The antisense RNA CDH3-AS1 regulates expression of the melanoma suppressor P-cadherin
Thousands of regulatory noncoding RNAs (ncRNAs) have been annotated; however, their functions in gene regulation and contributions to cancer formation remain poorly understood. To gain a better understanding of the influence of ncRNAs on gene regulation during melanoma progression, we mapped the landscape of ncRNAs in melanocytes and melanoma cells. Nearly half of deregulated genes in melanoma are ncRNAs, with antisense RNAs (asRNAs) comprising a large portion of deregulated ncRNAs. CDH3-AS1, the most significantly downregulated asRNA, overlaps the CDH3 gene, which encodes P-cadherin, a transmembrane glycoprotein   involved in cell adhesion that was also reduced in melanoma. Overexpression of CDH3-AS1 increased cell aggregation and reduced xenograft tumor growth, mimicking the tumor-suppressive effects of CDH3. CDH3-AS1 interacted with CDH3 mRNA and enhanced P-cadherin protein levels. Interestingly, secondary structures at the CDH3 5' end regulated P-cadherin translation, and ribosome profiling revealed that CDH3-AS1 promotes ribosome occupancy at the CDH3 5'UTR. Notably, 5'UTR ribosome occupancy was generally increased in mRNAs having cognate asRNA. Taken together, this study revealed the CDH3-AS1-mediated enhancement of P-cadherin translation, underscoring the broader potential of asRNAs as regulators of protein-coding genes and their role in diseases like melanoma. Overall design: Comparison of Ribosome density in Hermes melanocytes treated with either control siRNA or siRNA targeting CDH3-AS1.