Expanding Roles of the E2F-RB-p53 Pathway in Tumor Suppression

The transcription factor E2F links the RB pathway to the p53 pathway upon loss of function of pRB, thereby playing a pivotal role in the suppression of tumorigenesis. E2F fulfills a major role in cell proliferation by controlling a variety of growth-associated genes. The activity of E2F is controlled by the tumor suppressor pRB, which binds to E2F and actively suppresses target gene expression, thereby restraining cell proliferation. Signaling pathways originating from growth stimulative and growth suppressive signals converge on pRB (the RB pathway) to regulate E2F activity. In most cancers, the function of pRB is compromised by oncogenic mutations, and E2F activity is enhanced, thereby facilitating cell proliferation to promote tumorigenesis. Upon such events, E2F activates the Arf tumor suppressor gene, leading to activation of the tumor suppressor p53 to protect cells from tumorigenesis. ARF inactivates MDM2, which facilitates degradation of p53 through proteasome by ubiquitination (the p53 pathway). P53 suppresses tumorigenesis by inducing cellular senescence or apoptosis. Hence, in almost all cancers, the p53 pathway is also disabled. Here we will introduce the canonical functions of the RB-E2F-p53 pathway first and then the non-classical functions of each component, which may be relevant to cancer biology.

Ferroptosis: Emerging Role in Diseases and Potential Implication of Bioactive Compounds

Ferroptosis is a form of cell death that is distinguished from other types of death for its peculiar characteristics of death regulated by iron accumulation, increase in ROS, and lipid peroxidation. In the past few years, experimental evidence has correlated ferroptosis with various pathological processes including neurodegenerative and cardiovascular diseases. Ferroptosis also is involved in several types of cancer because it has been shown to induce tumor cell death. In particular, the pharmacological induction of ferroptosis, contributing to the inhibition of the proliferative process, provides new ideas for the pharmacological treatment of cancer. Emerging evidence suggests that certain mechanisms including the Xc- system, GPx4, and iron chelators play a key role in the regulation of ferroptosis and can be used to block the progression of many diseases. This review summarizes current knowledge on the mechanism of ferroptosis and the latest advances in its multiple regulatory pathways, underlining ferroptosis' involvement in the diseases. Finally, we focused on several types of ferroptosis inducers and inhibitors, evaluating their impact on the cell death principal targets to provide new perspectives in the treatment of the diseases and a potential pharmacological development of new clinical therapies.

The Role of p53 in Nanoparticle-Based Therapy for Cancer

p53 is arguably one of the most important tumor suppressor genes in humans. Due to the paramount importance of p53 in the onset of cell cycle arrest and apoptosis, the p53 gene is found either silenced or mutated in the vast majority of cancers. Furthermore, activated wild-type p53 exhibits a strong bystander effect, thereby activating apoptosis in surrounding cells without being physically present there. For these reasons, p53-targeted therapy that is designed to restore the function of wild-type p53 in cancer cells seems to be a very appealing therapeutic approach. Systemic delivery of p53-coding DNA or RNA using nanoparticles proved to be feasible both in vitro and in vivo. In fact, one p53-based therapeutic (gendicine) is currently approved for commercial use in China. However, the broad use of p53-based therapy in p53-inactivated cancers is severely restricted by its inadequate efficacy. This review highlights the current state-of-the-art in this area of biomedical research and also discusses novel approaches that may help overcome the shortcomings of p53-targeting nanomedicine.

Gankyrin inhibits ferroptosis through the p53/SLC7A11/GPX4 axis in triple-negative breast cancer cells

Gankyrin is found in high levels in triple-negative breast cancer (TNBC) and has been established to form a complex with the E3 ubiquitin ligase MDM2 and p53, resulting in the degradation of p53 in hepatocarcinoma cells. Therefore, this study sought to determine whether gankyrin could inhibit ferroptosis through this mechanism in TNBC cells. The expression of gankyrin was investigated in relation to the prognosis of TNBC using bioinformatics. Co-immunoprecipitation and GST pull-down assays were then conducted to determine the presence of a gankyrin and MDM2 complex. RT-qPCR and immunoblotting were used to examine molecules related to ferroptosis, such as gankyrin, p53, MDM2, SLC7A11, and GPX4. Additionally, cell death was evaluated using flow cytometry detection of 7-AAD and a lactate dehydrogenase release assay, as well as lipid peroxide C11-BODIPY. Results showed that the expression of gankyrin is significantly higher in TNBC tissues and cell lines, and is associated with a poor prognosis for patients. Subsequent studies revealed that inhibiting gankyrin activity triggered ferroptosis in TNBC cells. Additionally, silencing gankyrin caused an increase in the expression of the p53 protein, without altering its mRNA expression. Co-immunoprecipitation and GST pull-down experiments indicated that gankyrin and MDM2 form a complex. In mouse embryonic fibroblasts lacking both MDM2 and p53, this gankyrin/MDM2 complex was observed to ubiquitinate p53, thus raising the expression of molecules inhibited by ferroptosis, such as SLC7A11 and GPX4. Furthermore, silencing gankyrin in TNBC cells disrupted the formation of the gankyrin/MDM2 complex, hindered the degradation of p53, increased SLC7A11 expression, impeded cysteine uptake, and decreased GPX4 production. Our findings suggest that TNBC cells are able to prevent cell ferroptosis through the gankyrin/p53/SLC7A11/GPX4 signaling pathway, indicating that gankyrin may be a useful biomarker for predicting TNBC prognosis or a potential therapeutic target.

ALOX5 deficiency contributes to bladder cancer progression by mediating ferroptosis escape

Ferroptosis is an iron-dependent form of regulated cell death driven by the lethal lipid peroxides. Previous studies have demonstrated that inducing ferroptosis holds great potential in cancer therapy, especially for patients with traditional therapy failure. However, cancer cells can acquire ferroptosis evasion during progression. To date, the therapeutic potential of inducing ferroptosis in bladder cancer (BCa) remains unclear, and whether a ferroptosis escape mechanism exists in BCa needs further investigation. This study verified that low pathological stage BCa cells were highly sensitive to RSL3-induced ferroptosis, whereas high pathological stage BCa cells exhibited obviously ferroptosis resistance. RNA-seq, RNAi-mediated loss-of-function, and CRISPR/Cas9 experiments demonstrated that ALOX5 deficiency was the crucial factor of BCa resistance to ferroptosis in vitro and in vivo. Mechanistically, we found that ALOX5 deficiency was regulated by EGR1 at the transcriptional level. Clinically, ALOX5 expression was decreased in BCa tissues, and its low expression was associated with poor survival. Collectively, this study uncovers a novel mechanism for BCa ferroptosis escape and proposes that ALOX5 may be a valuable therapeutic target and prognostic biomarker in BCa treatment.

Ferroptosis: an important player in the inflammatory response in diabetic nephropathy

Diabetic nephropathy (DN) is a chronic inflammatory disease that affects millions of diabetic patients worldwide. The key to treating of DN is early diagnosis and prevention. Once the patient enters the clinical proteinuria stage, renal damage is difficult to reverse. Therefore, developing early treatment methods is critical. DN pathogenesis results from various factors, among which the immune response and inflammation play major roles. Ferroptosis is a newly discovered type of programmed cell death characterized by iron-dependent lipid peroxidation and excessive ROS production. Recent studies have demonstrated that inflammation activation is closely related to the occurrence and development of ferroptosis. Moreover, hyperglycemia induces iron overload, lipid peroxidation, oxidative stress, inflammation, and renal fibrosis, all of which are related to DN pathogenesis, indicating that ferroptosis plays a key role in the development of DN. Therefore, this review focuses on the regulatory mechanisms of ferroptosis, and the mutual regulatory processes involved in the occurrence and development of DN and inflammation. By discussing and analyzing the relationship between ferroptosis and inflammation in the occurrence and development of DN, we can deepen our understanding of DN pathogenesis and develop new therapeutics targeting ferroptosis or inflammation-related regulatory mechanisms for patients with DN.

Emerging role and therapeutic implications of p53 in intervertebral disc degeneration

Lower back pain (LBP) is a common degenerative musculoskeletal disease that imposes a huge economic burden on both individuals and society. With the aggravation of social aging, the incidence of LBP has increased globally. Intervertebral disc degeneration (IDD) is the primary cause of LBP. Currently, IDD treatment strategies include physiotherapy, medication, and surgery; however, none can address the root cause by ending the degeneration of intervertebral discs (IVDs). However, in recent years, targeted therapy based on specific molecules has brought hope for treating IDD. The tumor suppressor gene p53 produces a transcription factor that regulates cell metabolism and survival. Recently, p53 was shown to play an important role in maintaining IVD microenvironment homeostasis by regulating IVD cell senescence, apoptosis, and metabolism by activating downstream target genes. This study reviews research progress regarding the potential role of p53 in IDD and discusses the challenges of targeting p53 in the treatment of IDD. This review will help to elucidate the pathogenesis of IDD and provide insights for the future development of precision treatments.

Molecular Mechanisms of Ferroptosis and Its Role in Viral Pathogenesis

Ferroptosis is a novelty form of regulated cell death, and it is mainly characterized by iron accumulation and lipid peroxidation in the cells. Its underlying mechanism is related to the amino acid, iron, and lipid metabolisms. During viral infection, pathogenic microorganisms have evolved to interfere with ferroptosis, and ferroptosis is often manipulated by viruses to regulate host cell servicing for viral reproduction. Therefore, this review provides a comprehensive overview of the mechanisms underlying ferroptosis, elucidates the intricate signaling pathways involved, and explores the pivotal role of ferroptosis in the pathogenesis of viral infections. By enhancing our understanding of ferroptosis, novel therapeutic strategies can be devised to effectively prevent and treat diseases associated with this process. Furthermore, unraveling the developmental mechanisms through which viral infections exploit ferroptosis will facilitate development of innovative antiviral agents.

Atypical genotoxicity of carcinogenic nickel(II): Linkage to dNTP biosynthesis, DNA-incorporated rNMPs, and impaired repair of TOP1-DNA crosslinks

Cancer is a genetic disease requiring multiple mutations for its development. However, many carcinogens are DNA-unreactive and nonmutagenic and consequently described as nongenotoxic. One of such carcinogens is nickel, a global environmental pollutant abundantly emitted by burning of coal. We investigated activation of DNA damage responses by Ni and identified this metal as a replication stressor. Genotoxic stress markers indicated the accumulation of ssDNA and stalled replication forks, and Ni-treated cells were dependent on ATR for suppression of DNA damage and long-term survival. Replication stress by Ni resulted from destabilization of RRM1 and RRM2 subunits of ribonucleotide reductase and the resulting deficiency in dNTPs. Ni also increased DNA incorporation of rNMPs (detected by a specific fluorescent assay) and strongly enhanced their genotoxicity as a result of repressed repair of TOP1-DNA protein crosslinks (TOP1-DPC). The DPC-trap assay found severely impaired SUMOylation and K48-polyubiquitination of DNA-crosslinked TOP1 due to downregulation of specific enzymes. Our findings identified Ni as the human carcinogen inducing genome instability via DNA-embedded ribonucleotides and accumulation of TOP1-DPC which are carcinogenic abnormalities with poor detectability by the standard mutagenicity tests. The discovered mechanisms for Ni could also play a role in genotoxicity of other protein-reactive carcinogens.

Deeper insight into ferroptosis: association with Alzheimer's, Parkinson's disease, and brain tumors and their possible treatment by nanomaterials induced ferroptosis

Ferroptosis is an emerging and novel type of iron-dependent programmed cell death which is mainly caused by the excessive deposition of free intracellular iron in the brain cells. This deposited free iron exerts a ferroptosis pathway, resulting in lipid peroxidation (LiPr). There are mainly three ferroptosis pathways viz. iron metabolism-mediated cysteine/glutamate, and LiPr-mediated. Iron is required by the brain as a redox metal for several physiological activities. Due to the iron homeostasis balance disruption, the brain gets adversely affected which further causes neurodegenerative diseases (NDDs) like Parkinson's and Alzheimer's disease, strokes, and brain tumors like glioblastoma (GBS), and glioma. Nanotechnology has played an important role in the prevention and treatment of these NDDs. A synergistic effect of nanomaterials and ferroptosis could prove to be an effective and efficient approach in the field of nanomedicine. In the current review, the authors have highlighted all the latest research in the field of ferroptosis, specifically emphasizing on the role of major molecular key players and various mechanisms involved in the ferroptosis pathway. Moreover, here the authors have also addressed the correlation of ferroptosis with the pathophysiology of NDDs and theragnostic effect of ferroptosis and nanomaterials for the prevention and treatment of NDDs.

The Clinical Significance of MicroRNAs in Colorectal Cancer Signaling Pathways: A Review

Colorectal carcinoma (colon and rectum) is currently considered among the most prevalent malignancies of Western societies. The pathogenesis and etiological mechanisms underlying colorectal cancer (CRC) development remain complex and heterogeneous. The homeostasis and function of normal human intestinal cells is highly regulated by microRNAs. Therefore, it is not surprising that mutations and inactivation of these molecules appear to be linked with progression of colorectal tumors. Recent studies have reported significant alterations of microRNA expression in adenomas and CRCs compared with adjacent normal tissues. This observed deviation has been proposed to correlate with the progression and survival of disease as well as with choice of optimal treatment and drug resistance. MicroRNAs can adopt either oncogenic or tumor-suppressive roles during regulation of pathways that drive carcinogenesis. Typically, oncogenic microRNAs termed oncomirs, target and silence endogenous tumor-suppressor genes. On the other hand, tumor-suppressive microRNAs are critical in downregulating genes associated with cell growth and malignant capabilities. By extensively evaluating robust studies, we have emphasized and distinguished a discrete set of microRNAs that can modulate tumor progression by silencing specific driver genes crucial in signaling pathways including Wnt/b-catenin, epidermal growth factor receptor, P53, mismatch repair DNA repair, and transforming-growth factor beta.

Ferroptosis Signaling Pathways: Alzheimer's Disease

The involvements of iron metabolism, lipid peroxidation, and oxidative stress in Alzheimer's disease (AD) development have recently received a lot of attention. We also observe that these pathogenic occurrences play a key role in regulating ferroptosis, a unique regulatory cell death that is iron-dependent, oxidative, and non-apoptotic. Iron is a crucial component that makes up a subunit of the oxidase responsible for lipid peroxidation. A family of non-heme iron enzymes known as lipoxygenases (LOXs) can cause ferroptosis by oxidising polyunsaturated fatty acids in cellular membranes (PUFAs). Toxic lipid hydroperoxides are produced in large part by the iron in LOX active sites. Deferoxamine and deferiprone, two iron chelators, could also treat ferroptosis by eliminating the crucial catalytic iron from LOXs. Phospholipids containing polyunsaturated fatty acids are the main substrates of lipid peroxidation in ferroptosis, which is favourably controlled by enzymes like ACSL4, LPCAT3, ALOXs, or POR. Selective stimulation of autophagic degradation pathways leads to an increase in iron accumulation and lipid peroxidation, which promotes ferroptosis. We highlighted recent advancements in our understanding of ferroptosis signaling routes in this study. One form of regulated necrotic cell death known as ferroptosis has been linked to a number of diseases, including cancer, neurological disorders, and ischemia/reperfusion injury. Cerebrospinal fluid (CSF) ferritin may be a good indicator of the amount of iron in the brain because it is the main protein that stores iron.

Differential tissue expression of sex steroid-synthesizing enzyme CYP11A1 in male Tibetan sheep (Ovis aries)

Steroid metabolism is a fundament to testicular development and function. The cytochrome P450, family 11, subfamily A, polypeptide 1 (CYP11A1) is a key rate-limiting enzyme for catalyzing the conversion of cholesterol to pregnenolone. However, despite its importance, what expression and roles of CYP11A1 possesses and how it regulates the testicular development and spermatogenesis in Tibetan sheep remains largely unknown. Based on this, we evaluated the expression and localization patterns of CYP11A1 in testes and epididymides of Tibetan sheep at three developmental stages (three-month-old, pre-puberty; one-year-old, sexual maturity and three-year-old, adult) by quantitative real-time PCR (qPCR), western blot and immunofluorescence. The results showed that CYP11A1 mRNA and protein were expressed in testes and epididymides throughout the development stages and obviously more intense in one- and three-year-old groups than three-month-old group (except for the caput epididymidis). Immunofluorescence assay showed that the CYP11A1 protein was mainly located in Leydig cells and epididymal epithelial cells. In addition, positive signals of CYP11A1 protein were observed in germ cells, epididymal connective tissue and sperms stored in the epididymal lumen. Collectively, these results suggested that the CYP11A1 gene might be mainly involved in regulating spermatogenesis and androgen synthesis in developmental Tibetan sheep testis and epididymis.

Peptide fractions from Sacha inchi induced apoptosis in HepG2 cells via P53 activation and a mitochondria-mediated pathway

BACKGROUND

Sacha inchi is known for its high protein content and medicinal properties. Bioactive peptides have been reported to have therapeutic potential in various human diseases. However, there is a lack of research evaluating the pharmacological value of peptides derived from Sacha inchi. Therefore, this study aimed to investigate the anti-hepatoma effect of Sacha inchi peptides (SPs) and their underlying mechanism.

RESULTS

The study found that treatment with SPs significantly reduced the proliferation of HepG2 cells by inducing apoptosis and arresting the cell cycle at the G0/G1 phase. SPs also induced HepG2 cell apoptosis by increasing the levels of proteins such as Bax, Caspase-3 and P53. The study identified nine novel peptides in SPs, of which LLEPDVR, ALVEKAKAS and TGDGSLRPY exhibited higher cell proliferative inhibition rates compared to other peptides.

CONCLUSION

The findings of this study suggest that Sacha inchi peptides have potential pharmacological effects in the treatment of liver cancer. SPs effectively suppress the cell cycle and facilitate cell apoptosis, indicating their anti-hepatoma effect. The novel peptides identified in SPs may have therapeutic value for liver cancer treatment. © 2023 Society of Chemical Industry.

Squalene epoxidase promotes breast cancer progression by regulating CCNB1 protein stability

BACKGROUND

Breast cancer (BC) is a prevalent malignancy affecting women, characterized by a substantial occurrence rate. Squalene epoxidase (SQLE) is a crucial regulator of ferroptosis and has been associated with promoting cell growth and invasion in different types of human cancers. This study aimed to investigate the functional significance of SQLE in BC and elucidate the underlying molecular mechanisms involved.

METHODS

SQLE expression levels in BC tissues were evaluated using quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry. Cell viability, invasion, migration, and cell cycle distribution were assessed using a combination of assays, including the Cell Counting Kit-8, EdU, colony formation, Transwell, and wound healing assays and flow cytometry analysis. Measurement of intracellular reactive oxygen species (ROS), malondialdehyde assay, and glutathione assay were utilized to investigate ferroptosis. Furthermore, co-immunoprecipitation and immunofluorescence assays were conducted to explore the correlation between SQLE and CCNB1. The in vivo tumor growth was evaluated by conducting a xenograft tumorigenicity assay to investigate the impact of SQLE.

RESULTS

SQLE expression was significantly increased in BC, and higher SQLE expression levels were significantly associated with an unfavorable prognosis. In vitro functional assays revealed that the overexpression of SQLE markedly enhanced the proliferation, migration, and invasion capacities of BC cells. Furthermore, SQLE overexpression facilitated tumor growth in nude mice. Mechanistically, SQLE alleviated the ubiquitination modification of CCNB1, leading to enhanced stability of the CCNB1 protein and decreased intracellular ROS levels. Ultimately, this inhibited ferroptosis and facilitated the progression of BC. Our findings have provided insights into a crucial pathway by which elevated SQLE expression confers protection to BC cells against ferroptosis, thus promoting cancer progression. SQLE may serve as a novel oncological marker and a potential therapeutic target for BC progression.

CONCLUSIONS

In conclusion, this study provides evidence that SQLE plays a regulatory role in BC progression by modulating CCNB1 and ferroptosis. These findings offer valuable insights into the role of SQLE in the pathogenesis of BC and demonstrate its potential as a therapeutic target for treating BC.

Melatonin and ferroptosis: Mechanisms and therapeutic implications

Ferroptosis, a regulated form of cell death, is characterized by iron-dependent lipid peroxidation leading to oxidative damage to cell membranes. Cell sensitivity to ferroptosis is influenced by factors such as iron overload, lipid metabolism, and the regulation of the antioxidant system. Melatonin, with its demonstrated capacity to chelate iron, modulate iron metabolism proteins, regulate lipid peroxidation, and regulate antioxidant systems, has promise as a potential therapeutic agent in mediating ferroptosis. The availability of approved drugs targeting ferroptosis is limited; therefore, melatonin is a candidate for broad application due to its safety and efficacy in attenuating ferroptosis in noncancerous diseases. Melatonin has been demonstrated to attenuate ferroptosis in cellular and animal models of noncancerous diseases, showcasing effectiveness in organs such as the heart, brain, lung, liver, kidney, and bone. This review outlines the molecular mechanisms of ferroptosis, investigates melatonin's potential effects on ferroptosis, and discusses melatonin's therapeutic potential as a promising intervention against diseases associated with ferroptosis. Through this discourse, we aim to lay a strong foundation for developing melatonin as a therapeutic strategy to modulate ferroptosis in a variety of disease contexts.

Ferroptosis in cardiac hypertrophy and heart failure

Heart failure has become a public health problem that we cannot avoid choosing to face in today's context. In the case of heart failure, pathological cardiac hypertrophy plays a major role because of its condition of absolute increase in ventricular mass under various stresses. Ferroptosis, it could be defined as regulatory mechanisms that regulate cell death in the absence of apoptosis in iron-dependent cells. This paper introduces various new research findings on the use of different regulatory mechanisms of cellular ferroptosis for the treatment of heart failure and cardiac hypertrophy, providing new therapeutic targets and research directions for clinical treatment. The role and mechanism of ferroptosis in the field of heart failure has been increasingly demonstrated, and the relationship between cardiac hypertrophy, which is one of the causes of heart failure, is also an area of research that we should focus on. In addition, the latest applications and progress of inducers and inhibitors of ferroptosis are reported in this paper, updating the breakthroughs in their fields.

Exploring the role of lncrna neat1 knockdown in regulating apoptosis across multiple cancer types: A review

Long non-coding RNAs (lncRNAs) have emerged as pivotal regulators of gene expression, contributing significantly to a diverse range of cellular processes, including apoptosis. One such lncRNA is NEAT1, which is elevated in several types of cancer and aid in cancer growth. However, recent studies have also demonstrated that the knockdown of NEAT1 can inhibit cancer cells proliferation, movement, and infiltration while enhancing apoptosis. This article explores the function of lncRNA NEAT1 knockdown in regulating apoptosis across multiple cancer types. We explore the existing understanding of NEAT1's involvement in the progression of malignant conditions, including its structure and functions. Additionally, we investigate the molecular mechanisms by which NEAT1 modulates the cell cycle, cellular proliferation, apoptosis, movement, and infiltration in diverse cancer types, including acute myeloid leukemia, breast cancer, cervical cancer, colorectal cancer, esophageal squamous cell carcinoma, glioma, non-small cell lung cancer, ovarian cancer, prostate cancer, and retinoblastoma. Furthermore, we review the recent studies investigating the therapeutic potential of NEAT1 knockdown in cancer treatment. Targeting the lncRNA NEAT1 presents a promising therapeutic approach for treating cancer. It has shown the ability to suppress cancer cell proliferation, migration, and invasion while promoting apoptosis in various cancer types.

Tumor cell-derived exosomes mediating hsa_circ_0001739/lncRNA AC159540.1 facilitate liver metastasis in colorectal cancer

BACKGROUND

The current study probed into how tumor cell-derived exosomes (Exos) mediated hsa_circ_0001739/lncRNA AC159540.1 to manipulate microRNA (miR)-218-5p/FTO-N6-methyladenosine (m6A)/MYC signal axis in liver metastasis in colorectal cancer (CRC).

METHODS

hsa_circ_0001739 and lncRNA AC159540.1 were identified as the upstream regulator of miR-218-5p using ENCORI and LncBase databases. Expression patterns of miR-218-5p, hsa_circ_0001739, lncRNA AC159540.1, FTO, and MYC were detected, accompanied by loss-and-gain-of function assays to examine their effects on CRC cell biological functions. SW480 cells-derived Exos were purified, followed by in vitro studies to uncover the effect of hsa_circ_0001739/lncRNA AC159540.

RESULTS

miR-218-5p was downregulated while hsa_circ_0001739/lncRNA AC159540.1 was upregulated in CRC tissues and cells. Silencing of hsa_circ_0001739/lncRNA AC159540.1 restrained the malignant phenotypes of CRC cells. Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 competitively inhibited miR-218-5p to elevate FTO and MYC. The inducing role of Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 in CRC was also validated in vivo.

CONCLUSION

Conclusively, Exos-mediated circ_0001739/lncRNA AC159540.1 regulatory network is critical for CRC, offering a theoretical basis for CRC treatment.

Molecular characterization of the CXCR4 / CXCR7 axis in germ cell tumors and its targetability using nanobody-drug-conjugates

Being stimulated by the chemokine CXCL12, the CXCR4 / CXCR7 cascade is involved in tumor proliferation, migration, and metastasis. The interaction between CXCL12, secreted by cells from the microenvironment, and its receptors is complex and has been ascribed to promote chemotherapy resistance. However, the role of this signaling axis and its targetability in germ cell tumors (GCT) is not fully understood. Thus, this study investigated the therapeutic efficacy of a nanobody-drug-conjugate targeting CXCR4 (CXCR4-NDC) and functionally characterized this signaling pathway in GCT using small molecule inhibitors and nanobodies. As shown by diminished cell viability, enhanced apoptosis induction, and detection of mitotic catastrophes, we confirmed the cytotoxic efficacy of the CXCR4-NDC in CXCR4+-GCT cells (i.e. seminoma and yolk-sac tumor), while non-malignant CXCR4--fibroblasts, remained largely unaffected. Stimulation of CXCR4+ / CXCR7+-GCT cells with CXCL12 resulted in an enhanced proliferative and migratory capacity, while this effect could be reverted using CXCR4 inhibitors or a CXCR7-nanobody. Molecularly, the CXCR4 / CXCR7-signaling cascade could be activated independently of MAPK (ERK1 / 2)-phosphorylation. Although, in CXCR4- / CXCR7--embryonal carcinoma cells, CXCR7-expression was re-induced upon inhibition of ERK1 / 2-signaling. This study identified a nanobody-drug-conjugate targeting CXCR4 as a putative therapeutic option for GCT, i.e. seminoma and yolk-sac tumors. Furthermore, this study shed light on the functional role of the CXCR4 / CXCR7 / CXCL12-signaling cascade in GCT, demonstrating an important influence on proliferation and migration.

Highly Similar Tetramerization Domains from the p53 Protein of Different Mammalian Species Possess Varying Biophysical, Functional and Structural Properties

The p53 protein is a transcriptional regulatory factor and many of its functions require that it forms a tetrameric structure. Although the tetramerization domain of mammalian p53 proteins (p53TD) share significant sequence similarities, it was recently shown that the tree shrew p53TD is considerably more thermostable than the human p53TD. To determine whether other mammalian species display differences in this domain, we used biophysical, functional, and structural studies to compare the properties of the p53TDs from six mammalian model organisms (human, tree shrew, guinea pig, Chinese hamster, sheep, and opossum). The results indicate that the p53TD from the opossum and tree shrew are significantly more stable than the human p53TD, and there is a correlation between the thermostability of the p53TDs and their ability to activate transcription. Structural analysis of the tree shrew and opossum p53TDs indicated that amino acid substitutions within two distinct regions of their p53TDs can dramatically alter hydrophobic packing of the tetramer, and in particular substitutions at positions corresponding to F341 and Q354 of the human p53TD. Together, the results suggest that subtle changes in the sequence of the p53TD can dramatically alter the stability, and potentially lead to important changes in the functional activity, of the p53 protein.

Spontaneous p53 activation in middle-aged C57BL/6 mice mitigates the lifespan-extending adaptive response induced by low-dose ionizing radiation

Understanding the biological effects of low-dose (<100 mGy) ionizing radiation (LDR) is technically challenging. We investigated age-dependent LDR effects using adaptive response experiments in young (7-to 12-week-old) and middle-aged (40-to 62-week-old) C57BL/6 mice. Compared with 3 Gy irradiation, 0.02 Gy preirradiation followed by 3 Gy irradiation prolonged life in young mice but not middle-aged mice. Preirradiation also suppressed irradiation-induced 53BP1 repair foci in the small intestines, splenic apoptosis, and p53 activity in young mice but not middle-aged mice. Young p53+/- C57BL/6 mice did not show these adaptive responses, indicating that insufficient p53 function in young mice mitigated the adaptive responses. Interestingly, p53 activation in middle-aged mice spontaneously became approximately 4.5-fold greater than that in young mice, possibly masking LDR stresses. Furthermore, adaptive responses in young mice, but not in middle-aged mice, suppressed some senescence-associated secretory phenotype (SASP) factors (IL-6, CCL2, CCL5, CXCL1). Thus, LDR-induced adaptive responses associated with specific SASP factors may be attenuated by a combination of reduced DNA damage sensor/transducer function and chronic p53 activation in middle-aged mice.

Data Mining Suggests That CXCL14 Gene Silencing in Colon Cancer Is Due to Promoter Methylation

CXCL14 is one of the most evolutionarily conserved members of the chemokine family and is constitutionally expressed in multiple organs, suggesting that it is involved in the homeostasis maintenance of the system. CXCL14 is highly expressed in colon epithelial cells and shows obvious gene silencing in clinical colon cancer samples, suggesting that its silencing is related to the immune escape of cancer cells. In this paper, we analyzed the expression profiles of multiple human clinical colon cancer datasets and mouse colon cancer models to reveal the variation trend of CXCL14 expression during colitis, colon polyps, primary colon cancer, and liver metastases. The relationship between CXCL14 gene silencing and promoter hypermethylation was revealed through the colorectal carcinoma methylation database. The results suggest that CXCL14 is a tumor suppressor gene in colorectal carcinoma which is activated first and then silenced during the process of tumor occurrence and deterioration. Promoter hypermethylation is the main cause of CXCL14 silencing. The methylation level of CXCL14 is correlated with the anatomic site of tumor occurrence, positively correlated with patient age, and associated with prognosis. Reversing the hypermethylation of CXCL14 may be an epigenetic therapy for colon cancer.

Cooperatively inhibition effect of miR-143-5p and miR-145-5p in tumorigenesis of glioblastoma cells through modulating AKT signaling pathway

Introduction

As the most common aggressive primary brain tumor, glioblastoma is inevitably a recurrent malignancy whose patients' prognosis is poor. miR-143 and miR-145, as tumor suppressor miRNAs, are downregulated through tumorigenesis of multiple human cancers, including glioblastoma. These two miRNAs regulate numerous cellular processes, such as proliferation and migration. This research was intended to explore the simultaneous replacement effect of miR-143, and miR-145 on in vitro tumorgenicity of U87 glioblastoma cells.

Methods

U87 cells were cultured, and transfected with miR-143-5p and miR-145-5p. Afterward, the changes in cell viability, and apoptosis induction were determined by MTT assay and Annexin V/PI staining. The accumulation of cells at the cell cycle phases was assessed using the flow cytometry. Wound healing and colony formation assays were performed to study cell migration. qRT-PCR and western blot techniques were utilized to quantify gene expression levels.

Results

Our results showed that miR-143-5p and 145-5p exogenous upregulation cooperatively diminished cell viability, and enhanced U-87 cell apoptosis by modulating Caspase-3/8/9, Bax, and Bcl-2 protein expression. The combination therapy increased accumulation of cells at the sub-G1 phase by modulating CDK1, Cyclin D1, and P53 protein expression. miR-143/145-5p significantly decreased cell migration, and reduced colony formation ability by the downregulation of c-Myc and CD44 gene expression. Furthermore, the results showed the combination therapy of these miRNAs could remarkably downregulate phosphorylated-AKT expression levels.

Conclusion

In conclusion, miR-143 and miR-145 were indicated to show cooperative anti- cancer effects on glioblastoma cells via modulating AKT signaling as a new therapeutic approach.

Jun-APOE-LRP1 axis promotes tumor metastasis in colorectal cancer

Apolipoprotein E (apoE) has previously been reported to play vital roles in tumor progression. However, the impact of apoE on colorectal cancer (CRC) metastasis remains largely unexplored. This study aimed to investigate the role of apoE in CRC metastasis and to identify the transcription factor and receptor of apoE involved in regulation of CRC metastasis. Bioinformatic analyses were conducted to examine the expression pattern and prognosis of apolipoproteins. APOE-overexpressing cell lines were utilized to explore the effects of apoE on proliferation, migration and invasion of CRC cells. Additionally, the transcription factor and receptor of apoE were screened via bioinformatics, and further validated through knockdown experiments. We discovered that the mRNA levels of APOC1, APOC2, APOD and APOE were higher in lymphatic invasion group, and a higher apoE level indicated poorer overall survival and progression-free interval. In vitro studies demonstrated that APOE-overexpression did not affect proliferation but promoted the migration and invasion of CRC cells. We also reported that APOE-expression was modulated by the transcription factor Jun by activating the proximal promoter region of APOE, and APOE-overexpression reversed the metastasis suppression of JUN knockdown. Furthermore, bioinformatics analysis suggested an interaction between apoE and low-density lipoprotein receptor-related protein 1 (LRP1). LRP1 was highly expressed in both the lymphatic invasion group and the APOEHigh group. Additionally, we found that APOE-overexpression upregulated LRP1 protein levels, and LRP1 knockdown attenuated the metastasis-promoting function of APOE. Overall, our study suggests that the Jun-APOE-LRP1 axis contributes to tumor metastasis in CRC.

Prospects of microRNAs as therapeutic biomarkers in non-small cell lung cancer

Lung Cancer, the second most common cancer worldwide, remains the leading cause of cancer-related deaths, contemporarily. More than 85% of identified lung cancer cases are comprised of non-small-cell lung carcinoma (NSCLC). Despite the best advancements in the realm of NSCLC therapy, the five-year survival period of NSCLC patients remains unchanged. Underlying complex molecular heterogeneity, delay in early detection resulting in progression of the disease to its advanced stage and acquired resistance of NSCLC cells during therapy have posed additional challenges for circumventing the discrepancies in treatment strategy. microRNAs (miRNAs) are a class of non-coding RNAs, identified as molecules playing an indispensable role in tumorigenesis & progression and metastasis of several cancers, including NSCLC, either by possessing tumor suppressor or by oncogenic functions. As observed across several studies, miRNA dysregulation has been recognised as a causative mechanism behind NSCLC tumorigenesis. In this review, we discuss the role of miRNAs in NSCLC tumor progression caused by their dysregulation, thereby stating their potential therapeutic application in NSCLC as therapeutic biomarkers. We have also highlighted the recent findings of some of the most widely studied tumor suppressor (miR-486, miR-7 miR-34), and oncogene miRNAs (miR-21, miR-224, miR-135b) that can be further explored for its therapeutic potentialities in the management of NSCLC.

A reactive species reactions module for integration into genome-scale metabolic models for improved insights: Application to cancer

Reactive species (RS) play significant roles in many disease contexts. Despite their crucial roles in diseases including cancer, the RS are not adequately modeled in the genome-scale metabolic (GSM) models, which are used to understand cell metabolism in disease contexts. We have developed a scalable RS reactions module that can be integrated with any Recon 3D-derived human metabolic model, or after fine-tuning, with any metabolic model. With RS-integration, the GSM models of three cancers (basal-like triple negative breast cancer (TNBC), high grade serous ovarian carcinoma (HGSOC) and colorectal cancer (CRC)) built from Recon 3D, precisely highlighted the increases/decreases in fluxes (dysregulation) occurring in important pathways of these cancers. These dysregulations were not prominent in the standard cancer models without the RS module. Further, the results from these RS-integrated cancer GSM models suggest the following decreasing order in the ease of ferroptosis-targeting to treat the cancers: TNBC > HGSOC > CRC.

Low glucose metabolite 3-phosphoglycerate switches PHGDH from serine synthesis to p53 activation to control cell fate

Glycolytic intermediary metabolites such as fructose-1,6-bisphosphate can serve as signals, controlling metabolic states beyond energy metabolism. However, whether glycolytic metabolites also play a role in controlling cell fate remains unexplored. Here, we find that low levels of glycolytic metabolite 3-phosphoglycerate (3-PGA) can switch phosphoglycerate dehydrogenase (PHGDH) from cataplerosis serine synthesis to pro-apoptotic activation of p53. PHGDH is a p53-binding protein, and when unoccupied by 3-PGA interacts with the scaffold protein AXIN in complex with the kinase HIPK2, both of which are also p53-binding proteins. This leads to the formation of a multivalent p53-binding complex that allows HIPK2 to specifically phosphorylate p53-Ser46 and thereby promote apoptosis. Furthermore, we show that PHGDH mutants (R135W and V261M) that are constitutively bound to 3-PGA abolish p53 activation even under low glucose conditions, while the mutants (T57A and T78A) unable to bind 3-PGA cause constitutive p53 activation and apoptosis in hepatocellular carcinoma (HCC) cells, even in the presence of high glucose. In vivo, PHGDH-T57A induces apoptosis and inhibits the growth of diethylnitrosamine-induced mouse HCC, whereas PHGDH-R135W prevents apoptosis and promotes HCC growth, and knockout of Trp53 abolishes these effects above. Importantly, caloric restriction that lowers whole-body glucose levels can impede HCC growth dependent on PHGDH. Together, these results unveil a mechanism by which glucose availability autonomously controls p53 activity, providing a new paradigm of cell fate control by metabolic substrate availability.

Long non-coding RNA NBR2 suppresses the progression of colorectal cancer by downregulating miR-19a to regulate M2 macrophage polarization

Colorectal cancer (CRC) is a malignant tumor of the gastrointestinal tract that significantly impacts the health of patients and lacks promising methods of diagnosis. Tumor-associated macrophages (TAMs) are involved in CRC progression, and their function is regulated by long non-coding RNAs (lncRNAs). The lncRNA NBR2 was recently reported as an oncogene, whose function in CRC remains uncertain. The present study aimed to investigate the biological function of lncRNA NBR2 in the progression of CRC and its underlying molecular mechanisms. Ten pairs of clinical CRC and para-carcinoma tissues were collected to determine the expression levels of lncRNA NBR2 and miR-19a, and the polarization state of TAMs. Quantitative reverse transcriptase-polymerase chain reaction was used to evaluate the expression of miR-19a, and western blotting was used to determine the expression levels of tumor necrosis factor-α, human leukocyte antigen-DR, arginase-1, CD163, CD206, interleukin-4, AMP-activated protein kinase (AMPK), p-AMPK, hypoxia-inducible factor-1α (HIF-1α), protein kinase B (AKT), p-AKT, mechanistic target of rapamycin (mTOR), and p-mTOR in TAMs. The proliferative ability of HCT-116 cells was detected using the CCK8 assay, and the migratory ability of HCT-116 cells was evaluated using the Transwell assay. The interaction between lncRNA NBR2 and miR-19a was determined using the luciferase assay. The lncRNA NBR2 was downregulated and miR-19a was highly expressed in CRC cells, accompanied by a high M2 polarization. Downregulated miR-19a promoted M1 polarization, activated AMPK, suppressed HIF-1α and AKT/mTOR signaling pathways, and promoted antitumor properties in NBR2-overexpressed TAMs, which were all reversed by the introduction of the miR-19a mimic. LncRNA NBR2 was verified to target miR-19a in macrophages according to the results of the luciferase assay. Collectively, lncRNA NBR2 may suppress the progression of CRC by downregulating miR-19a to regulate M2 macrophage polarization.

ZNF500 abolishes breast cancer proliferation and sensitizes chemotherapy by stabilizing P53 via competing with MDM2

Zinc finger protein 500 (ZNF500) has an unknown expression pattern and biological function in human tissues. Our study revealed that the ZNF500 mRNA and protein levels were higher in breast cancer tissues than those in their normal counterparts. However, ZNF500 expression was negatively correlated with advanced TNM stage (p = 0.018), positive lymph node metastasis (p = 0.014), and a poor prognosis (p < 0.001). ZNF500 overexpression abolished in vivo and in vitro breast cancer cell proliferation by activating the p53-p21-E2F4 signaling axis and directly interacting with p53 via its C2H2 domain. This may prevent ubiquitination of p53 in a manner that is competitive to MDM2, thus stabilizing p53. When ZNF500-∆C2H2 was overexpressed, the suppressed proliferation of breast cancer cells was neutralized in vitro and in vivo. In human breast cancer tissues, ZNF500 expression was positively correlated with p53 (p = 0.022) and E2F4 (p = 0.004) expression. ZNF500 expression was significantly lower in patients with Miller/Payne Grade 1-2 than in those with Miller/Payne Grade 3-5 (p = 0.012). ZNF500 suppresses breast cancer cell proliferation and sensitizes cells to chemotherapy.

Inhibition of SIRT6 aggravates p53-mediated ferroptosis in acute lung injury in mice

Although studies have shown that protein 53 (p53)-mediated ferroptosis is involved in acute lung injury (ALI), the mechanism of its regulation remains unclear. The protective effects of Sirtuin 6 (SIRT6), a histone deacetylase, have been demonstrated in multiple diseases; however, further studies are needed to elucidate the role of SIRT6 in ALI. In the present study, we hypothesize that SIRT6 protects against lipopolysaccharide (LPS)-induced ALI by regulating p53-mediated ferroptosis. We observed that the inhibition of ferroptosis prevented LPS-induced ALI. The knockout of p53 blocked LPS-induced ferroptosis and ALI, suggesting that p53 facilitated ALI by promoting ferroptosis. In addition, the inhibition of SIRT6 aggravated LPS-induced ferroptosis and ALI, while the depression of ferroptosis blocked the exacerbation of lung injury induced by SIRT6 inhibition. The results suggest that SIRT6 protects against ALI by regulating ferroptosis. Furthermore, the inhibition of SIRT6 reinforced the p53 acetylation and the deletion of p53 rescued the exacerbation of ferroptosis induced by SIRT6 inhibition. The findings indicate that SIRT6 regulates the acetylation of p53 and prevents p53-mediated ferroptosis. In conclusion, our results indicate that SIRT6 protects against LPS-induced ALI by regulating p53-mediated ferroptosis, thereby demonstrating that SIRT6 holds great promise as a therapeutic target for ALI.

Unleashing ferroptosis for cancer therapy with warfarin

Ferroptosis holds promise for cancer therapy. A recent study by Yang et al. in Cell Metabolism reveals that VKORC1L1-mediated reduction of vitamin K inhibits ferroptosis and establishes a direct p53-VKORC1L1 link in its regulation. As warfarin can inhibit VKORC1L1, the study further underscores this drug's potential as a cancer therapy.

The transportosome system as a model for the retrotransport of soluble proteins

The classic model of action of the glucocorticoid receptor (GR) sustains that its associated heat-shock protein of 90-kDa (HSP90) favours the cytoplasmic retention of the unliganded GR, whereas the binding of steroid triggers the dissociation of HSP90 allowing the passive nuclear accumulation of GR. In recent years, it was described a molecular machinery called transportosome that is responsible for the active retrograde transport of GR. The transportosome heterocomplex includes a dimer of HSP90, the stabilizer co-chaperone p23, and FKBP52 (FK506-binding protein of 52-kDa), an immunophilin that binds dynein/dynactin motor proteins. The model shows that upon steroid binding, FKBP52 is recruited to the GR allowing its active retrograde transport on cytoskeletal tracks. Then, the entire GR heterocomplex translocates through the nuclear pore complex. The HSP90-based heterocomplex is released in the nucleoplasm followed by receptor dimerization. Subsequent findings demonstrated that the transportosome is also responsible for the retrotransport of other soluble proteins. Importantly, the disruption of this molecular oligomer leads to several diseases. In this article, we discuss the relevance of this transport machinery in health and disease.

Lysine succinylation, the metabolic bridge between cancer and immunity

Lysine succinylation is a naturally occurring post-translational modification (PTM) that regulates the stability and function of proteins. It can be regulated by enzymes such as SIRT5 and SIRT7. Recently, the effect and significance of lysine succinylation in cancer and its implication in immunity have been extensively explored. Lysine succinylation is involved in the malignant phenotype of cancer cells. Abnormal regulation of lysine succinylation occurs in different cancers, and inhibitors targeting lysine succinylation regulatory enzymes can be used as potential anti-cancer strategies. Therefore, this review focused on the target protein lysine succinylation and its functions in cancer and immunity, in order to provide a reference for finding more potential clinical cancer targets in the future.

MicroRNAs and colorectal cancer: clinical potential and regulatory networks

Colorectal cancer (CRC) is a serious global health concern, with a high incidence and mortality rate. Although there have been advancements in the early detection and treatment of CRC, therapy resistance is common. MicroRNAs (miRNAs), a type of small non-coding RNA that regulates gene expression, are key players in the initiation and progression of CRC. Recently, there has been growing attention to the complex interplay of miRNAs in cancer development. miRNAs are powerful RNA molecules that regulate gene expression and have been implicated in various physiological and pathological processes, including carcinogenesis. By identifying current challenges and limitations of treatment strategies and suggesting future research directions, this review aims to contribute to ongoing efforts to enhance CRC diagnosis and treatment. It also provides a comprehensive overview of the role miRNAs play in CRC carcinogenesis and explores the potential of miRNA-based therapies as a treatment option. Importantly, this review highlights the exciting potential of targeted modulation of miRNA function as a therapeutic approach for CRC.

Targeting mPGES-2 to protect against acute kidney injury via inhibition of ferroptosis dependent on p53

Acute kidney injury (AKI) is a clinical syndrome with high morbidity and mortality but no specific therapy. Microsomal prostaglandin E synthase-2 (mPGES-2) is a PGE2 synthase but can metabolize PGH2 to malondialdehyde by forming a complex with heme. However, the role and mechanism of action of mPGES-2 in AKI remain unclear. To examine the role of mPGES-2, both global and tubule-specific mPGES-2-deficient mice were treated with cisplatin to induce AKI. mPGES-2 knockdown or overexpressing HK-2 cells were exposed to cisplatin to cause acute renal tubular cell injury. The mPGES-2 inhibitor SZ0232 was used to test the translational potential of targeting mPGES-2 in treating AKI. Additionally, mice were subjected to unilateral renal ischemia/reperfusion to further validate the effect of mPGES-2 on AKI. Interestingly, both genetic and pharmacological blockage of mPGES-2 led to decreased renal dysfunction and morphological damage induced by cisplatin and unilateral renal ischemia/reperfusion. Mechanistic exploration indicated that mPGES-2 deficiency inhibited ferroptosis via the heme-dependent regulation of the p53/SLC7A11/GPX4 axis. The present study indicates that mPGES-2 blockage may be a promising therapeutic strategy for AKI.

MicroRNA-96-5p is negatively regulating GPC3 in the metastasis of papillary thyroid cancer

BACKGROUNDS

Papillary thyroid cancer is the most common pathological type of thyroid cancer. miR-96-5p, a member of the miR-183 family, constitute a polycistronic miRNA cluster. In breast cancer, miR-96-5p promotes cell invasion, migration, and proliferation in vitro by inhibiting PTPN9. Moreover, miR-96-5p was reported to function as an oncogene in many cancers. However, whether miR-96-5p is involved in the development of papillary thyroid cancers and its potential mechanism is still unknown. The present study aims to explore the relationship between miR-96-5p and GPC3 expression in the development of papillary thyroid cancers.

METHODS

Transcriptomic sequencing was carried out using six pairs of papillary thyroid cancer and adjacent normal tissues. Quantitative real-time polymerase chain reaction (PCR) experiments were performed to examine the expression of genes.

RESULTS

In total, there were 1588 up-regulated and 1803 down-regulated differentially expressed genes between papillary thyroid cancer and normal tissues. Gene ontology and Kyoto encyclopedia of genes and genomes analysis revealed that extracellular matrix structure and proteoglycans were mainly involved in papillary thyroid cancer. Among the cluster of proteoglycans, GPC3 was significantly down-regulated in papillary thyroid cancer and is a target of miR-96.

CONCLUSION

miR-96-5p participates in the development of papillary thyroid cancer by regulating the expression of GPC3. Thus, targeting miR-96-5p may be a potential therapeutic approach for preventing and treating papillary thyroid cancer.

NAD+: An Old but Promising Therapeutic Agent for Skeletal Muscle Ageing

More than a century after the discovery of nicotinamide adenine dinucleotide (NAD+), our understanding of the molecule's role in the biology of ageing continues to evolve. As a coenzyme or substrate for many enzymes, NAD+ governs a wide range of biological processes, including energy metabolism, genomic stability, signal transduction, and cell fate. NAD+ deficiency has been recognised as a bona fide hallmark of tissue degeneration, and restoring NAD+ homeostasis helps to rejuvenate multiple mechanisms associated with tissue ageing. The progressive loss of skeletal muscle homeostasis with age is directly associated with high morbidity, disability and mortality. The aetiology of skeletal muscle ageing is complex, involving mitochondrial dysfunction, senescence and stem cell depletion, autophagy defects, chronic cellular stress, intracellular ion overload, immune cell dysfunction, circadian clock disruption, microcirculation disorders, persistent denervation, and gut microbiota dysbiosis. This review focuses on the therapeutic potential of NAD+ restoration to alleviate the above pathological factors and discusses the effects of in vivo administration of different NAD+ boosting strategies on skeletal muscle homeostasis, aiming to provide a reference for combating skeletal muscle ageing.

Biological Effects of HDAC Inhibitors Vary with Zinc Binding Group: Differential Effects on Zinc Bioavailability, ROS Production, and R175H p53 Mutant Protein Reactivation

The coordination of zinc by histone deacetylase inhibitors (HDACi), altering the bioavailability of zinc to histone deacetylases (HDACs), is key to HDAC enzyme inhibition. However, the ability of zinc binding groups (ZBGs) to alter intracellular free Zn+2 levels, which may have far-reaching effects, has not been explored. Using two HDACis with different ZBGs, we documented shifts in intracellular free Zn+2 concentrations that correlate with subsequent ROS production. Next, we assayed refolding and reactivation of the R175H mutant p53 protein in vitro to provide greater biological context as the activity of this mutant depends on cellular zinc concentration. The data presented demonstrates the differential activity of HDACi in promoting R175H response element (RE) binding. After cells are treated with HDACi, there are differences in R175H mutant p53 refolding and reactivation, which may be related to treatments. Collectively, we show that HDACis with distinct ZBGs differentially impact the intracellular free Zn+2 concentration, ROS levels, and activity of R175H; therefore, HDACis may have significant activity independent of their ability to alter acetylation levels. Our results suggest a framework for reevaluating the role of zinc in the variable or off-target effects of HDACi, suggesting that the ZBGs of HDAC inhibitors may provide bioavailable zinc without the toxicity associated with zinc metallochaperones such as ZMC1.

Lipocalin-2: A Nurturer of Tumor Progression and a Novel Candidate for Targeted Cancer Therapy

Within the tumor microenvironment (TME) exists a complex signaling network between cancer cells and stromal cells, which determines the fate of tumor progression. Hence, interfering with this signaling network forms the basis for cancer therapy. Yet, many types of cancer, in particular, solid tumors, are refractory to the currently used treatments, so there is an urgent need for novel molecular targets that could improve current anti-cancer therapeutic strategies. Lipocalin-2 (Lcn-2), a secreted siderophore-binding glycoprotein that regulates iron homeostasis, is highly upregulated in various cancer types. Due to its pleiotropic role in the crosstalk between cancer cells and stromal cells, favoring tumor progression, it could be considered as a novel biomarker for prognostic and therapeutic purposes. However, the exact signaling route by which Lcn-2 promotes tumorigenesis remains unknown, and Lcn-2-targeting moieties are largely uninvestigated. This review will (i) provide an overview on the role of Lcn-2 in orchestrating the TME at the level of iron homeostasis, macrophage polarization, extracellular matrix remodeling, and cell migration and survival, and (ii) discuss the potential of Lcn-2 as a promising novel drug target that should be pursued in future translational research.

PTPN1 is a prognostic biomarker related to cancer immunity and drug sensitivity: from pan-cancer analysis to validation in breast cancer

Background

Protein tyrosine phosphatase non-receptor type 1 (PTPN1), a member of the protein tyrosine phosphatase superfamily, has been identified as an oncogene and therapeutic target in various cancers. However, its precise role in determining the prognosis of human cancer and immunological responses remains elusive. This study investigated the relationship between PTPN1 expression and clinical outcomes, immune infiltration, and drug sensitivity in human cancers, which will improve understanding regarding its prognostic value and immunological role in pan-cancer.

Methods

The PTPN1 expression profile was obtained from The Cancer Genome Atlas and Cancer Cell Line Encyclopedia databases. Kaplan-Meier, univariate Cox regression, and time-dependent receiver operating characteristic curve analyses were utilized to clarify the relationship between PTPN1 expression and the prognosis of pan-cancer patients. The relationships between PTPN1 expression and the presence of tumor-infiltrated immune cells were analyzed using Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data and Tumor Immune Estimation Resource. The cell counting kit-8 (CCK-8) assay was performed to examine the effects of PTPN1 level on the sensitivity of breast cancer cells to paclitaxel. Immunohistochemistry and immunoblotting were used to investigate the relationship between PTPN1 expression, immune cell infiltration, and immune checkpoint gene expression in human breast cancer tissues and a mouse xenograft model.

Results

The pan-cancer analysis revealed that PTPN1 was frequently up-regulated in various cancers. High PTPN1 expression was associated with poor prognosis in most cancers. Furthermore, PTPN1 expression correlated highly with the presence of tumor-infiltrating immune cells and the expression of immune checkpoint pathway marker genes in different cancers. Furthermore, PTPN1 significantly predicted the prognosis for patients undergoing immunotherapy. The results of the CCK-8 viability assay revealed that PTPN1 knockdown increased the sensitivity of MDA-MB-231 and MCF-7 cells to paclitaxel. Finally, our results demonstrated that PTPN1 was associated with immune infiltration and immune checkpoint gene expression in breast cancer.

Conclusion

PTPN1 was overexpressed in multiple cancer types and correlated with the clinical outcome and tumor immunity, suggesting it could be a valuable potential prognostic and immunological biomarker for pan-cancer.

Permission to pass: on the role of p53 as a gatekeeper for aneuploidy

Aneuploidy-the karyotype state in which the number of chromosomes deviates from a multiple of the haploid chromosome set-is common in cancer, where it is thought to facilitate tumor initiation and progression. However, it is poorly tolerated in healthy cells: during development and tissue homeostasis, aneuploid cells are efficiently cleared from the population. It is still largely unknown how cancer cells become, and adapt to being, aneuploid. P53, the gatekeeper of the genome, has been proposed to guard against aneuploidy. Aneuploidy in cancer genomes strongly correlates with mutations in TP53, and p53 is thought to prevent the propagation of aneuploid cells. Whether p53 also participates in preventing the mistakes in cell division that lead to aneuploidy is still under debate. In this review, we summarize the current understanding of the role of p53 in protecting cells from aneuploidy, and we explore the consequences of functional p53 loss for the propagation of aneuploidy in cancer.

Recent advances in natural compounds inducing non-apoptotic cell death for anticancer drug resistance

The induction of cell death is recognized as a potent strategy for cancer treatment. Apoptosis is an extensively studied form of cell death, and multiple anticancer drugs exert their therapeutic effects by inducing it. Nonetheless, apoptosis evasion is a hallmark of cancer, rendering cancer cells resistant to chemotherapy drugs. Consequently, there is a growing interest in exploring novel non-apoptotic forms of cell death, such as ferroptosis, necroptosis, pyroptosis, and paraptosis. Natural compounds with anticancer properties have garnered significant attention due to their advantages, including a reduced risk of drug resistance. Over the past two decades, numerous natural compounds have been discovered to exert anticancer and anti-resistance effects by triggering these four non-apoptotic cell death mechanisms. This review primarily focuses on these four non-apoptotic cell death mechanisms and their recent advancements in overcoming drug resistance in cancer treatment. Meanwhile, it highlights the role of natural compounds in effectively addressing cancer drug resistance through the induction of these forms of non-apoptotic cell death.

Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Prognostic risk of immune-associated signature in the microenvironment of brain gliomas

Understanding the key factors in the tumor microenvironment (TME) that affect the prognosis of gliomas is crucial. In this study, we sought to uncover the prognostic significance of immune cells and immune-related genes in the TME of gliomas. We incorporated data of 970 glioma patient samples from the Chinese Glioma Genome Atlas (CGGA) database as the training set, and an additional set of 666 samples from The Cancer Genome Atlas (TCGA) database served as the validation set. From our analysis, we identified 21 immune-related differentially expressed genes (DEGs) in the TME, which holds implications for glioma prognosis. Based on these genes, we constructed a prognostic risk model on the 21 genes. The prognostic risk model demonstrated robust performance with an area under the curve (AUC) value of 0.848. Notably, the risk score derived from the model emerged as an independent prognostic factor of gliomas, with high risk scores indicative of an unfavorable prognosis. Furthermore, we observed that high infiltration levels of certain immune cells, namely, activated dendritic cells, M0 macrophages, M2 macrophages, and regulatory T cells (Tregs), correlated with an unfavorable glioma prognosis. In conclusion, our findings suggested that the TME of gliomas harbored a distinct immune-associated signature, comprising 21 immune-related genes and specific immune cells. These elements significantly influence the prognosis and present potential as novel indicators in the clinical assessment of glioma patient outcomes.

Mechanisms and regulations of ferroptosis

Regulation of cell mortality for disease treatment has been the focus of research. Ferroptosis is an iron-dependent regulated cell death whose mechanism has been extensively studied since its discovery. A large number of studies have shown that regulation of ferroptosis brings new strategies for the treatment of various benign and malignant diseases. Iron excess and lipid peroxidation are its primary metabolic features. Therefore, genes involved in iron metabolism and lipid metabolism can regulate iron overload and lipid peroxidation through direct or indirect pathways, thereby regulating ferroptosis. In addition, glutathione (GSH) is the body's primary non-enzymatic antioxidants and plays a pivotal role in the struggle against lipid peroxidation. GSH functions as an auxiliary substance for glutathione peroxidase 4 (GPX4) to convert toxic lipid peroxides to their corresponding alcohols. Here, we reviewed the researches on the mechanism of ferroptosis in recent years, and comprehensively analyzed the mechanism and regulatory process of ferroptosis from iron metabolism and lipid metabolism, and then described in detail the metabolism of GPX4 and the main non-enzymatic antioxidant GSH in vivo.

SLC35F2-SYVN1-TRIM59 axis critically regulates ferroptosis of pancreatic cancer cells by inhibiting endogenous p53

Pancreatic cancer cells undergo intricate metabolic reprogramming to sustain their survival and proliferation. p53 exhibits a dual role in tumor cell ferroptosis. However, the precise role and mechanisms underlying wild-type p53 activation in promoting ferroptosis in pancreatic cancer cells remain obscure. In this study, we applied bioinformatics tools and performed an analysis of clinical tissue sample databases and observed a significantly upregulated expression of solute carrier family 35 member F2 (SLC35F2) in pancreatic cancer tissues. Our clinical investigations indicated that elevated SLC35F expression was related to adverse survival outcomes. Through multi-omics analyses, we discerned that SLC35F2 influences the transcriptome and inhibits ferroptosis in pancreatic cancer cells. Moreover, our findings reveal the pivotal involvement of p53 in mediating SLC35F2-mediated ferroptosis, both in vitro and in vivo. SLC35F2 inhibits ferroptosis by facilitating TRIM59-mediated p53 degradation. Further mechanistic investigations demonstrated that SLC35F2 competitively interacts with the E3 ubiquitin ligase SYVN1 of TRIM59, thereby stabilizing TRIM59 expression and consequentially promoting p53 degradation. Utilizing protein 3D structure analysis and drug screening, we identified irinotecan hydrochloride and lapatinib ditosylate as compounds targeting SLC35F2, augmenting the antitumor effect of imidazole ketone erastin (IKE) in a wild-type p53 patient-derived xenograft (PDX) model. However, in the p53 mutant PDX model, irinotecan hydrochloride and lapatinib ditosylate did not alter the sensitivity of the tumor xenograft model to IKE-triggered ferroptosis. In summary, our work establishes a novel mechanism wherein the SLC35F2-SYVN1-TRIM59 axis critically regulates ferroptosis of pancreatic cancer cells by inhibiting endogenous p53. Thus, SLC35F2 emerges as a promising therapeutic target for treating pancreatic cancer.

p53 at the crossroad between mitochondrial reactive oxygen species and necroptosis

p53 is a redox-sensitive transcription factor that can regulate multiple cell death programs through different signaling pathways. In this review, we assess the role of p53 in the regulation of necroptosis, a programmed form of lytic cell death highly involved in the pathophysiology of multiple diseases. In particular, we focus on the role of mitochondrial reactive oxygen species (mtROS) as essential contributors to modulate necroptosis execution through p53. The enhanced generation of mtROS during necroptosis is critical for the correct interaction between receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and 3 (RIPK3), two key components of the functional necrosome. p53 controls the occurrence of necroptosis by modulating the levels of mitochondrial H2O2 via peroxiredoxin 3 and sulfiredoxin. Furthermore, in response to increased levels of H2O2, p53 upregulates the long non-coding RNA necrosis-related factor, favoring the translation of RIPK1 and RIPK3. In parallel, a fraction of cytosolic p53 migrates into mitochondria, a process notably involved in necroptosis execution via its interaction with the mitochondrial permeability transition pore. In conclusion, p53 is located at the intersection between mtROS and the necroptosis machinery, making it a key protein to orchestrate redox signaling during necroptosis.