A new study by the University of Chicago Medical Center sheds light to the factors that help in preventing the spread of ovarian cancer.
The researchers found that a drug, which blocks production of an enzyme that enables ovarian cancer to gain a foothold in a new site can slow the spread of the disease and prolong survival, only if it is given early in the disease process.
In the study, the researchers show that an enzyme called MMP-2 is important for ovarian cancer to attach itself to the sites where it tends to spread.
And several drugs called MMP inhibitors, such as marimastat or prinomastat, inhibit the enzyme, dramatically reducing the tumour's ability to establish itself at sites beyond the ovary.
However such MMP inhibitors have to be provided before the cancer has spread.
"Our study suggests that MMP-2 inhibitors could have a significant impact on ovarian cancer but only if administered quite early, before the cancer has advanced beyond the ovary," said Ernst Lengyel, assistant professor of obstetrics and gynecology at the University of Chicago.
The researchers first wanted to figure out the steps required for ovarian cancer to dislodge from its original site and establish itself elsewhere in the peritoneal cavity.
Lengyel and colleagues found that one of the key steps was MMP-2 production by cancer cells that came in contact with the cells that line the peritoneal cavity.
When ovarian cancer cells come in contact with the cells that line this internal cavity, they produce MMP-2, an acronym for matrix metalloproteinase-2.
MMP-2 alters two proteins--vitronectin and fibronectin--present on the surface of the cells that line the cavity. These alterations change those proteins in a way that enables the cancer cells to latch on to them better. Once attached, the cancer cells can multiply rapidly and invade.
The researchers found that by inhibiting MMP-2 activity early in the disease course, they were able to prevent injected ovarian cancer cells from attaching to their target tissues in the peritoneum and omentum.
The inhibition of MMP-2 activity reduced the growth of new tumours by 68 percent, when measured four weeks after treatment.
Besides this, the inhibitor nearly doubled survival time in mice that were injected with ovarian cancer cells. Those who received it survived an average of 63 days, as compared to untreated mice, who survived only 36 days.
The researchers concluded that brief and early intraperitoneal treatment with an MMP inhibitor might reduce peritoneal attachment, metastases and significantly prolong survival.
The study is published in the Journal of Clinical Investigation.