Abstract 3869: MicroRNA-200b blocks breast cancer lung metastasis in an orthotopic mouse mammary xenograft tumor model.

Author(s):  
Brock Humphries ◽  
Zhishan Wang ◽  
Chengfeng Yang
2020 ◽  
Author(s):  
Jie Zhang ◽  
Lina Zhang ◽  
Jianlong Wang ◽  
Jing Zhao ◽  
Xuelian Zhao ◽  
...  

Abstract Background: Leucine zipper tumor suppressor 2 (LZTS2), an emerging tumor-suppressor, is attenuated in multiple cancers including prostate, lung and colon cancer. However, its expression and upstream regulatory mechanisms in triple negative breast cancer (TNBC) still remain unknown.Materials and methods: The expression of LZTS2 in TNBC and matched para-carcinoma tissues was detected with immunohistochemistry. The correlations between LZTS2 expression and clinicopathological parameters were analyzed. Kaplan-Meier analysis was performed to determine the prognostic role of LZTS2 for TNBC patients. CCK-8, wound healing and transwell assay were used to detect the effect of LZTS2 overexpression on the proliferation, migration and invasion ability, respectively. The bioinformation algorithms were used to reveal the potential upstream regulatory miRNA. Then, dual-luciferase reporter assay was performed to confirm the regulatory effect of the chosen miRNA on the expression of LZTS2. miR-9-5p inhibitor was used to determine the effect of miR-9-5p on the subcellular localization of β-catenin. Then, western blotting was performed to reveal the effect of miR-9-5p on EMT-related proteins in TNBC cells. Xenograft tumor model was established to reveal the effect of miR-9-5p on TNBC progression in vivo.Results: Low expression of LZTS2 was observed in 62 of 95 cases of TNBC tissue. Low expression of LZTS2 was correlated with poor postoperative DFS and OS of TNBC patients. LZTS2 could inhibit the proliferation, migration and invasion ability of TNBC cells. LZTS2 could be downregulated by miR-9-5p in TNBC, and the nuclear export of β-catenin was suppressed. Consequently, miR-9-5p inhibitor downregulated E-cadherin and upregulated N-cadherin, Twist and Vimentin in TNBC cells. Xenograft tumor model showed that miR-9-5p inhibitor could upregulate the expression of LZTS2 and induce nuclear export of β-catenin in TNBC.Conclusions: miR-9-5p contributes to β-catenin-activated EMT via downregulating LZTS2, and thus promotes TNBC progression.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Weiguang Liu ◽  
Jianjun Han ◽  
Sufang Shi ◽  
Yuna Dai ◽  
Jianchao He

Abstract Background Triple negative breast cancer (TNBC) is a breast cancer (BC) subtype that is characterized by its strong invasion and a high risk of metastasis. However, the specific mechanisms underlying these phenotypes are unclear. TUFT1 plays an important role in BC and impacts the proliferation and survival of BC cells. Recent studies have shown that TUFT1 mediates intracellular lysosome localization and vesicle transport by regulating Rab GTPase, but the relevance of this activity in TNBC is unknown. Therefore, our aim was to systematically study the role of TUFT1 in the metastasis and chemoresistance of TNBC. Methods We measured TUFT1, Rab5-GTP, and Rac1-GTP expression levels in samples of human TNBC by immunohistochemistry (IHC) and conducted univariate and multivariate analyses. shRNA-mediated knockdown and overexpression, combined with transwell assays, co-immunoprecipitation, a nude mouse xenograft tumor model, and GTP activity assays were used for further mechanistic studies. Results TUFT1 expression was positively correlated with Rab5-GTP and Rac1-GTP in the TNBC samples, and co-expression of TUFT1 and Rab5-GTP predicted poor prognosis in TNBC patients who were treated with chemotherapy. Mechanism studies showed that TUFT1 could activate Rab5 by binding to p85α, leading to activation of Rac1 through recruitment of Tiam1, and concurrent down-regulation of the NF-κB pathway and proapoptotic factors, ultimately promoting metastasis and chemoresistance in TNBC cells. Conclusions Our findings suggest that the TUFT1/Rab5/Rac1 pathway may be a potential target for the effective treatment of TNBC.


2020 ◽  
Author(s):  
Margaret L Dahn ◽  
Cheryl A Dean ◽  
Diana B Jo ◽  
Krysta M Coyle ◽  
Paola Marcato

AbstractMetastasis is the primary cause of cancer-related mortality. Having experimental models that accurately reflect changes in the metastatic burden is imperative for developing improved treatments and a better understanding of the disease. The murine xenograft tumor model mimics the human scenario and provides a platform for in vivo and ex vivo metastasis quantification analyses. Histological analysis of hematoxylin and eosin (H&E) stained thin sections has been the gold standard for quantifying metastasis ex vivo but gaining favor for its ease and accuracy is reverse transcription-qualitative polymerase chain reaction (RT-qPCR). Herein we directly compare histological and RT-qPCR-based methods for quantifying lung metastasis in a murine xenograft tumor model. Furthermore, we have introduced a variation of the RT-qPCR method; human-specific glyceraldehyde 3-phosphate dehydrogenase (GAPDH) RT-qPCR, which allows quantification of metastasis in xenograft models, without the requirement of overexpression of exogenous genes. Human-specific GAPDH RT-qPCR detected increased lung metastasis resulting from aldehyde dehydrogenase 1A3 (ALDH1A3) expression in MDA-MB-231 breast cancer cells orthotopically implanted in NOD/SCID mice. Further, in the xenograft tumor model, human-specific GAPDH RT-qPCR was more sensitive and cost-effective than quantification of lung metastasis by histological analysis of H&E stained fixed thin sections. The two assays were highly correlative in terms of determining relative metastatic burden, suggesting that the human-specific GAPDH RT-qPCR method could be used as a standard method for quantification of disseminated human cells in murine xenograft models.


2020 ◽  
Author(s):  
Guangping Wu ◽  
Yuan Luo ◽  
Yusai Xie ◽  
Yang Han ◽  
Di Zhang ◽  
...  

Abstract Background: Wnt5b is noncanonical Wnt ligand, and programmed-death ligand 1 (PD-L1) is a targeted agent for immunotherapy, but the mechanism by which Wnt5b regulates PD-L1 expression in non-small cell lung cancer (NSCLC) is unclear. Methods: Wnt5b and PD-L1 expressions were detected in NSCLC specimens by immunohistochemistry. The interrelationship connecting Wnt5b with PD-L1 was verified using dual-luciferase assay, immunofluorescence, coimmunoprecipitation, western blot,real-time PCR and xenograft tumor model. Results: Wnt5b and PD-L1 expressions were positively correlated in NSCLC specimens. Five-year survival time in the group with their coexpression was significantly lower than that without coexpression. Under the effect of Wnt5b, Frizzled-3 (Fzd3) initiated Dishevellde-3 (Dvl-3) membrane recruitment via DEP domain by Dvl-3 phosphorylation, contributing to activate PCP/JNK signaling through the small GTPase Rac1, and then upregulate PD-L1 expression and promote the malignant phenotype of NSCLC in vivo and in vitro. After PD-L1 antibody treatment, Wnt5b induced tumor growth was inhibited significantly in xenograft tumor model. Conclusion: We demonstrate a new signal transduction pathway: Wnt5b initiates Dvl-3 membrane recruitment via DEP domain by Fzd3 so as to promote Rac1–PCP/JNK–PD-L1 pathway, which provides a potential target for clinical intervention and immunotherapy in lung cancer.


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