Some researchers argue that there may be a direct link between having diabetes and exposure to an increased risk of metastasis in cancer. New research validates this idea, explaining how diabetes can elevate this risk.
Hundreds of millions of people across the globe live with one form of diabetes, which makes this one of the most common health conditions that doctors diagnose.
People with diabetes tend to have a higher risk of developing certain additional medical conditions, including problems with eyesight, heart disease, and other cardiovascular problems.
Now, emerging evidence also suggests that diabetes could elevate the risk of tumors metastasizing — or spreading — in cancer.
Recently, a team of researchers from Cornell University in Ithaca, NY, has explored the potential mechanisms underlying the relationship between diabetes and metastatic cancer.
"Cancer and diabetes are two of the worst health problems in developed countries, and there's a link between the two," says study author Prof. Mingming Wu.
"For cancer, half of the story is still in genetics. It's only recently we realized there is another half that we missed, which is the microenvironment," Prof. Wu adds.
In other words, the growth and spread of cancer might be highly dependent on the biological environment that surrounds it, and diabetes, the researchers believe, may create the right setting to increase the motility (ability to move) of cancer cells.
'Glycation boosts the rate of metastasizing'
Metastasis — or cancer spread — occurs when cancer cells are able to "travel" from the site of primary tumors towards other parts of the body, eventually giving rise to new tumors.
To get from the site of a primary tumor to elsewhere in the body, cancer cells must navigate the extracellular matrix, a network that provides support and structure to the cells of the body. Different types of macromolecules, which include collagen and glycoproteins, make up this matrix.
Prof. Wu and colleagues explain that elevated blood sugar in people with diabetes can impact the structure of the collagen fibers in a way that makes it easier for cancer cells to move around.
The changes to collagen fibers occur through a process called "glycation," a reaction between sugars and proteins or other biological compounds.
"[People with diabetes] have higher blood sugar levels, which lead to glycation and changes the structure of the collagen in their tissue," explains the study's lead author, Young Joon Suh, who is currently a graduate student at Cornell.
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"If they happen to have cancer, we believe this glycation process promotes the rate of metastasizing."
Young Joon Suh
In their study — the results of which appear in the journal Integrative Biology — the researchers tested this mechanism by looking at how cancer cells from breast cancer tumors fared in environments with different levels of glycation.
Their experiments revealed that the cells had increased motility — that is, they were able to move around at faster rates, and also to "travel" farther away from the original site — when their environment had high glycation.
In fact, the team explains that the average speed of movement of breast cancer cells was higher in all three types of collagen environments that they used — when they were glycated.
These findings, the researchers believe, indicate that the conditions that diabetes creates in the body may indeed increase a person's risk of metastasis if they have cancer.
Going forward, the scientists aim to further distinguish between the mechanical and chemical impact of glycation on the process of metastasis.
"Future work will be needed to elucidate the biochemical impact of glycation in tumor cell invasion," the researchers write.