About My Health Careers Internship MedBlogs Contact us
Medindia LOGIN REGISTER
Advertisement

Cell Cycle-blocking Drugs Can Shrink Tumor Cells

by Hannah Joy on August 21, 2017 at 12:02 PM
Font : A-A+

Cell Cycle-blocking Drugs Can Shrink Tumor Cells

Drugs known as CDK4/6 inhibitors have been approved for treating metastatic breast cancer. In certain patients, it was found that these drugs not only stop the growth of the tumor, but can also shrink the cells, reveals a new study.

New research by scientists at Dana-Farber Cancer Institute (Dana-Farber) and Brigham and Women's Hospital (BWH) reveals an unexpected mechanism behind these tumor regressions.

Advertisement


In a study published online by the journal Nature, the investigators show that CDK4/6 inhibitors not only stymie the division of cancer cells but can also spur the immune system to attack and kill the cells. When the drugs were coupled with other immunotherapy agents, the anti-cancer effect can be even greater, they report.

The findings, which follow Dana-Farber scientists' recent discovery that CDK4/6 inhibitors can slow the growth of cancer cells carrying a surplus of a certain protein, suggest that the drugs' potential in cancer treatment has only begun to be tapped. If their effectiveness increases in combination with immunotherapies, as early evidence indicates, that potential may be greater than is even now apparent.
Advertisement

"The CDK4 and 6 proteins are critical drivers of the cell-division cycle and are required for the formation and growth of various types of solid tumors," says Dana-Farber's Shom Goel, MD, PhD, co-first author of the study with Molly DeCristo of the Hematology Division at BWH.

"Agents that block the proteins - CDK4/6 inhibitors have received Food and Drug administration approval for some patients with metastatic breast cancer, but they've also shown promise against others types of tumors in clinical trials. In early clinical trials of these drugs, we noticed that in some breast cancer patients the tumors didn't just remain the same size -- as would be expected with drugs that interfere with cell division -- but began to recede, sometimes quite dramatically, said Goel."

To understand why this occurs, they examined the effect of a CDK4/6 inhibitor called abemaciclib in mice with breast or other solid tumors. They found the agent not only stalled the tumor cell cycle but also caused the immune system to mount an attack on the tumors. They confirmed the finding by analyzing tissue samples from women participating in a clinical trial of a CDK4/6 inhibitor for breast cancer.

The drugs trigger an anti-tumor immune response in two ways, the researchers discovered. In cancer cells, the drugs produce a substantial increase in the display of abnormal proteins on the cells' surface. These proteins, called antigens, serve as a signal to the immune system that a diseased or cancerous cell is present and needs to be eliminated.

At the same time, the drugs can spark a reduction in immune system cells known as T regulatory cells (Tregs), which usually tamp down the immune response to disease or infection. Fewer Tregs results in a fiercer immune system attack. The cumulative effect of these processes is a halting or reversal of tumor growth.

"The anti-tumor immune response with CDK4/6 inhibition was somewhat unexpected -- some had previously thought that CDK4/6 inhibitors would block anti-tumor immunity, due to effects on T cell proliferation, but our findings demonstrate quite the opposite," DeCristo states.

"This surprising finding opens the door for combining immunotherapy with CDK4/6 inhibitors."

In clinical trials, about 20 percent of breast cancer patients treated with abemaciclib by itself have a significant response to the drug and another 20 to 30 percent have stabilizations of tumor growth, the authors explained. The responses have tended to appear within four months of starting the therapy, they added.

In the current research, even better results have been obtained in mice when the drugs are used in combination with immunotherapy agents known as checkpoint inhibitors, which can foil cancer's ability to evade an immune system attack.

"It appears that the CDK4/6 inhibitors might be able to sensitize some patients' cancers to the anti-tumor effects of immune checkpoint inhibitors," the authors state. "The result might be especially encouraging for breast cancer patients, who have derived little benefit from immunotherapy in trials conducted to date."

Further research is needed to understand why some patients receive the full spectrum of benefits from CDK4/6 inhibitors while others don't, and to seek ways to expand these benefits to more patients.

The results also should spur future studies of combined regimens of CDK4/6 inhibitors and different types of immunotherapy, the authors state.



Source: Eurekalert
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Advertisement
News Category
What's New on Medindia
Menstrual Disorders
Coffee May Help You Fight Endometrial Cancer
Fermented Skin Care
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
Drug Toxicity Parkinsons Disease Surgical Treatment Tumor Markers For Cancer Diagnosis and Prognosis Drugs Banned in India 

Recommended Reading
Cancer Immunotherapy
Cancer immunotherapy is a new advancement in cancer treatment that uses certain components of a ......
Allergy
An allergy is a hypersensitive disorder of immune system. Substances that often cause allergic ......
Novel Genetic Screening a Boon to Cancer Immunotherapy
A CRISPR-Cas9 screening system was developed to identify new gene targets for cancer immunotherapy....
Drug Toxicity
Drug toxicity is an adverse reaction of the body towards a drug that results as a side effect of a d...
Drugs Banned in India
Several drugs are either banned or withdrawn after introduction in the market....
Tumor Markers For Cancer Diagnosis and Prognosis
An ideal tumor marker for a cancer should be specific to that cancer and not generate false positive...

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2022

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use
open close
ASK A DOCTOR ONLINE
I have read and I do accept terms of use - Telemedicine

Advantage Medindia: FREE subscription for 'Personalised Health & Wellness website with consultation' (Value Rs.300/-)