Mandar Deepak Muzumdar, MD

Despite innovations in combination chemotherapy, targeted therapies, and immunotherapies, most advanced cancers remain incurable. Deciphering the mechanisms that govern the initiation, progression, and maintenance of cancer will facilitate the development of novel strategies for prevention and therapy.

For cancers to arise, cells must acquire the capacity for sustained proliferation while overcoming both intrinsic evolutionary constraints and constraints imposed by the host environment. These properties may be attained through the sequential acquisition of genetic mutations in proto-oncogenes and tumor suppressor genes. Comprehensive genome sequencing efforts have catalogued human cancer mutations, enabling the use of therapies that target these mutated oncoproteins. Nonetheless, cancers frequently evade target inhibition. We demonstrated, for example, that pancreatic cancer cells tolerate genetic ablation of their initiating oncogene KRAS through rewiring of signal transduction. Similar adaptive mechanisms (signaling-based, transcriptional, epigenetic, and metabolic) play a critical role in the maintenance of advanced cancers in the absence of new mutations. In contrast, how non-mutational adaptations impact the earlier stages of tumorigenesis remains poorly understood.

Using genetically-engineered mouse models that closely recapitulate human lung and pancreatic cancers, we have shown that gene mutations are permissive, but insufficient, to drive clonal cancer evolution, consistent with the need for additional cellular adaptations. Furthermore, we have demonstrated that host adaptations to environmental stresses, such as diet and obesity, may facilitate tumor progression in the absence of new mutations. Our research focuses on elucidating the molecular basis of these tumor cell and host adaptations in hopes of defining new approaches for the prevention and treatment of these recalcitrant cancers.