NK/T-cell lymphoma (NKTL) is a highly aggressive non-Hodgkin's lymphoma characterized by extranodal involvement. Programmed cell death protein 1 (PD-1) monoclonal antibody (anti-PD1) treatment is ineffective in some patients, leading to recurrence or metastasis. The resistance to anti-PD1 treatment remains a major challenge in clinics. To identify the core molecules responsible for anti-PD1 treatment resistance and explore the possible molecular mechanisms behind it, simulating the human immune microenvironment during PD-1 treatment is essential. In this study, human peripheral blood mononuclear cells (PBMCs) were transplanted into immunodeficient mice to reconstitute human immunity in mice. The results showed that after immune reconstitution, human immune cells, especially T cells, remain at a high level (≥90%) for at least 4 weeks, indicating that human PBMCs were successfully reconstituted in immunodeficient mice. Two weeks after PBMCs implantation, human NKTL cells (SNK1, KHYG1 and YT) were subcutaneously inoculated into the right lower abdomen of mice. Then, high-dose anti-PD1 treatment was initiated (about 50 mm3, Sintilimab, twice a week, 10 mg/kg each time). The tumor from the mice was removed (≤than 1500 mm3) to prepare a single-cell suspension and re-implanted into the mice. The above process was repeated 5 times (280 days in total). The tumor growth inhibition‌ (TGI) values of NKTL cells before and after induction (71.89% and 1.08% for KHYG1 cells, 54.37% and 3.79% for SNK1 cells, 51.17% and 6.34% for YT cells, respectively) confirmed the successful construction of anti-hPD1-induced resistance NKTL cells (SNK1-Re, KHYG1-Re and YT-Re). Subsequently, we performed transcriptomic, proteomic, and metabolomic analyses on the above resistant and sensitive cell lines. Through multiple functional experiments and clinical sample verification, we confirmed that the transcriptional repressor Zinc finger BED-type containing 6 (ZBED6) was a key biomarker for anti-PD1 treatment resistance in NKTL. Downregulated ZBED6 creates a thymidine-deficient environment by E2F transcription factor 1 (E2F1)-ribonucleoside-diphosphate reductase subunit M2 (RRM2)/dihydropyrimidine dehydrogenase (DPYD), in which drug-resistant tumor cells scavenge thymidine (TdR) from the tumor microenvironment via solute carrier family 29 member 1 (SLC29A1) to increase nucleotide synthesis, thereby establishing an immunosuppressive niche, resulting in the ineffectiveness of anti-PD1 immunotherapy.

Triple-negative breast cancer (TNBC) is characterized by aggressive metastatic behavior and limited therapeutic options. Although metabolic reprogramming is increasingly recognized as a hallmark of TNBC, the mechanisms by which specific metabolic enzymes and intermediates drive metastasis remain poorly defined. We performed untargeted metabolomic profiling on TNBC tumors and matched normal tissues to identify dysregulated metabolic pathways. Functional assays, chemoproteomic succination profiling, molecular interaction analyses, and in vivo cancer metastasis models were used to define the mechanistic and biological consequences of altered metabolism. In vitro experiments validated the effects of N-acetylcysteine (NAC) in TNBC cell lines. Metabolomic analyses revealed aberrant activation of the alanine–aspartate–glutamate axis and upregulation of adenylosuccinate lyase (ADSL) in TNBC. ADSL promoted tumor cell proliferation and metastasis by generating fumarate, which accumulated primarily through covalent protein succination. Chemoproteomic profiling identified the cell polarity regulator SCRIB as a critical fumarate target. Fumarate-mediated succination of SCRIB impaired its membrane localization, promoted epithelial–mesenchymal transition, and facilitated aberrant interaction with the mTORC2 component RICTOR, leading to activation of AKT/mTOR signaling. Genetic disruption of SCRIB succination abrogated these effects. Importantly, pharmacological perturbation of fumarate using NAC reduced SCRIB succination and attenuated the malignant phenotypes of TNBC cells in vitro. These findings identify an ADSL-fumarate-SCRIB signaling axis that links metabolic reprogramming to the loss of cell polarity and activation of pro-metastatic signaling in TNBC. Targeting fumarate-mediated protein succination represents a previously unrecognized and experimental vulnerability in TNBC.

Fasting-mimicking diets (FMD) have been reported to increase the anti-tumor efficacy in preclinical studies in various cancers. FMD can impact the tumor microenvironment (TME), and elucidating the mechanisms and cells mediating the effects of FMD may uncover combination treatment strategies. Here, we performed single-cell transcriptomic sequencing to characterize the TME changes induced by FMD intervention in a mouse model of spontaneous breast cancer. The sequencing data indicated that FMD suppressed tumor cell stemness, promoted apoptosis, and increased the infiltration of innate and adaptive immune cells, especially natural killer (NK) cells and effector CD8+T cells. Importantly, FMD induced phenotypic reprogramming of cancer-associated fibroblasts (CAFs), leading to a decrease in the immunosuppressive inflammatory CAF (iCAF) subset. Mechanistically, FMD decreased platelet-derived growth factor C (PDGFC) secretion in tumor cells by reducing glucose and inhibiting glycolysis to reprogram CAFs. PDGFC increased activation of the JAK/STAT3 pathway, which induced iCAF differentiation. Combining FMD with PDGFR inhibitors increased the efficacy of anti-PD-L1 immunotherapy in vivo. Overall, this study reveals a mechanism of metabolic-immune rewiring through which FMD suppresses tumor progression, providing preliminary evidence for the potential of combination FMD-based strategies in breast cancer treatment.

Cancer-associated fibroblasts (CAFs) constitute a critical component of the tumor microenvironment (TME). CAFs can be reprogrammed by cancer cells, leading to the production of extracellular vesicles (EVs). These EVs serve as carriers for bioactive substances, including proteins, nucleic acids, and metabolic products, thereby facilitating tumor progression. CAF-derived EVs exert substantial influence on tumor cell proliferation, invasion, and metastasis, the immunological environment, and the processes of lymphangiogenesis and angiogenesis. Despite their potential as non-invasive biomarkers and therapeutic delivery vehicles, the clinical application of CAF-derived EVs is currently limited by challenges in purification and precise targeting. This review delineates the diverse roles of CAF-derived EVs in tumor growth, metastasis, and immune evasion within the TME.

1117 Background: Trastuzumab deruxtecan (T-DXd) has been approved for patients (pts) with HER2-ultralow metastatic breast cancer (MBC). HER2 discordance commonly occurs between primary and metastatic lesions within the same patient; however, its incidence remains unknown in the HER2-ultralow era. Additionally, there is still controversy about which specimen to use to determine HER2-ultralow status and optimal threshold to guide T-DXd therapy. Methods: This national, multicenter cohort study included MBC pts treated with T-DXd (5.4 mg/kg) with HER2 status available for both primary tumors and matched metastases between January 2020 and October 2024 (NCT06551220). HER2 status was determined according to the DB-06 protocol. Pts were divided into three cohorts based on HER2 discordance patterns: cohort 1 (HER2-positive/low/ultralow in both primary and metastases), cohort 2 (HER2-positive/low/ultralow in primary and HER2-null in metastases), and cohort 3 (HER2-null in primary and HER2-positive/low/ultralow in metastases). Endpoints included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate, and clinical benefit rate. Results: From 24 centers nationwide, 3546 pts met the criteria and were included. The incidence of HER2 discordance between primary and matched metastases has changed across eras of HER2-positivity definitions: HER2-positive era (9.8%, K = 0.78), HER2-low era (25.0%, K = 0.39), and HER2-ultralow era (20.2%, K = 0.16). Among T-DXd-treated pts (n = 1052), a higher response rate was observed in cohort 1 (ORR = 55.7%) and cohort 3 (ORR = 53.1%) compared to cohort 2 (ORR = 13.0%). ORR is positively correlated with HER2 expression if metastatic lesions are used as the examined tissue (positive 62.9%, low 49.8%, ultralow 47.0%, null 13.0%). However, the correlation between ORR and HER2 expression is not significant when primary lesions were examined (positive 57.8%, low 41.5%, ultralow 54.4%, null 53.1%). Additionally, cohort 1 (mPFS = 11.6 mo, mOS = 30.7 mo) and cohort 3 (mPFS = 10.9 mo, mOS = 18.4 mo) exhibited significantly superior PFS and OS compared to cohort 2 (mPFS = 6.1 mo, mOS = 12.3 mo). Faint incomplete membrane staining percentage ≥5% in metastatic lesion was the best threshold to distinguish PFS (HR = 0.54, P = 0.02; mPFS, 11.4 vs 8.6 mo) and ORR (OR = 4.00, P = 0.01; 60% vs 27%) among HER2-ultralow MBC treated with T-DXd. Conclusions: A high HER2-ultralow discordance rate was observed between primary tumors and matched metastases. HER2 status in metastatic specimens more accurately predicts T-DXd efficacy compared to primary specimens. A staining threshold of ≥5% tumor cells in metastatic lesions may optimize T-DXd treatment in HER2-ultralow MBC. Therefore, re-evaluating HER2 status in metastatic lesions is recommended for T-DXd treatment decision.

Background: Limited data are available on estradiol (E2) levels during fulvestrant treatment in women with hormone receptor-positive breast cancer. Methods: We measured plasma E2 levels in women receiving fulvestrant using liquid chromatography–tandem mass spectrometry. Patient characteristics and treatment efficacy were assessed in relation to E2 levels. A cutoff of 2.72 pg/mL was used because it defines E2 suppression and postmenopausal status. Results: A total of 69 women were enrolled, with a median age of 48 years. The median duration of fulvestrant treatment was 11.6 months. The median E2 level across the cohort was 3.60 pg/mL, with considerable interindividual variability (range: 1.11-526.13 pg/mL), and 49 women (71.0%) had E2 levels above 2.72 pg/mL. Eleven women (15.9%) had premenopausal E2 levels (>10 pg/mL). During a median follow-up period of 8.4 months, there was no statistically significant difference in progression-free survival (PFS) between women with E2 levels >2.72 pg/mL and those with E2 levels ≤2.72 pg/mL (P = .391). However, among women who benefited from first- or second-line fulvestrant therapy (PFS > 6 months), those with E2 levels >2.72 pg/mL exhibited significantly poorer PFS compared to those with E2 levels ≤2.72 pg/mL (P = .043). Conclusions: These findings support the need for E2 monitoring in women receiving fulvestrant therapy to better assess E2 status and its association with treatment efficacy.

Supplementary Table from Effects of Infection-Induced Fever and the Interaction with IL6 rs1800796 Polymorphism on the Prognosis of Breast Cancer

Melanoma is a type of skin cancer originating from melanocytes with a high risk of gastrointestinal tract metastasis. The abnormal expression of cyclin-dependent kinase-like 3 (CDKL3) is involved in several tumor progression. However, the role of CDKL3 in malignant melanoma has never been reported and remains unknown. In this study, the expression of CDKL3 was revealed using clinical human malignant melanoma tissues and normal skin tissues. The effects of CDKL3 on malignant melanoma cell phenotypes was evaluated in vitro and in vivo via establishing CDKL3 deficiency cell models. Our results indicated that CDKL3 was highly expressed in malignant melanoma tissues, especially in advanced malignant melanoma tissues, in comparison with normal skin tissues. Moreover, CDKL3 knockdown significantly suppressed the proliferation, migration and invasion of malignant melanoma cells, and induced cell apoptosis. The indispensable role of CDKL3 on tumorigenesis was confirmed through in vivo experiments. Finally, we showed that CDKL3 promoted malignant melanoma progression via targeting autophagy related 5 (ATG5). CDKL3 induced melanoma cell autophagy through an ATG5-dependent manner. In conclusion, these results showed the promoting role of CDKL3 in proliferation and migration of malignant melanoma cells. The CDKL3 may be a novel biomarker for malignant melanoma progression and the potential therapeutic target for patients with malignant melanoma.

Xie, Jindong; Deng, Xinpei; Yang, Anli; Zheng, Shaoquan; Tang, Yuhui; Xie, Yi; Zhang, Junsheng; Tang, Hailin; Chen, Wenkuan; Zou, Yutian PhD, MD; Xie, Xiaoming Author Information

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, characterized by a high propensity for metastasis, poor prognosis, and limited treatment options. Research has demonstrated a substantial correlation between the expression of protein arginine N-methyltransferase 1 (PRMT1) and enhanced proliferation, metastasis, and poor outcomes in TNBC. However, the specific role of PRMT1 in lung metastasis and chemoresistance remains unclear. Single-cell RNA sequencing coupled with bioinformatics analysis was employed to identify pertinent genes within metastatic TNBC samples. Functional assays, including cell cycle, apoptosis, wound healing, Transwell migration, colony formation, and Cell Counting Kit-8 Assay (CCK-8), were conducted to evaluate the role of PRMT1. The interaction between PRMT1 and PARP1 was validated by mass spectrometry (MS) and immunoprecipitation. Downstream signaling pathways were explored, with a focus on P65 activation. Enzyme-linked immunosorbent assay was used to quantify the effect of PRMT1 on interleukin-1β secretion. Our study identified a significant association between elevated PRMT1 expression and both lung metastasis and chemoresistance in TNBC. PRMT1 boosts TNBC cell growth, invasion, and lung metastasis. Additionally, high PRMT1 expression contributed to increased resistance to docetaxel in TNBC. Mechanistically, PRMT1 methylates PARP1. On the one hand, this methylation promotes the DNA damage repair ability of PAPA1. On the other hand, it in turn modulates the NF-κB signaling pathway. This modulation enhances the stemness of tumor cells and induces immune suppression within the tumor microenvironment, thereby exacerbating chemoresistance in TNBC. PRMT1 drives lung metastasis and chemoresistance in TNBC through PARP1 methylation and P65 activation. These findings position PRMT1 as a promising biomarker and therapeutic target to overcome resistance and limit metastatic progression in TNBC.

PURPOSE:The limited understanding of long-term estradiol (E2) suppression poses challenges to the effectiveness of adjuvant therapy with aromatase inhibitors (AI), necessitating comprehensive serum E2 monitoring to address this issue. Therefore, our objective was to investigate serum E2 levels in women undergoing adjuvant AI treatment and evaluate the significance of such monitoring. PATIENTS AND METHODS:In this prospective cohort study, we recruited women who had received adjuvant AI treatment, including those who underwent ovarian function suppression (OFS). Serum E2 levels were measured using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The primary endpoint was the proportion of women with E2 levels exceeding 2.72 pg/mL, indicating inadequate suppression achieved with AI therapy. RESULTS:A total of 706 patients were enrolled, including 482 women with OFS in combination with AI. Among them, 116 women (16.4 %) exhibited E2 levels exceeding 2.72 pg/mL. The majority of serum E2 elevations (77.6 %) occurred within the first two years of initiating endocrine therapy. Younger age, no prior chemotherapy, shorter duration of the current treatment regimen, and lower follicle stimulating hormone (FSH) levels were associated with inadequate E2 suppression. Serum E2 concentrations demonstrated dynamic variations and occasional rebound following adjuvant AI therapy. CONCLUSIONS:Despite receiving adjuvant AI treatment for nearly two years, a certain proportion of patients failed to achieve the adequate threshold of E2 suppression. Our findings emphasize the significance of monitoring serum E2 levels during adjuvant AI therapy, particularly within the first two years. Further research is imperative to facilitate a more comprehensive comprehension of E2 monitoring.

Aims: With the wide application of trastuzumab deruxtecan (T-DXd), the survival of HER2-low breast cancer patients is dramatically improved. However, resistance to T-DXd still exists in a subset of patients, and the molecular mechanism remains unclear. Methods: An in vivo shRNA lentiviral library functional screening was performed to identify potential circular RNA (crRNA) that mediates T-DXd resistance. RNA pull-down, mass spectrometry, RNA immunoprecipitation, and co-immunoprecipitation assays were conducted to investigate the molecular mechanism. Ferroptosis was detected using C11-BODIPY, Liperfluo, FerroOrange staining, glutathione quantification, malondialdehyde quantification, and transmission electron microscopy. Molecular docking, virtual screening, and patient-derived xenograft (PDX) models were used to validate therapeutic agents. Results: VDAC3-derived crRNA (crVDAC3) ranked first in functional shRNA library screening. Knockdown of crVDAC3 increased the sensitivity of HER2-low breast cancer cells to T-DXd treatment. Further mechanistic research revealed that crVDAC3 specifically binds to HSPB1 protein and inhibits its ubiquitination degradation, leading to intracellular accumulation and increased levels of HSPB1 protein. Notably, suppression of crVDAC3 dramatically increases excessive ROS levels and labile iron pool accumulation. Inhibition of crVDAC3 induces ferroptosis in breast cancer cells by reducing HSPB1 expression, thereby mediating T-DXd resistance. Through virtual screening and experimental validation, we identified that paritaprevir could effectively bind to crVDAC3 and prevent its interaction with HSPB1 protein, thereby increasing ubiquitination degradation of HSPB1 protein to overcome T-DXd resistance. Finally, we validated the enhanced therapeutic efficacy of T-DXd by paritaprevir in a HER2-low PDX model. Conclusion: This finding reveals the molecular mechanisms underlying T-DXd resistance in HER2-low breast cancer. Our study provides a new strategy to overcome T-DXd resistance by inhibiting the interaction between crVDAC3 and HSPB1 protein.

Gut microbiota is essential for maintaining local and systemic immune homeostasis in the presence of bacterial challenges. It has been demonstrated that microbiota play contrasting roles in cancer development as well as anticancer immunity. Cancer immunotherapy, a novel anticancer therapy that relies on the stimulation of host immunity, has suffered from a low responding rate and incidence of severe immune-related adverse events (irAEs). Previous studies have demonstrated that the diversity and composition of gut microbiota were associated with the heterogeneity of therapeutic effects. Therefore, alteration in microbiota taxa can lead to improved clinical outcomes in immunotherapy. In this review, we determine whether microbiota composition or microbiota-derived metabolites are linked to responses to immunotherapy and irAEs. Moreover, we discuss various approaches to improve immunotherapy efficacy or reduce toxicities by modulating microbiota composition.

Disruption of disulfide homeostasis during biological processes can have fatal consequences. Excess disulfides induce cell death in a novel manner, termed as "disulfidptosis." However, the specific mechanism of disulfidptosis has not yet been elucidated. To determine the cancer types sensitive to disulfidptosis and outline the corresponding treatment strategies, we firstly investigated the crucial functions of disulfidptosis regulators pan-cancer at multi-omics levels. We found that different tumor types expressed dysregulated levels of disulfidptosis regulators, most of which had an impact on tumor prognosis. Moreover, we calculated the disulfidptosis activity score in tumors and validated it using multiple independent datasets. Additionally, we found that disulfidptosis activity was correlated with classic biological processes and pathways in various cancers. Disulfidptosis activity was also associated with tumor immune characteristics and could predict immunotherapy outcomes. Notably, the disulfidptosis regulator, glycogen synthase 1 (GYS1), was identified as a promising target for triple-negative breast cancer and validated via in vitro and in vivo experiments. In conclusion, our study elucidated the complex molecular phenotypes and clinicopathological correlations of disulfidptosis regulators in tumors, laying a solid foundation for the development of disulfidptosis-targeting strategies for cancer treatment.

Aggressive triple-negative breast cancer (TNBC) still lacks approved targeted therapies, requiring more exploration of its underlying mechanisms. Previous studies have suggested a potential role of SAT1 (Spermidine/Spermine N1-acetyltransferase 1) in cancer, which needs to be further elucidated in breast cancer. In this study, highly expressed SAT1 in TNBC signified worse patient prognoses. And SAT1 knockdown effectively inhibited the proliferation and migration abilities of TNBC cells in vitro and in vivo. In terms of mechanism, the transcription factor JUN enhanced SAT1 transcriptional activity by binding to its promoter region. Then, SAT1 protein in the cytoplasm engaged in directly binding with YBX1 for sustaining YBX1 protein stability via deubiquitylation mediated by the E3 ligase HERC5. Further, SAT1 was found to suppress autophagy remarkably via stabilization of mTOR mRNA with the accumulation of YBX1-mediated methyl-5-cytosine (m5C) modification. These findings proved that SAT1 drives TNBC progression through the SAT1/YBX1/mTOR axis, which may provide a potential candidate for targeted therapy in advanced TNBC.

Among patients with triple-negative breast cancer (TNBC), distant metastasis is the leading cause of death. Our previous studies have shown that TNBC progression is greatly facilitated by circKIF4A, but uncertainty remains regarding its role in TNBC brain metastasis and the molecular mechanism. In this study, we found notable upregulation of circKIF4A in TNBC cell lines and brain metastases. Inhibition of circKIF4A impaired the ability of TNBC to proliferate, migrate, and cause brain metastasis. Luciferase reporter assays confirmed that circKIF4A competed for binding to miR-637 with STAT3 3' UTR. Western blot analysis revealed that inhibition of circKIF4A decreased STAT3 and p62 expression, while increased the LC3B-II/LC3B-I ratio and the expression of Beclin, indicating that downregulation of circKIF4A induced autophagy by competing with STAT3 for binding to miR-637. By employing a competitive endogenous RNA (ceRNA) mechanism, the circKIF4A-miR-637-STAT3 axis coordinates brain metastasis in TNBC. circKIF4A can therefore be used as a prognostic biomarker for brain metastasis in TNBC and as a therapeutic target.

AimsThis study aims to explore the function and mechanism of G Protein-coupled receptor class C group 5 member A (GPRC5A) in docetaxel-resistance and liver metastasis of breast cancer.MethodsSingle-cell RNA transcriptomic analysis and bioinformatic analysis are used to screen relevant genes in breast cancer metastatic hepatic specimens. MeRIP, dual-luciferase analysis and bioinformation were used to detect m6A modulation. Mass spectrometry (MS), co-inmunoprecipitation (co-IP) and immunofluorescence colocalization were executed to explore the mechanism of GPRC5A in breast cancer cells.ResultGPRC5A was upregulated in triple-negative breast cancer (TNBC) and was associated with a poor prognosis. In vitro and in vivo experiments demonstrated that knockdown of GPRC5A alleviated metastasis and resistance to docetaxel in TNBC. Overexpression of GPRC5A had the opposite effects. The m6A methylation of GPRC5A mRNA was modulated by METTL3 and YTHDF1, which facilitates its translation. GPRC5A inhibited the ubiquitination-dependent degradation of LAMTOR1, resulting in the recruitment of mTORC1 to lysosomes and activating the mTORC1/p70s6k signaling pathway.ConclusionMETTL3/YTHDF1 axis up-regulates GPRC5A expression by m6A methylation. GPRC5A activates mTORC1/p70s6k signaling pathway by recruiting mTORC1 to lysosomes, consequently promotes docetaxel-resistance and liver metastasis.

Univariate and multivariable Cox regression analysis of DFS (Cox proportional hazards regression model)