Mendelian randomization study of causal link from gut microbiota to colorectal cancer.

Recent studies have shown the relevance of gut microbiota in the occurrence and development of colorectal cancer (CRC), but the causal relationship remains unclear in the human population. The present study aims to assess the causal relationship from the gut microbiota to CRC and to identify specific causal microbe taxa via genome-wide association study (GWAS) summary statistics based two-sample Mendelian randomization (MR) analyses. Microbiome GWAS (MGWAS) in the TwinsUK 1,126 twin pairs was used as discovery exposure sample, and MGWAS in 1,812 northern German participants was used as replication exposure sample. GWAS of CRC in 387,156 participants from the UK Biobank (UKB) was used as the outcome sample. Bacteria were grouped into taxa features at both family and genus levels. In the discovery sample, a total of 30 bacteria features including 15 families and 15 genera were analyzed. Five features, including 2 families (Verrucomicrobiaceae and Enterobacteriaceae) and 3 genera (Akkermansia, Blautia, and Ruminococcus), were nominally significant. In the replication sample, the genus Blautia (discovery beta=-0.01, P = 0.04) was successfully replicated (replication beta=-0.18, P = 0.01) with consistent effect direction. Our findings identified genus Blautia that was causally associated with CRC, thus offering novel insights into the microbiota-mediated CRC development mechanism.

Triphasic dynamic enhanced computed tomography for differentiating cholesterol and adenomatous gallbladder polyps.

BACKGROUND: Triphasic dynamic enhanced computed tomography (CT) scans were acquired to identify cholesterol and adenomatous gallbladder (GB) polyps that were inaccurately diagnosed before surgery. PURPOSE: To evaluate the CT findings of 1.0- to 2.0-cm GB polyps for differentiating between cholesterol and adenomatous polyps. METHODS: Fifty-two patients with GB polyps were treated surgically from December 2017 to July 2020 and were retrospectively divided into 2 groups according to the postoperative pathologic results: a cholesterol group with 30 patients and an adenomatous group with 22 patients. Unenhanced and triphasic dynamic enhanced CT scans were performed for all the patients within 2 weeks before surgery. The CT image parameters were measured and analyzed by 2 senior radiologists blinded to the pathological diagnoses. RESULTS: Of the 22 patients in the adenomatous group, 77.3% were female and 22.7% were male, with a mean age of 53.5 years; among the 30 patients in the cholesterol group, 66.7% were female and 33.3% were male, with a median age of 50.1 years. The CT image parameters of all 52 patients with GB polyps were analyzed. Significant differences were found in the arterial phase CT values, portal venous phase CT values, delayed phase CT values, ∆CT1 values (portal venous phase CT minus delayed phase CT values), and ∆CT2 values (arterial phase CT minus delayed phase CT values) between the cholesterol and adenomatous polyp groups (p < 0.05). In differentiating the two groups, the ∆CT1 and ∆CT2 values were superior to the arterial, portal venous and delayed phase CT values regarding both sensitivity and specificity. CONCLUSION: The arterial phase CT values, portal venous phase CT values, delayed phase CT values, and ∆CT values (including ∆CT1 and ∆CT2) from triphasic dynamic enhanced CT scans can differentiate the nature of gallbladder polypoid lesions, with the ∆CT values having the highest sensitivity and specificity.

TIGAR knockdown enhanced the anticancer effect of aescin via regulating autophagy and apoptosis in colorectal cancer cells.

Our previous study showed that TP53-induced glycolysis and apoptosis regulator (TIGAR) regulated ROS, autophagy, and apoptosis in response to hypoxia and chemotherapeutic drugs. Aescin, a triterpene saponin, exerts anticancer effects and increases ROS levels. The ROS is a key upstream signaling to activate autophagy. Whether there is a crosstalk between TIGAR and aescin in regulating ROS, autophagy, and apoptosis is unknown. In this study, we found that aescin inhibited cell viability and colony formation, and induced DNA damage, cell cycle arrest, and apoptosis in cancer cell lines HCT-116 and HCT-8 cells. Concurrently, aescin increased the expression of TIGAR, ROS levels, and autophagy activation. Knockdown of TIGAR enhanced the anticancer effects of aescin in vitro and in vivo, whereas overexpression of TIGAR or replenishing TIGAR downstream products, NADPH and ribose, attenuated aescin-induced apoptosis. Furthermore, aescin-induced ROS elevation and autophagy activation were further strengthened by TIGAR knockdown in HCT-116 cells. However, autophagy inhibition by knockdown of autophagy-related gene ATG5 or 3-methyladenine (3-MA) exaggerated aescin-induced apoptosis when TIGAR was knocked down. In conclusion, TIGAR plays a dual role in determining cancer cell fate via inhibiting both apoptosis and autophagy in response to aescin, which indicated that inhibition of TIGAR and/or autophagy may be a junctional therapeutic target in treatment of cancers with aescin.

Comparative study of outcomes of Roux-en-Y reconstruction and Billroth â reconstruction performed after radical distal gastrectomy.

BACKGROUND: Billroth Ⅰ (BⅠ) reconstruction and Roux-en-Y (RY) reconstruction are both commonly performed after distal gastrectomy (DG). We conducted a retrospective study to evaluate which is the better option. METHODS: Included in our study were 162 patients who, between April 2011 and October 2015, underwent DG followed by BⅠ reconstruction (n = 93) or RY reconstruction (n = 69). All patients were followed up for at least 1 year. We compared perioperative outcomes, postoperative complications, gastrointestinal (GI) symptoms, endoscopic findings, and nutritional status between the 2 groups of patients. RESULTS: Patient characteristics did not differ between the 2 groups, with the exception of the incidence of gastric body tumors, which was significantly higher in the RY group (73.9% vs. 19.4%; p < 0.001). Operation time was significantly longer in the RY reconstruction group (p < 0.001). There was no significant between-group difference in the grades of GI dysfunction (p = 0.122).The endoscopically determined RGB (Residual food, Gastritis, Bile reflux)scores were significantly better in the RY reconstruction group than in the BI reconstruction group (p = 0.027, p < 0.001,p < 0.001,respectively).There was also no significant between-group difference in the change (1-year postoperative value/preoperative value) in body weight, body mass index, serum albumin concentration, or total cholesterol concentration (p = 0.484,p = 0.613,p = 0.760,p = 0.890, respectively). CONCLUSIONS: RY reconstruction appears not to be advantageous over BⅠ reconstruction in terms of GI function or nutritional status 1 year after surgery. RY reconstruction does appear to be superior in terms of preventing bile reflux but takes more operation time.

Aescin-induced reactive oxygen species play a pro-survival role in human cancer cells via ATM/AMPK/ULK1-mediated autophagy.

Aescin, a natural mixture of triterpene saponins, has been reported to exert anticancer effect. Recent studies show that aescin increases intracellular reactive oxygen species (ROS) levels. However, whether the increased ROS play a role in the anticancer action of aescin remains to be explored. In this study, we demonstrated that aescin (20-80 µg/mL) dose-dependently induced apoptosis and activated mammalian target of rapamycin (mTOR)-independent autophagy in human hepatocellular carcinoma HepG2 cells and colon carcinoma HCT 116 cells. The activation of autophagy favored cancer cell survival in response to aescin, as suppression of autophagy with ATG5 siRNAs or 3-methyladenine (3-MA), a selective inhibitor of autophagy, promoted aescin-induced apoptosis in vitro, and significantly enhanced the anticancer effect of aescin in vivo. Meanwhile, aescin dose-dependently elevated intracellular ROS levels and activated Ataxia-telangiectasia mutated kinase/AMP-activated protein kinase/UNC-51-like kinase-1 (ATM/AMPK/ULK1) pathway. The ROS and ATM/AMPK/ULK1 pathway were upstream modulators of the aescin-induced autophagy, as N-acetyl-L-cysteine (NAC) or ATM kinase inhibitor (KU-55933) remarkably suppressed aescin-induced autophagy and consequently promoted aescin-induced apoptosis, whereas overexpression of ATG5 partly attenuated NAC-induced enhancement in aescin-induced apoptosis. In conclusion, this study provides new insights into the roles of aescin-mediated oxidative stress and autophagy in cancer cell survival. Our results suggest that combined administration of the antioxidants or autophagic inhibitors with aescin might be a potential strategy to enhance the anticancer effect of aescin.

Rottlerin upregulates DDX3 expression in hepatocellular carcinoma.

Rottlerin has been reported to exert its anti-tumor activity in various types of human cancers. However, the underlying molecular mechanism has not been fully elucidated. In the current study, we explored whether rottlerin exhibits its tumor suppressive function in hepatocellular carcinoma cells. Our MTT assay results showed that rottlerin inhibited cell growth in hepatocellular carcinoma cells. Moreover, we found that rottlerin induced cell apoptosis and caused cell cycle arrest at G1 phase. Furthermore, our wound healing assay result demonstrated that rottlerin retarded cell migration in hepatocellular carcinoma cells. Additionally, rottlerin suppressed cell migration and invasion. Notably, we found that rottlerin upregulated DDX3 expression and subsequently downregulated Cyclin D1 expression and increased p21 level. Importantly, down-regulation of DDX3 abrogated the rottlerin-mediated tumor suppressive function, whereas overexpression of DDX3 promoted the anti-tumor activity of rottlerin. Our study suggests that rottlerin exhibits its anti-cancer activity partly due to upregulation of DDX3 in hepatocellular carcinoma cells.

Downregulation of MACC1 inhibits the viability, invasion and migration and induces apoptosis in esophageal carcinoma cells through the phosphatase and tensin homolog/phosphoinositide 3-kinase/protein kinase B signaling pathway.

As an oncogene, MACC1 serves an important function in cancer progression and metastasis. However, the effect of MACC1 in esophageal carcinoma (EC) remains to be fully understood. The present study assessed the association between MACC1 expression and the progression of EC cells. A small interfering (si)RNA was delivered into EC cells to downregulate MACC1 expression. The MTT assay demonstrated that EC cell viability was reduced by siRNA-MACC1. Decreasing MACC1 expression increased the apoptotic rate of EC cells compared with control cells. Transwell and Matrigel assays demonstrated that EC cell migration and invasion, respectively, were downregulated by siRNA-MACC1. Furthermore, knocking down MACC1 suppressed the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway by upregulating the expression of phosphatase and tensin homolog (PTEN), a tumor suppressor. The results of the present study revealed that MACC1 expression affected cellular functions of the EC cells through the PTEN/PI3K/Akt signaling pathway. Therefore, MACC1 may potentially serve as a novel biomarker and therapeutic target for EC.

Transcription factor EB is involved in autophagy-mediated chemoresistance to doxorubicin in human cancer cells.

Transcription factor EB (TFEB) is a master regulator of autophagy activity and lysosomal biogenesis, but its role in autophagy-mediated cell survival and chemotherapy resistance is not completely understood. In this study, we explored whether TFEB played an important role in autophagy-mediated chemotherapy resistance in human cancer LoVo and HeLa cells in vitro. Treatment of human colon cancer LoVo cells with doxorubicin (0.5 µmol/L) induced autophagy activation and nuclear translocation of TFEB, which resulted from inactivation of the mTOR pathway. In both LoVo and HeLa cells, overexpression of TFEB enhanced doxorubicin-induced autophagy activation and significantly decreased doxorubicin-induced cell death, whereas knockdown of TFEB with small interfering RNA blocked doxorubicin-induced autophagy and significantly enhanced the cytotoxicity of doxorubicin. In LoVo cells, autophagy inhibition by 3-methyladenine (3-MA) or knockdown of autophagy-related gene Atg5 increased cell death in response to doxorubicin, and abolished TFEB overexpression-induced chemotherapy resistance, suggesting that the inhibition of autophagy made cancer cells more sensitive to doxorubicin. The results demonstrate that TFEB-mediated autophagy activation decreases the sensitivity of cancer cells to doxorubicin.