When there is a malignant tumor, it can grow until tumor cells travel to other areas of the body through the lymphatic system, where they can proliferate and form a new tumor. This process is called metastasis, and when it occurs, the chances of overcoming cancer are greatly reduced. Therefore, it is vital to identify evidence of metastasis in tumors before it occurs.
Now, the results of an investigation published in the scientific journal Oncogene could give the opportunity to stop the metastasis , identifying it long before it develops.
Scientists have discovered that the protein called LTBP3 sets off a chain reaction that leads primary tumors to develop new blood vessels. The intervention of this protein is vital, since the new blood vessels are the ones that act as a “highway” for tumor cells to move to other areas of the body.
That is, this protein is responsible for preparing the way for metastasis to occur , a process called angiogenesis.
Therefore, identifying high levels of this protein in tumor tissues is a probable sign of metastasis, allowing medicine to anticipate this phenomenon long before it occurs.
“Lower levels of LTBP3 appear to be associated with a better prognosis in patients with certain types of cancer,” according to Dr. Elena Deryugina, lead author of the study.
On the left, the robust network of fully dilated angiogenic blood vessels (in red) within a primary tumor, which developed from LTBP3 competent squamous cell carcinoma cells (green). On the right, in contrast, LTBP3-deficient tumors develop thinner collapsed vessels, which are unable to effectively support the spread of cancer cells. / Elena Deryugina and James P. Quigley.
The research, in fact, addresses a long-standing challenge in medicine. Over the years, a growth factor molecule, called TGFβ, has caught the attention of many cancer researchers.
TGFβ fulfills multiple functions, not only in tumor cells, but also in healthy tissues. It can be both a promoter and a suppressor of tumor cell growth. Although TGFβ has long been a tempting target for cancer therapy, scientists still don’t know how to buffer its damaging effects without interfering with its normal roles in the body.
According to previous research, the LTBP3 protein associates with the TGFβ molecule to regulate its secretion, activation, and maturation. As a result, the scientists wondered what role LTBP3 itself might have in the development of metastasis.
The initial steps of tumor metastasis can occur when a primary tumor is barely detectable.
The researchers used chicken embryo tumor models and a rodent head and neck cancer model to discover how LTBP3 is involved in the spread of aggressive tumor cells.
In each model, the team found that without LTBP3, the primary tumor cells could not metastasize efficiently.
“Our experimental results showed that LTBP3 is active in the first steps of metastatic spread ,” according to the researchers.
Importantly, the new data is in line with the clinical findings that LTBP3 levels may indicate better overall survival in cancer patients with early-stage head and neck carcinomas.
Drugs to ‘prevent’ metastasis
The findings suggest that LTBP3 may be a good target in developing drugs to treat early-stage tumors without affecting more complex TGFβ functions in other parts of the body.
The next step will be to precisely investigate how LTBP3 and TGFβ biochemically associate in the induction of new blood vessels deep within a tumor.
