PI3K Inhibitor Promotes The Tumor Vessel Normalization And Improves The Treatment Of Breast Cancer With Doxorubicin

Tumor vessels are abnormal,which is different from the structure and function of the normal tissue.Because of the abnormal structure and function of tumor blood vessels,anti-tumor drugs are difficult to transport to the deep part of tumor tissue,and the abnormal metabolism of tumor microenvironment caused by abnormal tumor blood vessels also hinders the development of cytotoxicity of anti-tumor drugs.The concept of "tumor vascularization" is the use of anti-angiogenic drugs to promote the transformation of tumor blood vessels into normal vessels and further increase the therapeutic effect of antitumor drugs.HS-173 is a specific inhibitor of PI3K ? subtype.Recent studies have shown that HS-173 can inhibit tumor angiogenesis.In this study,we further investigated the effects of HS-173 on tumor vascular structure,function and chemotherapeutic drug delivery in tumor tissues.In this experiment,mouse breast cancer subcutaneous transplantation was constructed,then,the morphological characteristics of the tumor tissue and the abnormal blood vessels were detected by HE staining,providing an experimental model for the follow-up experiments.Then,the mice were treated with different concentration of HS-173.The effects of HS-173 on the tumor growth were detected by vernier caliper and ultrasound.The MVD in tumor was tested by immunohistochemical staining,which we can learn the effect of HS-173 on tumor angiogenesis.Then,the mice were treatd by HS-173 or DOX alone,or by HS-173 and DOX in combination.After treatments,the morphology and the integrity of the tumor blood vessel were detected by immunofluorescence;the connections between endothelial cells and the integrity of the basement membrane were detected by transmission electron microscopy;then,the blood perfusion of the tumor was detected by Doppler ultrasound;The penetration of DOX in the tumor tissues was detected by living body imaging of small animals,and the treatment effect was determined by the volume size of the tumor after the treatment.The downstream signal molecules and angiogennic factors of PI3K were detected by immunohistorchemica staining.1.PI3K inhibitor affects the growth and angiogeesis of tumorFemale BABL/C mice were used to establish 4T1 subcutaneous transplanted tumor model of breast cancer at the age of 6 to 8 weeks to observe the growth of subcutaneous transplanted tumor and the animal model was obtained..The area and length of tumor were monitored by small animal ultrasound after treatment,The tumor tissue of mice was made into paraffin sections on the 20 th day after inoculation,and breast cancer tissue and the vascular feature were identified by HE staining.Immunohistochemical staining was used to detect the expression of vascular endothelial marker(CD31)in tumor tissues after treatment.The results showed that different concentration of HS-173 reduced the number of tumor mesenchymal microvessels.Compared with the control group,there was statistical significance(P<0.05).2.PI3K inhibitor promoted the tumor vessel normalization and the drug delivery of doxorubicinThe tumor volume were monitored by ultrasound after treatment.The results showed that the volume of tumor decreased after treatment with DOX and HS-173,especially in HS-173 group.The tumor volume of mice treated with DOX and HS-173 was the smallest,which was significantly different from that of control group(P< 0.05).The vascular endothelial integrity was detected by immunofluorescence labeling CD31.The results showed that after HS-173 treatment,the integrity of vascular lumen increased and the loss of vascular lumen decreased.The vascular morphology of tumor stroma was observed under light microscope.The results showed that the interstitial vascular lumen was continuous,intact and abnormal branches decreased after HS-173 treatment.Doppler ultrasound was used to monitor the blood flow signal in the tumor tissue of mice.The results showed that HS-173 could increase the blood flow perfusion in the tumor tissue,which was the blood flow perfusion in the deep part of the tumor tissue,which was beneficial to the delivery of chemotherapy drugs.In order to reveal the delivery of DOX in tumor tissues,the fluorescence intensity of DOX in tumor tissue was detected by in vivo imaging of small animals.The results showed that HS-173 could increase the delivery of DOX in tumor tissues compared with DOX alone.The expression of vascular endothelial growth factor VEGF was detected by immunohistochemical staining.The results showed that compared with the control group,the expression of VEGF in the tumor tissues of each group were decreased after different administrations,especially in the combined treatment group.The expression of PI3K downstream signal molecule p-Akt was detected by immunohistochemical staining.The results showed that the expression of p-Akt in HS-173 group and combined treatment group were significantly lower than that in control group and DOX group(P < 0.01).The expression of Ki67,a cell proliferation marker,was detected by immunohistochemical staining.The results showed that there was no significant difference in the expression of Ki67 in tumor tissues of different treatment groups.