Promotion effect of FOXCUT as a microRNA sponge for miR-24-3p on progression in triple-negative breast cancer through the p38 MAPK signaling pathway

Background:Triple-negative breast cancer(TNBC)is a type of highly invasive breast cancer with a poor prognosis.According to new research,long noncoding RNAs(lncRNAs)play a significant role in the progression of cancer.Although the role of lncRNAs in breast cancer has been well reported,few studies have focused on TNBC.This study aimed to explore the biological function and clinical significance of forkhead box C1 promoter upstream transcript(FOXCUT)in triple-negative breast cancer.Methods:Based on a bioinformatic analysis of the cancer genome atlas(TCGA)database,we detected that the lncRNA FOXCUT was overexpressed in TNBC tissues,which was further validated in an external cohort of tissues from the General Surgery Department of the First Affiliated Hospital of Nanjing Medical University.The functions of FOXCUT in proliferation,migration,and invasion were detected in vitro or in vivo.Luciferase assays and RNA immunoprecipitation(RIP)were performed to reveal that FOXCUT acted as a competitive endogenous RNA(ceRNA)for the microRNA miR-24-3p and consequently inhibited the degradation of p38.Results:lncRNA FOXCUT was markedly highly expressed in breast cancer,which was associated with poor prognosis in some cases.Knockdown of FOXCUT significantly inhibited cancer growth and metastasis in vitro or in vivo.Mechanistically,FOXCUT competitively bounded to miR-24-3p to prevent the degradation of p38,which might act as an oncogene in breast cancer.Conclusion:Collectively,this research revealed a novel FOXCUT/miR-24-3p/p38 axis that affected breast cancer progression and suggested that the lncRNA FOXCUT could be a diagnostic marker and therapeutic target for breast cancer.

Pingxiao capsule(平消胶囊)inhibits lung metastasis of triple-negative breast cancer and sensitizes breast cancer to radiotherapy

OBJECTIVES: To investigate the anticancer effect of Pingxiao capsule(平消胶囊, PXC) on the treatment of breast cancer in vitro and in vivo. METHODS: The inhibition of PXC on cell viability and proliferation was determined by cell counting kit-8, EdU assay and colony formation assay, respectively. The effect of PXC on cell apoptosis was detected by using flow cytometry. The suppression of PXC on cell migration and invasion was investigated by chamber assay. To investigate the underlying molecular mechanisms, the expression of proteins related to epithelial to mesenchymal transition(EMT) was analyzed by Western blotting in breast cancer cells and by immunohistochemistry in tumor tissues. The anticancer effect of PXC in vivo was evaluated by using MDA-MB-231 xenograft model and 4T1 metastatic breast cancer model. RESULTS: Our results indicated that triple-negative breast cancer(TNBC) cell lines MDA-MB-231 and MDAMB-468 were sensitive to PXC. PXC potently inhibited the proliferation, colony formation, migration, and invasion of MDA-MB-231 and MDA-MB-468 cells in vitro. Then, in vivo MDA-MB-231 xenograft model depicted that PXC significantly reduced tumor size and weight compared with Control. 4T1 lung metastasis model showed that PXC significantly inhibited breast cancer cell spreading to lungs in mice. Mechanistically, PXC inhibited EMT process by reducing cadherin turnover in TNBC. Furthermore, PXC in combination with 8 Gy X-ray treatment obviously promoted the induction of apoptosis, and suppressed cell proliferation. CONCLUSION: PXC could inhibit the proliferation and invasion of TNBC both in vitro and in vivo, and exerted its anti-metastatic effect by regulating cadherin turnover, Furthermore, it sensitized the TNBC cells to radiotherapy. The data supported further development of PXC as an adjuvant-therapy agent for TNBC.

Liuwei Dihuang pill suppresses metastasis by regulating the wnt pathway and disrupting β-catenin/T cell factor interactions in a murine model of triple-negative breast cancer

OBJECTIVE:To investigate if the Liuwei Dihuang pill(LWDHP)can inhibit metastasis to the liver and lungs in mice bearing triple-negative breast cancer(TNBC),and the molecular mechanism underpinning this action.METHODS:Ninety-nine TNBC bearing-mice were distributed randomly to five groups:control(Con),paclitaxel(PTX),low-dose LWDHP(LLP,2.3 g·kg^-1·d^-1),middle-dose LWDHP(MLP,4.6 g·kg^-1·d^-1)and high-dose LWDHP(HLP,9.2 g·kg^-1·d^-1).The LWDHP were administered(p.o.)to the agonal stage.The morphology of BC cells was observed by hematoxylin&eosin staining.Expression of axin-2,β-catenin,T cell factor(TCF),cyclin-D1 and vascular endothelial growth factor(VEGF)was detected by western blotting or immunofluorescence.β-catenin/TCF-1 interaction was measured using a co-immunoprecipitation assay.RESULTS:After LWDHP treatment,metastasis of BC cells to the lungs and liver was inhibited,expression of axin-2 was increased,expression of TCF-1,β-catenin,cyclin-D1 and VEGF was decreased,andβ-catenin/TCF-1 interaction was disrupted.CONCLUSION:The LWDHP could inhibit metastasis of BC cells to the liver and lungs.The molecular mechanism underlying this action may be regulation of protein expression andβ-catenin/TCF-1 interactions in the Wnt pathway.

Inhibition of MYC suppresses programmed cell death ligand-1 expression and enhances immunotherapy in triple-negative breast cancer

Background:Cancer immunotherapy has emerged as a promising strategy against triple-negative breast cancer(TNBC).One of the immunosuppressive pathways involves programmed cell death-1(PD-1)and programmed cell death ligand-1(PD-L1),but many patients derived little benefit from PD-1/PD-L1 checkpoint blockades treatment.Prior research has shown that MYC,a master transcription amplifier highly expressed in TNBC cells,can regulate the tumor immune microenvironment and constrain the efficacy of immunotherapy.This study aims to investigate the regulatory relationship between MYC and PD-L1,and whether a cyclin-dependent kinase(CDK)inhibitor that inhibits MYC expression in combination with anti-PD-L1 antibodies can enhance the response to immunotherapy.Methods:Public databases and TNBC tissue microarrays were used to study the correlation between MYC and PD-L1.The expression of MYC and PD-L1 in TNBCs was examined by quantitative real-time polymerase chain reaction and Western blotting.A patient-derived tumor xenograft(PDTX)model was used to evaluate the influence of a CDK7 inhibitor THZ1 on PD-L1 expression.Cell proliferation and migration were detected by 5-ethynyl-2′-deoxyuridine(EdU)cell proliferation and cell migration assays.Tumor xenograft models were established for in vivo verification.Results:A high MYC expression level was associated with a poor prognosis and could alter the proportion of tumor-infiltrating immune cells(TIICs).The positive correlation between MYC and PD-L1 was confirmed by immunostaining samples from 165 TNBC patients.Suppression of MYC in TNBC caused a reduction in the levels of both PD-L1 messenger RNA and protein.In addition,antitumor immune response was enhanced in the TNBC cancer xenograft mouse model with suppression of MYC by CDK7 inhibitor THZ1.Conclusions:The combined therapy of CDK7 inhibitor THZ1 and anti-PD-L1 antibody appeared to have a synergistic effect,which might offer new insight for enhancing immunotherapy in TNBC.

Tetrandrine and arsenic trioxide synergistically inhibit proliferation of HCC1937 triple negative breast cancer cells

OBJECTIVE: To evaluate the effects of tetrandrine plus arsenic trioxide on HCC1937 cells, a triple negative breast cancer cell line, and to explore possible mechanisms.METHODS: The 3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide method was used to compare the antiproliferative effects of tetrandrine,arsenic trioxide alone and tetrandrine plus arsenic trioxide on HCC1937 cells. The median-effect principle(Chou-Talalay combination index method) was used to examine the interaction between the two drugs. Flow cytometry was used to evaluate effects of treatment with tetrandrine, arsenic trioxide or the combination of both on HCC1937 cell apoptosis. Real-time polymerase chain reaction and western blotting were performed to evaluate changes in apoptosis-related gene expression and protein levels.RESULTS: Tetrandrine and arsenic trioxide each in-hibited HCC1937 cell proliferation in a dose-dependent manner. The cell inhibition rate of HCC1937 cells treated with a combination of tetrandrine and arsenic trioxide was significantly higher than with either compound alone. The two drugs produced a synergistic effect when the inhibition rate was20%-40%. Flow cytometry results showed that treatment with the two drugs increased the proportion of apoptotic cells. In the combination treated group, caspase-3 activation and PARP cleavage were significantly higher than in the other groups.Moreover, Bcl-2 and survivin expression were decreased, whereas that of both Bid and Bax was increased.CONCLUSION: These findings demonstrated that tetrandrine plus arsenic trioxide had synergistic efficacy on induction of apoptosis in HCC1937 cells.

Effecacy of Biejia(Carapax Trionycis) and Ezhu(Rhizoma Curcumae Phaeocaulis) couplet medicine on epithelial-mesenchymal transition, invasion and migration of MDA-MB-231 triple negative breast cancer cells via PI3K/Akt/mTOR signaling pathway

OBJECTIVE:To investigate the efficacy of Biejia(Carapax Trionycis)and Ezhu(Rhizoma Curcumae Phaeocaulis)couplet medicine on epithelial-mesenchymal transition(EMT),invasion and migration of MDA-MB-231 triple negative breast cancer(TNBC)cells based on PI3K/Akt/mTOR signaling pathway.METHODS:MDA-MB-231 cells were treated with different medicated serum as Biejia-,Ezhu-,Biejia-Ezhu(BJ-,EZ-,BJ-EZ-)groups,intervened with no drug rat serum and paclitaxel with final concentration of 33 nM(IC50)as negative and positive control(NC and PC)groups.CCK-8 assay,scratch test,and Transwell assay were used to examine cell proliferation,invasion,and migration.The expression of E-cadherin,N-cadherin,Vimentin,MMP-2,MMP-9,PI3K,Akt,p-Akt,mTOR,and p-mTOR was determined by Western blot,and the m RNA expression of PI3K,Akt and mTOR was determined by real-time polymerase chain reaction.RESULTS:BJ-EZ group inhibited proliferation after 24,48,and 72 h compared with the NC group(P<0.05,<0.01 or<0.001)and reduced the invasion and migration of MDA-MB-231 cells(P<0.01 or<0.001).In addition,BJ-EZ group upregulated the expression of E-cadherin,downregulated the expression of N-cadherin,Vimentin,MMP-2,and MMP-9(P<0.05,P<0.01 or P<0.001),and inhibited the m RNA and protein expression of PI3K,Akt(p-Akt),mTOR(p-mTOR)(P<0.05,<0.01 or<0.001).CONCLUSION:Biejia(Carapax Trionycis)and Ezhu(Rhizoma Curcumae Phaeocaulis)couplet medicine can inhibit the proliferation,invasion,migration and EMT of MDA-MB-231 cells through PI3K/Akt/mTOR signaling pathway,and the effect is better than that of Biejia(Carapax Trionycis)or Ezhu(Rhizoma Curcumae Phaeocaulis)alone.