A new “cancer trap,” featuring a protein “bait” and a chemotherapeutic drug lying in wait, promises to catch and kill rogue cancer cells.
One of the many problems with treating cancer is that rogue cells can break away from the primary tumor and travel to distant locations, causing the disease to spread or metastasize.
A new “cancer trap,” featuring a protein “bait” and a chemotherapeutic drug lying in wait, promises to catch and kill these rogue cells. Developed by Liping Tang, professor of bioengineering at the University of Texas at Arlington, the trap is not meant to fight the battle alone. Instead, it’s designed to complement conventional chemo and radiation therapies. While Tang admits the method’s effectiveness is difficult to measure, he believes the technique has a capacity to prolong patients’ lifespans by more than 25 percent.
The “trap” is created by 3-D printing a biodegradable, porous polymer scaffold. Polylactic acid, a common tissue engineering material, is one able candidate for the structure, Tang says.
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The trap holds two ingredients: a chemokine, or regulatory protein, that serves as bait and a chemotherapeutic agent that kills the cancer cell once it’s drawn into the trap. Chemokines are proteins that trigger a variety of biological cell responses, including tumor cell movement. That makes them an effective bait.
“Once a cancer cell is lured in, it will be eradicated,” Tang says. “So basically we will reduce metastatic cancer cells just like a roach motel attracts cockroaches and then eradicates them.”
To make the FDA approval process easier, all the components, including the chemokine and chemotherapy agent, are FDA-approved choices.
The trap is delivered into the body via an implantable capsule under the skin or through an injectable microparticle.
Researchers implant the capsule through a small incision. The benefit of the implant is that researchers can recover it at a later stage and study the contents. The rogue cancer cells that are caught can signal progression of the disease. The implant is made with biomaterials that are designed to minimize the body’s systemic immune responses to foreign objects.
The injectable microparticle that releases the chemokine and attracts cancer cells can be used for localized chemotherapy.
“Injectables are particularly suitable for cancers in tricky spots, in areas that are far away from the skin,” Tang says. “We want to inject it as close to the tumor as possible.”
Tang’s approach raises questions. If these cancer traps can attract distant cancer cells so effectively, why does their positioning matter so much? And if a cancer has already metastasized, how does a doctor or clinician decide where to place the traps to prevent it from getting worse?
“It is well established that metastatic cancer cells migrate out of the primary tumor and go through the lymph node and through the blood to secondary sites,” Tang says.
The ideal locations to increase chances of success are close to tumor sites and near lymph nodes and related vasculature.
“These metastatic cells—we call them cancer stem cells–move a lot and proliferate very fast,” he says. “That’s what the cancer trap is designed for. Once you place the trap near them, the cancer stem cells migrate toward the trap and are killed. This way, even when they get out of the bloodstream and out of the lymph node, they don’t spread elsewhere.”
If these chemokines-chemotherapy combos are so effective, why not dispatch them all over the body to kill rogue cells instead of devising elaborate traps to catch them?
“Imagine if you released a pheromone for the roach motel all over the house,” Tang says. “You still don’t know where the roaches are. They might be hiding behind the couch and you don’t know if you have killed them. It’s the same with the cancer cells. If we put a trap near the place where there’s a high chance of a cancer cell going through, like a lymph node, it’s more effective for subsequent eradication.”
The cancer trap can also be used in early diagnosis of metastasis.
“If you suspect there’s a cockroach, you can either put down bait or sit in the kitchen for hours on end to see whether it shows up,” he says “The trap acts like a cancer concentrator, and by analyzing the cells inside the [implanted] device, you can tell whether the cancer is spreading.”
The cancer trap has received a patent in Europe. Tang is awaiting funding to take the developments to clinical trials in the United States.
Poornima Apte is an independent technology writer.
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