Phase II trial of cytarabine and mitoxantrone with devimistat in acute myeloid leukemia

Pharmacological Insights: Mitochondrial ROS Generation by FNC (Azvudine) in Dalton's Lymphoma Cells Revealed by Super Resolution Imaging

Nucleoside analogs are a common form of chemotherapy that disrupts DNA replication and repair, leading to cell cycle arrest and apoptosis. Reactive oxygen species (ROS) production is a significant mechanism through which these drugs exert their anticancer effects. This study investigated a new nucleoside analog called FNC or Azvudine, and its impact on ROS production and cell viability in Dalton's lymphoma (DL) cells. The study found that FNC treatment resulted in a time- and dose-dependent increase in ROS levels in DL cells. After 15 and 30 min of treatment with 2 and 1 mg/ml of FNC, mitochondrial ROS production was observed in DL cells. Furthermore, prolonged exposure to FNC caused structural alterations and DNA damage in DL cells. The results suggest that FNC's ability to impair DL cell viability may be due to its induction of ROS production and indicate a need for further investigation.

Mitoxantrone encapsulated photosensitizer nanomicelle as carrier-free theranostic nanomedicine for near-infrared fluorescence imaging-guided chemo-photodynamic combination therapy on cancer

Combination therapy exhibits higher efficacy than any single therapy, inspiring various nanocarrier-assisted multi-drug co-delivery systems for the combined treatment of cancer. However, most nanocarriers are inert and non-therapeutic and have potential side effects. Herein, an amphiphilic polymer composed of a hydrophobic photosensitizer and hydrophilic poly(ethylene glycol) was employed as the nanocarriers and photosensitizers to encapsulate the chemotherapeutic drug mitoxantrone for chemo-photodynamic combination therapy. The resulting nanodrug consisted solely of pharmacologically active ingredients, thus avoiding potential toxicity induced by inert excipients. This multifunctional nanoplatform demonstrated significantly superior treatment performance compared to monotherapy for colorectal cancer, both in vitro and in vivo, achieving near-infrared fluorescence imaging-mediated chemo-photodynamic combined eradication of malignancy.

Metabolic vulnerability of cancer stem cells and their niche

Cancer stem cells (CSC) are the leading cause of the failure of anti-tumor treatments. These aggressive cancer cells are preserved and sustained by adjacent cells forming a specialized microenvironment, termed niche, among which tumor-associated macrophages (TAMs) are critical players. The cycle of tricarboxylic acids, fatty acid oxidation path, and electron transport chain have been proven to play central roles in the development and maintenance of CSCs and TAMs. By improving their oxidative metabolism, cancer cells are able to extract more energy from nutrients, which allows them to survive in nutritionally defective environments. Because mitochondria are crucial bioenergetic hubs and sites of these metabolic pathways, major hopes are posed for drugs targeting mitochondria. A wide range of medications targeting mitochondria, electron transport chain complexes, or oxidative enzymes are currently investigated in phase 1 and phase 2 clinical trials against hard-to-treat tumors. This review article aims to highlight recent literature on the metabolic adaptations of CSCs and their supporting macrophages. A focus is provided on the resistance and dormancy behaviors that give CSCs a selection advantage and quiescence capacity in particularly hostile microenvironments and the role of TAMs in supporting these attitudes. The article also describes medicaments that have demonstrated a robust ability to disrupt core oxidative metabolism in preclinical cancer studies and are currently being tested in clinical trials.

Transcription factor E2F3 activates CDC25B to regulate DNA damage and promote mitoxantrone resistance in stomach adenocarcinoma

BACKGROUND

CDC25B, as a member of the cell cycle regulating protein family, is located in the cytoplasm and is involved in the transition of the cell cycle and mitosis. CDC25B is highly expressed in various tumors and is a newly discovered oncogene. This study aimed to investigate the impact of CDC25B on mitoxantrone resistance in stomach adenocarcinoma (STAD) and its possible mechanisms.

METHODS

This study analyzed the expression of CDC25B and its potential transcription factor E2F3 in STAD, as well as the IC50 values of tumor tissues by bioinformatics analysis. Expression levels of CDC25B and E2F3 in STAD cells were measured by qRT-PCR. MTT was utilized to evaluate cell viability and IC50 values of STAD cells, and comet assay was utilized to analyze the level of DNA damage in STAD cells. Western blot was used to analyze the expression of DNA damage-related proteins. The targeting relationship between E2F3 and CDC25B was validated by dual-luciferase and ChIP assays.

RESULTS

Bioinformatics analysis and molecular experiments showed that CDC25B and E2F3 were highly expressed in STAD, and CDC25B was enriched in the mismatch repair and nucleotide excision repair pathways. The IC50 values of tumor tissues with high expression of CDC25B were relatively high. Dual-luciferase and ChIP assays confirmed that CDC25B could be transcriptionally activated by E2F3. Cell experiments revealed that CDC25B promoted mitoxantrone resistance in STAD cells by regulating DNA damage. Further research found that low expression of E2F3 inhibited mitoxantrone resistance in STAD cells by DNA damage, but overexpression of CDC25B reversed the impact of E2F3 knockdown on mitoxantrone resistance in STAD cells.

CONCLUSION

This study confirmed a novel mechanism by which E2F3/CDC25B mediated DNA damage to promote mitoxantrone resistance in STAD cells, providing a new therapeutic target for STAD treatment.

Mitophagy in human health, ageing and disease

Maintaining optimal mitochondrial function is a feature of health. Mitophagy removes and recycles damaged mitochondria and regulates the biogenesis of new, fully functional ones preserving healthy mitochondrial functions and activities. Preclinical and clinical studies have shown that impaired mitophagy negatively affects cellular health and contributes to age-related chronic diseases. Strategies to boost mitophagy have been successfully tested in model organisms, and, recently, some have been translated into clinics. In this Review, we describe the basic mechanisms of mitophagy and how mitophagy can be assessed in human blood, the immune system and tissues, including muscle, brain and liver. We outline mitophagy's role in specific diseases and describe mitophagy-activating approaches successfully tested in humans, including exercise and nutritional and pharmacological interventions. We describe how mitophagy is connected to other features of ageing through general mechanisms such as inflammation and oxidative stress and forecast how strengthening research on mitophagy and mitophagy interventions may strongly support human health.

Aldose reductase and cancer metabolism: The master regulator in the limelight

It is strongly established that metabolic reprogramming mediates the initiation, progression, and metastasis of a variety of cancers. However, there is no common biomarker identified to link the dysregulated metabolism and cancer progression. Recent studies strongly advise the involvement of aldose reductase (AR) in cancer metabolism. AR-mediated glucose metabolism creates a Warburg-like effect and an acidic tumour microenvironment in cancer cells. Moreover, AR overexpression is associated with the impairment of mitochondria and the accumulation of free fatty acids in cancer cells. Further, AR-mediated reduction of lipid aldehydes and chemotherapeutics are involved in the activation of factors promoting proliferation and chemo-resistance. In this review, we have delineated the possible mechanisms by which AR modulates cellular metabolism for cancer proliferation and survival. An in-depth understanding of cancer metabolism and the role of AR might lead to the use of AR inhibitors as metabolic modulating agents for the therapy of cancer.

The role of cancer cell bioenergetics in dormancy and drug resistance

While anti-cancer drug treatments are often effective for the clinical management of cancer, these treatments frequently leave behind drug-tolerant persister cancer cells that can ultimately give rise to recurrent disease. Such persistent cancer cells can lie dormant for extended periods of time, going undetected by conventional clinical means. Understanding the mechanisms that such dormant cancer cells use to survive, and the mechanisms that drive emergence from dormancy, is critical to the development of improved therapeutic strategies to prevent and manage disease recurrence. Cancer cells often exhibit metabolic alterations compared to their non-transformed counterparts. An emerging body of evidence supports the notion that dormant cancer cells also have unique metabolic adaptations that may offer therapeutically targetable vulnerabilities. Herein, we review mechanisms through which cancer cells metabolically adapt to persist during drug treatments and develop drug resistance. We also highlight emerging therapeutic strategies to target dormant cancer cells via their metabolic features.

Pyruvate Dehydrogenase Inhibition Leads to Decreased Glycolysis, Increased Reliance on Gluconeogenesis and Alternative Sources of Acetyl-CoA in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive disease characterized by poor outcomes and therapy resistance. Devimistat is a novel agent that inhibits pyruvate dehydrogenase complex (PDH). A phase III clinical trial in AML patients combining devimistat and chemotherapy was terminated for futility, suggesting AML cells were able to circumvent the metabolic inhibition of devimistat. The means by which AML cells resist PDH inhibition is unknown. AML cell lines treated with devimistat or deleted for the essential PDH subunit, PDHA, showed a decrease in glycolysis and decreased glucose uptake due to a reduction of the glucose transporter GLUT1 and hexokinase II. Both devimistat-treated and PDHA knockout cells displayed increased sensitivity to 2-deoxyglucose, demonstrating reliance on residual glycolysis. The rate limiting gluconeogenic enzyme phosphoenolpyruvate carboxykinase 2 (PCK2) was significantly upregulated in devimistat-treated cells, and its inhibition increased sensitivity to devimistat. The gluconeogenic amino acids glutamine and asparagine protected AML cells from devimistat. Non-glycolytic sources of acetyl-CoA were also important with fatty acid oxidation, ATP citrate lyase (ACLY) and acyl-CoA synthetase short chain family member 2 (ACSS2) contributing to resistance. Finally, devimistat reduced fatty acid synthase (FASN) activity. Taken together, this suggests that AML cells compensate for PDH and glycolysis inhibition by gluconeogenesis for maintenance of essential glycolytic intermediates and fatty acid oxidation, ACLY and ACSS2 for non-glycolytic production of acetyl-CoA. Strategies to target these escape pathways should be explored in AML.

Resistance to energy metabolism - targeted therapy of AML cells residual in the bone marrow microenvironment

In response to the changing availability of nutrients and oxygen in the bone marrow microenvironment, acute myeloid leukemia (AML) cells continuously adjust their metabolic state. To meet the biochemical demands of their increased proliferation, AML cells strongly depend on mitochondrial oxidative phosphorylation (OXPHOS). Recent data indicate that a subset of AML cells remains quiescent and survives through metabolic activation of fatty acid oxidation (FAO), which causes uncoupling of mitochondrial OXPHOS and facilitates chemoresistance. For targeting these metabolic vulnerabilities of AML cells, inhibitors of OXPHOS and FAO have been developed and investigated for their therapeutic potential. Recent experimental and clinical evidence has revealed that drug-resistant AML cells and leukemic stem cells rewire metabolic pathways through interaction with BM stromal cells, enabling them to acquire resistance against OXPHOS and FAO inhibitors. These acquired resistance mechanisms compensate for the metabolic targeting by inhibitors. Several chemotherapy/targeted therapy regimens in combination with OXPHOS and FAO inhibitors are under development to target these compensatory pathways.

Integrated bioinformatic analysis of mitochondrial metabolism-related genes in acute myeloid leukemia

Background

Acute myeloid leukemia (AML) is a common hematologic malignancy characterized by poor prognoses and high recurrence rates. Mitochondrial metabolism has been increasingly recognized to be crucial in tumor progression and treatment resistance. The purpose of this study was to examined the role of mitochondrial metabolism in the immune regulation and prognosis of AML.

Methods

In this study, mutation status of 31 mitochondrial metabolism-related genes (MMRGs) in AML were analyzed. Based on the expression of 31 MMRGs, mitochondrial metabolism scores (MMs) were calculated by single sample gene set enrichment analysis. Differential analysis and weighted co-expression network analysis were performed to identify module MMRGs. Next, univariate Cox regression and the least absolute and selection operator regression were used to select prognosis-associated MMRGs. A prognosis model was then constructed using multivariate Cox regression to calculate risk score. We validated the expression of key MMRGs in clinical specimens using immunohistochemistry (IHC). Then differential analysis was performed to identify differentially expressed genes (DEGs) between high- and low-risk groups. Functional enrichment, interaction networks, drug sensitivity, immune microenvironment, and immunotherapy analyses were also performed to explore the characteristic of DEGs.

Results

Given the association of MMs with prognosis of AML patients, a prognosis model was constructed based on 5 MMRGs, which could accurately distinguish high-risk patients from low-risk patients in both training and validation datasets. IHC results showed that MMRGs were highly expressed in AML samples compared to normal samples. Additionally, the 38 DEGs were mainly related to mitochondrial metabolism, immune signaling, and multiple drug resistance pathways. In addition, high-risk patients with more immune-cell infiltration had higher Tumor Immune Dysfunction and Exclusion scores, indicating poor immunotherapy response. mRNA-drug interactions and drug sensitivity analyses were performed to explore potential druggable hub genes. Furthermore, we combined risk score with age and gender to construct a prognosis model, which could predict the prognosis of AML patients.

Conclusion

Our study provided a prognostic predictor for AML patients and revealed that mitochondrial metabolism is associated with immune regulation and drug resistant in AML, providing vital clues for immunotherapies.

Identification of Dihydrolipoamide Dehydrogenase as Potential Target of Vemurafenib-Resistant Melanoma Cells

BACKGROUND

Despite recent improvements in therapy, the five-year survival rate for patients with advanced melanoma is poor, mainly due to the development of drug resistance. The aim of the present study was to investigate the mechanisms underlying this phenomenon, applying proteomics and structural approaches to models of melanoma cells.

METHODS

Sublines from two human (A375 and SK-MEL-28) cells with acquired vemurafenib resistance were established, and their proteomic profiles when exposed to denaturation were identified through LC-MS/MS analysis. The pathways derived from bioinformatics analyses were validated by in silico and functional studies.

RESULTS

The proteomic profiles of resistant melanoma cells were compared to parental counterparts by taking into account protein folding/unfolding behaviors. Several proteins were found to be involved, with dihydrolipoamide dehydrogenase (DLD) being the only one similarly affected by denaturation in all resistant cell sublines compared to parental ones. DLD expression was observed to be increased in resistant cells by Western blot analysis. Protein modeling analyses of DLD's catalytic site coupled to in vitro assays with CPI-613, a specific DLD inhibitor, highlighted the role of DLD enzymatic functions in the molecular mechanisms of BRAFi resistance.

CONCLUSIONS

Our proteomic and structural investigations on resistant sublines indicate that DLD may represent a novel and potent target for overcoming vemurafenib resistance in melanoma cells.

Therapeutic Drug-Induced Metabolic Reprogramming in Glioblastoma

Glioblastoma WHO IV (GBM), the most common primary brain tumor in adults, is a heterogenous malignancy that displays a reprogrammed metabolism with various fuel sources at its disposal. Tumor cells primarily appear to consume glucose to entertain their anabolic and catabolic metabolism. While less effective for energy production, aerobic glycolysis (Warburg effect) is an effective means to drive biosynthesis of critical molecules required for relentless growth and resistance to cell death. Targeting the Warburg effect may be an effective venue for cancer treatment. However, past and recent evidence highlight that this approach may be limited in scope because GBM cells possess metabolic plasticity that allows them to harness other substrates, which include but are not limited to, fatty acids, amino acids, lactate, and acetate. Here, we review recent key findings in the literature that highlight that GBM cells substantially reprogram their metabolism upon therapy. These studies suggest that blocking glycolysis will yield a concomitant reactivation of oxidative energy pathways and most dominantly beta-oxidation of fatty acids.