Background: N6-methyladenosine (m⁶A) is the most common post-transcriptional modification at the RNA level. However, the exact molecular mechanisms of m6A epigenetic regulation in breast cancer remain largely unknown and need to be fully elucidated. Methods: The integrating bioinformatics analyses were used to screen clinical relevance and dysregulated m6A “reader” protein YTHDF1 in breast cancer from TCGA databases, which was further validated in a cohort of clinical specimens. Furthermore, functional experiments such as the CCK-8 assay, EdU assay, wound healing assay, transwell invasion assay and cell cycle assay were used to determine the biological role of YTHDF1 in breast cancer. RIP, m6A-IP, and CLIP assays were used to find the target of YTHDF1 and further verification by RT-qPCR, western blot, polysome profiling assay. The protein–protein interaction between YTHDF1 and FOXM1 was detected via co-immunoprecipitation. Results: Our study showed that YTHDF1 was overexpressed in breast cancer cells and clinical tissues specimens. At the same time, the high expression level of YTHDF1 was positively correlated with tumor size, lymph node invasion, and distant metastasis in breast cancer patients. YTHDF1 depletion repressed the proliferation, invasion and epithelial-mesenchymal transformation (EMT) and induced G0/G1 phase cell cycle arrest of breast cancer cells in vitro and in vivo. We also demonstrated that FOXM1 is a target of YTHDF1. Through recognizing and binding to the m6A-modified mRNA of FOXM1, YTHDF1 accelerated the translation process of FOXM1 and promoted breast cancer metastasis. Whereas overexpression of FOXM1 in breast cancer cells partially counteracted the tumor suppressed effects caused by YTHDF1 silence, which further verified the regulatory relationship between YTHDF1 and FOXM1. Conclusion: Our study reveals a novel YTHDF1/FOXM1 regulatory pathway that contributes to metastasis and progression of breast cancer, suggesting that YTHDF1 might be applied as a potential biomarker and therapeutic target. That also advances our understanding of the tumorigenesis for breast cancer from m6A epigenetic regulation.

Long noncoding RNAs (lncRNAs) play crucial regulatory roles in the progression of various cancers. However, the functional roles of lncRNAs in breast cancer remain unclear. In this study, we investigated the functional role of a novel long noncoding RNA SEMA3B-AS1 (lncRNA SEAS1) in breast cancer progression and the underlying mechanisms. SEAS1 was downregulated in the triple-negative breast cancer (TNBC) tissues compared with the para-carcinoma tissues, which was associated with poor prognosis of TNBC patients. We demonstrated that SEAS1 knockdown significantly increased the proliferation, migration, and invasion of TNBC cell lines, whereas SEAS1 overexpression reversed these effects. Bioinformatics analysis demonstrated that microRNA (miR)-3940-3p was a potential target of SEAS1. Mechanistically, RNA immunoprecipitation (RIP) and luciferase reporter assays confirmed that lncRNA SEMA3B-AS1 acted as sponge for miR-3940-3p, preventing the degradation of its target gene KLLN, which acts as a tumor-inhibiter in TNBC. Moreover, RNA pulldown, mass spectrometry, ChIP, and luciferase reporter assays confirmed that SMAD3 directly interacted with the promoter of SEAS1 and suppressed its transcription, thereby promoting TNBC progression. The clinical samples of TNBC confirmed SEAS1 was correlated inversely with lymphatic and distant metastasis. In conclusion, our findings reveal a novel pathway for TNBC progression via SMAD3/lncRNA SEAS1/miR-3940-3p/KLLN axis, and suggest that SEAS1 may serve as a potential biomarker and therapeutic target for TNBC.

Increasing evidence suggested DNA methylation may serve as potential prognostic biomarkers; however, few related DNA methylation signatures have been established for prediction of lung cancer prognosis. We aimed at developing DNA methylation signature to improve prognosis prediction of stage I lung adenocarcinoma (LUAD). A total of 268 stage I LUAD patients from the Cancer Genome Atlas (TCGA) database were included. These patients were separated into training and internal validation datasets. GSE39279 was used as an external validation set. A 13‐DNA methylation signature was identified to be crucially relevant to the relapse‐free survival (RFS) of patients with stage I LUAD by the univariate Cox proportional hazard analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis and multivariate Cox proportional hazard analysis in the training dataset. The Kaplan‐Meier analysis indicated that the 13‐DNA methylation signature could significantly distinguish the high‐ and low‐risk patients in entire TCGA dataset, internal validation and external validation datasets. The receiver operating characteristic (ROC) analysis further verified that the 13‐DNA methylation signature had a better value to predict the RFS of stage I LUAD patients in internal validation, external validation and entire TCGA datasets. In addition, a nomogram combining methylomic risk scores with other clinicopathological factors was performed and the result suggested the good predictive value of the nomogram. In conclusion, we successfully built a DNA methylation‐associated nomogram, enabling prediction of the RFS of patients with stage I LUAD.

Overcoming distant metastasis stands as a paramount challenge in enhancing the outcomes of breast cancer treatments. Thus, delving deeper into comprehending the intricate mechanisms underlying breast cancer metastasis becomes imperative, offering potential avenues for pioneering therapeutic approaches. PRMT6, an arginine N-methyltransferase, possesses the ability to methylate both histone and non-histone proteins. It has been reported that methylation of non-histone proteins impacts their cellular localization, stability, and activation, consequently influencing tumor progression. However, the extent to which PRMT6-mediated non-histone protein methylation influences cancer cell metastasis, particularly in the context of breast cancer, remains elusive. In this study, we established that PRMT6 exerted a positive regulatory influence on breast cancer metastasis through both in vivo and in vitro experiments. Mechanistically, we innovatively revealed that PRMT6 asymmetrically di-methylated STAT3 at arginine 729 (STAT3 R729me2a). This modification proved indispensable for STAT3’s membrane localization, its interaction with JAK2, STAT3 Y705 phosphorylation, and PRMT6-driven cancer cell metastasis. From a clinical perspective, we unearthed the promising potential of STAT3 R729me2a as a robust prognostic marker for predicting the overall survival time of breast cancer patients. In terms of therapeutic intervention, we demonstrated the significant capability of the PRMT6 inhibitor, EPZ020411, to curtail breast cancer metastasis both in vivo and in vitro. In sum, our study unveils the pivotal biological role of PRMT6-mediated STAT3 R729me2a in breast cancer metastasis and underscores the prospective utility of PRMT6 inhibitors as effective therapeutic strategies against STAT3-driven metastatic breast cancer.

Mucosal-associated invariant T (MAIT) cells have important functions in immune responses against pathogens and in diseases, but mechanisms controlling MAIT cell development and effector lineage differentiation remain unclear. Here, we report that IL-2/IL-15 receptor β chain and inducible costimulatory (ICOS) not only serve as lineage-specific markers for IFN-γ-producing MAIT1 and IL-17A-producing MAIT17 cells, but are also important for their differentiation, respectively. Both IL-2 and IL-15 induce mTOR activation, T-bet upregulation, and subsequent MAIT cell, especially MAIT1 cell, expansion. By contrast, IL-1β induces more MAIT17 than MAIT1 cells, while IL-23 alone promotes MAIT17 cell proliferation and survival, but synergizes with IL-1β to induce strong MAIT17 cell expansion in an mTOR-dependent manner. Moreover, mTOR is dispensable for early MAIT cell development, yet pivotal for MAIT cell effector differentiation. Our results thus show that mTORC2 integrates signals from ICOS and IL-1βR/IL-23R to exert a crucial role for MAIT17 differentiation, while the IL-2/IL-15R-mTORC1-T-bet axis ensures MAIT1 differentiation.

Background Several agents for oncolytic immunotherapy have been approved for clinical use, but monotherapy is modest for most oncolytic agents. The combination of several therapeutic strategies through recombinant and nanotechnology to engineer multifunctional oncolytic viruses for oncolytic immunotherapy is a promising strategy. Methods An endothelium-targeting iRGD-liposome encapsulating a recombinant Newcastle disease virus (NDV), which expresses the dendritic cell (DC) chemokine MIP-3α (iNDV3α-LP), and three control liposomes were constructed. MIP-3α, HMGB1, IgG, and ATP were detected by western blotting or ELISA. The chemotaxis of DCs was examined by Transwell chambers. The phenotypes of the immune cells were analyzed by flow cytometry. The antitumor efficiency was investigated in B16 and 4T1 tumor-bearing mice. Immunofluorescence and immunohistochemistry were used to observe the localization of liposomes, molecular expression and angiogenesis. Synergistic index was calculated using the data of tumor volume, tumor angiogenesis and tumor-infiltrating lymphocytes. Results Compared with NDV-LP, treatment with iNDV3α-LP and NDV3α-LP induced stronger virus replication and cell lysis in B16 and 4T1 tumor cells and human umbilical vein endothelial cells (HUVECs) with the best response observed following iNDV3α-LP treatment. B16 and 4T1 cells treated with iNDV3α-LP produced more damage-associated molecular pattern molecules, including secreted HMGB1, ATP, and calreticulin. Moreover, iNDV3α-LP specifically bound to αvβ3-expressing 4T1 cells and HUVECs and to tumor neovasculature. Tumor growth was significantly suppressed, and survival was longer in iNDV3α-LP-treated B16-bearing and 4T1-bearing mice. A mechanism study showed that iNDV3α-LP treatment initiated the strongest tumor-specific cellular and humoral immune response. Moreover, iNDV3α-LP treatment could significantly suppress tumor angiogenesis and reverse the tumor immune suppressive microenvironment in both B16-bearing and 4T1-bearing mice. Conclusions In this study, iNDV3α-LP had several functions, such as tumor and vessel lysis, MIP-3α immunotherapy, and binding to αvβ3-expressing tumor and its neovasculature. iNDV3α-LP treatment significantly suppressed tumor angiogenesis and reversed the tumor immunosuppressive microenvironment. These findings offer a strong rationale for further clinical investigation into a combination strategy for oncolytic immunotherapy, such as the formulation iNDV3α-LP in this study.