There have been many attempts to deliver cancer drugs directly to the proper target, with varied success. One proposal has taken a major step forward; scientists have reported success in the use of sperm as way to get drugs to the right place at the right time. The work has been published in Medical Physics, and is summarized in the following video.
Drugs have to enter the system before they can exert an effect, and often, that can mean it takes a long time for them to get there, and even then there may be difficulty accessing the tissue. Cancers of the female reproductive system present just such a challenge, leading Mariana Medina-Sánchez and colleagues at the Institute for Integrative Nanosciences in Germany to utilize sperm as drug couriers to fight endometriosis, pelvic inflammatory diseases, and even gynecological cancer.
The researchers created a system in which sperm simply absorb large amounts of the active ingredient of a tumor drug. That turned out to be as simple as soaking the sperm in a drug solution. The sperm are then directed into a micromachine structure like an iron-coated harness that self-tightens around the head of the sperm. The iron coating allows the sperm to be controlled by an external magnetic field.
There is also a release mechanism on the harness, so when the sperm encounters a surface, they are freed up to swim anywhere. The sperm can thus be directed to their target, and released to burrow into a tumor with their drug in tow.
The scientists tested their invention by using bull sperm, which have a size that is comparable to human sperm, and a chemotherapy drug called Doxorubicin. In HeLa cells and spheroids, a common cancer model used in the lab, the researchers learned that the harness slowed the sperm down by 43 percent. However, the sperm still was effective in penetrating the spheroids and killing cancer cells.
Sperm has many advantages over other proposed delivery modes like bacteria, which can cause unintended immune responses or pose a risk from proliferation. Sperm are also able to cart the drug intact to the target without degrading it.
Understandably there is still a lot of work to be done. Fore example, the researchers have to know more about the ultimate fate of the released harnesses. But it’s an intriguing possibility that the researchers want to test with human sperm. This could be a new avenue in the fight against gynecological cancer, which affects 100,000 women in the United States alone every year.
Sources: MIT Technology Review, Medical Physics