Data from Recurrent Mutations in the MTOR Regulator RRAGC in Follicular Lymphoma Article Swipe
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· 2023
· Open Access
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· DOI: https://doi.org/10.1158/1078-0432.c.6525221
· OA: W4361945295
<div>Abstract<p><b>Purpose:</b> This study was performed to further our understanding of the biological and genetic basis of follicular lymphoma and to identify potential novel therapy targets.</p><p><b>Experimental Design:</b> We analyzed previously generated whole exome sequencing data of 23 follicular lymphoma cases and one transformed follicular lymphoma case and expanded findings to a combined total of 125 follicular lymphoma/3 transformed follicular lymphoma. We modeled the three-dimensional location of RRAGC-associated hotspot mutations. We performed functional studies on novel RRAGC mutants in stable retrovirally transduced HEK293T cells, stable lentivirally transduced lymphoma cell lines, and in <i>Saccharomyces cerevisiae</i>.</p><p><b>Results:</b> We report recurrent mutations, including multiple amino acid hotspots, in the small G-protein RRAGC, which is part of a protein complex that signals intracellular amino acid concentrations to MTOR, in 9.4% of follicular lymphoma cases. Mutations in RRAGC distinctly clustered on one protein surface area surrounding the GTP/GDP–binding sites. Mutated RRAGC proteins demonstrated increased binding to RPTOR (raptor) and substantially decreased interactions with the product of the tumor suppressor gene <i>FLCN</i> (folliculin). In stable retrovirally transfected 293T cells, cultured in the presence or absence of leucine, multiple RRAGC mutations demonstrated elevated MTOR activation as evidenced by increased RPS6KB/S6-kinase phosphorylation. Similar activation phenotypes were uncovered in yeast engineered to express mutations in the RRAGC homolog Gtr2 and in multiple lymphoma cell lines expressing HA-tagged RRAGC-mutant proteins.</p><p><b>Conclusions:</b> Our discovery of activating mutations in RRAGC in approximately 10% of follicular lymphoma provides the mechanistic rationale to study mutational MTOR activation and MTOR inhibition as a potential novel actionable therapeutic target in follicular lymphoma. <i>Clin Cancer Res; 22(21); 5383–93. ©2016 AACR</i>.</p></div>