Guanosine diphosphate-mannose suppresses homologous recombination repair and potentiates antitumor immunity in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor prognosis. TNBCs with high homologous recombination deficiency (HRD) scores benefit from DNA-damaging agents, including platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors, whereas those with low HRD scores still lack therapeutic options. Therefore, we sought to exploit metabolic alterations to induce HRD and sensitize DNA-damaging agents in TNBCs with low HRD scores. We systematically analyzed TNBC metabolomics and identified a metabolite, guanosine diphosphate (GDP)-mannose (GDP-M), that impeded homologous recombination repair (HRR). Mechanistically, the low expression of the upstream enzyme GDP-mannose-pyrophosphorylase-A (GMPPA) led to the endogenous up-regulation of GDP-M in TNBC. The accumulation of GDP-M in tumor cells further reduced the interaction between breast cancer susceptibility gene 2 (BRCA2) and ubiquitin-specific peptidase 21 (USP21), which promoted the ubiquitin-mediated degradation of BRCA2 to inhibit HRR. Therapeutically, we illustrated that the supplementation of GDP-M sensitized DNA-damaging agents to impair tumor growth in both in vitro (cancer cell line and patient-derived organoid) and in vivo (xenograft in immunodeficient mouse) models. Moreover, the combination of GDP-M with DNA-damaging agents activated STING-dependent antitumor immunity in immunocompetent syngeneic mouse models. Therefore, GDP-M supplementation combined with PARP inhibition augmented the efficacy of anti-PD-1 antibodies. Together, these findings suggest that GDP-M is a crucial HRD-related metabolite and propose a promising therapeutic strategy for TNBCs with low HRD scores using the combination of GDP-M, PARP inhibitors, and anti-PD-1 immunotherapy.

Ferroptosis heterogeneity in triple-negative breast cancer reveals an innovative immunotherapy combination strategy.

Treatment of triple-negative breast cancer (TNBC) remains challenging. Deciphering the orchestration of metabolic pathways in regulating ferroptosis will provide new insights into TNBC therapeutic strategies. Here, we integrated the multiomics data of our large TNBC cohort (n = 465) to develop the ferroptosis atlas. We discovered that TNBCs had heterogeneous phenotypes in ferroptosis-related metabolites and metabolic pathways. The luminal androgen receptor (LAR) subtype of TNBC was characterized by the upregulation of oxidized phosphatidylethanolamines and glutathione metabolism (especially GPX4), which allowed the utilization of GPX4 inhibitors to induce ferroptosis. Furthermore, we verified that GPX4 inhibition not only induced tumor ferroptosis but also enhanced antitumor immunity. The combination of GPX4 inhibitors and anti-PD1 possessed greater therapeutic efficacy than monotherapy. Clinically, higher GPX4 expression correlated with lower cytolytic scores and worse prognosis in immunotherapy cohorts. Collectively, this study demonstrated the ferroptosis landscape of TNBC and revealed an innovative immunotherapy combination strategy for refractory LAR tumors.

Predicting Pathological Complete Response in Neoadjuvant Dual Blockade With Trastuzumab and Pertuzumab in HER2 Gene Amplified Breast Cancer.

Background: Dual-targeted therapy is the standard treatment for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and effective biomarkers to predict the response to neoadjuvant trastuzumab and pertuzumab treatment need further investigation. Here, we developed a predictive model to evaluate the dual-targeted neoadjuvant treatment efficacy in HER2 gene-amplified breast cancer. Method: This retrospective study included 159 HER2-amplified patients with locally advanced breast cancer who received neoadjuvant trastuzumab, pertuzumab, and chemotherapy. The correlation between clinicopathological factors and pathological complete response (pCR, in the breast and axilla) was evaluated. Patients were randomly assigned into the training set (n=110) and the testing set (n=49). We used an independent cohort (n=65) for external validation. We constructed our predictive nomogram model with the results of risk variables associated with pCR identified in the multivariate logistic analysis. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve, decision curve analysis, and calibration curves were employed to assess the nomogram's performance. Results: We revealed that the HER2/CEP17 ratio (p=0.001), CD8 levels (p=0.005), and histological grade (p=0.007) were independent indicators for pCR in dual-targeted neoadjuvant treatment after multivariate adjustment. The combined prediction efficacy of the three indicators was significantly higher than that of each single indicator alone. The AUCs were 0.819, 0.773, and 0.744 in the training, testing, and external validation sets, respectively. Conclusions: The HER2/CEP17 ratio, CD8 levels, and histological grade were significantly correlated with pCR in dual-targeted neoadjuvant treatment. The combined model using these three markers provided a better predictive value for pCR than the HER2/CEP17 ratio, CD8 levels, and the histological grade alone, which showed that an immunological effect partially mediates the predictive impact of neoadjuvant treatment.

Integrated analysis reveals the molecular features of fibrosis in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer. High fibrosis, marked by increased collagen fibers, is widespread in TNBC and correlated with tumor progression. However, the molecular features of fibrosis and why it results in a poor prognosis remain poorly understood. Based on multiomics datasets of TNBC, we evaluated the pathological fibrosis grade of 344 samples for further analysis. Genomic, transcriptomic, and immune changes were analyzed among different subgroups of fibrosis. High fibrosis was an independent adverse prognosis predictor and had interactions with low stromal tumor-infiltrating lymphocytes. Genomic analysis identified copy number gains of 6p22.2-6p22.1 (TRIM27) and 20q13.33 (CDH4) as genomic hallmarks of tumors with high fibrosis. Transcriptome analysis revealed the transforming growth factor-beta pathway and hypoxia pathway were key pro-oncogenic pathways in tumors with high fibrosis. Moreover, we systematically evaluate the relationship between fibrosis and different kinds of immune and stromal cells. Tumors with high fibrosis were characterized by an immunosuppressive tumor microenvironment with limited immune cell infiltration and increased fibroblasts. This study proposes new insight into the genomic and transcriptomic alterations potentially driving fibrosis. Moreover, fibrosis is related to an immunosuppressive tumor microenvironment that contributes to the poor prognosis.

Comprehensive metabolomics expands precision medicine for triple-negative breast cancer.

Metabolic reprogramming is a hallmark of cancer. However, systematic characterizations of metabolites in triple-negative breast cancer (TNBC) are still lacking. Our study profiled the polar metabolome and lipidome in 330 TNBC samples and 149 paired normal breast tissues to construct a large metabolomic atlas of TNBC. Combining with previously established transcriptomic and genomic data of the same cohort, we conducted a comprehensive analysis linking TNBC metabolome to genomics. Our study classified TNBCs into three distinct metabolomic subgroups: C1, characterized by the enrichment of ceramides and fatty acids; C2, featured with the upregulation of metabolites related to oxidation reaction and glycosyl transfer; and C3, having the lowest level of metabolic dysregulation. Based on this newly developed metabolomic dataset, we refined previous TNBC transcriptomic subtypes and identified some crucial subtype-specific metabolites as potential therapeutic targets. The transcriptomic luminal androgen receptor (LAR) subtype overlapped with metabolomic C1 subtype. Experiments on patient-derived organoid and xenograft models indicate that targeting sphingosine-1-phosphate (S1P), an intermediate of the ceramide pathway, is a promising therapy for LAR tumors. Moreover, the transcriptomic basal-like immune-suppressed (BLIS) subtype contained two prognostic metabolomic subgroups (C2 and C3), which could be distinguished through machine-learning methods. We show that N-acetyl-aspartyl-glutamate is a crucial tumor-promoting metabolite and potential therapeutic target for high-risk BLIS tumors. Together, our study reveals the clinical significance of TNBC metabolomics, which can not only optimize the transcriptomic subtyping system, but also suggest novel therapeutic targets. This metabolomic dataset can serve as a useful public resource to promote precision treatment of TNBC.

Molecular subtyping and genomic profiling expand precision medicine in refractory metastatic triple-negative breast cancer: the FUTURE trial.

Triple-negative breast cancer (TNBC) is a highly heterogeneous disease, and molecular subtyping may result in improved diagnostic precision and targeted therapies. Our previous study classified TNBCs into four subtypes with putative therapeutic targets. Here, we conducted the FUTURE trial (ClinicalTrials.gov identifier: NCT03805399), a phase Ib/II subtyping-based and genomic biomarker-guided umbrella trial, to evaluate the efficacy of these targets. Patients with refractory metastatic TNBC were enrolled and stratified by TNBC subtypes and genomic biomarkers, and assigned to one of these seven arms: (A) pyrotinib with capecitabine, (B) androgen receptor inhibitor with CDK4/6 inhibitor, (C) anti PD-1 with nab-paclitaxel, (D) PARP inhibitor included, (E) and (F) anti-VEGFR included, or (G) mTOR inhibitor with nab-paclitaxel. The primary end point was the objective response rate (ORR). We enrolled 69 refractory metastatic TNBC patients with a median of three previous lines of therapy (range, 1-8). Objective response was achieved in 20 (29.0%, 95% confidence interval (CI): 18.7%-41.2%) of the 69 intention-to-treat (ITT) patients. Our results showed that immunotherapy (arm C), in particular, achieved the highest ORR (52.6%, 95% CI: 28.9%-75.6%) in the ITT population. Arm E demonstrated favorable ORR (26.1%, 95% CI: 10.2%-48.4% in the ITT population) but with more high grade (≥ 3) adverse events. Somatic mutations of TOP2A and CD8 immunohistochemical score may have the potential to predict immunotherapy response in the immunomodulatory subtype of TNBC. In conclusion, the phase Ib/II FUTURE trial suggested a new concept for TNBC treatment, demonstrating the clinical benefit of subtyping-based targeted therapy for refractory metastatic TNBC.

Anti-cancer effects of CQBTO, a chloroquine, and benzo(e)triazine oxide conjugate.

AIM: Autophagy is a self-protective process, and it confers cancer cells resistance against radio-chemotherapeutics. To induce cancer cell death, a series of compounds of 3-((4-((7-chloroquinolin-4-yl)amino)butyl)amino)-7-substituted benzo[e][1,2,4]triazine 1-oxide or CQBTO containing two critical chemical groups were designed and synthesized. One compound, benzo[e][1,2,4]triazine 1-oxide, yielded free radicals to trigger autophagy, and the other one, chloroquine (CQ), was an inhibitor of autophagy. We hypothesized that the compounds could kill cancer cells effectively by inducing incomplete autophagy. METHODS: In vitro cultured non-small cell lung carcinoma cells and primary lung tumors in mice in vivo were used to test the lethal effects of CQBTO on cancer cells and toxicity to normal tissues. Cell viability was examined using the CCK8 assay. Genomic instability was determined with the cytochalasin B-blocked micronucleus assay. Cell cycle distribution was analyzed by propidium iodide staining and flow cytometry. Western blotting and immunofluorescence were used to detect the induction and localization of LC3, a biomarker for autophagy. RESULTS: Compared with CQ, three CQBTO compounds were lethal to lung cancer cells, and CQBTO-3 was the most effective. The LD50 for CQBTO-3 was 21 µΜ in A549 cells and 21.5 µΜ in Calu-1 cells, which was lower than that of CQBTO-2 or CQBTO-1. Induction of LC3 foci and an increase in the LC3II/LC3I ratio demonstrated the induction of autophagy by CQBTO-3 in A549 cells, whereas no obvious micronuclei or cell cycle arrest was observed. No detectable toxicity to normal mice was observed. CQBTO-3 improved the quality of mouse life, reduced the number and size of existing tumors, and suppressed tumor formation. CONCLUSION: CQBTO-3 is a potential chemical compound for lung cancer treatment.

Therapeutic ionizing radiation induced bone loss: a review of in vivo and in vitro findings.

Radiation therapy is one of the routine treatment modalities for cancer patients. Ionizing radiation (IR) can induce bone loss, and consequently increases the risk of fractures with delayed and nonunion of the bone in the cancer patients who receive radiotherapy. The orchestrated bone remodeling can be disrupted due to the affected behaviors of bone cells, including bone mesenchymal stem cells (BMSCs), osteoblasts and osteoclasts. BMSCs and osteoblasts are relatively radioresistant compared with osteoclasts and its progenitors. Owing to different radiosensitivities of bone cells, unbalanced bone remodeling caused by IR is closely associated with the dose absorbed. For doses less than 2 Gy, osteoclastogenesis and adipogenesis by BMSCs are enhanced, while there are limited effects on osteoblasts. High doses (>10 Gy) induce disrupted architecture of bone, which is usually related to decreased osteogenic potential. In this review, studies elucidating the biological effects of IR on bone cells (BMSCs, osteoblasts and osteoclasts) are summarized. Several potential preventions and therapies are also proposed.