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Background: Tumor microenvironment actually reduces antitumor effect against the immune attack by exclusion of CD8+T cells. Progranulin (PGRN) is a multifunctional growth factor with significant pathological effects in multiple tumors; however, its role in immunity evasion of breast cancer (BCa) is not completely understood. Methods: We depleted GRN (PGRN gene) genetically in mice or specifically in PY8119 murine BCa cell line, and mouse models of orthotopic or subcutaneous transplantation were used. Chimeric mice-deficient of PGRN (Grn−/−) in bone marrow (BM) compartment was also generated. Association of PGRN expression with chemokine production or BCa development was investigated by histological and immunological assays. Results: We found PGRN was involved in exhaustion of cytotoxic CD8+T cell in BCa with the increasing expressions of M2 markers and intercellular cell adhesion molecule-1 (ICAM-1) on macrophages. Specifically, ablation of PGRN in PY8119 cells reduced tumor burden, accompanied by the infiltrating of cytotoxic CD8+T cells into tumor nests. Moreover, our result revealed that blockade of PD-1 in PGRN-depleted tumors exhibited better antitumor effect in vivo and significantly decreased tumor burden. Conclusion: These findings suggest that inhibition of PGRN may act as a potential immune-therapeutic strategy by recovering infiltration of CD8+T cell in BCa tissue and thereby enhancing the response to anti-PD-1 therapy. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignancy among women worldwide. Functional studies have demonstrated that miRNA dysregulation in many cases of cancer, in which miRNAs act as either oncogenes or tumor suppressor. Here we report that miR-345-3p is generally upregulated in breast cancer tissues and breast cancer cell lines. Overexpression and inhibition of miR-345-3p revealed its capacity in regulating proliferation and invasion of breast cancer cells. Further research identified protein phosphatase 2 catalytic subunit alpha (PPP2CA), a suppressor of AKT phosphorylation, as a candidate target of miR-345-3p. In vitro , miR-345-3p mimics promoted AKT phosphorylation by targeting its negative regulator, PPP2CA. Blocking miR-345-3p relieved its inhibition of PPP2CA, which attenuated PI3K-AKT signaling pathway. In vivo , inhibiting miR-345-3p by miR-345-3p-inhibition lentivirus suppressed tumor growth and invasiveness in mice. Together, the miR-345-3p/PPP2CA signaling axis exhibits tumor-promoting functions by regulating proliferation and invasion of breast cancer cells. These data provide a clue to novel therapeutic approaches for breast cancer. [ABSTRACT FROM AUTHOR]

In this study, a novel electrochemical biosensor was constructed for ultrasensitive and locus-specific detection of N6-Methyladenine (m6A) in DNA using double-hindered replication and nucleic acid-coated methylene blue (MB)@Zr-MOF. Based on the combination of m6A-impeded replication and AgI-mediated mismatch replication, this mode could effectively stop the extension of the strand once DNA polymerase encountered m6A site, which specifically distinguish the m6A site from natural A site in DNA. Also, Zr-MOF with high porosity and negative surface potential features was carefully chose to load cationic MB, resulting a stable and robust MB@Zr-MOF electrochemical tag. As a result, the developed biosensor exhibited a wide linear range from 1 fM to 1 nM with detection limit down to 0.89 fM. Profiting from the high sensitivity and selectivity, the biosensing strategy revealed good applicability, which had been demonstrated by quantitating m6A DNA at specific site in biological matrix. Thus, the biosensor provides a promising platform for locus-specific m6A DNA analysis. [ABSTRACT FROM AUTHOR]

Pyruvate dehydrogenase kinase 1 (PDK1) phosphorylates the pyruvate dehydrogenase complex, which inhibits its activity. Inhibiting pyruvate dehydrogenase complex inhibits the tricarboxylic acid cycle and the reprogramming of tumor cell metabolism to glycolysis, which plays an important role in tumor progression. This study aims to elucidate how PDK1 promotes breast cancer progression. We found that PDK1 was highly expressed in breast cancer tissues, and PDK1 knockdown reduced the proliferation, migration, and tumorigenicity of breast cancer cells and inhibited the HIF-1α (hypoxia-inducible factor 1α) pathway. Further investigation showed that PDK1 promoted the protein stability of HIF-1α by reducing the level of ubiquitination of HIF-1α. The HIF-1α protein levels were dependent on PDK1 kinase activity. Furthermore, HIF-1α phosphorylation at serine 451 was detected in wild-type breast cancer cells but not in PDK1 knockout breast cancer cells. The phosphorylation of HIF-1α at Ser 451 stabilized its protein levels by inhibiting the interaction of HIF-1α with von Hippel-Lindau and prolyl hydroxylase domain. We also found that PDK1 enhanced HIF-1α transcriptional activity. In summary, PDK1 enhances HIF-1α protein stability by phosphorylating HIF-1α at Ser451 and promotes HIF-1α transcriptional activity by enhancing the binding of HIF-1α to P300. PDK1 and HIF-1α form a positive feedback loop to promote breast cancer progression., (© 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.)

Breast cancer is the most common malignancy among women worldwide. Functional studies have demonstrated that miRNA dysregulation in many cases of cancer, in which miRNAs act as either oncogenes or tumor suppressor. Here we report that miR-345-3p is generally upregulated in breast cancer tissues and breast cancer cell lines. Overexpression and inhibition of miR-345-3p revealed its capacity in regulating proliferation and invasion of breast cancer cells. Further research identified protein phosphatase 2 catalytic subunit alpha (PPP2CA), a suppressor of AKT phosphorylation, as a candidate target of miR-345-3p. In vitro, miR-345-3p mimics promoted AKT phosphorylation by targeting its negative regulator, PPP2CA. Blocking miR-345-3p relieved its inhibition of PPP2CA, which attenuated PI3K-AKT signaling pathway. In vivo, inhibiting miR-345-3p by miR-345-3p-inhibition lentivirus suppressed tumor growth and invasiveness in mice. Together, the miR-345-3p/PPP2CA signaling axis exhibits tumor-promoting functions by regulating proliferation and invasion of breast cancer cells. These data provide a clue to novel therapeutic approaches for breast cancer., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective To investigate the effect of progranulin (PGRN) on the invasion and migration of mouse breast cancer 4T1 cells and its mechanism. Methods After treated with PGRN (1 μg/mL) for 24 hours, the invasion ability of breast cancer 4T1 cells was detected by Transwell TM invasion assay, the migration ability was detected by scratch test, and the epithelial cadherin (E-cadherin), vimentin mRNA expression was detected by real-time fluorescent quantitative PCR. Western blot assay was used to detect the expression of E-cadherin, vimentin, extracellular signal-regulated kinase 1/2 (ERK1/2) and phosphorylated ERK1/2 (p-ERK1/2). After treated with 1 μg/mL PGRN and ERK1/2 signaling pathway inhibitor U0126 (10 μmol/L) simultaneously, the migration and invasion ability of 4T1 cells and the changes in the expression of E-cadherin, vimentin and p-ERK proteins were detected again. Results After treated with PGRN, the migration and invasion capabilities of breast cancer 4T1 cells were significantly enhanced; E-cadherin expression decreased; vimentin and p-ERK1/2 expression increased. After treated with ERK1/2 signaling pathway inhibitor, the ability of PGRN to promote breast cancer 4T1 cell migration, invasion and epithelial-mesenchymal transition (EMT) was significantly inhibited. Conclusion PGRN can promote the migration and invasion of breast cancer 4T1 cells by promoting EMT and activating the ERK1/2 pathway.

Objective To explore the functions and mechanisms of macrophages derived from PGRN gene knockout (PGRN -/- ) C57BL/6 mice in the invasion and migration of breast cancer cells. Methods Breast cancer cells were cultured in conditioned medium of macrophages derived from WT and PGRN -/- mice. Transwell TM assay and scratch assay were used to detect the invasion and migration ability of cancer cells. Western blot analysis was used to detect the expression of E-cadherin and N-cadherin in cancer cells. Cytokine array, real-time quantitative PCR and ELISA were performed to investigate the differences of cytokines secreted by macrophages derived from WT and PGRN -/- mice. Breast cancer cells were treated by the differentially expressed cytokine interleukin-6 (IL-6), and then the above methods were used to investigate its effect on cancer cells. Western blot analysis was used to verify the roles of NF-κB and JAK/STAT3 signaling pathways. Results The macrophages derived from PGRN -/- mice blocked NF-κB signaling pathway, reduced IL-6 secretion, and inhibited the invasion and migration of breast cancer cells. IL-6 activated JAK/STAT3 signaling pathway to promote the invasion and migration of breast cancer cells. Conclusion The macrophages derived from PGRN -/- mice can block the NF-κB and JAK/STAT3 signaling pathways, down-regulate IL-6 expression, and inhibit the invasion and migration of breast cancer cells.