Explore the vast range of titles available.

Background Metabolic plasticity mediates breast cancer survival, growth, and immune evasion during metastasis. However, how tumor cell metabolism is influenced by and feeds back to regulate breast cancer progression are not fully understood. We identify hypoxia-mediated suppression of pyruvate carboxylase (PC), and subsequent induction of lactate production, as a metabolic regulator of immunosuppression. Methods We used qPCR, immunoblot, and reporter assays to characterize repression of PC in hypoxic primary tumors. Steady state metabolomics were used to identify changes in metabolite pools upon PC depletion. In vivo tumor growth and metastasis assays were used to evaluate the impact of PC manipulation and pharmacologic inhibition of lactate transporters. Immunohistochemistry, flow cytometry, and global gene expression analyzes of tumor tissue were employed to characterize the impact of PC depletion on tumor immunity. Results PC is essential for metastatic colonization of the lungs. In contrast, depletion of PC in tumor cells promotes primary tumor growth. This effect was only observed in immune competent animals, supporting the hypothesis that repression of PC can suppress anti-tumor immunity. Exploring key differences between the pulmonary and mammary environments, we demonstrate that hypoxia potently downregulated PC. In the absence of PC, tumor cells produce more lactate and undergo less oxidative phosphorylation. Inhibition of lactate metabolism was sufficient to restore T cell populations to PC-depleted mammary tumors. Conclusions We present a dimorphic role for PC in primary mammary tumors vs. pulmonary metastases. These findings highlight a key contextual role for PC-directed lactate production as a metabolic nexus connecting hypoxia and antitumor immunity. Graphical abstract

Introduction Triple-negative breast cancer (TNBC), which tends to be more advanced when diagnosed and more aggressive than other breast cancer subtypes, is accelerated by obesity. Hypertrophic adipocytes and cancer cells exhibit increased oxidative stress and altered redox homeostasis, influencing therapeutic outcomes. Enzymes implicated in both redox regulation and TNBC include glutathione peroxidase 4 (GPX4; reduces lipid peroxides) and pyruvate carboxylase (PC; essential in oxidative stress protection). Using preclinical models, we characterized interactions between GPX4, PC, and oxidative stress in TNBC cells, and established effects of GPX4 suppression on TNBC progression. In TNBC cells, PC knockdown increased GPX4 expression, while GPX4 knockdown increased PC expression. GPX4 inhibition by erastin or RSL3 enhanced TNBC cell death in vitro, and antioxidants mitigated the cytotoxicity. In obese mice, GPX4 knockdown, versus scramble control: (i) reduced tumor burden following orthotopic transplantation of TNBC cells; and (ii) reduced lung metastasis following tail vein injection of TNBC cells in combination with chemotherapy (carboplatin) but not immunotherapy (anti-CTLA4 plus anti-PD1). We conclude that GPX4 and PC expression are inversely related in TNBC cells, and GPX4 and obesity interact to impact TNBC progression and treatment responses. Moreover, GPX4-mediated redox defense, alone or in combination with chemotherapy, is a targetable vulnerability for treating TNBC, including obesity-related TNBC. Implication GPX4 suppression, alone or with current TNBC therapies, impacts outcomes in preclinical TNBC models with or without obesity and offers a new, plausible mechanistic target for TNBC treatment.

Triple-negative breast cancer (TNBC) lacks targeted therapies, leaving cytotoxic chemotherapy as the current standard treatment. However, chemotherapy resistance remains a major clinical challenge. Increased insulin-like growth factor 1 signaling can potently blunt chemotherapy response, and lysosomal processes including the nutrient scavenging pathway autophagy can enable cancer cells to evade chemotherapy-mediated cell death. Thus, we tested whether inhibition of insulin receptor/insulin-like growth factor 1 receptor with the drug BMS-754807 and/or lysosomal disruption with hydroxychloroquine (HCQ) could sensitize TNBC cells to the chemotherapy drug carboplatin. Using in vitro studies in multiple TNBC cell lines, in concert with in vivo studies employing a murine syngeneic orthotopic transplant model of TNBC, we show that BMS-754807 and HCQ each sensitized TNBC cells and tumors to carboplatin and reveal that exogenous metabolic modulators may work synergistically with carboplatin as indicated by Bliss analysis. Additionally, we demonstrate the lack of overt in vivo toxicity with our combination regimens and, therefore, propose that metabolic targeting of TNBC may be a safe and effective strategy to increase sensitivity to chemotherapy. Thus, we conclude that the use of exogenous metabolic modulators, such as BMS-754807 or HCQ, in combination with chemotherapy warrants additional study as a strategy to improve therapeutic responses in women with TNBC.

Calorie restriction (CR) inhibits triple-negative breast cancer (TNBC) progression in several preclinical models in association with decreased insulin-like growth factor 1 (IGF1) signaling. To investigate the impact of CR on microRNAs (miRs) that target the IGF1/IGF1R pathway, we used the spontaneous murine model of TNBC, C3(1)/SV40 T-antigen (C3-TAg). In C3-TAg mice, CR reduced body weight, IGF1 levels, and TNBC progression. We evaluated the tumoral expression of 10 miRs. CR increased the expression of miR-199a-3p, miR-199a-5p, miR-486, and miR-15b. However, only miR-15b expression correlated with tumorigenicity in the M28, M6, and M6C C3-TAg cell lines of TNBC progression. Overexpressing miR-15b reduced the proliferation of mouse (M6) and human (MDA-MB-231) cell lines. Serum restriction alone or in combination with low levels of recombinant IGF1 significantly upregulated miR-15b expression and reduced Igf1r in M6 cells. These effects were reversed by the pharmacological inhibition of IGFR with BMS754807. In silico analysis using miR web tools predicted that miR-15b targets genes associated with IGF1/mTOR pathways and the cell cycle. Our findings suggest that CR in association with reduced IGF1 levels could upregulate miR-15b to downregulate Igf1r and contribute to the anticancer effects of CR. Thus, miR-15b may be a therapeutic target for mimicking the beneficial effects of CR against TNBC.

We have reported that chimeric antigen receptor (CAR) T cells targeting B7-H3 (B7-H3.CAR) are effective in a preclinical model of triple negative breast cancer (TNBC), and have initiated a Phase I study to assess safety and efficacy. However, heterogeneous antigen expression and immunosuppressive tumor microenvironments (TME) remain roadblocks for effective CAR-T cell therapy. In particular, obesity represents a negative prognostic factor in TNBC partly due to chronic inflammation and impaired adaptive immune responses. Hence, we sought to determine if obesity can affect the antitumor activity of B7-H3.CAR-T cells. We used qPCR and western blotting to determine if cytokines associated with obesity affect B7-H3 expression in TNBC cell lines. Furthermore, we used shRNA to suppress B7-H3 expression in a syngeneic orthotopic E0771 tumor model and measured tumor growth in control and diet-induced obese (DIO) mice. Finally, we evaluated the antitumor effects of B7-H3.CAR-T cells in both control and DIO mice orthotopically engrafted with the E0771 tumor cell line. Immune profiling was conducted using flow cytometry. Obesity-related inflammatory cytokines promote B7-H3 expression in human and murine TNBC cells in vitro and B7-H3 expression correlates with tumor aggressiveness in vivo. CAR-T cells obtained from control or DIO mice were equally cytotoxic in vitro but activated T cells and B7-H3.CAR-T cells obtained from DIO mice show transcriptomic changes (enriched ) and impaired glycolytic capacity, respectively. Finally, we demonstrated that obesity impairs CAR-T cell antitumor effects and durability of response in vivo with a near complete loss of memory formation. Here we identified a correlation between B7-H3 expression, obesity, and rate of tumor growth in TNBC. Furthermore, we showed that obesity constrains both the ability of B7-H3.CAR-T cells to control tumor growth and to elicit durable immunological memory. Taken together, these data identify obesity as an underappreciated and potent modulator of CAR-T cell functionality. B7-H3 protein is upregulated in many human malignancies including TNBC and is often associated with worsened outcomes. B7-H3.CAR-T cells show promise in preclinical models of TNBC and entered clinical translation. This study identifies a previously unknown correlation between obesity, B7-H3 expression, and rate of tumor growth in TNBC. Furthermore, our preclinical model of B7-H3.CAR-T cell therapy demonstrates that obesity negatively affects the antitumor activity of B7-H3.CAR-T cells in TNBC. This study highlights obesity as an understudied and critically important covariate for adoptive T-cell therapy and demonstrates important links between systemic metabolism and antigen expression. This work paves the way for future mechanistic and translational research into how obesity impacts CAR-T cell functionality.

We report for the first time an anticancer benefit of tirzepatide-a dual glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide receptor agonist-in a model of obesity and breast cancer in female mice. Long-term tirzepatide treatment induced weight loss, mitigated obesity-driven changes in circulating metabolic hormone levels, and suppressed orthotopic E0771 mammary tumor growth. Relative to tirzepatide, chronic calorie restriction, an established anticancer intervention in preclinical models, promoted even greater weight loss, systemic hormonal regulation, and tumor suppression. We conclude that tirzepatide represents a promising pharmacologic approach for mitigating the procancer effects of obesity. Moreover, strategies promoting greater weight loss than achieved with tirzepatide alone may augment the anticancer benefits of tirzepatide.

Triple-negative breast cancers (TNBCs) are an aggressive breast cancer subtype with systemic chemotherapy as the only current treatment option. Metabolic reprogramming is key to tumor resistance to stressors including therapy. We hypothesized that targeting nutrient-sensing pathways through IGF-1R/IR and mTORC1 inhibition would increase efficacy of the platinum-based agent carboplatin and that autophagy underpins cell survival. We investigated combinatorial drug treatment effects on cytotoxicity, target inhibition, and mitochondrial function in MDA-MD-231 cells. IGF-1R/IR and mTORC1 inhibition with BMS-754807 and everolimus, respectively, increased the cytotoxicity of carboplatin while BMS-754807 interacted with the autophagy inhibitor chloroquine increasing growth inhibition. This work indicates that IGF-1R/IR and/or mTORC1 suppression is potentially synergistic with carboplatin in TNBC cells and suggests IGF-1R/IR inhibition can collaborate with autophagy inhibition to suppress TNBC growth. We conclude that inhibiting nutrient-sensing metabolic pathways with chemotherapy and/or autophagy inhibition warrants additional study as a strategy to improve response in women with TNBC.

Obesity, an established risk and progression factor for at least 13 cancer types, is highly prevalent globally, and effective strategies to mitigate the burden of obesity-related cancer are urgently needed. We investigated whether tirzepatide, a widely used incretin-mimetic drug that induces substantial weight loss, offers anticancer benefits. Across 3 tumor models, we demonstrate that chronic tirzepatide treatment reverses diet-induced increases in body weight and fat mass, systemic metabolic perturbations, and tumor growth. We also showed that the anticancer activity of tirzepatide does not involve direct effects on the neoplastic cells used, which lack incretin receptor expression. The anticancer actions of tirzepatide require the reversal of both the metabolic dysregulation and hyporesponsiveness of CD8+ tumor infiltrating lymphocytes evident in obesity. Our findings establish tirzepatide as a promising compound for intercepting obesity-related cancers.

Mammalian genomes comprise largely intergenic noncoding DNA with numerous cis -regulatory elements. Whether and how the size of intergenic DNA affects gene expression in a tissue-specific manner remain unknown. Here we show that genes with extended intergenic regions are preferentially expressed in neural tissues but repressed in other tissues in mice and humans. Extended intergenic regions contain twice as many active enhancers in neural tissues compared to other tissues. Neural genes with extended intergenic regions are globally co-expressed with neighboring neural genes controlled by distinct enhancers in the shared intergenic regions. Moreover, generic neural genes expressed in multiple tissues have significantly longer intergenic regions than neural genes expressed in fewer tissues. The intergenic regions of the generic neural genes have many tissue-specific active enhancers containing distinct transcription factor binding sites specific to each neural tissue. We also show that genes with extended intergenic regions are enriched for neural genes only in vertebrates. The expansion of intergenic regions may reflect the regulatory complexity of tissue-type-specific gene expression in the nervous system. A large part of noncoding DNA is intergenic regions, yet how the size of intergenic regions affects gene expression in a tissue-specific manner is unclear. Here the authors present long intergenic DNA length-dependent neural gene expression, reflecting the complexity in the mammalian nervous system.

Achieving universal health coverage (UHC) involves all people receiving the health services they need, of high quality, without experiencing financial hardship. Making progress towards UHC is a policy priority for both countries and global institutions, as highlighted by the agenda of the UN Sustainable Development Goals (SDGs) and WHO's Thirteenth General Programme of Work (GPW13). Measuring effective coverage at the health-system level is important for understanding whether health services are aligned with countries' health profiles and are of sufficient quality to produce health gains for populations of all ages. Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we assessed UHC effective coverage for 204 countries and territories from 1990 to 2019. Drawing from a measurement framework developed through WHO's GPW13 consultation, we mapped 23 effective coverage indicators to a matrix representing health service types (eg, promotion, prevention, and treatment) and five population-age groups spanning from reproductive and newborn to older adults (≥65 years). Effective coverage indicators were based on intervention coverage or outcome-based measures such as mortality-to-incidence ratios to approximate access to quality care; outcome-based measures were transformed to values on a scale of 0–100 based on the 2·5th and 97·5th percentile of location-year values. We constructed the UHC effective coverage index by weighting each effective coverage indicator relative to its associated potential health gains, as measured by disability-adjusted life-years for each location-year and population-age group. For three tests of validity (content, known-groups, and convergent), UHC effective coverage index performance was generally better than that of other UHC service coverage indices from WHO (ie, the current metric for SDG indicator 3.8.1 on UHC service coverage), the World Bank, and GBD 2017. We quantified frontiers of UHC effective coverage performance on the basis of pooled health spending per capita, representing UHC effective coverage index levels achieved in 2019 relative to country-level government health spending, prepaid private expenditures, and development assistance for health. To assess current trajectories towards the GPW13 UHC billion target—1 billion more people benefiting from UHC by 2023—we estimated additional population equivalents with UHC effective coverage from 2018 to 2023. Globally, performance on the UHC effective coverage index improved from 45·8 (95% uncertainty interval 44·2–47·5) in 1990 to 60·3 (58·7–61·9) in 2019, yet country-level UHC effective coverage in 2019 still spanned from 95 or higher in Japan and Iceland to lower than 25 in Somalia and the Central African Republic. Since 2010, sub-Saharan Africa showed accelerated gains on the UHC effective coverage index (at an average increase of 2·6% [1·9–3·3] per year up to 2019); by contrast, most other GBD super-regions had slowed rates of progress in 2010–2019 relative to 1990–2010. Many countries showed lagging performance on effective coverage indicators for non-communicable diseases relative to those for communicable diseases and maternal and child health, despite non-communicable diseases accounting for a greater proportion of potential health gains in 2019, suggesting that many health systems are not keeping pace with the rising non-communicable disease burden and associated population health needs. In 2019, the UHC effective coverage index was associated with pooled health spending per capita (r=0·79), although countries across the development spectrum had much lower UHC effective coverage than is potentially achievable relative to their health spending. Under maximum efficiency of translating health spending into UHC effective coverage performance, countries would need to reach $1398 pooled health spending per capita (US$ adjusted for purchasing power parity) in order to achieve 80 on the UHC effective coverage index. From 2018 to 2023, an estimated 388·9 million (358·6–421·3) more population equivalents would have UHC effective coverage, falling well short of the GPW13 target of 1 billion more people benefiting from UHC during this time. Current projections point to an estimated 3·1 billion (3·0–3·2) population equivalents still lacking UHC effective coverage in 2023, with nearly a third (968·1 million [903·5–1040·3]) residing in south Asia. The present study demonstrates the utility of measuring effective coverage and its role in supporting improved health outcomes for all people—the ultimate goal of UHC and its achievement. Global ambitions to accelerate progress on UHC service coverage are increasingly unlikely unless concerted action on non-communicable diseases occurs and countries can better translate health spending into improved performance. Focusing on effective coverage and accounting for the world's evolving health needs lays the groundwork for better understanding how close—or how far—all populations are in benefiting from UHC. Bill & Melinda Gates Foundation.