Post-Transcriptional Regulation of Anti-Apoptotic BCL2 Family Members. Int J Mol Sci. 2018;19:308. [PMID: 29361709 PMCID: PMC5796252 DOI: 10.3390/ijms19010308]

The role of Bcl‑2 in controlling the transition between autophagy and apoptosis (Review)

The Bcl‑2 protein family serves a key role in maintaining cellular homeostasis by regulating the balance between autophagy and apoptosis. The present review aimed to summarize interactions of Bcl‑2 with key proteins, including Beclin 1, Bax and Bcl‑2 homologous antagonist/killer, as well as its influence on cellular processes such as mitophagy, nutrient sensing and endoplasmic reticulum stress response. The impact of post‑translational modifications of Bcl‑2, including phosphorylation, ubiquitination and sumoylation, is discussed with respect to their regulatory roles under stress. In pathological states, Bcl‑2 upregulation in cancer suppresses apoptosis and autophagy, thereby facilitating tumor survival and resistance to chemotherapy. Conversely, in neurodegenerative diseases, impaired autophagy and increased apoptosis contribute to neuronal loss. Therapeutic strategies targeting Bcl‑2 (for example inhibitors such as venetoclax, navitoclax, obatoclax and combination therapies involving autophagy modulators) were evaluated for their potential efficacy. There is lack of understanding of tissue‑specific functions of Bcl‑2 and its interactions with non‑coding RNAs. Future research should prioritize these areas and leverage advanced single‑cell technologies to elucidate the real‑time dynamics of Bcl‑2 in cell processes. The present review highlights the key role of Bcl‑2 in cell fate determination and highlights its potential as a therapeutic target, offering insight for the development of innovative treatments for cancer, neurodegenerative disorder and age‑related diseases.

A multifunctional mitochondria-protective gene delivery platform promote intervertebral disc regeneration

Intervertebral disc degeneration (IDD) is a deleterious condition driven by localized inflammation and the associated disruption of the normal homeostatic balance between anabolism and catabolism, contributing to progressive functional abnormalities within the nucleus pulposus (NP). Despite our prior evidence demonstrating that a miR-21 inhibitor can have regenerative effects that counteract the progression of IDD, its application for IDD treatment remains limited by the inadequacy of current local delivery systems. Here, an injectable tannic acid (TA)-loaded hydrogel gene delivery system was developed and used for the encapsulation of a multifunctional mitochondria-protecting gene nanocarrier (PHs). This engineered platform was designed for the sustained on-demand delivery of both miR-21 inhibitor and ss-31 (mitochondrial-targeted peptide) constructs to the NP. This prepared hydrogel could be implanted into the intervertebral disc using a minimally invasive approach whereupon it was able to rapidly release TA. Sustained PHs release was then achieved as appropriate through a mechanism mediated by the activity of MMP-2. Following the targeted uptake of PHs by degenerated NP cells, the subsequent release of encapsulated miR-21 inhibitor suppressed apoptotic cell death and modulated the metabolism of the extracellular matrix (ECM) by targeting the Spry1 gene. At the same time, ss-31 was able to target damaged mitochondria and alleviate inflammatory activity via the suppression of mitochondrial ROS-NLRP3-IL-1β/Caspase1 pathway activity. Synergistic ECM regeneration and anti-inflammatory effects were sufficient to provide therapeutic benefits in an in vivo model of IDD. Together, these results thus highlight this hydrogel-based gene delivery platform as a promising novel approach to the treatment of IDD.

The BCL2 family: from apoptosis mechanisms to new advances in targeted therapy

The B cell lymphoma 2 (BCL2) protein family critically controls apoptosis by regulating the release of cytochrome c from mitochondria. In this cutting-edge review, we summarize the basic biology regulating the BCL2 family including canonical and non-canonical functions, and highlight milestones from basic research to clinical applications in cancer and other pathophysiological conditions. We review laboratory and clinical development of BH3-mimetics as well as more recent approaches including proteolysis targeting chimeras (PROTACs), antibody-drug conjugates (ADCs) and tools targeting the BH4 domain of BCL2. The first BCL2-selective BH3-mimetic, venetoclax, showed remarkable efficacy with manageable toxicities and has transformed the treatment of several hematologic malignancies. Following its success, several chemically similar BCL2 inhibitors such as sonrotoclax and lisaftoclax are currently under clinical evaluation, alone and in combination. Genetic analysis highlights the importance of BCL-XL and MCL1 across different cancer types and the possible utility of BH3-mimetics targeting these proteins. However, the development of BH3-mimetics targeting BCL-XL or MCL1 has been more challenging, with on-target toxicities including thrombocytopenia for BCL-XL and cardiac toxicities for MCL1 inhibitors precluding clinical development. Tumor-specific BCL-XL or MCL1 inhibition may be achieved by novel targeting approaches using PROTACs or selective drug delivery strategies and would be transformational in many subtypes of malignancy. Taken together, we envision that the targeting of BCL2 proteins, while already a success story of translational research, may in the foreseeable future have broader clinical applicability and improve the treatment of multiple diseases.

Higher isoform of hnRNPA1 confer Temozolomide resistance in U87MG & LN229 glioma cells

BACKGROUND

Gliblastoma is a malignant brain tumor; despite available treatment modalities, the tumor reoccurrence rate persist in the currently prescribed Temozolomide chemotherapy. Study aimed to study the inquisitive role of RNA binding splice factor protein hnRNPA1 in promoting glioma resistance against Temozolomide drug and therapeutic insights.

METHODS

In this study two non-expressing O6-methylguanine-DNA methyltransferase (MGMT) glioma cell lines U87MG & LN229. U87MG cells were grown in Temozolomide from 50μM upto 400μM & LN229 cells grown upto 200μM, till then both these cells acquired Temozolomide resistance. Both of these cells were grown & maintained continously in its highest dose of Temozolomide (TMZ). Splice factor protein SF2/ASF1 was functionally correlated with abundance of hnRNPA1 protein in Temozolomide (TMZ) resistant cells using its specific siRNA transfection approach, in detrmining SF2/ASF1 mediated hnRNPA1 splicing and Temozolomide resistant reversal.

RESULTS

U87MG TMZ resistance, results an increase in the expression of pre mRNA-splicing factor SF2/ASF1, Heterogeneous Ribonucleoprotein A1 (hnRNPA1) and O6-methylguanine-DNA methyltransferase (MGMT) protein. MGMT expression was not observed in LN229 TMZ resistant cells. Further, mRNA sequencing of hnRNPA1 confirmed the exclusive abundance of its higher isoform in TMZ- resistant cells along with increase in SF2/ASF1 expression. Knocking down of SF2/ASF1 using its specific siRNA reverted the higher isoform of hnRNPA1 isoform Var2 to its lower isoform hnRNPA1 Var1 in U87 TMZ resistant cells, reveals hnRNPA1 alternative higher isoform abundance is SF2/ASF1 splice factor dependent. Additionally, selective knock down of hnRNPA1 higher isoform Var2 in TMZ resistant U87MG & LN229 promotes apoptosis, was further specfically enhanced on Wortmannin (PI3Kinase inhibitor) treatment.

CONCLUSION

Targeting higher isoform Var2 of hnRNPA1 specifically induces chemosensitization in MGMT expressed Temozolomide resistant U87MG as well as in MGMT non-expressed LN229 TMZ resistant cells.

Tipping the balance of cell death: alternative splicing as a source of MCL-1S in cancer

Apoptosis-regulating proteins from the B-cell lymphoma-2 (BCL-2) family are of continued interest as they represent promising targets for anti-cancer therapies. Myeloid cell leukemia-1 (MCL-1), which usually refers to the long isoform (MCL-1L) is frequently overexpressed in various types of cancer. However, MCL1 pre-mRNA can also undergo alternative splicing through exon skipping to yield the short isoform, MCL-1S. Regarding its structure and function, MCL-1S corresponds to BCL-2 homology domain 3 (BH3)-only pro-apoptotic proteins in contrast to the pro-survival role of MCL-1L. As cancer cells are usually characterized by the high MCL-1L:MCL-1S ratio, several studies revealed that overexpression of MCL-1S may constitute a new therapeutic approach in cancer and presumably overcome resistance to currently available drugs. Switching the balance towards high levels of MCL-1S is feasible by using inhibitors of alternative splicing-regulating proteins and strategies directly interfering with MCL1 pre-mRNA. Additionally, several compounds were shown to increase MCL-1S levels through unelucidated mechanisms, while diversely affecting the level of MCL-1L isoform. These mechanisms require detailed clarification as the balance between the long and short variants of MCL-1 can also contribute to mitochondrial hyperpolarization. In this respect, the role of MCL-1S in the regulation of apoptosis-unrelated events of the mitochondria physiology, including mitochondria fission and fusion also remains to be determined. In this review, the structure and function of MCL-1S isoform, and MCL-1S-targeting approaches are discussed.

The Role of miR-29a and miR-143 on the Anti-apoptotic MCL-1/cIAP-2 Genes Expression in EGFR Mutated Non-small Cell Lung Carcinoma Patients

The survival rate of lung cancer is low due to the high frequency of drug resistance in patients with mutations in the driver genes. Overexpression of anti-apoptotic genes is one of the most prominent features of tumor drug resistance. EGFR signaling induces the expression of anti-apoptotic genes. Also, microRNAs (miRNAs) have a critical role in regulating biological functions such as apoptosis; a process mostly eluded in cancer progression. The mutation screening was performed on one thousand non-small cell lung carcinoma patients to enroll clinical samples in this study. Bioinformatics analysis predicted that miRNAs (miR-29a, miR-143) might regulate MCL-1 and cIAP-2 expression. We investigated the expression of MCL-1, cIAP-2, miR-29a, and miR-143 encoding genes in adenocarcinoma patients with or without EGFR mutations before treatment. The potential role of miR-29a and miR-143 on gene expression was evaluated by overexpression and luciferase assays in HEK-293T cells. EGFR mutations were found in 262 patients (26.2%) with a greater incidence in females (36.23% vs. 20.37%, P = 0.001). The expression levels of MCL-1 and cIAP-2 genes in patients with mutated EGFR were higher than those of wild-type EGFR. In contrast, compared to those of patients with wild-type EGFR, the expression levels of miR-29a and miR-143 were lower in the patients carrying EGFR mutations. In cell culture, overexpression of miR-29a and miR-143 significantly downregulated the expression of MCL-1 and cIAP-2. Dual-luciferase reporter experiments confirmed that miR-29a and miR-143 target MCL-1 and cIAP-2 mRNAs, respectively. Our results suggest that upregulation of EGFR signaling in lung cancer cells may increase anti-apoptotic MCL-1 and cIAP-2 gene expression, possibly through downregulation of miR-29a-3p and miR-143-3p.

Metabolomic Profiling and Network Toxicology: Mechanistic Insights into Effect of Gossypol Acetate Isomers in Uterine Fibroids and Liver Injury

OBJECTIVE

Gossypol is a natural polyphenolic dialdehyde product that is primarily isolated from cottonseed. It is a racemized mixture of (-)-gossypol and (+)-gossypol that has anti-infection, antimalarial, antiviral, antifertility, antitumor and antioxidant activities, among others. Gossypol optical isomers have been reported to differ in their biological activities and toxic effects.

METHOD

In this study, we performed a metabolomics analysis of rat serum using 1H-NMR technology to investigate gossypol optical isomers' mechanism of action on uterine fibroids. Network toxicology was used to explore the mechanism of the liver injury caused by gossypol optical isomers. SD rats were randomly divided into a normal control group; model control group; a drug-positive group (compound gossypol acetate tablets); high-, medium- and low-dose (-)-gossypol acetate groups; and high-, medium- and low-dose (+)-gossypol acetate groups.

RESULT

Serum metabolomics showed that gossypol optical isomers' pharmacodynamic effect on rats' uterine fibroids affected their lactic acid, cholesterol, leucine, alanine, glutamate, glutamine, arginine, proline, glucose, etc. According to network toxicology, the targets of the liver injury caused by gossypol optical isomers included HSP90AA1, SRC, MAPK1, AKT1, EGFR, BCL2, CASP3, etc. KEGG enrichment showed that the toxicity mechanism may be related to pathways active in cancer, such as the PPAR signaling pathway, glycolysis/glycolysis gluconeogenesis, Th17 cell differentiation, and 91 other closely related signaling pathways.

CONCLUSIONS

(-)-gossypol acetate and (+)-gossypol acetate play positive roles in the treatment and prevention of uterine fibroids. Gossypol optical isomers cause liver damage through multiple targets and pathways.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Targeting z-Crystallin by aspirin restores the sensitivity to cisplatin in resistant A2780 ovarian cancer cells

Ovarian cancer is the deadliest gynaecologic malignancies worldwide. Platinum based chemotherapy is the mainstay treatment for ovarian cancer; however, frequent recurrence and chemoresistance onset in patients with advanced diseases remain a therapeutic challenge. Although mechanisms underlying the development of chemoresistance are still ambiguous, the B-cell lymphoma-2 (Bcl-2) family is closely associated with chemoresistance in ovarian cancer. We previously disclosed that Zeta-Crystallin (CryZ) is a post-transcriptional regulator of Bcl-2 gene expression, by binding to Bcl-2 mRNA and increasing its half-life. Here, we investigated the role of CryZ as a novel therapeutic target in A2780 ovarian carcinoma cells by modulating the protein activity with acetylsalicylic acid (ASA) to restore chemosensitivity. Molecular docking and fragment-mapping based approach revealed potential interaction of ASA within CryZ protein. Inhibition of CryZ binding activity to Bcl-2 and Bcl-xl mRNA targets by ASA was demonstrated in A375 cells. Cytotoxicity assays were conducted in A2780S and A2780R ovarian cancer cells to evaluate if CryZ binding activity inhibition and CryZ silencing were able to reverse cisplatin resistance. ASA-treatment determined a downregulation of Bcl-2 and Bcl-xl mRNA levels in A2780S and A2780R cells. ASA-treatment or CryZ silencing were able to increase and restore the chemosensitivity in both sensitive and resistant A2780 ovarian cancer cells, respectively. In this research article we demonstrated that the pharmacological or genetic inhibition of CryZ restores the sensitivity to cisplatin in a model of sensitive or resistant ovarian cancer cells. These findings suggest a new gene-targeted chemotherapeutic approach to restore the cytotoxicity in drug-resistant ovarian cancers and increase the sensitivity in non-resistant cells.

Unlocking the Therapeutic Potential of BCL-2 Associated Protein Family: Exploring BCL-2 Inhibitors in Cancer Therapy

Apoptosis, programmed cell death pathway, is a vital physiological mechanism that ensures cellular homeostasis and overall cellular well-being. In the context of cancer, where evasion of apoptosis is a hallmark, the overexpression of anti-apoptotic proteins like Bcl2, Bcl-xL and Mcl-1 has been documented. Consequently, these proteins have emerged as promising targets for therapeutic interventions. The BCL-2 protein family is central to apoptosis and plays a significant importance in determining cellular fate serving as a critical determinant in this biological process. This review offers a comprehensive exploration of the BCL-2 protein family, emphasizing its dual nature. Specifically, certain members of this family promote cell survival (known as anti-apoptotic proteins), while others are involved in facilitating cell death (referred to as pro-apoptotic and BH3-only proteins). The potential of directly targeting these proteins is examined, particularly due to their involvement in conferring resistance to traditional cancer therapies. The effectiveness of such targeting strategies is also discussed, considering the tumor's propensity for anti-apoptotic pathways. Furthermore, the review highlights emerging research on combination therapies, where BCL-2 inhibitors are used synergistically with other treatments to enhance therapeutic outcomes. By understanding and manipulating the BCL-2 family and its associated pathways, we open doors to innovative and more effective cancer treatments, offering hope for resistant and aggressive cases.

Roles and mechanisms of aberrant alternative splicing in melanoma - implications for targeted therapy and immunotherapy resistance

BACKGROUND

Despite advances in therapeutic strategies, resistance to immunotherapy and the off-target effects of targeted therapy have significantly weakened the benefits for patients with melanoma.

MAIN BODY

Alternative splicing plays a crucial role in transcriptional reprogramming during melanoma development. In particular, aberrant alternative splicing is involved in the efficacy of immunotherapy, targeted therapy, and melanoma metastasis. Abnormal expression of splicing factors and variants may serve as biomarkers or therapeutic targets for the diagnosis and prognosis of melanoma. Therefore, comprehensively integrating their roles and related mechanisms is essential. This review provides the first detailed summary of the splicing process in melanoma and the changes occurring in this pathway.

CONCLUSION

The focus of this review is to provide strategies for developing novel diagnostic biomarkers and summarize their potential to alter resistance to targeted therapies and immunotherapy.

m6A-related lncRNAs as potential biomarkers and the lncRNA ELFN1-AS1/miR-182-5p/BCL-2 regulatory axis in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoid subtype. However, unsatisfactory survival outcomes remain a major challenge, and the underlying mechanisms are poorly understood. N6-methyladenosine (m6A), the most common internal modification of eukaryotic mRNA, participates in cancer pathogenesis. In this study, m6A-associated long non-coding RNAs (lncRNA) were retrieved from publicly available databases. Univariate, LASSO, and multivariate Cox regression analyses were performed to establish an m6A-associated lncRNA model specific to DLBCL. Kaplan-Meier curves, principal component analysis, functional enrichment analyses and nomographs were used to study the risk model. The underlying clinicopathological characteristics and drug sensitivity predictions against the model were identified. Risk modelling based on the three m6A-associated lncRNAs was an independent prognostic factor. By regrouping patients using our model-based method, we could differentiate patients more accurately for their response to immunotherapy. In addition, prospective compounds that can target DLBCL subtypes have been identified. The m6A-associated lncRNA risk-scoring model developed herein holds implications for DLBCL prognosis and clinical response prediction to immunotherapy. In addition, we used bioinformatic tools to identify and verify the ceRNA of the m6A-associated lncRNA ELFN1-AS1/miR-182-5p/BCL-2 regulatory axis. ELFN1-AS1 was highly expressed in DLBCL and DLBCL cell lines. ELFN1-AS1 inhibition significantly reduced the proliferation of DLBCL cells and promoted apoptosis. ABT-263 inhibits proliferation and promotes apoptosis in DLBCL cells. In vitro and in vivo studies have shown that ABT-263 combined with si-ELFN1-AS1 can inhibit DLBCL progression.

Dexmedetomidine against intestinal ischemia/reperfusion injury: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Intestinal ischemia/reperfusion injury (IRI) is a multifactorial, complex pathophysiological process in clinical settings. In recent years, intestinal IRI has received increasing attention due to increased morbidity and mortality. To date, there are no effective treatments. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, has been demonstrated to be effective against intestinal IRI. In this systematic review and meta-analysis, we evaluated the efficacy and potential mechanisms of DEX as a treatment for intestinal IRI in animal models.

METHODS

Five databases (PubMed, Embase, Web of Science, Cochrane Library, and Scopus) were searched until March 15, 2023. Using the SYRCLE risk bias tool, we assessed methodological quality. Statistical analysis was conducted using STATA 12 and R 4.2.2. We analyzed the related outcomes (mucosa damage-related indicators; inflammation-relevant markers, oxidative stress markers) relied on the fixed or random-effects models.

RESULTS

There were 15 articles including 18 studies included, and 309 animals were involved in the studies. Compared to the model groups, DEX improved intestinal IRI. DEX decreased Chiu's score and serum diamine oxidase (DAO) level. DEX reduced the level of inflammation-relevant markers (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α). DEX also improved oxidative stress (decreased malondialdehyde (MDA), increased superoxide dismutase (SOD)).

CONCLUSIONS

DEX's effectiveness in ameliorating intestinal IRI has been demonstrated in animal models. Antioxidation, anti-inflammation, anti-apoptotic, anti-pyroptosis, anti-ferroptosis, enhancing mitophagy, reshaping the gut microbiota, and gut barrier protection are possible mechanisms. However, in light of the heterogeneity and methodological quality of these studies, further well-designed preclinical studies are warranted before clinical implication.

Study of anticancer effects of platinum levetiracetam and levetiracetam via cancer biomarkers genes expression on HepG2 cell line

BACKGROUND

High expression of some anticancer biomarkers such as telomerase and B cell lymphoma-2(Bcl-2), microRNA-21(miRNA-21), and low expression FAS ligand (FASLG) are reported in many cancers. Some anticancer drugs such as Levetiracetam(Lev) produce their effects via the change of expression of these biomarkers. The present study aimed to evaluate the anti-cancer effects of a new compound, Platinum Levetiracetam(Pt-Lev), gene expression of mentioned biomarkers on hepatocyte G2 (HepG2) cells compared to Lev.

METHODS AND RESULTS

In this study, Human Dermal fibroblast cells (HDF) were used as the negative control group (group A) HepG2 cells were divided into three groups: untreated cancer cells as positive group (group B), groups C and D were treated with, Lev and Pt-Lev, respectively. After evaluating lethal concentration 50% (LC50) for the examined drugs using the MTT test, biomarker gene expression was evaluated by real-time PCR. No Apoptotic cell was found in groups C or D before drug treatment, but it was present using different concentrations of the drugs. Results indicated that telomerase and miRNA-21 genes expression was significantly lower and FASLG was higher in group D compared with group C but there was no significant difference for Bcl-2 expression between these two groups.

CONCLUSIONS

For the first time, it was indicated that Pt-Lev has anticancer effects by inhibiting telomerase and Bcl-2 and miRNA-21 and increasing FASLG gene expression and its effects were more than Lev. It effectively exerted its anticancer effects by extending apoptosis on HepG2 cells.

Fine tuning of the transcription juggernaut: A sweet and sour saga of acetylation and ubiquitination

Among post-translational modifications of proteins, acetylation, phosphorylation, and ubiquitination are most extensively studied over the last several decades. Owing to their different target residues for modifications, cross-talk between phosphorylation with that of acetylation and ubiquitination is relatively less pronounced. However, since canonical acetylation and ubiquitination happen only on the lysine residues, an overlap of the same lysine residue being targeted for both acetylation and ubiquitination happens quite frequently and thus plays key roles in overall functional regulation predominantly through modulation of protein stability. In this review, we discuss the cross-talk of acetylation and ubiquitination in the regulation of protein stability for the functional regulation of cellular processes with an emphasis on transcriptional regulation. Further, we emphasize our understanding of the functional regulation of Super Elongation Complex (SEC)-mediated transcription, through regulation of stabilization by acetylation, deacetylation and ubiquitination and associated enzymes and its implication in human diseases.

The RNA binding proteins TIA1 and TIAL1 promote Mcl1 mRNA translation to protect germinal center responses from apoptosis

Germinal centers (GCs) are essential for the establishment of long-lasting antibody responses. GC B cells rely on post-transcriptional RNA mechanisms to translate activation-associated transcriptional programs into functional changes in the cell proteome. However, the critical proteins driving these key mechanisms are still unknown. Here, we show that the RNA binding proteins TIA1 and TIAL1 are required for the generation of long-lasting GC responses. TIA1- and TIAL1-deficient GC B cells fail to undergo antigen-mediated positive selection, expansion and differentiation into B-cell clones producing high-affinity antibodies. Mechanistically, TIA1 and TIAL1 control the transcriptional identity of dark- and light-zone GC B cells and enable timely expression of the prosurvival molecule MCL1. Thus, we demonstrate here that TIA1 and TIAL1 are key players in the post-transcriptional program that selects high-affinity antigen-specific GC B cells.

Role of YY1 in the Regulation of Anti-Apoptotic Gene Products in Drug-Resistant Cancer Cells

Cancer is a leading cause of death among the various diseases encountered in humans. Cancer is not a single entity and consists of numerous different types and subtypes that require various treatment regimens. In the last decade, several milestones in cancer treatments were accomplished, such as specific targeting agents or revitalizing the dormant anti-tumor immune response. These milestones have resulted in significant positive clinical responses as well as tumor regression and the prolongation of survival in subsets of cancer patients. Hence, in non-responding patients and non-responding relapsed patients, cancers develop intrinsic mechanisms of resistance to cell death via the overexpression of anti-apoptotic gene products. In parallel, the majority of resistant cancers have been reported to overexpress a transcription factor, Yin Yang 1 (YY1), which regulates the chemo-immuno-resistance of cancer cells to therapeutic anticancer cytotoxic agents. The relationship between the overexpression of YY1 and several anti-apoptotic gene products, such as B-cell lymphoma 2 protein (Bcl-2), B-cell lymphoma extra-large (Bcl-xL), myeloid cell leukemia 1 (Mcl-1) and survivin, is investigated in this paper. The findings demonstrate that these anti-apoptotic gene products are regulated, in part, by YY1 at the transcriptional, epigenetic, post-transcriptional and translational levels. While targeting each of the anti-apoptotic gene products individually has been examined and clinically tested for some, this targeting strategy is not effective due to compensation by other overexpressed anti-apoptotic gene products. In contrast, targeting YY1 directly, through small interfering RNAs (siRNAs), gene editing or small molecule inhibitors, can be therapeutically more effective and generalized in YY1-overexpressed resistant cancers.

The anti-cancer effect and mechanism of animal scale-derived extract on malignant melanoma cells

Melanoma is a type of cancer with abnormal proliferation of melanocytes and is one of the most diagnosed cancer types. In traditional Chinese medicine, pangolin scales have been used to treat various diseases, including human cancers. However, its efficacy has not been scientifically proven. Here we studied the anticancer effect and mechanism of pangolin scale extract (PSE) on melanoma cell lines using scientific approaches. Our cell viability assay shows that PSE exhibits up to approximately 50-80% inhibition on SK-MEL-103 and A375 melanoma cell lines. Mechanically, PSE inhibits melanoma cell proliferation, migration, and causes changes in cell morphology. The apoptosis assay showed a significant chromosomal condensation inside the PSE-treated melanoma cells. The sequencing and analysis of A375 melanoma cell transcriptomes revealed 3077 differentially expressed genes in the 6 h treatment group and 8027 differentially expressed genes in the 72 h treatment group. Transcriptome analysis suggests that PSE may cause cell cycle arrest in melanoma cells and promote apoptosis mainly by up-regulating the p53 signaling pathway and down-regulating the PI3K-Akt signaling pathway. In this study, the anticancer effect of PSE was demonstrated by molecular biological means. PSE shows a significant inhibition effect on melanoma cell proliferation and cell migration in vitro, causes cell cycle arrest and promotes apoptosis through p53 and PI3K-AKT pathways. This study provides better insights into the anti-cancer efficacy and underlying mechanism of PSE and a theoretical basis for mining anticancer compounds or the development of new treatments for melanoma in the future. It is worth noting that this study does not advocate the use of the pangolin scale for disease treatment, but only to confirm its usefulness from a scientific research perspective and to encourage subsequent research around the development of active compounds to replace pangolin scales to achieve the conservation of this endangered species.

METTL3 Affects Spinal Cord Neuronal Apoptosis by Regulating Bcl-2 m6A Modifications After Spinal Cord Injury

OBJECTIVE

Spinal cord injury (SCI) is a severe type of neurological trauma. N6-methyladenosine (m6A) modification is one of the most common internal modifications of RNA. The role of METTL3, the predominant methylation enzyme of m6A modification, in SCI remains unclear. This study aimed to investigate the role of methyltransferase METTL3 in SCI.

METHODS

After establishing the oxygen-glucose deprivation (OGD) model of PC12 cells and rat spinal cord hemisection model, we found that the expression of METTL3 and the overall m6A modification level were significantly increased in neurons. The m6A modification was identified on B-cell lymphoma 2 (Bcl-2) messenger RNA (mRNA) by bioinformatics analysis, and m6A-RNA immunoprecipitation and RNA immunoprecipitation. In addition, METTL3 was blocked by the specific inhibitor STM2457 and gene knockdown, and then apoptosis levels were measured.

RESULTS

In different models, we found that the expression of METTL3 and the overall m6A modification level were significantly increased in neurons. After inducing OGD, inhibition of METTL3 activity or expression increased the mRNA and protein levels of Bcl-2, inhibited neuronal apoptosis, and improved neuronal viability in the spinal cord.

CONCLUSION

Inhibition of METTL3 activity or expression can inhibit the apoptosis of spinal cord neurons after SCI through the m6A/Bcl-2 signaling pathway.

Identification, expression profiling, and functional characterization of cystatin C from big-belly seahorse (Hippocampus abdominalis)

Cystatins are natural inhibitors of lysosomal cysteine proteases, including cathepsins B, L, H, and S. Cystatin C (CSTC) is a member of the type 2 cystatin family and is an essential biomarker in the prognosis of several diseases. Emerging evidence suggests the immune regulatory roles of CSTC in antigen presentation, the release of different inflammatory mediators, and apoptosis in various pathophysiologies. In this study, the 390-bp cystatin C (HaCSTC) cDNA from big-belly seahorse (Hippocampus abdominalis) was cloned and characterized by screening the pre-established cDNA library. Based on similarities in sequence, HaCSTC is a homolog of the teleost type 2 cystatin family with putative catalytic cystatin domains, signal peptides, and disulfide bonds. HaCSTC transcripts were ubiquitously expressed in all tested big-belly seahorse tissues, with the highest expression in ovaries. Immune challenge with lipopolysaccharides, polyinosinic:polycytidylic acid, Edwardsiella tarda, and Streptococcus iniae caused significant upregulation in HaCSTC transcript levels. Using a pMAL-c5X expression vector, the 14.29-kDa protein of recombinant HaCSTC (rHaCSTC) was expressed in Escherichia coli BL21 (DE3), and its protease inhibitory activity against papain cysteine protease was determined with the aid of a protease substrate. Papain was competitively blocked by rHaCSTC in a dose-dependent manner. In response to viral hemorrhagic septicemia virus (VHSV) infection, HaCSTC overexpression strongly decreased the expression of VHSV transcripts, pro-inflammatory cytokines, and pro-apoptotic genes; while increasing the expression of anti-apoptotic genes in fathead minnow (FHM) cells. Furthermore, HaCSTC overexpression protected VHSV-infected FHM cells against VHSV-induced apoptosis and increased cell viability. Our findings imply the profound role of HaCSTC against pathogen infections by modulating fish immune responses.

Silymarin in combination with ATRA enhances apoptosis induction in human acute promyelocytic NB4 cells

Although all-trans retinoic acid (ATRA) is an efficient pattern in acute promyelocytic leukemia (APL) therapy, further studies are required due to the extant clinical limitations of ATRA. It has been reported that Silymarin, an anti-cancer herbal substance extracted from milk thistle (Silybum marianum), is able to regulate apoptosis in various types of cancer cells through different mechanisms of action. This study investigated the apoptosis-inducing effect of Silymarin (SM) alone and in combination with ATRA on human acute promyelocytic NB4 cells. Examination using MTT assay indicated that SM treatment leads to growth inhibition in NB4 cells in a dose-dependent manner. The IC50 values of SM and ATRA were calculated 90 μM and 2 μM, respectively. Cell cycle analysis by flow cytometry revealed that a more increase in the sub-G1 phase (a sign of apoptosis) when cells were exposed to SM in combination with ATRA. The incidence of apoptosis was confirmed through Hoechst 33258 staining and Annexin V-FITC analysis. The results showed that Silymarin enhances ATRA-induced apoptosis. The flow cytometric analysis also indicated an enhancement in levels of ROS in the treated cells with both compounds. The real-time PCR illustrated that SM targets apoptosis by down-regulation in Survivin and Bcl-2 while up-regulation in Bax. The findings showed that the combination of the two compounds is more effective in the induction of apoptosis in NB4 cells. Molecular docking studies indicated that Sylibin, as a primary compound of the SM, binds to the BH3 domain of Bcl-2 and the BIR domain of Survivin with various affinities. Based on the findings, it seems that SM used alone and in combination with ATRA may be beneficial for inducing apoptosis in APL cells.

How does precursor RNA structure influence RNA processing and gene expression?

RNA is a fundamental biomolecule that has many purposes within cells. Due to its single-stranded and flexible nature, RNA naturally folds into complex and dynamic structures. Recent technological and computational advances have produced an explosion of RNA structural data. Many RNA structures have regulatory and functional properties. Studying the structure of nascent RNAs is particularly challenging due to their low abundance and long length, but their structures are important because they can influence RNA processing. Precursor RNA processing is a nexus of pathways that determines mature isoform composition and that controls gene expression. In this review, we examine what is known about human nascent RNA structure and the influence of RNA structure on processing of precursor RNAs. These known structures provide examples of how other nascent RNAs may be structured and show how novel RNA structures may influence RNA processing including splicing and polyadenylation. RNA structures can be targeted therapeutically to treat disease.

Delivery of miR-130a-3p Through Adipose-Derived Stem Cell-Secreted EVs Protects Against Diabetic Peripheral Neuropathy via DNMT1/NRF2/HIF1α/ACTA1 Axis

Peripheral neuropathy is common in diabetic patients and can lead to amputations or foot ulcers. microRNAs (miRNAs) possess crucial roles in diabetic peripheral neuropathy (DPN). This study aims to investigate the role miR-130a-3p played in DPN and its underlying molecular mechanisms. miR-130a-3p expression in clinical tissue samples, established DPN rat models, and extracellular vesicles (EVs) derived from adipose-derived stem cells (ADSCs) were determined. Schwann cells (SCs) were co-cultured with ADSC-derived EVs and treated with high glucose. The direct relationship and functional significance of miR-130a-3p, DNMT1, nuclear factor E2-related factor 2 (NRF2), hypoxia-inducible factor-1α (HIF1α), and skeletal muscle actin alpha 1 (ACTA1) was identified. The in vitro and in vivo implication of ADSC-derived EVs carrying miR-130a-3p was assessed. miR-130a-3p was poorly expressed in DPN patients and rats but highly expressed in ADSC-derived EVs. miR-130a-3p could be delivered to SCs through ADSC-derived EVs to inhibit SC apoptosis and promote proliferation under a high-glucose environment. miR-130a-3p activated NRF2/HIF1α/ACTA1 axis through down-regulating DNMT1. In vivo injection of ADSC-derived EVs activated NRF2/HIF1α/ACTA11 axis to promote angiogenesis in DPN rat model. These data together supported that ADSC-derived EVs carrying miR-130a-3p could alleviate DPN by accelerating SC proliferation and inhibiting apoptosis, providing a potential treatment against DPN.

Leucocyte Abnormalities in Synovial Fluid of Degenerative and Inflammatory Arthropathies

Genome damage has been related to the induction of autoimmune processes, chronic inflammation, and apoptosis. Recent studies suggest that some rheumatological diseases are associated with overall genomic instability in the T cell compartment. However, no data regarding leucocyte abnormalities in synovial fluid (SF) and their relationship with inflammation are available. The aim of this study was to investigate cellular phenotypes in SF collected from patients with different inflammatory arthropathies, including rhematoid arthritis (RA), psoriatic arthritis (PsA), crystal-induced arthritis (CIA), and non-inflammatory arthropathies, such as osteoarthritis (OA). We found high percentage of micronuclei in SF from CIA compared to the other groups and a high frequency of pyknotic cell in RA and CIA patients. A correlation between pyknosis and immature polymorphonuclear cells with local inflammatory indices was observed. The study of the apoptosis process revealed an increased BAX expression in CIA and RA compared to OA and PsA, while Bcl-2 was higher in CIA. Caspase-3 activity was increased in SF from RA patients and correlates with inflammatory and anti-inflammatory cytokines. In conclusion, our results showed that inflammatory SF is associated with genomic instability and abnormal cell subsets.

miR-450-5p and miR-202-5p Synergistically Regulate Follicle Development in Black Goat

Follicle maturation is a complex biological process governed by numerous factors, and researchers have observed follicle development by studying the proliferation and apoptosis of follicular granulosa cells (GCs). However, the regulatory mechanisms of GCs proliferation and death during follicle development are largely unknown. To investigate the regulatory mechanisms of lncRNAs, mRNAs, and microRNAs, RNA sequencing (RNA-seq) and small RNA-seq were performed on large (>10 mm) and small follicles (<3 mm) of Leizhou black goat during estrus. We discovered two microRNAs, miR-450-5p and miR-202-5p, which can target GCs in goats and may be involved in follicle maturation, and the effects of miR-450-5p and miR-202-5p on ovarian granulosa cell lines were investigated (KGN). Using cell counting kit-8 (CCK-8) assays, 5-Ethynyl-2’-deoxyuridine (EdU) assay and flow cytometry, miR-202-5p overexpression could suppress the proliferation and induce apoptosis of GCs, whereas miR-450-5p overexpression induced the opposite effects. The dual-luciferase reporter assay confirmed that miR-450-5p could directly target the BMF gene (a BCL2 modifying factor), and miR-202-5p targeted the BCL2 gene. A considerable rise in phosphorylated Akt (p-AKT) protein was observed following the downregulation of BMF by miR-450-5p mimics. After BMF gene RNAi therapy, a notable elevation in p-AKT was detected. Mimics of miR-202-5p inhibited BCL2 protein expression, significantly decreasing p-AMPK protein expression. These results imply that during the follicular development in black goats, the miR-450-5p-BMF axis favored GC proliferation on a wide scale, while the miR-202-5p-BCL2 axis triggered GC apoptosis.

RNA-binding proteins: Underestimated contributors in tumorigenesis

mRNA export, translation, splicing, cleavage or capping determine mRNA stability, which represents one of the primary aspects regulating gene expression and function. RNA-binding proteins (RBPs) bind to their target mRNAs to regulate multiple cell functions by increasing or reducing their stability. In recent decades, studies of the role of RBPs in tumorigenesis have revealed an increasing number of proteins impacting the prognosis, diagnosis and cancer treatment. Several RBPs have been identified based on their interactions with oncogenes or tumor suppressor genes in human cancers, which are involved in apoptosis, the epithelial-mesenchymal transition (EMT), DNA repair, autophagy, cell proliferation, immune response, metabolism, and the regulation of noncoding RNAs. In this review, we propose a model showing how RBP mutations influence tumorigenesis, and we update the current knowledge regarding the molecular mechanism by which RBPs regulate cancer. Special attention is being devoted to RBPs that represent prognostic and diagnostic factors in cancer patients.

Understanding MCL1: from cellular function and regulation to pharmacological inhibition

Myeloid cell leukemia-1 (MCL1), an antiapoptotic member of the BCL2 family characterized by a short half-life, functions as a rapid sensor that regulates cell death and other relevant processes that include cell cycle progression and mitochondrial homeostasis. In cancer, MCL1 overexpression contributes to cell survival and resistance to diverse chemotherapeutic agents; for this reason, several MCL1 inhibitors are currently under preclinical and clinical development for cancer treatment. However, the nonapoptotic functions of MCL1 may influence their therapeutic potential. Overall, the complexity of MCL1 regulation and function represent challenges to the clinical application of MCL1 inhibitors. We now summarize the current knowledge regarding MCL1 structure, regulation, and function that could impact the clinical success of MCL1 inhibitors.

Roles of C/EBP-homologous protein and histone H3 lysine 4 methylation in arsenic-induced mitochondrial apoptosis in hepatocytes

C/EBP-homologous protein (CHOP) and histone H3 lysine 4 (H3K4) methylation have been verified to be correlated with apoptosis, whereas their biological function in arsenic-induced hepatocyte apoptosis through the mitochondrial pathway is still unclear. This study aimed to explore the specific regulatory mechanism of CHOP and H3K4me1/2 in arsenic-induced mitochondrial apoptosis in hepatocytes. Apoptosis and proliferation results showed arsenic promoted apoptosis and inhibited cell growth in BRL-3A cells. Meanwhile, arsenic treatment significantly upregulated the 78-kDa glucose-regulated protein (GRP78), CHOP, su(var)-3-9,enhancer-of-zeste,trithorax (SET) domain containing 7/9 (SET7/9), H3K4me1/2, BIM and BAX expression, while markedly downregulated lysine-specific histone demethylase 1 (LSD1) and BCL2 expression. After down-regulating CHOP, LSD1, and (su(var)-3-9,enhancer-of-zeste,trithorax) domain-containing protein 7/9 (SET7/9) in BRL-3A cells by siRNA, silencing CHOP and SET7/9 notably attenuated the pro-apoptotic and anti-proliferative effects of arsenic treatment on BRL-3A cells, which was reversed after inhibiting LSD1. In addition, our results suggested that knockdown of CHOP altered the expression of mitochondrial-associated proteins BCL2 and BIM, whereas knockdown of LSD1 and SET7/8 regulated the level of H3K4me1/2 modification and BAX protein. Coupled with chromatin immunoprecipitation results, we found that the level of CHOP in the promoter regions of BCL2 and BIM was significantly increased in BRL-3A cells exposed to 30 µmol/L NaAsO2 for 24 h, whereas the levels of H3K4me1/2 in the promoter regions of BAX were unchanged. Collectively, these data indicated that arsenic triggered the mitochondrial pathway to induce hepatocyte apoptosis by up-regulating the levels of CHOP and H3K4me1/2.

An integrative systems biology approach to overcome venetoclax resistance in acute myeloid leukemia

The over-expression of the Bcl-2 protein is a common feature of many solid cancers and hematological malignancies, and it is typically associated with poor prognosis and resistance to chemotherapy. Bcl-2-specific inhibitors, such as venetoclax, have recently been approved for the treatment of chronic lymphocytic leukemia and small lymphocytic lymphoma, and they are showing promise in clinical trials as a targeted therapy for patients with relapsed or refractory acute myeloid leukemia (AML). However, successful treatment of AML with Bcl-2-specific inhibitors is often followed by the rapid development of drug resistance. An emerging paradigm for overcoming drug resistance in cancer treatment is through the targeting of mitochondrial energetics and metabolism. In AML in particular, it was recently observed that inhibition of mitochondrial translation via administration of the antibiotic tedizolid significantly affects mitochondrial bioenergetics, activating the integrated stress response (ISR) and subsequently sensitizing drug-resistant AML cells to venetoclax. Here we develop an integrative systems biology approach to acquire a deeper understanding of the molecular mechanisms behind this process, and in particular, of the specific role of the ISR in the commitment of cells to apoptosis. Our multi-scale mathematical model couples the ISR to the intrinsic apoptosis pathway in venetoclax-resistant AML cells, includes the metabolic effects of treatment, and integrates RNA, protein level, and cellular viability data. Using the mathematical model, we identify the dominant mechanisms by which ISR activation helps to overcome venetoclax resistance, and we study the temporal sequencing of combination treatment to determine the most efficient and robust combination treatment protocol.

In this work, we develop a multi-scale systems biology approach to study the mechanisms by which the integrated stress response (ISR) activation helps to overcome venetoclax resistance in acute myeloid leukemia (AML). The multi-scale model enables the integration of RNA-level, protein-level, and cellular viability and proliferation data. The model developed in this work can predict several important features of the resistant AML cell lines that are consistent with experimental data. Further, our integrative systems biology approach led to the determination of the optimal combination treatment protocol.

Post-Transcriptional Modifications of RNA as Regulators of Apoptosis in Glioblastoma

This review is devoted to changes in the post-transcriptional maturation of RNA in human glioblastoma cells, which leads to disruption of the normal course of apoptosis in them. The review thoroughly highlights the latest information on both post-transcriptional modifications of certain regulatory RNAs, associated with the process of apoptosis, presents data on the features of apoptosis in glioblastoma cells, and shows the relationship between regulatory RNAs and the apoptosis in tumor cells. In conclusion, potential target candidates are presented that are necessary for the development of new drugs for the treatment of glioblastoma.

Ameliorative effects of Dictyota dichotoma on hepatotoxicity induced by gibberellic acid in albino rats

Gibberellic acid (GA3) is a natural plant growth regulator that is crucial for plant structural and functional development. We examined the alleviating capacity of brown algae (Dictyota dichotoma) on biochemical and molecular degenerative processes caused by sub-chronic exposure to gibberellic acid resulting in hepatic cell apoptosis. Adult male albino rats were divided into five equal groups: the first group received distilled water, the second group was treated with GA3, the third group was administered D. dichotoma extract suspended in 1% carboxymethylcellulose (CMC), the fourth group was administered both GA3 and D. dichotoma simultaneously, and the fifth group received 1% CMC orally, 5 days per week for a total of 50 days. The results indicated that GA3 induced a significant increase in liver function parameters based on serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and albumin, which indicate hepatotoxicity. A marked increase in malondialdehyde (MDA) levels and a marked decrease in reduced glutathione (GSH), glutathione-S-transferase (GST), and superoxide dismutase (SOD) were observed as a result of induction of lipid peroxidation and oxidative stress. Histopathology revealed severely degenerated hepatocytes including cytoplasmic vacuolations and many apoptotic cells with weak Bcl2 expression. Similarly, there was a significant up-regulation of gene and protein expression levels for the pro-apoptotic markers, Caspase-3 and Bax, and an increase in pro-inflammatory marker levels, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) as well as C-reactive protein (CRP). The co-administration of D. dichotoma restored the disrupted biochemical, histopathological, molecular, and inflammatory changes resulting from GA3 toxicity. Our results confirm the antioxidant, anti-inflammatory, anti-apoptotic, and hepatoprotective potential of D. dichotoma.

The Role of microRNAs in Multidrug Resistance of Glioblastoma

Glioblastoma (GBM) is an aggressive brain tumor that develops from neuroglial stem cells and represents a highly heterogeneous group of neoplasms. These tumors are predominantly correlated with a dismal prognosis and poor quality of life. In spite of major advances in developing novel and effective therapeutic strategies for patients with glioblastoma, multidrug resistance (MDR) is considered to be the major reason for treatment failure. Several mechanisms contribute to MDR in GBM, including upregulation of MDR transporters, alterations in the metabolism of drugs, dysregulation of apoptosis, defects in DNA repair, cancer stem cells, and epithelial-mesenchymal transition. MicroRNAs (miRNAs) are a large class of endogenous RNAs that participate in various cell events, including the mechanisms causing MDR in glioblastoma. In this review, we discuss the role of miRNAs in the regulation of the underlying mechanisms in MDR glioblastoma which will open up new avenues of inquiry for the treatment of glioblastoma.

Oridonin attenuates hind limb ischemia-reperfusion injury by modulating Nrf2-mediated oxidative stress and NLRP3-mediated inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Oridonin (Ori), extracted from Isodon rubescens (Hemsl.) H.Hara, is a well-known traditional Chinese herbal medicinal product that possesses antioxidant and anti-inflammatory activities. Oxidative stress and inflammation are the main pathophysiological mechanisms in hindlimb IR injury. However, whether Ori has a protective effect on hind limb IR injury is unknown.

AIM OF THE STUDY

The present study was designed to determine the effect of Ori on hindlimb IR injury and its relationship with oxidative stress and inflammation.

MATERIALS AND METHODS

The hind limb IR injury model in mice was used to evaluate the protective effect and related mechanisms of Ori. Forty-eight C57BL/6 mice (n = 12 per group) were randomly divided into four groups: Sham group; IR group; IR + Ori (10 mg/kg) group and IR + Ori (20 mg/kg) group. Mice in the IR and IR + Ori groups were subjected to hindlimb IR injury, while mice in the Sham group were subjected to no hindlimb IR injury. HE staining, Masson's staining, TTC staining, DHE staining, TUNEL staining, western blotting analysis and quantitative real-time PCR were employed to explore the mechanisms by which Ori exerts a protective effect on a classical hindlimb IR model in mice.

RESULTS

We found that Ori pretreatment prevented muscle damage and decreased cell apoptosis levels compared with the vehicle control. Moreover, the SOD2, CAT, MDA and ROS levels in muscle showed that Ori could significantly reduce oxidative stress in hindlimb IR mice, while the IL-1β and TNF-α levels in muscle showed that Ori could significantly attenuate IR-induced inflammation. We also found that Ori could increase the expression of Nrf2 and its downstream protein HO-1 and inhibit the expression levels of NLRP3-related proteins (NLRP3, ASC and Caspase-1) in vivo.

CONCLUSIONS

Our study suggested that Ori has a protective effect on hindlimb IR injury, which may be related to Nrf2-mediated oxidative stress and NLRP3-mediated inflammasome activation.

[Regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts]

Objective: To investigate the regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts (HSFbs). Methods: The experimental research methods were used. The 4th-6th passage of HSFbs from human skin were used for the following experiments. HSFbs were co-cultured with sodium ferulate at final mass concentrations of 1, 1×10-1, 1×10-2, 1×10-3, 1×10-4, 1×10-5, and 1×10-6 mg/mL for 48 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and linear regression was used to analyze the half lethal concentration (LC50) of sodium ferulate (n=6). HSFbs were co-cultured with sodium ferulate at final mass concentrations of 0.1, 0.2, 0.3, and 0.4 mg/mL for 24, 48, 72, and 96 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and the cell proliferation inhibition rate was calculated (n=3). According to the random number table, the cells were divided into 0.300 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, 0.003 mg/mL sodium ferulate group treated with sodium ferulate at corresponding final mass concentrations, and negative control group without any treatment. After 72 hours of culture, the cell absorbance values were determined by methyl thiazolyl tetrazolium method (n=5), the microscopic morphology of cells was observed by transmission electron microscope (n=3), the cell apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay and the apoptosis index was calculated (n=4), the protein expressions of B lymphocystoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and cysteine aspartic acid specific protease-3 (caspase-3) were determined by immunohistochemistry (n=4), and the protein expressions of transformed growth factor β1 (TGF-β1), phosphorylated Smad2/3, phosphorylated Smad4, and phosphorylated Smad7 were detected by Western blotting (n=4). Data were statistically analyzed with one-way analysis of variance and Dunnett test. Results: The LC50 of sodium ferulate was 0.307 5 mg/mL. After being cultured for 24-96 hours, the cell proliferation inhibition rates of cells treated with sodium ferulate at four different mass concentrations tended to increase at first but decrease later, which reached the highest after 72 hours of culture, so 72 hours was chosen as the processing time for the subsequent experiments. After 72 hours of culture, the cell absorbance values in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were 0.57±0.06, 0.53±0.04, 0.45±0.05, respectively, which were significantly lower than 0.69±0.06 in negative control group (P<0.01). After 72 hours of culture, compared with those in negative control group, the cells in the three groups treated with sodium ferulate showed varying degrees of nuclear pyknosis, fracture, or lysis, and chromatin loss. In the cytoplasm, mitochondria were swollen, the rough endoplasmic reticulum was expanded, and local vacuolation gradually appeared. After 72 hours of culture, compared with that in negative control group, the apoptosis indexes of cells were increased significantly in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group (P<0.05 or P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expressions of Bcl-2 of cells in 0.300 mg/mL sodium ferulate group was significantly decreased (P<0.01), the protein expressions of Bax of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.05), and the protein expression of caspase-3 of cells in 0.300 mg/mL sodium ferulate group was significantly increased (P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expression levels of TGF-β1, phosphorylated Smad2/3, and phosphorylated Smad4 of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly decreased (P<0.05 or P<0.01), and the protein expression levels of phosphorylated Smad7 of cells in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.01). Conclusions: Sodium ferulate can inhibit the proliferation of HSFbs of human skin and promote the apoptosis of HSFbs of human skin by blocking the expression of key proteins on the TGF-β/Smad signaling pathway and synergistically activating the mitochon- drial apoptosis pathway.

Effects of prolonged treatment of TGF-βR inhibitor SB431542 on radiation-induced signaling in breast cancer cells

PURPOSE

We have earlier characterized increased TGF-β signaling in radioresistant breast cancer cells. In this study, we wanted to determine the effect of prolonged treatment of TGF-βR inhibitor SB431542 on radiation-induced signaling, viz., genes regulating apoptosis, EMT, anti and pro-inflammatory cytokines.

MATERIALS AND METHODS

Breast cancer cells were pretreated with TGF-βR inhibitor (SB 431542) followed by exposure to 6 Gy and recovery period of 7 days (D7-6G). We assessed cell survival by MTT assay, cytokines by ELISA and expression analysis by RT-PCR, flow cytometry, and western blot. We carried out migration assays using trans well inserts. We performed bioinformatics analyses of human cancer database through cBioportal.

RESULTS

There was an upregulation of TGF-β1 and 3 and downregulation of TGF-β2, TGF-βR1, and TGF-βR2 in invasive breast carcinoma samples compared to normal tissue. TGF-β1 and TNF-α was higher in radioresistant D7-6G cells with upregulation of pSMAD3, pNF-kB, and ERK signaling. Pretreatment of D7-6G cells with TGF-βR inhibitor SB431542 abrogated pSMAD3, increased proliferation, and migration along with an increase in apoptosis and pro-apoptotic genes. This was associated with hybrid E/M phenotype and downregulation of TGF-β downstream genes, HMGA2 and Snail. There was complete agreement in the expression of mRNA and protein data in genes like vimentin, Snail and HMGA2 in different treatment groups. However, there was disagreement in expression of mRNA and protein in genes like Bax, Bcl-2, E-cadherin, Zeb-1 among the different treatment groups indicating post-transcriptional and post-translational processing of these proteins. Treatment of cells with only SB431542 also increased expression of some E/M genes indicating TGF-β independent effects. Increased IL-6 and IL-10 secretion by SB431542 along with increase in pSTAT3 and pCREB1 could probably explain these TGF-β/Smad3 independent effects.

CONCLUSION

These results highlight that TGF-β-pSMAD3 and TNF-α-pNF-kB are the predominant signaling pathways in radioresistant cells and possibility of some TGF-β/Smad3 independent effects on prolonged treatment with the drug SB431542.

Role of collagen regulators in cancer treatment: A comprehensive review

Abstract:

Collagen is the most important structural protein and also a main component of extra-cellular matrix (ECM). It plays a role in tumor progression. Collagen can be regulated by altering it’s biosynthesis pathway through various signaling pathways, receptors and genes. Activity of cancer cells can also be regulated by other ECM components like metalloproteinases, hyaluronic acid, fibronectin and so on. Hypoxia is also one of the condition which leads to cancer progression by stimulating the expression of procollagen lysine as a collagen crosslinker, which increases the size of collagen fibres promoting cancer spread. The collagen content in cancerous cells leads to resistance in chemotherapy. So, to reduce this resistance, some of the collagen regulating therapies are introduced, which include inhibiting its biosynthesis, disturbing cancer cell signaling pathway, mediating ECM components and directly utilizing collagenase. This study is an effort to compile the strategies reported to control the collagen level and different collagen inhibitors reported so far. More research is needed in this area, growing understandings of collagen’s structural features and its role in cancer progression will aid in the advancement of newer chemotherapies.

Association of B-cell lymphoma 2/microRNA-497 gene expression ratio score with metastasis in patients with colorectal cancer: A propensity-matched cohort analysis

Background

Deregulated microRNAs (miRs) significantly impact cancer development and progression. Our in silico analysis revealed that miR‐497 and its target gene B‐cell lymphoma‐2 (BCL2) could be related to poor cancer outcomes.

Purpose

To investigate the BCL2/miRNA‐497 expression ratio in colorectal cancer (CRC) and explore its association with the clinicopathological characteristics and CRC prognosis.

Methods

Archived samples from 106 CRC patients were enrolled. MiR‐497 and BCL2 gene expressions were detected by Taq‐Man Real‐Time quantitative polymerase chain reaction in propensity‐matched metastatic and nonmetastatic cohorts after elimination of confounder bias.

Results

B‐cell lymphoma‐2 gene was upregulated in metastatic samples (median = 1.16, 95%CI = 1.09–1.60) compared to nonmetastatic (median = 1.02, 95%CI = 0.89–1.25, p < 0.001). In contrast, lower levels of miR‐495 were detected in specimens with distant metastasis (median = 0.05, 95%CI = 0.04–0.20) than nonmetastatic samples (median = 0.54, 95%CI = 0.47–0.58, p < 0.001). Estimated BCL2/miR‐497 ratio yielded a significant differential expression between the two cohort groups. Higher scores were observed in metastasis group (median = 1.39, 95%CI = 0.9–1.51) than nonmetastatic patients (median = 0.29, 95%CI = 0.19–0.39, p < 0.001). Receiver operating characteristic curve analysis showed BCL2/miR‐497 ratio score to have the highest predictive accuracy for metastasis at presentation. The area under the curve was 0.90 (95%CI = 0.839–0.964, p < 0.001) at cut‐off of >0.525, with high sensitivity 81.1% (95%CI = 68.6%–89.4%) and specificity 92.5% (95%CI = 82.1%–97.0%). Also, the ratio score was negatively correlated with disease‐free survival (r = −0.676, p < 0.001) and overall survival times (r = −0.650, p < 0.001). Kaplan–Meier curves showed lower survival rates in cohorts with high‐score compared to low‐score patients.

Conclusion

The BCL2/miR497 expression ratio is associated with poor CRC prognosis in terms of metastasis and short survival.

Ki20227 aggravates apoptosis, inflammatory response, and oxidative stress after focal cerebral ischemia injury

The survival of microglia depends on the colony-stimulating factor-1 receptor (CSF1R) signaling pathway under physiological conditions. Ki20227 is a highly selective CSF1R inhibitor that has been shown to change the morphology of microglia. However, the effects of Ki20227 on the progression of ischemic stroke are unclear. In this study, male C57BL/6 mouse models of focal cerebral ischemic injury were established through the occlusion of the middle cerebral artery and then administered 3 mg/g Ki20227 for 3 successive days. The results revealed that the number of ionized calcium-binding adaptor molecule 1/bromodeoxyuridine double positive cells in the infarct tissue was reduced, the degree of edema was increased, neurological deficits were aggravated, infarct volume was increased, and the number of peri-infarct Nissl bodies was reduced. The number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells in the peri-infarct tissue was increased. The expression levels of Bax and Cleaved caspase-3 were up-regulated. Bcl-2 expression was downregulated. The expression levels of inflammatory factors and oxidative stress-associated factors were increased. These findings suggested that Ki20227 blocked microglial proliferation and aggravated the pathological progression of ischemia/reperfusion injury in a transient middle cerebral artery occlusion model. This study was approved by the Animal Ethics Committee of Lanzhou University Second Hospital (approval No. D2020-68) on March 6, 2020.

Mechanism of Baclofen Inhibiting the Proliferation and Metastasis of GBM by Regulating YAP

This study explores the effect of baclofen on the malignant phenotype of glioblastoma (GBM) and the growth of xenograft tumors and investigates the related mechanisms, aiming to reveal the effect of baclofen on the occurrence and development of GBM. The development of new therapeutic drugs for GBM lays a theoretical and experimental foundation. Research results show that baclofen could inhibit GBM cell proliferation and migration and promote GBM cell apoptosis; baclofen dose- and time-dependently could induce GBM cell YAP phosphorylation. YAP participated in the effect of baclofen on GBM cell proliferation and migration inhibition. Baclofen induced YAP phosphorylation in GBM cells through the GABABR2-Gs-Lats1/2 signaling pathway. Baclofen could inhibit the expression of survivin and Bcl2. Baclofen inhibits subcutaneous tumors by inducing YAP phosphorylation in vivo.

Posttranscriptional regulation of Nrf2 through miRNAs and their role in Alzheimer's disease

The nuclear factor erythroid-derived 2-related factor 2 (NFE2L2/Nrf2) is a pivotal facilitator of cytoprotective responses against the oxidative/electrophilic insults. Upon activation, Nrf2 induces transcription of a wide range of cytoprotective genes having antioxidant response element (ARE) in their promoter region. Dysfunction in Nrf2 signaling has been linked to the pathogenesis of AD and several studies have suggested that boosting Nrf2 expression/activity by genetic or pharmacological approaches is beneficial in AD. Among the diverse mechanisms that regulate the Nrf2 signaling, miRNAs-mediated regulation of Nrf2 has gained much attention in recent years. Several miRNAs have been reported to directly repress the post-transcriptional expression of Nrf2 and thereby negatively regulate the Nrf2-dependent cellular cytoprotective response in AD. Moreover, several Nrf2 targeting miRNAs are misregulated in AD brains. This review is focused on the role of misregulated miRNAs that directly target Nrf2, in AD pathophysiology. Here, alongside a general description of functional interactions between miRNAs and Nrf2, we have reviewed the evidence indicating the possible role of these miRNAs in AD pathogenesis.

Prediction of Rhizoma Drynariae Targets in the Treatment of Osteoarthritis Based on Network Pharmacology and Experimental Verification

Rhizoma Drynariae has been widely used for the treatment of osteoarthritis (OA), but its potential targets and molecular mechanisms remain to be further explored. Targets of Rhizoma Drynariae and OA were predicted by relevant databases, and a protein-protein interaction (PPI) network was constructed to identify key targets. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed to obtain related pathways and then select significant pathways associated with OA. The OA chondrocyte model was established by inflammatory factor-induced SW1353 chondrocytes, and molecular docking was conducted to verify the above theoretical prediction. The results showed that a total of 86 Rhizoma Drynariae-OA interaction targets were identified, among which IL-6 and AKT1 were the key targets in the PPI network. Luteolin was the most critical component of Rhizoma Drynariae. KEGG results indicated that the effects of Rhizoma Drynariae on OA are associated with the PI3K/AKT, TNF, IL-17, apoptosis, and HIF-1 signaling pathway. The PI3K/AKT pathway can activate the downstream NF-κB pathway and further regulate the transcription and expression of downstream IL-6, IL-17, HIF-1α, Bax, and TNF, suggesting that the PI3K/AKT/NF-κB pathway is the critical pathway in the treatment of OA with Rhizoma Drynariae. Active components of Rhizoma Drynariae and key proteins of the PI3K/AKT/NF-κB signaling pathway were subjected to molecular docking, whose results showed that luteolin and IKK-α played a critical role. In vitro experiments indicated that both aqueous extracts of Rhizoma Drynariae (AERD) and luteolin inhibited the expression of IL-6 and HIF-1α and suppressed the activation of PI3K/AKT/NF-κB, IL-17, and TNF pathways. The measurement of mitochondrial membrane potential (Δψm) indicated that AERD and luteolin can decrease the LPS-induced early apoptotic cells. Luteolin had a more prominent inhibitory effect than AERD in the abovementioned in vitro experiments. In conclusion, the therapeutic mechanism of Rhizoma Drynariae against OA may be closely related to the inhibition of the PI3K/AKT/NF-κB pathway and downstream pathways, and luteolin plays a vital role in the treatment.

The effect of AAV-mediated downregulation of Claudin-3 on the development of mouse retinal vasculature

Retinal vascular development is a very tightly regulated and organized process of vessel formation and regression to generate the mature vasculature system. Claudin-3 has been found to be required for the normal development of the neural retina and its vessels in zebrafish in our recent study. In this study, we investigated whether Claudin-3 played a role in the development of mouse retinal vasculature. Immunofluorescent staining was performed to detect the expression and localization of Claudin-3 in the mouse retina. Intravitreal injection of a recombinant adeno-associated virus (AAV) expressing a short hairpin RNA targeting Claudin-3 mRNA was performed to down-regulate Claudin-3 expression in retina in neonatal (Postnatal Day 3, P3) C57BL/6J mice. Retinal vessels were examined by isolectin B4 immunofluorescent staining on the whole-mount retinas and frozen retinal sections at P10. The apoptotic retinal ganglion cells (RGCs) were measured by TdT-mediated dUTP nick-end labelling (TUNEL) staining. Vascular endothelial growth factor A (VEGF-A) expression was detected by immunofluorescent staining. The protein levels of Claudin-3, VEGF-A and B cell lymphoma 2 (Bcl-2) were evaluated by Western blot at P7, P10 and P14. We found that Claudin-3 mainly expressed in the RGCs and progressively increased during the retinal development. The AAV-mediated downregulation of Claudin-3 at P3 impeded the development of retinal deep vascularization of P10 mouse, but without effect on the development of the retinal superficial plexus. Claudin-3 knockdown increased RGC apoptosis and reduced the expression of VEGF-A and Bcl-2 in the retinas. These results suggested that the downregulation of Claudin-3 induced RGC apoptosis and impeded the mouse retinal vascular development by downregulating the levels of VEGF-A and Bcl-2.

Dexmedetomidine inhibits mitochondria damage and apoptosis of enteric glial cells in experimental intestinal ischemia/reperfusion injury via SIRT3-dependent PINK1/HDAC3/p53 pathway

BACKGROUND

Intestinal ischemia/reperfusion (I/R) injury commonly occurs during perioperative periods, resulting in high morbidity and mortality on a global scale. Dexmedetomidine (Dex) is a selective α2-agonist that is frequently applied during perioperative periods for its analgesia effect; however, its ability to provide protection against intestinal I/R injury and underlying molecular mechanisms remain unclear.

METHODS

To fill this gap, the protection of Dex against I/R injury was examined in a rat model of intestinal I/R injury and in an inflammation cell model, which was induced by tumor necrosis factor-alpha (TNF-α) plus interferon-gamma (IFN-γ) stimulation.

RESULTS

Our data demonstrated that Dex had protective effects against intestinal I/R injury in rats. Dex was also found to promote mitophagy and inhibit apoptosis of enteric glial cells (EGCs) in the inflammation cell model. PINK1 downregulated p53 expression by promoting the phosphorylation of HDAC3. Further studies revealed that Dex provided protection against experimentally induced intestinal I/R injury in rats, while enhancing mitophagy, and suppressing apoptosis of EGCs through SIRT3-mediated PINK1/HDAC3/p53 pathway in the inflammation cell model.

CONCLUSION

Hence, these findings provide evidence supporting the protective effect of Dex against intestinal I/R injury and its underlying mechanism involving the SIRT3/PINK1/HDAC3/p53 axis.

Interplay between protein acetylation and ubiquitination controls MCL1 protein stability

The anti-apoptotic myeloid cell leukemia 1 (MCL1) protein belongs to the pro-survival BCL2 family and is frequently amplified or elevated in human cancers. MCL1 is highly unstable, with its stability being regulated by phosphorylation and ubiquitination. Here, we identify acetylation as another critical post-translational modification regulating MCL1 protein stability. We demonstrate that the lysine acetyltransferase p300 targets MCL1 at K40 for acetylation, which is counteracted by the deacetylase sirtuin 3 (SIRT3). Mechanistically, acetylation enhances MCL1 interaction with USP9X, resulting in deubiquitination and subsequent MCL1 stabilization. Therefore, ectopic expression of acetylation-mimetic MCL1 promotes apoptosis evasion of cancer cells, enhances colony formation potential, and facilitates xenografted tumor progression. We further demonstrate that elevated MCL1 acetylation sensitizes multiple cancer cells to pharmacological inhibition of USP9X. These findings reveal that acetylation of MCL1 is a critical post-translational modification enhancing its oncogenic function and provide a rationale for developing innovative therapeutic strategies for MCL1-dependent tumors.

MCL1, an anti-apoptotic BCL2 family protein, is frequently overexpressed in a variety of cancers, and its oncogenic function is finely regulated by post-translational modifications such as phosphorylation and ubiquitination. Shimizu et al. dissect the molecular mechanism of acetylation-mediated MCL1 stability control, providing insights into potential therapeutic intervention targeting the MCL1 protein.

Crotalus atrox venom-induced cellular toxicity: Early wound progression involves reactive oxygen species

Understanding the mechanisms that produce cellular cytotoxicity is fundamental in the field of toxicology. Cytotoxic stimuli can include organic toxins such as hemorrhagic snake venom, which can lead to secondary complications such as the development of necrotic tissue and profuse scarring. These clinical manifestations mimic cytotoxic responses induce by other organic compounds such as organic acids. We used hemorrhagic snake venom and human embryonic kidney cells (HEK 293T) as a model system to better understand the cellular responses involved in venom induced cytotoxicity. Cells stimulated with Crotalus atrox (CA) (western diamondback) venom for 4 or 10 h demonstrated significant cytotoxicity. Results from 2',7'-Dichlorodihydrofluorescein diacetate (H₂ DCF-DA) assays determine CA venom stimulation induces a robust production of reactive oxygen species (ROS) over a 3-h time course. In contrast, pretreatment with polyethylene glycol (PEG)-catalase or N-acetyl cysteine (NAC) prior to CA venom stimulation significantly blunted H₂ DCFDA fluorescence fold changes and showed greater cytoprotective effects than cells stimulated with CA venom alone. Pre- incubating HEK293T cells with the NADPH oxidase (NOX) pan-inhibitor VAS2870 prior venom stimulation significantly minimized the venom-induced oxidative burst at early timepoints (≤2 h). Collectively, our experiments show that pre-application of antioxidants reduces CA venom induce cellular toxicity. This result highlights the importance of ROS in the early stages of cytotoxicity and suggests muting ROS production in noxious injuries may increase positive clinical outcomes.

Pioglitazone mediates apoptosis in Caki cells via downregulating c-FLIP(L) expression and reducing Bcl-2 protein stability

Pioglitazone is an anti-diabetic agent used in the treatment of type 2 diabetes, which belongs to the thiazolidinediones (TZDs) group. TZDs target peroxisome proliferator-activated receptor γ (PPARγ), which functions as a transcription factor of the nuclear hormone receptor. Pioglitazone has antitumor effects in several cancer types and could be a tool for drug therapy in various cancer treatments. Nevertheless, the molecular basis for pioglitazone-induced anticancer effects in renal cancer (RC) has not yet been elucidated. Thus, the aim of the present study was to investigate the detailed signaling pathway underlying pioglitazone-induced apoptosis in Caki cells derived from human clear cell renal cell carcinoma. As a result, it was demonstrated by flow cytometry analysis and Annexin V-propidium iodide staining that pioglitazone treatment induced apoptotic cell death in a dose-dependent manner in Caki cells. The protein expression levels of cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (c-FLIP)_(L) and Bcl-2, which were determined by western blotting, decreased after pioglitazone treatment in Caki cells. Flow cytometry and western blot analyses demonstrated that pioglitazone-mediated apoptosis was blocked following pretreatment with the pan-caspase inhibitor, z-VAD-fmk, indicating that pioglitazone-induced apoptosis was mediated via a caspase-dependent signaling pathway. However, the reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC), did not affect pioglitazone-mediated apoptosis and degradation of c-FLIP_(L) and Bcl-2 protein. Of note, it was found by western blot analysis that Bcl-2 protein expression was downregulated by the decreased protein stability of Bcl-2 in pioglitazone-treated Caki cells. In conclusion, these findings indicated that pioglitazone-induced apoptosis is regulated through caspase-mediated degradation of FLIP_(L) and reduction of Bcl-2 protein stability, suggesting that pioglitazone is a feasible apoptotic agent that could be used in the treatment of human RC.

The multiple mechanisms of MCL1 in the regulation of cell fate

MCL1 (myeloid cell leukemia-1) is a widely recognized pro-survival member of the Bcl-2 (B-cell lymphoma protein 2) family and a promising target for cancer therapy. While the role MCL1 plays in apoptosis is well defined, its participation in emerging non-apoptotic signaling pathways is only beginning to be appreciated. Here, we synthesize studies characterizing MCL1s influence on cell proliferation, DNA damage response, autophagy, calcium handling, and mitochondrial quality control to highlight the broader scope that MCL1 plays in cellular homeostasis regulation. Throughout this review, we discuss which pathways are likely to be impacted by emerging MCL1 inhibitors, as well as highlight non-cancerous disease states that could deploy Bcl-2 homology 3 (BH3)-mimetics in the future.

In this review Widden and Placzek synthesize studies characterizing the influence that myeloid cell leukemia-1 (MCL1) has on cell proliferation, DNA damage response, autophagy, calcium handling, and mitochondrial quality control to highlight the broader scope that it plays in cellular homeostasis regulation. They discuss which pathways are likely to be impacted by emerging MCL1 inhibitors, as well as highlight non-cancerous disease states that could deploy BH3-mimetics in the future.

The Emerging Role of Stress Granules in Hepatocellular Carcinoma

Stress granules (SGs) are small membrane-free cytosolic liquid-phase ordered entities in which mRNAs are protected and translationally silenced during cellular adaptation to harmful conditions (e.g., hypoxia, oxidative stress). This function is achieved by structural and functional SG components such as scaffold proteins and RNA-binding proteins controlling the fate of mRNAs. Increasing evidence indicates that the capacity of cells to assemble/disassemble functional SGs may significantly impact the onset and the development of metabolic and inflammatory diseases, as well as cancers. In the liver, the abnormal expression of SG components and formation of SG occur with chronic liver diseases, hepatocellular carcinoma (HCC), and selective hepatic resistance to anti-cancer drugs. Although, the role of SG in these diseases is still debated, the modulation of SG assembly/disassembly or targeting the expression/activity of specific SG components may represent appealing strategies to treat hepatic disorders and potentially cancer. In this review, we discuss our current knowledge about pathophysiological functions of SGs in HCC as well as available molecular tools and drugs capable of modulating SG formation and functions for therapeutic purposes.

Neuroprotective Effect of 4-Phenylbutyric Acid against Photo-Stress in the Retina

Exposure to excessive visible light causes retinal degeneration and may influence the progression of retinal blinding diseases. However, there are currently no applied treatments. Here, we focused on endoplasmic reticulum (ER) stress, which can cause cellular degeneration and apoptosis in response to stress. We analyzed functional, histological, and molecular changes in the light-exposed retina and the effects of administering an ER-stress inhibitor, 4-phenylbutyric acid (4-PBA), in mice. We found that light-induced visual function impairment related to photoreceptor cell loss and outer segment degeneration were substantially suppressed by 4-PBA administration, following attenuated photoreceptor apoptosis. Induction of retinal ER stress soon after light exposure, represented by upregulation of the immunoglobulin heavy chain binding protein (BiP) and C/EBP-Homologous Protein (CHOP), were suppressed by 4-PBA. Concurrently, light-induced oxidative stress markers, Nuclear factor erythroid 2-related factor 2 (Nrf2) and Heme Oxygenase 1 (HO-1), and mitochondrial apoptotic markers, B-cell lymphoma 2 apoptosis regulator (Bcl-2)-associated death promoter (Bad), and Bcl-2-associated X protein (Bax), were suppressed by 4-PBA administration. Increased expression of glial fibrillary acidic protein denoted retinal neuroinflammation, and inflammatory cytokines were induced after light exposure; however, 4-PBA acted as an anti-inflammatory. Suppression of ER stress by 4-PBA may be a new therapeutic approach to suppress the progression of retinal neurodegeneration and protect visual function against photo-stress.

Mcl-1 Inhibition: Managing Malignancy in Multiple Myeloma

Multiple myeloma (MM) is a plasma cells neoplasm. The overexpression of Bcl-2 family proteins, particularly myeloid cell leukemia 1 (Mcl-1), plays a critical role in the pathogenesis of MM. The overexpression of Mcl-1 is associated with drug resistance and overall poor prognosis of MM. Thus, inhibition of the Mcl-1 protein considered as a therapeutic strategy to kill the myeloma cells. Over the last decade, the development of selective Mcl-1 inhibitors has seen remarkable advancement. This review presents the critical role of Mcl-1 in the progression of MM, the most prominent BH3 mimetic and semi-BH3 mimetic that selectively inhibit Mcl-1, and could be used as single agent or combined with existing therapies.