Effect and mechanism of phosphorylation modification of Thr592 site in SAMHD1 protein on gastric cancer / 安徽医科大学学报

Objective @#To elucidate the effect of phosphorylation modification at the threonine 592 (Thr592) site on the inhibition of gastric cancer proliferation by sterile alpha motifs and HD structural domain－containing protein 1 (SAMHD1) and the potential mechanism of action．@*Methods@# Post-translational modifications (PTMs) of SAMHD1 protein in gastric cancer tissues and cell lines in the database were analyzed，and immunohistochemical stai- ning was performed to detect SAMHD1 Thr592 phosphorylation in paired tissues of gastric cancer patients．In gastric cancer cells，SAMHD1 Thr592 variants were constructed and transiently transfected，and cell proliferation was detected using the cell counting kit 8 ( CCK-8 ) method． The phosphorylation of the cyclin-dependent kinases ( CDK) 2 protein threonine 160 (Thr160) site was inhibited by the addition of different concentrations of the CDK6 inhibitor，Palbociclib，which reduced the level of SAMHD1 protein Thr592 phosphorylation．Three online databases were used to analyze the SAMHD1 reciprocal proteins and take the intersection to derive the Nik-related kinase (NRK) protein．Immunoprecipitation ( Co-IP) ，mass spectrometry and Western blot were used to verify the interactions between SAMHD1 and NRK proteins and detect the effect of NRK on the phosphorylation of the SAMHD1 Thr592 site. @*Results @#Compared with PTMs such as ubiquitination，the highest level of phosphorylation modification of SAMHD1 was observed in tumors，and the difference was statistically significant (P＜0. 01) ．Immunohistochemical experiments showed that phosphorylated SAMHD1 (Thr592) was expressed higher in gastric adenocarcinoma than that in normal mucosal tissue adjacent to the cancer，and the difference was statistically significant (P < 0. 01) ．Western blot assay showed that SAMHD1 protein expression was elevated in MKN-45 cells in the overexpression wild type and mutant groups ，and phosphorylated SAMHD1 levels were also elevated in the wild type， T592E and HD / AA groups． CCK-8 assay showed that both SAMHD1 wild type and T592A could inhibit gastric cancer cell proliferation，while T592E and HD / AA had no effect on gastric cancer proliferation． On the basis of overexpression of SAMHD1，CCK-8 suggested that cell proliferation was inhibited after adding different concentrations of Palbociclib treatment，and Western blot assay suggested that the phosphorylation level was also reduced. NRK protein was obtained by Co-IP and mass spectrometry identification to screen the SAMHD1 reciprocal protein profile and database intersection，and NRK was found to interact with SAMHD1 protein and promote phosphorylation at SAMHD1 Thr592 site by Co-IP and Western blot assay．@*Conclusion @#Phosphorylation of the Thr592 site contributes to the loss of SAMHD1 's ability to inhibit gastric cancer cell proliferation，which is reversed by Palbociclib．NRK interacts with SAMHD1 protein，promoting phosphorylation of the SAMHD1 Thr592 site.

Analysis of risk factors on vascular invasion in patients with early gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the risk factors of vascular invasion in patients with early gastric cancer (EGC), and to investigate the influence of vascular invasion on the prognosis of EGC patients.</p><p><b>METHODS</b>From January 2014 to December 2015, 449 EGC patients underwent curative gastrectomy at the First Affiliated Hospital of Anhui Medical University, of whom 27 cases (6.0%) developed vascular invasion. Clinicopathological and follow-up data of EGC cases were analyzed retrospectively. The association between clinicopathological features and vascular invasion was analyzed by using the Chi-square test or Fisher exact test, and the independent risk factors influencing vascular invasion were identified with logistic regression. The influence of vascular invasion on overall survival was investigated with Kaplan-Meier curve. This study was approved by Ethics Committee of The First Affiliated Hospital of Anhui Medical University (No. 2018-03-12).</p><p><b>RESULTS</b>Of 449 EGC patients, 325 were males and 124 were females (ratio 2.6:1.0) with the mean age of (60.8±10.5) (27 to 87) years; 228 were diagnosed as T1a stage and 221 were diagnosed as T1b. Univariate analysis showed that incidence of vascular invasion in EGC patients with ulceration or scar was 8.4%(18/225), which was higher than 3.8%(9/234) in those without ulceration, and the difference was statistically significant (χ²=4.061, P=0.044). The incidence of vascular invasion in patients with low differentiated tumor was 8.8% (20/226), which was significantly higher than 3.1%(7/223) in those with middle-high differentiated tumor(χ²= 8.363, P=0.012). The incidence of vascular invasion in patients staging T1b was 10.9% (24/221), which was significantly higher than 1.3% (3/228) in those staging T1a (P=0.000); The incidence of vascular invasion in patients with lymph node metastasis was 27.3% (15/55), which was significantly higher than 3.0%(12/394) in those without lymph node metastasis (χ²=50.122, P=0.000). However, there were no significant associations of vascular invasion with gender, age, surgical type, multiple tumor, tumor deposit, tumor location and tumor size (all P > 0.05). Multivariate analysis showed that T1b stage (RR=4.653, 95%CI:1.293-16.747, P=0.019) and lymph node metastasis(RR=7.302, 95%CI: 3.063-17.408, P=0.000) were independent risk factors for vascular invasion in EGC patients. Among 449 EGC patients, 444 received complete follow-up(98.9%), including 26 cases with vascular invasion and 418 cases without vascular invasion. The overall survival in vascular invasion group was significantly lower than that in non-vascular invasion group (χ²=60.463, P=0.000). Besides, 198 EGC patients gained follow-up for 3 years, and the 3-year survival rates of 11 vascular invasion cases and 187 non-vascular invasion cases were 54.5% and 96.8% respectively.</p><p><b>CONCLUSIONS</b>The risk of vascular invasion is higher in EGC patients with lymph node metastasis and tumor infiltrating the submucosa. The prognosis of EGC patients with vascular invasion is poor.</p>

Stratifying risk and establishing predictive risk-scoring model for lymph-node metastasis in early gastric cancer / 中华普通外科杂志

Objective To explore the independent risk factors of lymph-node metastasis (LNM) in patients with early gastric cancer (EGC),and establish a risk-prediction model based on LNM.Method 962 early gastric cancer patients undergoing curative radical gastrectomy in the First Hospital of Anhui Medical University from July 2011 to April 2016 were enrolled in this study.The relationships between different clinicopathologic characteristics and LNM were analyzed by Chi-square test or Fisher exact probability,and the independent risk factors were determined using Logistic regression analysis.Moreover,LNM risk was stratified and a risk-predicting model was established on the basis of the identified independent risk factors for LNM.Further,the risk-predicting model was validated using 962 EGC cases.The discriminatory accuracy of risk-predicting model was measured by area under ROC curve (ROC-AUC).Results Mucosal differentiated cancer ≤2 cm,irrespective of the existence of an ulcer,had low LNM rates (LNMR ＜ 3.0％).Univariate and multivariate analysis revealed that female EGC patients with submucosal,undifferentiated,vessel invasion and tumor size ＞ 2 cm were independent risk factors of LNM for EGC patients,and relative risks were 1.893,3.173,1.956,1.922 and 9.027 respectively (P ＜ 0.05).ROCAUC of risk-predicting model was 0.768 (P ＜ 0.01),which showed high diagnostic accuracy and sensitivity.Conclusion Female EGC patients with submucosal undifferentiated carcinomas measuring ＞ 2 cm with vessel invasion have higher risk of LNM.

Analysis of risk factors influencing the overall survival and establishment of nomogram predicting model in patients with rectal cancer at T1 and T2 stage / 安徽医科大学学报

Objective @#To explore the independent risk factors affecting the prognosis，and to construct a nomogram model predicting overall of patients with rectal cancer at T1 and T2 stage．@*Methods @#Retrospective analysis was made on the data of 353 patients diagnosed as rectal cancer，who received the radical rectal resection．The collect- ed data were as follows : age，body mass index (BMI) ，carcinoembryonic antigen ( CEA) ，tumor size，histological type，T stage，N stage，tumor location and number of lymph nodes detected，which were used to perform Kaplan- Meier curve and Log-rank test for univariate analysis and Cox regression for multivariate analysis．The nomogram model was established to predict the overall survival of patients. @*Results @#Age≥60 years，Mucinous adenocarcino- ma，poorly differentiation ，T2 stage ，lymph node metastasis ，BMI ≥25 kg / m2 ，CEA ≥5 μg / L and number of lymph nodes detected ＜12 were associated with overall survival of patients with rectal cancer at T1 and T2 stage (all P＜0. 05) ．Cox regression showed that age≥60 years，T2 stage，mucinous adenocarcinoma，lymph node me- tastasis，CEA≥5 μg / L，BMI ≥25 kg / m2 and lymph node detection number ＜12 were independent risk factors. Based on the above independent risk factors，the nomogram model was constructed，and the predicted curve was in good agreement with the actual survival curve ( C-index = 0. 779) ．@*Conclusion @#Age≥60 years，T2 stage，mucin- ous adenocarcinoma，lymph node metastasis，CEA≥5 μg / L，BMI≥25 kg / m2 and the number of lymph nodes de- tected ＜12 are independent risk factors ，and the nomogram established in this study can effectively predict the prognosis of patients with rectal cancer at T1 and T2 stage.