Project Summary/Abstract
Metastasis is the process in which disseminated tumor cells (DTCs) spread to distal tissues and organs, and it
is the leading cause of cancer-related deaths. In order to complete the metastatic cascade, DTCs must be able
to invade distal sites, initiate tumor growth, proliferate, and promote a tumor microenvironment (TME) to evade
immune surveillance and promote angiogenesis. Elucidating novel mechanisms that underlie these metastatic
phenotypes in DTCs can identify key drivers of metastasis, as well as potential therapeutic vulnerabilities which
can better target metastatic tumors. My dissertation research focuses on elucidating the mechanisms in which
the lncRNA BORG (BMP/OP-Responsive Gene) drives breast cancer (BC) metastasis. My studies determined
that metastatic BC cells are reliant upon BORG complexing with E3 SUMO ligase TRIM28 to induce breast
cancer stem cells (BCSCs) to expand and self-renew both in vitro and in vivo. This work establishes BORG as
a novel driver of BCSCs, and therefore increases our understanding of the mechanisms driving the accumulation
of these malignant cell populations. My recent preliminary data suggests BORG:TRIM28 complexes
downregulate the expression of splicing factors in BC cells, which contributes to BCSC phenotypes. Interestingly,
accumulating evidence indicates that dysregulation of RNA splicing, a complex molecular tool that can control
cellular phenotypes through transcriptomic regulatory mechanisms, contributes to a variety of tumorigenic
phenotypes and even metastatic relapse. Therefore, during the F99 portion of this proposal, I seek to elucidate
the mechanism whereby BORG:TRIM28 complexes dysregulate RNA splicing operant in driving metastatic and
BCSC phenotypes in BC. To complete this research during my dissertation, I will (i) determine which splicing
factors dysregulated by BORG:TRIM28 complexes drive metastatic phenotypes in BC in vitro and in vivo, and
(ii) use RNAseq and subsequent validation to determine the specific alternative splicing events affected by a
subset of these splicing factors in BORG-expressing cells. This work will identify novel mechanisms of RNA
splicing regulation that play key roles in metastatic phenotypes of BC cells. During the K00 phase of this proposal,
I plan to work closely with my postdoctoral mentor to elucidate the mechanisms in which RNA splicing contributes
to tumor cell crosstalk with the TME to promote immune evasion and subsequent metastatic outgrowth.
Specifically, I plan to elucidate (i) how alternative splicing in tumor cells drive changes in the metastatic TME to
promote immune evasion, and (ii) how alternative splicing changes in TME cells, such as T cells and fibroblasts,
contribute to the metastatic niche and subsequent metastatic outgrowth. The current and future goals of my
research are to elucidate mechanisms in which dysregulated RNA splicing contributes to metastatic seeding and
outgrowth in aggressive cancers. My predoctoral and postdoctoral research will provide me with expertise in the
role of RNA splicing in cancer metastasis, and provide me with essential research and professional skills to
launch me into my independent research career at a leading research institute.