RESUMO
Cancer cells modulate their metabolic networks to support cell proliferation and a higher demand of building blocks. These changes may restrict the availability of certain amino acids for protein synthesis, which can be utilized for cancer therapy. However, little is known about the amino acid demand changes occurring during aggressive and invasive stages of cancer. Recently, we developed diricore, an approach based on ribosome profiling that can uncover amino acid limitations. Here, we applied diricore to a cellular model in which epithelial breast cells respond rapidly to TGFß1, a cytokine essential for cancer progression and metastasis, and uncovered shortage of leucine. Further analyses indicated that TGFß1 treatment of human breast epithelial cells reduces the expression of SLC3A2, a subunit of the leucine transporter, which diminishes leucine uptake and inhibits cell proliferation. Thus, we identified a specific amino acid limitation associated with the TGFß1 response, a vulnerability that might be associated with aggressiveness in cancer.
Assuntos
Códon , Leucina/genética , Leucina/metabolismo , Biossíntese de Proteínas , Ribossomos/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Feminino , Cadeia Pesada da Proteína-1 Reguladora de Fusão/genética , Cadeia Pesada da Proteína-1 Reguladora de Fusão/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Biossíntese de Proteínas/efeitos dos fármacos , Transdução de Sinais , Fator de Crescimento Transformador beta1/farmacologiaRESUMO
Breast cancer is the most prevalent type of malignancy in women with â¼1.7 million new cases diagnosed annually, of which the majority express ERα (ESR1), a ligand-dependent transcription factor. Genome-wide chromatin binding maps suggest that ERα may control the expression of thousands of genes, posing a great challenge in identifying functional targets. Recently, we developed a CRISPR-Cas9 functional genetic screening approach to identify enhancers required for ERα-positive breast cancer cell proliferation. We validated several candidates, including CUTE, a putative ERα-responsive enhancer located in the first intron of CUEDC1 (CUE-domain containing protein). Here, we show that CUTE controls CUEDC1 expression, and that this interaction is essential for ERα-mediated cell proliferation. Moreover, ectopic expression of CUEDC1, but not a CUE-domain mutant, rescues the defects in CUTE activity. Finally, CUEDC1 expression correlates positively with ERα in breast cancer. Thus, CUEDC1 is a functional target gene of ERα and is required for breast cancer cell proliferation.