Anti-ERBB2 sh-RNA suppress both cell growth and tumor growth in ERBB2-overexpressing upper gastrointestinal adenocarcinomas

ADAM10 expression in gastric adenocarcinoma: Results of a curative gastrectomy cohort

Objective:

Gastric cancer is among the most common human cancers with high mortality rates. ADAM10, a member of the ADAM (a disintegrin and metalloproteinase) family has also been found to be associated with gastric carcinoma and has been suggested as a potential therapeutic target. Here, we investigated the association of ADAM10 expression with prognosis in gastric adenocarcinoma patients that underwent gastric resection with D2 lymph node dissection.

Methods:

Total 86 consecutive patients that underwent resection for gastric adenocarcinoma were included. Immunohistochemical ADAM10 expression and its association with clinicopathological parameters were analyzed. Univariate and multivariate analyses and survival analyses were performed using SPSS ver.22.

Results:

High grade tumors, advanced stage tumors and diffuse type tumors showed significantly worse prognosis. A statistically significant association between ADAM10 expression and overall survival (OS) was observed in the univariate analysis, however, this association did not maintain its significance in the multivariate analysis. No statistically significant association was found ADAM-10 expression and clinicopathological parameters.

Conclusion:

Immunohistochemical ADAM10 expression may be used as a prognostic marker in gastric adenocarcinoma, however, introduction of a standardized immunohistochemical scoring system seems to be necessary for evaluation of ADAM10 staining.

Lysine-specific demethylase (LSD1/KDM1A) and MYCN cooperatively repress tumor suppressor genes in neuroblastoma

The chromatin-modifying enzyme lysine-specific demethylase 1, KDM1A/LSD1 is involved in maintaining the undifferentiated, malignant phenotype of neuroblastoma cells and its overexpression correlated with aggressive disease, poor differentiation and infaust outcome. Here, we show that LSD1 physically binds MYCN both in vitro and in vivo and that such an interaction requires the MYCN BoxIII. We found that LSD1 co-localizes with MYCN on promoter regions of CDKN1A/p21 and Clusterin (CLU) suppressor genes and cooperates with MYCN to repress the expression of these genes. KDM1A needs to engage with MYCN in order to associate with the CDKN1A and CLU promoters. The expression of CLU and CDKN1A can be restored in MYCN-amplified cells by pharmacological inhibition of LSD1 activity or knockdown of its expression. Combined pharmacological inhibition of MYCN and LSD1 through the use of small molecule inhibitors synergistically reduces MYCN-amplified Neuroblastoma cell viability in vitro. These findings demonstrate that LSD1 is a critical co-factor of the MYCN repressive function, and suggest that combination of LSD1 and MYCN inhibitors may have strong therapeutic relevance to counteract MYCN-driven oncogenesis.

MET activation mediates resistance to lapatinib inhibition of HER2-amplified gastric cancer cells

HER2 amplification is found in more than 15% of gastric cancers and is associated with poor clinical outcome. Lapatinib, a dual HER2 and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has shown promising in vitro results in treating HER2(+) cancer cells. However, several studies have shown that activation of alternative receptor tyrosine kinases can mediate resistance to HER-targeted therapy. Here, we investigated whether activated MET can confer resistance to lapatinib inhibition of gastric cancer cells. A panel of gastric cancer cell lines was treated with lapatinib, and we observed that cell proliferation was reduced by 70% and that the degree of HER2 amplification corresponds to sensitivity to lapatinib. Immunoblotting analysis indicated that phosphorylation of HER2, EGFR, MET, AKT, and extracellular signal-regulated kinase was inhibited by lapatinib and presumably led to cell-cycle arrest as observed with flow cytometry. Hepatocyte growth factor (HGF) activation of MET receptors rescued cells from lapatinib-induced growth inhibition by restimulating the downstream pathways and restoring normal cell-cycle progression. This rescue effect could be abrogated by inhibiting MET with PHA-665752 (a highly specific MET inhibitor) or downregulating MET expression with short interfering RNA. No synergy in growth inhibition was observed when cells were treated with a combination of lapatinib and PHA-665752. Repeat studies using insulin-like growth factor 1 and fibroblast growth factor 3 could not uniformly rescue the lapatinib-treated gastric cancer cells. In conclusion, HGF/MET-mediated resistance to lapatinib is a novel mechanism of resistance to HER2-targeted agents in gastric cancer cells. Development of inhibitors targeting multiple receptors or common downstream signaling proteins merits further investigation.

ADAM 10 is associated with gastric cancer progression and prognosis of patients

BACKGROUND

The metalloproteinase domain-containing protein 10 (ADAM 10) has been implicated in the development and progression of gastric cancer.

METHODS

Expression of ADAM 10 and C-erbB-2 were examined immunochemically in 436 clinicopathologically characterized gastric cancer cases.

RESULTS

Protein levels of ADAM 10 and C-erbB-2 were up-regulated in gastric cancer lesions compared with adjacent non-cancerous tissues. Positive expression of ADAM 10 correlated with age, size of tumor, location of tumor, depth of invasion, vessel invasion, lymph node, and distant metastasis and TNM stage, and also with expression of C-erbB-2. In stages I, II, and III, the 5-year survival rate of patients with high ADAM 10 expression was significantly lower than in patients with low expression. However, in stage IV, ADAM 10 expression did not correlate with the 5-year survival rate. Further multivariate analysis suggests that up-regulation of ADAM 10 and C-erbB-2 were independent prognostic indicators for the disease, along with depth of invasion, lymph node and distant metastasis and TNM stage.

CONCLUSION

Expression of ADAM 10 in gastric cancer is significantly associated with lymph node and distant metastasis, high C-erbB-2 expression, and poor prognosis. ADAM 10 and C-erbB-2 proteins could be useful markers to predict tumor progression and prognosis.

Genetic and epigenetic alteration in gastric carcinogenesis

Gastric cancer (GC) is an important cause of morbidity and mortality worldwide. In addition to environmental factors, genetic factors also play an important role in GC etiology, as demonstrated by the fact that only a small proportion of individuals exposed to the known environmental risk factors develop GC. Molecular studies have provided evidence that GC arises not only from the combined effects of environmental factors and susceptible genetic variants but also from the accumulation of genetic and epigenetic alterations that play crucial roles in the process of cellular immortalization and tumorigenesis. This review is intended to focus on the recently described basic aspects that play key roles in the process of gastric carcinogenesis. Genetic variation in the genes DNMT3A, PSCA, VEGF, and XRCC1 has been reported to modify the risk of developing gastric carcinoma. Several genes have been newly associated with gastric carcinogenesis, both through oncogenic activation (MYC, SEMA5A, BCL2L12, RBP2 and BUBR1) and tumor suppressor gene inactivation mechanisms (KLF6, RELN, PTCH1A, CLDN11, and SFRP5). At the level of gastric carcinoma treatment, the HER-2 tyrosine kinase receptor has been demonstrated to be a molecular target of therapy.