Novel copper complex CTB regulates methionine cycle induced TERT hypomethylation to promote HCC cells senescence via mitochondrial SLC25A26

Targeting TM4SF1 promotes tumor senescence enhancing CD8+ T cell cytotoxic function in hepatocellular carcinoma

BACKGROUND/AIMS

Transmembrane 4 L six family member 1 (TM4SF1) is highly expressed and contributes to the progression of various malignancies. However, how it modulates hepatocellular carcinoma (HCC) progression and senescence remains to be elucidated.

METHODS

TM4SF1 expression in HCC samples was evaluated using immunohistochemistry and flow cytometry. Cellular senescence was assessed through SA-β-gal activity assays and Western blot analysis. TM4SF1-related protein interactions were investigated using immunoprecipitation-mass spectrometry, co-immunoprecipitation, bimolecular fluorescence complementation, and immunofluorescence. Tumor-infiltrating immune cells were analyzed by flow cytometry. The HCC mouse model was established via hydrodynamic tail vein injection.

RESULTS

TM4SF1 was highly expressed in human HCC samples and murine models. Knockdown of TM4SF1 suppressed HCC proliferation both in vitro and in vivo, inducing non-secretory senescence through upregulation of p16 and p21. TM4SF1 enhanced the interaction between AKT1 and PDPK1, thereby promoting AKT phosphorylation, which subsequently downregulated p16 and p21. Meanwhile, TM4SF1-mediated AKT phosphorylation enhanced PD-L1 expression while reducing major histocompatibility complex class I level on tumor cells, leading to impaired cytotoxic function of CD8+ T cells and an increased proportion of exhausted CD8+ T cells. In clinical HCC samples, elevated TM4SF1 expression was associated with resistance to anti-PD-1 immunotherapy. Targeting TM4SF1 via adeno-associated virus induced tumor senescence, reduced tumor burden and synergistically enhanced the efficacy of anti-PD-1 therapy.

CONCLUSION

Our results revealed that TM4SF1 regulated tumor cell senescence and immune evasion through the AKT pathway, highlighting its potential as a therapeutic target in HCC, particularly in combination with first-line immunotherapy.

The Role of Mitochondrial Solute Carriers SLC25 in Cancer Metabolic Reprogramming: Current Insights and Future Perspectives

Cancer cells undergo remarkable metabolic changes to meet their high energetic and biosynthetic demands. The Warburg effect is the most well-characterized metabolic alteration, driving cancer cells to catabolize glucose through aerobic glycolysis to promote proliferation. Another prominent metabolic hallmark of cancer cells is their increased reliance on glutamine to replenish tricarboxylic acid (TCA) cycle intermediates essential for ATP production, aspartate and fatty acid synthesis, and maintaining redox homeostasis. In this context, mitochondria, which are primarily used to maintain energy homeostasis and support balanced biosynthesis in normal cells, become central organelles for fulfilling the heightened biosynthetic and energetic demands of proliferating cancer cells. Mitochondrial coordination and metabolite exchange with other cellular compartments are crucial. The human SLC25 mitochondrial carrier family, comprising 53 members, plays a pivotal role in transporting TCA intermediates, amino acids, vitamins, nucleotides, and cofactors across the inner mitochondrial membrane, thereby facilitating this cross-talk. Numerous studies have demonstrated that mitochondrial carriers are altered in cancer cells, actively contributing to tumorigenesis. This review comprehensively discusses the role of SLC25 carriers in cancer pathogenesis and metabolic reprogramming based on current experimental evidence. It also highlights the research gaps that need to be addressed in future studies. Understanding the involvement of these carriers in tumorigenesis may provide valuable novel targets for drug development.

Cross talk between genetics and biochemistry in the pathogenesis of hepatocellular carcinoma

The liver is a crucial organ in the regulation of metabolism, signaling, and homeostasis. Using recent advanced sequencing technologies, several mutations of genes in major metabolic and signaling pathways have been discovered in the pathogenesis of hepatocellular carcinoma (HCC). These gene signatures alter expression and ultimately affect biochemical pathways by modifying enzyme/protein levels, resulting in numerous clinical outcomes related to HCC. It comes with varying forms of genetic and biochemical alterations, associated with carbohydrate, lipid, nucleic acid, and amino acid metabolism, as well as signaling pathways linked to tumorigenesis. Here, we aim to summarize the main components and mechanisms involved in the progression of HCC with a special focus on the metabolic regulation of key effectors of tumorigenesis, through the crosstalk between genetics and biochemistry. This paper provides an overview of hepatocellular carcinoma, underlying the fundamental effect of gene variations on metabolic and signaling pathways. Since there is still an unmet need for biomarkers and novel therapeutic targets, some of these signature genes or proteins can be used as novel biomarkers for diagnosis, prognosis, and novel potential therapeutic targets for the treatment of HCC.

Fresh Insights Into SLC25A26: Potential New Therapeutic Target for Cancers: A Review

SLC25A26 is the only known human mitochondrial S-adenosylmethionine carrier encoding gene. Recent studies have shown that SLC25A26 is abnormally expressed in some cancers, such as cervical cancer, low-grade glioma, non-small cell lung cancer, and liver cancer, which suggests SLC25A26 can affect the occurrence and development of some cancers. This article in brief briefly reviewed mitochondrial S-adenosylmethionine carrier in different species and its encoding gene, focused on the association of SLC25A26 aberrant expression and some cancers as well as potential mechanisms, summarized its potential for cancer prognosis, and characteristics of mitochondrial diseases caused by SLC25A26 mutation. Finally, we provide a brief expectation that needs to be further investigated. We speculate that SLC25A26 will be a potential new therapeutic target for some cancers.

Cancer Therapeutic Potential and Prognostic Value of the SLC25 Mitochondrial Carrier Family: A Review

Transporters of the solute carrier family 25 (SLC25) regulate the intracellular distribution and concentration of nucleotides, amino acids, dicarboxylates, and vitamins within the mitochondrial and cytoplasmic matrices. This mechanism involves changes in mitochondrial function, regulation of cellular metabolism, and the ability to provide energy. In this review, important members of the SLC25 family and their pathways affecting tumorigenesis and progression are elucidated, highlighting the diversity and complexity of these pathways. Furthermore, the significant potential of the members of SLC25 as both cancer therapeutic targets and biomarkers will be emphasized.

ERO1α promotes the proliferation and inhibits apoptosis of colorectal cancer cells by regulating the PI3K/AKT pathway

Endoplasmic reticulum oxidoreductin 1α (ERO1α) is an oxidase that exists in the endoplasmic reticulum and plays an important role in regulating oxidized protein folding and tumor malignant progression. However, the specific role and mechanism of ERO1α in the progression of colorectal cancer (CRC) have not yet been fully elucidated. In this study, 280 specimens of CRC tissues and adjacent noncancerous tissues were collected to detect the expression of ERO1α and analyze the clinical significance. ERO1α was stably knocked-down in RKO and HT29 CRC cells to investigate its function and mechanism in vitro and in vivo. We found that ERO1α was remarkably upregulated in CRC tissues and high ERO1α expression is associated with N stage and poor prognosis of CRC patients. ERO1α knockdown in CRC cells significantly inhibited the proliferation and induced apoptosis while inactivating the PI3K/AKT pathway. Rescue assays revealed that AKT activator 740Y-P could reverse the effects on proliferation and apoptosis of ERO1α knockdown in CRC cells. In vivo tumorigenicity assay also confirmed that ERO1α knockdown suppressed tumor growth. Taken together, our findings demonstrated ERO1α promotes the proliferation and inhibits apoptosis of CRC cells by regulating the PI3K/AKT pathway. High expression of ERO1α is associated with poor prognosis in CRC patients, and ERO1α could be a potential therapeutic target for CRC.

Copper-mediated novel cell death pathway in tumor cells and implications for innovative cancer therapies

Previous investigations have unraveled an array of cellular demise modalities, encompassing apoptosis, necrosis, pyroptosis, iron death, and several others. These diverse pathways of cell death have been harnessed as therapeutic strategies for eradicating tumor cells. Recent scientific inquiries have unveiled a novel mode of cell death, namely copper death, which is contingent upon intracellular copper levels. Diverging from conventional cell death mechanisms, copper death exhibits a heightened reliance on mitochondrial respiration, specifically the tricarboxylic acid (TCA) cycle. Tumor cells exhibit distinctive metabolic profiles and an elevated copper content compared to their normal counterparts. The emergence of copper death presents a tantalizing prospect for targeted therapies in the realm of cancer treatment. Thus, the primary objective of this review is to introduce the proteins and intricate mechanisms underlying copper death, while comprehensively summarizing the extensive body of knowledge concerning its ramifications across diverse tumor types. The insights garnered from this comprehensive synthesis will serve as an invaluable reference for driving the development of tailor-made therapeutic interventions for tumors.

Construction of a Novel Cuproptosis-Related ceRNA Network-SNHG3/miR-1306-5p/PDHA1 and Identification of SNHG3 as a Prognostic Biomarker in Hepatocellular Carcinoma

The crucial role of competitive endogenous RNA (ceRNA) in the malignant biological behavior of tumors has been certificated. Nevertheless, the detailed function and molecular mechanism of ceRNA associated with cuproptosis in hepatocellular carcinoma (HCC) remains dismal. In this study, we first constructed a protein-protein interaction network and identified the module with the highest degree of aggregation degree. DLAT and PDHA1 were screened out of the module after differential expression and survival analysis. Next, we reverse-predicted the upstream miRNA and lncRNA from mRNA (DLAT, PDHA1) and successfully established the ceRNA network-SNHG3/miR-1306-5p/PDHA1. SNHG3 was identified to be an independent prognostic biomarker based on the outcome of univariate and multivariate Cox analyses. Subsequently, we implemented methylation, immune infiltration, and drug sensitivity analysis to investigate the potential biological functions of SNHG3 in HCC. In addition, SNHG3 expression was upregulated in liver cancer cell lines. In vitro functional assay revealed that SNHG3 knockdown significantly attenuated proliferation, migration, and invasion of liver cancer cells. In summary, SNHG3 exhibited oncogenic characterization via sponging miR-1306-5p to regulate PDHA1, which might function as a promising prognostic indicator and a potential therapeutic target for HCC and shed new light on the molecular mechanism of HCC progression.

The copper (II) complex of salicylate phenanthroline inhibits proliferation and induces apoptosis of hepatocellular carcinoma cells

In the present study, we investigated the antitumor effect and associated molecular mechanisms of the copper (II) complex of salicylate phenanthroline [Cu(sal)(phen)] against hepatocellular carcinoma (HCC). Cu(sal)(phen) inhibited the proliferation of HCC cells (HepG2 and HCC-LM9) and induced apoptosis of HCC cells in a dose-dependent manner by upregulating mitochondrial reactive oxygen species (ROS) production. The expression of the antiapoptotic proteins survivin and Bcl-2 was decreased, while the expression of the DNA damage marker γ-H₂ AX and the apoptotic marker cleaved PARP was upregulated with Cu(sal)(phen) treatment. In vivo, the growth of HepG2 subcutaneous xenograft tumors was greatly attenuated by Cu(sal)(phen) treatment. Immunohistochemistry staining showed that the expression of survivin, Bcl-2, and Ki67 in the tumor was downregulated by Cu(sal)(phen). Toxicity experiments with BALB/c mice revealed that Cu(sal)(phen) is a relatively safe drug. Our results indicate that Cu(sal)(phen) possesses great potential as a therapeutic drug for HCC.

Selective Methionine Pool Exhaustion Mediated by a Sequential Positioned MOF Nanotransformer for Intense Cancer Immunotherapy

Cancer cells are addictive to exogenous methionine to gear toward tumor proliferation. Meanwhile, they can replenish methionine pool from polyamine metabolism through a methionine salvage pathway. However, the current developed therapeutic tactics for methionine depletion are still facing great challenges in terms of the selectivity, safety, and efficiency. Herein, a sequential positioned metal-organic framework (MOF) nanotransformer is designed to selectively exhaust the methionine pool via inhibiting the uptake of methionine and throttling its salvage pathway for enhanced cancer immunotherapy. The MOF nanotransformer can restrain the open source and reduce the reflux of methionine to exhaust the methionine pool of cancer cells. Moreover, the intracellular traffic routes of the sequential positioned MOF nanotransformer match well with the distribution of polyamines, which is conducive to the oxidation of polyamines via its responsive deformability and nanozyme-augmented Fenton-like reaction for the final exhaustion of intracellular methionine. These results verify that the well-designed platform cannot only kill cancer cells efficiently but also promote the infiltration of CD8 and CD4 T cells for intensive cancer immunotherapy. Overall, it is believed that this work will inspire the construction of novel MOF-based antineoplastic platforms and provide new insights into the development of metabolic-related immunotherapy.

Oroxylin A activates ferritinophagy to induce hepatic stellate cell senescence against hepatic fibrosis by regulating cGAS-STING pathway

In recent study, the pathological mechanism of liver fibrosis has been associated with hepatic stellate cell (HSC) senescence. Targeted induction of HSC senescence is considered as a new strategy to remove activated HSC. Nevertheless, little is known about the role of ferritinophagy in cell senescence. In this study, we reported that Oroxylin A from Scutellaria baicalensis Georgi can regulate HSC senescence induced by ferritinophagy through the cGAS-STING pathway to reduce liver fibrosis. We first found that Oroxylin A treatment alleviated the pathological changes of liver fibrosis, reduced collagen deposition, and significantly inhibited liver fibrosis. Interestingly, Oroxylin A treatment can activate HSC ferritinophagy and further induce HSC senescence. It is noteworthy that ferritinophagy is mediated by nuclear receptor coactivator 4 (NCOA4), an important selective mediator for ferritin degradation. NCOA4 siRNA causes Oroxylin A to reduce the degree of telomerase activity in HSCs and induce the expression of senescence markers, such as SA-β-Gal and related marker proteins. Importantly, the cGAS-STING pathway is crucial to the activation of HSC ferritinophagy by Oroxylin A. Specifically, Oroxylin A can promote the secretion of cytokines like IFN-β by the cGAS-STING pathway to regulate ferritinophagy. cGAS siRNA resulted in a dose-dependent decrease in the expression of NCOA4, a significant reduction in the expression level of autophagy-related phenotype, and a decrease in the content of ROS and iron ions in HSCs. In conclusion, we identified the new role of ferritinophagy and the GAS-STING pathway in Oroxylin A -mediated anti-hepatic fibrosis.

Cuproptosis-related genes score: A predictor for hepatocellular carcinoma prognosis, immunotherapy efficacy, and metabolic reprogramming

Background

Cuproptosis is a newly identified type of programmed cell death, characterized by aggregation of mitochondrial lipoylated proteins and the destabilization of Fe-S cluster proteins triggered by copper. However, its role in hepatocellular carcinoma (HCC) remains unclear.

Methods

We analyzed the expression and prognostic significance of cuproptosis-related genes using the data obtained from TCGA and ICGC datasets. A cuproptosis-related genes (CRG) score was constructed and validated via least absolute shrinkage and selection operator (LASSO) Cox regression, multivariate Cox regression and nomogram model. The metabolic features, immune profile and therapy guidance of CRG-classified HCC patients were processed via R packages. The role of kidney-type glutaminase (GLS) in cuproptosis and sorafenib treatment has been confirmed via GLS knockdown.

Results

The CRG score and its nomogram model performed well in predicting prognosis of HCC patients based on the TCGA cohort (training set), ICGC cohort and GEO cohort (validation set). The risk score was proved as an independent predictor for overall survival (OS) of HCC. The area under the curves (AUCs) of the model in the training and validation cohorts were all around 0.83 (TCGA, 1- year), 0.73 (TCGA, 3- year), 0.92 (ICGC, 1- year), 0.75 (ICGC, 3- year), 0.77 (GEO, 1- year), 0.76(GEO, 3- year). Expression levels of metabolic genes and subtypes of immune cells, and sorafenib sensitiveness varied significantly between the high-CRG group and low-CRG group. One of the model-included gene, GLS, might be involved in the process of cuproptosis and sorafenib treatment in HCC cell line.

Conclusion

The five cuproptosis-related genes model contributed to prognostic prediction and provided a new sight for cuproptosis-related therapy in HCC.

A novel prognostic scoring model based on copper homeostasis and cuproptosis which indicates changes in tumor microenvironment and affects treatment response

Background: Intracellular copper homeostasis requires a complex system. It has shown considerable prospects for intervening in the tumor microenvironment (TME) by regulating copper homeostasis and provoking cuproptosis. Their relationship with hepatocellular carcinoma (HCC) remains elusive. Methods: In TCGA and ICGC datasets, LASSO and multivariate Cox regression were applied to obtain the signature on the basis of genes associated with copper homeostasis and cuproptosis. Bioinformatic tools were utilized to reveal if the signature was correlated with HCC characteristics. Single-cell RNA sequencing data analysis identified differences in tumor and T cells' pathway activity and intercellular communication of immune-related cells. Real-time qPCR analysis was conducted to measure the genes' expression in HCC and adjacent normal tissue from 21 patients. CCK8 assay, scratch assay, transwell, and colony formation were conducted to reveal the effect of genes on in vitro cell proliferation, invasion, migration, and colony formation. Results: We constructed a five-gene scoring system in relation to copper homeostasis and cuproptosis. The high-risk score indicated poor clinical prognosis, enhanced tumor malignancy, and immune-suppressive tumor microenvironment. The T cell activity was markedly reduced in high-risk single-cell samples. The high-risk HCC patients had a better expectation of ICB response and reactivity to anti-PD-1 therapy. A total of 156 drugs were identified as potential signature-related drugs for HCC treatment, and most were sensitive to high-risk patients. Novel ligand-receptor pairs such as FASLG, CCL, CD40, IL2, and IFN-Ⅱ signaling pathways were revealed as cellular communication bridges, which may cause differences in TME and immune function. All crucial genes were differentially expressed between HCC and paired adjacent normal tissue. Model-constructed genes affected the phosphorylation of mTOR and AKT in both Huh7 and Hep3B cells. Knockdown of ZCRB1 impaired the proliferation, invasion, migration, and colony formation in HCC cell lines. Conclusion: We obtained a prognostic scoring system to forecast the TME changes and assist in choosing therapy strategies for HCC patients. In this study, we combined copper homeostasis and cuproptosis to show the overall potential risk of copper-related biological processes in HCC for the first time.

Oroxylin A regulates cGAS DNA hypermethylation induced by methionine metabolism to promote HSC senescence

Relevant studies have recognized the important role of hepatic stellate cell (HSC) senescence in anti-liver fibrosis. Cellular senescence is believed to be regulated by the cGAS-STING signaling pathway. However, underlying exact mechanisms of cGAS-STING pathway in hepatic stellate cell senescence are still unclear. Here, we found that Oroxylin A could promote senescence in HSC by activating the cGAS-STING pathway. Moreover, activation of the cGAS-STING pathway was dependent on DNMT3A downregulation, which suppressed cGAS gene DNA methylation. Interestingly, the attenuation of DNMT activity relied on the reduction of methyl donor SAM level. Noteworthy, the downregulation of SAM levels implied the imbalance of methionine cycle metabolism, and MAT2A was considered to be an important regulatory enzyme in metabolic processes. In vivo experiments also indicated that Oroxylin A induced senescence of HSCs in mice with liver fibrosis, and DNMT3A overexpression partly offset this effect. In conclusion, we discovered that Oroxylin A prevented the methylation of the cGAS gene by preventing the production of methionine metabolites, which promoted the senescence of HSCs. This finding offers a fresh hypothesis for further research into the anti-liver fibrosis mechanism of natural medicines.

The Cuproptosis-Related Long Noncoding RNA Signature Predicts Prognosis and Immune Cell Infiltration in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC), ranking as one of the most common malignant tumors, is one of the leading causes of cancer death, with a poor prognosis. Cuproptosis, a novel programmed cell death modality that has just been confirmed recently, may play an important role in HCC prognosis. Long noncoding RNA (LncRNA) is a key participant in tumorigenesis and immune responses. It may be of great significance to predict HCC based on cuproptosis genes and their related LncRNA.

Methods

The sample data on HCC patients were obtained from The Cancer Genome Atlas (TCGA) database. Combined with cuproptosis-related genes collected from the literature search, expression analysis was carried out to find cuproptosis genes and their related LncRNAs significantly expressed in HCC. The prognostic model was constructed by least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression. The feasibility of these signature LncRNAs used for the evaluation of the overall survival rate in HCC patients as independent factors was investigated. The expression profile of cuproptosis, immune cell infiltration, and the status of somatic mutation were analyzed and compared.

Results

A prognostic model of HCC consisting of seven cuproptosis gene-related LncRNA signatures was constructed. Multiple verification methods have showed that this model can accurately predict the prognosis of HCC patients. It was showed that the classified high-risk group under the risk score of this model had worse survival status, more significant expression of the immune function, and higher mutation frequency. During the analysis, the cuproptosis gene CDKN2A was found to be most closely related to LncRNA DDX11-AS1 in the expression profile of HCC patients.

Conclusion

The cuproptosis-related signature LncRNA in HCC was identified, on the basis of which a model was constructed, and it was verified that it can be used to predict the prognosis of HCC patients. The potential role of these cuproptosis-related signature LncRNAs as new targets for disease therapy in antagonizing HCC development was discussed.

Mitochondrial transport and metabolism of the major methyl donor and versatile cofactor S-adenosylmethionine, and related diseases: A review†

S-adenosyl-L-methionine (SAM) is a coenzyme and the most commonly used methyl-group donor for the modification of metabolites, DNA, RNA and proteins. SAM biosynthesis and SAM regeneration from the methylation reaction product S-adenosyl-L-homocysteine (SAH) take place in the cytoplasm. Therefore, the intramitochondrial SAM-dependent methyltransferases require the import of SAM and export of SAH for recycling. Orthologous mitochondrial transporters belonging to the mitochondrial carrier family have been identified to catalyze this antiport transport step: Sam5p in yeast, SLC25A26 (SAMC) in humans, and SAMC1-2 in plants. In mitochondria SAM is used by a vast number of enzymes implicated in the following processes: the regulation of replication, transcription, translation, and enzymatic activities; the maturation and assembly of mitochondrial tRNAs, ribosomes and protein complexes; and the biosynthesis of cofactors, such as ubiquinone, lipoate, and molybdopterin. Mutations in SLC25A26 and mitochondrial SAM-dependent enzymes have been found to cause human diseases, which emphasizes the physiological importance of these proteins.

Chemoprevention of Lung Cancer with a Combination of Mitochondria-Targeted Compounds

Simple Summary

Previous reports showed that mitochondria-targeted honokiol and mitochondria-targeted lonidamine potently inhibit complex-I- and complexes-I/II-induced respiration and cancer cell proliferation. In this study, we investigated the efficacy of combining mitochondria-targeted honokiol and mitochondria-targeted lonidamine treatments for lung cancer prevention. We found that their combination exhibited striking tumor inhibition in the benzo[a]pyrene-induced murine lung tumor model without causing detectable side effects. Using single-cell RNA sequencing, we found combined treatment has a clear advantage in that it can significantly inhibit two oncogenic pathways—STAT3 signaling and AKT/mTOR/p70S6K signaling. Such dual inhibition may contribute to the greater efficacy of the combined drug treatment. Therefore, the combination provides a novel option for lung cancer chemoprevention.

Abstract

Combined treatment targeting mitochondria may improve the efficacy of lung cancer chemoprevention. Here, mitochondria-targeted honokiol (Mito-HNK), an inhibitor of mitochondrial complex I and STAT3 phosphorylation, and mitochondria-targeted lonidamine (Mito-LND), an inhibitor of mitochondrial complexes I/II and AKT/mTOR/p70S6K signaling, were evaluated for their combinational chemopreventive efficacy on mouse lung carcinogenesis. All chemopreventive treatments began one-week post-carcinogen treatment and continued daily for 24 weeks. No evidence of toxicity (including liver toxicity) was detected by monitoring serum levels of alanine aminotransferase and aspartate aminotransferase enzymes. Mito-HNK or Mito-LND treatment alone reduced tumor load by 56% and 48%, respectively, whereas the combination of Mito-HNK and Mito-LND reduced tumor load by 83%. To understand the potential mechanism(s) of action for the observed combinatorial effects, single-cell RNA sequencing was performed using mouse tumors treated with Mito-HNK, Mito-LND, and their combination. In lung tumor cells, Mito-HNK treatment blocked the expression of genes involved in mitochondrial complex ǀ, oxidative phosphorylation, glycolysis, and STAT3 signaling. Mito-LND inhibited the expression of genes for mitochondrial complexes I/II, oxidative phosphorylation, and AKT/mTOR/p70S6K signaling in lung tumor cells. In addition to these changes, a combination of Mito-HNK with Mito-LND decreased arginine and proline metabolism, N-glycan biosynthesis, and tryptophan metabolism in lung tumor cells. Our results demonstrate that Mito-LND enhanced the antitumor efficacy of Mito-HNK, where both compounds inhibited common targets (oxidative phosphorylation) as well as unique targets for each agent (STAT3 and mTOR signaling). Therefore, the combination of Mito-HNK with Mito-LND may present an effective strategy for lung cancer chemoprevention.

Aberrant Expression of Mitochondrial SAM Transporter SLC25A26 Impairs Oocyte Maturation and Early Development in Mice

The immature germinal vesicle (GV) oocytes proceed through metaphase I (MI) division, extrude the first polar body, and become mature metaphase II (MII) oocytes for fertilization which is followed by preimplantation and postimplantation development until birth. Slc25a26 is the gene encoding S-adenosylmethionine carrier (SAMC), a member of the mitochondrial carrier family. Its major function is to catalyze the uptake of S-adenosylmethionine (SAM) from cytosol into mitochondria, which is the only known mitochondrial SAM transporter. In the present study, we demonstrated that excessive SLC25A26 accumulation in mouse oocytes mimicked naturally aged oocytes and resulted in lower oocyte quality with decreased maturation rate and increased reactive oxygen species (ROS) by impairing mitochondrial function. Increased level of Slc25a26 gene impacted gene expression in mouse oocytes such as mt-Cytb which regulates mitochondrial respiratory chain. Furthermore, increased level of Slc25a26 gene in fertilized oocytes slightly compromised blastocyst formation, and Slc25a26 knockout mice displayed embryonic lethality around 10.5 dpc. Taken together, our results showed that Slc25a26 gene plays a critical role in oocyte maturation and early mouse development.

A hypoxia-linked gene signature for prognosis prediction and evaluating the immune microenvironment in patients with hepatocellular carcinoma

Background

Previous research indicates that hypoxia critically affects the initiation and progression of hepatocellular carcinoma (HCC). Nevertheless, the molecular mechanisms responsible for HCC development are poorly understood. Herein, we purposed to build a prognostic model using hypoxia-linked genes to predict patient prognosis and investigate the relationship of hypoxia with immune status in the tumor microenvironment (TME).

Methods

The training cohort included transcriptome along with clinical data abstracted from The Cancer Genome Atlas (TCGA). The validation cohort was abstracted from Gene Expression Omnibus (GEO). Univariate along with multivariate Cox regression were adopted to create the prediction model. We divided all patients into low- and high-risk groups using median risk scores. The estimation power of the prediction model was determined with bioinformatic tools.

Results

Six hypoxia-linked genes, HMOX1, TKTL1, TPI1, ENO2, LDHA, and SLC2A1, were employed to create an estimation model. Kaplan-Meier, ROC curve, and risk plot analyses demonstrated that the estimation potential of the risk model was satisfactory. Univariate along with multivariate regression data illustrated that the risk model could independently predict the overall survival (OS). A nomogram integrating the risk signature and clinicopathological characteristics showed a good potential to estimate HCC prognosis. Gene set enrichment analysis (GSEA) revealed that genes associated with cell proliferation and metabolism cascades were abundant in high-risk group. Furthermore, the signature showed a strong ability to distinguish the two groups in terms of immune status.

Conclusions

A prediction model for predicting HCC prognosis using six hypoxia-linked genes was designed in this study, facilitating the diagnosis and treatment of HCC.

High expression of PARD3 predicts poor prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most commonly cancers with poor prognosis and drug response. Identifying accurate therapeutic targets would facilitate precision treatment and prolong survival for HCC. In this study, we analyzed liver hepatocellular carcinoma (LIHC) RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA), and identified PARD3 as one of the most significantly differentially expressed genes (DEGs). Then, we investigated the relationship between PARD3 and outcomes of HCC, and assessed predictive capacity. Moreover, we performed functional enrichment and immune infiltration analysis to evaluate functional networks related to PARD3 in HCC and explore its role in tumor immunity. PARD3 expression levels in 371 HCC tissues were dramatically higher than those in 50 paired adjacent liver tissues (p < 0.001). High PARD3 expression was associated with poor clinicopathologic feathers, such as advanced pathologic stage (p = 0.002), vascular invasion (p = 0.012) and TP53 mutation (p = 0.009). Elevated PARD3 expression also correlated with lower overall survival (OS, HR = 2.08, 95% CI = 1.45-2.98, p < 0.001) and disease-specific survival (DSS, HR = 2.00, 95% CI = 1.27-3.16, p = 0.003). 242 up-regulated and 71 down-regulated genes showed significant association with PARD3 expression, which were involved in genomic instability, response to metal ions, and metabolisms. PARD3 is involved in diverse immune infiltration levels in HCC, especially negatively related to dendritic cells (DCs), cytotoxic cells, and plasmacytoid dendritic cells (pDCs). Altogether, PARD3 could be a potential prognostic biomarker and therapeutic target of HCC.

Remodeling of Mitochondrial Plasticity: The Key Switch from NAFLD/NASH to HCC

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third-leading cause of cancer-related mortality. Currently, the global burden of nonalcoholic fatty liver disease (NAFLD) has dramatically overcome both viral and alcohol hepatitis, thus becoming the main cause of HCC incidence. NAFLD pathogenesis is severely influenced by lifestyle and genetic predisposition. Mitochondria are highly dynamic organelles that may adapt in response to environment, genetics and epigenetics in the liver ("mitochondrial plasticity"). Mounting evidence highlights that mitochondrial dysfunction due to loss of mitochondrial flexibility may arise before overt NAFLD, and from the early stages of liver injury. Mitochondrial failure promotes not only hepatocellular damage, but also release signals (mito-DAMPs), which trigger inflammation and fibrosis, generating an adverse microenvironment in which several hepatocytes select anti-apoptotic programs and mutations that may allow survival and proliferation. Furthermore, one of the key events in malignant hepatocytes is represented by the remodeling of glucidic-lipidic metabolism combined with the reprogramming of mitochondrial functions, optimized to deal with energy demand. In sum, this review will discuss how mitochondrial defects may be translated into causative explanations of NAFLD-driven HCC, emphasizing future directions for research and for the development of potential preventive or curative strategies.

Surmounting tumor resistance to metallodrugs by co-loading a metal complex and siRNA in nanoparticles

Copper complexes are promising anticancer agents widely studied to overcome tumor resistance to metal-based anticancer drugs. Nevertheless, copper complexes per se encounter drug resistance from time to time. Adenosine-5'-triphosphate (ATP)-responsive nanoparticles containing a copper complex CTND and B-cell lymphoma 2 (Bcl-2) small interfering RNA (siRNA) were constructed to cope with the resistance of cancer cells to the complex. CTND and siRNA can be released from the nanoparticles in cancer cells upon reacting with intracellular ATP. The resistance of B16F10 melanoma cells to CTND was terminated by silencing the cellular Bcl-2 gene via RNA interference, and the therapeutic efficacy was significantly enhanced. The nanoparticles triggered a cellular autophagy that amplified the apoptotic signals, thus revealing a novel mechanism for antagonizing the resistance of copper complexes. In view of the extensive association of Bcl-2 protein with cancer resistance to chemotherapeutics, this strategy may be universally applicable for overcoming the ubiquitous drug resistance to metallodrugs.