How Hungry Fat Cells Could Someday Starve Cancer to Death

Scientists transformed energy-storing white fat cells into calorie-burning ‘beige’ fat. Once implanted, they outcompeted tumors for resources, beating back five different types of cancer in lab experiments.

Urothelial carcinoma (UC) is the second most common genitourinary cancer, leading to over 16,000 deaths a year in the U.S. Despite recent advances, the five-year survival rate for metastatic UC remains around 5% to 10%. 

The first FDA-approved antibody-drug conjugate therapy for metastatic UC (mUC), enfortumab vedotin (EV), targets NECTIN4, a protein that is expressed on the cell surface of bladder cancer cells, and is now the frontline, standard of care treatment for patients with advanced urothelial carcinoma in the U.S. While EV monotherapy leads to at least a 40% response rate in most patients with mUC, in patients whose malignancy is treatment resistant, meaningful improvement in long-term remissions and overall survival are rare. 

To improve treatment rates for these patients, UCSF researchers designed a CAR T cell therapy and combined it with an older class of diabetes drugs called thiazolidinediones, to enhance NECTIN4 expression and make tumor cells more susceptible to NECTIN4-CAR T therapy.

Their research appears Sept.10 in Nature Communications.

“We sought to understand how cancer cells regulated expression of NECTIN4, and whether we could leverage that information to enhance NECTIN4 expression and increase the efficacy of the CAR T therapy,” said study senior author Jonathan Chou, MD, PhD, assistant professor in the UCSF Division of Hematology/Oncology. “We found that a pathway that controls fat metabolism, called PPAR gamma, facilitates NECTIN4 expression. Interestingly, we repurposed older diabetes drugs, including rosiglitazone and pioglitazone, both of which stimulate PPAR gamma to enhance NECTIN4 expression.”

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