Positive association of long telomeres with the invasive capacity of hepatocellular carcinoma cells

Invasion, the representative feature of malignant tumors, leads to an increase in mortality. The malignant liver tumor - hepatocellular carcinoma (HCC) - has an enhanced invasive capacity that results in increased patient mortality. Moreover, this enhanced invasive capacity is due to the up-regulation of invasion promoters such as zinc finger protein SNAI1 (Snail) and matrix metalloproteinases (MMPs), and the down-regulation of invasion suppressor molecules such as E-cadherin. Telomerase reverse transcriptase (TERT), which encodes the catalytic subunit of telomerase, is highly expressed in a variety of invasive cancers, including HCC. Telomerase activation induces telomere elongation, thereby leading to cell immortalization during malignant tumor progression. However, the relationship between telomere length and invasion is yet to be experimentally corroborated. In this paper, we revealed that invasive HCC cells passing through the Matrigel display significantly longer telomeres than non-invasive HCC cells. Moreover, we established a method that can distinguish and sort cells containing long telomeres and short telomeres. Using this system, we observed that the HCC cells containing long telomeres had a high-level expression of invasion-promoting genes and a low-level expression of invasion-suppressing E-cadherin. Furthermore, HCC cells containing long telomeres exhibited a higher invasive capacity than HCC cells containing short telomeres. Taken together, our findings suggest that long telomeres are positively associated with the invasive capacity of HCC cells and may be a potent target for malignant liver cancer treatment.