Developing a non-toxic approach to bone-crushing cancers

When cancer spreads to the bone the results can be devastating

Battling cancer is always a balancing act. The methods we use – surgery, chemotherapy and radiation – can help remove the tumors but they often come at a price to the patient. In cases where the cancer has spread to the bone the treatments have a limited impact on the disease, but their toxicity can cause devastating problems for the patient. Now, in a CIRM-supported study, researchers at UC Irvine (UCI) have developed a method they say may be able to change that.

Bone metastasis – where cancer starts in one part of the body, say the breast, but spreads to the bones – is one of the most common complications of cancer. It can often result in severe pain, increased risk of fractures and compression of the spine. Tackling them is difficult because some cancer cells can alter the environment around bone, accelerating the destruction of healthy bone cells, and that in turn creates growth factors that stimulate the growth of the cancer. It is a vicious cycle where one problem fuels the other.

Now researchers at UCI have developed a method where they combine engineered mesenchymal stem cells (taken from the bone marrow) with targeting agents. These act like a drug delivery device, offloading different agents that simultaneously attack the cancer but protect the bone.

Weian Zhao; photo courtesy UC Irvine

In a news release Weian Zhao, lead author of the study, said:

“What’s powerful about this strategy is that we deliver a combination of both anti-tumor and anti-bone resorption agents so we can effectively block the vicious circle between cancers and their bone niche. This is a safe and almost nontoxic treatment compared to chemotherapy, which often leaves patients with lifelong issues.”

The research, published in the journal EBioMedicine, has already been shown to be effective in mice. Next, they hope to be able to do the safety tests to enable them to apply to the Food and Drug Administration for permission to test it in people.

The team say if this approach proves effective it might also be used to help treat other bone-related diseases such as osteoporosis and multiple myeloma.

Stem Cell Scientists Reconstruct Disease in a Dish; Gain Insight into Deadly Form of Bone Cancer

The life of someone with Li-Fraumeni Syndrome (LFS) is not a pleasant one. A rare genetic disorder that usually runs in families, this syndrome is characterized by heightened risk of developing cancer—multiple types of cancer—at a very young age.

People with LFS, as the syndrome is often called, are especially susceptible to osteosarcoma, a form of bone cancer that most often affects children. Despite numerous research advances, survival rates for this type of cancer have not improved in over 40 years.

shutterstock_142552177 But according to new research from Mount Sinai Hospital and School of Medicine, the prognosis for these patients may not be so dire in a few years.

Reporting today in the journal Cell, researchers describe how they used a revolutionary type of stem cell technology to recreate LFS in a dish and, in so doing, have uncovered the series of molecular triggers that cause people with LFS to have such high incidence of osteosarcoma.

The scientists, led by senior author Ihor Lemischka, utilized induced pluripotent stem cells, or iPSCs, to model LFS—and osteosarcoma—at the cellular level.

Discovered in 2006 by Japanese scientist Shinya Yamanaka, iPSC technology allows scientists to reprogram adult skin cells into embryonic-like stem cells, which can then be turned into virtually any cell in the body. In the case of a genetic disorder, such as LFS, scientists can transform skin cells from someone with the disorder into bone cells and grow them in the lab. These cells will then have the same genetic makeup as that of the original patient, thus creating a ‘disease in a dish.’ We have written often about these models being used for various diseases, particularly neurological ones, but not cancer.

“Our study is among the first to use induced pluripotent stem cells as the foundation of a model for cancer,” said lead author and Mount Sinai postdoctoral fellow Dung-Fang Lee in today’s press release.

The team’s research centered on the protein p53. P53 normally acts as a tumor suppressor, keeping cell divisions in check so as not to divide out of control and morph into early-stage tumors. Previous research had revealed that 70% of people with LFS have a specific mutation in the gene that encodes p53. Using this knowledge and with the help of the iPSC technology, the team shed much-needed light on a molecular link between LFS and bone cancer. According to Lee:

“This model, when combined with a rare genetic disease, revealed for the first time how a protein known to prevent tumor growth in most cases, p53, may instead drive bone cancer when genetic changes cause too much of it to be made in the wrong place.”

Specifically, the team discovered that the ultimate culprit of LFS bone cancer is an overactive p53 gene. Too much p53, it turns out, reduces the amount of another gene, called H19. This then leads to a decrease in the protein decorin. Decorin normally acts to help stem cells mature into healthy, bone-making cells, known as osteoblasts. Without it, the stem cells can’t mature. They instead divide over and over again, out of control, and ultimately cause the growth of dangerous tumors.

But those out of control cells can become a target for therapy, say researchers. In fact, the team found that artificially boosting H19 levels could have a positive effect.

“Our experiments showed that restoring H19 expression hindered by too much p53 restored “protective differentiation” of osteoblasts to counter events of tumor growth early on in bone cancer,” said Lemischka.

And, because mutations in p53 have been linked to other forms of bone cancer, the team is optimistic that these preliminary results will be able to guide treatment for bone cancer patients—whether they have LFS or not. Added Lemischka:

“The work has implications for the future treatment or prevention of LFS-associated osteosarcoma, and possibly for all forms of bone cancer driven by p53 mutations, with H19 and p53 established now as potential targets for future drugs.”

Learn more about how scientists are using stem cell technology to model disease in a dish in our special video series: Stem Cells In Your Face: