Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Researchers find how a common genetic mutation makes cancer radiation resistant

Researchers find how a common genetic mutation makes cancer radiation resistant

June 10, 2009

Many cancerous tumors possess a genetic mutation that disables a tumor suppressor called PTEN. Now researchers at Washington University School of Medicine in St. Louis have shown why inactivation of PTEN allows tumors to resist radiation therapy.

The PTEN gene produces a protein found in almost all tissues in the body. This protein acts as a tumor suppressor by preventing cells from growing and dividing too rapidly. Mutations in PTEN are frequently found in prostate cancer and endometrial cancer, melanoma and certain aggressive brain tumors.




Tumors with PTEN mutations are often resistant to radiation therapy, and Tej K. Pandita, Ph.D., a researcher with the Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish Hospital, and his colleagues have been trying to find out why. That information could enable researchers to develop drugs that overcome that resistance and increase the effectiveness of radiation treatments.

In an article to be published July 15, 2009, in the journal Cell Cycle and now available online, they demonstrate that PTEN-deficient cells have defective checkpoints. As cells grow and divide, they pass through several phases. Checkpoints operate during each phase and assess whether a cell is healthy enough to continue growing and dividing. If not - for example, if there is damage to genetic material resulting from radiation treatments - signals from checkpoints should tell the cell to wait until repairs are made or should induce the cell to die.

The finding that checkpoints are affected in PTEN-deficient cells is contrary to some previous research, which had suggested instead that cells with PTEN mutations had defective DNA repair mechanisms. But Pandita showed that DNA repair is independent of PTEN function in tumor cells grown in the laboratory. That indicated that defective DNA repair is not the cause of the unstable genomes frequently seen in PTEN-deficient tumor cells and not the explanation for radiation resistance in these tumors.

"The defective checkpoints contribute to radioresistance," says Pandita, associate professor of radiation oncology and of genetics. "When a cell gets damaged by radiation, normally checkpoints will make it stop growing to repair the damage. If the checkpoints are working but the cell has a defective DNA repair system, the cell will be radiosensitive. But if the checkpoints don't operate, the cell can bypass DNA repair and continue to grow and divide. Then the cells are radioresistant."

The results indicate that to increase radiation sensitivity in tumors with PTEN mutations it will be necessary to develop drugs that correct for the faulty checkpoint processes, Pandita says. Work continues in the laboratory to further unravel the details of the checkpoint system and its role in radiation therapy resistance.



Washington University in St. Louis



Related Radiation Therapy Current Events and Radiation Therapy News Articles Radiation Therapy Current Events and Radiation Therapy News RSS Radiation Therapy Current Events and Radiation Therapy News RSS
Rare pancreatic cancer patients may live longer when treated with radiation therapy
Radiation therapy is effective in achieving local control and palliation in patients with pancreatic neuroendocrine tumors (PNTs), despite such tumors being commonly considered resistant to radiation therapy.

New cancer target for non-Hodgkin's lymphoma
Physician-scientists from Weill Cornell Medical College have discovered a molecular mechanism that may prove to be a powerful target for the treatment of non-Hodgkin's lymphoma, a type of cancer that affects lymphocytes, or white blood cells.

Iowa State engineers develop 3-D software to give doctors, students a view inside the body
James Oliver picked up an Xbox game controller, looked up to a video screen and used the device's buttons and joystick to fly through a patient's chest cavity for an up-close look at the bottom of the heart.

Men leave: Separation and divorce far more common when the wife is the patient
A woman is six times more likely to be separated or divorced soon after a diagnosis of cancer or multiple sclerosis than if a man in the relationship is the patient, according to a study that examined the role gender played in so-called "partner abandonment." The study also found that the longer the marriage the more likely it would remain intact.

PET imaging response a prognostic factor after thoracic radiation therapy for lung cancer
A rapid decline in metabolic activity on a PET scan after radiation therapy for non-small cell lung cancer is correlated with good local tumor control, according to a study presented by researchers at Thomas Jefferson University Hospital at the 51st ASTRO Annual Meeting.

Chemo-radiation before prostate removal may prevent cancer recurrence
Researchers in the Oregon Health & Science University Knight Cancer Institute and the Portland Veterans Affairs Medical Center have found a combination of radiation therapy and chemotherapy given before prostate removal is safe and may have the potential to reduce cancer recurrence and improve patient survival.

Radiation therapy technique successfully treats pain in patients with advanced cancer
Stereotactic radiosurgery (SRS), a radiation therapy procedure pioneered at the University of Pittsburgh Cancer Institute (UPCI) that precisely delivers a large dose of radiation to tumors, effectively controls pain in patients with cancer that has spread to the spine.

Aiming to avoid damage to neurocognitive areas of the brain during cranial radiation
Radiation oncologists at Rush University Medical Center are intent on finding ways to avoid damage to the critically important hippocampus and limbic circuit of the brain when cranial radiation is required to treat existing or potential metastatic cancers.

Study of concurrent radiotherapy, chemotherapy shows promise in small cell lung cancer
Treating limited stage small cell lung cancer(LSCL) with a combination of accelerated high-dose radiotherapy and chemotherapy has shown encouraging results.

Stereotactic radiotherapy offers noninvasive, effective treatment for frail patients with early-stage lung cancer
Stereotactic body radiation therapy (SBRT) should be considered a new standard of care for early-stage lung cancer treatment in patients with co-existing medical problems, according to results from a national clinical trial led by UT Southwestern Medical Center physicians.
More Radiation Therapy Current Events and Radiation Therapy News Articles
Principles and Practice of Radiation Therapy

Principles and Practice of Radiation Therapy
by Charles M. Washington MBA RT(T) FASRT (Author), Dennis T. Leaver MS RT(R)(T) FASRT (Author)

Learn everything you need to know about radiation therapy with the only comprehensive text written for radiation therapy students by radiation therapists. Principles and Practice of Radiation Therapy is designed to help you understand cancer management, improve clinical techniques for delivering doses of radiation, and apply complex concepts to treatment planning and delivery. This edition features enhanced learning tools and thoroughly updated content, including three new chapters to inform you of increasingly important technologies and practices. The up-to-date and authoritative coverage of this text make it a resource you'll want to consult throughout your radiation therapy courses and beyond.

Complete coverage of radiation therapy provides all introductory content plus the full...

The Physics of Radiation Therapy

The Physics of Radiation Therapy
by Faiz M Khan (Author)

Dr. Khan's classic textbook on radiation oncology physics is now in its thoroughly revised and updated Fourth Edition. It provides the entire radiation therapy team--radiation oncologists, medical physicists, dosimetrists, and radiation therapists--with a thorough understanding of the physics and practical clinical applications of advanced radiation therapy technologies, including 3D-CRT, stereotactic radiotherapy, HDR, IMRT, IGRT, and proton beam therapy. These technologies are discussed along with the physical concepts underlying treatment planning, treatment delivery, and dosimetry. This Fourth Edition includes brand-new chapters on image-guided radiation therapy (IGRT) and proton beam therapy. Other chapters have been revised to incorporate the most recent developments in the field....

Radx Radiation Therapy Moisture Therapy Cream, 2 oz.

Radx Radiation Therapy Moisture Therapy Cream, 2 oz.
by SolRx

Get relief from the effects of radiation therapy with the Radx line of non-prescription skin care products from SolRx. They have been tested in several hundred cancer treatment facilities throughout the United States with exceptional results. The moisture therapy cream contains Prickly Pear Cactus gel and reduces the damaging effects of radiation when used before treatments as well as replenishing lost moisture when used after treatments.

Essential Oil - Radiation Therapy Wellness Oil - 2 Ounces - Certified Organic - Made in USA

Essential Oil - Radiation Therapy Wellness Oil - 2 Ounces - Certified Organic - Made in USA
by NI

There's nothing fun about going through radiation. We've created this formula with your physical and mental wellbeing in mind. Physically, lavender has powerful healing properties for burn victims. In fact, aromatherapy was founded on this very concept! Mentally, lavender essential oil can be calming and uplifting at the same time. It is our hope that you find some calm as you heal physically while using this oil. While generally regarded as safe during pregnancy, it's is always a good idea to check with your doctor before using any product. Safe to use on children over the age of two years .

Halloween

Halloween
radiation therapy (Primary Contributor)



Non-Small Cell Lung Cancer: New Therapies (Home Use)

Non-Small Cell Lung Cancer: New Therapies (Home Use)

Lung cancer is the leading cancer killer among men and women alike, claiming more lives than breast, colon and prostate cancer combined. Non-small cell lung cancer is the most common type of this disease, accounting for 87 percent of all lung cancers. Because lung cancer has usually spread throughout the body before it is discovered, the survival rates for patients are quite poor. But new therapies and advances in imaging studies that could lead to earlier detection are serving as beacons of hope for patients and their families. This program is part of the award winning public television series Healthy Body, Healthy Mind.

This product is manufactured on demand using DVD-R recordable media. Amazon.com's standard return policy will apply.



Radiation Therapy Planning

Radiation Therapy Planning
by Gunilla Bentel (Author)

All new expanded edition provides step-by-step guidelines on performing the technical aspects of radiation therapy. Important new coverage includes treatment preparation, 3-D treatment planning, dosimetry, new technologies, documentation, and quality assurance. In addition, you'll find added treatment planning guidelines by body region, and an expanded art program including many new 4-color illustrations.

Radiation Therapy:"What to Expect" Breast Cancer [VHS]

Radiation Therapy:"What to Expect" Breast Cancer [VHS]
Starring: Robin Conover, St. Peter's Hospital Radiation Therapy Department Staff, Jerry Martinez
Directed By: Robin Conover, Jerry Martinez

This top national "Communicator Award of Excellence" winning video is an extremely valuable tool for newly diagnosed women with breast cancer. The video are for those who are considering or about to start radiation therapy treatments. This video will:

Clearly show you what radiation therapy is and how it works

Give you answers to the most commonly asked questions

Tell you about the possible side effects

Help reduce any anxiety about receiving radiation therapy

Make your radiation therapy experience much easier

DosimetryTables for Radiation Therapy

DosimetryTables for Radiation Therapy
by JB Software

Radiation Dosimetry Tables

Nature's Inventory Radiation Therapy Wellness Oil (Pack of 2)

Nature's Inventory Radiation Therapy Wellness Oil (Pack of 2)
by Nature's Inventory

We created this oil together for a friend that was getting radiation for breast cancer. She called after day 26 to let us know that the doctors couldn't believe how well her skin looked! She told them what she was doing and the doctor told her "good for y

© 2009 BrightSurf.com