2-Hexyl-4-Pentylenic Acid(HPTA) Stimulates the Radiotherapy-induced Abscopal Effect on Distal Tumor through Polarization of Tumor-associated Macrophages

Objective The aim of this study was to explore the effects of 2-hexyl-4-pentylenic acid(HPTA)in combination with radiotherapy(RT)on distant unirradiated breast tumors.Methods Using a rat model of chemical carcinogen(7,12-dimethylbenz[a]anthracene,DMBA)-induced breast cancer,tumor volume was monitored and treatment response was evaluated by performing HE staining,immunohistochemistry,immunofluorescence,q RT-PCR,and western blot analyses.Results The results demonstrated that HPTA in combination with RT significantly delayed the growth of distant,unirradiated breast tumors.The mechanism of action included tumor-associated macrophage(TAM)infiltration into distant tumor tissues,M1 polarization,and inhibition of tumor angiogenesis by IFN-γ.Conclusion The results suggest that the combination of HPTA with RT has an abscopal effect on distant tumors via M1-polarized TAMs,and HPTA may be considered as a new therapeutic for amplifying the efficacy of local RT for non-targeted breast tumors.

Hexyl-pentynoic acid serves as a novel radiosensitizer for breast cancer by inhibiting UCHL3-dependent Rad51 deubiquitination

Objective:To investigate the effects and underlying mechanism of 2-hexyl-4-pentynoic acid(HPTA),a derivative of valproic acid(VPA),on radiotherapy in breast cancer.Methods:MCF7 cells and 7,12-dimethylbenz-[α]-anthracene(DMBA)-induced transformed human normal breast cells(MCF10A–DMBA cells)were irradiated with 8 Gy X-rays.For both cells there were four groups:control,valproic acid(VPA)/HPTA,IR,and VPA/HPTA+IR groups.MTT and clonogenic survival assays were performed to assess cell proliferation,and comet assay was performed to evaluate DNA damage.Protein expression ofγH2AX,53BP1,Rad51,and BRCA1 was examined via immunofluorescence and immunoblotting.Cycloheximide chase and ubiquitination experiments were conducted to determine Rad51 ubiquitination.In vivo experiments involved a rat model of DMBA-induced breast cancer,with four fractionated doses of 2 Gy.Tumor tissue pathological changes andγH2AX,Rad51,and UCHL3 expression levels were measured by hematoxylin-eosin staining,immunohistochemistry,and immunoblotting.Results:Compared with the IR group,15μmol/L HPTA reduced the cell proliferation ability of irradiated MCF7 cells(t=2.16,P<0.05).The VPA/HPTA+IR group exhibited significantly increased DNA double-strand breaks relative to those in the IR group(VPA+IR vs.IR,t=13.37,P<0.05;HPTA+IR vs.IR,t=8.48,P<0.05).Immunofluorescence and immunoblotting experiments demonstrated that the VPA/HPTA+IR group displayed signifi-cantly increased cell foci formation,γH2AX and 53BP1 protein expression levels compared to the IR group[(γH2AX:VPA+IR vs.IR,t=8.88,P<0.05;HPTA+IR vs.IR,t=8.90,P<0.05),(53BP1,VPA+IR vs.IR,t=5.73,P<0.05;HPTA+IR vs.IR,t=6.40,P<0.05)].Further,Rad51 expression was downregulated(VPA+IR vs.IR,t=3.12,P<0.05;HPTA+IR vs.IR,t=2.70,P<0.05),and Rad51 inhibition effectively counteracted HPTA-induced radiosensitization.Ubiquitination detection further verified that HPTA inhibits Rad51 expression via UCHL3-dependent Rad51 deubiquitination.In vivo study results showed that 20 mg/kg HPTA significantly enhanced the radiosensitivity of breast tumors in rats by inhibiting Rad51 expression.Conclusions:HPTA is a highly effective radiosensitizer that enhances the radiotherapeutic efficacy of breast cancer treatment through UCHL3-dependent deubiquitination of Rad51.

表观遗传试剂诱导海洋真菌Aspergillus versicolor DJ013产生次级代谢产物的研究

目的对1株来源于浙江东极岛海域沉积物的海洋真菌Aspergillusversicolor进行表观遗传试剂2-hexyl-4-pentynoic acid诱导并研究其次级代谢产物。方法采用溶剂萃取、柱层析色谱及制备色谱等方法对化合物进行分离纯化,通过LC-MS和NMR等方法进行结构鉴定,采用滤纸片扩散法测定抗菌活性。结果在表观遗传试剂2-hexyl-4-pentynoic acid诱导下,从Aspergillus versicolor分离得到3个化合物,经结构鉴定为弯孢霉菌毒素(1)、cyclo-(L-Trp-L-Phe)(2)和diorcinol(3)。