Apatinib enhances the antitumor effects of radiation in HeLa cell line mouse model of invasive cervical cancer.

Background: There is the lack of reports on apatinib (APA) combined with radiation in the treatment of cervical cancer. The aim of our study was to investigate the anti-tumor effect of APA combined with radiation using an in vivo model of cervical cancer. Methods: The mouse models, established using Henrietta Lacks (HeLa) cells, were randomly divided into 4 groups: the control group, radiotherapy (RT) alone group, cisplatin (DDPs) combination RT group (DDPs + RT), and APA combination RT group (APA + RT). The expressions of the vascular endothelial growth factor receptor-2 (VEGFR-2), platelet endothelial cell adhesion molecule-1 (CD31), proliferating cell nuclear antigen (Ki-67), and histone H2AX family member (γ-H2AX) were determined using immunohistochemistry (IHC), the extent of apoptosis was determined using terminal deoxynucleotidyl transferase (TdT)-mediated (dUTP) nick-end labeling (TUNEL), and tumor metabolism was determined using micro18F-fluorodexyglucose positron emission tomography/computed tomography. The length of survival was observed and recorded. Results: The positive expressions of VEGFR-2, CD31, and Ki-67 in the APA + RT group were obviously reduced compared with the control, RT, and DDPs + RT groups (P<0.05). The positive expression of γ-H2AX was obviously increased compared with the control and RT groups (P<0.05), whereas the apoptosis rate in the APA + RT group was obviously increased compared with the control, RT, and DDPs + RT groups (P<0.05). The tumor metabolism and volume in the APA + RT group were obviously reduced compared with the control, RT, and DDPs + RT groups. The length of survival was prolonged by 22 and 11 days in the APA + RT group compared with the RT and DDPs + RT groups, respectively (P<0.05). Conclusions: The combination of APA and RT could significantly enhance the anti-tumor efficacy of RT and prolong the median survival in a mouse model of cervical cancer.

[Effects of arsenic trioxide, ginseng saponin and beta-elemene on telomere-telomerase system in K562 cell line].

The aim was to explore the modulating and inhibiting effects of arsenic trioxide, ginseng saponin and beta-elemene on telomere length and telomerase activity in K562 cell line, and to study their anti-tumor mechanism and seek new method of therapy for acute leukemia. Human erythroleukemia cell line K562 was co-cultured with arsenic trioxide, ginseng saponin, beta-elemene separately, cells were collected after 24, 48 and 72 hours for further detecting. Telomere length and telomerase activity were detected by the methods of Southern-blot and PCR-ELISA respectively. The effects of these drugs on telomere length and telomerase activity were observed at different concentrations and length of time. The results showed that (1) telomerase activity of K562 cells decreased after co-cultured with arsenic trioxide, ginseng saponin and beta-elemene. The inhibiting effects depended on drug concentrations and length of time. When co-cultured at proper concentration and period of time, telomerase activity could be inhibited; (2) viability of K562 cells decreased after co-cultured with arsenic trioxide, ginseng saponin and beta-elemene, the inhibiting effect depends on drug concentrations and length of time; (3) after co-cultured with arsenic trioxide, ginseng saponin, and beta-elemene for 72 hours, telomere length of K562 cell line prolonged a little. It is concluded that (1) arsenic trioxide, ginseng saponin and beta-elemene can inhibit telomerase activity in K562 cell line, the suppression of telomerase activity may be one of the mechanisms of anti-tumor effect; (2) arsenic trioxide, ginseng saponin and beta-elemene can inhibit the growth of K562 cell line, the inhibiting effect depends on concentration and time; (3) when telomerase activity was suppressed, the telomere length prolonged a little, indicating that in K562 cell line may exist another mechanism to regulate telomere length, except telomerase activation.

[The relationship between telomerase activity and cell cyele in acute leukemia cells].

To explore the change of telomerase activity in acute leukemia (AL) cells and its relationship with cell cycle, PCR-ELISA was used to detect telomerase activity of bone marrow cells from 148 AL patients, including 92 cases with acute non-lymphocytic leukemia (ANLL) and 56 cases with acute lymphocytic leukemia (ALL). Thirty-six patients without bone marrow disorders were detected as normal control. The cell cycle of 16 patients and 4 controls was detected with flow cytometry. The results showed that the positive rate of telomerase was 71.6% (106/148) in the cells from AL patients, which was higher than that in the control group 5.6% (2/36). It was 88.9% (32/36) in the relapse group and 81.3% (61/75) in the untreated group. Both rates were higher than that in the CR group (35.1%, 13/37). There was no significant difference in the ALL and ANLL groups. The cell number in various phases of cell cycle had no significant difference between telomerase positive and negative groups. It was concluded that the activation of telomerase was very common in acute leukemia cells. Telomerase positive rate was closely associated with the different stages and progress of acute leukemia, and it might be a molecular marker for increased proliferation of leukemic cells during the process of the disease. Activation of telomeras had no correlation with cell number in different phases of cell cycle, while telomerase activity is modulated by other biological factors in addition to cell cycle.