MedicineWorld.Org
Your gateway to the world of medicine
Home
News
Cancer News
About Us
Cancer
Health Professionals
Patients and public
Contact Us
Disclaimer

Medicineworld.org: Environmental stress and cancer

Back to cancer blog Blogs list Cancer blog  


Subscribe To Cancer Blog RSS Feed  RSS content feed What is RSS feed?

Environmental stress and cancer




One way environmental stress causes cancer is by reducing the activity level of an enzyme that causes cell death, scientists say.

They observed that stress-inducing agents, such as oxidative stress, recruit a protein called SENP1 that cuts a regulator called SUMO1 away from the enzyme SIRT1 so its activity level drops, says Dr. Yonghua Yang, postdoctoral fellow in the laboratory of Dr. Kapil Bhalla, director of the MCG Cancer Center.

This fundamental finding about the relationship between stress and cancer opens the door for therapys that increase SENP1 activity, making it easier for cells that are becoming malignant to die, says Dr. Yang, first author on a paper reported in the recent issue of Nature Cell Biology.



Environmental stress and cancer
Drs. Kapil Bhalla (left) and Yonghua Yang.

Credit: Medical College of Georgia

This is one of the things that makes cancer cells so durable, one way they survive so well, says Dr. Yang. We want to see if we can block that process and make cells die. Increased SIRT1 activity which is routinely present in cancer even makes cancer cells more resistant to anticancer drugs such as chemotherapy.

The complication is that decreasing programmed cell death, or apoptosis, increases longevity, says Dr. Yang. However he now has evidence that SIRT1 also under study for its longevity role has different targets when it comes to cancer promotion and longevity that will provide distinct targets for manipulating each.

Whether apoptosis is good or bad depends on the circumstances, says Dr. Yang. But its good for cancer treatment.

This paper describes how stress causes desumoylation and sumoylation of SIRT1 and ultimately cancer, says Dr. Bhalla, Cecil F. Whitaker Jr., M.D./Georgia Research Alliance Eminent Scholar in Cancer and a co-author of study.

Stress-inducing agents produce the association of this enzyme,SIRT-1, with the desumoylating enzyme, SENP1, so cells become more resistant to stress-induced apoptosis, says Dr. Bhalla. Once SIRT1 is desumoylated, its less active and you want its activity. When SIRT1 is less active, p53, a tumor suppressor gene that also causes apoptosis, becomes more active.

SIRT1, found throughout the body, is a regulator of protein function through a process called acetylation. MCG scientists also observed that sumoylation of SIRT1 (combining it with SUMO1) made it more active and sumoylation motif, which enables SUMO1 to combine with SIRT1, is needed to make that happen.

They have added SUMO1 to human cancer cells and increased SIRT1 activity then used SENP1 to cleave it and reduce activity.

Scientists studying the longevity benefits of SIRT1 have found conflicting information in yeast and mice about whether or not SIRT1 is of benefit. Dr. Yang may have found one reason: mice SIRT1 doesnt contain sumoylation motif. When he created sumoylation motif in mice, SIRT1 activity went up. Dr. Yang will do follow up studies to see if these mice live longer but says SIRT1 may simply have a different function in mice than in humans or yeast, also a common research model.


Posted by: Janet    Source




Did you know?
One way environmental stress causes cancer is by reducing the activity level of an enzyme that causes cell death, scientists say. They observed that stress-inducing agents, such as oxidative stress, recruit a protein called SENP1 that cuts a regulator called SUMO1 away from the enzyme SIRT1 so its activity level drops, says Dr. Yonghua Yang, postdoctoral fellow in the laboratory of Dr. Kapil Bhalla, director of the MCG Cancer Center.

Medicineworld.org: Environmental stress and cancer

Main Page| Cancer blog| Cancer blogs list| Lung cancer blog| Colon cancer blog| Prostate cancer blog| Breast cancer blog| Diabetes watch blog| Heart watch blog| Allergy blog| Bladder cancer blog| Cervical cancer blog| Colon cancer news blog| Diabetes news blog| Esophageal cancer blog| Gastric cancer blog| Health news blog| Heart news blog| Infectious disease blog| Kidney watch blog| Lung disease blog| Lung cancer news blog| Mesothelioma blog| Neurology blog| Breast cancer news blog| OBGYN blog| Ophthalmology blog| Ovarian cancer blog| Cancer news blog| Pancreas cancer blog| Pediatrics blog| Prostate cancer news blog| Psychology blog| Research blog| Rheumatology blog| Society news blog| Uterine cancer blog| Weight watch blog|

Copyright statement
The contents of this web page are protected. Legal action may follow for reproduction of materials without permission.