How cells decide to grow, age, or respond to a drug

I study one question from a few angles: how does a cell decide what to do next? It can keep dividing, stop for good, wear out with age, or respond to a drug. This note explains the parts of that question I have worked on, and where the work is going.

Aging: why cells wear out

For my PhD at Concordia, I studied aging in yeast. Yeast cells age in ways that are surprisingly close to ours, and they let you test an idea in days rather than years. Why yeast is the best aging model explains why.

We screened plant extracts for ones that help yeast live longer, and found several. The strongest came from white willow bark. We called it PE21, and we showed that it delays aging by changing how cells handle fats (lipids).

Cancer: cells that don't stop

As a postdoc at the Goodman Cancer Institute at McGill University, I turned to the opposite problem: cells that keep dividing when they should stop.

I studied triple-negative breast cancer, a form that lacks the three receptors most targeted drugs act on. We found that three proteins, PML, mTOR and RONIN, work together to turn down the genes that build ribosomes, the cell's protein factories. When that happens, the cancer cells stop dividing and enter a permanent resting state called senescence.

I also worked on mutations in a protein called ERRα in a rare form of breast cancer, and on FBXW7, a protein in liver cells that controls how the body handles nutrients and fat.

Delivery: the right molecule to the right cell

Knowing what controls a cell only helps if a treatment can reach that cell. Many drugs work in a dish but damage healthy tissue in the body, which limits the dose a patient can take.

Today, I work on extracellular vesicles (EVs), small particles that cells release naturally to exchange proteins and RNA. Because the body already makes and reads them, they could carry a drug to its target in a form the body accepts. I develop two carriers: one carries a chemotherapy drug, and ProbioVesicle, made from probiotic yeast, which carries anti-aging ingredients. I also test how the human immune system responds to them, because a carrier the body attacks is not a useful carrier.

Where this is going

These are early results. A carrier that works on cells in a dish still has to be tested in animals and, later, in people. The goal is a therapy, and the path there is long. Each step needs the same care: understand the mechanism, test it in more than one model, and check that the body accepts the treatment.

You can read more on the research page and in my notes on aging, cancer and drug delivery.