Project Summary The pathways that regulate processes necessary for wound healing, such as proliferation and migration, are often co-opted by tumors, leading to their description as wounds that do not heal. Therefore, identifying novel genes involved in wound healing and understanding how they are dysregulated in cancer may provide new targets for therapeutic efforts. We recently discovered thousands of small open reading frames that encode proteins <100 amino acids, dubbed microproteins. Among these was a 10 kDa microprotein encoded on the lncRNA Terminal Differentiation-Induced non-coding RNA (TINCR), which is a critical inducer of terminal differentiation in the epidermis and regulator of cancer cell proliferation and migration. TINCR microprotein (TINCR-MP) is highly conserved across mammals, strongly suggesting that it is functional. Compelling preliminary data demonstrate that in human skin models TINCR-MP downregulates signaling pathways involved in wound healing, and that it interacts with histone modifying enzymes that have functions in differentiation and cancer. Furthermore, while TINCR-MP is expressed during epidermal differentiation, it is unnecessary for differentiation, making its function separate from the differentiation promoting activity of TINCR RNA. The central hypothesis is that TINCR-MP acts as a brake for proliferation and migration during wound healing through alterations to the epigenetic landscape, and that this function is hijacked in cancer cells to promote tumor progression. The goals of this proposal are thus: 1) to determine the role of TINCR-MP in cutaneous wound repair processes, and establish whether TINCR-MP effects on wound healing are driven by epigenetic modifications, 2) to determine the extent to which TINCR-MP regulates proliferation and migration in prostate and breast cancer cell lines, and establish its effects on epigenetic and subsequent gene expression changes, and 3) to identify additional microproteins regulated during differentiation that affect cancer proliferation. Successful completion of these aims will reveal an important microprotein that functions in wound healing and tumor progression, as well as new microproteins to investigate. The candidate, Dr. Thomas Martinez, plans to develop an independent research program focused on characterizing microproteins that function in both differentiation and cancer. The opportunities offered by this Career Development Award will allow Dr. Martinez to deepen his knowledge of developmental biology, epigenetics, and cancer biology. He will also gain experience utilizing 3D ex vivo skin models, in vivo mouse models, and techniques for analyzing the epigenetic landscape. Dr. Martinez will conduct these studies under the mentorship of Dr. Alan Saghatelian, expert on peptide biology, as well as co-mentors Dr. Diana Hargreaves and Dr. George Sen, experts on chromatin remodeling complexes in disease and epidermal homeostasis, respectively. Dr. Martinez’s Advisory Committee will also help foster his scientific and academic career goals. The Salk Institute provides an ideal environment with expertly run core facilities and ample seminars and workshops to prepare trainees for independent academic careers.

Project Narrative Advances in genomics and proteomics have uncovered thousands of previously unannotated small proteins, many of which are encoded on genes implicated in cancer. This proposal seeks to characterize the mechanism of one such novel microprotein with roles in cutaneous wound healing and tumor progression. Successful completion of these studies will enhance our knowledge of how regulators of wound healing are hijacked by cancer, and may provide a new target for the development of cancer therapies.