New Experimental Drug Kills Cancer Cells When Combined With Chemotherapy

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Katherine Tanner
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Credit: National Cancer Institute

Although the traditional chemotherapy drug, cisplatin, is somewhat successful in its own right, researchers have discovered that when combined with a new experimental drug the results are astounding. In a recent University of Michigan study carried out using mice, researchers found that when this combination was used in mice it destroyed a rare form of salivary gland tumor and stopped it from recurring within a 300 day period.


This rare form of cancer in question is called *adenoid cystic carcinoma, or ACC for short. It affects around 3,000 to 4,000 people annually and is most commonly found in the salivary glands. Unfortunately, it’s one of those cancer’s that isn’t usually detected until it’s at an advanced stage, is very resistant to therapy, and as of yet has no cure. Normally these type of tumors is treated with surgery and radiation. Chemotherapy is usually avoided as ACC is very slow-growing and chemotherapy is better used on rapidly growing tumors, confirmed Jacques Nor, a UM professor of dentistry, otolaryngology, and biomedical engineering, and principal investigator on the study.

The experimental drug used in the study is called MI-773,  and when combined with cisplatin, is very effective at warding off cancer. It does this by preventing the interaction taking place that disarms the vital cancer-fighting protein, p53. As the researchers explain it, by blocking that interaction, ACC cancer cells become sensitized to cisplatin. “This drug MI-773 prevents that interaction, so p53 can induce cell death,” says Nor. “In this study, when researchers activated p53 in mice with salivary gland cancer, the cancer stem cells died.”


As part of the study, researchers carried out two different types of experiments in order to fully test how much the ACC tumors were reducing in size as well as their recurrence patterns. The first experiment involved treating tumors in mice with the combination of MI-773 and cisplatin.  The results were that the tumors shrank considerably from around the size of an acorn to almost nothing. In the second experiment, researchers removed the acorn sized tumors surgically and followed it up with one month’s worth of MI-773 treatment.

“We did not observe any recurrence in the mice that were treated with this drug after 300 days (about half of mouse life expectancy), and we observed about 62 percent recurrence in the control group that had only the surgery,” said Nor. “It’s our belief that by combining conventional chemotherapy with MI-773, a drug that kills more cancer stem cells, we can have a more effective surgery or ablation.” One slight drawback to the study is that it is based on an observational period of 300 days, whereas nearly half of all ACC tumors recur only after around 10 years. It’s still early days for the drug combo in terms of being used on human patients but is still a good place to start nonetheless.


*Adenoid cystic carcinoma (ACC) is an uncommon form of malignant neoplasm that arises within secretory glands, most commonly the major and minor salivary glands of the head and neck. Other sites of origin include the trachea, lacrimal gland, breast, skin, and vulva. This neoplasm is defined by its distinctive histologic appearance. Source: The Oral Cancer Foundation

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