Tag Archives: chemotherapy

Chemotherapy may “help” Cancer grow!

Chemotherapy can backfire and boost cancer growth: study
AFPAFP –

Cancer-busting chemotherapy can cause damage to healthy cells which triggers them to secrete a protein that sustains tumour growth and resistance to further treatment, a study said Sunday.

Researchers in the United States made the “completely unexpected” finding while seeking to explain why cancer cells are so resilient inside the human body when they are easy to kill in the lab.

They tested the effects of a type of chemotherapy on tissue collected from men with prostate cancer, and found “evidence of DNA damage” in healthy cells after treatment, the scientists wrote in Nature Medicine.

Chemotherapy works by inhibiting reproduction of fast-dividing cells such as those found in tumours.

The scientists found that healthy cells damaged by chemotherapy secreted more of a protein called WNT16B which boosts cancer cell survival.

“The increase in WNT16B was completely unexpected,” study co-author Peter Nelson of the Fred Hutchinson Cancer Research Center in Seattle told AFP.

The protein was taken up by tumour cells neighbouring the damaged cells.

“WNT16B, when secreted, would interact with nearby tumour cells and cause them to grow, invade, and importantly, resist subsequent therapy,” said Nelson.

In cancer treatment, tumours often respond well initially, followed by rapid regrowth and then resistance to further chemotherapy.

Rates of tumour cell reproduction have been shown to accelerate between treatments.

“Our results indicate that damage responses in benign cells… may directly contribute to enhanced tumour growth kinetics,” wrote the team.

The researchers said they confirmed their findings with breast and ovarian cancer tumours.

The result paves the way for research into new, improved treatment, said Nelson.

“For example, an antibody to WNT16B, given with chemotherapy, may improve responses (kill more tumour cells),” he said in an email exchange.

“Alternatively, it may be possible to use smaller, less toxic doses of therapy.”

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Chemotherapy Cuts Lung Cancer Tumor in Half……Correction – Marijuana cuts Cancer Growth in HALF

Marijuana Cuts Lung Cancer Tumor Growth In Half, Study Shows

WAR ON DRUGS

They say this is the first set of experiments to show that the compound, Delta-tetrahydrocannabinol (THC), inhibits EGF-induced growth and migration in epidermal growth factor receptor (EGFR) expressing non-small cell lung cancer cell lines. Lung cancers that over-express EGFR are usually highly aggressive and resistant to chemotherapy.

THC that targets cannabinoid receptors CB1 and CB2 is similar in function to endocannabinoids, which are cannabinoids that are naturally produced in the body and activate these receptors. The researchers suggest that THC or other designer agents that activate these receptors might be used in a targeted fashion to treat lung cancer.

“The beauty of this study is that we are showing that a substance of abuse, if used prudently, may offer a new road to therapy against lung cancer,” said Anju Preet, Ph.D., a researcher in the Division of Experimental Medicine.

Acting through cannabinoid receptors CB1 and CB2, endocannabinoids (as well as THC) are thought to play a role in variety of biological functions, including pain and anxiety control, and inflammation. Although a medical derivative of THC, known as Marinol, has been approved for use as an appetite stimulant for cancer patients, and a small number of U.S. states allow use of medical marijuana to treat the same side effect, few studies have shown that THC might have anti-tumor activity, Preet says. The only clinical trial testing THC as a treatment against cancer growth was a recently completed British pilot study in human glioblastoma.

In the present study, the researchers first demonstrated that two different lung cancer cell lines as well as patient lung tumor samples express CB1 and CB2, and that non-toxic doses of THC inhibited growth and spread in the cell lines. “When the cells are pretreated with THC, they have less EGFR stimulated invasion as measured by various in-vitro assays,” Preet said.

Then, for three weeks, researchers injected standard doses of THC into mice that had been implanted with human lung cancer cells, and found that tumors were reduced in size and weight by about 50 percent in treated animals compared to a control group. There was also about a 60 percent reduction in cancer lesions on the lungs in these mice as well as a significant reduction in protein markers associated with cancer progression, Preet says.

Although the researchers do not know why THC inhibits tumor growth, they say the substance could be activating molecules that arrest the cell cycle. They speculate that THC may also interfere with angiogenesis and vascularization, which promotes cancer growth.

Preet says much work is needed to clarify the pathway by which THC functions, and cautions that some animal studies have shown that THC can stimulate some cancers. “THC offers some promise, but we have a long way to go before we know what its potential is,” she said.

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