[Micrometastasis in Gastric Cancer]

Knockdown of hsa_circ_0091994 constrains gastric cancer progression by suppressing the miR-324-5p/HMGA1 axis

CircRNAs have emerged as potential therapeutic targets for diseases such as gastric cancer (GC). We identified highly dysregulated circRNAs in GC tissue and further explored their potential mechanisms in the progression of GC. Hsa_circ_0091994 (cicrRNA_105040) was identified as a highly upregulated circRNA in GC tissues, whose host gene is negatively associated with the overall survival of patients. Using cell counting kit-8 and Annexin V assays, we observed that hsa_circ_0091994 knockdown inhibited the viability of AGS and HGC-27 cells by inducing apoptosis. Scratch wound healing assays showed that hsa_circ_0091994 knockdown also inhibited GC cell healing. Bioinformatics analysis and a luciferase assays revealed that hsa_circ_0091994 knockdown inhibits GC progression by suppressing miR-324-5p and HMGA1 expression. The antitumor effect of hsa_circ_0091994 knockdown was confirmed in vivo using a mouse xenograft model. Hsa_circ_0091994 knockdown inhibited the progression of GC by inhibiting the miR-324-5p/HMGA1 axis.

Luteolin and cancer metastasis suppression: focus on the role of epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is a physiological process that assumes a primary role in the induction of cancer metastasis. This results in increased cell renewal, and resistance to cell death and therapies. EMT, therefore, represents an effective strategy for regulating cancerous cell activity. A need for efficacy and low cytotoxicity epithelial to mesenchymal transition modifying drugs has led to the investigational testing of the efficacy of plethora of different groups of phytonutrients. Luteolin is a natural flavonoid inhibits the growth of cancer cells by various mechanisms, such as the stimulation of cancer cell apoptosis, cell cycle arrest, inhibition of cell replication, tumor growth, improvement of drug resistance, prevention of cancer cell intrusiveness and metastasis. This review article focuses on the anti-cancer and anti-metastatic potential of luteolin targeting various transcription factors, markers and signaling pathways associated with the repression of epithelial to mesenchymal transition.

Disentangling the obesity paradox in upper gastrointestinal cancers: Weight loss matters more than body mass index

OBJECTIVES

The obesity paradox, whereby obesity appears to confer protection against cancer-related mortality, remains controversial. This has not yet been evaluated in upper gastrointestinal cancers.

DESIGNS

We identified esophageal, cardia, and non-cardia gastric adenocarcinomas in the Veterans Health Administration between 2006-2016. Multivariable Cox proportional hazard models evaluate the impact of BMI at- and prior to- cancer diagnosis on mortality, adjusting for demographics, clinical characteristics, weight loss, and clinical stage (early: T1B/2N0; locally advanced: ≥T2N+).

RESULTS

We identify 1308 patients: 99 % male, median 66 years. In early disease, relative to BMI 30, BMI 18 and 20 at diagnosis had increased risk of death (HR 1.83, 95 %CI: 1.38-2.44 and HR 1.50, 95 %CI: 1.20-1.87, respectively, p < 0.0001). Patients with BMI > 30 did not. In locally advanced disease, at diagnosis BMI 18 (HR 1.58, 95 %CI: 1.0001-1.48, p = 0.05), BMI 20 (HR 1.46, 95 %CI: 1.01-2.09, p = 0.04), and BMI 25 (HR 1.20, 95 %CI: 1.04-1.38, p = 0.01) had increased risk of death, but BMI > 30 did not. In models assessing premorbid BMI and weight loss, increasing amounts of weight loss were associated with mortality independent of BMI in early cancers. For locally advanced cancers, without weight loss, there was no association with death, regardless of BMI.

CONCLUSION

The predominant driver of mortality across clinical stages is weight loss. The obesity paradox appears to exist in early stage disease only. Future studies should investigate mechanisms for the obesity paradox, accompanying physiologic changes with weight loss preceding diagnosis, and if patients with low BMI and weight loss benefit from early nutritional support.

COL5A2 as a potential clinical biomarker for gastric cancer and renal metastasis

BACKGROUND

Gastric cancer, characterized by insidious onset and multiple metastasis, is almost incurable and has poor prognosis, and also one of the leading causes of treatment failure and death in patients with gastric cancer (GC). However, the prognosis of collagen type V alpha2 chain (COL5A2) in GC and renal metastasis is unknown.

METHODS

Recruited 148 patients who underwent GC. The diagnosis of GC was confirmed by ultrasound imaging and pathological examination. Immunohistochemistry and RT-qPCR were performed to exam the expression level of COL5A2. The statistical methods included Pearson chi-square test, Spearman-rho correlation test, univariate and multivariate cox regression analysis. Finally, this research constructed receiver operating characteristic (ROC) curves and applied the area under the curve (AUC).

RESULTS

Based on Pearson's chi-square test, Spearman-rho test, and univariate/multivariate cox regression, pathologic grade (P < .001), renal metastasis (P < .001) and staging (P < .001) were significantly related to COL5A2. And COL5A2 expression (hazard ratio [HR]: 18.834, P < .001) is an independent risk factor of GC. The AUC was used as the degree of confidence in judging each factor: COL5A2 (AUC = 0.878, P < .001), COL1A1 (AUC = 0.636, P = .006), COL1A2 (AUC = 0.545, P = .368), and COL3A1 (AUC = 0.617, P = .019). Through the ROC result, COL5A2 had more advantage as a biomarker for GC than other collagens.

CONCLUSIONS

COL5A2 gene expression level might be a risk factor for GC. COL5A2 has a strong correlation with the prognosis of the disease.

Ghrelin Affects Gastric Cancer Progression by Activating AMPK Signaling Pathway

As the endogenous ligand for the GH secretagogue receptor (GHSR), Ghrelin is aberrant expressed in multiple malignant carcinoma, and involved in regulating a number of progression of cancer, especially in metastasis and proliferation. However, the precise role of Ghrelin in tumorigenesis of gastric cancer (GC) is still poorly understood. In this study, we extensively investigated the roles and mechanisms of Ghrelin in human gastric cancer. Ghrelin levels in cancer tissues and cell lines were analyzed by immunohistochemistry, qRT-PCR, and Western blot. Functional studies were performed after Ghrelin overexpressed or knockdown in AGS cell line. Cell proliferation was evaluated in by MTT and clone formation assays. The wound healing and Transwell system were used to assess the cell migration and invasive ability of GC cells. Cell apoptosis was detected by flow cytometry, and metabolic assays were performed to reveal the function of Warburg effect in the process. Ghrelin was lowly expressed in gastric cancer tissues and cell lines. Overexpression of Ghrelin inhibited gastric cancer cell proliferation, migration, invasion, and promoted apoptosis by activating the AMPK pathway, while D-[lys3]-GHRP-6 (a GHSR agonist) treatment relieved the effect, promoting tumorigenesis. Ghrelin knockdown increased the glucose uptake and lactic acid release, suggesting that Ghrelin elicited an anti-Warburg effect via AMPK pathway to inhibit gastric tumorigenesis. Ghrelin inhibits cell proliferation, migration, and invasion by eliciting an anti-Warburg effect via AMPK signaling pathway in gastric cancer cells.

Long non-coding RNA ASB16-AS1 inhibits proliferation, migration, and invasion of gastric cancer cells by regulating miR-670-3p/ATXN7L3 axis

BACKGROUND

Many long non-coding RNAs (lncRNAs) have been shown to play a role in suppressing or promoting the progression of gastric cancer (GC). However, there are still a large number of lncRNAs whose roles in the progression of GC are still unclear. Therefore, it is still necessary to identify lncRNAs that affect the proliferation, migration, and invasion of GC cells to provide potential targets for the prevention and treatment of GC.

AIM

To investigate the effect of lncRNA ASB16-AS1 on the proliferation, migration, and invasion of GC cells and the underlying mechanism.

METHODS

The expression levels of ASB16-AS1, miR-670-3p, and ATXN7L3 in human gastric mucosal cell line GES-1 and GC cell lines HGC-27, AGS, and NUGC-4 were detected by real-time fluorescent quantitative PCR (RT-qPCR) and Western blot. HGC-27 cells were divided into si-NC, si-ASB16-AS1, miR-NC, miR-670-3p, si-ATXN7L3, si-ASB16-AS1 + anti-miR-NC, si-ASB16 -AS1 + anti-miR-670-3p, si-ASB16-AS1 + pcDNA-NC, and si-ASB16-AS1 + pcDNA-ATXN7L3 groups. Cell counting kit-8 and transwell assay were used to detect cell viability and migration invasion , respectively. Dual luciferase reportor assay, RT-qPCR, and Western blot were used to determine the interaction between ASB16-AS1 and miR-670-3p and between miR-670-3p and ATXN7L3.

RESULTS

ASB16-AS1 and ATXN7L3 were highly expressed in GC cells, while miR-670-3p was lowly expressed (P < 0.05). After inhibiting the expression of ASB16-AS1, overexpressing miR-670-3p, or inhibiting the expression of ATXN7L3, the proliferation, migration, and invasion of HGC-27 cells were significantly reduced (P < 0.05). ASB16-AS1 targets and negatively regulates miR-670-3p expression. MiR-670-3p targets and negatively regulates ATXN7L3 expression. Inhibiting miR-670-3p partially reversed the effects of inhibiting ASB16-AS1 on the proliferation, migration, and invasion of HGC-27 cells (P < 0.05). Overexpressing ATXN7L3 partially reversed the effect of inhibiting ASB16-AS1 on the proliferation, migration, and invasion of HGC-27 cells (P < 0.05).

CONCLUSION

Inhibiting ASB16-AS1 inhibits the proliferation, migration, and invasion of GC cells by regulating the miR-670-3p/ATXN7L3 axis.

Circular RNA circMAN2B2 promotes growth and migration of gastric cancer cells by down-regulation of miR-145

Background

CircMAN2B2 is a newly discovered circRNA that has been found to be an oncogene in lung cancer and glioma. The present study was designed to reveal the role of circMAN2B2 in gastric carcinoma (GC).

Methods

qRT‐PCR method was utilized to examine circMAN2B2 expression in GC tissues and paracancerous tissues. Next, circMAN2B2 expression in SNU‐16 and AGS cells was silenced by transfection. CCK‐8 assay, colony formation assay, flow cytometer, Transwell assay, and Western blot were conducted for testing cell phenotype changes. Further, the downstream genes and signaling were uncovered by qRT‐PCR and Western blot.

Results

As relative to paracancerous tissues, circMAN2B2 was high‐expressed in GC tissues. Silence of circMAN2B2 clearly declined SNU‐16 and AGS cells viability, survival, migration but enhanced apoptosis. Meanwhile, silence of circMAN2B2 induced the cleavage of caspases (−3 and −9), down‐regulation of MMPs (−2 and −9), and up‐regulation of miR‐145. The impacts of circMAN2B2 silence toward SNU‐16 and AGS cells were attenuated by miR‐145 silence. Moreover, circMAN2B2 silence deactivated PI3K, AKT while activated JNK through regulating miR‐145.

Conclusion

This work presented the oncogenic function of circMAN2B2 in GC cells growth and migration. CircMAN2B2 exerted its function possibly through regulating miR‐145 as well as PI3K/AKT and JNK pathways.