Preventing anastomotic leakage (AL) is crucial for colorectal surgery. Some studies have suggested a positive role of transanal drainage tubes (TDTs) in AL prevention after low anterior resection, but this finding is controversial.OBJECTIVE To assess the effect of TDTs in AL prevention after laparoscopic low anterior resection for rectal cancer. DESIGN, SETTING, AND PARTICIPANTSThis multicenter randomized clinical trial with parallel groups (TDT vs non-TDT) was performed from February 26, 2016, to September 30, 2020. Participants included patients from 7 different hospitals in China who were undergoing laparoscopic low anterior resection with the double-stapling technique for mid-low rectal cancer; 576 patients were initially enrolled in this study, and 16 were later excluded. Ultimately, 560 patients were randomly divided between the TDT and non-TDT groups.INTERVENTIONS A silicone tube was inserted through the anus, and the tip of the tube was placed approximately 5 cm above the anastomosis under laparoscopy at the conclusion of surgery. The tube was fixed with a skin suture and connected to a drainage bag. The TDT was scheduled for removal 3 to 7 days after surgery. MAIN OUTCOMES AND MEASURESThe primary end point was the postoperative AL rate within 30 days. RESULTSIn total, 576 patients were initially enrolled in this study; 16 of these patients were excluded. Ultimately, 560 patients were randomly divided between the TDT group (n = 280; median age, 61.5 years [IQR, 54.0-68.8 years]; 177 men [63.2%]) and the non-TDT group (n = 280; median age, 62.0 years [IQR, 52.0-69.0 years]; 169 men [60.4%]). Intention-to-treat analysis showed no significant difference between the TDT and non-TDT groups in AL rates (18 [6.4%] vs 19 [6.8%]; relative risk, 0.947; 95% CI, 0.508-1.766; P = .87) or AL grades (grade B, 14 [5.0%] and grade C, 4 [1.4%] vs grade B, 11 [3.9%] and grade C, 8 [2.9%]; P = .43). In the stratified analysis based on diverting stomas, there was no significant difference in the AL rate between the groups, regardless of whether a diverting stoma was present (without stoma, 12 [5.8%] vs 15 [7.9%], P = .41; and with stoma, 6 [8.3%] vs 4 [4.5%], P = .50). Anal pain was the most common complaint from patients in the TDT group (130 of 280, 46.4%). Accidental early TDT removal occurred in 20 patients (7.1%), and no bleeding or iatrogenic colonic perforations were detected. CONCLUSIONS AND RELEVANCEThe results from this randomized clinical trial indicated that TDTs may not confer any benefit for AL prevention in patients who undergo laparoscopic low anterior resection for mid-low rectal cancer without preoperative radiotherapy.

Cancer stem cells (CSCs) are a key target for reducing tumor growth, metastasis, and recurrence. Redox status is a critical factor in the maintenance of CSCs, and the antioxidant enzyme Peroxiredoxin 2 (Prdx2) plays an important role in the development of colon cancer. Therefore, we investigated the contribution of Prdx2 to the maintenance of stemness of colon CSCs. Here, we used short-hairpin RNAs and a Prdx2-overexpression vector to determine the effects of Prdx2. We demonstrated that knockdown of Prdx2 reduced the self-renewal and sphere formation and resulted in increased 5-FU-induced apoptosis in human colon CSCs. Prdx2 overexpression induced reversion of the self-renewal and sphere formation. Furthermore, the effects of Prdx2 resulted in an altered expression of stemness associated with the Hh/Gli1 signaling pathway. Finally, knockdown of Prdx2 in CD133+ cells reduced the volume of xenograft tumors in BALB/c-nu mice. Taken together, colon CSCs overexpress Prdx2, which promotes their stem cell properties via the Hh/Gli1 signaling pathway. The results suggest that Prdx2 may be an effective therapeutic target for the elimination of CSCs in colorectal cancer.

The mammalian peroxiredoxin 2 (Prdx2) is a member of thiol-dependent antioxidant proteins and plays an important role in the progression of colorectal cancer (CRC). The aim of this study was to confirm the role of Prdx2 in formation of VM and progression of CRC. Immunohistochemistry and CD34/periodic acid Schiff double staining were performed to explore the expression of Prdx2 and VM formation in 70 CRC tissues, and there was a positive correlation between Prdx2 expression and VM formation by the Pearson correlation coefficient (r = 0.282, p < 0.05). Prdx2 was suppressed in poorly differentiated HCT116 cells by Prdx2-siRNA-LV transduction. The expression of Prdx2 at both mRNA and protein levels in HCT116 cells transfected with the Prdx2 siRNA was significantly lower than that of negative control siRNA as confirmed by quantitative real-time PCR and Western blotting analysis, respectively (p < 0.05). The well-established in vitro 3D culture model was chosen to investigate the VM formation of HCT116 cells. The numbers of the tubular structures were significantly fewer in Prdx2 siRNA explants than those of negative control siRNA explants after VEGF induction (p < 0.05). Although VEGFR2 expressions had no change after VEGF induction, we found that VEGFR2 phosphorylation levels were markedly reduced in cells of siPrdx2 over time compared with those of negative control siRNA by Western blotting analysis (p < 0.05, p < 0.01). The effects of Prdx2 siRNA on the invasive capabilities of HCT116 cells with VEGF induction were examined by using Matrigel invasion chamber assay. The invasive capabilities of HCT116 cells were significantly declined in Prdx2 siRNA explants than those of negative control siRNA explants (p < 0.05). The effects of Prdx2 siRNA on pathological tumor growth were examined by using a tumor xenograft model in vivo. After implant of HCT116 cells that transduced with Prdx2 siRNA and negative control siRNA as xenografts into nude mice, the growth of xenograft tumors with Prdx2 siRNA was much slower than that of negative control siRNA, and the volumes of tumor xenografts with Prdx2 siRNA were smaller than those of negative control siRNA after 5 weeks (p < 0.05). Further conclusion showed that Prdx2 regulates VM formation by targeting VEGFR2 activation, which now represents as a therapeutic target for RC.

Hypoxia is a typical feature of colon cancer occurrence and progression. We have reported that high expression and activity of PhospholipaseD2 (PLD2) induced by hypoxia in colon cancer cells. In order to further investigate the role of PLD2 in colon cancer under hypoxic conditions. MTT assay was used to detect the proliferation of human colon cancer cells (SW480 and SW620) under hypoxic conditions by decrease the PLD2 gene expression or inhibit the activity of PLD2. Expression level of p-P65/T-P65 and Cyclin D1 were detected in those cells treated as above through using western blot and RT-PCR analysis. Effect of NF-Bp65 inhibitor (BAY-117082) on the proliferation and expression level of Cyclin D1 and PLD2 of colon cancer cells under hypoxic conditions were further analysised. As a result, decreased the expression of PLD2 or inhibited the activity of PLD2 leaded to the proliferation of hypoxia colon cancer cells reduced, and along with the expression level of p-P65/T-P65 and Cyclin D1 reduced. However, inhibition the expression level of p-P65/T-P65 lead to the proliferation and expression of Cyclin D1 in those hypoxia colon cancer cells also reduced. In vivo growth decreased in response to PLD2 and NF-Bp65 inhibition. Our study indicates that high expression of PLD2 induced by hypoxia promotes the proliferation of colon cancer cells, and it may elevate the expression level of Cyclin D1 through activating NF-Bp65 signaling pathway. Inhibition of the PLD2 expression may provide a new clue for treatment for colon cancer.