Tumor suppressor p53 restrains cancer cell dissemination by modulating mitochondrial dynamics

Mitochondria: A source of potential biomarkers for non-communicable diseases

Mitochondria, as an endosymbiont of eukaryotic cells, controls multiple cellular activities, including respiration, reactive oxygen species production, fatty acid synthesis, and death. Though the majority of functional mitochondrial proteins are translated through a nucleus-controlled process, very few of them (∼10%) are translated within mitochondria through their own machinery. Germline and somatic mutations in mitochondrial and nuclear DNA significantly impact mitochondrial homeostasis and function. Such modifications disturbing mitochondrial biogenesis, metabolism, or mitophagy eventually resulted in cellular pathophysiology. In this chapter, we discussed the impact of mitochondria and its dysfunction on several non-communicable diseases like cancer, diabetes, neurodegenerative, and cardiovascular problems. Mitochondrial dysfunction and its outcome could be screened by currently available omics-based techniques, flow cytometry, and high-resolution imaging. Such characterization could be evaluated as potential biomarkers to assess the disease burden and prognosis.

HIF1A-dependent overexpression of MTFP1 promotes lung squamous cell carcinoma development by activating the glycolysis pathway

Introduction

Mitochondrial fission process 1 (MTFP1) is an inner mitochondrial membrane (IMM) protein implicated in the development and progression of various tumors, particularly lung squamous cell carcinoma (LUSC). This study aims to provide a more theoretical basis for the treatment of LUSC.

Methods

Through bioinformatics analysis, MTFP1 was identified as a novel target gene of HIF1A. MTFP1 expression in LUSC was examined using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Proteomics Data Commons (PDC) databases. The Kaplan-Meier plotter (KM plotter) database was utilized to evaluate its correlation with patient survival. Western blot and chromatin immunoprecipitation (ChIP) assays were employed to confirm the regulatory relationship between MTFP1 and HIF1A. Additionally, cell proliferation, colony formation, and migration assays were conducted to investigate the mechanism by which MTFP1 enhances LUSC cell proliferation and metastasis.

Results

Our findings revealed that MTFP1 overexpression correlated with poor prognosis in LUSC patients(P < 0.05). Moreover, MTFP1 was closely associated with hypoxia and glycolysis in LUSC (R = 0.203; P < 0.001, R = 0.391; P < 0.001). HIF1A was identified as a positive regulator of MTFP1. Functional enrichment analysis demonstrated that MTFP1 played a role in controlling LUSC cell proliferation. Cell proliferation, colony formation, and migration assays indicated that MTFP1 promoted LUSC cell proliferation and metastasis by activating the glycolytic pathway (P < 0.05).

Conclusions

This study establishes MTFP1 as a novel HIF1A target gene that promotes LUSC growth by activating the glycolytic pathway. Investigating MTFP1 may contribute to the development of effective therapies for LUSC patients, particularly those lacking targeted oncogene therapies.

PTPLAD1 Regulates PHB-Raf Interaction to Orchestrate Epithelial-Mesenchymal and Mitofusion-Fission Transitions in Colorectal Cancer

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide. The poor prognosis of this malignancy is attributed mainly to the persistent activation of cancer signaling for metastasis. Here, we showed that protein tyrosine phosphatase-like A domain containing 1 (PTPLAD1) is down-regulated in highly metastatic CRC cells and negatively associated with poor survival of CRC patients. Systematic analysis reveals that epithelial-to-mesenchymal transition (EMT) and mitochondrial fusion-to-fission (MFT) transition are two critical features for CRC patients with low expression of PTPLAD1. PTPLAD1 overexpression suppresses the metastasis of CRC in vivo and in vitro by inhibiting the Raf/ERK signaling-mediated EMT and mitofission. Mechanically, PTPLAD1 binds with PHB via its middle fragment (141-178 amino acids) and induces dephosphorylation of PHB-Y259 to disrupt the interaction of PHB-Raf, resulting in the inactivation of Raf/ERK signaling. Our results unveil a novel mechanism in which Raf/ERK signaling activated in metastatic CRC induces EMT and mitochondrial fission simultaneously, which can be suppressed by PTPLAD1. This finding may provide a new paradigm for developing more effective treatment strategies for CRC.

p53 contributes to cardiovascular diseases via mitochondria dysfunction: A new paradigm

Cardiovascular diseases (CVDs) are leading causes of global mortality; however, their underlying mechanisms remain unclear. The tumor suppressor factor p53 has been extensively studied for its role in cancer and is also known to play an important role in regulating CVDs. Abnormal p53 expression levels and modifications contribute to the occurrence and development of CVDs. Additionally, mounting evidence underscores the critical involvement of mitochondrial dysfunction in CVDs. Notably, studies indicate that p53 abnormalities directly correlate with mitochondrial dysfunction and may even interact with each other. Encouragingly, small molecule inhibitors targeting p53 have exhibited remarkable effects in animal models of CVDs. Moreover, therapeutic strategies aimed at mitochondrial-related molecules and mitochondrial replacement therapy have demonstrated their advantageous potential. Therefore, targeting p53 or mitochondria holds immense promise as a pioneering therapeutic approach for combating CVDs. In this comprehensive review, we delve into the mechanisms how p53 influences mitochondrial dysfunction, including energy metabolism, mitochondrial oxidative stress, mitochondria-induced apoptosis, mitochondrial autophagy, and mitochondrial dynamics, in various CVDs. Furthermore, we summarize and discuss the potential significance of targeting p53 or mitochondria in the treatment of CVDs.

Tumor suppressor p53 mediates interleukin-6 expression to enable cancer cell evasion of genotoxic stress

The tumor suppressor p53 primarily functions as a mediator of DNA damage-induced cell death, thereby contributing to the efficacy of genotoxic anticancer therapeutics. Here, we show, on the contrary, that cancer cells can employ genotoxic stress-induced p53 to acquire treatment resistance through the production of the pleiotropic cytokine interleukin (IL)-6. Mechanistically, DNA damage, either repairable or irreparable, activates p53 and stimulates Caspase-2-mediated cleavage of its negative regulator mouse double minute 2 (MDM2) creating a positive feedback loop that leads to elevated p53 protein accumulation. p53 transcriptionally controls the major adenosine triphosphate (ATP) release channel pannexin 1 (Panx1), which directs IL-6 induction via a mechanism dependent on the extracellular ATP-activated purinergic P2 receptors as well as their downstream intracellular calcium (iCa2+)/PI3K/Akt/NF-ĸB signaling pathway. Thus, p53 silencing impairs Panx1 and IL-6 expression and renders cancer cells sensitive to genotoxic stress. Moreover, we confirm that IL-6 hampers the effectiveness of genotoxic anticancer agents by mitigating DNA damage, driving the expression of anti-apoptotic Bcl-2 family genes, and maintaining the migratory and invasive properties of cancer cells. Analysis of patient survival and relevant factors in lung cancer and pan-cancer cohorts supports the prognostic and clinical values of Panx1 and IL-6. Notably, IL-6 secreted by cancer cells during genotoxic treatments promotes the polarization of monocytic THP-1-derived macrophages into an alternative (M2-like) phenotype that exhibits impaired anti-survival activities but enhanced pro-metastatic effects on cancer cells as compared to nonpolarized macrophages. Our study reveals the precise mechanism for genotoxic-induced IL-6 and suggests that targeting p53-mediated IL-6 may improve the responsiveness of cancer cells to genotoxic anticancer therapy.

Therapeutic Targeting of Mitochondrial Plasticity and Redox Control to Overcome Cancer Chemoresistance

Significance: Mitochondria are subcellular organelles performing essential metabolic functions contributing to cellular bioenergetics and regulation of cell growth or death. The basic mitochondrial function in fulfilling the need for cell growth and vitality is evidenced whereby cancer cells with depleted mitochondrial DNA (rho zero, p0 cells) no longer form tumors until newly recruited mitochondria are internalized into the rho zero cells. Herein lies the absolute dependency on mitochondria for tumor growth. Hence, mitochondria are key regulators of cell death (by apoptosis, necroptosis, or other forms of cell death) and are, therefore, important targets for anticancer therapy. Recent Advances: Mitochondrial plasticity regulating their state of fusion or fission is key to the chemoresistance properties of cancer cells by promoting pro-survival pathways, enabling the mitochondria to mitigate against the cellular stresses and extreme conditions within the tumor microenvironment caused by chemotherapy, hypoxia, or oxidative stress. Critical Issues: This review discusses many characteristics of mitochondria, the processes and pathways controlling the dynamic changes occurring in the morphology of mitochondria, the roles of reactive oxygen species, and their relationship with mitochondrial fission or fusion. It also examines the relationship of redox to mitophagy when mitochondria become compromised and its effect on cancer cell survival, stemness, and the changes accompanying malignant progression from primary tumors to metastatic disease. Future Directions: A challenging question that arises is whether the changes in mitochondrial dynamics and their regulation can provide opportunities for improving drug targeting during cancer treatment and enhancing survival outcomes. Antioxid. Redox Signal. 39, 591-619.

The Role of Mitochondrial Dynamics and Mitotic Fission in Regulating the Cell Cycle in Cancer and Pulmonary Arterial Hypertension: Implications for Dynamin-Related Protein 1 and Mitofusin2 in Hyperproliferative Diseases

Mitochondria, which generate ATP through aerobic respiration, also have important noncanonical functions. Mitochondria are dynamic organelles, that engage in fission (division), fusion (joining) and translocation. They also regulate intracellular calcium homeostasis, serve as oxygen-sensors, regulate inflammation, participate in cellular and organellar quality control and regulate the cell cycle. Mitochondrial fission is mediated by the large GTPase, dynamin-related protein 1 (Drp1) which, when activated, translocates to the outer mitochondrial membrane (OMM) where it interacts with binding proteins (Fis1, MFF, MiD49 and MiD51). At a site demarcated by the endoplasmic reticulum, fission proteins create a macromolecular ring that divides the organelle. The functional consequence of fission is contextual. Physiological fission in healthy, nonproliferating cells mediates organellar quality control, eliminating dysfunctional portions of the mitochondria via mitophagy. Pathological fission in somatic cells generates reactive oxygen species and triggers cell death. In dividing cells, Drp1-mediated mitotic fission is critical to cell cycle progression, ensuring that daughter cells receive equitable distribution of mitochondria. Mitochondrial fusion is regulated by the large GTPases mitofusin-1 (Mfn1) and mitofusin-2 (Mfn2), which fuse the OMM, and optic atrophy 1 (OPA-1), which fuses the inner mitochondrial membrane. Mitochondrial fusion mediates complementation, an important mitochondrial quality control mechanism. Fusion also favors oxidative metabolism, intracellular calcium homeostasis and inhibits cell proliferation. Mitochondrial lipids, cardiolipin and phosphatidic acid, also regulate fission and fusion, respectively. Here we review the role of mitochondrial dynamics in health and disease and discuss emerging concepts in the field, such as the role of central versus peripheral fission and the potential role of dynamin 2 (DNM2) as a fission mediator. In hyperproliferative diseases, such as pulmonary arterial hypertension and cancer, Drp1 and its binding partners are upregulated and activated, positing mitochondrial fission as an emerging therapeutic target.

Action mechanism of snake venom l-amino acid oxidase and its double-edged sword effect on cancer treatment: Role of pannexin 1-mediated interleukin-6 expression

Snake venom l-amino acid oxidases (svLAAOs) have been recognized as promising candidates for anticancer therapeutics. However, multiple aspects of their catalytic mechanism and the overall responses of cancer cells to these redox enzymes remain ambiguous. Here, we present an analysis of the phylogenetic relationships and active site-related residues among svLAAOs and reveal that the previously proposed critical catalytic residue His 223 is highly conserved in the viperid but not the elapid svLAAO clade. To gain further insight into the action mechanism of the elapid svLAAOs, we purify and characterize the structural, biochemical, and anticancer therapeutic potentials of the Thailand elapid snake Naja kaouthia LAAO (NK-LAAO). We find that NK-LAAO, with Ser 223, exhibits high catalytic activity toward hydrophobic l-amino acid substrates. Moreover, NK-LAAO induces substantial oxidative stress-mediated cytotoxicity with the magnitude relying on both the levels of extracellular hydrogen peroxide (H₂O₂) and intracellular reactive oxygen species (ROS) generated during the enzymatic redox reactions, but not being influenced by the N-linked glycans on its surface. Unexpectedly, we discover a tolerant mechanism deployed by cancer cells to dampen the anticancer activities of NK-LAAO. NK-LAAO treatment amplifies interleukin (IL)-6 expression via the pannexin 1 (Panx1)-directed intracellular calcium (iCa²⁺) signaling pathway to confer adaptive and aggressive phenotypes on cancer cells. Accordingly, IL-6 silencing renders cancer cells vulnerable to NK-LAAO-induced oxidative stress together with abrogating NK-LAAO-stimulated metastatic acquisition. Collectively, our study urges caution when using svLAAOs in cancer treatment and identifies the Panx1/iCa²⁺/IL-6 axis as a therapeutic target for improving the effectiveness of svLAAOs-based anticancer therapies.

DRP1 Inhibition Enhances Venetoclax-Induced Mitochondrial Apoptosis in TP53-Mutated Acute Myeloid Leukemia Cells through BAX/BAK Activation

Although TP53 mutations in acute myeloid leukemia (AML) are associated with poor response to venetoclax, the underlying resistance mechanism remains unclear. Herein, we investigated the functional role of dynamin-related protein 1 (DRP1) in venetoclax sensitivity in AML cells with respect to TP53 mutation status. Effects of DRP1 inhibition on venetoclax-induced cell death were compared in TP53-mutated (THP-1 and Kasumi-1) and TP53 wild-type leukemia cell lines (MOLM-13 and MV4-11), as well as in primary AML cells obtained from patients. Venetoclax induced apoptosis in TP53 wild-type AML cells but had limited effects in TP53-mutated AML cells. DRP1 expression was downregulated in MOLM-13 cells after venetoclax treatment but was unaffected in THP-1 cells. Cotreatment of THP-1 cells with venetoclax and a TP53 activator NSC59984 downregulated DRP1 expression and increased apoptosis. Combination treatment with the DRP1 inhibitor Mdivi-1 and venetoclax significantly increased mitochondria-mediated apoptosis in TP53-mutated AML cells. The combination of Mdivi-1 and venetoclax resulted in noticeable downregulation of MCL-1 and BCL-xL, accompanied by the upregulation of NOXA, PUMA, BAK, and BAX. These findings suggest that DRP1 is functionally associated with venetoclax sensitivity in TP53-mutated AML cells. Targeting DRP1 may represent an effective therapeutic strategy for overcoming venetoclax resistance in TP53-mutated AML.

A comparative assessment of RNF38 and P53 genes expression in the sperm samples obtained from males with normozoospermia and asthenospermia: A case-control study

Background

Infertility is considered as a common problem appears in about 10-12% of couples in their reproductive ages. Ring finger protein 38 (RNF38) gene is a ubiquitin-protein ligase that can regulate Protein 53 (P53) and affect cellular motility.

Objective

Considering the role of P53 on cellular motility and RNF38 on the regulation of P53, the present study aimed to assess the difference between RNF38 and P53 genes expression in normozoospermic and asthenospermic samples as a diagnostic biomarker in males.

Materials and Methods

The present study was conducted among 21 asthenospermicsand 63 healthy individuals. First, the real-time polymerase chain reaction technique was applied to measure the expression level of the P53 and RNF38 genes extracted from sperm samples, and the glyceraldehyde-3phosphate dehydrogenase gene was selected as the reference gene.

Results

An increase and a decrease occurred in the level of P53 and RNF38 genes expressions in asthenospermic and normozoospermic samples, respectively. In addition, a significant difference was observed between increasing P53 gene expression (p < 0.001), reducing RNF38 one, and decreasing sperm motility (p < 0.001) in asthenospermic cells compared to that of normozoospermic ones.

Conclusion

Based on the results, an increase in the expression of the P53 gene and a decrease in the expression of the RNF38 gene had a significant relationship with asthenospermia in men. Therefore, it is expected that an effective step should be adopted to diagnose the asthenospermia expression pattern by using these results.

p53: From Fundamental Biology to Clinical Applications in Cancer

Simple Summary

p53 tumour suppressor gene is the most altered in cancer. Several decades of research have established that it is of pivotal importance in prompting neoplastic phenomena, including cancer initiation and progression. However, it has crucial functions for cellular life. Knowledge and awareness about these multifaceted properties should be part of the cultural background of all scientists. In this review, we describe and discuss the multifaceted roles of p53, from its discovery to clinical applications in cancer therapy.

Abstract

p53 tumour suppressor gene is our major barrier against neoplastic transformation. It is involved in many cellular functions, including cell cycle arrest, senescence, DNA repair, apoptosis, autophagy, cell metabolism, ferroptosis, immune system regulation, generation of reactive oxygen species, mitochondrial function, global regulation of gene expression, miRNAs, etc. Its crucial importance is denounced by the high percentage of amino acid sequence identity between very different species (Homo sapiens, Drosophila melanogaster, Rattus norvegicus, Danio rerio, Canis lupus familiaris, Gekko japonicus). Many of its activities allowed life on Earth (e.g., repair from radiation-induced DNA damage) and directly contribute to its tumour suppressor function. In this review, we provide paramount information on p53, from its discovery, which is an interesting paradigm of science evolution, to potential clinical applications in anti-cancer treatment. The description of the fundamental biology of p53 is enriched by specific information on the structure and function of the protein as well by tumour/host evolutionistic perspectives of its role.