[Clinical factors of pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer]

Objective: To explore the feasibility of clinical factors to predict the pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer. Methods: A retrospective analysis was performed on clinical factors of 162 patients with rectal cancer, who underwent neoadjuvant chemoradiotherapy in the General Hospital of People's Liberation Army from January 2011 to December 2018.According to the postoperative pathological results, the patients were divided into pathological complete response (pCR) group and non-pathological complete response group (non-pCR group) to check the predictive clinical factors for pCR. Results: Twenty-eight cases achieved pCR after neoadjuvant chemoradiation (17.3%, 28/162). Univariate analysis showed that patients with higher differentiation (P=0.024), tumor occupation of the bowel lumen≤1/2 (P=0.006), earlier clinical T stage (P=0.013), earlier clinical N stage (P=0.009), the time interval between neoadjuvant chemoradiotherapy and surgery>49 days (P=0.006), and maximum tumor diameter≤5 cm (P=0.019) were more likely to obtain pCR, and the differences werestatistically significant. Multivariate analysis showed that tumor occupation of the bowel lumen≤1/2 (P=0.01), maximum tumor diameter≤5 cm (P=0.035), and the interval>49 days (P=0.009) were independent factors in predicting pCR after neoadjuvant therapy. Conclusion: Tumor occupation of the bowel lumen, maximum tumor diameter, and the time interval between neoadjuvant chemoradiotherapy and surgery can predict the pCR in rectal cancer.

[Influence of low dose perfluorooctanoate acid exposure to the cell proliferation, migration and invasion of the human muscle rhabdomyosarcoma cell line]

Objective: This study aimed to explore the effect of perfluorooctanoate acid (PFOA) on the proliferation, migration and invasion of the human muscle rhabdomyosarcoma RD cell line and its related mechanisms. Methods: RD cells were cultured and exposed to PFOA of different concentrations with 6-72 hours. The cell viability was assessed by cell counting kit-8 (CCK-8) assay. Wound healing and transwell filter assay were used to evaluated the migration and invasion ability of the RD cells respectively. The cell cycles were detected by Flow cytometry. Quantitative real-time PCR and Western blot were used to quantify the mRNA and protein expression difference of related genes, respectively. Results: CCK-8 assay showed that, after treated the RD cell with different dose of PFOA for 72 h, low dose PFOA (1,10,50, 100 μmol/L) promotes the proliferation of RD cells while high dose PFOA (250, 500 mol/L) inhibits the proliferation (P<0.001). Flow cytometry showed that compared with the control group, there was no significant difference in G0/G1 phase, while cells in S phase deceased and G2/M phase cells increased after treated with PFOA (50 μmol/L) for 72 h. The relative proportions of S and G2/M were significantly different between the two groups (P<0.01). The results of qPCR showed that the mRNA relative expression of CDK2 of the control group and the PFOA (50 μmol/L) group were 0.97±0.07 and 2.64±0.11 respectively, and there was a significant difference (t=12.60, P<0.001); The mRNA relative expression of cyclin E2 of the control group and the PFOA (50 μmol/L) group were 1.33±0.17 and 3.35±0.22 respectively, and there was a significant difference (t=7.42, P<0.001); The results of Western blot showed that the protein relative expression of CDK2 of the control group and the PFOA (50 μmol/L) group were 0.35±0.01 and 0.84±0.03 respectively, and there was a significant difference (t=14.60, P<0.001); The protein relative expression of cyclin E2 of the control group and the PFOA (50 μmol/L) group were 0.67±0.04 and 0.86±0.01 respectively, and there was a significant difference (t=4.88, P<0.01); There was no significant difference in the mRNA and protein expression of p21 and p53 between the PFOA and control group (P>0.05). The wound healing rate of the PFOA (50 μmol/L) group was faster than that of the control group, and the relative migration area of the PFOA group was larger accordingly (P<0.001). After PFOA (50 μmol/L) treated, the number of the cell through the membranes was much more than the control group (t=54.40, P<0.001), which means PFOA significantly stimulated the invasion ability of the RD cells. The results of qPCR showed that the mRNA relative expression of vimentin of the control group and the PFOA (50 μmol/L) group were 0.71±0.03 and 2.53±0.16 respectively, and there was a significant difference (t=11.00, P<0.001); The mRNA relative expression of MMP2 of the control group and the PFOA (50 μmol/L) group were 1.09±0.04 and 10.73±1.20 respectively, and there was a significant difference (t=8.04, P<0.001). The results of Western blot showed that the protein relative expression of vimentin of the control group and the PFOA (50 μmol/L) group were 0.55±0.06 and 0.81±0.01 respectively, and there was a significant difference (t=4.50, P<0.05). The protein relative expression of cyclin E2 of the control group and the PFOA (50 μmol/L) group were 0.64±0.04 and 1.03±0.13 respectively, and there was a significant difference (t=2.94, P<0.05). Conclusions: Low dose PFOA (50 μmol/L) exposure promotes cell proliferation, migration and invasion in the human muscle rhabdomyosarcoma cell line through inducing the expressions of MMP2, vimentin and cell cycle related genes.