In the clinic, anti-tumor angiogenesis is commonly employed for treating recurrent, metastatic, drug-resistant triple-negative, and advanced breast cancer. Our previous research revealed that the deubiquitinase STAMBPL1 enhances the stability of MKP-1, thereby promoting cisplatin resistance in breast cancer. In this study, we discovered that STAMBPL1 could upregulate the expression of the hypoxia-inducible factor HIF1α in breast cancer cells. Therefore, we investigated whether STAMBPL1 promotes tumor angiogenesis. We demonstrated that STAMBPL1 increased HIF1A transcription in a non-enzymatic manner, thereby activating the HIF1α/VEGFA signaling pathway to facilitate triple-negative breast cancer angiogenesis. Through RNA-seq analysis, we identified the transcription factor GRHL3 as a downstream target of STAMBPL1 that is responsible for mediating HIF1A transcription. Furthermore, we discovered that STAMBPL1 regulates GRHL3 transcription by interacting with the transcription factor FOXO1. These findings shed light on the role and mechanism of STAMBPL1 in the pathogenesis of breast cancer, offering novel targets and avenues for the treatment of triple-negative and advanced breast cancer.

Oncolytic viruses (OVs) represent a cutting-edge approach to cancer immunotherapy, characterized by their ability to selectively infect and eliminate tumor cells while sparing healthy tissues. Among the diverse OVs, type 1 herpes simplex virus (HSV-1) stands out due to its robust oncolytic activity, genetic malleability, broad cell tropism, and well-documented clinical safety. Advances in genetic engineering have further amplified the therapeutic efficacy of HSV-1 by enhancing tumor specificity, replication efficiency, and immunogenicity. Clinically significant HSV-1-based oncolytic viruses, such as T-VEC and G47Δ, have gained regulatory approvals for treating melanoma and malignant glioma, respectively, highlighting their transformative potential in cancer therapy. The attenuation strategies employed in most oncolytic HSV-1 (oHSV-1) strains, while ensuring safety, often reduce viral replication and cytotoxicity. To address this limitation, retargeting strategies focusing on HSV-1 glycoproteins (gD, gH/gL, and gB) have been developed. These modifications aim to abolish canonical receptor interactions and achieve tumor-specific targeting through ligand-receptor binding. Recent breakthroughs in understanding HSV entry mechanisms have enabled the creation of fully retargeted HSV vectors with enhanced specificity and efficacy. This review explores the molecular mechanisms underlying HSV glycoprotein-mediated cell entry, examines recent advances in receptor-retargeted oHSV-1 engineering, and discusses the challenges and future directions in the development of oncolytic HSV-based therapies.

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer that lacks reliable targets for diagnosis and therapy. Non-coding RNA (ncRNA)-encoded products hold promise for addressing this unmet need. By analyzing the reported ribosomal RNA sequencing data, combined with the TCGA, ORFfinder, SmProt databases, we identified CDKN2B-AS1, a TNBC-upregulated lncRNA encoding a 66-amino-acid peptide via CUG-initiated translation. CRISPR-Cas9 gene editing and mass spectrometry confirmed endogenous expression of this peptide, designated 66CTG, in TNBC cells. Functionally independently of its host RNA, 66CTG promoted the proliferation of TNBC cells and the tumor growth of TNBC xenograft by stabilizing c-Myc protein and enhancing Cyclin D1 transcription. Immunohistochemistry of 89 clinical TNBC paraffin samples revealed positive correlations among 66CTG, c-Myc, and Cyclin D1 expression levels. Mechanistically, co-immunoprecipitation and ubiquitination assays revealed that 66CTG stabilized c-Myc by competitively interacting with FBW7α, an E3 ligase responsible for recognizing 66CTG CPDS56/S60 motif which phosphorylated by GSK-3β during the late G1 phase. In conclusion, our findings suggest 66CTG has potential to be developed as a target for TNBC diagnosis and therapy. Furthermore, it unveils a regulatory axis wherein 66CTG stabilizes c-Myc by interacting with FBW7α, offering a new mechanistic explanation for c-Myc overexpression in TNBC. Patients co-overexpressing 66CTG, c-Myc, and Cyclin D1 may benefit from therapies targeting this axis.

Basal-like breast cancer (BLBC), overlapping with the subgroup of estrogen receptor (ER), progesterone receptor (PR), and HER2 triple-negative breast cancer, has the worst prognosis and limited therapeutics. The XPO1 gene encodes nuclear export protein 1, a promising anticancer target which mediates nucleus-cytoplasm transport of nuclear export signal containing proteins such as tumor suppressor RB1 and some RNAs. Despite drugs targeting XPO1 are used in clinical, the regulation of XPO1 expression and functional mechanism is poorly understood, especially in BLBC. This study finds that KLF5 is a transcription factor of XPO1, which increases RB1 nuclear export and cell proliferation in BLBC cells. Furthermore, XPO1 interacts with the RNA-binding protein PTBP1 to export FOXO1 mRNA to cytoplasm and thus activates the FOXO1-KLF5 axis as a feedback. This work demonstrates that XPO1 inhibitor KPT-330 in combination with CDK4/6 inhibitor additively suppressed BLBC tumor growth in vivo. These results reveal a novel positive feedback regulation loop between KLF5 and XPO1 and provide a novel treatment strategy for BLBC.

Breast cancer stem cells (BCSCs) are recognized as a critical subpopulation involved in cancer recurrence and metastasis, as they are capable of self-renewal and differentiate into various cell types. BCSCs play significant roles in tumor progression, being regulated by key signaling pathways such as Notch, PI3K/AKT/mTOR, and Hedgehog, and their interactions with the tumor microenvironment, which affect tumor growth and resistance to therapeutics. This review focuses on the surface markers of BCSCs, their roles in recurrence and metastasis, and the key signaling pathways. It also discusses the recent progress in understanding how BCSCs contribute to drug resistance and explores potential therapeutic strategies targeting these cells and their microenvironment to improve clinical outcomes and prevent relapse.

Interest in the use of proteolysis-targeting chimeras (PROTACs) in cancer therapy has increased in recent years. Targeting bromodomain and extra terminal domain (BET) proteins, especially bromodomain-containing protein 4 (BRD4), has shown inhibitory effects on basal-like breast cancer (BLBC). However, the bioavailability of BRD4 PROTACs is restricted by their non-selective biodegradabilityand low tumor-targeting ability. We demonstrated that 6b (BRD4 PROTAC) suppresses BLBC cell growth by targeting BRD4, but not BRD2 and BRD3, for cereblon (CRBN)-mediated ubiquitination and proteasomal degradation. Compound 6b also inhibited expression of Krüppel-like factor 5 (KLF5) transcription factor, a key oncoprotein in BLBC, controlled by BRD4-mediated super-enhancers. Moreover, 6b inhibited HCC1806 tumor growth in a xenograft mouse model. The combination of 6b and KLF5 inhibitors showed additive effects on BLBC. These results suggest that BRD4-specific PROTAC can effectively inhibit BLBC by downregulating KLF5, and that 6b has potential as a novel therapeutic drug for BLBC.

Ataxia-telangiectasia (A-T) is a hereditary neurodegenerative disorder caused by mutations in the ATM (ataxia-telangiectasia mutated) gene. Although existing rodent models reproduce some of the multi-systemic features of A-T, they notably fail to recapitulate the severe neurological manifestations, particularly the profound cerebellar atrophy and associated ataxia. To address this limitation, we have generated ATM-deficient rhesus macaques using CRISPR-Cas9. These macaques exhibit hallmark features of A-T, including growth retardation, lymphopenia, elevated a-fetoprotein levels, oculocutaneous telangiectasias, heightened sensitivity to ionizing radiation, and most critically, cerebellar atrophy, Purkinje cell loss, and early-stage cerebellar neurodegeneration leading to significant motor impairments. Single-nucleus transcriptomic profiling of the cerebellum revealed pronounced gene expression changes associated with ATM deficiency, particularly in molecular layer interneurons (MLIs), which are implicated in Purkinje cell loss. This non-human primate model provides deeper insights into the pathogenesis of A-T and represents a promising and valuable platform for developing therapeutic strategies.

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Breast cancer stem cells (BCSCs) are believed to play a crucial role in the carcinogenesis, therapy resistance, and metastasis of TNBC. It is well known that inflammation promotes stemness. Several studies have identified breast cancer-associated gene 2 (BCA2) as a potential risk factor for breast cancer incidence and prognosis. However, whether and how BCA2 promotes BCSCs has not been elucidated. Here, we demonstrated that BCA2 specifically promotes lipopolysaccharide (LPS)-induced BCSCs through LPS induced SOX9 expression. BCA2 enhances the interaction between myeloid differentiation primary response protein 88 (MyD88) and Toll-like receptor 4 (TLR4) and inhibits the interaction of MyD88 with deubiquitinase OTUD4 in the LPS-mediated NF-κB signaling pathway. And SOX9, an NF-κB target gene, mediates BCA2's pro-stemness function in TNBC. Our findings provide new insights into the molecular mechanisms by which BCA2 promotes breast cancer and potential therapeutic targets for the treatment of breast cancer.

Anti-angiogenesis is a crucial therapeutic strategy for triple-negative breast cancer (TNBC), but the current targeted drugs are insufficient to meet clinical requirements. Our study has discovered that silencing the deubiquitinating enzyme STAMBPL1 can effectively inhibit the growth and angiogenesis of TNBC xenografts in nude mice. STAMBPL1 promotes the expression of HIF1α/VEGFA in TNBC through a non-enzymatic-dependent mechanism. STAMBPL1 interacts with the transcription factor FOXO1, which binds to the promoter of the GRHL3 gene, thereby positively regulating its transcription. Subsequently, GRHL3 binds to the HIF1α gene promoter to promote its transcription and angiogenesis. Moreover, we have demonstrated that the combination of FOXO1 inhibitor AS1842856 and VEGFR inhibitor Apatinib significantly inhibited the growth of transplanted tumors in nude mice. These findings indicate that the STAMBPL1/FOXO1/GRHL3/HIF1α/VEGFA axis provides potential therapeutic targets in TNBC.

Although anti-HER2 therapy has made significant strides in reducing metastasis and relapse in HER2-positive breast cancer, resistance to agents like trastuzumab, pertuzumab, and lapatinib frequently develops in patients undergoing treatment. Previous studies suggest that the hyperactivation of the PI3K-AKT signaling pathway by PIK3CA/PTEN gene mutations is implicated in HER2 resistance. In this study, we introduce a novel PI3K-p110α Proteolysis TAargeting Chimera (PROTAC) that effectively inhibits the proliferation of breast cancer cells by degrading PI3K-p110α. When tested in two lapatinib-resistant cell lines, JIMT1 and MDA-MB-453, both of which harbor PIK3CA mutations, the PI3K PROTAC notably reduced cell proliferation and induced G1 phase cell cycle arrest. Importantly, even at very low concentrations, PI3K PROTAC restored sensitivity to lapatinib. Furthermore, the efficacy of PI3K PROTAC surpassed that of Alpelisib, a selective PI3K-p110α kinase inhibitor in clinic. The superior performance of PI3K PROTAC was also confirmed in lapatinib-resistant breast cancer xenograft tumors and patient-derived breast cancer organoids (PDOs). In conclusion, this study reveals that the novel PI3K PROTAC we synthesized could serve as an effective agent to overcome lapatinib resistance.

Breast cancer (BC) exhibits remarkable heterogeneity. However, the transcriptomic heterogeneity of BC at the single-cell level has not been fully elucidated. We acquired BC samples from 14 patients. Single-cell RNA sequencing (scRNA-seq), bioinformatic analyses, along with immunohistochemistry (IHC) and immunofluorescence (IF) assays were carried out. According to the scRNA-seq results, 10 different cell types were identified. We found that Cancer-Associated Fibroblasts (CAFs) exhibited distinct biological functions and may promote resistance to therapy. Metabolic analysis of tumor cells revealed heterogeneity in glycolysis, gluconeogenesis, and fatty acid synthetase reprogramming, which led to chemotherapy resistance. Furthermore, patients with multiple metastases and progression were predicted to benefit from immunotherapy based on a heterogeneity analysis of T cells and tumor cells. Our findings provide a comprehensive understanding of the heterogeneity of BC, provide comprehensive insight into the correlation between cancer metabolism and chemotherapy resistance, and enable the prediction of immunotherapy responses based on T-cell heterogeneity.

Triple negative breast cancer is the most malignant subtype of breast cancer and current treatment options are limited. Radiotherapy is one of the primary therapeutic options for patients with TNBC. In this study, we discovered that the E3 ubiquitin ligase, HECTD3, promoted TNBC cell survival after irradiation. HECTD3 collaborated with UbcH5b to promote p62 ubiquitination and autophagy while HECTD3 deletion led to p62 accumulation in the nucleus in response to irradiation, thus inhibiting RNF168 mediated DNA damage repair. Furthermore, the HECTD3/UbcH5b inhibitor, PC3-15, increased the radiosensitivity of TNBC cells by inhibiting DNA damage repair. Taken together, we conclude that HECTD3 promotes autophagy and DNA damage repair in response to irradiation in a p62-denpendent manner, and that inhibition of the HECTD3-p62 axis could be a potential therapeutic strategy for patients with TNBC in addition to radiotherapy.

Most basal-like breast cancers(BLBCs)have a poor prog-nosis and high crossover with triple-negative breast cancers(TNBCs).However,approximately 50％of TNBC patients develop chemoresistance.1 Dexamethasone reportedly in-duces Krüppel-like factor 5(KLF5)and can cause docetaxel and cisplatin resistance in TNBC.A super-enhancer can maintain the transcription of KLF5.2 Bromodomain-con-taining 4(BRD4)is a transcriptional coactivator in super-enhancers,and the BRD4 inhibitor compound 870 could strongly inhibit KLF5 transcription.2 Forkhead box class O 1(FOXO1)promotes chemoresistance to doxorubicin in breast cancer.3 FOXO1 has been shown to promote SOX2 transcription,which plays a critical role in cancer stemness.4 In addition,FOXO1 promoted KLF5 transcription in diabetic cardiomyopathy.5 However,the roles of FOXO1 and KLF5 in chemotherapy remain exclusive.In the present study,we examined the function of FOXO1 and the rela-tionship between FOXO1 and KLF5 in BLBCs.We used epi-rubicin(EPI)and cisplatin(DDP)to treat BLBCs.The expression of FOXO1 and KLF5 was down-regulated,whereas KLF5 overexpression decreased the sensitivity of BLBCs to these drugs.FOXO1 regulated KLF5 in the BLBC chemotherapy response,and a novel therapeutic strategy targeting KLF5 and FOXO1 was proposed.

INTRODUCTION:Homologous recombination repair during meiosis is essential for the exchange of genetic information between sister chromosomes, underpinning spermatogenesis and, consequently, fertility. The disruption of this process can lead to infertility, highlighting the importance of identifying the molecular actors involved. OBJECTIVES:This study aims to elucidate the role of the E3 ubiquitin ligase Rnf126 in spermatogenesis and its impact on fertility, particularly through its involvement in meiotic homologous recombination repair. METHODS:We used heterozygous and homozygous Rnf126 deletion models in mouse testes to examine the consequences on testicular health, sperm count, and the process of spermatogenesis. Additionally, we explored the association between RNF126 gene missense variants and nonobstructive male infertility in patients, with a focus on their functional impact on the protein's ubiquitin ligase activity. RESULTS:Rnf126 deletion led to testicular atrophy, disrupted seminiferous tubule structure, reduced sperm count, and spermatogenesis arrest at meiotic prophase I. Furthermore, male mice exhibited impaired homologous recombination repair and increased apoptosis within the seminiferous tubules. We identified four missense variants of the RNF126 (V68M, R241H, E261A, D253N) associated with male infertility. Specifically, the E261A and D253N variants, located in the RING domain, directly compromised the E3 ubiquitin ligase activity of RNF126. CONCLUSION:Our findings demonstrate the pivotal role of RNF126 in maintaining spermatogenesis and fertility, offering insights into the molecular mechanisms underlying male infertility. The identified RNF126 variants present novel targets for diagnostic and therapeutic strategies in treating nonobstructive male infertility.

Breast cancer stem cells are mainly responsible for poor prognosis, especially in triple-negative breast cancer (TNBC). In a previous study, we demonstrated that ε-Sarcoglycan (SGCE), a type Ⅰ single-transmembrane protein, is a potential oncogene that promotes TNBC stemness by stabilizing EGFR. Here, we further found that SGCE depletion reduces breast cancer stem cells, partially through inhibiting the transcription of FGF-BP1, a secreted oncoprotein. Mechanistically, we demonstrate that SGCE could interact with the specific protein 1 transcription factor and translocate into the nucleus, which leads to an increase in the transcription of FGF-BP1, and the secreted FBF-BP1 activates FGF-FGFR signaling to promote cancer cell stemness. The novel SGCE-Sp1-FGF-BP1 axis provides novel potential candidate diagnostic markers and therapeutic targets for TNBC.

Ephrin type-A receptor 2 (EphA2) is a member of the tyrosine receptor kinases, a family of membrane proteins recognized as potential anticancer targets. EphA2 highly expressed in a variety of human cancers, playing roles in proliferation, migration, and invasion. However, whether and how EphA2 regulates basal-like breast cancer (BLBC) cell stemness and chemoresistance has not been revealed. Here, KLF5 was proven to be a direct transcription factor for EphA2 in BLBC cells, and its expression was positively correlated in clinical samples from breast cancer patients. The inflammatory factor TNF-α could promote BLBC cell stemness partially by activating the KLF5-EphA2 axis. Moreover, phosphorylation of EphA2 at S897 (EphA2 pS897) induced by TNF-α and PTX/DDP contributes to chemoresistance of BLBC. Furthermore, the EphA2 inhibitor ALW-II-41-27 could effectively reduce EphA2 pS897 and tumor cell stemness in vitro and significantly enhance the sensitivity of xenografts to the chemotherapeutic drugs PTX and DDP in vivo. Clinically, tumor samples from breast patients with less response to neoadjuvant chemotherapy showed a high level of EphA2 pS897 expression. In conclusion, KLF5-EphA2 promotes stemness and drug resistance in BLBC and could be a potential target for the treatment of BLBC.

Triple negative breast cancer is the most malignant subtype of breast cancer and current treatment options are limited. Radiotherapy is one of the primary therapeutic options for patients with TNBC. In this study, we discovered that the E3 ubiquitin ligase, HECTD3, promoted TNBC cell survival after irradiation. HECTD3 collaborated with UbcH5b to promote p62 ubiquitination and autophagy while HECTD3 deletion led to p62 accumulation in the nucleus in response to irradiation, thus inhibiting RNF168 mediated DNA damage repair. Furthermore, the HECTD3/UbcH5b inhibitor, PC3-15, increased the radiosensitivity of TNBC cells by inhibiting DNA damage repair. Taken together, we conclude that HECTD3 promotes autophagy and DNA damage repair in response to irradiation in a p62-denpendent manner, and that inhibition of the HECTD3-p62 axis could be a potential therapeutic strategy for patients with TNBC in addition to radiotherapy.Funding: This work was supported by the National Key R&D Program of China (2020YFA0112300), National Science Foundation of China (U2102203 and 81830087 to CC and 82203411 to M. Huang); Expert Workstation of Ceshi Chen in Yunnan (Kunming) (YSZ-JFZZ-2020025); Yunnan Clinical Medical Center of Organ Transplantation (ZX2019-07-01); Yunnan Applied Basic Research Projects (202101AS070050 and 202301AY070001-264); Major projects for fundamental research of Yunnan province (202201BC070002); China Postdoctoral Science Foundation (2023M731448).Declaration of Interest: All of authors declare no conflicts of interest.Ethical Approval: All animal experiments were performed in accordance with the institutional ethical guidelines for animal care and approved by the Animal Resource Center at the Kunming Institute of Zoology.

It is well established that innervation is one of the updated hallmarks of cancer and that psychological stress promotes the initiation and progression of cancer. The breast tumor environment includes not only fibroblasts, adipocytes, endothelial cells, and lymphocytes but also neurons, which is increasingly discovered important in breast cancer progression. Peripheral nerves, especially sympathetic, parasympathetic, and sensory nerves, have been reported to play important but different roles in breast cancer. However, their roles in the breast cancer progression and treatment are still controversial. In addition, the brain is one of the favorite sites of breast cancer metastasis. In this review, we first summarize the innervation of breast cancer and its mechanism in regulating cancer growth and metastasis. Next, we summarize the neural-related molecular markers in breast cancer diagnosis and treatment. In addition, we review drugs and emerging technologies used to block the interactions between nerves and breast cancer. Finally, we discuss future research directions in this field. In conclusion, the further research in breast cancer and its interactions with innervated neurons or neurotransmitters is promising in the clinical management of breast cancer.