Modern science has made a tremendous amount of progress involving cancer research and treatment in the last decades. New therapies and the latest cancer treatments now include new chemotherapy agents including monoclonal antibodies. (Read up on the wonder drug known as monoclonal antibodies in this Bold story.) But despite this, the battle to fight cancer is far from over. This is especially true when it comes to solid tumors, which can be among the most aggressive. This includes cancers such as pancreatic, renal, breast and brain tumors. However, researchers may have discovered an inherent vulnerability among these cancers. And exploiting this vulnerability could lead to a completely new approach to cancer care.
As it turns out, solid tumors have some unique features that cause them to have some specific weaknesses. This is particularly true for those that grow fast and outgrow their own blood and oxygen supply. When this happens, the tumors rely on a few specific proteins and enzymes to help it survive. And by disrupting the function of these proteins and enzymes, researchers believe these tumors could be conquered. This offers great hope for solid tumor treatment care if this latest cancer treatment research is successful.
“Cancer cells depend on the CAIX enzyme to survive, which ultimately makes it their ‘Achilles heel.’ By inhibiting its activity, we can effectively stop the cells from growing.” – Shoukat Dedhar, Cancer Research Specialist
Overview of Solid Tumor Growth
There are many different types of solid tumors that may occur. In some cases, these may be surgically removed with good success. But in other instances, surgery is not an option, or the tumors are aggressive and require additional care. Current solid tumor treatment in this regard can then be limited. The medications may have trouble penetrated the extent of the tumor or simply may be poorly effective. Even the latest cancer treatment options are limited in their success in more aggressive types. This is why researchers are actively seeking better solid tumor treatment opportunities.
In this regard, solid tumors do have some interesting qualities that have led to new discoveries. When solid tumors grow quickly, it is not uncommon for them to outgrow their blood supply. One might think this would lead to their demise, but that is not the case. In fact, when this does occur, the lack of oxygen to the tumor triggers the release of specific proteins. These proteins then provide alternative fuel for the solid tumor, letting it survive and spread. They also counteract the release of lactic acid and iron byproducts that would otherwise kill the cancer cells. Now that researchers understand these proteins better, they are focusing on blocking their function as the latest cancer treatment.
“At zero oxygen, the cell can’t survive. Inside a tumor you will see these regions of necrosis,” or dead cells. But those cells that are low on oxygen but still alive will produce new proteins: Key among them are HIF-1 and HIF-2.” – Daniele Gilkes, Johns Hopkins University School of Medicine.
New Solid Tumor Treatment Options
Understanding the unique growth features of some solid tumors, scientists are exploring new types of compounds. These solid tumor treatments involve various substances that affect hypoxic induction factors (HIF). Once scientists identify a specific factor, they are testing different types of solid tumor treatments. Some involve molecules that inhibit these factors while others combine a drug with an antibody. Likewise, initial studies are being performed in mice as Phase I trials. Thus far, some of these experiments are quite promising in the development of the latest cancer treatment for these tumors.
In terms of a specific solid tumor treatment, Peloton Therapeutics, Inc., has been testing one potential drug. Labelled PT2399, the drug essentially breaks one of the hypoxic induction factors in two. The specific factor has been termed HIF-2, and initial experiments have been performed in mice with renal cancer. In their experiments, the solid tumor treatment slowed growth of the cancer in 56% of mice. These results have attracted attention to this Dallas-based company. Many are hopeful this could be at least part of the latest cancer treatment combination for these types of tumors.
Peloton Therapeutics is not alone in the search for the latest cancer treatment breakthrough. Researchers out of the University of British Columbia are studying a different compound called CAIX. The substance, Carbonic Anhydrase IX, is another important protein in the hypoxic induction pathway when tumors outgrow their blood supply. Not only does CAIX help control the lactic acidosis associated with hypoxia. It also prevents cancer cells from absorbing too much iron that can lead to their demise. Researchers, however, have found that an inhibitor of CAIX, called SLC-0111, is quite powerful in its effects. Mice with brain, pancreatic, and breast cancer have all had a positive response to this solid tumor treatment.
“By understanding ferroptosis and how cells defend against it, we can develop therapeutic strategies to block those defense mechanisms and trigger cell death.” – Dr Boyi Gan, University of Texas MD Anderson Cancer Center
A New Strategy in Solid Cancer Treatment
These new discoveries of solid tumor treatment involving hypoxia pathways is certainly exciting. Drugs that could prevent these cancers from adapting to low circulation and low oxygen environments could be quite significant. If they’re unable to acquire fuel and energy, these cancer cells will cease to grow and die. This is why CAIX inhibitors and other similar drugs are being touted as the latest cancer treatment opportunity. As more pharmaceutical companies and researchers explore these options, new insights will be gained, further advancing personalized cancer care. And if results are favorable, this could be a preferred option for solid tumor treatment in the years to come.
