Luteolin blocks the ROS/PI3K/AKT pathway to inhibit mesothelial-mesenchymal transition and reduce abdominal adhesions.

BACKGROUND: Postoperative abdominal adhesion (PAA) is a common postoperative complication. Clinically, various methods have been used to prevent the occurrence of PAA, such as drugs and physiotherapy; however, no satisfactory results have been obtained. Luteolin (LUT) is a natural flavonoid that reduces inflammation and acts as an antioxidant. This research aimed to examine the impact and mechanism of LUT in reducing PAA. METHODS: C57/BL6 mice were used in vivo experiments. PAA model was established using a brush friction method. Visual scoring and hematoxylin and eosin staining were used to score the severity of adhesions. Network pharmacology was used to infer potential targets and core pathways of LUT. Hydrogen peroxide (H2O2) was used to induce oxidative stress in vitro, while the reactive oxygen species (ROS) assay kit was used to evaluate oxidative stress levels. Western blotting, cell immunofluorescence, and multiple immunofluorescence assays were used to detect α-SMA, vimentin, E-cadherin, collagen I, or AKT phosphorylation level. Scratch assay was used to detect cell migration. RESULTS: LUT reduced the degree of PAA in mice. It attenuated H2O2-induced ROS production and reversed mesothelial-mesenchymal transition (MMT) in HMrSV5 cells. Network pharmacology analysis showed that LUT likely exerted anti-adhesion activity by regulating the PI3K-Akt signaling pathway. Phosphorylated Akt levels were significantly reduced in LUT-treated HMrSV5 cells. LUT also significantly reduced the expression of vimentin and collagen I in adherent tissues and upregulated E-cadherin expression. CONCLUSION: LUT blocks the ROS/PI3K/AKT pathway, thereby inhibiting MMT and reducing PAA. To this end, LUT has potential in PAA therapy.

Mixed reality in primary retroperitoneal tumour surgery: Evaluation of preoperative and intraoperative application value.

OBJECTIVE: To evaluate the feasibility and application value of mixed reality technology (MR) in Primary retroperitoneal tumour (PRT) surgery. METHODS: From 276 patients who underwent PRT resection at the First Affiliated Hospital of Xi'an Jiaotong University, we screened 46 patients who underwent MR-assisted retroperitoneal tumour resection and 46 patients who underwent tumour resection without MR assistance. The intraoperative and postoperative recovery of the patients in both groups were compared, and the reliability and validity of the application of MR were further examined using the Likert scale. RESULTS: There was a significant difference in the mean intraoperative bleeding volume between the two groups, but it was reduced in the MR group. The results of the Likert scale showed higher scores in the MR group than non-MR group. CONCLUSIONS: MR can be used to assist PRT resection and has great potential to improve the rate of complete retroperitoneal tumour resection.

SIRT1 mediated gastric cancer progression under glucose deprivation through the FoxO1-Rab7-autophagy axis.

Purpose: Silent mating type information regulator 2 homolog 1 (SIRT1) and autophagy have a two-way action (promoting cell death or survival) on the progression and treatment of gastric cancer (GC) under different conditions or environments. This study aimed to investigate the effects and underlying mechanism of SIRT1 on autophagy and the malignant biological behavior of GC cells under conditions of glucose deprivation (GD). Materials and methods: Human immortalized gastric mucosal cell GES-1 and GC cell lines SGC-7901, BGC-823, MKN-45 and MKN-28 were utilized. A sugar-free or low-sugar (glucose concentration, 2.5 mmol/L) DMEM medium was used to simulate GD. Additionally, CCK8, colony formation, scratches, transwell, siRNA interference, mRFP-GFP-LC3 adenovirus infection, flow cytometry and western blot assays were performed to investigate the role of SIRT1 in autophagy and malignant biological behaviors (proliferation, migration, invasion, apoptosis and cell cycle) of GC under GD and the underlying mechanism. Results: SGC-7901 cells had the longest tolerance time to GD culture conditions, which had the highest expression of SIRT1 protein and the level of basal autophagy. With the extension of GD time, the autophagy activity in SGC-7901 cells also increased. Under GD conditions, we found a close relationship between SIRT1, FoxO1 and Rab7 in SGC-7901 cells. SIRT1 regulated the activity of FoxO1 and upregulated the expression of Rab7 through deacetylation, which ultimately affected autophagy in GC cells. In addition, changing the expression of FoxO1 provided feedback on the expression of SIRT1 in the cell. Reducing SIRT1, FoxO1 or Rab7 expression significantly inhibited the autophagy levels of GC cells under GD conditions, decreased the tolerance of GC cells to GD, enhanced the inhibition of GD in GC cell proliferation, migration and invasion and increased apoptosis induced by GD. Conclusion: The SIRT1-FoxO1-Rab7 pathway is crucial for the autophagy and malignant biological behaviors of GC cells under GD conditions, which could be a new target for the treatment of GC.

The role of [99mTc]Tc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience.

BACKGROUND: Recently, PET/CT imaging with radiolabelled FAP inhibitors (FAPIs) has been widely evaluated in diverse diseases. However, rare report has been published using SPECT/CT, a more available imaging method, with [99mTc]Tc-labelled FAPI. In this study, we evaluated the potential effect of [99mTc]Tc-HFAPi in clinical analysis for digestive system tumours. METHODS: This is a single-centre prospective diagnostic efficiency study (Ethic approved No.: XJTU1AF2021LSK-021 of the First Affiliated Hospital of Xi'an Jiaotong University and ChiCTR2100048093 of the Chinese Clinical Trial Register). Forty patients with suspected or confirmed digestive system tumours underwent [99mTc]Tc-HFAPi SPECT/CT between January and June 2021. For dynamic biodistribution and dosimetry estimation, whole-body planar scintigraphy was performed at 10, 30, 90, 150, and 240 min post-injection in four representative patients. Optimal acquisition time was considered in all the patients at 60-90 min post-injection, then quantified or semi-quantified using SUVmax and T/B ratio was done. The diagnostic performance of [99mTc]Tc-HFAPi was calculated and compared with those of contrast-enhanced CT (ceCT) using McNemar test, and the changes of tumour stage and oncologic management were recorded. RESULTS: Physiological distribution of [99mTc]Tc-HFAPi was observed in the liver, pancreas, gallbladder, and to a lesser extent in the kidneys, spleen and thyroid. Totally, 40 patients with 115 lesions were analysed. The diagnostic sensitivity of [99mTc]Tc-HFAPi for non-operative primary lesions was similar to that of ceCT (94.29% [33/35] vs 100% [35/35], respectively; P = 0.5); in local relapse detection, [99mTc]Tc-HFAPi was successfully detected in 100% (n = 3) of patients. In the diagnosis of suspected metastatic lesions, [99mTc]Tc-HFAPi exhibited higher sensitivity (89.66% [26/29] vs 68.97% [20/29], respectively, P = 0.03) and specificity (97.9% [47/48] vs 85.4% [41/48], respectively, P = 0.03) than ceCT, especially with 100% (24/24) specificity in the diagnosis of liver metastases, resulting in 20.0% (8/40) changes in TNM stage and 15.0% (6/40) changes in oncologic management. CONCLUSION: [99mTc]Tc-HFAPi demonstrates a greater diagnostic efficiency than ceCT in the detection of distant metastasis, especially in identifying liver metastases.

CircRNA-ABCB10 promotes gastric cancer progression by sponging miR-1915-3p to upregulate RaC1.

BACKGROUND: Gastric cancer (GC) is a common malignant tumor of the digestive system. Increasing reports have demonstrated the crucial roles of circRNAs in tumorigenesis and progression of GC. METHODS: The relative expression of circ-ABCB10 in GC tissues and cell lines was detected by qRT-PCR. A series of in vitro assays and a xenograft model in vivo were applied to explore the function of circ-ABCB10 in GC cells. RESULTS: Circ-ABCB10 expression was upregulated in GC tissues and cell lines and positively correlated with poor survival of GC patients. Circ-ABCB10 downregulation decreased cell viability, inhibited cell growth, invasion, and migration, while promoted cell apoptosis of GC cell lines SGC-7901 and MKN-48. Circ-ABCB10 could upregulate Rac1 expression by directly sponging miR-1915-3p. Rescue experiments revealed that miR-1915-3p inhibitor obviously reversed the inhibitory effect of si-circ-ABCB10, and Rac1 overexpression obviously reversed the inhibitory effect of miR-1915-3p mimics on cell growth, invasion, migration, apoptosis, and cell cycle progression. Moreover, si-circ-ABCB10 effectively inhibited tumor growth in a xenograft model. CONCLUSIONS: Our study revealed that circ-ABCB10 promoted GC progression via targeting the miR-1915-3p/Rac1 axis, and circ-ABCB10 might be a potential target for GC diagnosis and treatment.

A Nomogram Model Involving Preoperative Fibrinogen and Prognostic Nutritional Index Score for Predicting Postoperative Outcome in Patients with Gastric Cancer.

BACKGROUND: Inflammation and nutrition play vital roles in the development of gastric cancer (GC). We combined the preoperative fibrinogen with prognostic nutritional index (PNI) to create a novel scoring system named as the fibrinogen and prognostic nutritional index (FPNI) score and establish a more effective model. PATIENTS AND METHODS: A total of 689 patients with gastric adenocarcinoma who underwent gastrectomy from January 2012 to December 2016 were reviewed. We measured correlations between FPNI score and clinicopathological variables and overall survival (OS). A nomogram predicting OS was constructed. Its predictive performance was verified using the concordance index, calibration curves, receiver operating characteristic curves, decision curve analysis and time-dependent receiver operating characteristic analysis. RESULTS: We observed that the FPNI score was an independent predictor of OS in patients with gastric cancer (P < 0.05). A high FPNI score was significantly related to older age at surgery, tumor size ≥4.6 cm, high ASA score, advanced TNM stage and poor outcome (both P < 0.05). And the FPNI score remained an independent indicator at various TNM stages (P < 0.05). Ultimately, the nomogram based on FPNI score, age, tumor size, histological grade and TNM stage showed a better predictive ability than TNM alone. CONCLUSION: The preoperative FPNI score is a novel, simple, and effective predictor of OS in patients with GC. Furthermore, the nomogram involving FPNI score will help clinicians to optimize individualized treatment plans.

A nomogram combining plasma fibrinogen and systemic immune­inflammation index predicts survival in patients with resectable gastric cancer.

Hyperfibrinogenemia and cancer-associated systemic inflammatory response are strongly associated with cancer progression and prognosis. We aimed to develop a novel prognostic score (F-SII score) on the basis of preoperative fibrinogen (F) and systemic immunoinflammatory index (SII), and evaluate its predictive value in patients with resectable gastric cancer (GC). Patients diagnosed with GC between January 2012 and December 2016 were reviewed. The F-SII score was 2 for patients with a high fibrinogen level (≥ 3.37 g/L) and a high SII (≥ 372.8), whereas that for patients with one or neither was 1 or 0, respectively. A high F-SII score was significantly associated with older patient age, a high ASA score, large tumor size, large proportion of perineural invasion, and late TNM stage. Multivariate analysis indicated that the F-SII score, histological grade, and TNM stage were independent factors for overall survival (OS). The Harrell's concordance index (C-index) of a nomogram based on the F-SII score and several clinicopathological manifestations was 0.72, which showed a better predictive ability for OS than the TNM stage alone (0.68). In conclusion, preoperative F-SII may serve as a useful predictive factor for OS and refine outcome prediction for patients with resectable GC combined with traditional clinicopathological analysis.

Exosomal MiR-744 Inhibits Proliferation and Sorafenib Chemoresistance in Hepatocellular Carcinoma by Targeting PAX2.

BACKGROUND Hepatocellular carcinoma (HCC) is a commonly occurring liver malignancy. Its prognosis remains unsatisfactory. Accumulating evidence has revealed that exosomal microRNAs (miRNAs) act as biomarkers and play crucial roles in the advancement of HCC. The current study explored the biological role and fundamental mechanism of exosomal miR-744 in HCC. MATERIAL AND METHODS The serum exosomes of HCC patients were isolated by differential ultracentrifugation. MiR-744 expression in HCC tissues, cell lines and serum exosomes were detected by quantitative real-time polymerase chain reaction (qRT-PCR). EdU (5-ethynyl-2'-deoxyuridine) assay and Cell Counting Kit-8 (CCK-8) assay were conducted to show the impacts of miR-744 or exosomal miR-744 on proliferation and sorafenib resistance in HepG2 cells. The target of miR-744 was ascertained by regulating the level of miR-744 in HepG2 cells. RESULTS MiR-744 is downregulated in HCC tissues and cell lines as well as in exosomes derived from patient serum and HepG2 cells. Additionally, downregulated miR-744 promotes HepG2 cell proliferation and inhibits the chemosensitivity of HepG2 cells to sorafenib. PAX2 was identified as the functional target of miR-744. Interestingly, miR-744 is decreased in exosomes derived from sorafenib-resistant HepG2 cells. Furthermore, when treated with the miR-744-enriched exosomes, the proliferation of HepG2 cells was significantly suppressed, and the sorafenib resistance was reduced. CONCLUSIONS MiR-744 has an imperative role in the propagation and chemoresistance of HCC. Serum exosomal miR-744 might act as a biomarker of HCC, and exosomal miR-744 might offer an innovative strategy for HCC treatment.

Upregulation of microRNA­300 induces the proliferation of liver cancer by downregulating transcription factor FOXO1.

In the present study, we investigated whether miRNA­300 (miR­300) is an oncogene in human liver cancer and sought to determine the mechanism underlying its activity. We also investigated the effect of miRNA­300 on the growth in liver cancer. To identify its target molecule, we performed luciferase assays. The downstream signaling pathway was detected by immunohistochemical (IHC) analysis in human HCC tissues, and the protein levels of AKT, 4E­BP1, S6K1, SNAIL and MMP2 were determined using western blotting. miR­300 levels were higher in patients with high­stage HCC, and miR­300 promoted cell growth both in vitro and in vivo. miRNA­300 inhibited the luciferase activity of FOXO1 by targeting its 3'­untranslated region (UTR), and overexpression of miR­300 upregulated the protein levels of phospho­AKT, phospho­4E­BP1, phospho­S6K1, SNAIL and MMP2. These data revealed that miRNA­300 functions as an oncogene in liver cancer by inhibiting FOXO1 and interacting with the AKT/mTOR signaling pathway.

Long non-coding RNA FOXD2-AS1 plays an oncogenic role in hepatocellular carcinoma by targeting miR­206.

Recently, long non-coding RNA (lncRNA) FOXD2 adjacent opposite strand RNA 1 (FOXD2-AS1) has been recognized to function as an oncogene in several human tumors, and FOXD2­AS1 dysregulation has been closely associated with carcinogenesis and tumor progression. Nevertheless, the correlation between the aberrant expression of FOXD2­AS1 and the prognosis of hepatocellular carcinoma (HCC) has not yet been elucidated. In the present study, FOXD2­AS1 was found to be overexpressed in HCC tissues, and FOXD2­AS1 overexpression resulted in significantly shortened patient survival. FOXD2­AS1 overexpression enhanced the viability and metastasis of HCC cells in vitro and in vivo, as revealed by MTT, wound healing and cell migration assays. In addition, mechanistic studies revealed that FOXD2­AS1 upregulated the expression of the miR­206 target gene annexin A2 (ANXA2) by acting as a miR­206 sponge. In summary, FOXD2­AS1 was concluded to function as an oncogene in HCC and to upregulate ANXA2 expression in part by 'sponging' miR­206.

The role of propranolol as a radiosensitizer in gastric cancer treatment.

PURPOSE: The National Comprehensive Cancer Network guidelines indicate that radiotherapy in gastric cancer shows limited effectiveness at reducing the growth of gastric cancer. Therefore, enhancing the sensitivity and effect of radiotherapy with propranolol, a ß-adrenoceptor antagonist, could reduce tumor growth. The role of propranolol as a radiosensitizer has not been adequately studied; therefore, the purpose of the present study is to evaluate the effect of propranolol as a radiosensitizer against gastric cancer in vivo. METHODS: Sixty-four male nude mice bearing tumor xenografts were randomly divided into four groups. Cell culture was performed using the human gastric adenocarcinoma cell line SGC-7901. Mice with tumor xenografts were treated with propranolol, isoproterenol, and radiation. The data for tumor weight and volume were obtained for statistical analyses. Furthermore, the expression levels of COX-2, NF-κB, VEGF, and EGFR were examined using immunohistochemical techniques and Western blotting. RESULTS: The growth in the volume and weight of the tumor was lower in mouse models treated with propranolol and radiation therapy compared to the other groups. Decreased expression of NF-κB was also observed in treatment groups where both propranolol and radiation were used, leading to the reduction of COX-2, EGFR, and VEGF expression compared to that in the other groups. CONCLUSION: The present study indicated that propranolol potentiates the antitumor effects of radiotherapy in gastric cancer by inhibiting NF-κB expression and its downstream genes: VEGF, EGFR, and COX-2.

Gastrointestinal stromal tumors: Fibrinogen levels are associated with prognosis of patients as blood-based biomarker.

Improved prediction of prognosis for primary gastrointestinal stromal tumors (GISTs) after curative resection is an important goal in clinical practice. Coagulation factor of fibrinogen may inform prognosis of tumor patients as blood-based biomarker. Here, we aimed to analyze the prognostic value of fibrinogen levels in patients with GIST and to explore potential threshold of fibrinogen on postoperative clinical outcome.A retrospective study was performed including data from 91 patients with newly diagnosed GISTs who underwent curative resection. Patients were followed-up for a median period of 2 years. Cox regression and competing risk analysis were applied to study the association between fibrinogen and risk of death or recurrence. Smoothing plot and threshold effect analysis were applied to learn the relationship further and explore potential threshold.High levels of fibrinogen are associated with decreased overall survival (OS) and recurrence free survival (RFS) in patients with GISTs. We discovered a nonlinear relationship between levels of fibrinogen and the risk of death or recurrence. Further, we detected a threshold for fibrinogen (3.7 g/L) on the prognosis of GISTs patients. When fibrinogen was above the inflection point, the increase in fibrinogen levels was strongly associated with increase in the risk of death or recurrence.Elevated fibrinogen can serve as an independent prognostic biomarker for a worse clinical outcome in GIST patients.

Laparoscopic Versus Open Resection of Gastric Gastrointestinal Stromal Tumors Larger Than 5 cm: A Single-Center, Retrospective Study.

BACKGROUND: The technical feasibility and oncological safety of laparoscopic surgery for gastric gastrointestinal stromal tumors (GISTs) larger than 5 cm has not been adequately studied. Therefore, we performed this retrospective study to investigate the clinical outcomes of gastric GIST patients treated with laparoscopic surgery compared with those who underwent open surgery. METHODS: We retrospectively evaluated the outcomes of 48 consecutive patients who underwent gastric resection for gastric GISTs larger than 5 cm. The patients were divided into 2 groups based on the surgery performed: the laparoscopic resection group (LAPG) and the open resection group (OG). We assessed all available patient data, including baseline information, tumor characteristics, surgical outcomes, pathological results, postoperative complications, and long-term patient survival. RESULTS: The 2 groups had similar baseline data. No differences were found in tumor size, location, mitotic count, and risk grade according to Fletcher's risk classification. The LAPG was superior to the OG in blood loss, time to first flatus, time to oral intake, and length of postoperative hospital stay. Perioperative complications, recurrence rate, and long-term survival, however, did not differ significantly between the groups. The mean operation time in the LAPG was 28 minutes longer than that in the OG. CONCLUSIONS: In patients with primary gastric GISTs larger than 5 cm, laparoscopic resection is a technically feasible and oncologically safe surgery when performed by experienced surgeons.

MicroRNA-125b promotes invasion and metastasis of gastric cancer by targeting STARD13 and NEU1.

MicroRNAs have been documented playing key roles in cancer development and progression. Here, we investigate the role of miR-125b in gastric cancer metastasis. We found that the expression of miR-125b was up-regulated in gastric cancer tissue specimens compared with their corresponding nontumorous tissues, and the up-regulated miR-125b level was significantly associated with TNM stage and lymph node-metastasis. Overexpression of miR-125b promoted gastric cancer cell migration and invasion in vitro and metastasis in vivo. STARD13 and NEU1 were identified as direct target genes of miR-125b by luciferase assays, and they were involved in the cell migration and invasion regulated by miR-125b in gastric cancer. Taken together, miR-125b functions as an oncogene in gastric cancer and represents a new potential therapeutic target for gastric cancer.

Recovery of Urinary Functions After Laparoscopic Total Mesorectal Excision for T4 Rectal Cancer.

BACKGROUND: Postoperative urinary dysfunction after total mesorectal excision (TME) is lessened by preservation of the autonomic nerves, but in T4 rectal tumors such injury often cannot be prevented. This retrospective study evaluated the recovery of urinary function of patients with injury to a single pelvic autonomic nerve subsequent to laparoscopic TME, relative to patients without nerve damage. METHODS: Patients with T4 rectal cancer who underwent laparoscopic TME were divided according to the presence of a single pelvic autonomic nerve injury (37 cases) or no injury to autonomic nerves (54 cases; control). Urinary function was evaluated before surgery and at 1 and 6 months after surgery based on catheter indwelling time, urodynamics, International Prostate Symptom Score (IPSS; men only), and Urogenital Distress Inventory (UDI-6) score (women). RESULTS: One month after surgery in the injured and control groups, the postoperative catheter indwelling time was 6.2 ± 2.0 and 1.9 ± 1.2 days, respectively; the maximal urinary flow rates were 16.6 ± 5.8 and 19.7 ± 5.5 mL/s; the voided volumes were 181.6 ± 65.9 and 211.7 ± 63.2 mL; and the residual volumes were 15.0 ± 8.5 and 10.8 ± 8.0 mL. However, at the 6-month follow-up, all urodynamic parameters of the two groups were statistically similar and indicated recovery, and the IPSS and UDI-6 scores were also not statistically different. CONCLUSION: Damage to a single pelvic autonomic nerve during laparoscopic TME does not lead to long-term urinary dysfunction.

HOTTIP and HOXA13 are oncogenes associated with gastric cancer progression.

A long non-coding RNA named HOTTIP (HOXA transcript at the distal tip) coordinates the activation of various 5' HOXA genes which encode master regulators of development through targeting the WDR5/MLL complex. HOTTIP acts as an oncogene in several types of cancers, whereas its biological function in gastric cancer has never been studied. In the present study, we investigated the role of HOTTIP in gastric cancer. We found that HOTTIP was upregulated in gastric cancer cell lines. Knockdown of HOTTIP in gastric cancer cells inhibited cell proliferation, migration and invasion. Moreover, downregulation of HOTTIP led to decreased expression of homeobox protein Hox-A13 (HOXA13) in gastric cancer cell lines. HOXA13 was involved in HOTTIP­induced malignant phenotypes of gastric cancer cells. Our data showed that the levels of HOTTIP and HOXA13 were both markedly upregulated in gastric cancer tissues compared with their counterparts in non-tumorous tissues. Furthermore, the expression levels of HOTTIP and HOXA13 were both higher in gastric cancer which was poorly differentiated, at advanced TNM stages and exhibited lymph node-metastasis. Spearman analyses indicated that HOTTIP and HOXA13 had a highly positive correlation both in non-tumor mucosae and cancer lesions. Collectively, these findings suggest that HOTTIP and HOXA13 play important roles in gastric cancer progression and provide a new insight into therapeutic treatment for the disease.

The Prognostic Role of SIRT1-Autophagy Axis in Gastric Cancer.

Aim. Sirtuin 1 (SIRT1) can induce autophagy through deacetylation of Beclin-1 and other autophagy mediators. However, the relationship between SIRT1 and autophagy in GC has not been defined. Therefore, the aim of this study was to confirm the prognostic value of SIRT1 and Beclin-1 and their relationship in GC patients. Methods. Transmission electron microscopy (TEM) was performed to examine the autophagy in GC patients. Immunohistochemistry was used to examine the expression of SIRT1, Beclin-1 in GC, and adjacent nonneoplastic mucosa. Results. In 7 out of 8 GC patients' samples examined by TEM, more autophagic vesicles were observed in GC tissues compared to adjacent nonneoplastic mucosa tissue. A positive correlation between SIRT1 and Beclin-1 expression was observed. Furthermore, Beclin-1 or SIRT1 expression alone or their combined expression were significantly correlated with advanced clinicopathological parameters. High Beclin-1 and SIRT1 expression alone and their combined high expression predicted shorter overall survival and relapse-free survival. Both high Beclin-1 and SIRT1 expressions were independent prognostic factors for poor survival of GC. Conclusions. Based on our results we can conclude that SIRT1 and Beclin-1 expression alone or in combination can be used as prognostic indicator and may represent new therapeutic targets in GC.

ß-elemene enhances the radiosensitivity of gastric cancer cells by inhibiting Pak1 activation.

AIM: To explore the potential of ß-elemene as a radiosensitizer for gastric cancer cells and the underlying mechanisms. METHODS: SGC7901, MKN45, MKN28, N87, and AGS human gastric cancer cell lines were used to screen for radioresistant gastric cancer cell lines. A 3-(4,5-dimeth-ylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay was used to determine the effects of ß-elemene and IPA-3 on cell viability in MKN45 and SGC7901 gastric cancer cell lines. A clonogenic survival assay and annexin V-FITC/PI apoptosis detection assay were used to evaluate cellular radiosensitivity and radiation-induced cell death, respectively. A proteomic method, isobaric tags for relative and absolute quantitation (iTRAQ), was employed to screen the proteins regulated by ß-elemene pretreatment prior to ionizing radiation (IR) in SGC7901 gastric cancer cell line. IPA-3 was used as a specific small molecule inhibitor of p21-activated protein kinase 1 (Pak1) to target Pak1 signaling. Protein levels of PAK1IP1 (p21-activated protein kinase-interacting protein 1), total Pak1 (t-Pak1), phospho-Pak1 (T423), phospho-ERK1/2 (Thr202/Tyr204), and cleaved caspase-3 (17 kDa) were assessed by western blotting. RESULTS: MKN45 and SGC7901 gastric cancer cell lines were relatively more resistant to IR. ß-elemene pretreatment decreased clonogenic survival following IR in MKN45 and SGC7901 gastric cancer cell lines. Additionally, ß-elemene pretreatment prior to IR increased radiation-induced cell death compared with IR alone in MKN45 (10.4% ± 0.9% vs 34.8% ± 2.8%, P < 0.05) and SGC7901 (11.6% ± 0.9% vs 46.7% ± 5.2%, P < 0.05) human gastric cancer cell lines, respectively, consistent with the level of cleaved caspase-3 (17 kDa). Through iTRAQ analysis and western blot validation, we found that ß-elemene upregulated PAK1IP1 and downregulated phospho-Pak1 (T423) and phospho-ERK1/2 in SGC7901 gastric cancer cells. IR increased the level of phospho-Pak1 (T423). Pretreatment with ß-elemene decreased radiation-induced Pak1 and ERK1/2 phosphorylation. Inhibition of Pak1 using IPA-3 decreased clonogenic survival following IR. In addition, IPA-3 increased radiation-induced cell death in MKN45 (13.4% ± 0.3% vs 26.6% ± 1.0%, P < 0.05) and SGC7901 (16.0% ± 0.6% vs 37.3% ± 1.7%, P < 0.05) gastric cancer cell lines, respectively, consistent with the level of cleaved caspase-3 (17 kDa). Western blotting showed that IPA-3 decreased radiation-induced Pak1 and ERK1/2 phosphorylation. CONCLUSION: This is the first demonstration that ß-elemene enhances radiosensitivity of gastric cancer cells, and that the mechanism involves inhibition of Pak1 signaling.

[Effects of ß-elemene on proliferation and apoptosis of SGC7901 gastric cancer cells in vitro and the underlying mechanisms].

OBJECTIVE: To investigate the effects of ß-elemene in suppressing the proliferation and apoptosis of SGC7901 gastric cancer cells in vitro and explore the underlying mechanisms. METHODS: Using MTT assay, flow cytometry, and clonogenic survival assay, we assessed the effects of ß-elemene on the viability, apoptosis, cell cycle distribution, and clonogenic survival of gastric cancer SGC7901 cells and gastric mucosal epithelial GES-1 cells. Western blotting was employed to determine the changes in the protein expression profiles in SGC7901 cells in response to ß-elemene treatment. RESULTS: ß-elemene significantly suppressed the cell viability and increased the apoptosis of SGC7901 cells, and these effects were less obvious in GES-1 cells. ß-elemene decreased clonogenic survival of SGC7901 cells, increased the proportion of G2/M phase cells, decreased the expression of Bcl-2, and increased the expression of Bax and cleaved caspase-3. ß-elemene did not obviously affect the expression of total p21-activated protein kinase 1 (Pak1) but decreased the level of phospho-Pak1 (Thr423) and phospho-ERK1/2 (Thr202/Tyr204) in SGC7901 cells. CONCLUSION: ß-elemene inhibits the proliferation and induces apoptosis of gastric cancer cells possibly by inhibiting Pak1/ERK signaling and regulating apoptosis-associated proteins such as Bcl-2 and Bax.

SIRT1 is a regulator of autophagy: Implications in gastric cancer progression and treatment.

Silent mating type information regulation 1 (SIRT1) is implicated in tumorigenesis through its effect on autophagy. In gastric cancer (GC), SIRT1 is a marker for prognosis and is involved in cell invasion, proliferation, epithelial-mesenchymal transition (EMT) and drug resistance. Autophagy can function as a cell-survival mechanism or lead to cell death during the genesis and treatment of GC. This functionality is determined by factors including the stage of the tumor, cellular context and stress levels. Interestingly, SIRT1 can regulate autophagy through the deacetylation of autophagy-related genes (ATGs) and mediators of autophagy. Taken together, these findings support the need for continued research efforts to understand the mechanisms mediating the development of gastric cancer and unveil new strategies to eradicate this disease.