Telomerase is activated in human papillomavirus (HPV) positive cervical cancer 
and targeting telomeres offers a novel anticancer therapeutic strategy. In this 
study, the telomere targeting properties, the cytotoxic as well as the 
pro-apoptotic effects of hexane (IV-HE) and dichloromethane (IV-DF) fractions 
from Inula viscosa L. extracts were investigated on human cervical HeLa and SiHa 
cancer cells. Our data demonstrate that IV-HE and IV-DF extracts were able to 
inhibit cell growth in HeLa and SiHa cells in a dose-dependent manner and 
studied resistant cell lines exhibited a resistance factor less than 2 when 
treated with the extracts. IV-HE and IV-DF extracts were able to inhibit 
telomerase activity and to induce telomere shortening as shown by telomeric 
repeat amplification protocol and TTAGGG telomere length assay, respectively. 
The sensitivity of fibroblasts to the extracts was increased when telomerase was 
expressed. Finally, IV-HE and IV-DF were able to induce apoptosis as evidenced 
by an increase in annexin-V labeling and caspase-3 activity. This study provides 
the first evidence that the IV-HE and IV-DF extracts from Inula viscosa L. 
target telomeres induce apoptosis and overcome drug resistance in tumor cells. 
Future studies will focus on the identification of the molecules involved in the 
anticancer activity.