FAM83B mediates EGFR- and RAS-driven oncogenic transformation
Rocky Cipriano, … , George R. Stark, Mark W. Jackson
Rocky Cipriano, … , George R. Stark, Mark W. Jackson
Published August 13, 2012
Citation Information: J Clin Invest. 2012;122(9):3197-3210. https://doi.org/10.1172/JCI60517.
View: Text | PDF
Research Article

FAM83B mediates EGFR- and RAS-driven oncogenic transformation

Abstract

Aberrant regulation of growth signaling is a hallmark of cancer development that often occurs through the constitutive activation of growth factor receptors or their downstream effectors. Using validation-based insertional mutagenesis (VBIM), we identified family with sequence similarity 83, member B (FAM83B), based on its ability to substitute for RAS in the transformation of immortalized human mammary epithelial cells (HMECs). We found that FAM83B coprecipitated with a downstream effector of RAS, CRAF. Binding of FAM83B with CRAF disrupted CRAF/14-3-3 interactions and increased CRAF membrane localization, resulting in elevated MAPK and mammalian target of rapamycin (mTOR) signaling. Ablation of FAM83B inhibited the proliferation and malignant phenotype of tumor-derived cells or RAS-transformed HMECs, implicating FAM83B as a key intermediary in EGFR/RAS/MAPK signaling. Analysis of human tumor specimens revealed that FAM83B expression was significantly elevated in cancer and was associated with specific cancer subtypes, increased tumor grade, and decreased overall survival. Cumulatively, these results suggest that FAM83B is an oncogene and potentially represents a new target for therapeutic intervention.

Authors

Rocky Cipriano, James Graham, Kristy L.S. Miskimen, Benjamin L. Bryson, Ronald C. Bruntz, Sarah A. Scott, H. Alex Brown, George R. Stark, Mark W. Jackson

×

Figure 8

RAS-mediated transformation requires FAM83B expression.

Options: View larger image (or click on image) Download as PowerPoint
RAS-mediated transformation requires FAM83B expression. (A) HME1 cells e...
(A) HME1 cells expressing SV40 Large T (HME1-T) were infected with a retrovirus encoding RAS, or a control (vector; Vec). The RAS-expressing HME1-T cells (HME1-TRAS) were subsequently infected with lentiviruses encoding shRNA targeting FAM83B (denoted B1 and B2) or GFP. The cells were plated for 5 days, and growth was assessed. Northern analysis confirmed the knockdown of FAM83B mRNA relative to the control shRNA. (B) HME1-TRAS cells expressing either GFP or FAM83B-Res.1 (resistant to shRNA1) were infected with lentiviruses encoding shRNA targeting FAM83B or GFP, and growth was assessed. (C) HME1-T cells expressing vector, RAS alone, or RAS together with shRNAs targeting FAM83B or GFP were assessed for AIG. Original magnification, ×10. (D) BJ-ERT cells were infected with a lentivirus expressing a shRNA targeting p53. These cells were subsequently infected with lentiviruses encoding control or FAM83B shRNA and assessed for AIG. Original magnification, ×10. (E) HME1 cells expressing RAS were infected with lentiviruses encoding shRNA targeting GFP, FAM83B, or CRAF. The cells were plated for 5 days, and growth was assessed. (F) HME1 cells expressing RAS were infected with lentiviruses encoding shRNA targeting GFP, FAM83B, or CRAF and assessed for AIG. (G) Northern analysis of FAM83A and FAM83B in BJ fibroblasts expressing hTERT alone (BJ-T) or together with adenoviral E1A and RAS (BJ-ERT). (H and I) HCT116 (colon), PANC02.03 (pancreatic), and A549 (lung) cancer cells were infected with lentiviruses encoding shRNA targeting GFP or FAM83B and assessed for growth and AIG.