Vasohibin 2 reduces chemosensitivity to gemcitabine in pancreatic cancer cells via Jun proto-oncogene dependent transactivation of ribonucleotide reductase regulatory subunit M2.
Vasohibin 2 (VASH2) has previously been identified as an agiogenenic factor and a cancer related protein. Here we investigated the association of VASH2 expression and chemoresistance in pancreatic cancer.



Immunohistochemical staining for VASH2 was performed on 102 human pancreatic cancer samples. Pancreatic cancer cell line models exhibiting overexpression or knockdown of VASH2 were generated. Gene expression analyses were carried out to determine genes differentially regulated by VASH2. Putative transcription factors that are downstream mediators of gene expression regulated by VASH2 were queried bioinformatically. Dual-luciferase reporter assays and ChIP assays were performed to confirm transactivation of target genes following VASH2 overexpression or knockdown.



VASH2 protein expression was higher in human pancreatic cancer than in paired adjacent tissues and elevated VASH2 levels were associated with gemcitabine chemoresistance. In cell line models of pancreatic cancer, VASH2 expression induced gemcitabine chemoresistance in vitro and in vivo. It was discovered that expression of ribonucleotide reductase regulatory subunit M2 (RRM2) is regulated by VASH2; immunohistochemical analysis demonstrated a positive association of VASH2 expression and RRM2 expression in human pancreatic cancer tissues. Bioinformatics analyses revealed that induction of the Jun proto-oncogene (JUN) by VASH2 is responsible for upregulation of RRM2 expression; this JUN-dependent regulation of RRM2 by VASH2 was confirmed by chromatin immunoprecipitation and dual luciferase reporter assays, which demonstrated that JUN directly binds with the RRM2 promoter to activate transcription.



These data suggest that VASH2 reduces the chemosensitivity to gemcitabine in pancreatic cancer cells via JUN-dependent transactivation of RRM2.
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Min
0000-0003-1017-8825
M
Tu
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Haifeng
H
Li
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Nan
N
Lv
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Chunhua
C
Xi
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Zipeng
Z
Lu
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Jishu
J
Wei
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Jianmin
J
Chen
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Feng
F
Guo
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Kuirong
K
Jiang
Department of Pathology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
Guoxin
G
Song
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China. gao11@hotmail.com.
Wentao
W
Gao
Pancreas Center, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 210029, People's Republic of China. miaoyi@njmu.edu.cn.
Yi
Y
Miao
D042501:Angiogenic Proteins / Q000235:genetics*; D000818:Animals; D045744:Cell Line, Tumor; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D051379:Mice; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D000090063:Proto-Oncogene Mas; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D012262:Ribonucleoside Diphosphate Reductase / Q000235:genetics*; D015533:Transcriptional Activation; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
D042501:Angiogenic Proteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D016755:Proto-Oncogene Proteins c-jun; C574858:VASH2 protein, human; D003841:Deoxycytidine; C093713:ribonucleotide reductase M2; D012262:Ribonucleoside Diphosphate Reductase; D000093542:Gemcitabine
Gemcitabine; Jun proto-oncogene; Pancreatic cancer; Ribonucleotide reductase regulatory subunit M2; Vasohibin 2