PROJECT SUMMARY
Despite advances in clinical detection, breast cancer (BC) is the second leading cause of cancer-related deaths
in women. Importantly, recurrent BC is frequently treatment resistant and has poor survival outcomes. The RON
receptor tyrosine kinase (RTK) overexpressed in 50-93% of human BCs and high levels of RON occur across
all BC subtypes. RON has been shown to be a predictor of BC recurrence, metastasis and poor prognosis in
patients with BC. Overexpression of RON in the mammary epithelium of mice is sufficient to induce highly
metastatic BC in 100% of female mice. Further, we have recently made the novel discovery that RON expression
is sufficient to drive metabolic reprogramming where glycolysis predominates to meet energy demands despite
oxygen availability, however, a connection to RON and metabolism has not been examined. Interestingly,
published studies show that aerobic glycolysis in tumors correlates with therapeutic resistance and BC
recurrence. Moreover, recent studies show that in breast cancer stem-like cells (BCSCs) a shift towards glycolytic
processes over that of oxidative phosphorylation is present. Consistent with this data, our recent data show an
important role for RON signaling in supporting BCSC phenotypes. Given that BCSCs are advocated to be the
cells that evade therapy and lead to recurrence, RON signaling may support recurrence through BCSCs which
we speculate may occur through expression of glycolytic genes. Thus, the long-term goal of this proposal is to
understand how RON expression supports BC recurrence and to exploit this mechanism for therapeutic
intervention, and the overall objective is to elucidate the mechanisms by which RON signaling supports BCSC
phenotypes and to target specific vulnerabilities to reduce BC recurrence. To meet this objective, we will test our
central hypothesis that inhibiting glycolytic metabolism in RON expressing BC will diminish BC recurrence by
targeting BCSCs. We will first determine the mechanism by which RON drives metabolic reprogramming
towards aerobic glycolysis in BC cells, and evaluate the functional significance in BCSCs by evaluating
the RON-dependent requirement of c-Myc and HIF1 on glycolytic gene expression, metabolite composition, and
functional metabolic flux, and examining the consequences of in BCSC phenotypes. Then, we will examine the
susceptibility of RON expressing BC/BCSCs to glycolytic inhibition and ensuing effects on BC
recurrence. This will be performed by targeting LDHA, which we believe will induce feedback mechanisms that
directly affect upstream steps in glycolysis, making it difficult to meet cellular energy needs via aerobic glycolysis.
For recurrence, orthotopically implanted tumors will be surgically resected and recurrent tumors evaluated. LDHA
will be targeted to prevent recurrence and to treat recurrence, in separate experiments. In vitro, we will perform
assays evaluating BCSC-like phenotypes with LDHA targeting that will allow for consideration of therapeutic
potential in eradicating tumor-reconstituting cells, a clinically relevant metric.