Diffuse midline gliomas (DMGs), including diffuse intrinsic pontine gliomas (DIPGs), are universally fatal pediatric brain tumors with no effective treatments. DIPG tumors actively utilize mitochondrial oxidative phosphorylation (OXPHOS). Inhibition of Complex I (a core OXPHOS component) by phenformin radiosensitizes DIPG in vitro and in vivo. However, phenformin’s clinical application is limited by its risk of lactic acidosis. We investigated whether co-administration of the pyruvate-dehydrogenase-kinase (PDK) inhibitor dichloroacetate (DCA) can mitigate phenformin-induced acidosis while enhancing its anti-tumor activity. Patient-derived DIPG cells (SU-DIPG17, HSJD-DIPG007, SU-DIPG-VI) were treated with phenformin (0.625 mM), DCA (25 mM) or both. Mitochondrial and glycolytic flux (oxygen consumption rate (OCR) / extracellular acidification rate (ECAR)), ATP production, Reactive Oxygen Species (ROS), cell-cycle and apoptosis were quantified alongside RNA-seq and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS)/MS metabolomics. Hypoxia was measured in neurospheres using fluorescence. Radiosensitization was assessed by γ-H2AX foci and clonogenic survival. In vivo, HSJD-DIPG007 orthotopic xenografts received phenformin (125 mg/kg/day) and DCA (250 mg/kg/day) by oral gavage for 4 weeks, alone or with focal brain-stem irradiation (2 Gy × 10); tumor immunohistochemistry and survival were recorded. DCA alone shifted glucose metabolism from glycolysis to oxidative phosphorylation (OXPHOS), reducing ECAR and intracellular lactate. When combined with phenformin, DCA significantly suppressed phenformin-induced glycolysis and ECAR while further reducing ATP. In vitro, this combination induced synergistic cell-cycle arrest, apoptosis, and ROS-induced DNA damage. Multi-omics integration revealed coordinated repression of glycolytic/ hypoxia-inducible factor (HIF) programs and diversion of glucose into redox-supportive pentose-phosphate pathways. Hypoxic staining confirmed reduced hypoxia and HIF-1α in 3D neurospheroids. The combination produced additional in vitro radiosensitization, with the phenformin + DCA + radiation triple regimen achieving the greatest γ-H2AX persistence and clonogenic kill. In mice, the triple combination schedule incurred systemic toxicity, reflected from weight loss, and did not extend survival over 4 weeks treatment. DCA effectively counteracts phenformin-induced lactic acidosis in vitro yet heightens metabolic stress and radiosensitization in DIPG cells, providing proof-of-concept that a carefully chosen metabolic partner can boost tumor control. However, weight loss in vivo limited the length of treatment schedule and optimizing dose and schedule, or selecting safer mitochondrial inhibitors with PDK blockade, will be essential next steps before determining in vivo efficacy of this metabolic strategy. Diffuse midline gliomas, including diffuse intrinsic pontine glioma, are aggressive childhood brain tumors with no effective treatments. These tumors depend on energy produced by mitochondria, making mitochondrial metabolism a promising target for new therapies. However, drugs like phenformin, which block mitochondrial metabolism, can cause dangerous lactic acid buildup, limiting their clinical use. To address this, our study combined phenformin with dichloroacetate, a drug that targets glucose metabolism and can reduce lactic acidosis. This combination successfully lowered acid buildup, disrupted tumor cell metabolism, and enhanced cancer cell sensitivity to radiation in vitro, a key treatment for these tumors. However, a pilot in vivo study highlights the challenges that will need to be overcome in dosing and toxicity when combining multiple metabolic drugs with radiation.

BackgroundAcute myeloid leukemia (AML) is a devastating hematological malignancy with limited therapeutic options and poor survival outcomes. Therefore, the development of novel and selective anti-AML therapies is needed. 6-methoxydihydroavicine (6ME), a benzophenanthridine alkaloid, imparted selective AML cell death in vitro and in vivo. Mechanistically, 6ME inhibited fatty acid oxidation (FAO) by binding to and decreasing the activity of PPARδ, a transcription factor involved in FAO.MethodsAML cell lines and patient-derived cells were used to assess the activity of 6ME in vitro and in vivo. Computational methods, immunoblotting, and co-IP-HPLC analysis assessed the molecular target, and cellular consequence of 6ME activity.Results6ME induced cytotoxicity of AML cell lines (IC50: 1.0 ± 0.13 μM) and patient-derived cells while sparing normal hematopoietic cells. Mouse engraftment studies showed that 6ME (5 mg/kg, three times/week for 4 weeks) selectively reduced patient-derived AML cell engraftment without affecting hematopoietic cell engraftment or imparting toxicity. Mechanistically, 6ME bound to and inhibited PPARδ leading to downregulated FAO gene expression (i.e., CD36 and CPT2) and reduced fatty acid cellular uptake resulting in FAO inhibition.ConclusionPharmacological inhibition of PPARδ with 6ME is a novel approach to inducing selective death in AML.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40170-025-00402-5.

Lipid accumulation is associated with breast cancer metastasis. However, the mechanisms underlying how breast cancer cells increase lipid stores and their functional role in disease progression remain incompletely understood. Herein we quantified changes in lipid metabolism and characterized cytoplasmic lipid droplets in metastatic versus non-metastatic breast cancer cells. 14C-labeled palmitate was used to determine differences in fatty acid (FA) uptake and oxidation. Despite similar levels of palmitate uptake, metastatic cells increase lipid accumulation and oxidation of endogenous FAs compared to non-metastatic cells. Isotope tracing also demonstrated that metastatic cells support increased de novo lipogenesis by converting higher levels of glutamine and glucose into the FA precursor, citrate. Consistent with this, metastatic cells displayed increased levels of fatty acid synthase (FASN) and de novo lipogenesis. Genetic depletion or pharmacologic inhibition of FASN reduced cell migration, survival in anoikis assays, and in vivo metastasis. Finally, global proteomic analysis indicated that proteins involved in proteasome function, mitotic cell cycle, and intracellular protein transport were reduced following FASN inhibition of metastatic cells. Overall, these studies demonstrate that breast cancer metastases accumulate FAs by increasingde novo lipogenesis, storing TAG as cytoplasmic lipid droplets, and catabolizing these stores to drive several FAO-dependent steps in metastasis.

BackgroundHuman cells can synthesize methionine from homocysteine and folate-coupled methyl groups via the B12-dependent enzyme methionine synthase (MTR). Yet, it has been known for decades that cancer cells fail to grow when methionine is replaced by homocysteine, a phenomenon known as methionine dependence. The underlying mechanism remains unknown.MethodsCancer cell lines were cultured with homocysteine in place of methionine, and growth responses were measured. Revertant cells capable of growing in homocysteine were generated through long-term culture with high B12 and analyzed using single-cell RNA-seq. Metabolite uptake/release was measured using isotope dilution and MTR activity was assessed using metabolic flux analysis (MFA). Functional rescue experiments were performed by overexpressing the B12-independent methionine synthase enzyme.ResultsWe report evidence that methionine dependence is caused by low MTR activity secondary to a B12 deficiency. High levels of the B12 cofactor were required to revert methionine-dependent cancer cells to grow on homocysteine. The adapted “revertant” cells display gene expression signatures consistent with reduced invasion and metastasis. Metabolic flux analysis indicated that methionine-dependent cells do not fully activate MTR when cultured in homocysteine. High concentrations of homocysteine partially rescued growth of methionine-dependent cells. Expression of a B12-independent methionine synthase enzyme in cancer cells restored growth on homocysteine and normalized the SAM:SAH ratio, while overexpression of the B12-dependent human enzyme had no effect.ConclusionMethionine dependence in cancer can be driven by low MTR activity secondary to B12 deficiency, at least in the cell lines studied. This mechanistic insight resolves a long-standing question in cancer metabolism and may open new avenues for exploiting the phenomenon for cancer therapy.

Breast cancer remains the most prevalent malignancy among women globally, with its complexity linked to genetic variations and metabolic alterations within tumor cells. This study investigates the role of fumarate hydratase (FH), a key enzyme in the tricarboxylic acid (TCA) cycle, in breast cancer progression. Our findings reveal that FH mRNA and protein levels are significantly upregulated in breast cancer tissues and correlate with poor patient prognosis and aggressive tumor characteristics. Using in vitro and in vivo models, we demonstrate that FH overexpression enhances breast cancer cell proliferation, migration, and invasion through metabolic reprogramming and by increasing reactive oxygen species (ROS) production. Furthermore, we identify matrix metalloproteinase 1 (MMP1) as a downstream effector of FH, linked to p21 downregulation, elucidating a novel regulatory pathway influencing tumor behavior. Interestingly, unlike its tumor-suppressing role in other cancer types, this study highlights FH's oncogenic potential in breast cancer. Our results suggest that FH enhances cancer cell viability and aggressiveness via both catalytic and non-catalytic mechanisms. This work not only underscores the metabolic adaptations of breast cancer cells but also proposes FH as a potential biomarker and therapeutic target for breast cancer management.

IntroductionThis study aimed to evaluate the metabolic differences between MM cells derived from patients with elevated serum LDH levels and those without elevated serum LDH levels to identify biological differences that could be exploited for therapeutic purposes.MethodsWe performed transcriptome assessments of CD138 + MM cells derived from patients with elevated serum LDH levels compared to those without elevated serum LDH levels and validated the findings in a larger public dataset. Functional metabolic assessments of our findings were performed using a combination of stable isotope resolved metabolomics (SIRM), bioenergetic flux measurement assays, and live cell analysis in human myeloma cell lines and primary MM patient cells.ResultsWe identified SLC16A1, responsible for the formation of MCT1, a well-defined bi-directional transporter of lactate in and out of a cell with a predilection to importing extracellular lactate, as differentially expressed between the two groups. This finding was functionally confirmed by higher membranous MCT1 protein expression and SIRM on MM cells derived from patients with elevated serum LDH levels compared to those without elevated serum LDH levels. Finally, disrupting lactate transport in and out of CD138 + MM cells was maximally achievable only with dual inhibition of MCT1 and its partner, MCT4, which was preferentially more cytotoxic in MM cells derived from patients with elevated serum levels of LDH.ConclusionMCT1 mRNA and protein expression distinguish MM cells derived from patients with elevated serum LDH levels from those without elevated serum LDH levels. However, only dual inhibition of MCT1 and MCT4 can disrupt lactate transport in multiple myeloma (MM) cells, with preferential cytotoxicity in MM cells from patients with high serum LDH levels.

Chemoresistance remains a major challenge in the effective treatment of colorectal cancer (CRC), contributing to poor patient outcomes. While the molecular mechanisms underlying chemoresistance are complex and multifaceted, emerging evidence suggests that altered mitochondrial function and hormone signaling play crucial roles. In this study, we investigated the role of CYP19A1, a key enzyme in estrogen biosynthesis, in regulating chemoresistance in CRC. Using a combination of in vitro functional assays, transcriptomic analysis, and clinical data mining, we demonstrate that CYP19A1 expression is significantly upregulated in CRC cells and patient-derived samples compared to normal controls. Mechanistically, we found that CYP19A1 regulates chemoresistance through modulation of mitochondrial function and complex I activity, which is mediated by CYP19A1-dependent estrogen biosynthesis. Notably, targeted inhibition of CYP19A1 and complex I using specific inhibitors effectively reversed the chemoresistance of CRC cells to chemotherapeutic drugs. Moreover, analysis of the TCGA CRC dataset revealed that high CYP19A1 expression correlates with poor overall survival in chemotherapy-treated patients. Taken together, our findings uncover a novel role for CYP19A1 in regulating chemoresistance in CRC through modulation of mitochondrial function and estrogen signaling, and highlight the potential of targeting the CYP19A1/estrogen/complex I axis as a therapeutic strategy to overcome chemoresistance and improve patient outcomes.

BackgroundDespite technological advances in radiotherapy, cancer cells at the tumor margin and in diffusive infiltrates can receive subcytotoxic doses of photons. Even if only a minority of cancer cells are concerned, phenotypic consequences could be important considering that mitochondrial DNA (mtDNA) is a primary target of radiation and that damage to mtDNA can persist. In turn, mitochondrial dysfunction associated with enhanced mitochondrial ROS (mtROS) production could promote cancer cell migration out of the irradiation field in a natural attempt to escape therapy. In this study, using MCF7 and MDA-MB-231 human breast cancer cells as models, we aimed to elucidate the molecular mechanisms supporting a mitochondrial contribution to cancer cell migration induced by subclinical doses of irradiation (< 2 Gy).MethodsMitochondrial dysfunction was tested using mtDNA multiplex PCR, oximetry, and ROS-sensitive fluorescent reporters. Migration was tested in transwells 48 h after irradiation in the presence or absence of inhibitors targeting specific ROS or downstream effectors. Among tested inhibitors, we designed a mitochondria-targeted version of human catalase (mtCAT) to selectively inactivate mitochondrial H2O2.ResultsPhoton irradiation at subclinical doses (0.5 Gy for MCF7 and 0.125 Gy for MDA-MB-231 cells) sequentially affected mtDNA levels and/or integrity, increased mtROS production, increased MAP2K1/MEK1 gene expression, activated ROS-sensitive transcription factors NF-κB and AP1 and stimulated breast cancer cell migration. Targeting mtROS pharmacologically by MitoQ or genetically by mtCAT expression mitigated migration induced by a subclinical dose of irradiation.ConclusionSubclinical doses of photon irradiation promote human breast cancer migration, which can be countered by selectively targeting mtROS.

IntroductionMetformin and statins are considered as potential agents for prevention of breast cancer, however, existing evidence does not uniformly substantiate this claim, and the data is scarce concerning their interaction in relation to breast cancer risk. This study aims to investigate whether the effect of metformin on breast cancer incidence varied by statin use among women with type 2 diabetes mellitus (T2DM).MethodsThis study included women with T2DM, without a history of cancers, and followed up for more than one year from the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) for the period 1998–2014. The dataset was structured using a person-time approach, where the cumulative medication usage was annually updated for each person. The extended Cox proportional hazards models were employed, reporting adjusted hazard ratios (HR) with 95% confidence intervals (CI).ResultsDuring a median follow-up of 5 years, 515 of 29,498 women received a breast cancer diagnosis. Each additional year of metformin or statins use corresponded to a decrease in breast cancer incidence, while the magnitude attenuated over time. Noteworthily, statin use modified the effect of metformin on breast cancer incidence. For instance, after 5 years of follow-up, one-year increase of metformin use among women who used statins for 3 years was linked to a substantially reduced breast cancer risk (HR, 95% CI: 0.88, 0.84–0.93), however, there was no significant decrease in risk for those non-statins users (HR, 95% CI: 0.96, 0.89–1.04).ConclusionsExtending metformin or statin usage by one year conferred breast cancer protection in women with T2DM. Enhanced protective effect of metformin was observed among those who also use statins. These results suggest the potential of combined metformin and statin therapy as promising breast cancer prevention strategies.

BackgroundThe C-reactive protein (CRP)-triglyceride-glucose (TyG) index (CTI), which is a measure representing the level of inflammation and insulin resistance (IR), is related to poor cancer prognosis; however, the CTI has not been validated in patients with cancer cachexia. Thus, this study aimed to explore the potential clinical value of the CTI in patients with cancer cachexia.MethodsIn this study, our prospective multicenter cohort included 1411 patients with cancer cachexia (mean age 59.45 ± 11.38, 63.3% male), which was a combined analysis of multiple cancer types. We randomly selected 30% of the patients for the internal test cohort (mean age 58.90 ± 11.22% 61.4% male). Additionally, we included 307 patients with cancer cachexia in the external validation cohort (mean age 61.16 ± 11, 58.5% male). Receiver operating characteristic (ROC) and calibration curves were performed to investigate the prognostic value of CTI. The prognostic value of the CTI was also investigated performing univariate and multivariate survival analyses.ResultsThe survival curve indicated that the CTI showed a significant prognostic value in the total, internal, and external validation cohorts. Prognostic ROC curves and calibration curves revealed that the CTI showed good consistency in predicting the survival of patients with cancer cachexia. Multivariate survival analysis showed that an elevated CTI increased the risk of death by 22% (total cohort, 95% confidence interval [CI] = 1.13–1.33), 34% (internal test cohort, 95%CI = 1.11–1.62), and 35% (external validation cohort, 95%CI = 1.14–1.59) for each increase in the standard deviation of CTI. High CTI reliably predicted shorter survival (total cohort, hazard ratio [HR] = 1.45, 95%CI = 1.22–1.71; internal test cohort, HR = 1.62, 95%CI = 1.12–2.36; external validation cohort, HR = 1.61, 95%CI = 1.15–2.26). High CTI significantly predicted shorter survival in different tumor subgroups, such as esophageal [HR = 2.11, 95%CI = 1.05–4.21] and colorectal cancer [HR = 2.29, 95%CI = 1.42–3.71]. The mediating effects analysis found that the mediating proportions of PGSGA, ECOG PS, and EORTC QLQ-C30 on the direct effects of CTI were 21.72%, 19.63%, and 11.61%, respectively We found that there was a significant positive correlation between the CTI and 90-day [HR = 2.48, 95%CI = 1.52–4.14] and 180-day mortality [HR = 1.77,95%CI = 1.24–2.55] in patients with cancer cachexia.ConclusionThe CTI can predict the short- and long-term survival of patients with cancer cachexia and provide a useful prognostic tool for clinical practice.