Amplified 7q21‐22 gene MCM7 and its intronic miR‐25 suppress COL1A2 associated genes to sustain intestinal gastric cancer features

Abstract

Frequent amplification of 7q21-22 genomic region is known in gastric cancer. Multiple genes including SHFM1, MCM7, and COL1A2 were reported to be the potential cancer candidate genes of this 20 Mb amplicon. This amplicon has two polycistrionic miRNA clusters and in the present study, miR-106b-25 cluster located in intron-13 of MCM7 was identified to express in gastric tumors. Among the 7q21-22 candidate genes, SHFM1 and MCM7 are expressed in intestinal type gastric tumors, whereas COL1A2 is expressed in diffuse type gastric tumors. Across gastric tumors, miR-25 was identified to co-express with MCM7 and SHFM1. On the other hand, negative correlation was observed between miR-25 and COL1A2 expression. miR-25 originating from MCM7 was found capable of selectively targeting the adjacent gene COL1A2. Silencing of miR-25 was found capable of elevating the expression of COL1A2 and inhibiting E-cadherin expression, revealing the diffuse type gastric cancer suppressive role conferred by miR-25. miR-25 was also found to suppress p53, and activate c-Src revealing its intestinal type gastric cancer associated oncogenic functions. Genome-wide expression profiling upon miR-25 silencing reveals that miR-25 is capable of suppressing 40 genes which are co-expressed with COL1A2, involved in epithelial to mesenchymal transition and angiogenesis which are the typical diffuse type gastric cancer features. The results clearly demonstrate 7q21-22 amplification, MCM7, and its intronic miR-25 are the major molecular switches involved in the complex oncogenic circuits of gastric cancer.

Retracted: Silencing of COL1A2, COL6A3, and THBS2 inhibits gastric cancer cell proliferation, migration, and invasion while promoting apoptosis through the PI3k‐Akt signaling pathway

“…Frequent amplification of 7q21‐22 genomic region is common in gastric cancer; among the 7q21‐22 candidate genes, COL1A2 is expressed in diffuse‐type gastric cancer . Previous study suggest that the COL1A2 gene‐set is associated with poor prognosis and thus COL1A2 was a potential biomarker to improve clinical prediction in gastric cancer . Cytogenetic data show that 1p13 is frequently involved in structural aberrations and that 2q37 acts as its most common translocation partner; the genes involved in the translocation t(1;2)(p13;q37) include COL6A3 at 2q37 .…”

Identification of the targeted therapeutic potential of doxycycline for a subset of gastric cancer patients

“…The staining was performed as described previously. 22 The image acquisition was carried out using the Operetta TM High-Content Imaging system (PerkinElmer, Waltham, MA). The experiment was performed thrice in triplicate.…”

Usefulness of serum miR‑1246/miR‑106b ratio in patients with esophageal squamous cell carcinoma

“…miR-106b-5p has been identified as an oncogenic miR in hepatocellular carcinoma, laryngeal carcinoma, breast carcinoma, and glioma ( 38 ). miR-106b is present in the intron of the MCM7 gene and forms a cluster with miR-25 and miR-93 ( 39 , 40 ). Reports on the function of miR-106b are controversial, wherein few report its tumor suppressive function in colorectal and ovarian cancers while others report its action as an oncomir in colorectal and other cancers.…”