Tel Aviv University Researchers Target Drug-Resistant Ovarian Tumors with Nanotechnology

Tel Aviv University researchers devise a fast and effective nanotechnology — called “gagomers” — to combat drug-resistant ovarian cancer.

Professor Dan Peer of Tel Aviv University’s Department of Cell Research and Immunology has proposed a new strategy to tackle drug-resistant ovarian cancer using a new nanoscale drug-delivery system designed to target specific cancer cells. The study was published in February in the journal ACS Nano.

Nanotechnology usually refers to an object that is 1-to–100 nanometers in size. A nanometer is a billionth of a meter. By comparison, the width of a strand of hair is approximately 100,000 times larger than a nanometer.

Prof. Peer and his team — Keren Cohen and Rafi Emmanuel from Peer’s Laboratory of Nanomedicine and Einat Kisin-Finfer and Doron Shabbat, from TAU’s Department of Chemistry — devised a cluster of nanoparticles called “gagomers,” which are made from fats and coated with a kind of polysugar. When filled with chemotherapy drugs (in this case doxorubicin), these clusters accumulate in tumors, producing dramatic therapeutic benefits.

The objective of Peer’s research is two-fold: to provide a specific target for anti-cancer drugs to increase their therapeutic benefits, and to reduce the toxic side effects of anti-cancer therapies.

Why Chemotherapy Fails

According to Prof. Peer, traditional courses of chemotherapy are not an effective line of attack. Chemotherapy’s failing lies in the inability of the medicine to be absorbed and maintained within the tumor cell long enough to destroy it. In most cases, the chemotherapy drug is almost immediately ejected by the cancer cell, severely damaging the healthy organs that surround it, leaving the tumor cell intact.

Gagomers (labeled in color) accumulating on ovarian cancer cells. (Credit: Image courtesy of American Friends of Tel Aviv University)

Gagomers (labeled in color) accumulating on ovarian cancer cells.
(Credit: Image courtesy of American Friends of Tel Aviv University)

But with this new nanotechnology therapy, Peer and his colleagues saw a 25-fold increase in tumor-accumulated medication and a dramatic dip in toxic accumulation in healthy organs. Tested on laboratory mice, the gagomer affects a change in drug-resistant ovarian cancer tumor cells. Receptors on tumor cells recognize the sugar that encases the gagomer, allowing the binding gagomer to slowly release tiny particles of chemotherapy into the cancerous cell. As more and more of the drug accumulates within the tumor cell, the cancer cells begin to die off within 24-48 hours. In this preclinical setting, the doxorubicin encased gagomers even outperformed pegylated liposomal doxorubicin (Doxil) — a standard of care drug used to treat recurrent ovarian cancer.

“Tumors become resistant very quickly. Following the first, second, and third courses of chemotherapy, the tumors start pumping drugs out of the cells as a survival mechanism,” said Prof. Peer. “Most patients with tumor cells beyond the ovaries relapse and ultimately die due to the development of drug resistance. We wanted to create a safe drug-delivery system, which wouldn’t harm the body’s immune system or organs.”

A Personal Perspective

Prof. Peer chose to tackle ovarian cancer in his research because his mother-in-law passed away at the age of 54 from the disease. “She received all the courses of chemotherapy and survived only a year and a half,” Peer said. “She died from the drug-resistant aggressive tumors.”

“At the end of the day, you want to do something natural, simple, and smart. We are committed to try to combine both laboratory and therapeutic arms to create a less toxic, focused drug that combats aggressive drug-resistant cancerous cells,” said Prof. Peer. “We hope the concept will be harnessed in the next few years in clinical trials on aggressive tumors,” said Prof. Peer.


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