Eribulin normalizes pancreatic cancer-associated fibroblasts by simulating TGFβ inhibition

Less than 11% of pancreatic cancer patients survive 5-years post-diagnosis. The unique biology of pancreatic cancer includes a significant expansion of its desmoplastic tumor microenvironment, wherein cancer-associated fibroblasts (CAFs) and their self-produced extracellular matrix are key components. CAF functions are both tumor-supportive and tumor-suppressive, while normal fibroblastic cells are solely tumor-suppressive. Knowing that CAF-eliminating drugs are ineffective and can accelerate cancer progression, therapies that "normalize" CAF function are highly pursued. Eribulin is a well-tolerated anti-microtubule drug used to treat a plethora of neoplasias, including advanced/metastatic cancers. Importantly, eribulin can inhibit epithelial to mesenchymal transition via a mechanism akin to blocking pathways induced by transforming growth factor-beta (TGF{beta}). Notably, canonical TGF{beta} signaling also plays a pivotal role in CAF activation, which is necessary for the development and maintenance of desmoplasia. Hence, we hypothesized that eribulin could modulate, and perhaps "normalize" CAF function. To test this premise, we used a well-established in vivo-mimetic fibroblastic cell-derived extracellular matrix (CDM) system and gauged the effects of eribulin on human pancreatic CAFs and cancer cells. The pathophysiologic cell-culturing system was also used to query eribulin effects on CDM-regulated cancer cell survival and invasive spread. Results demonstrated that intact CDMs modestly restricted eribulin from obstructing cancer cell growth. Nonetheless, eribulin-treated CAFs generated CDMs that limited cancer cell survival under nutritional stress, similar to reported tumor-suppressive CDMs generated by TGF{beta}-deficient CAFs. Data from this study support the central proposed premise and suggest that eribulin could be used as a CAF-normalizing drug.