RhoB expression associated with chemotherapy response and prognosis in colorectal cancer.

PURPOSE: To examine the role of RhoB expression in relation to chemotherapy response, clinical outcomes and associated signaling pathways in colorectal cancer patients. MATERIALS AND METHODS: The study included 5 colon cancer cell lines, zebrafish embryos and 260 colorectal cancer patients treated with 5-fluorouracil (5-FU) and oxaliplatin (OXL). The methods consisted of CRISPR/Cas9, reactive oxygen species (ROS), caspase-3 activity, autophagy flux, in-silico RNA sequencing and immunohistochemistry. Gene expression analysis and pathway analysis were conducted using RNA-seq data. RESULTS: All cancer lines tested, including SW480, SW480-KO13 (RhoB knockout), SW480-KO55 (RhoB knockout), HCT116 and HCT116-OE (RhoB overexpressed), exhibited cytotoxicity to 5-FU and OXL. RhoB knockout cell lines demonstrated significantly reduced migration compared to the control cell lines. Furthermore, RhoB played a role in caspase-3-dependent apoptosis, regulation of ROS production and autophagic flux. The mRNA sequencing data indicated lower expression levels of oncogenes in RhoB knockout cell lines. The zebrafish model bearing SW480-KO showed a light trend toward tumor regression. RhoB expression by immunohistochemistry in patients was increased from normal mucosa to tumor samples. In patients who received chemotherapy, high RhoB expression was related to worse survival compared to low RhoB expression. Furthermore, the molecular docking analysis revealed that OXL had a higher binding affinity for RhoB than 5-FU, with a binding affinity of -7.8 kcal/mol and HADDOCK predicted molecular interactions between RhoB and caspase 3 protein. Gene-set enrichment analysis supported these findings, showing that enrichment of DNA damage response pathway and p53 signaling in RhoB overexpression treatment group, while the RhoB knockout treatment group exhibited enrichment in the negative regulation pathway of cell migration. CONCLUSION: RhoB was negatively associated with chemotherapy response and survival in colorectal cancers. Therefore, RhoB inhibition may enhance chemotherapeutic responses and patient survival.

Computed tomography-measured body composition and survival in rectal cancer patients: a Swedish cohort study.

BACKGROUND: The association between body composition and survival in rectal cancer patients is still unclear. Therefore, we aimed to evaluate the impact of computed tomography (CT)-measured body composition on survival in rectal cancer patients, stratifying our analyses by sex, tumour location, tumour stage and radiotherapy. METHODS: This retrospective cohort study included 173 patients with rectal adenocarcinoma. CT colonography scans at the time of diagnosis were used to assess the skeletal muscle index (SMI) and the visceral adipose tissue area (VAT). The patients were divided into a low or high SMI group and a low or high VAT group according to previously defined cutoff values. Endpoints included cancer-specific survival (CSS) and overall survival (OS). RESULTS: In all patients, low SMI was associated with worse CSS (HR, 2.63; 95% CI, 1.35-5.12; P = 0.004) and OS (HR, 3.57; 95% CI, 2.01-6.34; P < 0.001) compared to high SMI. The differences remained significant after adjusting for potential confounders (CSS: adjusted HR, 2.28; 95% CI, 1.13-4.58; P = 0.021; OS: adjusted HR, 3.17; 95% CI, 1.73-5.82; P < 0.001). Low SMI was still related to a poor prognosis after stratifying by sex, tumour location, stage and radiotherapy (P < 0.05). High VAT was associated with better CSS (HR, 0.31; 95% CI, 0.11-0.84; P = 0.022) and OS (HR, 0.40; 95% CI, 0.17-0.97; P = 0.044) compared to low VAT among men with rectal cancer ≤ 10 cm from the anal verge. High VAT was associated with worse CSS (HR, 4.15; 95% CI, 1.10-15.66; P = 0.036) in women with rectal cancer ≤ 10 cm from the anal verge. CONCLUSIONS: Low SMI was associated with worse survival. High VAT predicted better survival in men but worse survival in women. The results suggest that CT-measured body composition is a useful tool for evaluating the prognosis of rectal cancer patients and demonstrate the need to include the sex and the tumour location in the analyses.

Survival benefit of statins in older patients with rectal cancer: A Swedish population-based cohort study.

OBJECTIVES: Increasing evidence suggests that statins may have antitumor effects but their role in rectal cancer appears inconclusive. The aim of this study was to investigate whether statins may have an impact on survival of older and younger patients with rectal cancer. MATERIALS AND METHODS: This study included 238 patients ≥70 years and 227 patients <70 years old, from the Southeast Health Care Region of Sweden, who were diagnosed with rectal adenocarcinoma between 2004 and 2013. RESULTS: In the older group (n = 238), statin use at the time of diagnosis was related to better cancer-specific survival (CSS) and overall survival (OS), compared to non-use (CSS: Hazard Ratio (HR), 0.37; 95% CI, 0.19-0.72; P = .003; OS: HR, 0.62; 95% CI, 0.39-0.96; P = .032). In the older group with stages I-III disease (n = 199), statin use was associated with better disease-free survival (DFS) compared to non use (HR, 0.18; 95% CI, 0.06-0.59; P = .005). The improvement of CSS, OS and DFS remained significant after adjusting for potential confounders. In the older group with stage III disease, statin users had better CSS and DFS compared to non-users (log rank P = .043; log-rank P = .028, respectively). In the older group with short course radiotherapy, statin use was related to better CSS (log-rank P = .032). No such association was present in the younger group. CONCLUSION: Statin use was related to improved survival in older patients with rectal cancer. This observation is important given the low cost and safety of statins as a drug.

SPARCL1 expression increases with preoperative radiation therapy and predicts better survival in rectal cancer patients.

PURPOSE: The secreted protein acidic and rich in cysteine-like 1 (SPARCL1) is expressed in various normal tissues and many types of cancers. The function of SPARCL1 and its relationship to a patient's prognosis have been studied, whereas its relationship to radiation therapy (RT) is not known. Our aim was to investigate the expression of SPARCL1 in rectal cancer patients who participated in a clinical trial of preoperative RT. METHODS AND MATERIALS: The study included 136 rectal cancer patients who were randomized to undergo preoperative RT and surgery (n=63) or surgery alone (n=73). The expression levels of SPARCL1 in normal mucosa (n=29), primary tumor (n=136), and lymph node metastasis (n=35) were determined by immunohistochemistry. RESULTS: Tumors with RT had stronger SPARCL1 expression than tumors without RT (P=.003). In the RT group, strong SPARCL1 expression was related to better survival than weak expression in patients with stage III tumors, independent of sex, age, differentiation, and margin status (P=.022; RR = 18.128; 95% confidence interval, 1.512-217.413). No such relationship was found in the non-RT group (P=.224). Further analysis of interactions among SPARCL1 expression, RT, and survival showed statistical significance (P=.024). In patients with metastases who received RT, strong SPARCL1 expression was related to better survival compared to weak expression (P=.041) but not in the non-RT group (P=.569). CONCLUSIONS: SPARCL1 expression increases with RT and is related to better prognosis in rectal cancer patients with RT but not in patients without RT. This result may help us to select the patients best suited for preoperative RT.