Tumor micro-environment is a rough neighborhood for Nano-particle Cancer Drugs

Nano-particle drugs, tiny containers packed with medicine and with the potential to be shipped straight to tumors, were thought to be a possible silver bullet against cancer. However new cancer drugs based on nano-particles have not improved overall survival rates for cancer patients very much. Scientists at the University of North Carolina at Chapel Hill now think that failure may have less to do with the drugs and tumors than it does the tumor’s immediate surroundings.
“Tumors create bad neighborhoods,” said William Zamboni, the study’s senior author and an associate professor at the UNC Eshelman School of Pharmacy. “They spawn leaky, jumbled blood vessels that are like broken streets, blind alleys and busted sewers. There are vacant lots densely overgrown with collagen fibers. Immune-system cells patrolling the streets might be good guys turned bad, actually working for the tumor. And we’re trying to get a large truckload of medicine through all of that.”
At first, what they saw was no surprise: significantly more of the nano-drug Doxil made it into both triple-negative breast-cancer tumors compared with the standard small-molecule Doxorubicin. “That’s nothing new,” Zamboni said. “We’ve seen that for twenty years.” They also saw the same amount of Doxorubin in both tumors.
What did surprise them was that significantly more of the nano-drug Doxil, twice as much, was delivered to the C3-TAg triple-negative breast cancer tumor than to the T11 triple-negative breast cancer tumor.
 “These tumors are subtypes of a subtype of one kind of cancer and are relatively closely related,” said Zamboni. “If the differences in delivering nanoagents to these two tumors are so significant, we can only imagine what the differences might be between breast cancer and lung cancer.”
 Zamboni and his team suggest that better profiling of tumors and their micro-environments would allow doctors not only to better identify patients who would most benefit from nano-particle-based cancer therapy, but also that clinicians may need to learn more about a patient’s tumor before prescribing treatment with one of the newer nano-particle drugs.
“It looks like the tumor micro-environment could play a big role in cancer treatment,” said Zamboni. “It may be the factor that could point us in the right direction for personalized care not only for triple-negative breast cancer but for any type.”