PMID- 27510461
OWN - NLM
STAT- MEDLINE
DCOM- 20170714
LR  - 20240326
IS  - 1520-5010 (Electronic)
IS  - 0893-228X (Print)
IS  - 0893-228X (Linking)
VI  - 29
IP  - 9
DP  - 2016 Sep 19
TI  - Silencing KRAS Overexpression in Cadmium-Transformed Prostate Epithelial Cells 
      Mitigates Malignant Phenotype.
PG  - 1458-67
LID - 10.1021/acs.chemrestox.6b00137 [doi]
AB  - Cadmium (Cd) is a potential human prostate carcinogen. Chronic Cd exposure 
      malignantly transforms RWPE-1 human prostate epithelial cells into CTPE cells by 
      an unclear mechanism. Previous studies show that RWPE-1 can also be malignantly 
      transformed by arsenic, and KRAS activation is key to causation and maintenance 
      of this phenotype. Although Cd and arsenic can both transform prostate epithelial 
      cells, it is uncertain whether their mechanisms are similar. Thus, here we 
      determined whether KRAS activation is critical in causing and maintaining 
      Cd-induced malignant transformation in CTPE cells. Expression of KRAS, miRNAs, 
      and other genes of interest was analyzed by Western blot and RT-PCR. Following 
      stable KRAS knockdown (KD) by RNA interference using shRNAmir, the malignant 
      phenotype was assessed by various physical and genetic parameters. CTPE cells 
      greatly overexpressed KRAS by 20-fold, indicating a likely role in Cd 
      transformation. Thus, we attempted to reverse the malignant phenotype via KRAS 
      KD. Two weeks after shRNAmir transduction, KRAS protein was undetectable in CTPE 
      KD cells, confirming stable KD. KRAS KD reduced stimulated RAS/ERK and PI3K/AKT 
      signaling pathways and markedly mitigated multiple physical and molecular 
      malignant cell characteristics including: hypersecretion of MMP-2, colony 
      formation, cell survival, and expression of cancer-relevant genes (reduced 
      proliferation and cell cycle-related genes; activated tumor suppressor PTEN). 
      However, KRAS KD did not reverse miRNA expression originally down-regulated by Cd 
      transformation. These data strongly suggest KRAS is a key gene in development and 
      maintenance of the Cd-induced malignant phenotype, at least in the prostate. It 
      is not, however, the only genetic factor sustaining this phenotype.
FAU - Ngalame, Ntube N O
AU  - Ngalame NN
AD  - Stem Cell Toxicology Group, National Toxicology Program Laboratory, Division of 
      the National Toxicology Program, National Institute of Environmental Health 
      Sciences , Research Triangle Park, North Carolina 27709, United States.
FAU - Waalkes, Michael P
AU  - Waalkes MP
AD  - Stem Cell Toxicology Group, National Toxicology Program Laboratory, Division of 
      the National Toxicology Program, National Institute of Environmental Health 
      Sciences , Research Triangle Park, North Carolina 27709, United States.
FAU - Tokar, Erik J
AU  - Tokar EJ
AD  - Stem Cell Toxicology Group, National Toxicology Program Laboratory, Division of 
      the National Toxicology Program, National Institute of Environmental Health 
      Sciences , Research Triangle Park, North Carolina 27709, United States.
LA  - eng
GR  - ZIA ES102925-06/Intramural NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Intramural
DEP - 20160819
PL  - United States
TA  - Chem Res Toxicol
JT  - Chemical research in toxicology
JID - 8807448
RN  - 0 (KRAS protein, human)
RN  - 00BH33GNGH (Cadmium)
RN  - EC 3.6.5.2 (Proto-Oncogene Proteins p21(ras))
SB  - IM
MH  - Cadmium/chemistry/toxicity
MH  - Cell Line
MH  - Cell Proliferation/genetics
MH  - Cell Transformation, Neoplastic/drug effects/*genetics
MH  - Epithelial Cells/pathology/*physiology
MH  - Gene Expression/genetics
MH  - Gene Knockdown Techniques
MH  - *Gene Silencing
MH  - Humans
MH  - Male
MH  - Prostate/*physiopathology
MH  - Prostatic Neoplasms/*physiopathology
MH  - Proto-Oncogene Proteins p21(ras)/*genetics/*metabolism
MH  - Signal Transduction/genetics
PMC - PMC5576187
MID - NIHMS897547
COIS- Notes The authors declare no competing financial interest.
EDAT- 2016/08/12 06:00
MHDA- 2017/07/15 06:00
PMCR- 2017/08/30
CRDT- 2016/08/12 06:00
PHST- 2016/08/12 06:00 [entrez]
PHST- 2016/08/12 06:00 [pubmed]
PHST- 2017/07/15 06:00 [medline]
PHST- 2017/08/30 00:00 [pmc-release]
AID - 10.1021/acs.chemrestox.6b00137 [doi]
PST - ppublish
SO  - Chem Res Toxicol. 2016 Sep 19;29(9):1458-67. doi: 10.1021/acs.chemrestox.6b00137. 
      Epub 2016 Aug 19.