Switching To A Low-Protein Diet Makes Cancer Cells Starve, Betters Fighting Chance: Study

Altering the diet could be helpful in taking down colon cancer, reveals a new study conducted by researchers from University of Michigan Rogel Cancer Centre, reported by Science Daily.

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Cancer cells, much like human cells, need nutrients to grow. And one most crucial nutrient-sensing molecule in a cell is dubbed mTORC1. Regarded as the master regulator of cell growth, it allows cells to sense different nutrients and help them grow and expand.

When the nutrients aren¡¯t enough, cells reduce the intensity of looking for nutrients, turning off mTORC1 along the way.

Even though mTORC1 is regarded to be hyperactive in colon cancer, the biggest concern is whether colon tumours take control over nutrient-sensing pathways to force mTORC1 to go into overdrive.

Senior author Yatrik M. Shah, PhD, Horace W. Davenport Collegiate Professor of Physiology at Michigan Medicine explains that in the case of colon cancer, when the cells see there aren¡¯t enough nutrients available, they go into a crisis state as they don¡¯t really know what to do, resulting in massive cell death.

Researchers found in cells and in mice that a low-protein diet blocked the nutrient signalling pathway that started the master regulator (mTORC1) responsible for cancer growth.

mTORC1 is known to control how cells should use nutritional signals to grow and multiply. It¡¯s seen to be very active in cancers with some mutations, and it can also become resistant to standard treatments.

Researchers, however, were able to alter the nutritional signals by shifting to a low-protein diet and specific reduction in two key amino acids, through a complex dubbed GATOR.

GATOR1 and GATOR2 worked in tandem to keep mTORC1 active. When a cell had plenty of nutrients, GATOR2 activated mTORC1. When the nutrients became low, GATOR1 deactivated mTORC1. Additionally, limiting some kinds of amino acids help in blocking nutrient signalling.

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There have been previous attempts at blocking mTORC with the help of inhibitors but they've had severe side effects and when the patients stop taking them, cancer would bounce back. The new method involving blocking the pathway with the help of limiting amino acids through a low-protein diet offers an alternative way to shut down mTORC.

Study first author Sumeet Solanki, PhD, a research investigator at the Rogel Cancer Center, explained, "We knew that nutrients were important in mTORC regulation but we didn't know how they directly signal to mTORC. We discovered the nutrient signalling pathway is just as important to regulate mTORC as the oncogenic signalling pathway."

Shah further added, "Putting cancer patients on a protein-deficient diet long-term is not ideal. But if you can find key windows -- like at the start of chemotherapy or radiation -- when patients could go on a low protein diet for a week or two, we could potentially increase the efficacy of those treatments."