| Hypocrellin,a type of perylenequinones pigment,is the major components in extract from Tabasheer stroma.There are two main types of natural bamboo red rhzomorph components,including hypocrellinA(HA)and hypocrellin B(HB).Among all of these,more than 95%is HA,in alkaline conditions,HA can be dehydrated into HB.Studies have shown that HB can be used as a new type of photodynamic antitumor drugs.Compared with hematoporphyrin derivative(HpD),HB has many advantages,such as single and certain chemical composition,easy purification and low toxicity and so on.At present,photodynamic therapy(PDT)has been used in the treatment of skin cancer such as superficial tumors,but the restricted light penetration in the biological tissue limits its curative effect in deep tumor tissue.However,in comparison with PDT,SDT shows many advantages,such as deep penetrating,high aggregation and the regional optionality,etc.All above these have certain curative effect for some deep tumor treatment.Recent research have suggested that HB may be a kind of effective sonosensitizer which can inhibit proliferation of a variety of tumor cells.Alignant tumor is a kind of serious illness which is harm to people’s health and life.In many countries and regions,malignant tumor has become the first cause for resident disease.Among all of the malignant tumors,gastric cancer occupies a considerable proportion.In our country,the morbidity and mortality of gastric cancer rank first among all malignant tumors,what’s even worse is that it has a rising trend year by year.At present,chemotherapy has become an important role in clinical treatment for the middle-late gastric cancer and postoperative recurrence of metastatic gastric cancer.But with the widely application of the chemotherapy drugs,multidrug resistance(MDR)has become the primary cause which hinders the success chemotherapy of the gastric cancer.Therefore,the study about how to overcome the tumor MDR will propel the effective chemotherapy breakthrough and create a broad prospect for the tumor treatment.Existing researches have shown that the sonodynamic therapy mediated by HB(HB-SDT)can significantly inhibit the proliferation of tumor cells and induce cell apoptosis.But the research about killing effect and mechanism to drug-resistant cell line after the joint treatment of HB-SDT and DOX have not been reported.In this research,we selected human gastric cancer cell line SGC7901 cells and corresponding adriamycin resistant cell strain SGC7901/ADR cells as the research model,and then probed their damage effect after the treatment of HB-SDT.In addition,we also preliminarily discussed killing effect on SGC7901/ADR cells and its molecular mechanism after the joint processing of HB-SDT and DOX.The experimental results were as follows.1.HB-SDT inhibit cell proliferation and induct apoptosis of human gastric cancer SGC7901 cells and SGC7901/ADR cellsThis study first detected the inhibitory effect on human gastric cancer SGC7901 cells and SGC7901/ADR cells after the HB-SDT treatment by MTT assay.The result showed that HB alone had no dark toxicity on above two cell lines,but HB-SDT can significantly reduce their cell survival rate.In addition,the experimental data manifested that under the experiment processing with the same drug concentration and ultrasonic intensity,SGC7901/ADR cells displayed greater decline of cell survival rate.In addition,Guava Viacount experiment also verified above results.Next,through fluorescent microscopy we observed that cells exhibited obvious morphological changes under HB-SDT treatment,such as getting round cells,the formation of cell debris,chromatin pyknosis and DNA fragmentation and so on.Furthermore,we observed that SGC7901/ADR cells exhibited more significant morphological damage under the same processing conditions.In addition,the experiment combining flow cytometry and fluorescent dyesfluorescent dye AnnexinV-PE/7-AAD showed that SGC7901/ADR cells displayed more prominent apoptosis after the treatment of HB-SDT.Besides,we use flow cytometry detected greater loss of MMP and more remarkable increase ROS level in SGC7901/ADR cells.2.Disparate cell membrane fluidity leading to different cell membrane damage degree may be one of the reasons which caused different lethal effect on SGC7901 cells and SGC7901/ADR cells after HB-SDT.Drug intake experiments showed that cellular uptake of HB in above two kinds of cells had no difference;Flow cytometry instrument combining FD500 staining assay indicated that HB-SDT could more significantly increase cell membrane permeabilityof SGC7901/ADR cells;We observed that SGC7901/ADR cells had more obvious cell membrane ultrastructural changes under the same processing conditions through SEM.Fluorescence polarization experiment result showed that compared with SGC7901/ADR cells,SGC7901 cells showed better cell membrane fluidity.3.HB-SDT synergistically enhances the anti-tumor effect of DOX on SGC7901/ADR cells.MTT experiments confirmed that SGC7901/ADR cells had good resistance to DOX.The combination treatment of HB-SDT and DOX had significant cytotoxicity on SGC7901/ADR cells.GuavaViacount detection experiments also further validated above synergy effect.Apoptosis was analyzed using AnnexinV-PE/7-AAD staining.A conspicuous augment on apoptosis rate was detected after the combined treatment with HB-SDT and DOX.We also detected that the level of ROS generation in SGC7901/ADR cells had substantial growth when combined DOX and HB-SDT.Fluorescence microscopy revealed that HB-SDT could obviously suppress Rhodamine-efflux.Meanwhile,immunofluorescence results demonstrated that the combining treatment of DOX and HB-SDT can significantly decrease" the expression level of P-gp.In addition,western blotting analysis revealed that DOX and HB-SDT synergistically decreased the ratio of Bcl-2/Bax and the expression of P-gp. |
PDF Full Text Request