Cancer metastasis is the cause of the majority of cancer-related deaths. In this study, we demonstrated that no expression or low expression of ATP11B in conjunction with high expression of PTDSS2, which was negatively regulated by BRCA1, markedly accelerates tumor metastasis. Further analysis revealed that cells with low ATP11B expression and high PTDSS2 expression (ATP11BloPTDSS2hi cells) were associated with poor prognosis and enhanced metastasis in breast cancer patients in general. Mechanistically, an ATP11BloPTDSS2hi phenotype was associated with increased levels of nonapoptotic phosphatidylserine (PS) on the outer leaflet of the cell membrane. This PS increase serves as a global immunosuppressive signal to promote breast cancer metastasis through an enriched tumor microenvironment with the accumulation of myeloid-derived suppressor cells and reduced activity of cytotoxic T cells. The metastatic processes associated with ATP11BloPTDSS2hi cancer cells can be effectively overcome by changing the expression phenotype to ATP11BhiPTDSS2lo through a combination of anti-PS antibody with either paclitaxel or docetaxel. Thus, blocking the ATP11BloPTDSS2hi axis provides a new selective therapeutic strategy to prevent metastasis in breast cancer patients.
Excessive drinking poses serious health risks and is closely associated with oxidative damage. The KEAP1-NRF2-ARE axis serves as the primary antioxidant system. However, the existing small molecule inhibitors are all covalently bound to KEAP1, meaning that once bound, they are not easily dissociated, while continuous inhibition of KEAP1 exhibits severe side effects. In this study, BLI, CETSA, Pull-down, Co-IP and HDX-MS assay analysis were conducted to detect the KEAP1 binding behavior of natural product, capsaicin (CAP), both in vitro and in GES1 cells. The ethanol-induced acute gastric mucosal damage rat model was also established to determine the therapeutic effect of CAP. We demonstrated that CAP ameliorated mitochondrial damage, facilitated the nuclear translocation of NRF2, thereby promoting the expression of downstream antioxidant response elements, HO-1, Trx, GSS and NQO1 in GES1 cells. Subsequently, CAP could directly bind to KEAP1 and inhibit the interaction between KEAP1 and NRF2. While in the KEAP1-knockout 293T cells, CAP failed to activate NRF2 expression. It was also found that CAP non-covalently bound to Kelch domain and allosterically regulated three regions of KEAP1: L342-L355, D394-G423 and N482-N495. To enhance drug solubility and delivery efficiency, we designed IR-Dye800 modified albumin coated CAP nanoparticle. The nanoparticles significantly alleviated the gastric mucosal inflammation and activated the NRF2 downstream genes in vivo. Our work provided new insights that CAP is a safe and novel NRF2 agonist by allosterically regulating KEAP1, which may contribute to the development of lead drugs for oxidative stress-related illness, e.g. aging, cancer, neurodegenerative and cardiovascular diseases.
Recipient preparation is of prime importance for the successful transplantation of spermatogonial stem cells (SSCs).Busulfan destroys endogenous germs cells and is commonly used for recipient preparation.However, busulfan produces significant side effects, including systemic toxicity, and it is lethal in certain species.The side effects associated with busulfan compromise the efficiency of SSC transplantation and threaten the safety of recipients.Here, we show that heat shock treatment of testes can be used as an alternative to busulfan treatment.Fourteen days after heat shock treatment, mice received a testicular injection of donor germ cells expressing enhanced green fluorescent protein (EGFP).Busulfan-treated mice were used as controls.Two months after transplantation, the number (12 6 1 mm) and length (30.46 6 5.23 mm) of EGFP-expressing testicular colonies in heat shock-treated recipients were not significantly different from those in busulfan-treated recipients.Furthermore, healthy EGFP-expressing offspring were obtained after intracytoplasmic injection of round spermatids recovered from heat shock-treated recipients.This result indicates that donor SSCs undergo complete spermatogenesis in the heat shock-treated testes of recipients.Our findings demonstrate the feasibility of using heat shock for the preparation of recipients before SSC transplantation in mice.Heat shock may prove to be useful for recipient preparation in mammalian species in which busulfan produces significant toxicity.apoptosis, busulfan, heat shock, recipient, Sertoli cells, sperm, spermatid,
Well-orchestrated epigenetic modifications during early development are essential for embryonic survival and postnatal growth. Erroneous epigenetic modifications due to environmental perturbations such as manipulation and culture of embryos during in vitro fertilization (IVF) are linked to various short- or long-term consequences. Among these, DNA methylation defects are of great concern. Despite the critical role of DNA methylation in determining embryonic development potential, the mechanisms underlying IVF-associated DNA methylation defects, however, remains largely elusive. We reported herein that repression of fibroblast growth factor (FGF) signaling as the main reason for IVF-associated DNA methylation defects. Comparative methylome analysis by postimplantation stage suggested that IVF mouse embryos undergo impaired de novo DNA methylation during implantation stage. Further analyses indicated that Dnmt3b, the main de novo DNA methyltransferase, was consistently inhibited during the transition from the blastocyst to postimplantation stage (Embryonic day 7.5, E7.5). Using blastocysts and embryonic stem cells (ESCs) as the model, we showed repression of FGF signaling is responsible for Dnmt3b inhibition and global hypomethylation during early development, and MEK/ERK-SP1 pathway plays an essential mediating role in FGF signaling-induced transcriptional activation of Dnmt3b. Supplementation of FGF2, which was exclusively produced in the maternal oviduct, into embryo culture medium significantly rescued Dnmt3b inhibition. Our study, using mouse embryos as the model, not only identifies FGF signaling as the main target for correcting IVF-associated epigenetic errors, but also highlights the importance of oviductal paracrine factors in supporting early embryonic development and improving in vitro culture system.
Background: BRCA1 plays critical roles in mammary gland development and mammary tumorigenesis. And loss of BRCA1 induces mammary tumors in a stochastic manner. These tumors present great heterogeneity at both intertumor and intratumor levels. Methods: To comprehensively elucidate the heterogeneity of BRCA1 deficient mammary tumors and the underlying mechanisms for tumor initiation and progression, we conducted bulk and single cell RNA sequencing (scRNA-seq) on both mammary gland cells and mammary tumor cells isolated from Brca1 knockout mice. Results: We found the BRCA1 deficient tumors could be classified into four subtypes with distinct molecular features and different sensitivities to anti-cancer drugs at the intertumor level. Whereas within the tumors, heterogeneous subgroups were classified mainly due to the different activities of cell proliferation, DNA damage response/repair and epithelial-to-mesenchymal transition (EMT). Besides, we reconstructed the BRCA1 related mammary tumorigenesis to uncover the transcriptomes alterations during this process via pseudo-temporal analysis of the scRNA-seq data. Furthermore, from candidate markers for BRCA1 mutant tumors, we discovered and validated one oncogene Mrc2, whose loss could reduce mammary tumor growth in vitro and in vivo. Conclusion: Our study provides a useful resource for better understanding of mammary tumorigenesis induced by BRCA1 deficiency.
Resistance to therapeutic drugs occurs in virtually all types of cancers, and the tolerance to one drug frequently becomes broad therapy resistance; however, the underlying mechanism remains elusive. Combining a whole whole-genome-wide RNA interference screening and an evolutionary drug pressure model with MDA-MB-231 cells, it is found that enhanced protein damage clearance and reduced mitochondrial respiratory activity are responsible for cisplatin resistance. Screening drug-resistant cancer cells and human patient-derived organoids for breast and colon cancers with many anticancer drugs indicates that activation of mitochondrion protein import surveillance system enhances proteasome activity and minimizes caspase activation, leading to broad drug resistance that can be overcome by co-treatment with a proteasome inhibitor, bortezomib. It is further demonstrated that cisplatin and bortezomib encapsulated into nanoparticle further enhance their therapeutic efficacy and alleviate side effects induced by drug combination treatment. These data demonstrate a feasibility for eliminating broad drug resistance by targeting its common mechanism to achieve effective therapy for multiple cancers.
Abstract Well-orchestrated maternal-fetal crosstalk occurs via secreted ligands, interacting receptors, and coupled intracellular pathways between the conceptus and endometrium, and is essential for successful embryo implantation. However, previous studies mostly focus on either the conceptus or the endometrium in isolation. The lack of integrated analysis impedes our understanding of early maternal-fetal crosstalk. Herein, focusing on ligand–receptor complexes and coupled pathways at the maternal-fetal interface in sheep, we provide the first comprehensive proteomic map of ligand-receptor pathway cascades essential for embryo implantation. We demonstrate that these cascades are associated with cell adhesion and invasion, redox homeostasis, and the immune response. Candidate interactions and their physiological roles were further validated by functional experiments. We reveal the physical interaction of albumin and claudin 4 and their roles in facilitating embryo attachment to endometrium. We also demonstrate a novel function of enhanced conceptus glycolysis in remodeling uterine receptivity by inducing endometrial histone lactylation, a newly identified histone modification. Results from in vitro and in vivo models supported the essential role of lactate in inducing endometrial H3K18 lactylation and in regulating redox homeostasis and apoptotic balance to ensure successful implantation. By reconstructing a map of potential ligand-receptor pathway cascades at the maternal-fetal interface, our study presents new concepts for understanding molecular and cellular mechanisms that fine-tune conceptus-endometrium crosstalk during implantation. This provides more direct and accurate insights for developing potential clinical intervention strategies to improve pregnancy outcomes following both natural and assisted conception.
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