Mitochondria: The metabolic switch of cellular oncogenic transformation

Short-term regulation of TSFM level does not alter amyloidogenesis and mitochondrial function in type-specific cells

BACKGROUND

Mitochondrial Ts translation elongation factor (TSFM) is an enzyme that catalyzes exchange of guanine nucleotides. By forming a complex with mitochondrial Tu translation elongation factor (TUFM), TSFM participates in mitochondrial protein translation. We have previously reported that TUFM regulates translation of beta-site APP cleaving enzyme 1 (BACE1) via ROS (reactive oxygen species)-dependent mechanism, suggesting a potential role in amyloid precursor protein (APP) processing associated with Alzheimer's disease (AD), which led to the speculation that TSFM may regulate APP processing in a similar way to TUFM.

METHODS AND RESULTS

Here, we report that in cultured cells, knockdown or overexpression TSFM did not change protein levels in BACE1 and APP. Besides, the levels of cytoplasmic ROS and mitochondrial superoxide, in addition to ATP level, cell viability and mitochondrial membrane potential were not significantly altered by TSFM knockdown in the short term. Further transcriptome analysis revealed that expression of majority of mitochondrial genes were not remarkably changed by TSFM silencing. The possibility of TSFM involved in cardiomyopathy and cancer development was uncovered using bioinformatics analysis.

CONCLUSIONS

Collectively, short-term regulation of TSFM level in cultured cells does not cause a significant change in proteins involved in APP processing, levels in ROS and ATP associated with mitochondrial function. Whereas our study could contribute to comprehend certain clinical features of TSFM mutations, the roles of TSFM in cardiomyopathy and cancer development might deserve further investigation.

The down-regulation of GADD45B leads to a conversion of cellular oxidative phosphorylation to glycolysis and promotes the progression of bladder cancer

Background

The predominant feature of cancer cells during the process of carcinogenesis is the inclination towards glycolytic metabolism rather than mitochondrial oxidative phosphorylation. Nevertheless, there is a scarcity of research investigating the correlation between bladder cancer and mitochondrial energy metabolism.

Methods

A qPCR array comprising 90 genes associated with mitochondrial oxidative phosphorylation was employed to discern metabolic disparities between three sets of bladder cancer tissue and adjacent normal tissue. Wound healing and transwell assays were utilized to assess cell migration and invasion capabilities, respectively. Colony formation assays were conducted to ascertain the tumorigenic potential of the cells. The proliferative capacity of the cells was examined through in vitro CCK-8 assays. Additionally, nude mouse models were established to evaluate the impact of bladder tumor cells on in vivo proliferation. The Seahorse XFe96 Analyzer was utilized to quantify mitochondrial oxidative phosphorylation, while the levels of glucose-6-phosphate and pyruvate were assessed to evaluate glycolysis.

Results

Examination of qPCR array data demonstrated a noteworthy inhibition of mitochondrial oxidative phosphorylation in bladder cancer tissue, as evidenced by the down-regulation of a majority of genes associated with mitochondrial energy metabolism. Notably, GADD45B may potentially exert a significant influence on bladder cancer development, warranting further investigation. The down-regulation of GADD45B in bladder cancer cells resulted in impaired mitochondrial respiration and elevated levels of glycolysis, thereby enhancing cell migration and invasion. Conversely, up-regulation of GADD45B had the opposite effect. Furthermore, over-expression of GADD45B inhibited tumor proliferation and tumorigenesis in both in vitro and in vivo settings.

Conclusion

These findings from our study indicate that the down-regulation of GADD45B promotes the shift of cell mitochondrial oxidative phosphorylation towards glycolysis, thereby facilitating the progression of bladder cancer.

Verteporfin fluorescence in antineoplastic-treated pancreatic cancer cells found concentrated in mitochondria

BACKGROUND

Traditional treatments for pancreatic cancer (PC) are inadequate. Photodynamic therapy (PDT) is non-invasive, and proven safe to kill cancer cells, including PC. However, the mitochondrial concentration of the photosensitizer, such as verteporfin, is key.

AIM

To investigate the distribution of fluorescence of verteporfin in PC cells treated with antitumor drugs, post-PDT.

METHODS

Workable survival rates of PC cells (AsPC-1, BxPC-3) were determined with chemotherapy [doxorubicin (DOX) and gemcitabine (GEM)] and non-chemotherapy [sirolimus (SRL) and cetuximab (CTX)] drugs in vitro, with or without verteporfin, as measured via MTT, flow cytometry, and laser confocal microscopy. Reduced cell proliferation was associated with GEM that was more enduring compared with DOX. Confocal laser microscopy allowed observation of GEM- and verteporfin-treated PC cells co-stained with 4',6-diamidino-2-phenylindole and MitoTracker Green to differentiate living and dead cells and subcellular localization of verteporfin, respectively.

RESULTS

Cell survival significantly dropped upon exposure to either chemotherapy drug, but not to SRL or CTX. Both cell lines responded similarly to GEM. The intensity of fluorescence was associated with the concentration of verteporfin. Additional experiments using GEM showed that survival rates of the PC cells treated with 10 μmol/L verteporfin (but not less) were significantly lower relative to nil verteporfin. Living and dead stained cells treated with GEM were distinguishable. After GEM treatment, verteporfin was observed primarily in the mitochondria.

CONCLUSION

Verteporfin was observed in living cells. In GEM -treated human PC cells, verteporfin was particularly prevalent in the mitochondria. This study supports further study of PDT for the treatment of PC after neoadjuvant chemotherapy.

Concurrent inhibition of pBADS99 synergistically improves MEK inhibitor efficacy in KRASG12D-mutant pancreatic ductal adenocarcinoma

Therapeutic targeting of KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) has remained a significant challenge in clinical oncology. Direct targeting of KRAS has proven difficult, and inhibition of the KRAS effectors have shown limited success due to compensatory activation of survival pathways. Being a core downstream effector of the KRAS-driven p44/42 MAPK and PI3K/AKT pathways governing intrinsic apoptosis, BAD phosphorylation emerges as a promising therapeutic target. Herein, a positive association of the pBADS99/BAD ratio with higher disease stage and worse overall survival of PDAC was observed. Homology-directed repair of BAD to BADS99A or small molecule inhibition of BADS99 phosphorylation by NCK significantly reduced PDAC cell viability by promoting cell cycle arrest and apoptosis. NCK also abrogated the growth of preformed colonies of PDAC cells in 3D culture. Furthermore, high-throughput screening with an oncology drug library to identify potential combinations revealed a strong synergistic effect between NCK and MEK inhibitors in PDAC cells harboring either wild-type or mutant-KRAS. Mechanistically, both mutant-KRAS and MEK inhibition increased the phosphorylation of BADS99 in PDAC cells, an effect abrogated by NCK. Combined pBADS99-MEK inhibition demonstrated strong synergy in reducing cell viability, enhancing apoptosis, and achieving xenograft stasis in KRAS-mutant PDAC. In conclusion, the inhibition of BADS99 phosphorylation enhances the efficacy of MEK inhibition, and their combined inhibition represents a mechanistically based and potentially effective therapeutic strategy for the treatment of KRAS-mutant PDAC.

Mitochondrial influences on smooth muscle phenotype

Smooth muscle cells transition reversibly between contractile and noncontractile phenotypes in response to diverse influences, including many from mitochondria. Numerous molecules including myocardin, procontractile miRNAs, and the mitochondrial protein prohibitin-2 promote contractile differentiation; this is opposed by mitochondrial reactive oxygen species (mtROS), high lactate concentrations, and metabolic reprogramming induced by mitophagy and/or mitochondrial fission. A major pathway through which vascular pathologies such as oncogenic transformation, pulmonary hypertension, and atherosclerosis cause loss of vascular contractility is by enhancing mitophagy and mitochondrial fission with secondary effects on smooth muscle phenotype. Proproliferative miRNAs and the mitochondrial translocase TOMM40 also attenuate contractile differentiation. Hypoxia can initiate loss of contractility by enhancing mtROS and lactate production while simultaneously depressing mitochondrial respiration. Mitochondria can reduce cytosolic calcium by moving it across the inner mitochondrial membrane via the mitochondrial calcium uniporter, and then through mitochondria-associated membranes to and from calcium stores in the sarcoplasmic/endoplasmic reticulum. Through these effects on calcium, mitochondria can influence multiple calcium-sensitive nuclear transcription factors and genes, some of which govern smooth muscle phenotype, and possibly also the production of genomically encoded mitochondrial proteins and miRNAs (mitoMirs) that target the mitochondria. In turn, mitochondria also can influence nuclear transcription and mRNA processing through mitochondrial retrograde signaling, which is currently a topic of intensive investigation. Mitochondria also can signal to adjacent cells by contributing to the content of exosomes. Considering these and other mechanisms, it is becoming increasingly clear that mitochondria contribute significantly to the regulation of smooth muscle phenotype and differentiation.

Data-independent acquisition for proteomic applications in early-stage endometrial cancer progression

AIM

Most endometrial cancer (EC) patients are diagnosed at an early-stage (FIGO stage I or II), with a favorable prognosis. However, some high-grade, early-stage EC patients have unexpected recurrences and undesirable results, the molecular alterations that underlie these tumors are far from being fully understood. Our goal was to use proteome analysis to examine dysregulated pathways in this specific subgroup of EC.

METHODS

We used data-independent acquisition (DIA) quantitative proteomics to analyze cancer and matched paracancerous tissues from 20 EC patients (10 high-grade and 10 low-grade). Immunohistochemistry (IHC) analysis was used to validate protein expression of six hub genes.

RESULTS

In total, 7107 proteins were quantified, while 225 downregulated and 366 upregulated proteins in high-grade cancer tissues, 130 downregulated and 413 upregulated proteins in high-grade paracancerous tissues. The pathway associated with oxidative phosphorylation (OXPHOS) was upregulated and have similar expression patterns in high-grade EC tissues and matched paracancerous tissues. OXPHOS-related protein, ATP5F1D showed the best classification and diagnostic ability in distinguishing high-grade from low-grade EC. In both cancer and paracancerous tissues, double-label immunofluorescence demonstrated ITGA4 and COL4A1 co-localized at the basal membrane.

CONCLUSIONS

Our present works elucidate that metabolism reprogramming is associated with high-grade, early-stage EC, particularly OXPHOS is upregulated. Noticeably, the paracancerous tissues have undergone molecular changes similar to cancer tissues, maybe they have signal exchange via secreted proteins (ITGA4 and COL4A1). The upregulation of OXPHOS-related proteins may be the potential biomarker for EC diagnosis, and targeting OXPHOS metabolism might be an effective treatment for high-grade, early-stage EC.

Mitochondrial Inherited Disorders and their Correlation with Neurodegenerative Diseases

Mitochondria are essential organelles for the survival of a cell because they produce energy. The cells that need more mitochondria are neurons because they perform a variety of tasks that are necessary to support brain homeostasis. The build-up of abnormal proteins in neurons, as well as their interactions with mitochondrial proteins, or MAM proteins, cause serious health issues. As a result, mitochondrial functions, such as mitophagy, are impaired, resulting in the disorders described in this review. They are also due to mtDNA mutations, which alter the heritability of diseases. The topic of disease prevention, as well as the diagnosis, requires further explanation and exploration. Finally, there are treatments that are quite promising, but more detailed research is needed.

The preventive effects of broccoli bioactives against cancer: Evidence from a validated rat glioma model

The aggressive and incurable diffuse gliomas constitute 80% of malignant brain tumors, and patients succumb to recurrent surgeries and drug resistance. Epidemiological research indicates that substantial consumption of fruits and vegetables diminishes the risk of developing this tumor type. Broccoli consumption has shown beneficial effects in both cancer and neurodegenerative diseases. These effects are partially attributed to the isothiocyanate sulforaphane (SFN), which can regulate the Keap1/Nrf2/ARE signaling pathway, stimulate detoxifying enzymes, and activate cellular antioxidant defense processes. This study employs a C6 rat glioma model to assess the chemoprotective potential of aqueous extracts from broccoli seeds, sprouts, and inflorescences, all rich in SFN, and pure SFN as positive control. The findings reveal that administering a dose of 100 mg/kg of broccoli sprout aqueous extract and 0.1 mg/kg of SFN to animals for 30 days before introducing 1 × 104 cells effectively halts tumor growth and progression. This study underscores the significance of exploring foods abundant in bioactive compounds, such as derivatives of broccoli, for potential preventive integration into daily diets. Using broccoli sprouts as a natural defense against cancer development might seem idealistic, yet this investigation establishes that administering this extract proves to be a valuable approach in designing strategies for glioma prevention. Although the findings stem from a rat glioma model, they offer promising insights for subsequent preclinical and clinical research endeavors.

Small molecule inhibition of TFF3 overcomes tamoxifen resistance and enhances taxane efficacy in ER+ mammary carcinoma

Even though tamoxifen has significantly improved the survival of estrogen receptor positive (ER+) mammary carcinoma (MC) patients, the development of drug resistance with consequent disease recurrence has limited its therapeutic efficacy. Trefoil factor-3 (TFF3) has been previously reported to mediate anti-estrogen resistance in ER+MC. Herein, the efficacy of a small molecule inhibitor of TFF3 (AMPC) in enhancing sensitivity and mitigating acquired resistance to tamoxifen in ER+MC cells was investigated. AMPC induced apoptosis of tamoxifen-sensitive and resistant ER+MC cells and significantly reduced cell survival in 2D and 3D culture in vitro. In addition, AMPC reduced cancer stem cell (CSC)-like behavior in ER+MC cells in a BCL2-dependent manner. Synergistic effects of AMPC and tamoxifen were demonstrated in ER+MC cells and AMPC was observed to improve tamoxifen efficacy in tamoxifen-sensitive cells and to re-sensitize cells to tamoxifen in tamoxifen-resistant ER+MC in vitro and in vivo. Additionally, tamoxifen-resistant ER+MC cells were concomitantly resistant to anthracycline, platinum and fluoropyrimidine drugs, but not to Taxanes. Taxane treatment of tamoxifen-sensitive and resistant ER+MC cells increased TFF3 expression indicating a combination vulnerability for tamoxifen-resistant ER+MC cells. Taxanes increased CSC-like behavior of tamoxifen-sensitive and resistant ER+MC cells which was reduced by AMPC treatment. Taxanes synergized with AMPC to promote apoptosis and reduce CSC-like behavior in vitro and in vivo. Hence, AMPC restored the sensitivity of tamoxifen and enhanced the efficacy of Taxanes in tamoxifen-resistant ER+MC. In conclusion, pharmacological inhibition of TFF3 may serve as an effective combinatorial therapeutic strategy for the treatment of tamoxifen-resistant ER+MC.

Molecularly Targeted Fluorescent Sensors for Visualizing and Tracking Cellular Senescence

Specific identification and monitoring of senescent cells are essential for the in-depth understanding and regulation of senescence-related life processes and diseases. Fluorescent sensors providing real-time and in situ information with spatiotemporal resolution are unparalleled tools and have contributed greatly to this field. This review focuses on the recent progress in fluorescent sensors for molecularly targeted imaging and real-time tracking of cellular senescence. The molecular design, sensing mechanisms, and biological activities of the sensors are discussed. The sensors are categorized by the types of markers and targeting ligands. Accordingly, their molecular recognition and fluorescent performance towards senescence biomarkers are summarized. Finally, the perspective and challenges in this field are discussed, which are expected to assist future design of next-generation sensors for monitoring cellular senescence.

Mitochondrial heterogeneity in diseases

As key organelles involved in cellular metabolism, mitochondria frequently undergo adaptive changes in morphology, components and functions in response to various environmental stresses and cellular demands. Previous studies of mitochondria research have gradually evolved, from focusing on morphological change analysis to systematic multiomics, thereby revealing the mitochondrial variation between cells or within the mitochondrial population within a single cell. The phenomenon of mitochondrial variation features is defined as mitochondrial heterogeneity. Moreover, mitochondrial heterogeneity has been reported to influence a variety of physiological processes, including tissue homeostasis, tissue repair, immunoregulation, and tumor progression. Here, we comprehensively review the mitochondrial heterogeneity in different tissues under pathological states, involving variant features of mitochondrial DNA, RNA, protein and lipid components. Then, the mechanisms that contribute to mitochondrial heterogeneity are also summarized, such as the mutation of the mitochondrial genome and the import of mitochondrial proteins that result in the heterogeneity of mitochondrial DNA and protein components. Additionally, multiple perspectives are investigated to better comprehend the mysteries of mitochondrial heterogeneity between cells. Finally, we summarize the prospective mitochondrial heterogeneity-targeting therapies in terms of alleviating mitochondrial oxidative damage, reducing mitochondrial carbon stress and enhancing mitochondrial biogenesis to relieve various pathological conditions. The possibility of recent technological advances in targeted mitochondrial gene editing is also discussed.

Low-Dose Non-Targeted Effects and Mitochondrial Control

Non-targeted effects (NTE) have been generally regarded as a low-dose ionizing radiation (IR) phenomenon. Recently, regarding long distant abscopal effects have also been observed at high doses of IR) relevant to antitumor radiation therapy. IR is inducing NTE involving intracellular and extracellular signaling, which may lead to short-ranging bystander effects and distant long-ranging extracellular signaling abscopal effects. Internal and "spontaneous" cellular stress is mostly due to metabolic oxidative stress involving mitochondrial energy production (ATP) through oxidative phosphorylation and/or anaerobic pathways accompanied by the leakage of O₂^- and other radicals from mitochondria during normal or increased cellular energy requirements or to mitochondrial dysfunction. Among external stressors, ionizing radiation (IR) has been shown to very rapidly perturb mitochondrial functions, leading to increased energy supply demands and to ROS/NOS production. Depending on the dose, this affects all types of cell constituents, including DNA, RNA, amino acids, proteins, and membranes, perturbing normal inner cell organization and function, and forcing cells to reorganize the intracellular metabolism and the network of organelles. The reorganization implies intracellular cytoplasmic-nuclear shuttling of important proteins, activation of autophagy, and mitophagy, as well as induction of cell cycle arrest, DNA repair, apoptosis, and senescence. It also includes reprogramming of mitochondrial metabolism as well as genetic and epigenetic control of the expression of genes and proteins in order to ensure cell and tissue survival. At low doses of IR, directly irradiated cells may already exert non-targeted effects (NTE) involving the release of molecular mediators, such as radicals, cytokines, DNA fragments, small RNAs, and proteins (sometimes in the form of extracellular vehicles or exosomes), which can induce damage of unirradiated neighboring bystander or distant (abscopal) cells as well as immune responses. Such non-targeted effects (NTE) are contributing to low-dose phenomena, such as hormesis, adaptive responses, low-dose hypersensitivity, and genomic instability, and they are also promoting suppression and/or activation of immune cells. All of these are parts of the main defense systems of cells and tissues, including IR-induced innate and adaptive immune responses. The present review is focused on the prominent role of mitochondria in these processes, which are determinants of cell survival and anti-tumor RT.

Mitochondrial DNA is a target of HBV integration

Hepatitis B virus (HBV) may integrate into the genome of infected cells and contribute to hepatocarcinogenesis. However, the role of HBV integration in hepatocellular carcinoma (HCC) development remains unclear. In this study, we apply a high-throughput HBV integration sequencing approach that allows sensitive identification of HBV integration sites and enumeration of integration clones. We identify 3339 HBV integration sites in paired tumour and non-tumour tissue samples from 7 patients with HCC. We detect 2107 clonally expanded integrations (1817 in tumour and 290 in non-tumour tissues), and a significant enrichment of clonal HBV integrations in mitochondrial DNA (mtDNA) preferentially occurring in the oxidative phosphorylation genes (OXPHOS) and D-loop region. We also find that HBV RNA sequences are imported into the mitochondria of hepatoma cells with the involvement of polynucleotide phosphorylase (PNPASE), and that HBV RNA might have a role in the process of HBV integration into mtDNA. Our results suggest a potential mechanism by which HBV integration may contribute to HCC development.

Porphyromonas gingivalis promotes malignancy and chemo-resistance via GSK3β-mediated mitochondrial oxidative phosphorylation in human esophageal squamous cell carcinoma

Our prior studies have confirmed that long-term colonization of Porphyromonas gingivalis (Pg) and overexpression of the inflammatory factor glycogen synthase kinase 3β (GSK3β) promote the malignant evolution of esophageal squamous cell carcinoma (ESCC). We aimed to investigate the functional mechanism by which Pg could promote ESCC malignancy and chemo-resistance through GSK3β-mediated mitochondrial oxidative phosphorylation (mtOXPHOS), and the clinical implications. The effects of Pg and GSK3β on mtOXPHOS, malignant behaviors and response to paclitaxel and cisplatin treatment of ESCC cells were evaluated by in vitro and in vivo studies. The results showed that Pg induced high expression of the GSK3β protein in ESCC cells and promoted the progression and chemo-resistance via GSK3β-mediated mtOXPHOS in human ESCC. Then, Pg infection and the expression of GSK3β, SIRT1 and MRPS5 in ESCC tissues were detected, and the correlations between each index and postoperative survival of ESCC patients were analysed. The results showed that Pg-positive ESCC patients with high-expression of GSK3β, SIRT1 and MRPS5 have significant short postoperative survival. In conclusion, we demonstrated that the effective removal of Pg and inhibition of its promotion of GSK3β-mediated mtOXPHOS may provide a new strategy for ESCC treatment and new insights into the aetiology of ESCC.

FTO demethylates m6A modifications in CDKAL1 mRNA and promotes gastric cancer chemoresistance by altering mitochondrial dynamics

N6-methyladenosine (m6A) modification is the most common mRNA modification that is considered a new layer of mRNA epigenetic regulation. Demethylase fat mass and obesity-associated protein (FTO) are important in the dynamic regulation of m6A, but their role in gastric cancer (GC) is not fully understood. This study revealed that FTO and CDKAL1 were up-regulated in GC cells and tissue. CDKAL1 is the downstream target of FTO-mediated m6A modification, with FTO promoting GC cell proliferation through CDKAL1 and inducing mitochondrial fusion, eventually causing GC chemoresistance. In conclusion, FTO contributes to the increasing resistance of GC cells to 5-fluorouracil (5-Fu) by upregulating CDKAL1 and inducing mitochondrial fusion.

Tactics with Prebiotics for the Treatment of Metabolic Dysfunction-Associated Fatty Liver Disease via the Improvement of Mitophagy

Mitophagy/autophagy plays a protective role in various forms of liver damage, by renovating cellular metabolism linking to sustain liver homeostasis. A characterized pathway for mitophagy is the phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1)/Parkin-dependent signaling pathway. In particular, PINK1-mediated mitophagy could play an indispensable role in improving the metabolic dysfunction-associated fatty liver disease (MAFLD) which could precede to steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma. In addition, the PI3K/AKT/mTOR pathway might regulate the various characteristics of cellular homeostasis including energy metabolism, cell proliferation, and/or cell protection. Therefore, targeting mitophagy with the alteration of PI3K/AKT/mTOR or PINK1/Parkin-dependent signaling to eliminate impaired mitochondria might be an attractive strategy for the treatment of MAFLD. In particular, the efficacy of prebiotics for the treatment of MAFLD has been suggested to be useful via the modulation of the PI3K/AKT/mTOR/AMPK pathway. Additionally, several edible phytochemicals could activate mitophagy for the improvement of mitochondrial damages, which could also be a promising option to treat MAFLD with providing liver protection. Here, the potential therapeutics with several phytochemicals has been discussed for the treatment of MAFLD. Tactics with a viewpoint of prospective probiotics might contribute to the development of therapeutic interventions.

Unraveling the Peculiar Features of Mitochondrial Metabolism and Dynamics in Prostate Cancer

Prostate cancer (PCa) is the second leading cause of cancer deaths among men in Western countries. Mitochondria, the "powerhouse" of cells, undergo distinctive metabolic and structural dynamics in different types of cancer. PCa cells experience peculiar metabolic changes during their progression from normal epithelial cells to early-stage and, progressively, to late-stage cancer cells. Specifically, healthy cells display a truncated tricarboxylic acid (TCA) cycle and inefficient oxidative phosphorylation (OXPHOS) due to the high accumulation of zinc that impairs the activity of m-aconitase, the enzyme of the TCA cycle responsible for the oxidation of citrate. During the early phase of cancer development, intracellular zinc levels decrease leading to the reactivation of m-aconitase, TCA cycle and OXPHOS. PCa cells change their metabolic features again when progressing to the late stage of cancer. In particular, the Warburg effect was consistently shown to be the main metabolic feature of late-stage PCa cells. However, accumulating evidence sustains that both the TCA cycle and the OXPHOS pathway are still present and active in these cells. The androgen receptor axis as well as mutations in mitochondrial genes involved in metabolic rewiring were shown to play a key role in PCa cell metabolic reprogramming. Mitochondrial structural dynamics, such as biogenesis, fusion/fission and mitophagy, were also observed in PCa cells. In this review, we focus on the mitochondrial metabolic and structural dynamics occurring in PCa during tumor development and progression; their role as effective molecular targets for novel therapeutic strategies in PCa patients is also discussed.

Discovery of Bis-sulfonamides as Novel Inhibitors of Mitochondrial NADH-Quinone Oxidoreductase (Complex I)

Mitochondrial oxidative phosphorylation (OXPHOS) is an essential cellular metabolic process that generates ATP. The enzymes involved in OXPHOS are considered to be promising druggable targets. Through screening of an in-house synthetic library with bovine heart submitochondrial particles, we identified a unique symmetric bis-sulfonamide, KPYC01112 (1) as an inhibitor targeting NADH-quinone oxidoreductase (complex I). Structural modifications of KPYC01112 (1) led to the discovery of the more potent inhibitors 32 and 35 possessing long alkyl chains (IC50 = 0.017 and 0.014 μM, respectively). A photoaffinity labeling experiment using a newly synthesized photoreactive bis-sulfonamide ([125I]-43) revealed that it binds to the 49-kDa, PSST, and ND1 subunits which make up the quinone-accessing cavity of complex I.

Mitochondria-Related Transcriptome Characterization Associated with the Immune Microenvironment, Therapeutic Response and Survival Prediction in Pancreatic Cancer

(1) Background: Pancreatic cancer (PC) is one of the most lethal tumors. Mitochondrial dysfunction has been reported to be involved in cancer development; however, its role in PC has remained unclear. (2) Methods: The differentially expressed NMGs were selected between PC and normal pancreatic tissue. The NMG-related prognostic signature was established by LASSO regression. A nomogram was developed based on the 12-gene signature combined with other significant pathological features. An extensive analysis of the 12 critical NMGs was performed in multiple dimensions. The expression of some key genes was verified in our external cohort. (3) Results: Mitochondria-related transcriptome features was obviously altered in PC compared with normal pancreas tissue. The 12-NMG signature showed good performance in predicting prognosis in various cohorts. The high- and low-risk groups exhibited notable diversity in gene mutation characteristics, biological characteristics, chemotherapy response, and the tumor immune microenvironment. Critical gene expression was demonstrated in our cohort at the mRNA and protein levels and in organelle localization. (4) Conclusions: Our study analyzed the mitochondrial molecular characterization of PC, proving the crucial role of NMGs in PC development. The established NMG signature helps classify patient subtypes in terms of prognosis prediction, treatment response, immunological features, and biological function, providing a potential therapeutic strategy targeting mitochondrial transcriptome characterization.

Reprogramming of glycolysis by chemical carcinogens during tumor development

Indiscriminate usage and mismanagement of chemicals in the agricultural and industrial sectors have contaminated different environmental compartments. Exposure to these persistent and hazardous pollutants like heavy metals, endocrine disruptors, aromatic hydrocarbons, and pesticides can result in various health adversities, including cancer. Chemical carcinogens follow a similar pattern of carcinogenesis, like oxidative stress, chromosomal aberration, DNA double-strand break, mismatch repair, and misregulation of oncogenic and/or tumor suppressors. Out of several cancer-associated endpoints, cellular metabolic homeostasis is the commonest to be deregulated upon chemical exposure. Chemical carcinogens hamper glycolytic reprogramming to fuel the malignant transformation of the cells and/or promote cancer progression. Several regulators like Akt, ERK, Ras, c-Myc, HIF-1α, and p53 regulate glycolysis in chemical-induced carcinogenesis. However, the deregulation of the anabolic biochemistry of glucose during chemical-induced carcinogenesis remains to be uncovered. This review comprehensively covers the environmental chemical-induced glycolytic shift during carcinogenesis and its mechanism. The focus is also to fill the major gaps associated with understanding the fairy tale between environmental carcinogens and metabolic reprogramming. Although evidence from studies regarding glycolytic reprogramming in chemical carcinogenesis provides valuable insights into cancer therapy, exposure to a mixture of toxicants and their mechanism of inducing carcinogenesis still needs to be studied.

Potential Diets to Improve Mitochondrial Activity in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, the pathogenesis of which is based on alternations in the mitochondria of motor neurons, causing their progressive death. A growing body of evidence shows that more efficient mitophagy could prevent and/or treat this disorder by suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. Mitophagy has been considered one of the main mechanisms responsible for mitochondrial quality control. Since ALS is characterized by enormous oxidative stress, several edible phytochemicals that can activate mitophagy to remove damaged mitochondria could be considered a promising option to treat ALS by providing neuroprotection. Therefore, it is of great significance to explore the mechanisms of mitophagy in ALS and to understand the effects and/or molecular mechanisms of phytochemical action, which could translate into a treatment for neurodegenerative diseases, including ALS.

Targeting Mitochondrial Metabolism to Reverse Radioresistance: An Alternative to Glucose Metabolism

Radiotherapy failure and poor tumor prognosis are primarily attributed to radioresistance. Improving the curative effect of radiotherapy and delaying cancer progression have become difficult problems for clinicians. Glucose metabolism has long been regarded as the main metabolic process by which tumor cells meet their bioenergetic and anabolic needs, with the complex interactions between the mitochondria and tumors being ignored. This misconception was not dispelled until the early 2000s; however, the cellular molecules and signaling pathways involved in radioresistance remain incompletely defined. In addition to being a key metabolic site that regulates tumorigenesis, mitochondria can influence the radiation effects of malignancies by controlling redox reactions, participating in oxidative phosphorylation, producing oncometabolites, and triggering apoptosis. Therefore, the mitochondria are promising targets for the development of novel anticancer drugs. In this review, we summarize the internal relationship and related mechanisms between mitochondrial metabolism and cancer radioresistance, thus exploring the possibility of targeting mitochondrial signaling pathways to reverse radiation insensitivity. We suggest that attention should be paid to the potential value of mitochondria in prolonging the survival of cancer patients.

Anisomycin inhibits angiogenesis, growth, and survival of triple-negative breast cancer through mitochondrial dysfunction, AMPK activation, and mTOR inhibition

Aberrant upregulation of mitochondrial biogenesis is observed in breast cancer and holds potential therapeutic option. In our work, we showed that inhibition of mitochondrial function by anisomycin is effective against triple-negative breast cancer (TNBC). Anisomycin inhibits growth and induces caspase-dependent apoptosis in a panel of TNBC cell lines. Of note, anisomycin at a tolerable dose remarkably suppresses growth of TNBC in mice. In addition, anisomycin effectively targets breast cancer angiogenesis through inhibiting capillary network formation, migration, proliferation, and survival. Mechanistic studies show that although anisomycin activates p38 and JNK, their activations are not required for anisomycin's action. In contrast, anisomycin inhibits mitochondrial respiration, and decreases mitochondrial membrane potential and adenosine triphosphate (ATP) level. The inhibitory effect of anisomycin is significantly reversed in mitochondria respiration-deficient ρ0 cells. As a consequence, anisomycin activates AMPK and inhibits mammalian target-of-rapamycin signaling pathways. Our work demonstrated that anisomycin is a useful addition to the treatment armamentarium for TNBC.

Mitochondrial Genetic and Epigenetic Regulations in Cancer: Therapeutic Potential

Mitochondria are dynamic organelles managing crucial processes of cellular metabolism and bioenergetics. Enabling rapid cellular adaptation to altered endogenous and exogenous environments, mitochondria play an important role in many pathophysiological states, including cancer. Being under the control of mitochondrial and nuclear DNA (mtDNA and nDNA), mitochondria adjust their activity and biogenesis to cell demands. In cancer, numerous mutations in mtDNA have been detected, which do not inactivate mitochondrial functions but rather alter energy metabolism to support cancer cell growth. Increasing evidence suggests that mtDNA mutations, mtDNA epigenetics and miRNA regulations dynamically modify signalling pathways in an altered microenvironment, resulting in cancer initiation and progression and aberrant therapy response. In this review, we discuss mitochondria as organelles importantly involved in tumorigenesis and anti-cancer therapy response. Tumour treatment unresponsiveness still represents a serious drawback in current drug therapies. Therefore, studying aspects related to genetic and epigenetic control of mitochondria can open a new field for understanding cancer therapy response. The urgency of finding new therapeutic regimens with better treatment outcomes underlines the targeting of mitochondria as a suitable candidate with new therapeutic potential. Understanding the role of mitochondria and their regulation in cancer development, progression and treatment is essential for the development of new safe and effective mitochondria-based therapeutic regimens.

Protection Against Drug-Induced Liver Injuries Through Nutraceuticals via Amelioration of Nrf-2 Signaling

Hepatotoxicity caused by the overdose of various medications is a leading cause of drug-induced liver injury. Overdose of drugs causes hepatocellular necrosis. Nutraceuticals are reported to prevent drug-induced liver failure. The present article aims to review the protection provided by various medicinal plants against hepatotoxic drugs. Ayurveda is considered a conventional restorative arrangement in India. It is consistently used for ages and is still used today to cure drug-induced hepatotoxicity by focusing on antioxidant stress response pathways such as the nuclear factor erythroid-2 (Nrf-2) antioxidant response element signaling pathway. Nrf-2 is a key transcription factor that entangles Kelch-like ECH-associating protein 1, a protein found in the cell cytoplasm. Some antioxidant enzymes, such as gamma glycine cysteine ligase (γ-GCL) and heme oxygenase-1 (HO-1), are expressed in Nrf-2 targeted genes. Their expression, in turn, decreases the stimulation of hepatic macrophages and induces the messenger RNA (mRNA) articulation of proinflammatory factors including tumor necrosis factor α. This review will cover various medicinal plants from a mechanistic view and how they stimulate and interact with Nrf-2, the master regulator of the antioxidant response to counterbalance oxidative stress. Interestingly, therapeutic plants have become popular in the medical sector due to safer yet effective supplementation for the prevention and treatment of new human diseases. The contemporary study is expected to collect information on a variety of therapeutic traditional herbs that have been studied in the context of drug-induced liver toxicity, as nutraceuticals are the most effective treatments for oxidative stress-induced hepatotoxicity. They are less genotoxic, have a lower cost, and are readily available. Together, nutraceuticals exert protective effects against drug-induced hepatotoxicity through the inhibition of oxidative stress, inflammation, and apoptosis. Its mechanism(s) are considered to be associated with the γ-GCL/HO-1 and Nrf-2 signaling pathways. KEY TEACHING POINTSThe liver is the most significant vital organ that carries out metabolic activities of the body such as the synthesis of glycogen, the formation of triglycerides and cholesterol, as well as the formation of bile.Acute liver failure is caused by the consumption of certain drugs; drug-induced liver injury is the major condition.The chemopreventive activity of nutraceuticals may be related to oxidative stress reduction and attenuation of biosynthetic processes involved in hepatic injury via amelioration of the nuclear factor erythroid-2 (Nrf-2) signaling pathway.Nrf-2 is a key transcription factor that is found in the cell cytoplasm resulting in the expression of various genes such as gamma glycine cysteine ligase and heme oxygenase-1.Nutraceutical-rich phytochemicals possess high antioxidant activity, which helps in the prevention of hepatic injury.

The multifaceted roles of mitochondria at the crossroads of cell life and death in cancer

Mitochondria are the cytoplasmic organelles mostly known as the "electric engine" of the cells; however, they also play pivotal roles in different biological processes, such as cell growth/apoptosis, Ca²⁺ and redox homeostasis, and cell stemness. In cancer cells, mitochondria undergo peculiar functional and structural dynamics involved in the survival/death fate of the cell. Cancer cells use glycolysis to support macromolecular biosynthesis and energy production ("Warburg effect"); however, mitochondrial OXPHOS has been shown to be still active during carcinogenesis and even exacerbated in drug-resistant and stem cancer cells. This metabolic rewiring is associated with mutations in genes encoding mitochondrial metabolic enzymes ("oncometabolites"), alterations of ROS production and redox biology, and a fine-tuned balance between anti-/proapoptotic proteins. In cancer cells, mitochondria also experience dynamic alterations from the structural point of view undergoing coordinated cycles of biogenesis, fusion/fission and mitophagy, and physically communicating with the endoplasmic reticulum (ER), through the Ca²⁺ flux, at the MAM (mitochondria-associated membranes) levels. This review addresses the peculiar mitochondrial metabolic and structural dynamics occurring in cancer cells and their role in coordinating the balance between cell survival and death. The role of mitochondrial dynamics as effective biomarkers of tumor progression and promising targets for anticancer strategies is also discussed.

Pathogenic mitochondrial dysfunction and metabolic abnormalities

Herein we trace links between biochemical pathways, pathogenesis, and metabolic diseases to set the stage for new therapeutic advances. Cellular and acellular microorganisms including bacteria and viruses are primary pathogenic drivers that cause disease. Missing from this statement are subcellular compartments, importantly mitochondria, which can be pathogenic by themselves, also serving as key metabolic disease intermediaries. The breakdown of food molecules provides chemical energy to power cellular processes, with mitochondria as powerhouses and ATP as the principal energy carrying molecule. Most animal cell ATP is produced by mitochondrial synthase; its central role in metabolism has been known for >80 years. Metabolic disorders involving many organ systems are prevalent in all age groups. Progressive pathogenic mitochondrial dysfunction is a hallmark of genetic mitochondrial diseases, the most common phenotypic expression of inherited metabolic disorders. Confluent genetic, metabolic, and mitochondrial axes surface in diabetes, heart failure, neurodegenerative disease, and even in the ongoing coronavirus pandemic.

Mitochondrially localized MPZL3 emerges as a signaling hub of mammalian physiology

MPZL3 is a nuclear-encoded, mitochondrially localized, immunoglobulin-like V-type protein that functions as a key regulator of epithelial cell differentiation, lipid metabolism, ROS production, glycemic control, and energy expenditure. Recently, MPZL3 has surfaced as an important modulator of sebaceous gland function and of hair follicle cycling, an organ transformation process that is also governed by peripheral clock gene activity and PPARγ. Given the phenotype similarities and differences between Mpzl3 and Pparγ knockout mice, we propose that MPZL3 serves as a signaling hub that is regulated by core clock gene products and/or PPARγ to translate signals from these nuclear transcription factors to the mitochondria to modulate circadian and metabolic regulation. Conservation between murine and human MPZL3 suggests that human MPZL3 may have similarly complex functions in health and disease. We summarize current knowledge and discuss future directions to elucidate the full spectrum of MPZL3 functions in mammalian physiology.

Phytochemicals: Targeting Mitophagy to Treat Metabolic Disorders

Metabolic disorders include metabolic syndrome, obesity, type 2 diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular diseases. Due to unhealthy lifestyles such as high-calorie diet, sedentary and physical inactivity, the prevalence of metabolic disorders poses a huge challenge to global human health, which is the leading cause of global human death. Mitochondrion is the major site of adenosine triphosphate synthesis, fatty acid β-oxidation and ROS production. Accumulating evidence suggests that mitochondrial dysfunction-related oxidative stress and inflammation is involved in the development of metabolic disorders. Mitophagy, a catabolic process, selectively degrades damaged or superfluous mitochondria to reverse mitochondrial dysfunction and preserve mitochondrial function. It is considered to be one of the major mechanisms responsible for mitochondrial quality control. Growing evidence shows that mitophagy can prevent and treat metabolic disorders through suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. In the past decade, in order to expand the range of pharmaceutical options, more and more phytochemicals have been proven to have therapeutic effects on metabolic disorders. Many of these phytochemicals have been proved to activate mitophagy to ameliorate metabolic disorders. Given the ongoing epidemic of metabolic disorders, it is of great significance to explore the contribution and underlying mechanisms of mitophagy in metabolic disorders, and to understand the effects and molecular mechanisms of phytochemicals on the treatment of metabolic disorders. Here, we investigate the mechanism of mitochondrial dysfunction in metabolic disorders and discuss the potential of targeting mitophagy with phytochemicals for the treatment of metabolic disorders, with a view to providing a direction for finding phytochemicals that target mitophagy to prevent or treat metabolic disorders.

Mitochondrial nanomedicine: Subcellular organelle-specific delivery of molecular medicines

As mitochondria network together to act as the master sensors and effectors of apoptosis, ATP production, reactive oxygen species management, mitophagy/autophagy, and homeostasis; this organelle is an ideal target for pharmaceutical manipulation. Mitochondrial dysfunction contributes to many diseases, for example, β-amyloid has been shown to interfere with mitochondrial protein import and induce apoptosis in Alzheimer's Disease while some forms of Parkinson's Disease are associated with dysfunctional mitochondrial PINK1 and Parkin proteins. Mitochondrial medicine has applications in the treatment of an array of pathologies from cancer to cardiovascular disease. A challenge of mitochondrial medicine is directing therapies to a subcellular target. Nanotechnology based approaches combined with mitochondrial targeting strategies can greatly improve the clinical translation and effectiveness of mitochondrial medicine. This review discusses mitochondrial drug delivery approaches and applications of mitochondrial nanomedicines. Nanomedicine approaches have the potential to drive the success of mitochondrial therapies into the clinic.

Conjugation of Natural Triterpenic Acids with Delocalized Lipophilic Cations: Selective Targeting Cancer Cell Mitochondria

Currently, a new line of research on mitochondria-targeted anticancer drugs is actively developing in the field of biomedicine and medicinal chemistry. The distinguishing features of this universal target for anticancer agents include presence of mitochondria in the overwhelming majority, if not all types of transformed cells, crucial importance of these cytoplasmic organelles in energy production, regulation of cell death pathways, as well as generation of reactive oxygen species and maintenance of calcium homeostasis. Hence, mitochondriotropic anticancer mitocan agents, acting through mitochondrial destabilization, have good prospects in cancer therapy. Available natural pentacyclic triterpenoids are considered promising scaffolds for development of new mitochondria-targeted anticancer agents. These secondary metabolites affect the mitochondria of tumor cells and initiate formation of reactive oxygen species. The present paper focuses on the latest research outcomes of synthesis and study of cytotoxic activity of conjugates of pentacyclic triterpenoids with some mitochondria-targeted cationic lipophilic molecules and highlights the advantages of applying them as novel mitocan agents compared to their prototype natural triterpenic acids.