Photodynamic Therapy Advances Offers New Ovarian Cancer Approach

Photodynamic Therapy Advances Offers New Ovarian Cancer Approach
Researchers have made a significant advance in the use of photodynamic therapy to combat ovarian cancer in laboratory animals, using a combination of techniques that achieved complete cancer cell elimination with no regrowth of tumors.
The findings were just published in the journal Nanomedicine: Nanotechnology, Biology and Medicine, and after further research may offer a novel mechanism to address this aggressive and often fatal cancer.
Ovarian cancer has a high mortality rate because it often has metastasized into the abdominal cavity before it's discovered. Toxicity and cancer-cell resistance can also compromise the effectiveness of radiation and chemotherapy that's often used as a follow-up to surgery.
The new approach makes photodynamic therapy significantly more effective by adding compounds that make cancer cells vulnerable to reactive oxygen species, and also reducing the natural defenses of those cells.
Using the new approach, a patient is first given a photosensitizing compound called phthalocyanine, which produces reactive oxygen species that can kill cells when they are exposed to near-infrared light. In addition, a gene therapy is administered that lowers the cellular defense against reactive oxygen species.
Both the phthalocyanine and genetic therapy, composed of "small, interfering RNA," are attached to what researchers call "dendrimer-based nanoplatforms," a nanotechnology approach. It delivers the compounds selectively into cancer cells, but not healthy cells.
Compared to existing photodynamic therapies, this approach allows the near-infrared light to penetrate much deeper into abdominal tissues, and dramatically increases the effectiveness of the procedure in killing cancer cells.
Using photodynamic therapy alone, some tumors in laboratory animals began to regrow after two weeks. But with the addition of the combinatorial genetic therapy to weaken the cancer cell defenses, there was no evidence of cancer recurrence. During the procedures, mice receiving the gene therapy also continued to grow and gain weight, indicating a lack of side effects.
"Our study established a prospective therapeutic approach against ovarian cancer," the researchers wrote in their conclusion. "The tumors exposed to a single dose of a combinatorial therapy were completely eradicated from the mice."
Based on material originally posted by Oregon State University.