Peptide antibody tools to dissect specific functions of eIF4A paralogs in cancer.

Eukaryotic translation initiation factors (eIFs) are key regulators of messenger RNA (mRNA) translation, a process highly dysregulated in cancer. Among these paralogs, eIF4A1 and eIF4A2 are closely related DEAD box mRNA helicases that, despite their high sequence identity, play distinct roles in cellular homeostasis and tumorigenesis. In the context of triple-negative breast cancer (TNBC), where dysregulated protein translation drives tumor progression and metastasis, high rate of relapse, and resistance to radio- and chemotherapy, an understanding of the unique contributions of eukaryotic initiation factor 4 A (eIF4A) paralogs is important. Current commercial antibodies are not validated to claim the specificity towards these helicases. To address this, we developed and validated paralog-specific antibodies to unequivocally detect eIF4A1 and eIF4A2 by leveraging unique sequence differences in their N-terminal regions. Using affinity-purified, rabbit peptide-antibody generation followed by validation through immunoblot analyses of knockout and knockdown cellular lysates, we confirmed the high specificity of the antibodies and the absence of any cross-reactivity. These results establish that these antibodies are invaluable tools for dissecting the distinct roles of eIF4A1 and eIF4A2 in translational control and potential therapeutic strategies targeting these factors to overcome chemoresistance, primary tumor progression, and metastasis. This study provides a foundation for future investigations into the functional divergence of eIF4A paralogs, their functional ramifications in cancer, and their implications in tumor progression and metastasis.