LncRNA OTUD6B-AS1 overexpression promoted GPX4-mediated ferroptosis to suppress radioresistance in colorectal cancer

Background Radiotherapy is widely employed in colorectal cancer (CRC) treatment but is often compromised by developed radioresistance. This study explored the mechanism of long non-coding RNA ovarian tumor domain containing 6B-antisense RNA1 (lncRNA OTUD6B-AS1) in CRC radioresistance through tripartite motif 16 (TRIM16). Methods CRC and non-cancerous tissues were collected and radioresistant CRC cells were established, with real-time quantitative polymerase chain reaction to determine gene expression in tissues and cells. Radioresistance was evaluated by cell counting kit-8 assay and immunofluorescence (γ-H2AX) and ferroptosis was tested by Western blot assay (ACSL4/GPX4) and assay kits (Fe2+/ROS/MDA/GSH). The association between ferroptosis and lncRNA OTUD6B-AS1-inhibited radioresistance was testified using ferroptosis inhibitor. The subcellular localization of lncRNA OTUD6B-AS1 was tested by the nuclear/cytoplasmic fractionation assay, with RNA immunoprecipitation assay to validate gene interactions. Rescue experiments were conducted to analyze the role of TRIM16 in CRC radioresistance. Results LncRNA OTUD6B-AS1 and TRIM16 were poorly expressed (P < 0.01) in CRC tissues and cells and further decreased (P < 0.01) in radioresistant CRC cells. OTUD6B-AS1 overexpression decreased cell survival (P < 0.01), increased γ-H2AX levels (P < 0.01), and elevated ferroptosis and oxidative stress (P < 0.01) after X-ray radiation. Ferroptosis inhibitor attenuated radioresistance (P < 0.01) caused by lncRNA OTUD6B-AS1 overexpression. LncRNA OTUD6B-AS1 stabilized TRIM16 mRNA via binding to HuR. TRIM16 knockdown reduced ferroptosis and increased radioresistance (P < 0.05). Conclusion OTUD6B-AS1 overexpression stabilized TRIM16 via binding to HuR and increased GPX4-mediated ferroptosis, thus attenuating CRC radioresistance. Our study provided a new rationale for the treatment of CRC (AU)

LncRNA OTUD6B-AS1 overexpression promoted GPX4-mediated ferroptosis to suppress radioresistance in colorectal cancer.

BACKGROUND: Radiotherapy is widely employed in colorectal cancer (CRC) treatment but is often compromised by developed radioresistance. This study explored the mechanism of long non-coding RNA ovarian tumor domain containing 6B-antisense RNA1 (lncRNA OTUD6B-AS1) in CRC radioresistance through tripartite motif 16 (TRIM16). METHODS: CRC and non-cancerous tissues were collected and radioresistant CRC cells were established, with real-time quantitative polymerase chain reaction to determine gene expression in tissues and cells. Radioresistance was evaluated by cell counting kit-8 assay and immunofluorescence (γ-H2AX) and ferroptosis was tested by Western blot assay (ACSL4/GPX4) and assay kits (Fe2+/ROS/MDA/GSH). The association between ferroptosis and lncRNA OTUD6B-AS1-inhibited radioresistance was testified using ferroptosis inhibitor. The subcellular localization of lncRNA OTUD6B-AS1 was tested by the nuclear/cytoplasmic fractionation assay, with RNA immunoprecipitation assay to validate gene interactions. Rescue experiments were conducted to analyze the role of TRIM16 in CRC radioresistance. RESULTS: LncRNA OTUD6B-AS1 and TRIM16 were poorly expressed (P < 0.01) in CRC tissues and cells and further decreased (P < 0.01) in radioresistant CRC cells. OTUD6B-AS1 overexpression decreased cell survival (P < 0.01), increased γ-H2AX levels (P < 0.01), and elevated ferroptosis and oxidative stress (P < 0.01) after X-ray radiation. Ferroptosis inhibitor attenuated radioresistance (P < 0.01) caused by lncRNA OTUD6B-AS1 overexpression. LncRNA OTUD6B-AS1 stabilized TRIM16 mRNA via binding to HuR. TRIM16 knockdown reduced ferroptosis and increased radioresistance (P < 0.05). CONCLUSION: OTUD6B-AS1 overexpression stabilized TRIM16 via binding to HuR and increased GPX4-mediated ferroptosis, thus attenuating CRC radioresistance. Our study provided a new rationale for the treatment of CRC.

[Study of postoperative anorectal dynamics in ultra-low rectal cancer patients undergoing laparoscopic intersphincteric resection].

OBJECTIVE: To study postoperative anorectal dynamic change in ultra-low rectal cancer patients undergoing laparoscopic intersphincteric resection. METHODS: Clinical and follow-up data of 26 ultra-low rectal cancer patients undergoing laparoscopic intersphincteric resection in our department from January 2007 to January 2013 were retrospectively analyzed (observation group). Thirty rectal cancer patients undergoing laparoscopic low anterior resection by the same surgical team in the same period from the Medical Record Room were randomly extracted as control group. The observation indexes included preoperative and postoperative anal resting pressure(ARP), anal maximum squeeze pressure (AMSP), rectal maximum tolerable volume (RMTV), rectal anal inhibition reflex (RAIR) and Wexner anal function scores (0 means normal). RESULTS: There were no significant differences in clinical baseline data between the two groups(all P>0.05), except the distance from lower edge of tumor to dentate line [(2.9±0.4) cm in observation group vs. (5.0±0.5) cm in control group, P=0.000]. There were no differences in preoperative anorectal manometry and Wexner anal function score between two groups (all P>0.05). The average follow-up time in observation group and control group was 14.5 months and 14.0 months respectively. Three months after operation, significant differences between observation group and control group (all P=0.000) were as follows: defecation frequency [(6.0±1.5) times/day vs. (2.5±1.0) times/day], Wexner anal function score(5.0±0.9 vs. 2.9±1.2), ARP [(32.0±6.7) mmHg vs. (45.0±8.2) mmHg], AMSP [(90.1±6.9) mmHg vs. (110.0±7.5) mmHg], RMTV [(61.0±7.2) ml vs. (91.1±7.5) ml] and positive rate of RAIR [11.5%(3/26) vs. 66.7%(20/30)]. One year after surgery, there were no significant differences in defecation frequency, Wexner anal function scores, ARP, AMSP and RMTV between the two groups (all P>0.05), however the difference in positive rate of RAIR was still significant[38.5%(10/26) vs. 93.3%(28/30), P=0.000]. CONCLUSION: Laparoscopic intersphincteric resection for ultra- low rectal cancer can achieve satisfactory anorectal dynamic effect.

Comparison of laparoscopic subtotal colectomy with posterior vaginal suspension and laparoscopic subtotal colectomy with transvaginal repair for patients with slow-transit constipation complicated with rectocele: a non-randomized comparative study in a single center.

BACKGROUND: Slow-transit constipation complicated with rectocele is a mixed constipation difficult to treat by surgery. Different hospitals and surgeons may employ different surgical procedures. The present study aims to compare the efficacy of laparoscopic subtotal colectomy (LSC) with posterior vaginal suspension and LSC with transvaginal repair for patients having refractory slow-transit constipation complicated with rectocele. METHODS: This paper is a retrospective study of 64 patients having refractory slow-transit constipation complicated with rectocele. Admitted from January 2002 to December 2012, the 64 patients were non-randomly divided into two groups: patients who underwent LSC with posterior vaginal suspension (Group A, 36 patients) and patients who underwent LSC with transvaginal repair (Group B, 28 patients). RESULTS: There was no statistically significant difference (P > 0.05) in preoperative general characteristics and Wexner constipation score between Group A and Group B. There was no statistically significant difference (P > 0.05) in operative time and intraoperative blood loss between the two groups. One month after the surgery, there was no statistically significant difference (P > 0.05) in early postoperative complications, constipation recurrence rate, degree of improvement in constipation symptoms, and Wexner constipation score between the two groups. But 1-year follow-up results show that there was statistically significant difference (P < 0.05) in constipation recurrence rate, gastrointestinal quality of life index, the degree of improvement in constipation symptoms, and Wexner constipation score between the two groups. CONCLUSION: Compared with the LSC with transvaginal repair, the LSC with posterior vaginal suspension demonstrated better efficacy in treating refractory slow-transit constipation complicated with rectocele.