death was 7.786 (95% CI 4.142-14.637) and 7.756 (95% CI 4.142-14.525) respectively. Significant differences were found in overall survival (log-rank: χ2 = 69.06, P

BACKGROUND Recently, long noncoding RNA (lncRNA) H19 has been reported to be related with VDR signaling and the development of inflammatory diseases including osteoarthritis. The aim of this study was to investigate the correlation between the expression level of H19 and VDR in ulcerative colitis (UC) tissues and to investigate the effect of H19 overexpression on intestinal epithelial barrier function. METHODS The expression level of H19, miR-675-5p, and VDR in UC tissues and paired normal tissues collected from 12 patients with UC was investigated by quantitative real-time polymerase chain reaction. Caco-2 monolayers were used to test the effect of H19 and miR-675-5p overexpression on the intestinal epithelial barrier function and the status of tight junction proteins and VDR. Luciferase assay was used to validate the target site of miR-675-5p in the 3'UTR of VDR mRNA. RESULTS The expression of H19 was found to be negatively correlated with the expression of VDR in UC tissues (r = 0.5369, P < 0.05). The expression of miR-675-5p was also found to be negatively correlated with the expression of VDR in UC tissues (r = 0.5233, P < 0.01). H19 overexpression increased Caco-2 monolayer permeability and decreased the expression of tight junction proteins and VDR, which was significantly attenuated by cotransfection with miR-675-5p inhibitors. The 3'UTR of VDR mRNA was validated to be one of the direct targets of miR-675-5p. CONCLUSIONS This study reveals the destructive effect of H19 overexpression on intestinal epithelial barrier function and suggests a potential role of H19 in the development of UC. In addition, H19 overexpression may be one of the mechanisms underlying the decreased expression of VDR in UC tissues and the interaction between H19 and VDR signaling may provide potential therapeutic targets for UC.

The human cervical cancer oncogene (HCCR) has been found to be overexpressed in a variety of human cancers. However, the level of expression of HCCR and its biological function in gastric cancer are largely unknown. In this study, we evaluated HCCR expression in several gastric cancer cell lines and in one normal gastric mucosal cell line. We established a 5-FU-resistant gastric cancer cell subline, and we evaluated its HCCR expression. HCCR expression levels were high in gastric cancer lines, and expression was significantly increased in the 5-FU-resistant cancer cell subline. HCCR expression affected cell growth by regulating apoptosis in the cancer cells, and it had a positive correlation with p-STAT3 expression. Western blot and luciferase reporter assays showed that the activation of STAT3 upregulated HCCR expression in a positive feedback loop model. In vivo and in vitro studies showed that HCCR plays an important role in the apoptosis induced by 5-FU. Our data demonstrate that HCCR is probably involved in apoptosis and cancer growth and that it functions as a p-STAT3 stimulator in a positive feedback loop model. In gastric cancer cells, HCCR confers a more aggressive phenotype and resistance to 5-FU-based chemotherapy.

Increased expression of cystathionine-β-synthase (CBS) has been validated in multiple kinds of tumor tissues, including colorectal cancer. Endogenous hydrogen sulfide (H2S), produced by CBS, was able to promote the proliferation and migration of colon cancer cells by inhibiting apoptosis and injuries caused by noxious environmental factors, including chemotherapeutic agents. Recently, overexpression of CBS has been reported to play a pivotal role in tumorigenesis of colon cancer cells, rendering the normal colon epithelial cell line acquiring the features of malignant cells. However, the potential role of CBS in the development of chemoresistance of colon cancer cells has not be illustrated. In the present study, overexpression of CBS in tumor tissues was further validated by realtime PCR and the effect of inhibition of both the activity and expression of CBS on the sensitivity to 5-fluorouracil (5-FU) was investigated in colon cancer cell lines. Inhibition of the activity of CBS by CBS inhibitor aminooxyacetate (AOAA) significantly increased the sensitivity of colon cancer cell lines to 5-FU, featured by decreased IC50 and colony forming efficiency. However, utilizing a slowly releasing H2S donor GYY4137, the present study suggested that exogenous hydrogen sulfide was able to increase the resistance to 5-FU in both colon cancer cell lines. What's intriguing was that, 5-FU, at clinically relevant concentrations, significantly inhibited the expression of CBS. Co-treatment of AOAA significantly increased the expression of Bax and decreased the expression of Bcl-2, indicating the involvement of increased apoptosis. AOAA also predisposed the colon cancer cells to the inhibition of cellular energetics induced by 5-FU, featured by the further reduced level of cellular ATP. These results suggested that inhibition of CBS promoted the sensitivity of colon cancer cells to 5-FU via increasing apoptosis and inhibiting cellular bioenergetics. Furthermore, inhibition of CBS expression by shRNA sensitizes the 5-FU resistant colon cancer cell line HCT-8/5-FU to treatment with 5-FU. The increased expression of CBS and the consequently increased level of endogenous H2S might be a potential therapeutic target for chemoresistance in colon cancer. Citation Format: Shanwen Chen, Pengyuan Wang, Yisheng Pan, Yucun Liu. Inhibition of cystathionine-β-synthase (CBS) sensitizes colon cancer cells to 5-FU via increasing apoptosis and inhibiting cellular bioenergetics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5840.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been reported to inhibit proliferation and migration of multiple types of cancer cells. However, the mechanism underlying its anti-metastasis effect is not fully illustrated. In this study, the effect of 1,25(OH)2D3 on TGF-β1/β2-induced epithelial-mesenchymal transition (EMT) is tested in colon cancer cells. The results suggest that 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased invasion and migration of in SW-480 and HT-29 cells. 1,25(OH)2D3 also inhibited the cadherin switch in SW-480 and HT-29 cells. TGF-β1/β2-induced increased expression of EMT-related transcription factors was also inhibited by 1,25(OH)2D3. 1,25(OH)2D3 also inhibited the secretion of MMP-2 and MMP-9 and increased expression of F-actin induced by TGF-β1/β2 in SW-480 cells. Taken together, this study suggests that the suppression of EMT might be one of the mechanisms underlying the anti-metastasis effect of 1,25(OH)2D3 in colon cancer cells.

Studies have verified the protective effect of Hydrogen Sulfide (H2S) on gastric ulcer and ulcerative colitis, but the mechanisms are not fully illustrated. In this study, the possible protective effect of H2S on TNF-α/IFN-γ induced barrier dysfunction was investigated in Caco-2 cell monolayers. The barrier function of Caco-2 monolayers was evaluated by measuring trans-epithelial electrical resistance (TEER) and FITC-Dextran 4 kDa (FD-4) trans-membrane flux. ZO-1 and Occludin were chosen as markers of the localization of tight junction (TJ) proteins for immunofluorescence. The expression of MLCK and phosphorylation level of myosin light chain (MLC) were measured by immunoblotting. The activation of NF-kB p65 was analyzed by EMSA and immunofluorescence. NaHS at 500uM significantly attenuated TNF-α/IFN-γ-indueced Caco-2 monolayer barrier injury. The increased expression of MLCK and increased phosphorylation level of MLC induced by TNF-α/IFN-γ was also inhibited significantly by NaHS. Additionally, NaHS inhibited TNF-α/IFN-γ induced activation and nuclear translocation of NF-kB p65. The present study reveals the protective effect of H2S on TNF-α and IFN-γ-induced injury of intestinal epithelial barrier function in Caco-2 monolayers and suggests that the suppression of MLCK-P-MLC signaling mediated by NF-kB P65 might be one of the mechanisms underlying the protective effect of H2S.

Studies have suggested the role of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in protecting intestinal barrier function from injuries induced by multiple reagents. Vitamin D deficiency was reported to be associated with poor prognosis in patients with alcoholic liver disease (ALD). This study is designed to investigate the effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier dysfunction and the underlying mechanisms utilizing Caco-2 cell monolayers and a mouse model with acute ethanol injury. In Caco-2 monolayers, ethanol significantly increased monolayer permeability, disrupted TJ distribution, increased phosphorylation level of MLC, and induced generation of ROS compared with controls. However, pre-treatment with 1,25(OH)2D3 greatly ameliorated the ethanol-induced barrier dysfunction, TJ disruption, phosphorylation level of MLC, and generation of ROS compared with ethanol-exposed monolayers. Mice fed with vitamin d-sufficient diet had a higher plasma level of 25(OH)D3 and were more resistant to ethanol-induced acute intestinal barrier injury compared with the vitamin d-deficient group. These results suggest that the suppression of generation of ROS and increased phosphorylation level of MLC might be one of the mechanisms underlying the protective effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier injury and provide evidence for the application of vitamin D as therapeutic factors against ethanol-induced gut leakiness.