JOURNAL ARTICLE

Overexpression of miR-200c induces chemoresistance in esophageal cancers mediated through activation of the Akt signaling pathway

Rie Hamano, Hiroshi Miyata, Makoto Yamasaki, Yukinori Kurokawa, Johji Hara, Jeong Ho Moon, Kiyokazu Nakajima, Shuji Takiguchi, Yoshiyuki Fujiwara, Masaki Mori, Yuichiro Doki
Clinical Cancer Research 2011 May 1, 17 (9): 3029-38
21248297

PURPOSE: To determine the relationship between resistance to chemotherapy and microRNA (miRNA) expression in esophageal cancer, we focused on miRNAs known to be associated with maintenance of stem cell function.

EXPERIMENTAL DESIGN: Using 98 formalin-fixed, paraffin-embedded samples obtained from patients with esophageal cancer who had received preoperative chemotherapy followed by surgery, we measured expression levels of several miRNAs that are considered to be involved in the regulation of stem cell function (e.g., let-7a, let-7g, miR-21, miR-134, miR-145, miR-155, miR-200c, miR-203, and miR-296) by real-time reverse transcriptase PCR. Then, we examined the relationship between miRNA expression and prognosis or response to chemotherapy. To investigate the mechanism of miRNA-induced chemoresistance, in vitro assays were carried out using esophageal cancer cells.

RESULTS: Analyses of the 9 miRNAs expression showed that overexpression of miR-200c (P = 0.037), underexpression of miR-145 (P = 0.023), and overexpression of miR-21 (P = 0.048) correlated significantly with shortened overall duration of survival. In particular, miR-200c expression correlated significantly with response to chemotherapy (P = 0.009 for clinical response; P = 0.007 for pathologic response). In vitro assay showed significantly increased miR-200c expression in cisplatin-resistant cells compared with their parent cells (∼1.7-fold). In anti-miR-200c-transfected cells, chemosensitivity to cisplatin and apoptosis after exposure to cisplatin was found to increase as compared with the negative control. Western blotting showed that knockdown of miR-200c expression was associated with increased expression of PPP2R1B, a subunit of protein phosphatase 2A, which resulted in reduced expression of phospho-Akt.

CONCLUSIONS: Results of this study emphasized the involvement of miR-200c in resistance to chemotherapy among esophageal cancers and that this effect was mediated through the Akt pathway.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
21248297
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"