Objective: To study effects of hypericin associated with radiotherapy on human laryngeal squamous cell carcinoma strain Hep-2.
Method: Using techniques of tumor cells culture in vitro, Hep-2 cells were exposed to different concentration hypericin as 0, 1.0, 2.0, 3.0 microg/ml, then 5 Gy radiation were given after an hour. Other groups Hep-2 culture cells were also exposed to different concentration hypericin as 5, 10, 20, 25 microg/ml, and no radiation were given. In all groups, contrast group was set up. And 48 hours later, growth characteristics of Hep-2 were studied by morphological observation, MTT assay and flow cytometry.
Result: In normal contrast group, Hep-2 cells grew intensively and contacted with each other. And cellular swelling was found when Hep-2 cells were only treated with radiotherapy. When Hep-2 cells were treated with both Hypericin and radiotherapy, more cells swelled and cell number declined greatly. In higher dose Hypericin group, necrosis could be found. MTT assay showed the Hep-2 cells growth was significantly inhibited when treated with both hypericin and radiotherapy. Flow cytometry showed hypericin could block cell growth at G0/G1 phase and induced laryngeal cells into apoptosis whether with radiotherapy or not. But Hep-2 cells only treated with hypericin could not get same powerful effect as combination with radiotherapy.
Conclusion: Human laryngeal squamous cell carcinoma strain Hep-2 can be inhibited and induced into apoptosis by treated with hypericin combination with radiotherapy.