Unravelling mechanisms of p53-mediated tumour suppression

A naturally derived small molecule compound suppresses tumor growth and metastasis in mice by relieving p53-dependent repression of CDK2/Rb signaling and the Snail-driven EMT

The tumor suppressor protein p53 is central to cancer biology, with its pathway reactivation emerging as a promising therapeutic strategy in oncology. This study introduced LZ22, a novel compound that selectively inhibits the growth, migration, and metastasis of tumor cells expressing wild-type p53, demonstrating ineffectiveness in cells devoid of p53 or those expressing mutant p53. LZ22's mechanism of action involves a high-affinity interaction with the histidine-96 pocket of the MDM2 protein. This interaction disrupted the MDM2-p53 binding, consequently stabilizing p53 by shielding it from proteasomal degradation. LZ22 impeded cell cycle progression and diminished cell proliferation by reinstating the p53-dependent suppression of the CDK2/Rb signaling pathway. Moreover, LZ22 alleviated the p53-dependent repression of Snail transcription factor expression and its consequent EMT, effectively reducing tumor cell migration and distal metastasis. Importantly, LZ22 administration in tumor-bearing mice did not manifest notable side effects. The findings position LZ22 as a structurally unique reactivator of p53, offering therapeutic promise for the management of human cancers with wild-type TP53.

MYH9: A key protein involved in tumor progression and virus-related diseases

The myosin heavy chain 9 (MYH9) gene encodes the heavy chain of non-muscle myosin IIA (NMIIA), which belongs to the myosin II subfamily of actin-based molecular motors. Previous studies have demonstrated that abnormal expression and mutations of MYH9 were correlated with MYH9-related diseases and tumors. Furthermore, earlier investigations identified MYH9 as a tumor suppressor. However, subsequent research revealed that MYH9 promoted tumorigenesis, progression and chemoradiotherapy resistance. Note-worthily, MYH9 has also been linked to viral infections, like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Epstein-Barr virus, and hepatitis B virus, as a receptor or co-receptor. In addition, MYH9 promotes the development of hepatocellular carcinoma by interacting with the hepatitis B virus-encoding X protein. Finally, various findings highlighted the role of MYH9 in the development of these illnesses, especially in tumors. This review summarizes the involvement of the MYH9-regulated signaling network in tumors and virus-related diseases and presents possible drug interventions on MYH9, providing insights for the use of MYH9 as a therapeutic target for tumors and virus-mediated diseases.

P53 together with ferroptosis: a promising strategy leaving cancer cells without escape

TP53, functioning as the keeper of the genome, assumes a pivotal function in the inhibition of tumorigenesis. Recent studies have revealed that p53 regulates ferroptosis pathways within tumor cells and is closely related to tumorigenesis. Therefore, we summarize the pathways and mechanisms by which p53 regulates ferroptosis and identify a series of upstream and downstream molecules involved in this process. Furthermore, we construct a p53-ferroptosis network centered on p53. Finally, we present the progress of drugs to prevent wild-type p53 (wtp53) degeneration and restore wtp53, highlighting the deficiencies of drug development and the prospects for p53 in cancer treatment. These findings provide novel strategies and directions for future cancer therapy.

Ferroptosis: Emerging mechanisms, biological function, and therapeutic potential in cancer and inflammation

Ferroptosis represents a distinct form of programmed cell death triggered by excessive iron accumulation and lipid peroxidation-induced damage. This mode of cell death differentiates from classical programmed cell death in terms of morphology and biochemistry. Ferroptosis stands out for its exceptional biological characteristics and has garnered extensive research and conversations as a form of programmed cell death. Its dysfunctional activation is closely linked to the onset of diseases, particularly inflammation and cancer, making ferroptosis a promising avenue for combating these conditions. As such, exploring ferroptosis may offer innovative approaches to treating cancer and inflammatory diseases. Our review provides insights into the relevant regulatory mechanisms of ferroptosis, examining the impact of ferroptosis-related factors from both physiological and pathological perspectives. Describing the crosstalk between ferroptosis and tumor- and inflammation-associated signaling pathways and the potential of ferroptosis inducers in overcoming drug-resistant cancers are discussed, aiming to inform further novel therapeutic directions for ferroptosis in relation to inflammatory and cancer diseases.

Deciphering the role of neddylation in tumor microenvironment modulation: common outcome of multiple signaling pathways

Neddylation is a post-translational modification process, similar to ubiquitination, that controls several biological processes. Notably, it is often aberrantly activated in neoplasms and plays a critical role in the intricate dynamics of the tumor microenvironment (TME). This regulatory influence of neddylation permeates extensively and profoundly within the TME, affecting the behavior of tumor cells, immune cells, angiogenesis, and the extracellular matrix. Usually, neddylation promotes tumor progression towards increased malignancy. In this review, we highlight the latest understanding of the intricate molecular mechanisms that target neddylation to modulate the TME by affecting various signaling pathways. There is emerging evidence that the targeted disruption of the neddylation modification process, specifically the inhibition of cullin-RING ligases (CRLs) functionality, presents a promising avenue for targeted therapy. MLN4924, a small-molecule inhibitor of the neddylation pathway, precisely targets the neural precursor cell-expressed developmentally downregulated protein 8 activating enzyme (NAE). In recent years, significant advancements have been made in the field of neddylation modification therapy, particularly the integration of MLN4924 with chemotherapy or targeted therapy. This combined approach has demonstrated notable success in the treatment of a variety of hematological and solid tumors. Here, we investigated the inhibitory effects of MLN4924 on neddylation and summarized the current therapeutic outcomes of MLN4924 against various tumors. In conclusion, this review provides a comprehensive, up-to-date, and thorough overview of neddylation modifications, and offers insight into the critical importance of this cellular process in tumorigenesis.

S1PR2 inhibition mitigates cognitive deficit in diabetic mice by modulating microglial activation via Akt-p53-TIGAR pathway

Cognitive deficit is one of the challenging complications of type 2 diabetes. Sphingosine 1- phosphate receptors (S1PRs) have been implicated in various neurodegenerative and metabolic disorders. The association of S1PRs and cognition in type 2 diabetes remains elusive. Microglia-mediated neuronal damage could be the thread propagating cognitive deficit. The effects of S1PR2 inhibition on cognition in high-fat diet and streptozotocin-induced diabetic mice were examined in this work. We further assessed microglial activation and putative microglial polarisation routes. Cognitive function loss was observed after four months of diabetes induction in Type 2 diabetes animal model. JTE013, an S1PR2 inhibitor, was used to assess neuroprotection against cognitive decline and neuroinflammation in vitro and in vivo diabetes model. JTE013 (10 mg/kg) improved synaptic plasticity by upregulating psd95 and synaptophysin while reducing cognitive decline and neuroinflammation. It further enhanced anti-inflammatory microglia in the hippocampus and prefrontal cortex (PFC), as evidenced by increased Arg-1, CD206, and YM-1 levels and decreased iNOS, CD16, and MHCII levels. TIGAR, TP53-induced glycolysis and apoptosis regulator, might facilitate the anti-inflammatory microglial phenotype by promoting oxidative phosphorylation and decreasing apoptosis. However, since p53 is a TIGAR suppressor, inhibiting p53 could be beneficial. S1PR2 inhibition increased p-Akt and TIGAR levels and reduced the levels of p53 in the PFC and hippocampus of type 2 diabetic mice, thereby decreasing apoptosis. In vitro, palmitate was used to imitate sphingolipid dysregulation in BV2 cells, followed by conditioned media exposure to Neuro2A cells. JTE013 rescued the palmitate-induced neuronal apoptosis by promoting the anti-inflammatory microglia. In the present study, we demonstrate that the inhibition of S1PR2 improves cognitive function and skews microglia toward anti-inflammatory phenotype in type 2 diabetic mice, thereby promising to be a potential therapy for neuroinflammation.

SIRT7 and p53 interaction in embryonic development and tumorigenesis

p53 is a hallmark tumor suppressor due in part to its role in cell cycle progression, DNA damage repair, and cellular apoptosis; its protein activity interrelates with the Sirtuin family of proteins, major regulators of the cellular response to metabolic, oxidative, and genotoxic stress. In the recent years, mammalian Sirtuin 7 (SIRT7) has emerged as a pivotal regulator of p53, fine-tuning its activity in a context dependent manner. SIRT7 is frequently overexpressed in human cancer, yet its precise role in tumorigenesis and whether it involves p53 regulation is insufficiently understood. Depletion of SIRT7 in mice results in impaired embryo development and premature aging. While p53 activity has been suggested to contribute to tissue specific dysfunction in adult Sirt7 -/- mice, whether this also applies during development is currently unknown. By generating SIRT7 and p53 double-knockout mice, here we show that the demise of SIRT7-deficient embryos is not the result of p53 activity. Notably, although SIRT7 is commonly considered an oncogene, SIRT7 haploinsufficiency increases tumorigenesis in p53 knockout mice. Remarkably, in specific human tumors harboring p53 mutation, we identified that SIRT7 low expression correlates with poor patient prognosis. Transcriptomic analysis unveils a previously unrecognized interplay between SIRT7 and p53 in epithelial-to-mesenchymal transition (EMT) and extracellular matrix regulation with major implications for our understanding of embryonic development and tumor progression.

Interplay of oxidative stress, cellular communication and signaling pathways in cancer

Cancer remains a significant global public health concern, with increasing incidence and mortality rates worldwide. Oxidative stress, characterized by the production of reactive oxygen species (ROS) within cells, plays a critical role in the development of cancer by affecting genomic stability and signaling pathways within the cellular microenvironment. Elevated levels of ROS disrupt cellular homeostasis and contribute to the loss of normal cellular functions, which are associated with the initiation and progression of various types of cancer. In this review, we have focused on elucidating the downstream signaling pathways that are influenced by oxidative stress and contribute to carcinogenesis. These pathways include p53, Keap1-NRF2, RB1, p21, APC, tumor suppressor genes, and cell type transitions. Dysregulation of these pathways can lead to uncontrolled cell growth, impaired DNA repair mechanisms, and evasion of cell death, all of which are hallmark features of cancer development. Therapeutic strategies aimed at targeting oxidative stress have emerged as a critical area of investigation for molecular biologists. The objective is to limit the response time of various types of cancer, including liver, breast, prostate, ovarian, and lung cancers. By modulating the redox balance and restoring cellular homeostasis, it may be possible to mitigate the damaging effects of oxidative stress and enhance the efficacy of cancer treatments. The development of targeted therapies and interventions that specifically address the impact of oxidative stress on cancer initiation and progression holds great promise in improving patient outcomes. These approaches may include antioxidant-based treatments, redox-modulating agents, and interventions that restore normal cellular function and signaling pathways affected by oxidative stress. In summary, understanding the role of oxidative stress in carcinogenesis and targeting this process through therapeutic interventions are of utmost importance in combating various types of cancer. Further research is needed to unravel the complex mechanisms underlying oxidative stress-related pathways and to develop effective strategies that can be translated into clinical applications for the management and treatment of cancer. Video Abstract.

Designed novel nuclear localizing anticancer peptide targets p53 negative regulator MDM2 protein

Intracellular protein-protein interactions provide a major therapeutic target for the development of peptide-based anticancer therapeutic agents. MDM2 is the 491-residue protein encoded by the MDM2 oncogene. Being a ubiquitin-protein ligase, MDM2 represses the transcription ability of the tumor suppressor p53 by proteasome-mediated degradation. Under typical cellular circumstances, a sustained p53 expression level is maintained by negative regulation of MDM2, whereas under stress conditions, this is alleviated to increase the p53 level. Modulation of MDM2-p53 interaction via fabrication of an MDM2-interacting peptide could be a useful strategy to inhibit subsequent proteasomal degradation of p53 and initiation of p53 signaling leading to the initiation of p53-mediated apoptosis of tumor cells. Here, in this research work, a novel anticancer peptide mPNC-NLS targeting the nucleus and the MDM2 protein (p53 negative regulator) was designed to promote the p53 protein activity for the prevention of cancer. It induces effective apoptosis in both A549 and U87 cells and remains non-cytotoxic to normal lung fibroblast cells (WI38). Further, immunocytochemistry and Western blot results confirm that the designed mPNC-NLS peptide induces the apoptotic death of lung cancer cells via activation of p53 and p21 proteins and remarkably stifled the in vitro growth of 3D multicellular spheroids composed of A549 cells.

Rescue of p53 functions by in vitro-transcribed mRNA impedes the growth of high-grade serous ovarian cancer

BACKGROUND

The cellular tumor protein p53 (TP53) is a tumor suppressor gene that is frequently mutated in human cancers. Among various cancer types, the very aggressive high-grade serous ovarian carcinoma (HGSOC) exhibits the highest prevalence of TP53 mutations, present in >96% of cases. Despite intensive efforts to reactivate p53, no clinical drug has been approved to rescue p53 function. In this study, our primary objective was to administer in vitro-transcribed (IVT) wild-type (WT) p53-mRNA to HGSOC cell lines, primary cells, and orthotopic mouse models, with the aim of exploring its impact on inhibiting tumor growth and dissemination, both in vitro and in vivo.

METHODS

To restore the activity of p53, WT p53 was exogenously expressed in HGSOC cell lines using a mammalian vector system. Moreover, IVT WT p53 mRNA was delivered into different HGSOC model systems (primary cells and patient-derived organoids) using liposomes and studied for proliferation, cell cycle progression, apoptosis, colony formation, and chromosomal instability. Transcriptomic alterations induced by p53 mRNA were analyzed using RNA sequencing in OVCAR-8 and primary HGSOC cells, followed by ingenuity pathway analysis. In vivo effects on tumor growth and metastasis were studied using orthotopic xenografts and metastatic intraperitoneal mouse models.

RESULTS

Reactivation of the TP53 tumor suppressor gene was explored in different HGSOC model systems using newly designed IVT mRNA-based methods. The introduction of WT p53 mRNA triggered dose-dependent apoptosis, cell cycle arrest, and potent long-lasting inhibition of HGSOC cell proliferation. Transcriptome analysis of OVCAR-8 cells upon mRNA-based p53 reactivation revealed significant alterations in gene expression related to p53 signaling, such as apoptosis, cell cycle regulation, and DNA damage. Restoring p53 function concurrently reduces chromosomal instability within the HGSOC cells, underscoring its crucial contribution in safeguarding genomic integrity by moderating the baseline occurrence of double-strand breaks arising from replication stress. Furthermore, in various mouse models, treatment with p53 mRNA reduced tumor growth and inhibited tumor cell dissemination in the peritoneal cavity in a dose-dependent manner.

CONCLUSIONS

The IVT mRNA-based reactivation of p53 holds promise as a potential therapeutic strategy for HGSOC, providing valuable insights into the molecular mechanisms underlying p53 function and its relevance in ovarian cancer treatment.

Emerging Role of Ferroptosis in Breast Cancer: Characteristics, Therapy, and Translational Implications for the Present and Future

Ferroptosis is a nonapoptotic, iron-dependent form of cell death that can be actuated in disease cells by expected improvements and manufactured specialists. Different studies have recently resurrected the role of this newly discovered cell death pathway and demonstrated its efficacy in treating breast cancer. Breast cancer is the most well-known type of cancer among women worldwide. Despite many years of research focusing on cell death in breast cancer, counting apoptosis, clinical treatment leftovers are difficult due to the high likelihood of recurrence. Ferroptosis is defined by a lack of lipid peroxide repair capacity by phospholipid hydroperoxides GPX4, accessibility of redox-active iron, and followed oxidation of polyunsaturated fatty acids acid-containing phospholipids signalling, amino acid and iron metabolism, ferritinophagy, epithelial-tomesenchymal transition, cell adhesion, and mevalonate and phospholipid biosynthesis can all be factors that influence ferroptosis susceptibility. Ferroptosis, an iron-dependent controlled cell death caused by excessive lipid peroxidation, has been entwined in breast cancer development and therapeutic response for the past decade. Advances in enhancing clinical drugs targeting ferroptosis are developing silver linings to treat breast cancer. Ferroptosis is influenced by metabolism and the expression of certain genes, making it a prospective therapeutic target for monitoring malignant growth and an appealing target for precision cancer medication disclosure. In the coming years, research into biomarkers to follow ferroptosis in patients with breast cancer and the course of events and the subsequent use of novel ferroptosis-based treatments will be captious. We present a fundamental analysis of the actual understanding of molecular mechanisms along with regulatory networks associated with ferroptosis, expected physiological functions in growth concealment, ferroptosis-associated differentially expressed genes, treatment targeting potential, and recent advances in the development of therapeutic strategies in this review.

Role of intrinsic apoptosis in environmental exposure health outcomes

Environmental exposures are linked to diseases of high public health concern, including cancer, neurodegenerative disorders, and autoimmunity. These diseases are caused by excessive or insufficient cell death, prompting investigation of mechanistic links between environmental toxicants and dysregulation of cell death pathways, including apoptosis. This review describes how legacy and emerging environmental exposures target the intrinsic apoptosis pathway to potentially drive pathogenesis. Recent discoveries reveal that dynamic regulation of apoptosis may heighten the vulnerability of healthy tissues to exposures in children, and that apoptotic signaling can guide immune responses, tissue repair, and tumorigenesis. Understanding how environmental toxicants dysregulate apoptosis will uncover opportunities to deploy apoptosis-modulating agents for the treatment or prevention of exposure-linked diseases.

Exploring the Potential Role of Phytopharmaceuticals in Alleviating Toxicities of Chemotherapeutic Agents

BACKGROUND

Chemotherapy is the mainstay of cancer treatment, bringing patients optimism about recurrence and survival. However, the clinical effectiveness of chemotherapeutic drugs is frequently jeopardized by their intrinsic toxicity, resulting in side effects affecting the quality of life of cancer patients. This analysis explores the ethnopharmacological impact of phytopharmaceuticals, highlighting their traditional use in many cultures. The present study, which takes its cues from indigenous knowledge, aims to close the knowledge gap between traditional medicine and modern medicine in reducing the toxicities of chemotherapy treatments.

AIM

The present in-depth study aims to highlight the current research and upcoming developments in phytopharmaceuticals for reducing the toxicity of chemotherapeutic drugs. Further, we address the mechanisms through which phytopharmaceuticals may reduce chemotherapy-induced side effects that include nausea, vomiting, myelosuppression, nephropathy, neuropathy, and cardiotoxicity using data from a variety of preclinical and clinical investigations.

MATERIALS AND METHODS

The literature search was carried out by employing search engines such as PubMed and Google Scholar with keywords such as cancer, chemotherapy, CNS toxicity, hematopoietic toxicity, renal toxicity, GI toxicity, CNS toxicity, and phytopharmaceuticals.

RESULTS

Bioactive chemicals found in plants, such as fruits, vegetables, herbs, and spices, are being studied for their capacity to improve the safety and acceptability of chemotherapy regimens. The current review also dives into the investigation of phytopharmaceuticals as adjuvant medicines in cancer treatment, which is a viable path for addressing the pressing need to lessen chemotherapy-induced toxicities.

CONCLUSION

The present review revealed that the potential of phytopharmaceuticals in alleviating chemotherapeutic drug toxicities would pave the way for better cancer treatment and patient outcomes, harmonizing with the larger trend towards personalized and holistic approaches to chemotherapy.

Study of the curative effect of Zhang's Xibi formula and its underlying mechanism involving inhibition of inflammatory responses and delay of knee osteoarthritis

OBJECTIVE

To verify the clinical efficacy of Zhang's Xibi formula (ZSXBF) and explain the mechanism underlying its therapeutic effect.

METHODS

Preliminary elucidation of the clinical efficacy of ZSXBF in treating KOA in self-control studies, exploration of its mechanism of action with network pharmacology methods, and validation in animal experiments.

RESULTS

In clinical studies, ZSXBF administration effectively improved patient quality of life and reduce pain. Network pharmacology was used to explore the possible mechanisms underlying its treatment effect, and after verification in clinical experience and animal experiments, it was found that ZSXBF regulated the expression of immune-related proteins such as IL-17, ERK1, and TP53 in mouse knee joints.

CONCLUSION

ZSXBF, which is a traditional Chinese medicine compound that is used to clear heat and detoxify, can effectively improve the clinical symptoms of KOA patients, and its underlying mechanism includes the regulation of human immune-related proteins.

A CRISPR-Cas9 library screening identifies CARM1 as a critical inhibitor of ferroptosis in hepatocellular carcinoma cells

Ferroptosis is an iron-catalyzed form of regulated cell death that results from the accumulation of lipid peroxidation products and reactive oxygen species to a lethal content. However, the transcriptional regulation of ferroptosis is not well understood. Sorafenib, a standard drug for hepatocellular carcinoma (HCC), induces ferroptosis in HCC cells. In this study, we conducted a CRISPR-Cas9 library screening targeting epigenetic factors and identified coactivator-associated arginine methyltransferase 1 (CARM1) as a critical inhibitor of ferroptosis. CARM1 depletion intensified Sorafenib-induced ferroptosis, resulting in decreased cell viability, reduced cellular glutathione level, increased lipid peroxidation, and altered mitochondrial crista structure. Additionally, we investigated a CARM1 inhibitor (CARM1i) as a potential ferroptosis inducer. Combining the CARM1i with Sorafenib enhanced the induction of ferroptosis. Notably, both CARM1 knockdown and CARM1i showed cooperative effects with Sorafenib in inhibiting HCC growth in mice. The underlying mechanism involves CARM1-catalyzed H3R26me2a on the promoter of glutathione peroxidase 4, leading to its transcriptional activation and subsequent ferroptosis inhibition. Furthermore, Sorafenib treatment induced the transcription of CARM1 through the MDM2-p53 axis. In summary, our findings establish CARM1 as a critical ferroptosis inhibitor and highlight the potential of CARM1is as novel ferroptosis inducers, providing promising therapeutic strategies for HCC treatment.

The Evolving Landscape of Therapeutics for Epilepsy in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder characterized by benign tumor growth in multiple organs, including the brain, kidneys, heart, eyes, lungs, and skin. Pathogenesis stems from mutations in either the TSC1 or TSC2 gene, which encode the proteins hamartin and tuberin, respectively. These proteins form a complex that inhibits the mTOR pathway, a critical regulator of cell growth and proliferation. Disruption of the tuberin-hamartin complex leads to overactivation of mTOR signaling and uncontrolled cell growth, resulting in hamartoma formation. Neurological manifestations are common in TSC, with epilepsy developing in up to 90% of patients. Seizures tend to be refractory to medical treatment with anti-seizure medications. Infantile spasms and focal seizures are the predominant seizure types, often arising in early childhood. Drug-resistant epilepsy contributes significantly to morbidity and mortality. This review provides a comprehensive overview of the current state of knowledge regarding the pathogenesis, clinical manifestations, and treatment approaches for epilepsy and other neurological features of TSC. While narrative reviews on TSC exist, this review uniquely synthesizes key advancements across the areas of TSC neuropathology, conventional and emerging pharmacological therapies, and targeted treatments. The review is narrative in nature, without any date restrictions, and summarizes the most relevant literature on the neurological aspects and management of TSC. By consolidating the current understanding of TSC neurobiology and evidence-based treatment strategies, this review provides an invaluable reference that highlights progress made while also emphasizing areas requiring further research to optimize care and outcomes for TSC patients.

Bisabosqual A: A novel asparagine synthetase inhibitor suppressing the proliferation and migration of human non-small cell lung cancer A549 cells

Asparagine synthetase (ASNS) is a crucial enzyme for the de novo biosynthesis of endogenous asparagine (Asn), and ASNS shows the positive relationship with the growth of several solid tumors. Most of ASNS inhibitors are analogs of transition-state in ASNS reaction, but their low cell permeability hinders their anticancer activity. Therefore, novel ASNS inhibitors with a new pharmacophore urgently need to be developed. In this study, we established and applied a system for in vitro screening of ASNS inhibitors, and found a promising unique bisabolane-type meroterpenoid molecule, bisabosqual A (Bis A), able to covalently modify K556 site of ASNS protein. Bis A targeted ASNS to suppress cell proliferation of human non-small cell lung cancer A549 cells and exhibited a synergistic effect with L-asparaginase (L-ASNase). Mechanistically, Bis A promoted oxidative stress and apoptosis, while inhibiting autophagy, cell migration and epithelial-mesenchymal transition (EMT), impeding cancer cell development. Moreover, Bis A induced negative feedback pathways containing the GCN2-eIF2α-ATF4, PI3K-AKT-mTORC1 and RAF-MEK-ERK axes, but combination treatment of Bis A and rapamycin/torin-1 overcame the potential drug resistance triggered by mTOR pathways. Our study demonstrates that ASNS inhibition is promising for cancer chemotherapy, and Bis A is a potential lead ASNS inhibitor for anticancer development.

Analysis of alternative splicing in chicken macrophages infected with avian pathogenic E. coli (APEC)

Colibacillosis is a complex disease that caused by avian pathogenic Escherichia coli (APEC), resulting in huge economic loss to the global poultry industry and threatening to human health. Alternative splicing (AS) is a universal post-transcriptional regulatory mechanism, which can simultaneously produce many proteins from a single gene to involve in various diseases and individual development. Herein, we characterized genome-wide AS events in wild type macrophages (WT) and APEC infected macrophages (APEC) by high-throughput RNA sequencing technology. A total of 751 differentially expressed (DE) AS genes were identified in the comparison of APEC vs. WT, including 587 of SE, 114 of MXE, 25 of RI, 17 of A3 and 8 of A5 event. Functional analysis showed that these identified DE AS genes were involved in 'Endocytosis', 'p53 signaling pathway', 'MAPK signaling pathway', 'NOD-like receptor signaling pathway', 'Ubiquitin mediated proteolysis' and 'Focal adhesion' immune related pathways. In summary, we comprehensively investigate AS events during APEC infection. This study has expanded our understanding of the process of APEC infection and provided new insights for further treatment options for APEC infection.

Heterogeneity and treatment landscape of ovarian carcinoma

Ovarian carcinoma is characterized by heterogeneity at the molecular, cellular and anatomical levels, both spatially and temporally. This heterogeneity affects response to surgery and/or systemic therapy, and also facilitates inherent and acquired drug resistance. As a consequence, this tumour type is often aggressive and frequently lethal. Ovarian carcinoma is not a single disease entity and comprises various subtypes, each with distinct complex molecular landscapes that change during progression and therapy. The interactions of cancer and stromal cells within the tumour microenvironment further affects disease evolution and response to therapy. In past decades, researchers have characterized the cellular, molecular, microenvironmental and immunological heterogeneity of ovarian carcinoma. Traditional treatment approaches have considered ovarian carcinoma as a single entity. This landscape is slowly changing with the increasing appreciation of heterogeneity and the recognition that delivering ineffective therapies can delay the development of effective personalized approaches as well as potentially change the molecular and cellular characteristics of the tumour, which might lead to additional resistance to subsequent therapy. In this Review we discuss the heterogeneity of ovarian carcinoma, outline the current treatment landscape for this malignancy and highlight potentially effective therapeutic strategies in development.

Glutamine addiction and therapeutic strategies in pancreatic cancer

Pancreatic cancer remains one of the most lethal diseases worldwide owing to its late diagnosis, early metastasis, and poor prognosis. Because current therapeutic options are limited, there is an urgent need to investigate novel targeted treatment strategies. Pancreatic cancer faces significant metabolic challenges, principally hypoxia and nutrient deprivation, due to specific microenvironmental constraints, including an extensive desmoplastic stromal reaction. Pancreatic cancer cells have been shown to rewire their metabolism and energy production networks to support rapid survival and proliferation. Increased glucose uptake and glycolytic pathway activity during this process have been extensively described. However, growing evidence suggests that pancreatic cancer cells are glutamine addicted. As a nitrogen source, glutamine directly (or indirectly via glutamate conversion) contributes to many anabolic processes in pancreatic cancer, including amino acids, nucleobases, and hexosamine biosynthesis. It also plays an important role in redox homeostasis, and when converted to α-ketoglutarate, glutamine serves as an energy and anaplerotic carbon source, replenishing the tricarboxylic acid cycle intermediates. The present study aims to provide a comprehensive overview of glutamine metabolic reprogramming in pancreatic cancer, focusing on potential therapeutic approaches targeting glutamine metabolism in pancreatic cancer.

LASS2 enhances p53 protein stability and nuclear import to suppress liver cancer progression through interaction with MDM2/MDMX

LASS2 functions as a tumor suppressor in hepatocellular carcinoma (HCC), the most common type of primary liver cancer, but the underlying mechanism of its action remains largely unknown. Moreover, details on its role and the downstream mechanisms in Cholangiocarcinoma (CCA) and hepatoblastoma (HB), are rarely reported. Herein, LASS2 overexpression was found to significantly inhibit proliferation, migration, invasion and induce apoptosis in hepatoma cells with wild-type (HB cell line HepG2) and mutated p53 (HCC cell line HCCLM3 and CCA cell line HuCCT1). Gene set enrichment analysis determined the enrichment of the differentially expressed genes caused by LASS2 in the p53 signaling pathway. Moreover, the low expression of LASS2 in HCC and CCA tumor tissues was correlated with the advanced tumor-node-metastasis (TNM) stage, and the protein expression of LASS2 positively correlated with acetylated p53 (Lys373) protein levels. At least to some extent, LASS2 exerts its tumor-suppressive effects in a p53-dependent manner, in which LASS2 interacts with MDM2/MDMX and causes dual inhibition to disrupt p53 degradation by MDM2/MDMX. In addition, LASS2 induces p53 phosphorylation at ser15 and acetylation at lys373 to promote translocation from cytoplasm to nucleus. These findings provide new insights into the LASS2-induced tumor suppression mechanism in liver cancer and suggest LASS2 could serve as a potential therapeutic target for liver cancer.

Comparing P53 expression and genome-wide transcriptome profiling to Comet assay in lymphocytes from melanoma patients and healthy controls

This study compared the expression of TP53 in lymphocytes from malignant melanoma (MM) patients with positive sentinel nodes to healthy controls (HCs) following exposure to various doses of UVA radiation. The Lymphocyte Genome Sensitivity (LGS) assay indicated significant differences in DNA damage in lymphocytes between MM patients and HCs. qPCR data demonstrated an overall 3.4-fold increase in TP53 expression in lymphocytes from MM patients compared to healthy controls, following treatment with 0.5 mW/cm2 UVA radiation. Western blotting confirmed that p53 expression was increased in MM lymphocytes following UVA exposure compared to healthy individuals. Genome transcriptome profiling data displayed differences in gene expression between UVA-treated lymphocytes from MM patients and HCs. Peripheral lymphocytes from MM patients are more susceptible to the genotoxic effects of UVA compared to healthy individuals. Our previous studies showed that UVA exposure of various intensities caused significant differences in the levels of DNA damage between lymphocytes from cancer patients compared to HCs through the LGS assay. The present study's results provide further credibility to the LGS assay as a screening test for cancer detection. Peripheral lymphocytes could be a promising blood biopsy biomarker for staging of carcinomas and prevention of carcinoma progression at early stages.

Evolutionary determinants of curability in cancer

The emergence of drug-resistant cells, most of which have a mutated TP53 gene, prevents curative treatment in most advanced and common metastatic cancers of adults. Yet, a few, rarer malignancies, all of which are TP53 wild type, have high cure rates. In this Perspective, we discuss how common features of curable cancers offer insights into the evolutionary and developmental determinants of drug resistance. Acquired loss of TP53 protein function is the most common genetic change in cancer. This probably reflects positive selection in the context of strong ecosystem pressures including microenvironmental hypoxia. Loss of TP53's functions results in multiple fitness benefits and enhanced evolvability of cancer cells. TP53-null cells survive apoptosis, and tolerate potent oncogenic signalling, DNA damage and genetic instability. In addition, critically, they provide an expanded pool of self-renewing, or stem, cells, the primary units of evolutionary selection in cancer, making subsequent adaptation to therapeutic challenge by drug resistance highly probable. The exceptional malignancies that are curable, including the common genetic subtype of childhood acute lymphoblastic leukaemia and testicular seminoma, differ from the common adult cancers in originating prenatally from embryonic or fetal cells that are developmentally primed for TP53-dependent apoptosis. Plus, they have other genetic and phenotypic features that enable dissemination without exposure to selective pressures for TP53 loss, retaining their intrinsic drug hypersensitivity.

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.

Proximal Tubular Lats2 Ablation Exacerbates Ischemia/Reperfusion Injury (IRI)-Induced Renal Maladaptive Repair through the Upregulation of P53

The Hippo pathway mediates renal maladaptive repair after acute kidney injury (AKI), which has been considered a driving force in the progression to chronic kidney disease (CKD). LATS2, a core kinase of the Hippo pathway, exerts non-Hippo-dependent functions in the regulation of the cell cycle and cell fate, providing new insights into AKI and further repair. However, its role remains unknown. Here, we utilized a proximal tubular Lats2 conditional knockout mouse strain (Lats2-CKO) to evaluate the effect of LATS2 deficiency on ischemia/reperfusion-induced AKI-to-CKD transition. Lats2-CKO mice presented with more severe tubular maladaptive repair, inflammatory infiltration, interstitial fibrosis, and apoptosis following AKI. Importantly, we discovered that Lats2 ablation caused the activation of p53, with increased levels of cellular apoptotic molecules (p21, Bax, and cleaved caspase-3), and decreased levels of anti-apoptotic molecules (Bcl-2 and Bcl-xL). Pifithirin-α (p53 inhibitor) effectively attenuated renal fibrosis, inflammation, and apoptosis in Lats2-CKO mice after AKI. Consistently, in vitro Lats2 overexpression decreased p53, p21, Bax and cleaved caspase 3 expression after hypoxia/reoxygenation (H/R) treatment. Of note, the phosphorylation of MDM2, which promotes the ubiquitination degradation of p53, at site Ser186 was decreased in Lats2-CKO kidneys, but increased by Lats2 overexpression in vitro. Therefore, LATS2 deficiency aggravated ischemia/reperfusion injury (IRI)-induced maladaptive repair via regulating the tubular MDM2-p53 axis in AKI-to-CKD transition.

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.

Regulation of Tumor Apoptosis of Poriae cutis-Derived Lanostane Triterpenes by AKT/PI3K and MAPK Signaling Pathways In Vitro

Poria cocos is traditionally used as both food and medicine. Triterpenoids in Poria cocos have a wide range of pharmacological activities, such as diuretic, sedative and tonic properties. In this study, the anti-tumor activities of poricoic acid A (PAA) and poricoic acid B (PAB), purified by high-speed counter-current chromatography, as well as their mechanisms and signaling pathways, were investigated using a HepG2 cell model. After treatment with PAA and PAB on HepG2 cells, the apoptosis was obviously increased (p < 0.05), and the cell cycle arrested in the G2/M phase. Studies showed that PAA and PAB can also inhibit the occurrence and development of tumor cells by stimulating the generation of ROS in tumor cells and inhibiting tumor migration and invasion. Combined Polymerase Chain Reaction and computer simulation of molecular docking were employed to explore the mechanism of tumor proliferation inhibition by PAA and PAB. By interfering with phosphatidylinositol-3-kinase/protein kinase B, Mitogen-activated protein kinases and p53 signaling pathways; and further affecting the expression of downstream caspases; matrix metalloproteinase family, cyclin-dependent kinase -cyclin, Intercellular adhesion molecules-1, Vascular Cell Adhesion Molecule-1 and Cyclooxygenase -2, may be responsible for their anti-tumor activity. Overall, the results suggested that PAA and PAB induced apoptosis, halted the cell cycle, and inhibited tumor migration and invasion through multi-pathway interactions, which may serve as a potential therapeutic agent against cancer.

Research progress on multiple cell death pathways of podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease, and its clinical manifestations are progressive proteinuria, decreased glomerular filtration rate, and renal failure. The injury and death of glomerular podocytes are the keys to DKD. Currently, a variety of cell death modes have been identified in podocytes, including apoptosis, autophagy, endoplasmic reticulum (ER) stress, pyroptosis, necroptosis, ferroptosis, mitotic catastrophe, etc. The signaling pathways leading to these cell death processes are interconnected and can be activated simultaneously or in parallel. They are essential for cell survival and death that determine the fate of cells. With the deepening of the research on the mechanism of cell death, more and more researchers have devoted their attention to the underlying pathologic research and the drug therapy research of DKD. In this paper, we discussed the podocyte physiologic role and DKD processes. We also provide an overview of the types and specific mechanisms involved in each type of cell death in DKD, as well as related targeted therapy methods and drugs are reviewed. In the last part we discuss the complexity and potential crosstalk between various modes of cell death, which will help improve the understanding of podocyte death and lay a foundation for new and ideal targeted therapy strategies for DKD treatment in the future.

Ferroptosis: An Emerging Target for Bladder Cancer Therapy

Bladder cancer (BC), as one of the main urological cancers in the world, possesses the abilities of multiple-drug resistance and metastasis. However, there remains a significant gap in the understanding and advancement of prognosis and therapeutic strategies for BC. Ferroptosis, a novel type of iron-dependent regulated cell death, depends on lipid peroxidation, which has been proven to have a strong correlation with the development and treatment of BC. Its mechanism mainly includes three pathways, namely, lipid peroxidation, the antioxidant system, and the iron overload pathway. In this review, we reviewed the mechanism of ferroptosis, along with the related therapeutic targets and drugs for BC, as it might become a new anticancer treatment in the future.

A NRF2-induced secretory phenotype activates immune surveillance to remove irreparably damaged cells

While it is well established that the KEAP1-NRF2 pathway regulates the main inducible cellular response to oxidative stress, this cytoprotective function of NRF2 could become deleterious to the host if it confers survival onto irreparably damaged cells. In this regard, we have found that in diseased states, NRF2 promotes the transcriptional activation of a specific subset of the senescence-associated secretory phenotype (SASP) gene program, which we have named the NRF2-induced secretory phenotype (NISP). In two models of hepatic disease using Pten::Keap1 and Keap1::Atg7 double knockout mice, we found that the NISP functions in the liver to recruit CCR2 expressing monocytes, which function as immune system effector cells to directly remove the damaged cells. Through activation of this immune surveillance pathway, in non-transformed cells, NRF2 functions as a tumour suppressor to mitigate the long-term survival of damaged cells which otherwise would be detrimental for host survival. This pathway represents the final stage of the oxidative stress response, as it allows cells to be safely removed if the macromolecular damage caused by the original stressor is so extensive that it is beyond the repair capacity of the cell.

Tumor suppressor Parkin induces p53-mediated cell cycle arrest in human lung and colorectal cancer cells

Dysregulation of the E3 ubiquitin ligase Parkin has been linked to various human cancers, indicating that Parkin is a tumor suppressor protein. However, the mechanisms of action of Parkin remain unclear to date. Thus, we aimed to elucidate the mechanisms of action of Parkin as a tumor suppressor in human lung and colorectal cancer cells. Results showed that Parkin overexpression reduced the viability of A549 human lung cancer cells by inducing G2/M cell cycle arrest. In addition, Parkin caused DNA damage and ATM (Ataxia telangiectasia mutated) activation, which subsequently led to p53 activation. It also induced the p53-mediated upregulation of p21 and downregulation of cyclin B1. Moreover, Parkin suppressed the proliferation of HCT-15 human colorectal cancer cells by a mechanism similar to that in A549 lung cancer cells. Taken together, our results suggest that the tumor-suppressive effects of Parkin on lung and colorectal cancer cells are mediated by DNA damage/p53 activation/cyclin B1 reduction/cell cycle arrest. [BMB Reports 2023; 56(10): 557-562].

Anti-cancer potential of selenium-chitosan-polyethylene glycol-carvacrol nanocomposites in multiple myeloma U266 cells

Multiple myeloma (MM) is an incurable cancer that is characterized by malignant plasma cell proliferation. Approximately 10% of all blood cancers are MM, and there is no standard curative therapy. In this work, we intended to synthesize, characterize, and assess the anticancer effects of selenium/chitosan/polyethylene glycol-carvacrol nanocomposites (SCP-Car-NCs) on MM U266 cells in vitro. Various characterization techniques were used to characterize the synthesized SCP-Car-NCs. Several in vitro free radical scavenging experiments were conducted to test the ability of synthesized SCP-Car-NCs to scavenge the different free radicals. The cytotoxicity of SCP-Car-NCs was assessed on Vero and U266 cells using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. By using various fluorescence staining techniques, the amount of reactive oxygen species (ROS) generation, MMP, and apoptosis were measured. Using commercial test kits, the levels of oxidative stress and apoptotic biomarkers in control and treated U266 cells were assessed. The highest peak in the UV spectral analysis was found to be at 271 nm, demonstrating the development of SCP-Car-NCs. Fourier transform infrared analysis showed that the synthesized SCP-Car-NCs contained a variety of stretching and bonding. The X-ray diffraction study confirmed the crystallinity of SCP-Car-NCs. The dynamic light scattering analysis showed that the SCP-Car-NCs had an average size of 171 nm. The different free radicals, such as the 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and peroxyl radicals, were significantly scavenged by the SCP-Car-NCs. According to the MTT assay results, the SCP-Car-NCs decreased the viability of U266 cells while having no impact on the proliferation of Vero cells. The SCP-Car-NCs significantly boosted ROS production, decreased the MMP level, and promoted apoptosis, as evidenced by the fluorescence staining experiments. In U266 cells treated with SCP-Car-NCs, the level of thiobarbituric acid reactive substances increased while superoxide dismutases and glutathione levels were reduced. In the SCP-Car-NCs treated U266 cells, it was found that the Bax, caspase-3, and -9 activities had increased while the Bcl-2 level had decreased. In conclusion, our findings show that SCP-Car-NCs treatment reduced the viability and increased apoptosis in the U266 cells, providing a new insight on SCP-Car-NCs' potential for usage in the future to treat MM.

Multidimensional quantitative phenotypic and molecular analysis reveals neomorphic behaviors of p53 missense mutants

Mutations in the TP53 tumor suppressor gene occur in >80% of the triple-negative or basal-like breast cancer. To test whether neomorphic functions of specific TP53 missense mutations contribute to phenotypic heterogeneity, we characterized phenotypes of non-transformed MCF10A-derived cell lines expressing the ten most common missense mutant p53 proteins and observed a wide spectrum of phenotypic changes in cell survival, resistance to apoptosis and anoikis, cell migration, invasion and 3D mammosphere architecture. The p53 mutants R248W, R273C, R248Q, and Y220C are the most aggressive while G245S and Y234C are the least, which correlates with survival rates of basal-like breast cancer patients. Interestingly, a crucial amino acid difference at one position-R273C vs. R273H-has drastic changes on cellular phenotype. RNA-Seq and ChIP-Seq analyses show distinct DNA binding properties of different p53 mutants, yielding heterogeneous transcriptomics profiles, and MD simulation provided structural basis of differential DNA binding of different p53 mutants. Integrative statistical and machine-learning-based pathway analysis on gene expression profiles with phenotype vectors across the mutant cell lines identifies quantitative association of multiple pathways including the Hippo/YAP/TAZ pathway with phenotypic aggressiveness. Further, comparative analyses of large transcriptomics datasets on breast cancer cell lines and tumors suggest that dysregulation of the Hippo/YAP/TAZ pathway plays a key role in driving the cellular phenotypes towards basal-like in the presence of more aggressive p53 mutants. Overall, our study describes distinct gain-of-function impacts on protein functions, transcriptional profiles, and cellular behaviors of different p53 missense mutants, which contribute to clinical phenotypic heterogeneity of triple-negative breast tumors.

Syzygium cumini (L.) Extract-Derived Green Titanium Dioxide Nanoparticles Induce Caspase-Dependent Apoptosis in Hepatic Cancer Cells

An aqueous extract of Syzygium cumini seeds was utilized to green synthesize titanium dioxide nanoparticles (TiO2 NPs). UV-Visible, DLS, FTIR, XRD, FESEM, TEM, SAED, EDAX, and photoluminescence spectroscopy techniques were employed to characterize the prepared TiO2 nanoparticles. The rutile crystal structure of TiO2 NPs was revealed by XRD study. The TEM and FESEM images of the TiO2 NPs revealed an average particle size of 50-100 nm. We employed EDAX to investigate the elemental compositions of TiO2 NPs. The O-Ti-O stretching bands appeared in the FTIR spectrum of TiO2 NPs at wavenumbers of 495 cm-1. The absorption edge peaks of TiO2 NPs were found in the UV-vis spectra at 397 nm. The MTT study revealed that TiO2 NPs effectively inhibited the growth of liver cancer Hep3 and Hep-G2 cells. The results of the corresponding fluorescent staining assays showed that TiO2 NPs significantly increased ROS generation, decreased MMP, and induced apoptosis in both liver cancer Hep3 and Hep-G2 cells. TiO2 nanoparticles lessened SOD, CAT, and GSH levels while augmenting MDA contents in Hep3 and Hep-G2 cells. In both Hep3 and Hep-G2 cells treated with TiO2 NPs, the Bax, CytC, p53, caspase-3, -8, and -9 expressions were remarkably augmented, while Bcl-2 expression was reduced. Overall, these findings revealed that formulated TiO2 NPs treatment considerably inhibited growth and triggered apoptosis in Hep3 and HepG2 cells.

TP53 R249S mutation in hepatic organoids captures the predisposing cancer risk

BACKGROUND AND AIMS

Major genomic drivers of hepatocellular carcinoma (HCC) are nowadays well recognized, although models to establish their roles in human HCC initiation remain scarce. Here, we used human liver organoids in experimental systems to mimic the early stages of human liver carcinogenesis from the genetic lesions of TP53 loss and L3 loop R249S mutation. In addition, chromatin immunoprecipitation sequencing (ChIP-seq) of HCC cell lines shed important functional insights into the initiation of HCC consequential to the loss of tumor-suppressive function from TP53 deficiency and gain-of-function activities from mutant p53.

APPROACH AND RESULTS

Human liver organoids were generated from surgical nontumor liver tissues. CRISPR knockout of TP53 in liver organoids consistently demonstrated tumor-like morphological changes, increased in stemness and unrestricted in vitro propagation. To recapitulate TP53 status in human HCC, we overexpressed mutant R249S in TP53 knockout organoids. A spontaneous increase in tumorigenic potentials and bona fide HCC histology in xenotransplantations were observed. ChIP-seq analysis of HCC cell lines underscored gain-of-function properties from L3 loop p53 mutants in chromatin remodeling and overcoming extrinsic stress. More importantly, direct transcriptional activation of PSMF1 by mutant R249S could increase organoid resistance to endoplasmic reticulum stress, which was readily abrogated by PSMF1 knockdown in rescue experiments. In a patient cohort of primary HCC tumors and genome-edited liver organoids, quantitative polymerase chain reaction corroborated ChIP-seq findings and verified preferential genes modulated by L3 mutants, especially those enriched by R249S.

CONCLUSIONS

We showed differential tumorigenic effects from TP53 loss and L3 mutations, which together confer normal hepatocytes with early clonal advantages and prosurvival functions.

Design, synthesis, and biological evaluation of furan-bearing pyrazolo[3,4-b]pyridines as novel inhibitors of CDK2 and P53-MDM2 protein-protein interaction

The novel series of furan-bearing pyrazolo[3,4-b]pyridines were designed as cyclin-dependent kinase 2 (CDK2) inhibitors and as p53-murine double minute 2 (MDM2) inhibitors. The newly synthesized compounds were screened for their antiproliferative activity toward hepatocellular carcinoma (HepG2) and breast cancer (MCF7) cell lines. The most active compounds on both cell lines were additionally evaluated for their in vitro CDK2 inhibitory activity. Compounds 7b and 12f displayed enhanced activity (half-maximal inhibitory concentration [IC50 ] = 0.46 and 0.27 µM, respectively) in comparison to the standard roscovitine (IC50  = 1.41 ± 0.03 µM), in addition to, cell cycle arrest at S phase and G1/S transition phase in MCF7 cells treated with both compounds, respectively. Moreover, the most active spiro-oxindole derivative against MCF7 cell line, 16a, exhibited enhanced inhibitory activity against p53-MDM2 interaction in vitro (IC50  = 3.09 ± 0.12 µM) compared to nutlin, and increased the levels of both p53 and p21 by nearly fourfold in comparison to the negative control. Molecular docking studies demonstrated the plausible interaction patterns of the most potent derivatives 17b and 12f in the CDK2 binding pocket and the spiro-oxindole 16a with p53-MDM2 complex, respectively. Consequently, the new chemotypes 7b, 12f, and 16a can be presented as promising antitumor hits for further studies and optimization.

CRISPR single base-editing: in silico predictions to variant clonal cell lines

Engineering single base edits using CRISPR technology including specific deaminases and single-guide RNA (sgRNA) is a rapidly evolving field. Different types of base edits can be constructed, with cytidine base editors (CBEs) facilitating transition of C-to-T variants, adenine base editors (ABEs) enabling transition of A-to-G variants, C-to-G transversion base editors (CGBEs) and recently adenine transversion editors (AYBE) that create A-to-C and A-to-T variants. The base-editing machine learning algorithm BE-Hive predicts which sgRNA and base editor combinations have the strongest likelihood of achieving desired base edits. We have used BE-Hive and TP53 mutation data from The Cancer Genome Atlas (TCGA) ovarian cancer cohort to predict which mutations can be engineered, or reverted to wild-type (WT) sequence, using CBEs, ABEs or CGBEs. We have developed and automated a ranking system to assist in selecting optimally designed sgRNA that considers the presence of a suitable protospacer adjacent motif (PAM), the frequency of predicted bystander edits, editing efficiency and target base change. We have generated single constructs containing ABE or CBE editing machinery, an sgRNA cloning backbone and an enhanced green fluorescent protein tag (EGFP), removing the need for co-transfection of multiple plasmids. We have tested our ranking system and new plasmid constructs to engineer the p53 mutants Y220C, R282W and R248Q into WT p53 cells and shown that these mutants cannot activate four p53 target genes, mimicking the behaviour of endogenous p53 mutations. This field will continue to rapidly progress, requiring new strategies such as we propose to ensure desired base-editing outcomes.

Network pharmacology prediction and experimental verification of Rhubarb-Peach Kernel promoting apoptosis in endometriosis

BACKGROUND

"Rhubarb-Peach Kernel" herb pair (RP) one of the most frequently used drug pairs, has been used in traditional medicine in China to treat inflammation and diseases associated with pain. Although it is widely used clinically and has a remarkable curative effect, the mechanism of RP treatment for endometriosis (EMs) remains unclear due to its complicated components. The aim of this study was to investigate the anti-endometriosis effect of RP, with emphasis on apoptosis via network pharmacology prediction, molecular docking and experimental verification.

METHODS

The related ingredients and targets of RP in treating EMs were screened out using Traditional Chinese Medicine Systems Pharmacology (TCMSP), Tool for Molecular mechanism of Traditional Chinese Medicine (BATMAN-TCM), and GeneCards database. The data of the protein-protein interaction (PPI) network was obtained by the Search Tool for the Retrieval of Interaction Gene/Proteins (STRING) Database. The Metascape database was adopt for Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis. After that, the molecular docking of the main active ingredients and apoptosis targets was performed. Finally, the pro-apoptotic effect of RP was verified in hEM15a cells.

RESULTS

A total of 32 RP compounds were collected. Forty-two matching targets were picked out as the correlative targets of RP in treating EMs. Among these, 18 hub targets including P53, CASP3 were recognized by the PPI network. KEGG enrichment analysis discovered that the regulation of apoptosis was one of the potential mechanisms of RP against EMs. Anthraquinone compounds, flavonoids, and triterpenes in RP were identified as crucial active ingredients, involved in the pro-apoptotic effect, which were confirmed subsequently by molecular docking. Additionally, it was verified that RP treatment promoted apoptosis and inhibited the proliferation of EMs cells (assessed by MTT and Flow cytometry). Moreover, the induction of apoptosis in treated EMs cells may be due to the regulation of apoptosis-related protein expression, including P53, BAX, and CASP3.

CONCLUSIONS

The results of our study demonstrated that RP may exert its therapeutic effects on EMs through the potential mechanism of promoting apoptosis. Anthraquinones, flavonoids and triterpenoids are the possible pro-apoptotic components in RP.

The diversified role of mitochondria in ferroptosis in cancer

Ferroptosis is a form of regulated cell death induced by iron-dependent lipid peroxidation, and it has been studied extensively since its discovery in 2012. Induced by iron overload and ROS accumulation, ferroptosis is modulated by various cellular metabolic and signaling pathways. The GSH-GPX4 pathway, the FSP1-CoQ10 pathway, the GCH1-BH4 pathway, the DHODH-CoQH2 system and the sex hormones suppress ferroptosis. Mitochondrial iron metabolism regulates ferroptosis and mitochondria also undergo a morphological change during ferroptosis, these changes include increased membrane density and reduced mitochondrial cristae. Moreover, mitochondrial energy metabolism changes during ferroptosis, the increased oxidative phosphorylation and ATP production rates lead to a decrease in the glycolysis rate. In addition, excessive oxidative stress induces irreversible damage to mitochondria, diminishing organelle integrity. ROS production, mitochondrial membrane potential, mitochondrial fusion and fission, and mitophagy also function in ferroptosis. Notably, some ferroptosis inhibitors target mitochondria. Ferroptosis is a major mechanism for cell death associated with the progression of cancer. Metastasis-prone or metastatic cancer cells are more susceptible to ferroptosis. Inducing ferroptosis in tumor cells shows very promising potential for treating drug-resistant cancers. In this review, we present a brief retrospect of the discovery and the characteristics of ferroptosis, then we discuss the regulation of ferroptosis and highlight the unique role played by mitochondria in the ferroptosis of cancer cells. Furthermore, we explain how ferroptosis functions as a double-edged sword as well as novel therapies aimed at selectively manipulating cell death for cancer eradication.

LSD1 promotes prostate cancer reprogramming by repressing TP53 signaling independently of its demethylase function

Lysine-specific demethylase 1 (LSD1) is a histone demethylase that promotes stemness and cell survival in cancers such as prostate cancer. Most prostate malignancies are adenocarcinomas with luminal differentiation. However, some tumors undergo cellular reprogramming to a more lethal subset termed neuroendocrine prostate cancer (NEPC) with neuronal differentiation. The frequency of NEPC is increasing since the widespread use of potent androgen receptor signaling inhibitors. Currently, there are no effective treatments for NEPC. We previously determined that LSD1 promotes survival of prostate adenocarcinoma tumors. However, the role of LSD1 in NEPC is unknown. Here, we determined that LSD1 is highly upregulated in NEPC versus adenocarcinoma patient tumors. LSD1 suppression with RNAi or allosteric LSD1 inhibitors - but not catalytic inhibitors - reduced NEPC cell survival. RNA-Seq analysis revealed that LSD1 represses pathways linked to luminal differentiation, and TP53 was the top reactivated pathway. We confirmed that LSD1 suppressed the TP53 pathway by reducing TP53 occupancy at target genes while LSD1's catalytic function was dispensable for this effect. Mechanistically, LSD1 inhibition disrupted LSD1-HDAC interactions, increasing histone acetylation at TP53 targets. Finally, LSD1 inhibition suppressed NEPC tumor growth in vivo. These findings suggest that blocking LSD1's noncatalytic function may be a promising treatment strategy for NEPC.

Differential Modulation of the Phosphoproteome by the MAP Kinases Isoforms p38α and p38β

The p38 members of the mitogen-activated protein kinases (MAPKs) family mediate various cellular responses to stress conditions, inflammatory signals, and differentiation factors. They are constitutively active in chronic inflammatory diseases and some cancers. The differences between their transient effects in response to signals and the chronic effect in diseases are not known. The family is composed of four isoforms, of which p38α seems to be abnormally activated in diseases. p38α and p38β are almost identical in sequence, structure, and biochemical and pharmacological properties, and the specific unique effects of each of them, if any, have not yet been revealed. This study aimed to reveal the specific effects induced by p38α and p38β, both when transiently activated in response to stress and when chronically active. This was achieved via large-scale proteomics and phosphoproteomics analyses using stable isotope labeling of two experimental systems: one, mouse embryonic fibroblasts (MEFs) deficient in each of these p38 kinases and harboring either an empty vector or vectors expressing p38αWT, p38βWT, or intrinsically active variants of these MAPKs; second, induction of transient stress by exposure of MEFs, p38α-/-, and p38β-/- MEFs to anisomycin. Significant differences in the repertoire of the proteome and phosphoproteome between cells expressing active p38α and p38β suggest distinct roles for each kinase. Interestingly, in both cases, the constitutive activation induced adaptations of the cells to the chronic activity so that known substrates of p38 were downregulated. Within the dramatic effect of p38s on the proteome and phosphoproteome, some interesting affected phosphorylation sites were those found in cancer-associated p53 and Hspb1 (HSP27) proteins and in cytoskeleton-associated proteins. Among these, was the stronger direct phosphorylation by p38α of p53-Ser309, which was validated on the Ser315 in human p53. In summary, this study sheds new light on the differences between chronic and transient p38α and p38β signaling and on the specific targets of these two kinases.

Genes of Predisposition to Childhood Beta-Cell Acute Lymphoblastic Leukemia in the Kazakh Population

BACKGROUND

Today, acute lymphoblastic leukemia is one of the most common malignant diseases of the hematopoietic system. The genetic predisposition to ALL is not fully explored in various ethnic populations.

OBJECTIVE

The study aimed to conduct a comparative analysis of the population frequencies of alleles and genotypes of polymorphic gene variants: immune regulation GATA3 (rs3824662); transcription and differentiation of B cells: ARID5B (rs7089424, rs10740055), IKZF1 (rs4132601); differentiation of hematopoietic cells: PIP4K2A (rs7088318); apoptosis: CEBPE (rs2239633), tumor suppressors: CDKN2A (rs3731249), TP53 (rs1042522); carcinogen metabolism: CBR3 (rs1056892), CYP1A1 (rs104894, rs4646903), according to genome-wide association studies analyses associated with the risk of developing pediatric beta-cell acute lymphoblastic leukemia (B-cell ALL), in an ethnically homogeneous population of Kazakhs with studied populations.

METHODS

The genomic database consists of 1800 conditionally healthy persons of Kazakh nationality, genotyped using OmniChip 2.5-8 Illumina chips at the deCODE genetics as part of the InterPregGen 7 project of the European Union (EU) framework program under Grant Agreement No. 282540.

RESULTS

High population frequencies of single nucleotide polymorphism (SNP) minor alleles identified for immune regulation genes - GATA3 rs3824662 - 42.5%; transcription and differentiation of B-cells genes - ARID5B rs7089424 - 33.1% and rs10740055 - 48.5%, which suggests their significant genetic contribution to the risk of development and prognosis of the effectiveness of B-cell ALL therapy in the Kazakh population. The significantly lower population frequency of the minor allele G rs1056892 CBR3 gene - 38.6% in the Kazakhs suggests its significant protective effect in reducing the risk of childhood B-cell ALL and the smaller number of cardiac complications after anthracycline therapy.

CONCLUSION

The obtained results will serve as a basis for developing effective methods for predicting the risk of development, early diagnosis, and effectiveness of treatment of B-cell ALL in children.

p53 restoration in small cell lung cancer identifies a latent cyclophilin-dependent necrosis mechanism

The p53 tumor suppressor regulates multiple context-dependent tumor suppressive programs. Although p53 is mutated in ~90% of small cell lung cancer (SCLC) tumors, how p53 mediates tumor suppression in this context is unknown. Here, using a mouse model of SCLC in which endogenous p53 expression can be conditionally and temporally regulated, we show that SCLC tumors maintain a requirement for p53 inactivation. However, we identify tumor subtype heterogeneity between SCLC tumors such that p53 reactivation induces senescence in a subset of tumors, while in others, p53 induces necrosis. We pinpoint cyclophilins as critical determinants of a p53-induced transcriptional program that is specific to SCLC tumors and cell lines poised to undergo p53-mediated necrosis. Importantly, inhibition of cyclophilin isomerase activity, or genetic ablation of specific cyclophilin genes, suppresses p53-mediated necrosis by limiting p53 transcriptional output without impacting p53 chromatin binding. Our study demonstrates that intertumoral heterogeneity in SCLC influences the biological response to p53 restoration, describes a cyclophilin-dependent mechanism of p53-regulated cell death, and uncovers putative mechanisms for the treatment of this most-recalcitrant tumor type.

Targeting mutant p53 stabilization for cancer therapy

Over 50% cancer bears TP53 mutation, the highly stabilized mutant p53 protein drives the tumorigenesis and progression. Mutation of p53 not only cause loss-of-function and dominant-negative effects (DNE), but also results in the abnormal stability by the regulation of the ubiquitin-proteasome system and molecular chaperones that promote tumorigenesis through gain-of-function effects. The accumulation of mutant p53 is mainly regulated by molecular chaperones, including Hsp40, Hsp70, Hsp90 and other biomolecules such as TRIM21, BAG2 and Stat3. In addition, mutant p53 forms prion-like aggregates or complexes with other protein molecules and result in the accumulation of mutant p53 in tumor cells. Depleting mutant p53 has become one of the strategies to target mutant p53. This review will focus on the mechanism of mutant p53 stabilization and discuss how the strategies to manipulate these interconnected processes for cancer therapy.

TRIP 13-dependent pathways promote the development of gastric cancer

TRIP13 is highly expressed in various human tumors and promotes tumorigenesis. We aimed to explore the biological effect of TRIP13 on gastric cancer. The RNA sequence data were retrieved from TCGA to evaluate TRIP13 mRNA expression in gastric cancer. Paired formalin-fixed paraffin-embedded blocks were further analyzed to verify the relationship between TRIP13 expression and carcinogenic status. The functions of TRIP13 on the proliferation of gastric malignancy were investigated by MTT, flow cytometry, colony formation experiment, and nude mouse tumor formation experiment. Finally, microarray analysis of TRIP13-related pathways was performed to identify the potential underlying mechanism of TRIP13 in gastric cancer. TRIP13 was found to have high expression in tumor samples. TRIP13 expression status was significantly subjective to tumor-node-metastasis (TNM) staging and poor survival. The downregulation of TRIP13 promoted apoptosis and inhibited tumor growth. TRIP13-dependent JAK/STAT and NF-κB signaling cascade were found as two key pathways in the carcinogenesis of GC. In conclusion, TRIP13 participates in the carcinogenesis of stomach cancer, and its overexpression in the cancerous tissues dovetail with advanced stage and survival. Moreover, TRIP13 functions as an upstream regulator of the JAK/STAT and p53 signaling pathways, which play critical roles in developing various malignancies.

P53 status, and G2/M cell cycle arrest, are determining factors in cell-death induction mediated by ELF-EMF in glioblastoma

The average survival of patients with glioblastoma is 12-15 months. Therefore, finding a new treatment method is important, especially in cases that show resistance to treatment. Extremely low-frequency electromagnetic fields (ELF-EMF) have characteristics and capabilities that can be proposed as a new cancer treatment method with low side effects. This research examines the antitumor effect of ELF-EMF on U87 and U251 glioblastoma cell lines. Flowcytometry determined the viability/apoptosis and distribution of cells in different phases of the cell cycle. The size of cells was assessed by TEM. Important cell cycle regulation genes mRNA expression levels were investigated by real-time PCR. ELF-EMF induced apoptosis in U87cells much more than U251 (15% against 2.43%) and increased G2/M cell population in U87 (2.56%, p value < 0.05), and S phase in U251 (2.4%) (data are normalized to their sham exposure). The size of U87 cells increased significantly after ELF-EMF exposure (overexpressing P53 in U251 cells increased the apoptosis induction by ELF-EMF). The expression level of P53, P21, and MDM2 increased and CCNB1 decreased in U87. Among the studied genes, MCM6 expression decreased in U251. Increasing expression of P53, P21 and decreasing CCNB1, induction of cell G2/M cycle arrest, and consequently increase in the cell size can be suggested as one of the main mechanisms of apoptosis induction by ELF-EMF; furthermore, our results demonstrate the possible footprint of P53 in the apoptosis induction by ELF-EMF, as U87 carry the wild type of P53 and U251 has the mutated form of this gene.

Alternatively mechanistic insights into acetylation in p53-mediated transcriptional regulation of cancer cell-intrinsic PD-1

Since the recent discovery of cancer cell-intrinsic programmed cell death protein-1 (PD-1), the mechanisms that manipulate PD-1 functions in tumor development beyond its immune checkpoint roles have become attractive research topics in oncology. Our previous study validated that PD-1 exists in lung cancer cells and is directly transactivated by p53 in a DNA-binding domain (DBD) acetylation-dependent manner. Here, we report that the carboxyl-terminal domain (CTD) of p53 likewise participates in PD-1 transcriptional regulation in cancer cells under different regulatory mechanisms. By mutating the lysine residues within the CTD to mimic either acetylation-deficient or fully acetylated status, we proved that acetylated CTD dramatically impeded p53-mediated transactivation of PD-1. Furthermore, we identified bromodomain-containing protein 4 (BRD4) as a transcriptional coactivator of p53 that facilitates p53-mediated PD-1 transcription. Mechanistically, BRD4 specifically bound to the unacetylated CTD of p53, while CTD acetylation almost completely destroyed the BRD4-p53 interaction and thus led to compromised PD-1 expression. Collectively, this study unveils an alternative mechanism of p53 acetylation-directed PD-1 transcriptional regulation, which would broaden our current understanding of the molecular regulatory network of cancer cell-intrinsic PD-1.

Overcoming therapeutic resistance in pancreatic cancer: Emerging opportunities by targeting BRCAs and p53

Pancreatic cancer (PC) is characterized by (epi)genetic and microenvironmental alterations that negatively impact the treatment outcomes. New targeted therapies have been pursued to counteract the therapeutic resistance in PC. Aiming to seek for new therapeutic options for PC, several attempts have been undertaken to exploit BRCA1/2 and TP53 deficiencies as promising actionable targets. The elucidation of the pathogenesis of PC highlighted the high prevalence of p53 mutations and their connection with the aggressiveness and therapeutic resistance of PC. Additionally, PC is associated with dysfunctions in several DNA repair-related genes, including BRCA1/2, which sensitize tumours to DNA-damaging agents. In this context, poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) were approved for mutant BRCA1/2 PC patients. However, acquired drug resistance has become a major drawback of PARPi. This review emphasizes the importance of targeting defective BRCAs and p53 pathways for advancing personalized PC therapy, with particular focus on how this approach may provide an opportunity to tackle PC resistance.

SCML2 contributes to tumor cell resistance to DNA damage through regulating p53 and CHK1 stability

SCML2 has been found to be highly expressed in various tumors. However, the extent to which SCML2 is involved in tumorigenesis and cancer therapy is yet to be fully understood. In this study, we aimed to investigate the relationship between SCML2 and DNA damage response (DDR). Firstly, DNA damage stabilizes SCML2 through CHK1-mediated phosphorylation at Ser570. Functionally, this increased stability of SCML2 enhances resistance to DNA damage agents in p53-positive, p53-mutant, and p53-negative cells. Notably, SCML2 promotes chemoresistance through distinct mechanisms in p53-positive and p53-negative cancer cells. SCML2 binds to the TRAF domain of USP7, and Ser441 is a critical residue for their interaction. In p53-positive cancer cells, SCML2 competes with p53 for USP7 binding and destabilizes p53, which prevents DNA damage-induced p53 overactivation and increases chemoresistance. In p53-mutant or p53-negative cancer cells, SCML2 promotes CHK1 and p21 stability by inhibiting their ubiquitination, thereby enhancing the resistance to DNA damage agents. Interestingly, we found that SCML2A primarily stabilizes CHK1, while SCML2B regulates the stability of p21. Therefore, we have identified SCML2 as a novel regulator of chemotherapy resistance and uncovered a positive feedback loop between SCML2 and CHK1 after DNA damage, which serves to promote the chemoresistance to DNA damage agents.

Medical Needs and Therapeutic Options for Melanoma Patients Resistant to Anti-PD-1-Directed Immune Checkpoint Inhibition

Available 4- and 5-year updates for progression-free and for overall survival demonstrate a lasting clinical benefit for melanoma patients receiving anti-PD-directed immune checkpoint inhibitor therapy. However, at least one-half of the patients either do not respond to therapy or relapse early or late following the initial response to therapy. Little is known about the reasons for primary and/or secondary resistance to immunotherapy and the patterns of relapse. This review, prepared by an interdisciplinary expert panel, describes the assessment of the response and classification of resistance to PD-1 therapy, briefly summarizes the potential mechanisms of resistance, and analyzes the medical needs of and therapeutic options for melanoma patients resistant to immune checkpoint inhibitors. We appraised clinical data from trials in the metastatic, adjuvant and neo-adjuvant settings to tabulate frequencies of resistance. For these three settings, the role of predictive biomarkers for resistance is critically discussed, as well as are multimodal therapeutic options or novel immunotherapeutic approaches which may help patients overcome resistance to immune checkpoint therapy. The lack of suitable biomarkers and the currently modest outcomes of novel therapeutic regimens for overcoming resistance, most of them with a PD-1 backbone, support our recommendation to include as many patients as possible in novel or ongoing clinical trials.