Aberrant hypermethylation of<i>miR-9</i>genes in gastric cancer

Tsai, Kuo‐Wang; Liao, Yu-Lun; Wu, Chew-Wun; Hu, Ling-Yueh; Li, Sung‐Chou; Chan, Wen-Ching; Ho, Meng‐Ru; Lai, Chun-Hung; Kao, Hsien Ming; Fang, Wen-Liang; Huang, Kai; Lin, Wen-Chiao

doi:10.4161/epi.6.10.16535

Cited by 105 publications

(95 citation statements)

References 37 publications

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“…Following a bioinformatic search for candidate CpG islands 5= of miRNA genes, it was initially shown that the mir-9-1 gene was hypermethylated in primary invasive breast tumors (22). Additional studies have since shown that mir-9 loci are epigenetically silenced in gastric tumors (9), breast mammosphere models (23), oral squamous cell carcinoma (24), and non-small-cell lung cancers, where methylation of mir-9-3 can serve as a prognostic indicator (25,26). To see if methylation was a contributing silencing mechanism in our system, we first treated cells with the methyltransferase inhibitor 5-aza-2=-deoxycytidine (5AZA).…”

Section: Resultsmentioning

confidence: 99%

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MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

Zawistowski

Nakamura

Parker

et al. 2013

Molecular and Cellular Biology

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MEK1/2 inhibitors such as AZD6244 are in clinical trials for the treatment of multiple cancers, including breast cancer. Targeted kinase inhibition can induce compensatory kinome changes, rendering single therapeutic agents ineffective. To identify target proteins to be used in a combinatorial approach to inhibit tumor cell growth, we used a novel strategy that identified microRNAs (miRNAs) that synergized with AZD6244 to inhibit the viability of the claudin-low breast cancer cell line MDA-MB-231. Screening of a miRNA mimic library revealed the ability of miR-9-3p to significantly enhance AZD6244-induced extracellular signalregulated kinase inhibition and growth arrest, while miR-9-3p had little effect on growth alone. Promoter methylation of mir-9 genes correlated with low expression of miR-9-3p in different breast cancer cell lines. Consistent with miR-9-3p having synthetic enhancer tumor suppressor characteristics, miR-9-3p expression in combination with MEK inhibitor caused a sustained loss of c-MYC expression and growth inhibition. The ␤ 1 integrin gene (ITGB1) was identified as a new miR-9-3p target, and the growth inhibition seen with small interfering RNA knockdown or antibody blocking of ITGB1 in combination with MEK inhibitor phenocopied the growth inhibition seen with miR-9-3p plus AZD6244. The miRNA screen led to identification of a druggable protein, ITGB1, whose functional inhibition synergizes with MEK inhibitor.

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Section: Resultsmentioning

confidence: 99%

“…These data suggested that promoter methylation contributed to the low level of miR-9-3p in claudin-low cells. To validate this suggestion, we performed COBRA (9,27) (Fig. 2D).…”

Section: Resultsmentioning

confidence: 99%

MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

Zawistowski

Nakamura

Parker

et al. 2013

Molecular and Cellular Biology

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“…miR-9-positive cell numbers are increased in metastatic human primary SCCs and SCC metastases. It has been reported that miR-9 is frequently methylated in human cancers, including SCCs, and as such, miR-9 has been suggested to be a tumor suppressor (42)(43)(44). The effect of miR-9 on the metastatic behavior of SCCs observed in our animal model and in the human SCC cell lines prompted us to examine whether miR-9 was elevated in human SCCs.…”

Section: K15kras G12d Smad4 -/-Sccs Retained Csc Populations But Mmentioning

confidence: 99%

Epithelial stem cell mutations that promote squamous cell carcinoma metastasis

et al. 2013

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Squamous cell carcinomas (SCCs) originate in stratified epithelia, with a small subset becoming metastatic. Epithelial stem cells are targets for driver mutations that give rise to SCCs, but it is unknown whether they contribute to oncogenic multipotency and metastasis. We developed a mouse model of SCC by targeting two frequent genetic mutations in human SCCs, oncogene Kras G12D activation and Smad4 deletion, to mouse keratin 15-expressing (K15 + ) stem cells. We show that transgenic mice developed multilineage tumors, including metastatic SCCs. Among cancer stem cell-enriched (CSC-enriched) populations, those with increased side population (SP) cells correlated with epithelial-mesenchymal transition (EMT) and lung metastasis. We show that microRNA-9 (miR-9) contributed to SP expansion and metastasis, and miR-9 inhibition reduced the number of SP cells and metastasis. Increased miR-9 was detected in metastatic human primary SCCs and SCC metastases, and miR-9-transduced human SCC cells exhibited increased invasion. We identified α-catenin as a predominant miR-9 target. Increased miR-9 in human SCC metastases correlated with α-catenin loss but not E-cadherin loss. Our results demonstrate that stem cells with Kras G12D activation and Smad4 depletion can produce tumors that are multipotent and susceptible to EMT and metastasis. Additionally, tumor initiation and metastatic properties of CSCs can be uncoupled, with miR-9 regulating the expansion of metastatic CSCs. IntroductionSquamous cell carcinomas (SCCs) are derived from stratified epithelia present within the skin and oral cavity. A subset of aggressive SCCs become metastatic and lead to metastasis-associated death. The rate of metastasis in skin SCCs ranges from 0.1% to 10% (1), with poorly differentiated tumors and those with greater vertical tumor thickness having an increased risk of metastasis (2). Genetic alterations and intrinsic tumor cell properties controlling SCC metastasis are largely unknown. Genetically engineered mice provide a powerful tool for dissecting driver mutations that contribute to SCC initiation and metastasis. To date, very few genetic mutations causing spontaneous SCC formation and metastasis have been found, particularly metastasis to the lung, which is the leading cause of SCC-associated death (3). Mice with a Smad4 deletion in stratified epithelia develop spontaneous SCCs in the skin, oral cavity, and forestomach (4-6). Among these models, oral SCCs metastasize to lymph nodes (4), whereas skin and forestomach SCCs do not metastasize (5, 6).Because stratified epithelia undergo constant self-renewal and rapid turnover, it is believed that driver mutations for SCCs must initially occur in resident stem cells that renew these epithelia throughout life. In mouse skin, the hair follicle bulge harbors

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“…Downregulation of miRs is a common characteristic observed in various types of cancer, suggesting that these molecules may act as a novel class of tumor suppressors (12)(13)(14)(15)(16)(17)(18). Previous studies have revealed that a growing number of tumor suppressor miRs are inactivated by promoter hypermethylation in cancers (19)(20)(21)(22)(23)(24)(25)(26)(27). One of these miRs, miR-181c, is silenced in gastric cancer by promoter hypermethylation.…”

Section: Introductionmentioning

confidence: 99%

Iodine-125 irradiation inhibits invasion of gastric cancer cells by reactivating microRNA-181c expression

Yang

et al. 2016

Oncology Letters

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Abstract. 125 I) seed implantation has been widely used for the treatment of unresectable advanced tumors. However, the molecular mechanisms underlying the tumor-suppressive effects of 125 I irradiation have not been fully elucidated. The present study demonstrated that 125 I irradiation suppresses cell viability and inhibits cell invasiveness of gastric cancer KATO-III and MKN45 cells. Further mechanistic analysis suggested the involvement of microRNA (miR)-181c in the inhibitory effects induced by 125 I irradiation. Methylated DNA immunoprecipitation coupled with quantitative-polymerase chain reaction demonstrated that treatment with 125 I irradiation, at the dose of 4 Gy, induced promoter demethylation of the miR-181c gene in KATO-III and MKN45 cells. Following irradiation, the expression of miR-181c was significantly increased, which may be attributed to the demethylation caused by 125 I irradiation. In addition, upregulation of miR-181c by administration of miR-181c mimics decreased cell invasion, suggesting the role of miR-181c as a tumor suppressor. More importantly, the tumor-suppressive effects of 125 I irradiation were significantly compromised by the introduction of miR-181c inhibitors. Overall, these results reveal that 125 I irradiation inhibits invasiveness of gastric cancer cells by reactivating miR-181c at the epigenetic level, thereby providing important molecular evidence for the anticancer effects of 125 I irradiation.

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Aberrant hypermethylation ofmiR-9genes in gastric cancer

Cited by 105 publications

References 37 publications

MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

Epithelial stem cell mutations that promote squamous cell carcinoma metastasis

Iodine-125 irradiation inhibits invasion of gastric cancer cells by reactivating microRNA-181c expression

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Aberrant hypermethylation ofmiR-9genes in gastric cancer

Cited by 105 publications

References 37 publications

MicroRNA 9-3p Targets β1 Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

MicroRNA 9-3p Targets β1 Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

Epithelial stem cell mutations that promote squamous cell carcinoma metastasis

Iodine-125 irradiation inhibits invasion of gastric cancer cells by reactivating microRNA-181c expression

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MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition

MicroRNA 9-3p Targets β₁ Integrin To Sensitize Claudin-Low Breast Cancer Cells to MEK Inhibition