TOM40 Inhibits Ovarian Cancer Cell Growth by Modulating Mitochondrial Function Including Intracellular ATP and ROS Levels

Development and validation of a kinase-related gene signature as a novel diagnostic and prognostic model for prostate cancer

BACKGROUND

Prostate cancer (PCa) is a prevalent malignant tumor in men worldwide. Kinases play a key role in the development of multiple tumors. Nevertheless, the role of kinases in PCa remains largely unclear.

METHODS

A kinase-related gene signature was constructed by LASSO Cox regression analysis using the TCGA_PRAD cohort. The diagnostic and prognostic values of the signature were then evaulated. Furthermore, a loss-of-function assay was carried out to explore the function of NEK5 in PCa.

RESULTS

A signature of 13 kinase-related genes (NEK5, FRK, STK39, STYK1, IGF1R, RPS6KC1, TTK, CDK1, NEK2, PTK6, DAPK1, MELK and EPHA10) was constructed. The PCa patients presenting a high-risk score according to the signature demonstrated poorer disease-free survival compared to those with a low score. Additionally, TMB was found to be remarkably increased in patients categorized as high-risk relative to low-risk patients. Moreover, the 13-gene signature may also have good predictive value for PCa diagnosis. Furthermore, NEK5 expression was remarkably elevated in PCa tissues relative to benign tissues. NEK5 deficiency significantly inhibited PCa cell growth and suppressed mitochondrial OXPHOS.

CONCLUSION

The 13-gene signature constructed in this study may exhibit good performance in PCa diagnosis and prognosis evaluation. We identified the oncogenic role of NEK5 in PCa. NEK5 may serve as a therapeutic target for treatting PCa.

Exploring the mechanism of action of succinic acid in ovarian cancer via single-cell sequencing of the tumor immune microenvironment

Background

The main treatments for ovarian cancer are surgery, chemotherapy, radiotherapy, and targeted therapy. Targeted therapy is a new treatment method that has emerged in recent years and relies on specific molecular targets to treat cancer. Succinic acid is a key intermediate product in the tricarboxylic acid cycle. Research has shown that succinic acid has antioxidant properties and can alleviate oxidative stress in cells and tissues. These findings indicate the potential application of succinic acid in antioxidant therapy and the prevention of oxidative damage. This study explored the potential targets and therapeutic mechanisms of succinic acid in ovarian cancer.

Methods

Using bioinformatics and single-cell sequencing technology, the hub genes related to succinic acid and ovarian cancer and the frequency and gene expression patterns of different cell types in ovarian cancer patients and normal individuals were analyzed.

Results

The frequency of immune cells, including B cells, CD4+ cells, CD8+ cells, macrophages, and plasma cells, was significantly increased in ovarian cancer patients, and the frequency of other cell types, such as endothelial cells, NK cells, and pericytes/SMCs, was decreased. Further research revealed three key hub genes: SPP1, SLPI, and CD9. The expression patterns of these genes in ovarian cancer were closely related to different cell types. SPP1 was expressed mainly in macrophages, SLPI was expressed in epithelial cells, and CD9 was expressed in pericytes/SMCs and epithelial cells. SPP1, SLPI, and CD9 and their mechanisms of action may be potential targets for the treatment of ovarian cancer with succinic acid.

Conclusions

This study investigated the potential therapeutic targets and mechanisms of succinic acid in ovarian cancer and the differences in immune cell infiltration and gene expression patterns, providing important insights for future tumor immunotherapy research.

Review of electrophysiological models to study membrane potential changes in breast cancer cell transformation and tumor progression

The transformation of normal breast cells into cancerous cells is a complex process influenced by both genetic and microenvironmental factors. Recent studies highlight the significant role of membrane potential (Vm) alterations in this transformation. Cancer cells typically exhibit a depolarized resting membrane potential (RMP) compared to normal cells, which correlates with increased cellular activity and more aggressive cancer behavior. These RMP and Vm changes are associated with altered ion channel activity, altered calcium dynamics, mitochondrial dysfunction, modified gap junction communication, and disrupted signaling pathways. Such fluctuations in RMP and Vm influence key processes in cancer progression, including cell proliferation, migration, and invasion. Notably, more aggressive subtypes of breast cancer cells display more frequent and pronounced Vm fluctuations. Understanding the electrical properties of cancer cells provides new insights into their behavior and offers potential therapeutic targets, such as ion channels and Vm regulation. This review synthesizes current research on how various factors modulate membrane potential and proposes an electrophysiological model of breast cancer cells based on experimental and clinical data from the literature. These findings may pave the way for novel pharmacological targets for clinicians, researchers, and pharmacologists in treating breast cancer.

TOM40 as a prognostic oncogene for oral squamous cell carcinoma prognosis

BACKGROUND

To investigate the role of the translocase of the outer mitochondrial membrane 40 (TOM40) in oral squamous cell carcinoma (OSCC) with the aim of identifying new biomarkers or potential therapeutic targets.

METHODS

TOM40 expression level in OSCC was evaluated using datasets downloaded from The Cancer Genome Atlas (TCGA), as well as clinical data. The correlation between TOM40 expression level and the clinicopathological parameters and survival were analyzed in TCGA. The signaling pathways associated with TOM40 were identified through gene set enrichment analysis. A network of genes co-expressed with TOM40 was constructed and functionally annotated by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The immune infiltration pattern in OSCC was analyzed in the TCGA-OSCC cohort using the CIBERSORT algorithm. Clinically significant factors of OSCC were screened through the expression levels of TOM40 and a clinically relevant nomogram was constructed. The TCGA-OSCC cohort was divided into the TOM40high and TOM40low groups and the correlation between TOM40 expression level and the sensitivity to frequently used chemotherapeutic drugs was evaluated. CCK-8 and colony formation assays were applied to determine the cell growth.

RESULTS

TOM40 was highly expressed in OSCC tissues and correlated negatively with the overall survival (P < 0.05). Patients with high TOM40 expression level showed worse prognosis. Furthermore, GO and KEGG enrichment analyses of the differentially expressed genes related to TOM40 showed that these genes are mainly associated with immunity and tumorigenesis. Immunological infiltration analysis has found that the expression levels of TOM40 are correlated with the proportions of several immune cells. Moreover, we found that TOM40 knockdown inhibited cell growth in OSCC cell lines.

CONCLUSIONS

Our results uncovered that TOM40 is a reliable prognostic marker and therapeutic target in OSCC.

Chrysoeriol: a natural RANKL inhibitor targeting osteoclastogenesis and ROS regulation for osteoporosis therapy

Chrysoeriol (CHE) is a naturally occurring compound with established anti-inflammatory and anti-tumor effects. This study examines its potential role in regulating osteoclast differentiation and activity, both of which are crucial for bone remodeling. Computational docking revealed high binding affinity between CHE and RANKL, specifically at the Lys-181 residue of RANKL, suggesting potential inhibitory interactions on osteoclastogenesis. In vitro assays confirmed CHE's non-toxic profile at concentrations below 20 μM and demonstrated a dose-dependent suppression of osteoclast differentiation. Notably, CHE treatment significantly reduced TRAP activity and bone resorption capacity in a dose-dependent manner. Furthermore, CHE markedly decreased ROS production by NOX-1 expression and modulated the NRF2/KEAP1 pathway to enhance ROS clearance. The compound also showed inhibitory effects on the NF-κB and MAPK signaling pathways, which are crucial for osteoclast activation. In an ovariectomized mouse model, administration of CHE mitigated bone loss, indicating its therapeutic potential in osteoporosis. Collectively, these findings establish CHE as a promising natural therapeutic agent for treating bone disorders characterized by excessive bone resorption, underscoring the need for further clinical investigation.

TOMM40 Correlates with Cholesterol and is Predictive of a Favorable Prognosis in Endometrial Carcinoma

BACKGROUND

A link between cholesterol and endometrial cancer has been established, but current studies have been limited in their findings. We aimed to elucidate the causal relationship between cholesterol and endometrial cancer and to find prognostic genes for endometrial cancer.

METHODS

We first explored the causal relationship between total cholesterol and endometrial cancer using two-sample Mendelian randomization and then obtained differential genes to screen for prognosis-related genes in endometrial cancer. Then, we utilized pan-cancer analysis based on RNA sequencing data to evaluate the expression pattern and immunological role of the Translocase of Outer Mitochondrial Membrane 40 (TOMM40). Through multiple transcriptome datasets and multi-omics in-depth analysis, we comprehensively explore the relationship of TOMM40 expression with clinicopathologic characteristics, clinical outcomes and mutations in endometrial cancer. Lastly, we systematically associated the TOMM40 with different cancers from immunological properties from numerous perspectives, such as immune cell infiltration, immune checkpoint inhibitors, immunotherapy, gene mutation load and microsatellite instability.

RESULTS

We found a negative association between cholesterol and endometrial cancer. A total of 78 genes were enriched by relevant single nucleotide polymorphisms (SNPs), of which 12 upregulated genes and 5 downregulated genes in endometrial cancer. TOMM40 was found to be a prognostic gene associated with endometrial cancer by prognostic analysis. TOMM40 was found to be positively correlated with the infiltration of most immune cells and immunization checkpoints in a subsequent study. Meanwhile, TOMM40 also was an oncogene in many cancer types. High TOMM40 was associated with lower genome stability.

CONCLUSION

The findings of our study indicate that the maintenance of normal total cholesterol metabolism is associated with a decreased risk of developing endometrial cancer. Moreover, TOMM40 may have potential as a prognostic indicator for endometrial cancer.

TOMM40 regulates hepatocellular and plasma lipid metabolism via an LXR-dependent pathway

OBJECTIVE

The gene encoding TOMM40 (Transporter of Outer Mitochondrial Membrane 40) is adjacent to that encoding APOE, which has a central role in lipid and lipoprotein metabolism. While human genetic variants near APOE and TOMM40 have been shown to be strongly associated with plasma lipid levels, a specific role for TOMM40 in lipid metabolism has not been established, and the present study was aimed at assessing this possibility.

METHODS

TOMM40 was knocked down by siRNA in human hepatoma HepG2 cells, and effects on mitochondrial function, lipid phenotypes, and crosstalk between mitochondria, ER, and lipid droplets were examined. Additionally, hepatic and plasma lipid levels were measured in mice following shRNA-induced knockdown of Tomm40 shRNA.

RESULTS

In HepG2 cells, TOMM40 knockdown upregulated expression of APOE and LDLR in part via activation of LXRB (NR1H2) by oxysterols, with consequent increased uptake of VLDL and LDL. This is in part due to disruption of mitochondria-endoplasmic reticulum contact sites, with resulting accrual of reactive oxygen species and non-enzymatically derived oxysterols. With TOMM40 knockdown, cellular triglyceride and lipid droplet content were increased, effects attributable in part to receptor-mediated VLDL uptake, since lipid staining was significantly reduced by concomitant suppression of either LDLR or APOE. In contrast, cellular cholesterol content was reduced due to LXRB-mediated upregulation of the ABCA1 transporter as well as increased production and secretion of oxysterol-derived cholic acid. Consistent with the findings in hepatoma cells, in vivo knockdown of TOMM40 in mice resulted in significant reductions of plasma triglyceride and cholesterol concentrations, reduced hepatic cholesterol and increased triglyceride content, and accumulation of lipid droplets leading to development of steatosis.

CONCLUSIONS

These findings demonstrate a role for TOMM40 in regulating hepatic lipid and plasma lipoprotein levels and identify mechanisms linking mitochondrial function with lipid metabolism.

Ferroptosis and myocardial ischemia-reperfusion: mechanistic insights and new therapeutic perspectives

Myocardial ischemia-reperfusion injury (MIRI) is a significant factor in the development of cardiac dysfunction following a myocardial infarction. Ferroptosis, a type of regulated cell death driven by iron and marked by lipid peroxidation, has garnered growing interest for its crucial involvement in the pathogenesis of MIRI.This review comprehensively examines the mechanisms of ferroptosis, focusing on its regulation through iron metabolism, lipid peroxidation, VDAC signaling, and antioxidant system dysregulation. We also compare ferroptosis with other forms of cell death to highlight its distinct characteristics. Furthermore, the involvement of ferroptosis in MIRI is examined with a focus on recent discoveries concerning ROS generation, mitochondrial impairment, autophagic processes, ER stress, and non-coding RNA regulation. Lastly, emerging therapeutic strategies that inhibit ferroptosis to mitigate MIRI are reviewed, providing new insights into potential clinical applications.

Pan-Cancer Analysis of the Prognostic and Immunological Role of TOMM40 to Identify Its Function in Breast Cancer

Breast cancer (BRCA) is currently the most commonly diagnosed malignancy in women worldwide. Previous studies have demonstrated that mitophagy is important for the prevention and treatment of BRCA. However, few studies have focused on the individual mitochondrial autophagy-related genes (MARG) in human cancers. Based on bioinformatics analyses, TOMM40 was identified as a prognostic DEMARG (PDEMARGs); Kaplan-Meier (KM) survival analysis also indicates that TOMM40 can be useful as a prognostic indicator in BRCAs, with patients in the high expression group having a poorer prognosis. For 20 distinct cancer kinds, there were appreciable differences in the expression of TOMM40 between tumor and normal tissues; in addition, in 21 different cancer types, there were associations between the expression profile of TOMM40 and patient prognosis. Gene Set Enrichment Analysis (GSEA), functional enrichment analysis, and immunological and drug sensitivity analyses of TOMM40 have indicated its biological significance in pan-cancers. Knockdown of TOMM40 in MDA-MB-231 cells inhibited their proliferation, migration, and invasiveness. In conclusion, we found that TOMM40 has prognostic value in 21 cancers, including breast cancer, by bioinformatics analysis. Based on immune correlation analysis, TOMM40 may also be a potential immunotherapeutic target for the treatment of BRCA. Therefore, our results may provide researchers to further explore the role of MARGs, especially TOMM40, in the developmental process of breast cancer, which may provide new directions and targets for the improvement of prognosis of breast cancer patients and their treatment.

TOM40 mediates the effect of TSPO on postpartum depression partially through regulating calcium homeostasis in microglia

AIMS

To assess the effect of the translocator protein 18 kDa (TSPO) on postpartum depression and explore its mechanism.

METHODS

Postpartum depression (PPD) mouse model was established, and flow cytometry, immunofluorescence, Western blot analysis, real-time quantitative PCR, adeno-associated virus (AAV), co-immunoprecipitation-mass spectrometry and immunofluorescence co-staining were used to detect the effect of TSPO ligand ZBD-2 on PPD mice.

RESULTS

ZBD-2 inhibits the overactivation of microglia in the hippocampus and amygdala of PPD model mice. ZBD-2 not only inhibited the inflammation but also repressed the burst of reactive oxygen species (ROS) and mitochondrial ROS (mtROS). Meanwhile, ZBD-2 protects mitochondria from LPS-induced damages through inhibiting the influx of calcium. ZBD-2 modulated the calcium influx by increasing the level of translocase of the outer mitochondrial membrane 40 (TOM40) and reducing the interaction of TSPO and TOM40. In addition, the effect of ZBD-2 was partially dependent on anti-oxidative process. Knockdown of TOM40 by adeno-associated virus (AAV) in the hippocampus or amygdala dramatically reduced the effect of ZBD-2 on PPD, indicating that TOM40 mediates the effect of ZBD-2 on PPD.

CONCLUSIONS

TOM40 is required for the effect of ZBD-2 on treating anxiety and depression in PPD mice. This study reveals the role of microglia TSPO in PPD development and provides the new therapeutic strategy for PPD.

Mitochondrial Translocase TOMM22 Is Overexpressed in Pancreatic Cancer and Promotes Aggressive Growth by Modulating Mitochondrial Protein Import and Function

Pancreatic cancer has the worst prognosis among all cancers, underscoring the need for improved management strategies. Dysregulated mitochondrial function is a common feature in several malignancies, including pancreatic cancer. Although mitochondria have their own genome, most mitochondrial proteins are nuclear-encoded and imported by a multi-subunit translocase of the outer mitochondrial membrane (TOMM). TOMM22 is the central receptor of the TOMM complex and plays a role in complex assembly. Pathobiologic roles of TOMM subunits remain largely unexplored. Here we report that TOMM22 protein/mRNA is overexpressed in pancreatic cancer and inversely correlated with disease outcomes. TOMM22 silencing decreased, while its forced overexpression promoted the growth and malignant potential of the pancreatic cancer cells. Increased import of several mitochondrial proteins, including those associated with mitochondrial respiration, was observed upon TOMM22 overexpression which was associated with increased RCI activity, NAD+/NADH ratio, oxygen consumption rate, membrane potential, and ATP production. Inhibition of RCI activity decreased ATP levels and suppressed pancreatic cancer cell growth and malignant behavior confirming that increased TOMM22 expression mediated the phenotypic changes via its modulation of mitochondrial protein import and functions. Altogether, these results suggest that TOMM22 overexpression plays a significant role in pancreatic cancer pathobiology by altering mitochondrial protein import and functions.

IMPLICATIONS

TOMM22 bears potential for early diagnostic/prognostic biomarker development and therapeutic targeting for better management of patients with pancreatic cancer.

Arginine-methylated c-Myc affects mitochondrial mitophagy in mouse acute kidney injury via Slc25a24

The transcription factor methylated c-Myc heterodimerizes with MAX to modulate gene expression, and plays an important role in energy metabolism in kidney injury but the exact mechanism remains unclear. Mitochondrial solute transporter Slc25a24 imports ATP into mitochondria and is central to energy metabolism. Gene Expression Omnibus data analysis reveals Slc25a24 and c-Myc are consistently upregulated in all the acute kidney injury (AKI) cells. Pearson correlation analysis also shows that Slc25a24 and c-Myc are strongly correlated (⍴ > 0.9). Mutant arginine methylated c-Myc (R299A and R346A) reduced its combination with MAX when compared with the wild type of c-Myc. On the other hand, the Slc25a24 levels were also correspondingly reduced, which induced the downregulation of ATP production. The results promoted reactive oxygen species (ROS) production and mitophagy generation. The study revealed that the c-Myc overexpression manifested the most pronounced mitochondrial DNA depletion. Additionally, the varied levels of mitochondrial proteins like TIM23, TOM20, and PINK1 in each group, particularly the elevated levels of PINK1 in AKI model groups and lower levels of TIM23 and TOM20 in the c-Myc overexpression group, suggest potential disruptions in mitochondrial dynamics and homeostasis, indicating enhanced mitophagy or mitochondrial loss. Therefore, arginine-methylated c-Myc affects mouse kidney injury by regulating mitochondrial ATP and ROS, and mitophagy via Slc25a24.

TOMM40 and TOMM22 of the Translocase Outer Mitochondrial Membrane Complex rescue statin-impaired mitochondrial dynamics, morphology, and mitophagy in skeletal myotubes

Background

Statins are the drugs most commonly used for lowering plasma low-density lipoprotein (LDL) cholesterol levels and reducing cardiovascular disease risk. Although generally well tolerated, statins can induce myopathy, a major cause of non-adherence to treatment. Impaired mitochondrial function has been implicated as a cause of statin-induced myopathy, but the underlying mechanism remains unclear. We have shown that simvastatin downregulates transcription of TOMM40 and TOMM22 , genes that encode major subunits of the translocase of outer mitochondrial membrane (TOM) complex which is responsible for importing nuclear-encoded proteins and maintaining mitochondrial function. We therefore investigated the role of TOMM40 and TOMM22 in mediating statin effects on mitochondrial function, dynamics, and mitophagy.

Methods

Cellular and biochemical assays and transmission electron microscopy were used to investigate effects of simvastatin and TOMM40 and TOMM22 expression on measures of mitochondrial function and dynamics in C2C12 and primary human skeletal cell myotubes.

Results

Knockdown of TOMM40 and TOMM22 in skeletal cell myotubes impaired mitochondrial oxidative function, increased production of mitochondrial superoxide, reduced mitochondrial cholesterol and CoQ levels, disrupted mitochondrial dynamics and morphology, and increased mitophagy, with similar effects resulting from simvastatin treatment. Overexpression of TOMM40 and TOMM22 in simvastatin-treated muscle cells rescued statin effects on mitochondrial dynamics, but not on mitochondrial function or cholesterol and CoQ levels. Moreover, overexpression of these genes resulted in an increase in number and density of cellular mitochondria.

Conclusion

These results confirm that TOMM40 and TOMM22 are central in regulating mitochondrial homeostasis and demonstrate that downregulation of these genes by statin treatment mediates disruption of mitochondrial dynamics, morphology, and mitophagy, effects that may contribute to statin-induced myopathy.

GRAPHICAL ABSTRACT

TOM40 regulates the progression of nasopharyngeal carcinoma through ROS-mediated AKT/mTOR and p53 signaling

Nasopharyngeal carcinoma (NPC) is a prevalent cancer in Southern China, North Africa, and Southeast Asia. The translocase of the outer membrane (TOM) 40 is a transporter of mitochondrial proteins, and is involved in ovarian cancer cell growth. However, its role in the progression of NPC is still unclear. We found that TOM40 levels were upregulated in NPC tissues and multiple NPC cell lines. In addition, high TOM40 expression in the tumor tissues was associated with poor overall survival and disease specific survival. TOM40 knockdown in the NPC cell lines inhibited their proliferation in vitro and in vivo. Furthermore, TOM40 silencing also increased intracellular production of reactive oxygen species (ROS) and decreased mitochondrial membrane potential (MMP). Mechanistically, the anti-tumor effects of TOM40 silencing were dependent on the inhibition of AKT/mTOR signaling and activation of p53 signaling. To summarize, TOM40 mediates NPC progression through ROS-mediated AKT/mTOR and p53 signaling. Our findings highlight the potential of TOM40 as a therapeutic target for NPC.

The Translocase of the Outer Mitochondrial Membrane (TOM40) is required for mitochondrial dynamics and neuronal integrity in Dorsal Root Ganglion Neurons

Polymorphisms and altered expression of the Translocase of the Outer Mitochondrial Membrane - 40 kD (Tom40) are observed in neurodegenerative disease subjects. We utilized in vitro cultured dorsal root ganglion (DRG) neurons to investigate the association of TOM40 depletion to neurodegeneration, and to unravel the mechanism of neurodegeneration induced by decreased levels of TOM40 protein. We provide evidence that severity of neurodegeneration induced in the TOM40 depleted neurons increases with the increase in the depletion of TOM40 and is exacerbated by an increase in the duration of TOM40 depletion. We also demonstrate that TOM40 depletion causes a surge in neuronal calcium levels, decreases mitochondrial motility, increases mitochondrial fission, and decreases neuronal ATP levels. We observed that alterations in the neuronal calcium homeostasis and mitochondrial dynamics precede BCL-xl and NMNAT1 dependent neurodegenerative pathways in the TOM40 depleted neurons. This data also suggests that manipulation of BCL-xl and NMNAT1 may be of therapeutic value in TOM40 associated neurodegenerative disorders.

A trans-omics assessment of gene-gene interaction in early-stage NSCLC

Epigenome-wide gene-gene (G × G) interactions associated with non-small-cell lung cancer (NSCLC) survival may provide insights into molecular mechanisms and therapeutic targets. Hence, we proposed a three-step analytic strategy to identify significant and robust G × G interactions that are relevant to NSCLC survival. In the first step, among 49 billion pairs of DNA methylation probes, we identified 175 775 G × G interactions with PBonferroni  ≤ 0.05 in the discovery phase of epigenomic analysis; among them, 15 534 were confirmed with P ≤ 0.05 in the validation phase. In the second step, we further performed a functional validation for these G × G interactions at the gene expression level by way of a two-phase (discovery and validation) transcriptomic analysis, and confirmed 25 significant G × G interactions enriched in the 6p21.33 and 6p22.1 regions. In the third step, we identified two G × G interactions using the trans-omics analysis, which had significant (P ≤ 0.05) epigenetic cis-regulation of transcription and robust G × G interactions at both the epigenetic and transcriptional levels. These interactions were cg14391855 × cg23937960 (βinteraction  = 0.018, P = 1.87 × 10-12 ), which mapped to RELA × HLA-G (βinteraction  = 0.218, P = 8.82 × 10-11 ) and cg08872738 × cg27077312 (βinteraction  = -0.010, P = 1.16 × 10-11 ), which mapped to TUBA1B × TOMM40 (βinteraction =-0.250, P = 3.83 × 10-10 ). A trans-omics mediation analysis revealed that 20.3% of epigenetic effects on NSCLC survival were significantly (P = 0.034) mediated through transcriptional expression. These statistically significant trans-omics G × G interactions can also discriminate patients with high risk of mortality. In summary, we identified two G × G interactions at both the epigenetic and transcriptional levels, and our findings may provide potential clues for precision treatment of NSCLC.

TOMM34 promotes cell proliferation, migration, and invasion of OSCC and modulates mitochondrial function

BACKGROUND

34-kDa translocase of the outer mitochondrial membrane (TOMM34) has been reported highly expressed in many cancers and is positively correlated to poorer prognosis. Our prior study showed TOMM34 is highly expressed in oral squamous cell carcinoma (OSCC) and is closely related to TNM classification and tumor size. TOMM34 is also associated with lymph node metastasis and poorer overall survival and disease-free survival in HPV-negative OSCC.

METHODS

We knocked down TOMM34 in OSCC cells (SCC15, HPV positive; Cal27, HPV negative) with siRNA and over-expressed with plasmids. The effects of TOMM34 on cell proliferation, migration and invasion abilities were detected by EdU assay, CCK-8 assay, wound-healing assay, and Transwell assay. We also detected the mitochondrial morphology and the intracellular Reactive Oxygen Species (ROS) level by fluorescence staining and flow cytometry. Finally, we monitored the protein levels of ERK pathway-related molecules.

RESULTS

TOMM34 knockdown decreased the proliferation in SCC15 and Cal27, and weakened the migration and invasion abilities as well. Mitochondria became shorter, in the shape of dots or short rods, suggesting that mitochondrial damage occurred. Intracellular ROS levels increased significantly after knockdown TOMM34 and decreased after over-expressing TOMM34. The phosphorylation levels of ERK1/2 and MEK1/2 in SCC15 were significantly higher than in Cal27. Besides, the phosphorylation levels of ERK1/2 and MEK1/2 were inhibited in SCC15 after knockdown of TOMM34, but not in Cal27.

CONCLUSION

TOMM34 promotes the cell proliferation, migration, and invasion of OSCC. In addition, TOMM34 participates in maintaining the mitochondrial shape and reducing the intracellular ROS level to protect cancer cells. Furthermore, TOMM34 increases the activity of ERK1/2 and MEK1/2 in HPV-positive OSCC cells but not in HPV-negative.

Integrative analyses of a mitophagy-related gene signature for predicting prognosis in patients with uveal melanoma

We aimed to create a mitophagy-related risk model via data mining of gene expression profiles to predict prognosis in uveal melanoma (UM) and develop a novel method for improving the prediction of clinical outcomes. Together with clinical information, RNA-seq and microarray data were gathered from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. ConsensusClusterPlus was used to detect mitophagy-related subgroups. The genes involved with mitophagy, and the UM prognosis were discovered using univariate Cox regression analysis. In an outside population, a mitophagy risk sign was constructed and verified using least absolute shrinkage and selection operator (LASSO) regression. Data from both survival studies and receiver operating characteristic (ROC) curve analyses were used to evaluate model performance, a bootstrap method was used test the model. Functional enrichment and immune infiltration were examined. A risk model was developed using six mitophagy-related genes (ATG12, CSNK2B, MTERF3, TOMM5, TOMM40, and TOMM70), and patients with UM were divided into low- and high-risk subgroups. Patients in the high-risk group had a lower chance of living longer than those in the low-risk group (p < 0.001). The ROC test indicated the accuracy of the signature. Moreover, prognostic nomograms and calibration plots, which included mitophagy signals, were produced with high predictive performance, and the risk model was strongly associated with the control of immune infiltration. Furthermore, functional enrichment analysis demonstrated that several mitophagy subtypes may be implicated in cancer, mitochondrial metabolism, and immunological control signaling pathways. The mitophagy-related risk model we developed may be used to anticipate the clinical outcomes of UM and highlight the involvement of mitophagy-related genes as prospective therapeutic options in UM. Furthermore, our study emphasizes the essential role of mitophagy in UM.

Inhibition of lysosomal acid β-glucosidase induces cell apoptosis via impairing mitochondrial clearance in pancreatic cancer

Sphingolipid metabolism plays an important role in the formation of cellular membranes and is associated with malignant potential and chemosensitivity of cancer cells. Sphingolipid degradation depends on multiple lysosomal glucosidases. We focused on acid β-glucosidase (GBA), a lysosomal enzyme the deficiency of which is related to mitochondrial dysfunction. We analyzed the function of GBA in pancreatic ductal adenocarcinoma (PDAC). Human PDAC cell lines (PANC-1, BxPC-3 and AsPC-1) were examined under conditions of GBA knockdown via the short interfering RNA (siRNA) method. We assessed the morphological changes, GBA enzyme activity, GBA protein expression, cell viability, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) and mitophagy flux of PDAC cells. The GBA protein level and enzyme activity differed among cell lines. GBA knockdown suppressed cell proliferation and induced apoptosis, especially in PANC-1 and BxPC-3 cells, with low GBA enzyme activity. GBA knockdown also decreased the MMP and impaired mitochondrial clearance. This impaired mitochondrial clearance further induced dysfunctional mitochondria accumulation and ROS generation in PDAC cells, inducing apoptosis. The antiproliferative effects of the combination of GBA suppression and gemcitabine were higher than those of gemcitabine alone. These results showed that GBA suppression exerts a significant antitumor effect and may have therapeutic potential in the clinical treatment of PDAC.

Alpinetin ameliorates bone loss in LPS-induced inflammation osteolysis via ROS mediated P38/PI3K signaling pathway

BACKGROUND AND OBJECTIVE

Bone loss occurs in several inflammatory diseases because of chronic persistent inflammation that activates osteoclasts (OCs) to increase bone resorption. Currently available antiresorptive drugs have severe side effects or contraindications. Herein, we explored the effects and mechanism of Alpinetin (Alp) on receptor activator of nuclear factor κB ligand (RANKL)-mediated OCs differentiation, function, and in inflammatory osteolysis of mice.

METHOD

Primary mouse bone marrow-derived macrophages (BMMs) induced by RANKL and macrophage colony-stimulating factor (M-CSF) were utilized to test the impact of Alp on OCs differentiation, function, and intracellular reactive oxygen species (ROS) production, respectively. Expression of oxidant stress relevant factors and OCs specific genes were assessed via real-time quantitative PCR. Further, oxidative stress-related factors, NF-κB, MAPK, PI3K/AKT/GSK3-β, and NFATc1 pathways were examined via Western blot. Finally, LPS-induced mouse calvarial osteolysis was used to investigate the effect of Alp on inflammatory osteolysis in vivo.

RESULT

Alp suppressed OCs differentiation and resorption function, and down-regulated the ROS production. Alp inhibited IL-1β, TNF-α and osteoclast-specific gene transcription. It also blocked the gene and protein expression of Nox1 and Keap1, but enhanced Nrf2, CAT, and HO-1 protein levels. Additionally, Alp suppressed the phosphorylation of PI3K and P38, and restrained the expression of osteoclast-specific gene Nfatc1 and its auto-amplification, hence minimizing LPS-induced osteolysis in mice.

CONCLUSION

Alp is a novel candidate or therapeutics for the osteoclast-associated inflammatory osteolytic ailment.

Exosome mediated Tom40 delivery protects against hydrogen peroxide-induced oxidative stress by regulating mitochondrial function

Mitochondrial dysfunction is a hallmark of neurodegeneration. The expression level of Tom40, a crucial mitochondrial membrane protein, is significantly reduced in neurodegenerative disease subjects. Tom40 overexpression studies have shown to protect the neurons against oxidative stress by improving mitochondrial function. Thus, successful delivery of Tom40 protein to the brain could lead to a novel therapy for neurodegenerative diseases. However, delivering protein to the cell may be difficult. Especially the blood-brain barrier (BBB) is a big hurdle to clear in order to deliver the protein to the brain. In the current study, we engineered exosomes, which are the extracellular vesicles of endosomal origin, and able to cross BBB as delivery vehicles packing human Tom40. We found Tom40 protein delivery by the exosome successfully protected the cells against hydrogen peroxide-induced oxidative stress. This result suggests that exosome-mediated delivery of Tom40 may potentially be useful in restoring mitochondrial functions and alleviating oxidative stress in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases.

Calotropis gigantea stem bark extracts inhibit liver cancer induced by diethylnitrosamine

Several fractions of Calotropis gigantea extracts have been proposed to have potential anticancer activity in many cancer models. The present study evaluated the anticancer activity of C. gigantea stem bark extracts in liver cancer HepG2 cells and diethylnitrosamine (DEN)-induced primary liver cancer in rats. The carcinogenesis model induced by DEN administration has been widely used to study pathophysiological features and responses in rats that are comparable to those seen in cancer patients. The dichloromethane (CGDCM), ethyl acetate, and water fractions obtained from partitioning crude ethanolic extract were quantitatively analyzed for several groups of secondary metabolites and calactin contents. A combination of C. gigantea stem bark extracts with doxorubicin (DOX) was assessed in this study to demonstrate the enhanced cytotoxic effect to cancer compared to the single administration. The combination of DOX and CGDCM, which had the most potential cytotoxic effect in HepG2 cells when compared to the other three fractions, significantly increased cytotoxicity through the apoptotic effect with increased caspase-3 expression. This combination treatment also reduced ATP levels, implying a correlation between ATP and apoptosis induction. In a rat model of DEN-induced liver cancer, treatment with DOX, C. gigantea at low (CGDCM-L) and high (CGDCM-H) doses, and DOX + CGDCM-H for 4 weeks decreased the progression of liver cancer by lowering the liver weight/body weight ratio and the occurrence of liver hyperplastic nodules, fibrosis, and proliferative cells. The therapeutic applications lowered TNF-α, IL-6, TGF-β, and α-SMA inflammatory cytokines in a similar way, implying that CGDCM had a curative effect against the inflammation-induced liver carcinogenesis produced by DEN exposure. Furthermore, CGDCM and DOX therapy decreased ATP and fatty acid synthesis in rat liver cancer, which was correlated with apoptosis inhibition. CGDCM reduced cleaved caspase-3 expression in liver cancer rats when used alone or in combination with DOX, implying that apoptosis-inducing hepatic carcinogenesis was suppressed. Our results also verified the low toxicity of CGDCM injection on the internal organs of rats. Thus, this research clearly demonstrated a promising, novel anticancer approach that could be applied in future clinical studies of CGDCM and combination therapy.

A Biochemical and Structural Understanding of TOM Complex Interactions and Implications for Human Health and Disease

The central role mitochondria play in cellular homeostasis has made its study critical to our understanding of various aspects of human health and disease. Mitochondria rely on the translocase of the outer membrane (TOM) complex for the bulk of mitochondrial protein import. In addition to its role as the major entry point for mitochondrial proteins, the TOM complex serves as an entry pathway for viral proteins. TOM complex subunits also participate in a host of interactions that have been studied extensively for their function in neurodegenerative diseases, cardiovascular diseases, innate immunity, cancer, metabolism, mitophagy and autophagy. Recent advances in our structural understanding of the TOM complex and the protein import machinery of the outer mitochondrial membrane have made structure-based therapeutics targeting outer mitochondrial membrane proteins during mitochondrial dysfunction an exciting prospect. Here, we describe advances in understanding the TOM complex, the interactome of the TOM complex subunits, the implications for the development of therapeutics, and our understanding of the structure/function relationship between components of the TOM complex and mitochondrial homeostasis.

Potential therapeutic targets shared between leishmaniasis and cancer

The association of leishmaniasis and malignancies in human and animal models has been highlighted in recent years. The misdiagnosis of coexistence of leishmaniasis and cancer and the use of common drugs in the treatment of such diseases prompt us to further survey the molecular biology of Leishmania parasites and cancer cells. The information regarding common expressed proteins, as possible therapeutic targets, in Leishmania parasites and cancer cells is scarce. Therefore, the current study reviews proteins, and investigates the regulation and functions of several key proteins in Leishmania parasites and cancer cells. The up- and down-regulations of such proteins were mostly related to survival, development, pathogenicity, metabolic pathways and vital signalling in Leishmania parasites and cancer cells. The presence of common expressed proteins in Leishmania parasites and cancer cells reveals valuable information regarding the possible shared mechanisms of pathogenicity and opportunities for therapeutic targeting in leishmaniasis and cancers in the future.

Mitochondrial protein import dysfunction: mitochondrial disease, neurodegenerative disease and cancer

The majority of proteins localised to mitochondria are encoded by the nuclear genome, with approximately 1500 proteins imported into mammalian mitochondria. Dysfunction in this fundamental cellular process is linked to a variety of pathologies including neuropathies, cardiovascular disorders, myopathies, neurodegenerative diseases and cancer, demonstrating the importance of mitochondrial protein import machinery for cellular function. Correct import of proteins into mitochondria requires the co-ordinated activity of multimeric protein translocation and sorting machineries located in both the outer and inner mitochondrial membranes, directing the imported proteins to the destined mitochondrial compartment. This dynamic process maintains cellular homeostasis, and its dysregulation significantly affects cellular signalling pathways and metabolism. This review summarises current knowledge of the mammalian mitochondrial import machinery and the pathological consequences of mutation of its components. In addition, we will discuss the role of mitochondrial import in cancer, and our current understanding of the role of mitochondrial import in neurodegenerative diseases including Alzheimer's disease, Huntington's disease and Parkinson's disease.

Tetraspanin 1 promotes endometriosis leading to ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) reportedly develops from endometriosis. However, the molecular mechanism underlying its malignant progression to OCCC remains elusive. This study aimed to identify an essential gene in the malignant transformation of endometriosis to OCCC. We performed RNA sequencing in formalin‐fixed, paraffin‐embedded (FFPE) tissues of endometriosis (n = 9), atypical endometriosis (AtyEm) (n = 18), adjacent endometriosis to OCCC (AdjEm) (n = 7), and OCCC (n = 17). We found that tetraspanin 1 (TSPAN1) mRNA level was significantly increased by 2.4‐ (DESeq2) and 3.4‐fold (edgeR) in AtyEm and by 80.7‐ (DESeq2) and 101‐fold (edgeR) in OCCC relative to endometriosis. We confirmed that TSPAN1 protein level was similarly overexpressed in OCCC tissues and cell lines. In immortalized endometriosis cell lines, TSPAN1 overexpression enhanced cell growth and invasion. Mechanistically, TSPAN1 triggered AMP‐activated protein kinase (AMPK) activity, promoting endometriosis and cell growth. Upregulated levels of TSPAN1 are considered an early event in the development of high‐risk endometriosis that could progress to ovarian cancer. Our study suggests the potential of TSPAN1 as a screening candidate for high‐risk endometriosis.

Convergence of Plasma Metabolomics and Proteomics Analysis to Discover Signatures of High-Grade Serous Ovarian Cancer

Simple Summary

In-time diagnosing ovarian cancer, intractable cancer that has no symptoms can increase the survival of women. The aim of this study was to discover biomarkers from liquid biopsy samples using multi-omics approach, metabolomics and proteomics for the diagnosis of ovarian cancer. To verify our biomarker candidates, we conducted comparative analysis with other previous published studies. Despite the limitations of non-invasive samples, our findings are able to discover emerging properties through the interplay between metabolites and proteins and mechanism-based biomarkers through integrated protein and metabolite analysis.

Abstract

The 5-year survival rate in the early and late stages of ovarian cancer differs by 63%. In addition, a liquid biopsy is necessary because there are no symptoms in the early stage and tissue collection is difficult without using invasive methods. Therefore, there is a need for biomarkers to achieve this goal. In this study, we found blood-based metabolite or protein biomarker candidates for the diagnosis of ovarian cancer in the 20 clinical samples (10 ovarian cancer patients and 10 healthy control subjects). Plasma metabolites and proteins were measured and quantified using mass spectrometry in ovarian cancer patients and control groups. We identified the differential abundant biomolecules (34 metabolites and 197 proteins) and statistically integrated molecules of different dimensions to better understand ovarian cancer signal transduction and to identify novel biological mechanisms. In addition, the biomarker reliability was verified through comparison with existing research results. Integrated analysis of metabolome and proteome identified emerging properties difficult to grasp with the single omics approach, more reliably interpreted the cancer signaling pathway, and explored new drug targets. Especially, through this analysis, proteins (PPCS, PMP2, and TUBB) and metabolites (L-carnitine and PC-O (30:0)) related to the carnitine system involved in cancer plasticity were identified.

Detection of Ovarian Cancer through Exhaled Breath by Electronic Nose: A Prospective Study

BACKGROUND

Diagnostic methods for the early identification of ovarian cancer (OC) represent an unmet clinical need, as no reliable diagnostic tools are available. Here, we tested the feasibility of electronic nose (e-nose), composed of ten metal oxide semiconductor (MOS) sensors, as a diagnostic tool for OC detection.

METHODS

Women with suspected ovarian masses and healthy subjects had volatile organic compounds analysis of the exhaled breath using e-nose.

RESULTS

E-nose analysis was performed on breath samples collected from 251 women divided into three groups: 86 OC cases, 51 benign masses, and 114 controls. Data collected were analyzed by Principal Component Analysis (PCA) and K-Nearest Neighbors' algorithm (K-NN). A first 1-K-NN (cases vs. controls) model has been developed to discriminate between OC cases and controls; the model performance tested in the prediction gave 98% of sensitivity and 95% of specificity, when the strict class prediction was applied; a second 1-K-NN (cases vs. controls + benign) model was built by grouping the non-cancer groups (controls + benign), thus considering two classes, cases and controls + benign; the model performance in the prediction was of 89% for sensitivity and 86% for specificity when the strict class prediction was applied.

CONCLUSIONS

Our preliminary results suggested the potential role of e-nose for the detection of OC. Further studies aiming to test the potential adoption of e-nose in the early diagnosis of OC are needed.