MiR-7-5p/KLF4 signaling inhibits stemness and radioresistance in colorectal cancer.

Resistance to radiotherapy remains a major unmet clinical obstacle in the treatment of locally advanced rectal cancer. Cancer stem cells (CSCs) are considered to mediate tumor development and radioresistance. However, the role of CSCs in regulating resistance to radiotherapy in colorectal cancer (CRC) remains largely unknown. We established two radioresistant CRC cell lines, HCT116-R and RKO-R, using fractionated irradiation. Analysis using miRNA sequencing and quantitative real-time PCR confirmed lower levels of miR-7-5p in both of the radioresistant cells compared to their parental cells. Subsequently, we validated that miR-7-5p expression was decreased in cancerous tissues from radiotherapy-resistant rectal cancer patients. The Cancer Genome Atlas (TCGA) database analyses revealed that low miR-7-5p expression was significantly correlated with poor prognosis in CRC patients. Overexpression of miR-7-5p led to a rescue of radioresistance and an increase in radiation-induced apoptosis, and attenuated the stem cell-like properties in HCT116-R and RKO-R cells. Conversely, knocking down miR-7-5p in parental HCT116 and RKO cells suppressed the sensitivity to radiation treatment and enhance cancer cell stemness. Stemness-associated transcription factor KLF4 was demonstrated as a target of miR-7-5p. Rescue experiments revealed that miR-7-5p/KLF4 axis could induce radiosensitivity by regulating CSCs in colorectal cancer cells. Furthermore, we used CRC tumor tissues which exhibited resistance to neoadjuvant radiotherapy to establish a patient-derived xenograft (PDX) mouse model. Tail vein injection of magnetic nanoparticles carrying miR-7-5p mimics into the PDX mice significantly inhibited tumor growth with or without irradiation treatment in vivo. Our current studies not only demonstrate an anti-cancer function of miR-7-5p in regulating CSC properties and radiosensitivity in colorectal cancer, but also provide a novel potential strategy for delaying or reverse radiation resistance in preoperative radiotherapy of CRC patients.

Decreased E2F2 Expression Correlates with Poor Prognosis and Immune Infiltrates in Patients with Colorectal Cancer.

Growing evidence has revealed that the E2F family of transcription factor 2 (E2F2) participates in the tumorigenesis and progression of various tumors, but its role in colorectal cancer (CRC) remains largely unknown. Herein, the aim of our study was to investigate the exact role of E2F2 in CRC. The expression levels of E2F2 in CRC were appraised based on the Tumor Immune Estimate Resource (TIMER), Oncomine, The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) database. The results were further confirmed using CRC tumor tissues and normal controls by experimental assays including immunohistochemistry, qRT-PCR and western blot. The survival analysis of E2F2 in CRC was analyzed using PrognoScan database and TCGA data sets. In addition, the functional roles of E2F2 were examined by Gene Set Enrichment Analysis (GSEA) and immune infiltration analysis. Our results illustrated that E2F2 was significantly downregulated in CRC samples. The low E2F2 expression in CRC was prominently correlated with N, M stage and pathological stage. Decreased E2F2 expression had an unfavorable overall survivial (OS), disease free survival (DFS), disease specific survival (DSS) and progress free interval (PFI). Multivariate cox regression showed E2F2 could be an independent prognostic factors of OS in CRC. Receiver operating characteristic (ROC) analysis showed that E2F2 may serve as a potential diagnostic biomarker for CRC patients. GSEA disclosed that E2F2 was probably involved in several pathways, including ATR pathway, ATM signalling pathway, mismatch repair, base excision repair, homologous recomibination, Fanconi Anemia pathway, multicancer invasiveness signature, and cancer stem cells. Moreover, E2F2 was significantly correlated with the infiltration level of Th2, aDC, Th17, NK CD56dim, T helper and pDC cells. The current study demonstrates that decreased E2F2 expression is closely associated with poor prognosis and immune cell infiltration in CRC, which can be a promising independent prognostic biomarker and potential treatment target for CRC.

Factors influencing the application of transrectal natural orifice specimen extraction performed laparoscopically for colorectal cancer: A retrospective study.

BACKGROUND: A few factors influence the feasibility of transrectal natural orifice specimen extraction (NOSE) surgery for colorectal cancers. However, little is known about the underlying factors of NOSE surgery. METHODS: Consecutive patients with rectal and sigmoid colon cancers treated laparoscopically between January 2014 and April 2017 were enrolled in this study. The transrectal NOSE performed laparoscopically was the first choice of all patients. When NOSE failed, the specimen was removed through a midline abdominal wall incision. Univariate and multivariate logistic regression analyses were performed to identify challenging factors influencing the intraoperative specimen extraction. RESULTS: Overall, 412 consecutive patients were included. NOSE performed laparoscopically was successful in 278 patients (75.5%) and unsuccessful in 90 patients (24.5%). The multivariate analyses indicated that body mass index (BMI; odds ratio [OR] = 3.510, 95% confidence interval [CI]: 1.333-9.243, p = 0.011), mesenteric thickness (OR = 1.069, 95% CI: 1.032-1.107, p < 0.001), maximum tumor diameter (OR = 2.827, 95% CI: 1.094-7.302, p = 0.032), and tumor T stage (OR = 2.831, 95% CI: 1.258-6.369, p = 0.012) were the factors influencing the feasibility of NOSE surgery. CONCLUSION: A successful transrectal NOSE surgery was associated with a lower BMI, thinner mesentery, lesser tumor diameter, and earlier tumor T stage.

Nomogram for predicting the feasibility of natural orifice specimen extraction after laparoscopic rectal resection.

BACKGROUND AND AIM: The goal of this study was to develop a preoperative nomogram for predicting the feasibility of trans-anal natural orifice specimen extraction (NOSE) for rectal cancer. METHODS: The analysis included 201 patients who underwent trans-anal NOSE and 457 patients who failed to undergo trans-anal NOSE in Shanghai East Hospital. The data collected included age, gender, body mass index, presence of tumor obstruction, distance from anal verge; maximum tumor diameter and anteroposterior thickness of mesorectum (AP) measured by magnetic resonance imaging; interspinous diameter, intertuberous diameter (IT), anteroposterior diameter of the inlet (API), anteroposterior diameter of the midplane, anteroposterior diameter of the outlet (APO), sacral length and pelvic depth (PD) measured by computed tomography. RESULTS: The multivariate analysis suggested that a lower body mass index (P < 0.001), no tumor obstruction (P = 0.005), a shorter distance from anal verge (P < 0.001), a smaller tumor size (P < 0.001), a thinner AP (P < 0.001), a wider and shallower bony pelvis (API/PD, P < 0.001), and a wider and shorter pelvic outlet (IT/APO, P < 0.001) were significantly associated with an increased probability of trans-anal NOSE. Successful NOSE patients had a decreased time to liquid intake (P < 0.001), a shorter postoperative hospital stay (P < 0.001), and fewer wound infections (P = 0.045). No significant difference in the rate of mortality or recurrence was observed. The nomogram model presented an area under the receiver operating characteristic curve of 0.81 (95% CI, 0.78 to 0.85) and good calibration. CONCLUSION: We developed a nomogram model that has some predicative value for the feasibility of laparoscopic rectal resection with trans-anal NOSE, utilizing clinical and radiologic parameters, available in most institutions.

Clinical efficacy and quality of life after transrectal natural orifice specimen extraction for the treatment of middle and upper rectal cancer.

BACKGROUND: Laparoscopic anterior resection with natural orifice specimen extraction (NOSE) avoids extra abdominal extraction incision during colorectal surgery. Some surgeons realized the benefits of NOSE on clinical efficacy. We compared the clinical efficacy of laparoscopic NOSE, laparoscopic non-NOSE and open surgery (OS) for short-term recovery and quality of life (QoL). METHODS: A single randomized controlled trial of NOSE for middle and upper rectal cancer between April 2014 and February 2018. Preoperative and postoperative clinical variables were analyzed and compared between the groups. Preoperative and 6 months postoperative QoL was assessed with the SF-36 QoL questionnaire. RESULTS: A total of 378 patients were enrolled, 334 patients randomly divided into NOSE group (n=104), non-NOSE group (n=119), OS group (n=111). The NOSE group was superior to the other two groups on the QoL after surgery. The NOSE group had the lowest postoperative VAS score between three groups. The postoperative time for bowel function recovery and the length of hospital stay was statistically significantly different among the three groups, with the NOSE group having the shortest time. The incidence of postoperative complications was lower in the NOSE group (12/104, 11.5%) than in the non-NOSE group (20/119, 16.8%), the difference was statistically significant. The Kaplan-Meier (K-M) survival curve showed no statistically significant difference in the disease-free survival (DFS) rate between the three groups. CONCLUSIONS: Comparing NOSE to non-NOSE and OS, the NOSE had significantly better functional recovery and better QoL. The NOSE group had a significant lower surgical complication rate than the non-NOSE group.

Transrectal Natural Orifice Specimen Extraction (NOSE) With Oncological Safety: A Prospective and Randomized Trial.

BACKGROUND: In the present paper, we introduce our experience with the novel method during laparoscopic anterior resection of upper rectal or sigmoid colon cancer by transrectal natural orifice specimen extraction (NOSE). METHODS: A prospective randomized controlled trial was performed from June 2016 to May 2019. Patients with upper rectal or sigmoid colon cancer were randomized in a 1:1 ratio to the NOSE group and the non-NOSE group. Preoperative and postoperative clinical variables were analyzed and compared between groups. Postoperative pain was analyzed utilizing a visual analog scale. Postoperative overall survival was analyzed using a Kaplan-Meier curve. RESULTS: A total of 276 patients were enrolled, of whom 254 were randomly divided into the NOSE group (n = 122) and the conventional laparoscopic group (n = 119). NOSE failed in 22 cases, which were converted to transabdominal specimen extraction. Intention-to-treat analysis was performed, and these 22 cases were included in the NOSE group. The incidence of postoperative complications was significantly lower in the NOSE group (11/122, 9%) than in the non-NOSE group (25/119, 21%). The NOSE group had a longer operation time, less blood loss, and a lower postoperative visual analog scale score than the non-NOSE group. The time for intestinal function recovery (ventilation) and the length of hospital stay were significantly longer in the non-NOSE group. The Kaplan-Meier survival curve showed no statistically significant difference in the disease-free survival rate between the NOSE group and the non-NOSE group. CONCLUSIONS: The novel NOSE method is safe and feasible to use in patients having colorectal cancer. Compared with traditional laparoscopic surgery, the postoperative complication rates of NOSE surgery were lower with an improved short-term clinical recovery.

Downregulation of miR-423-5p Contributes to the Radioresistance in Colorectal Cancer Cells.

Resistance to radiotherapy is the main reason causing treatment failure in locally advanced rectal cancer. MicroRNAs (miRNAs) have been well demonstrated to regulate cancer development and progression. However, how miRNAs regulate radiotherapy resistance in colorectal cancer remains unknown. Herein, we established two human colorectal cancer cell lines resistant to radiotherapy, named HCT116-R and RKO-R, using the strategy of fractionated irradiation. The radioresistant phenotypical changes of the two cell lines were validated by cell viability assay, colony formation assay and apoptosis assay. The miRNA expression profilings of HCT116-R and RKO-R were determined using RNA-seq analyses, and further confirmed by quantitative real-time PCR. Multiple miRNAs, including miR-423-5p, miR-7-5p, miR-522-3p, miR-3184-3p, and miR-3529-3p, were identified with altered expression in both of the radiotherapy-resistant cells, compared to the parental cells. The downregulation of miR-423-5p was further validated in the rectal cancer tissues from radiotherapy-resistant patients. Silencing of miR-423-5p in parental HCT116 and RKO cells decreased the sensitivity to radiation treatment, and inhibited the radiation-induced apoptosis. In consistence, overexpression of miR-423-5p in HCT116-R and RKO-R cells partially rescued their sensitivity to radiotherapy, and promoted the radiation-induced apoptosis. Bcl-xL (Bcl-2-like protein 1) was predicted to be a potential target gene for miR-423-5p, and miR-423-5p/Bcl-xL axis could be a critical mediator of radiosensitivity in colorectal cancer cells. The current finding not only revealed a novel role of miR-423-5p in regulating the radiosensitivity in colorectal cancer, but also suggested miR-423-5p as a molecular candidate for combination therapy with radiation to treat colorectal cancer.

International consensus on natural orifice specimen extraction surgery (NOSES) for colorectal cancer.

In recent years, natural orifice specimen extraction surgery (NOSES) in the treatment of colorectal cancer has attracted widespread attention. The potential benefits of NOSES including reduction in postoperative pain and wound complications, less use of postoperative analgesic, faster recovery of bowel function, shorter length of hospital stay, better cosmetic and psychological effect have been described in colorectal surgery. Despite significant decrease in surgical trauma of NOSES have been observed, the potential pitfalls of this technique have been demonstrated. Particularly, several issues including bacteriological concerns, oncological outcomes and patient selection are raised with this new technique. Therefore, it is urgent and necessary to reach a consensus as an industry guideline to standardize the implementation of NOSES in colorectal surgery. After three rounds of discussion by all members of the International Alliance of NOSES, the consensus is finally completed, which is also of great significance to the long-term progress of NOSES worldwide.

Long-Term Oncological Outcomes of Endoscopic Stenting as a Bridge to Surgery Versus Emergency Surgery for Malignant Colorectal Obstruction: A Comparative Study.

AIM: With consideration of the theoretical link between the stent insertion and the increased risk of tumor cells spillaged, which may lead to distant metastases, there is a concern about long-term clinical outcomes after the usage of self-expanding metallic stents (SEMS) as a "bridge to surgery" in the malignant colorectal obstruction (MCO) treatment. This cohort study aimed to compare the long-term oncological outcomes of SEMS as a bridge to surgery (SEMS group) with those of emergency surgery (ES group) for MCO. METHODS: Twenty-seven patients who underwent semielective curative resection after endoscopic SEMS insertion were included from October 2007 to December 2012 in the SEMS group were compared with 33 patients who underwent emergency curative surgery for MCO during the same period in the ES group. The clinical pathologic characteristics and the overall survival (OS) rate were compared between the two groups. RESULTS: There were no significant differences in demographics, tumor stage, location, and histology between the SEMS and ES groups. The median OS times were 37 months for the SEMS group and 23 months for the ES group. The proportions of patients who received postoperative adjuvant chemotherapy were comparable (SEMS group versus ES group, 70.4% versus 45.5%; P = .138). There were no significant differences in terms of the long-term oncological outcome between two groups in the 3-year OS rate (55.6% versus 39.4%; P = .2119) and the 5-year OS rate (48.1% versus 36.4%; P = .3570). CONCLUSIONS: Long-term oncological outcomes of the SEMS group were comparable to those of the ES group.

HIF-1α activates hypoxia-induced BCL-9 expression in human colorectal cancer cells.

B-cell CLL/lymphoma 9 protein (BCL-9), a multi-functional co-factor in Wnt signaling, induced carcinogenesis as well as promoting tumor progression, metastasis and chemo-resistance in colorectal cancer (CRC). However, the mechanisms for increased BCL-9 expression in CRC were not well understood. Here, we report that hypoxia, a hallmark of solid tumors, induced BCL-9 mRNA expression in human CRC cells. Analysis of BCL-9 promoter revealed two functional hypoxia-responsive elements (HRE-B and HRE-C) that can be specifically bound with and be transactivated by hypoxia inducible factors (HIF) -1α but not HIF-2α. Consistently, ectopic expression of HIF-1α but not HIF-2α transcriptionally induced BCL-9 expression levels in cells. Knockdown of endogenous HIF-1α but not HIF-2α by siRNA largely abolished the induction of HIF by hypoxia. Furthermore, there was a strong association of HIF-1α expression with BCL-9 expression in human CRC specimens. In summary, results from this study demonstrated that hypoxia induced BCL-9 expression in human CRC cells mainly through HIF-1α, which could be an important underlying mechanism for increased BCL-9 expression in CRC.

Endoscopic submucosal dissection versus transanal local excision for rectal carcinoid: a comparative study.

AIM: The aim of this study is to compare the short-term clinical outcomes between endoscopic submucosal dissection and transanal local excision for rectal carcinoid tumors. METHODS: Between 2007 and 2012, 31 patients with rectal carcinoid underwent endoscopic submucosal dissection at our hospital. They were compared with a matched cohort of 23 patients who underwent transanal local excision for rectal carcinoid between 2007 and 2012. Short-term clinical outcomes including surgical parameters, postoperative recovery, and oncologic outcomes were compared between the two groups. RESULTS: The mean size of tumors was significantly bigger in the transanal local excision group (0.8 ± 0.2 versus 1.1 ± 0.5 cm; P = 0.018). En bloc resection was achieved for 30 patients (97 %) in the endoscopic submucosal dissection group and all the patients in the transanal local excision group. The operation time was longer in the transanal local excision than that in the endoscopic submucosal dissection group (40.0 ± 22.7 min versus 12.2 ± 5.3 min; P < 0.001). Complications in the transanal local excision group were five cases of acute retention of urine. There was no local recurrence or distant metastasis in either group during the follow-up period. CONCLUSION: For the treatment of rectal carcinoid tumors with diameter <1 cm, endoscopic submucosal dissection has better short-term clinical outcomes than transanal local excision in terms of faster recovery and possibly a lower morbidity rate. Transanal local excision may be the first therapeutic choice of scar-embedded rectal carcinoid tumors.

miR-320b suppresses cell proliferation by targeting c-Myc in human colorectal cancer cells.

BACKGROUND: MicroRNAs (miRNAs) are small noncoding RNAs that potentially play a critical role in tumorigenesis. Mounting evidence indicates that one specific miRNA: miR-320b is down regulated in numerous human cancers, including colorectal cancer (CRC); making the hypothesis that miR-320b may play a key role in tumorigenesis plausible. However, its role in carcinogenesis remains poorly defined. The goal of this study is to better clarify the role of miR-320b in tumor growth of CRC. METHODS: Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was conducted to detect the expression of miR-320b in CRC tissues and 5 CRC cell lines. The effect of miR-320b on cell proliferation was analyzed in vitro and in vivo. Furthermore, a luciferase reporter assay was performed to measure the target effects of miR-320b. Lastly, the messenger RNA (mRNA) and protein levels of the gene c-MYC were measured in CRC cell lines and tissues by qRT-PCR, and confirmed via Western blot and Immunohistochemical (IHC) staining. RESULTS: The results presented here showed that miR-320b expression was down regulated in both CRC tissues and cells. Overexpression of miR-320b in CRC cells was statistically correlated with a decrease of cell growth in vitro and in vivo, while c-MYC was identified as a target gene of miR-320b in CRC. Furthermore, it was found that up-regulation of c-Myc can attenuate the effects induced by miR-320b. CONCLUSIONS: Our identification of c-MYC as a target gene of miR-320b provides new insights into the pathophysiology of CRC proliferation, and identifies miR-320b as a novel therapeutic target for the treatment of CRC.

Upregulation of nemo-like kinase is an independent prognostic factor in colorectal cancer.

AIM: To investigate the expression and oncogenic role of nemo-like kinase (NLK) in colorectal cancer. METHODS: Expression of NLK protein was assessed by immunohistochemistry in tissue specimens from 56 cases of normal colorectal mucosa, 51 cases of colorectal adenoma, and 712 cases of colorectal cancer. In addition, NLK expression was knocked down using a lentivirus carrying NLK small hairpin RNA in colorectal cancer cells. Cell viability methylthiazoletetrazolium assays, colony formation assays, flow cytometry cell cycle assays, Transwell migration assays, and gene expression assays were performed to explore its role on proliferation and migration of colorectal cancer. RESULTS: Expression of NLK protein progressively increased in tissues from the normal mucosa through adenoma to various stages of colorectal cancer. Overexpression of NLK protein was associated with advanced tumor-lymph node-metastasis stages, poor differentiation, lymph node and distant metastases, and a higher recurrence rate of colorectal cancer (P < 0.05). Multivariate analyses showed that NLK expression was an independent prognostic factor to predict overall survival (hazard ratio 2.57, 95% confidence interval: 1.66-3.98; P < 0.001) and disease-free survival (hazard ratio 1.96, 95% confidence interval: 1.40-2.74: P < 0.001) of colorectal cancer patients. Furthermore, knockdown of NLK expression in colorectal cancer cell lines reduced cell viability, colony formation, and migration, and arrested tumor cells at the G0/G1 phase of the cell cycle. At the gene level, knockdown of NLK expression inhibited matrix metalloproteinase-2 expression in colorectal cancer cells. CONCLUSION: NLK overexpression is an independent prognostic factor in colorectal cancer and knockdown of NLK expression inhibits colorectal cancer progression and metastasis.

Expression of ITGB1 predicts prognosis in colorectal cancer: a large prospective study based on tissue microarray.

BACKGROUND: ITGB1 is a heterodimeric cell-surface receptor involved in cell functions such as proliferation, migration, invasion and survival. The aim of this study was to assess ITGB1 expression in colorectal cancer and correlate it with clinicopathological features, as well as to evaluate its potential prognostic significance. MATERIALS AND METHODS: In this study, we examined the expression of ITGB1 using tissue microarrays containing analyzed specimens by immunohistochemistry. ITGB1 expression was further correlated with clinicopathological and prognostic data. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests. A multivariate study with the Cox's proportional hazard model was used to evaluate the prognostic aspects. RESULTS: ITGB1 expression was present in 88.5% of the analyzed specimens. Significant differences in ITGB1 expression were found between normal mucosa and carcinomas (P<0.001). High ITGB1 expression was associated with poor prognosis, and it independently correlated with shortened overall survival and disease-free survival in colorectal cancer patients (P<0.001). More so, ITGB1 expression, bowel wall invasion, lymph node metastasis and distant metastasis were independent prognostic factors for overall survival. Additionally, significant differences in ITGB1 expression were observed in adenomas and tumors from patients with familial adenomatous polyposis compared to normal colon mucosa (P<0.05) CONCLUSION: The results of this study indicate that ITGB1 overexpression in colorectal tumors is associated with poor prognosis, as well as aggressive clinicopathological features. Therefore, ITGB1 expression could be used as potential prognostic predictor in colorectal cancer patients.

Predictive Factors for Surgical Intervention in Patients over the Age of 80 with Adhensive Small-Bowel Obstruction.

Adhensive small-bowel obstruction (SBO) remains a common cause of admission to surgical wards around the world. Given the growing elderly population, the number of elderly patients with adhensive SBO can be expected to increase substantially. Timely and appropriate treatment would improve morbidity and mortality rates in elderly patients with adhensive SBO. However, accurately determining which patients should undergo surgical treatment during the hospitalization remains difficult. The aim of this study was to identify predictive factors for surgical intervention in patients aged over 80 years presenting with SBO due to postoperative adhesions. A clinical and radiological data for the assessment of patients presenting with adhensive SBO were collected. A logistic regression model was applied to identify risk factors that would predict the need of surgical intervention. A total of 21 patients (13 males, 8 females) were treated during a 3.5-year period. The mean age was 85.5 ± 4.7 years, ranging from 80 to 97 years. There is no significant difference in age (group 1 87.6 ± 5.9 years vs. group 2 84.8 ± 4.3 years, p = 0.262) between two groups. Serious coexisting diseases were noted in 13 (61.9 %, 13/21) patients. Primary hypertension, cardiac diseases, and diabetes mellitus were common coexisting conditions. However, there is no significant difference in comorbidities (40 vs. 68.8 %, p = 0.325) between group 1 and group 2. Adhensive SBO was successfully treated with conservative treatment in 16 patients (76.2 %, 16/21, group 2), whereas conservative treatment failed in 5 patients (23.8 %, 5/21, group 1), who subsequently underwent laparotomy. Postoperative complication rate was 14.3 % (wound infection, 1/5) and mortality was 0 % (0/5) in group 1. One patient death was recorded in group 2 (1/16, 6.3 %). The overall mean hospital stay was 10.0 ± 5.9 days (range 3-27 days). Group 1 had a longer hospital stay than group 2. However, the difference did not reach the significant level (12.8 ± 8.2 vs. 9.1 ± 5.9 days, p = 0.274). On univariate analysis, the need for surgical intervention was significantly associated with granulocyte percentage (2.768, 0.961-7.975, p = 0.059), CT findings of free intraabdominal fluid (28.000, 1.988-394.405, p = 0.014), and level of albumin (0.265, 0.073-0.970, p = 0.045). On multivariate analysis, the predictive factor was free intraabdominal fluid (28.000, 1.988-394.405, p = 0.014). Conservative treatment remains a major consideration in patients over the age of 80. Although major cases of adhensive SBO are successfully treated with conservative methods, some fail to respond, and the independent risk factor for surgical indication is free intraabdominal fluid.

[Cloning, expression and immuno-protection analysis of a gene encoding troponin T of Schistosoma japonicum (SjTnT)].

OBJECTIVE: To clone cDNA encoding troponin T of Schistosoma japonicum (SjTnT), and evaluate the protective efficacy induced by recombinant SjTnT in BALB/c mice against S. japonicum challenge infection. METHODS: The SjTnT gene was amplified from 28-day-schistosome cDNAs by PCR and then subcloned into pET28a(+). The recombinant SjTnT protein (rSjTnT) was expressed in Escherichia coli BL21 (DE3) cells. The serum specific to rSjTnT was prepared by immunized BALB/c mice with the recombinant antigen, and the immunogenicity of rSjTnT was detected by Western blotting and ELISA. The immuno-protective efficacy induced by rSjTnT in BALB/c mice was evaluated according to the reduction in worm and egg counts. RESULTS: The cDNA encoding SjTnT was successfully cloned and expressed in E. coli. Western blotting showed that rSjTnT had a good immunogenicity. The high level of specific IgG antibodies was detected, and 33.89% worm reduction and 43.94% liver egg reduction were obtained in mice vaccinated with rSjTnT combined with Seppic 206 adjuvant compared with those in the adjuvant control group. CONCLUSIONS: rSjTnT could induce partial immuno-protection against S. japonicum infection in BALB/c mice. This study provided a basic for understanding the biological function of SjTnT.

Risk factors associated with sphincter-preserving resection in patients with low rectal cancer.

Abdominoperineal resection (APR) and sphincter-preserving resection (SPR) are the two primary surgical options for rectal cancer. Retrospectively we collected rectal cancer patients for SPR and APR observation between 2005 and 2007. The patient-related, tumor-related, and surgery-related variables of the SPR and APR groups were analyzed by using logistic regression techniques. The mean distance from the anal verge (DAV) of cancer is significantly higher in SPR than that in APR (P<0.001). In cancers with DAV<40 mm (SPR, 40 versus APR, 110), multivariate analysis shows that surgeon procedure volume (odds ratio [OR]=0.244; 95% confidence interval [CI]: 0.077-0.772; P=0.016) and neoadjuvant radiotherapy (OR=0.031; 95% CI: 0.002-0.396; P=0.008) are factors influencing SPR. In cancers with DAV ranging from 40 mm to 59 mm (SPR 190 versus APR 50), analysis shows that patient age (OR=2.139; 95% CI: 1.124-4.069; P=0.021), diabetes (OR=2.657; 95% CI: 0.872-8.095; P=0.086), and colorectal surgeon (OR=0.122, 95% CI: 0.020-0.758; P=0.024), are influencing factors for SPR. The local recurrence and disease-free survival reveal no significant difference. A significant difference exists in DAV, surgeon specialization, procedure volume, age, diabetes, and neoadjuvant radiotherapy between SPR and APR.

Incidence and mortality of anastomotic dehiscence requiring reoperation after rectal carcinoma resection.

Anastomotic dehiscence (AD) requiring reoperation is the most severe complication following anterior rectal resection. We performed a systematic review on studies that describe AD requiring reoperation and its subsequent mortality after anterior resection for rectal carcinoma. A systematic search was performed on published literature. Data on the definition and rate of AD, the number of ADs requiring reoperation, the mortality caused by AD, and the overall postoperative mortality were pooled and analyzed. A total of 39 studies with 24,232 patients were analyzed. The studies varied in incidence and definition of AD. Systematic review of the data showed that the overall rate of AD was 8.6%, and the rate of AD requiring reoperation was 5.4%. The postoperative mortality caused by AD was 0.4%, and the overall postoperative mortality was 1.3%. We found considerable risk and mortality for AD requiring reoperation, which largely contributed to the overall postoperative mortality.

[Association of epithermal growth factor receptor expression and its downstream gene mutation status with radiosensitivity of colorectal carcinoma cell lines in vitro].

OBJECTIVE: To investigate the effect of epithermal growth factor receptor (EGFR) expression and K-ras, B-raf and PIK3CA mutation status on the radiosensitivity of human colorectal carcinoma (CRC) cell lines in vitro. METHODS: Real-time RT-PCR was used to measure EGFR mRNA expression in nine human CRC cell lines, and K-ras, B-raf and PIK3CA mutation status of each CRC cell line was also identified respectively. After treatment with irradiation at graded dose, the cell viability was measured by clonogenic survival assay. The rate of cell apoptosis and cell cycle distribution were tested by flow cytometry. The cell morphology was observed with hoechst 33258 staining to analyze the correlation between EGFR mRNA expression and radiosensitivity of CRC cell lines. RESULTS: A positive correlation between EGFR mRNA expression and survival fraction of 2 Gy(SF2) was observed (r=0.717, P=0.030). Association was also identified between the mutation status of PIK3CA and radiosensitivity (t=2.401, P=0.047), while mutation status of K-ras and B-raf was not associated with radiosensitivity. At 48-hour after exposing to irradiation, the apoptosis rate of radiosensitive cell line (HCT116) was significantly increased in a dose-dependent manner (P<0.05), while the apoptosis rate of radioresistant cell line (HT29) was significantly increased only when radiation dose increased to 6 Gy. The ratio of G0/G1 phase was reduced significantly with the increase of radiation dose in radiosensitive cell line (HCT116, P<0.05), while this trend was not observed in radioresistant cell line (HT29, P>0.05). CONCLUSIONS: Over-expression of EGFR mRNA is correlated to radioresistance of human CRC cell lines, and mutation status of PIK3CA is closely related with radiosensitivity of CRC cells. The inhibition of apoptosis and G0/G1 arrest may induce the radioresistance of CRC cell lines.