Re-expression of ARHI (DIRAS3) induces autophagy in breast cancer cells and enhances the inhibitory effect of paclitaxel.
BACKGROUND
ARHI is a Ras-related imprinted gene that inhibits cancer cell growth and motility. ARHI is downregulated in the majority of breast cancers, and loss of its expression is associated with its progression from ductal carcinoma in situ (DCIS) to invasive disease. In ovarian cancer, re-expression of ARHI induces autophagy and leads to autophagic death in cell culture; however, ARHI re-expression enables ovarian cancer cells to remain dormant when they are grown in mice as xenografts. The purpose of this study is to examine whether ARHI induces autophagy in breast cancer cells and to evaluate the effects of ARHI gene re-expression in combination with paclitaxel.


METHODS
Re-expression of ARHI was achieved by transfection, by treatment with trichostatin A (TSA) or by a combination of TSA and 5-aza-2'-deoxycytidine (DAC) in breast cancer cell cultures and by liposomal delivery of ARHI in breast tumor xenografts.


RESULTS
ARHI re-expression induces autophagy in breast cancer cells, and ARHI is essential for the induction of autophagy. When ARHI was re-expressed in breast cancer cells treated with paclitaxel, the growth inhibitory effect of paclitaxel was enhanced in both the cell culture and the xenografts. Although paclitaxel alone did not induce autophagy in breast cancer cells, it enhanced ARHI-induced autophagy. Conversely, ARHI re-expression promoted paclitaxel-induced apoptosis and G2/M cell cycle arrest.


CONCLUSIONS
ARHI re-expression induces autophagic cell death in breast cancer cells and enhances the inhibitory effects of paclitaxel by promoting autophagy, apoptosis, and G2/M cell cycle arrest.
Department of Gynecology, Obstetrics and Gynecology, Hospital of Fudan University, Shanghai 200011, PR China.
Chun-Fang
CF
Zou
Luoqi
L
Jia
Hongyan
H
Jin
Ming
M
Yao
Naiqing
N
Zhao
Jin
J
Huan
Zhen
Z
Lu
Robert C
RC
Bast
Youji
Y
Feng
Yinhua
Y
Yu
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001343:Autophagy / Q000187:drug effects / Q000235:genetics*; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000077209:Decitabine; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D017239:Paclitaxel / Q000494:pharmacology*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014183:Transplantation, Heterologous; D020741:rho GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism
D000972:Antineoplastic Agents, Phytogenic; C117386:DIRAS3 protein, human; D006877:Hydroxamic Acids; D049452:Green Fluorescent Proteins; C012589:trichostatin A; D000077209:Decitabine; D020741:rho GTP-Binding Proteins; D001374:Azacitidine; D017239:Paclitaxel
Biochem Pharmacol. 1999 Jun 1;57(11):1215-21
10230764
Cancer Res. 2003 Jul 15;63(14):4174-80
12874023
Cell. 2008 Jan 11;132(1):27-42
18191218
Trends Mol Med. 2009 Mar;15(3):129-38
19231289
Hum Mol Genet. 2003 Aug 1;12(15):1791-800
12874100
Breast Dis. 2006-2007;26:87-98
17473368
N Engl J Med. 2008 Apr 17;358(16):1663-71
18420499
Clin Cancer Res. 2003 Sep 1;9(10 Pt 1):3660-6
14506155
Anticancer Drugs. 2008 Oct;19(9):911-5
18766005
Int J Cancer. 2000 Jun 1;86(5):690-4
10797292
J Clin Invest. 2008 Dec;118(12):3837-40
19033653
Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):214-9
9874798
J Clin Invest. 2008 Dec;118(12):3917-29
19033662
J Clin Oncol. 2008 Dec 1;26(34):5544-52
18955454
Cell Death Differ. 2001 Jun;8(6):569-81
11536007
Oncogene. 2003 May 15;22(19):2897-909
12771940
Autophagy. 2008 Oct;4(7):969-71
18758234