Low oxygen levels could drive cancer growth

May 3, 2012, University of Georgia

Low oxygen levels in cells may be a primary cause of uncontrollable tumor growth in some cancers, according to a new University of Georgia study. The authors' findings run counter to widely accepted beliefs that genetic mutations are responsible for cancer growth.

If , or low in cells, is proven to be a key driver of certain types of cancer, treatment plans for curing the malignant growth could change in significant ways, said Ying Xu, Regents-Georgia Research Alliance Eminent Scholar and professor of bioinformatics and computational biology in the Franklin College of Arts and Sciences.

The research team analyzed samples of data—also called transcriptomic data—from seven different cancer types in a publicly available database. They found that long-term lack of oxygen in cells may be a key driver of . The study was published in the early online edition of the Journal of Molecular Cell Biology.

Previous studies have linked low oxygen levels in cells as a contributing factor in cancer development, but not as the driving force for cancer growth. High incidence rates of cancer around the world cannot be explained by chance genetic mutations alone, Xu said. He added that bioinformatics, which melds biology and computational science, has allowed researchers to see cancer in a new light. Gene-level mutations may give cancer cells a competitive edge over healthy cells, but the proposed new cancer growth model does not require the presence of common malfunctions such as a sudden proliferation of oncogenes, precursors to cancer cells.

"Cancer drugs try to get to the root—at the molecular level—of a particular mutation, but the cancer often bypasses it," Xu said. "So we think that possibly genetic mutations may not be the main driver of cancer."

Much of cancer research so far has focused on designing drug treatments that counteract associated with a particular type of cancer. In their study, the researchers analyzed data downloaded from the Stanford Microarray Database via a software program to detect abnormal gene expression patterns in seven cancers: breast, kidney, liver, lung, ovary, pancreatic and stomach. The online database allows scientists to examine information from microarray chips, which are small glass slides containing large amounts of gene material.

Xu relied on the gene HIF1A as a biomarker of the amount of molecular oxygen in a cell. All seven cancers showed increasing amounts of HIF1A, indicating decreasing oxygen levels in the cancer cells.

Low oxygen levels in a cell interrupt the activity of oxidative phosphorylation, a term for the highly efficient way that cells normally use to convert food to energy. As oxygen decreases, the cells switch to glycolysis to produce their energy units, called ATP. Glycolysis is a drastically less efficient way to obtain energy, and so the cancer cells must work even harder to obtain even more food, specifically glucose, to survive. When oxygen levels dip dangerously low, angiogenesis, or the process of creating new blood vessels, begins. The new blood vessels provide fresh oxygen, thus improving oxygen levels in the cell and tumor and slowing the cancer growth—but only temporarily.

"When a cancer cell gets more food, it grows; this makes the tumor biomass bigger and even more hypoxic. In turn, the energy-conversion efficiency goes further down, making the cells even more hungry and triggering the cells to get more food from blood circulation, creating a vicious cycle. This could be a key driver of cancer," Xu said.

Xu explained that this new cancer-growth model could help explain why many cancers become drug resistant so quickly—often within three to six months. He stressed the importance of testing the new model through future experimental research. If the model holds, researchers will need to search for methods to prevent hypoxia in cells in the first place, which could result in a sea change in .

Explore further: Scientists identify new mechanism of prostate cancer cell metabolism

Related Stories

Scientists identify new mechanism of prostate cancer cell metabolism

March 22, 2012
Cancer cell metabolism may present a new target for therapy as scientists have uncovered a possible gene that leads to greater growth of prostate cancer cells.

Metabolic state of brain cancer stem cells significantly different than the cancer cells they create

September 6, 2011
The metabolic state of glioma stem cells, which give rise to deadly glioblastomas, is significantly different from that of the brain cancer cells to which they give birth, a factor which helps those stem cells avoid treatment ...

Recommended for you

Study: Cells of three advanced cancers die with drug-like compounds that reverse chemo failure

January 23, 2018
Researchers at Southern Methodist University have discovered three drug-like compounds that successfully reverse chemotherapy failure in three of the most commonly aggressive cancers—ovarian, prostate and breast.

'Hijacker' drives cancer in some patients with high-risk neuroblastoma

January 23, 2018
Researchers have identified mechanisms that drive about 10 percent of high-risk neuroblastoma cases and have used a new approach to show how the cancer genome "hijacks" DNA that regulates other genes. The resulting insights ...

Enzyme inhibitor combined with chemotherapy delays glioblastoma growth

January 23, 2018
In animal experiments, a human-derived glioblastoma significantly regressed when treated with the combination of an experimental enzyme inhibitor and the standard glioblastoma chemotherapy drug, temozolomide.

Scientists block the siren call of two aggressive cancers

January 23, 2018
Aggressive cancers like glioblastoma and metastatic breast cancer have in common a siren call that beckons the bone marrow to send along whatever the tumors need to survive and thrive.

Researchers identify a protein that keeps metastatic breast cancer cells dormant

January 23, 2018
A study headed by ICREA researcher Roger Gomis at the Institute for Research in Biomedicine (IRB Barcelona) has identified the genes involved in the latent asymptomatic state of breast cancer metastases. The work sheds light ...

Boosting cancer therapy with cross-dressed immune cells

January 22, 2018
Researchers at EPFL have created artificial molecules that can help the immune system to recognize and attack cancer tumors. The study is published in Nature Methods.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.