CHICAGO, Aug. 16 (Xinhua) -- An experimental drug combined with the traditional chemotherapy drug cisplatin destroyed a rare form of salivary gland tumor in mice and prevented a recurrence within 300 days, a University of Michigan (UM) study found.
Typically, oncologists treat this rare cancer called adenoid cystic carcinoma, or ACC, with surgery and radiation, and rarely use chemotherapy as ACC is extremely slow-growing, and chemotherapy works best on cancers where cells divide rapidly and tumors grow quickly, said Jacques Nör, a UM professor of dentistry, otolaryngology and biomedical engineering and principal investigator on the study.
The Nör lab treated ACC tumors with a novel drug called MI-773, and then combined MI-773 with traditional chemotherapy cisplatin. MI-773 prevents a molecular interaction that causes tumor cells to thrive by disarming the critical cancer fighting protein, p53.
Study co-author Shaomeng Wang, UM professor of medicine, pharmacology and medicinal chemistry, discovered MI-773.
Researchers believe that blocking that interaction sensitized ACC cancer cells to cisplatin, a drug that under normal conditions wouldn't work. When administered to the mice with ACC tumors, the cisplatin targeted and killed the bulk cells that form the tumor mass, while MI-773 killed the more resistant cancer stem cells that cause tumor recurrence and metastasis.
"This drug MI-773 prevents that interaction, so p53 can induce cell death," Nör said.
"We did not observe any recurrence in the mice that were treated with this drug after 300 days, and we observed about 62 percent recurrence in the control group that had only the surgery," Nör said. "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 limitation of the study is that about half of all ACC tumors recur only after about 10 years, and this observational period was only 300 days.
It is still too early to know how humans will respond. Besides, the drug will work primarily in tumors where p53 is normal. If p53 is mutated, which is fairly common in other tumor types, this drug won't work as well, Nör said.
ACC is a rare cancer that affects 3,000-4,000 people annually, and typically arises in the salivary glands. It's usually diagnosed at an advanced stage, is very resistant to therapy, and there's no cure.
