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Washington, April 6 (ANI): An Indian-origin scientist at the University of Pennsylvania School of Medicine and his colleagues have found a way to turn an adaptive cellular response into a liability for cancer cells.

When normal cells are starved for food, they chew up existing proteins and membranes to stay alive.

Cancer cells have corrupted that process, called autophagy, using it to survive when they run out of nutrients and to evade death after damage from chemotherapy and other sources.

When the Penn researchers treated a group of patients with several different types of advanced cancers with temsirolimus, a molecularly targeted cancer drug that blocks nutrient uptake, plus hydroxychloroquine, an anti-malarial drug that inhibits autophagy, they saw that tumours stopped growing in two-thirds of the patients.

“The results are very encouraging — striking, even,” said senior author Ravi Amaravadi.

“Temsirolimus by itself has little effect in this patient population. Tumors laugh at it, with response percentages of just zero to 5 percent. But by combining it with hydroxychloroquine, we found that 14 out of 21 patients had stable disease after treatment, including five out of six melanoma patients,” he added.

In addition to melanoma, patients involved in the study also had colorectal, head and neck, breast, gastro-esophageal, prostate, pancreatic, lung and adrenal cancers.

The patients showed substantial rates of disease stabilization with the treatment combination and side effects observed were relatively limited.

Amaravadi’s team was able to see evidence of autophagy inhibition in peripheral blood cells in patients treated with the combination. And the inhibition increased with increasing doses of hydroxychloroquine, suggesting that the drug is working as they hypothesized it would.

The researchers note that the relatively limited side effect profile of the novel temsirolimus-hydroxychloroquine combination suggested researchers might be able to layer other therapies on top of it, making the combination an even more powerful treatment.

They have presented the data at the American Association for Cancer Research 102nd Annual Meeting 2011 in Orlando on Tuesday. (ANI)