TY - JOUR
T1 - Differential CARM1 isoform expression in subcellular compartments and among malignant and benign breast tumors
AU - Shlensky, David
AU - Mirrielees, Jennifer A.
AU - Zhao, Zibo
AU - Wang, Lu
AU - Mahajan, Aparna
AU - Yu, Menggang
AU - Sherer, Nathan M.
AU - Wilke, Lee G.
AU - Xu, Wei
N1 - Funding Information:
The authors would like to acknowledge the University of Wisconsin Carbone Cancer Center Translational Science BioCore BioBank including Dr. Ricardo Lloyd and Jodi Knecht for providing clinical breast samples under an IRB-approved human subjects protocol (UW HS IRB 2013–0777), which is supported by the National Institutes of Health. We would also like to acknowledge the University of Wisconsin School of Medicine and Public Health Department of Surgery Shapiro summer research experience program for providing a research opportunity for DS.
Publisher Copyright:
© 2015 Shlensky et al.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - Purpose: Coactivator-associated arginine methyltransferase 1 (CARM1) is a coactivator for ERα and cancer-relevant transcription factors, and can methylate diverse cellular targets including histones. CARM1 is expressed in one of two alternative splice isoforms, full-length CARM1 (CARM1FL) and truncated CARM1 (CARM1ΔE15). CARM1FL and CARM1ΔE15 function differently in transcriptional regulation, protein methylation, and mediation of pre-mRNA splicing in cellular models. Methods: To investigate the functional roles and the prognosis potential of CARM1 alternative spliced isoforms in breast cancer, we used recently developed antibodies to detect differential CARM1 isoform expression in subcellular compartments and among malignant and benign breast tumors. Results: Immunofluorescence in MDA-MB-231 and BG-1 cell lines demonstrated that CARM1ΔE15 is the dominant isoform expressed in the cytoplasm, and CARM1FL is more nuclear localized. CARM1ΔE15 was found to be more sensitive to Hsp90 inhibition than CARM1FL, indicating that the truncated isoform may be the oncogenic form. Clinical cancer samples did not have significantly higher expression of CARM1FL or CARM1ΔE15 than benign breast samples at the level of mRNA or histology. Furthermore neither CARM1FL nor CARM1ΔE15 expression correlated with breast cancer molecular subtypes, tumor size, or lymph node involvement. Conclusions: The analysis presented here lends new insights into the possible oncogenic role of CARM1ΔE15. This study also demonstrates no obvious association of CARM1 isoform expression and clinical correlates in breast cancer. Recent studies, however, have shown that CARM1 expression correlates with poor prognosis, indicating a need for further studies of both CARM1 isoforms in a large cohort of breast cancer specimens.
AB - Purpose: Coactivator-associated arginine methyltransferase 1 (CARM1) is a coactivator for ERα and cancer-relevant transcription factors, and can methylate diverse cellular targets including histones. CARM1 is expressed in one of two alternative splice isoforms, full-length CARM1 (CARM1FL) and truncated CARM1 (CARM1ΔE15). CARM1FL and CARM1ΔE15 function differently in transcriptional regulation, protein methylation, and mediation of pre-mRNA splicing in cellular models. Methods: To investigate the functional roles and the prognosis potential of CARM1 alternative spliced isoforms in breast cancer, we used recently developed antibodies to detect differential CARM1 isoform expression in subcellular compartments and among malignant and benign breast tumors. Results: Immunofluorescence in MDA-MB-231 and BG-1 cell lines demonstrated that CARM1ΔE15 is the dominant isoform expressed in the cytoplasm, and CARM1FL is more nuclear localized. CARM1ΔE15 was found to be more sensitive to Hsp90 inhibition than CARM1FL, indicating that the truncated isoform may be the oncogenic form. Clinical cancer samples did not have significantly higher expression of CARM1FL or CARM1ΔE15 than benign breast samples at the level of mRNA or histology. Furthermore neither CARM1FL nor CARM1ΔE15 expression correlated with breast cancer molecular subtypes, tumor size, or lymph node involvement. Conclusions: The analysis presented here lends new insights into the possible oncogenic role of CARM1ΔE15. This study also demonstrates no obvious association of CARM1 isoform expression and clinical correlates in breast cancer. Recent studies, however, have shown that CARM1 expression correlates with poor prognosis, indicating a need for further studies of both CARM1 isoforms in a large cohort of breast cancer specimens.
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U2 - 10.1371/journal.pone.0128143
DO - 10.1371/journal.pone.0128143
M3 - Article
C2 - 26030442
AN - SCOPUS:84934888396
SN - 1932-6203
VL - 10
JO - PloS one
JF - PloS one
IS - 6
M1 - e0128143
ER -
