New frontiers in promoting tumour cell death: targeting apoptosis, necroptosis and autophagy

Selective Targeting of Regulated Rhabdomyosarcoma Cells by Trinuclear Ruthenium(II)-Arene Complexes

The use of benzimidazole-based trinuclear ruthenium(II)-arene complexes (1-3) to selectively target the rare cancer rhabdomyosarcoma is reported. Preliminary cytotoxic evaluations of the ruthenium complexes in an eight-cancer cell line panel revealed enhanced, selective cytotoxicity toward rhabdomyosarcoma cells (RMS). The trinuclear complex 1 was noted to show superior short- and long-term cytotoxicity in RMS cell lines and enhanced selectivity relative to cisplatin. Remarkably, 1 inhibits the migration of metastatic RMS cells and maintains superior activity in a 3D multicellular spheroid model in comparison to that of the clinically used cisplatin. Mechanistic insights reveal that 1 effectively induces genomic DNA damage, initiates autophagy, and prompts the intrinsic and extrinsic apoptotic pathways in RMS cells. To the best of our knowledge, 1 is the first trinuclear ruthenium(II) arene complex to selectively kill RMS cells in 2D and 3D cell cultures.

Anti-IL-8 monoclonal antibodies inhibits the autophagic activity and cancer stem cells maintenance within breast cancer tumor microenvironment

BACKGROUND

Breast cancer tumor microenvironment (TME) is a promising target for immunotherapy. Autophagy, and cancer stem cells (CSCs) maintenance are essential processes involved in tumorigenesis, tumor survival, invasion, and treatment resistance. Overexpression of angiogenic chemokine interleukin-8 (IL-8) in breast cancer TME is associated with oncogenic signaling pathways, increased tumor growth, metastasis, and poor prognosis.

OBJECTIVE

Thus, we aimed to investigate the possible anti-tumor effect of neutralizing antibodies against IL-8 by evaluating its efficacy on autophagic activity and breast CSC maintenance.

METHODS

IL-8 monoclonal antibody supplemented tumor tissue culture systems from 15 females undergoing mastectomy were used to evaluate the expression of LC3B as a specific biomarker of autophagy and CD44, CD24 as cell surface markers of breast CSCs using immunofluorescence technique.

RESULTS

Our results revealed that anti-IL-8 mAb significantly decreased the level of LC3B in the cultured tumor tissues compared to its non-significant decrease in the normal breast tissues.Anti-IL-8 mAb also significantly decreased the CD44 expression in either breast tumors or normal cultured tissues. While it caused a non-significant decrease in CD24 expression in cultured breast tumor tissue and a significant decrease in its expression in the corresponding normal ones.

CONCLUSIONS

Anti-IL-8 monoclonal antibody exhibits promising immunotherapeutic properties through targeting both autophagy and CSCs maintenance within breast cancer TME.

Triggering endogenous Z-RNA sensing for anti-tumor therapy through ZBP1-dependent necroptosis

ZBP1 senses viral Z-RNAs to induce necroptotic cell death to restrain viral infection. ZBP1 is also thought to recognize host cell-derived Z-RNAs to regulate organ development and tissue inflammation in mice. However, it remains unknown how the host-derived Z-RNAs are formed and how these endogenous Z-RNAs are sensed by ZBP1. Here, we report that oxidative stress strongly induces host cell endogenous Z-RNAs, and the Z-RNAs then localize to stress granules for direct sensing by ZBP1 to trigger necroptosis. Oxidative stress triggers dramatically increase Z-RNA levels in tumor cells, and the Z-RNAs then directly trigger tumor cell necroptosis through ZBP1. Localization of the induced Z-RNAs to stress granules is essential for ZBP1 sensing. Oxidative stress-induced Z-RNAs significantly promote tumor chemotherapy via ZBP1-driven necroptosis. Thus, our study identifies oxidative stress as a critical trigger for Z-RNA formation and demonstrates how Z-RNAs are directly sensed by ZBP1 to trigger anti-tumor necroptotic cell death.

RIPK1 polymorphisms and expression levels: impact on genetic susceptibility and clinical outcome of epithelial ovarian cancer

BACKGROUND

The aim of this study was to explore the associations of RIPK1 polymorphisms, plasma levels and mRNA expression with susceptibility to epithelial ovarian cancer (EOC) and clinical outcome.

METHODS

Three hundred and nineteen EOC patients included in a 60-month follow-up program and 376 controls were enrolled. Two tag SNPs (rs6907943 and rs9392453) of RIPK1 were genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. Plasma levels of RIPK1 and RIPK1 mRNA expression in white blood cells were determined by ELISA and qPCR, respectively.

RESULTS

For rs9392453, significantly increased EOC risk was found to be associated with C allele (P = 0.002, OR = 1.49, 95%CI  1.15-1.92), and with CT/CC genotypes in the dominant genetic model (P = 0.006, OR = 1.54, 95%CI  1.12-2.08). CC haplotype (rs6907943-rs9392453) was associated with increased EOC susceptibility. CC genotype of rs6907943 and CT/CC genotypes of rs9392453 were associated with early onset (age ≤ 50 years) of EOC (OR = 2.5, 95%CI  1.03-5.88, and OR = 1.64, 95%CI  1.04-2.63, respectively). AC genotype of rs6907943 was associated with better overall survival of EOC patients in the over-dominant genetic model (P = 0.035, HR = 0.41, 95%CI  0.18-0.94). Multivariate survival analysis identified the AC genotype of rs6907943 as an independent protective factor for survival of early onset patients (P = 0.044, HR = 0.12, 95%CI  0.02-0.95). Compared to controls, significantly increased plasma levels of RIPK1 and reduced RIPK1 mRNA expression were observed in patients.

CONCLUSIONS

Our results suggest that tag SNPs of RIPK1, increased plasma levels of RIPK1 protein and reduced RIPK1 mRNA expression in white blood cells, may influence the susceptibility to EOC. SNP rs6907943 may be a useful marker to distinguish EOC patients with high risk of death.

Enabling, Decagram-Scale Synthesis of Macrocyclic MCL-1 Inhibitor ABBV-467

ABBV-467 is a highly potent and selective MCL-1 inhibitor that was advanced to a phase I clinical trial for the treatment of multiple myeloma. Due to its large size and structural complexity, ABBV-467 is a challenging synthetic target. Herein, we describe the synthesis of ABBV-467 on a decagram scale, which enabled preclinical characterization. The strategy is convergent and stereoselective, featuring a hindered biaryl cross coupling, enantioselective hydrogenation, and conformationally preorganized macrocyclization by C-O bond formation as key steps.

Types of Cell Death from a Molecular Perspective

The former conventional belief was that cell death resulted from either apoptosis or necrosis; however, in recent years, different pathways through which a cell can undergo cell death have been discovered. Various types of cell death are distinguished by specific morphological alterations in the cell's structure, coupled with numerous biological activation processes. Various diseases, such as cancers, can occur due to the accumulation of damaged cells in the body caused by the dysregulation and failure of cell death. Thus, comprehending these cell death pathways is crucial for formulating effective therapeutic strategies. We focused on providing a comprehensive overview of the existing literature pertaining to various forms of cell death, encompassing apoptosis, anoikis, pyroptosis, NETosis, ferroptosis, autophagy, entosis, methuosis, paraptosis, mitoptosis, parthanatos, necroptosis, and necrosis.

A novel mitochondria-targeting compound exerts therapeutic effects against melanoma by inducing mitochondria-mediated apoptosis and autophagy in vitro and in vivo

Melanoma is the most invasive skin cancer, with a high mortality rate. However, existing therapeutic drugs have side effects, low reactivity, and lead to drug resistance. As the power source in cells, mitochondria play an important role in the survival of cancer cells and are an important target for tumor therapy. This study aimed to develop a new anti-melanoma compound that targets mitochondria, evaluate its effect on the proliferation and metastasis of melanoma cells, and explore its mechanism of action. The novel mitochondria-targeting compound, SCZ0148, was synthesized by modifying the structure of cyanine. Then, A375 and B16 cells were incubated with different concentrations of SCZ0148, and different doses of SCZ0148 were administered to A375 and B16 xenograft zebrafish. The results showed that SCZ0148 targeted mitochondria, had dose- and time-dependent effects on the proliferation of melanoma cell lines, and had no obvious side effects on normal cells. In addition, SCZ0148 induced melanoma cell apoptosis through the reactive oxygen species-mediated mitochondrial pathway of apoptosis and promoted autophagy. SCZ0148 significantly inhibited the migration of melanoma cells via a matrix metalloprotein 9-mediated pathway. Similarly, SCZ0148 inhibited melanoma cell proliferation in a concentration-dependent manner in vivo. In summary, SCZ0148 may be a novel anti-melanoma compound that targets mitochondria.

Molecular subtypes of lung adenocarcinoma patients for prognosis and therapeutic response prediction with machine learning on 13 programmed cell death patterns

BACKGROUND

Lung adenocarcinoma (LUAD) seriously threatens people's health worldwide. Programmed cell death (PCD) plays a critical role in regulating LUAD growth and metastasis as well as in therapeutic response. However, currently, there is a lack of integrative analysis of PCD-related signatures of LUAD for accurate prediction of prognosis and therapeutic response.

METHODS

The bulk transcriptome and clinical information of LUAD were obtained from TCGA and GEO databases. A total of 1382 genes involved in regulating 13 various PCD patterns (apoptosis, necroptosis, pyroptosis, ferroptosis, cuproptosis, netotic cell death, entotic cell death, lysosome-dependent cell death, parthanatos, autophagy-dependent cell death, oxeiptosis, alkaliptosis and disulfidptosis) were included in the study. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were performed to identify PCD-associated differential expression genes (DEGs). An unsupervised consensus clustering algorithm was used to explore the potential subtypes of LUAD based on the expression profiles of PCD-associated DEGs. Univariate Cox regression analysis, Least Absolute Shrinkage and Selection Operator (LASSO) regression, Random Forest (RF) analysis and stepwise multivariate Cox analysis were performed to construct a prognostic gene signature. The "oncoPredict" algorithm was utilized for drug-sensitive analysis. GSVA and GSEA were utilized to perform function enrichment analysis. MCPcounter, quanTIseq, Xcell and ssGSEA algorithms were used for tumor immune microenvironment analysis. A nomogram incorporating PCDI and clinicopathological characteristics was established to predict the prognosis of LUAD patients.

RESULTS

Forty PCD-associated DEGs related to LUAD were obtained by WGCNA analysis and differential expression analysis, followed by unsupervised clustering to identify two LUAD molecular subtypes. A programmed cell death index (PCDI) with a five-gene signature was established by machine learning algorithms. LUAD patients were then divided into a high PCDI group and a low PCDI group using the median PCDI as a cutoff. Survival and therapeutic analysis revealed that the high PCDI group had a poor prognosis and was more sensitive to targeted drugs but less sensitive to immunotherapy compared to the low PCDI group. Further enrichment analysis showed that B cell-related pathways were significantly downregulated in the high PCDI group. Accordingly, the decreased tumor immune cell infiltration and the lower tumor tertiary lymphoid structure (TLS) scores were also found in the high PCDI group. Finally, a nomogram with reliable predictive performance PCDI was constructed by incorporating PCDI and clinicopathological characteristics, and a user-friendly online website was established for clinical reference ( https://nomogramiv.shinyapps.io/NomogramPCDI/ ).

CONCLUSION

We performed the first comprehensive analysis of the clinical relevance of genes regulating 13 PCD patterns in LUAD and identified two LUAD molecular subtypes with distinct PCD-related gene signature which indicated differential prognosis and treatment sensitivity. Our study provided a new index to predict the efficacy of therapeutic interventions and the prognosis of LUAD patients for guiding personalized treatments.

Gossypetin Is a Novel Modulator of Inflammatory Cytokine Production and a Suppressor of Osteosarcoma Cell Growth

Osteosarcoma (OS) is a common childhood sarcoma, and its treatment is hindered by adverse effects, chemoresistance, and recurrence. Interleukin (IL)-6 production by tumors plays a significant role in inflammation, carcinogenesis, and metastasis. This study aimed to investigate the antiproliferative potential of luteolin derivatives in OS and to evaluate interleukin production. MG-63, Saos-2, HOS, and 143B human OS cell lines were incubated with luteolin and eight derivatives containing hydroxy, chlorine, or alkyl substitutions. The cell viability and growth were evaluated in the presence of these compounds. Apoptosis was also examined through the analysis of the Bax expression and caspase-3 activity. Finally, the gossypetin effects were measured regarding the production of proinflammatory cytokines interleukin (IL)-6, IL-1β, and IL-12p70. Our findings show that gossypetin was the most potent compound, with proliferation-suppressing activities that induced a series of critical events, including the inhibition of the cell viability and growth. Apoptosis was associated with enhanced caspase-3 activity and increased Bax expression, indicating the involvement of the intrinsic pathway of apoptosis. Moreover, pre-/co-treatment with gossypetin significantly reduced the autocrine production of proinflammatory cytokines. Further investigation is required; nevertheless, considering the link between inflammation, carcinogenesis, and metastasis in OS, our findings suggest that gossypetin exhibits anti-proliferative and anti-inflammatory properties that are potentially relevant in the clinical context.

Ocular Surface Allostasis-When Homeostasis Is Lost: Challenging Coping Potential, Stress Tolerance, and Resilience

The loss of ocular surface (OS) homeostasis characterizes the onset of dry eye disease. Resilience defines the ability to withstand this threat, reflecting the ability of the ocular surface to cope with and bounce back after challenging events. The coping capacity of the OS defines the ability to successfully manage cellular stress. Cellular stress, which is central to the outcome of the pathophysiology of dry eye disease, is characterized by intensity, continuity, and receptivity, which lead to the loss of homeostasis, resulting in a phase of autocatalytic dysregulation, an event that is not well-defined. To better define this event, here, we present a model providing a potential approach when homeostasis is challenged and the coping capacities have reached their limits, resulting in the stage of heterostasis, in which the dysregulated cellular stress mechanisms take over, leading to dry eye disease. The main feature of the proposed model is the concept that, prior to the initiation of the events leading to cellular stress, there is a period of intense activation of all available coping mechanisms preventing the imminent dysregulation of ocular surface homeostasis. When the remaining coping mechanisms and resilience potential have been maximally exploited and have, finally, been exceeded, there will be a transition to manifest disease with all the well-known signs and symptoms, with a shift to allostasis, reflecting the establishment of another state of balance. The intention of this review was to show that it is possibly the phase of heterostasis preceding the establishment of allostasis that offers a better chance for therapeutic intervention and optimized recovery. Once allostasis has been established, as a new steady-state of balance at a higher level of constant cell stress and inflammation, treatment may be far more difficult, and the potential for reversal is drastically decreased. Homeostasis, once lost, can possibly not be fully recovered. The processes established during heterostasis and allostasis require different approaches and treatments for their control, indicating that the current treatment options for homeostasis need to be adapted to a more-demanding situation. The loss of homeostasis necessarily implies the establishment of a new balance; here, we refer to such a state as allostasis.

The Active Fraction of Polyrhachis vicina Roger (AFPR) activates ERK to cause necroptosis in colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Polyrhachis vicina Roger (P. vicina), a traditional Chinese medicinal animal, has been used to treat rheumatoid arthritis, hepatitis, cancer, and other conditions. Due to its anti-inflammatory properties, our previous pharmacological investigations have demonstrated that it is effective against cancer, depression, and hyperuricemia. Nevertheless, the key active components and targets of P. vicina in cancers are still unexplored.

AIM OF THE STUDY

The study aimed to evaluate the pharmacological treatment mechanism of the active fraction of P. vicina (AFPR) in treating colorectal cancer (CRC) and to further reveal its active ingredients and key targets.

METHODS

To examine the inhibitory impact of AFPR on CRC growth, tumorigenesis assays, cck-8 assays, colony formation assays, and MMP detection were utilized. The primary components of AFPR were identified by GC-MS analysis. The network pharmacology, molecular docking, qRT-PCR, western blotting, CCK-8 assays, colony formation assay, Hoechst staining, Annexin V-FITC/PI double staining, and MMP detection were performed to pick out the active ingredients and potential key targets of AFPR. The function of Elaidic acid on necroptosis was investigated through siRNA interference and the utilization of inhibitors. Elaidic acid's effectiveness to suppress CRC growth in vivo was assessed using a tumorigenesis experiment.

RESULTS

Studies confirmed that AFPR prevented CRC from growing and evoked cell death. Elaidic acid was the main bioactive ingredient in AFPR that targeted ERK. Elaidic acid greatly affected the ability of SW116 cells to form colonies, produce MMP, and undergo necroptosis. Additionally, Elaidic acid promoted necroptosis predominantly by activating ERK/RIPK1/RIPK3/MLKL.

CONCLUSION

According to our findings, Elaidic acid is the main active component of AFPR, which induced necroptosis in CRC through the activation of ERK. It represents a promising alternative therapeutic option for CRC. This work provided experimental support for the therapeutic application of P. vicina Roger in the treatment of CRC.

Synergistic Effects of New Curcumin Analog (PAC) and Cisplatin on Oral Cancer Therapy

Oral cancer has traditionally been treated with surgery, radiotherapy, chemotherapy, or a combination of these therapies. Although cisplatin, a chemotherapy drug, can effectively kill oral cancer cells by forming DNA adducts, its clinical use is limited due to adverse effects and chemo-resistance. Therefore, there is a need to develop new, targeted anticancer drugs to complement chemotherapy, allowing for reduced cisplatin doses and minimizing adverse effects. Recent studies have shown that 3,5-Bis (4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidine (PAC), a new curcumin analog, possesses anticancer properties and could be considered a complementary or alternative therapy. In this study, we aimed to assess the potential complementary effects of PAC in combination with cisplatin for treating oral cancer. We conducted experiments using oral cancer cell lines (Ca9-22) treated with different concentrations of cisplatin (ranging from 0.1 μM to 1 μM), either alone or in conjunction with PAC (2.5 and 5 μM). Cell growth was measured using the MTT assay, while cell cytotoxicity was evaluated using an LDH assay. Propidium iodide and annexin V staining were employed to examine the impact on cell apoptosis. Flow cytometry was used to investigate the effects of the PAC/cisplatin combination on cancer cell autophagy, oxidative stress, and DNA damage. Additionally, a Western Blot analysis was performed to assess the influence of this combination on pro-carcinogenic proteins involved in various signaling pathways. The results demonstrated that PAC enhanced the efficacy of cisplatin in a dose-dependent manner, leading to a significant inhibition of oral cancer cell proliferation. Importantly, treatment with PAC (5 μM) alongside different concentrations of cisplatin reduced the IC50 of cisplatin tenfold. Combining these two agents increased apoptosis by further inducing caspase activity. In addition, the concomitant use of PAC and cisplatin enhances oral cancer cell autophagy, ROS, and MitoSOX production. However, combined PAC with cisplatin inhibits the mitochondrial membrane potential (ΔΨm), which is a marker for cell viability. Finally, this combination further enhances the inhibition of oral cancer cell migration via the inhibition of epithelial-to-mesenchymal transition genes, such as E-cadherin. We demonstrated that the combination of PAC and cisplatin markedly enhanced oral cancer cell death by inducing apoptosis, autophagy, and oxidative stress. The data presented indicate that PAC has the potential to serve as a powerful complementary agent to cisplatin in the treatment of gingival squamous cell carcinomas.

Therapeutic advancements in targeting BCL-2 family proteins by epigenetic regulators, natural, and synthetic agents in cancer

Cancer is amongst the deadliest and most disruptive disorders, having a much higher death rate than other diseases worldwide. Human cancer rates continue to rise, thereby posing the most significant concerns for medical health professionals. In the last two decades, researchers have gone past several milestones in tackling cancer while gaining insight into the role of apoptosis in cancer or targeting various biomarker tools for prognosis and diagnosis. Apoptosis which is still a topic full of complexities, can be controlled considerably by B-cell lymphoma 2 (BCL-2) and its family members. Therefore, targeting proteins of this family to prevent tumorigenesis, is essential to focus on the pharmacological features of the anti-apoptotic and pro-apoptotic members, which will help to develop and manage this disorder. This review deals with the advancements of various epigenetic regulators to target BCL-2 family proteins, including the mechanism of several microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Similarly, a rise in natural and synthetic molecules' research over the last two decades has allowed us to acquire insights into understanding and managing the transcriptional alterations that have led to apoptosis and treating various neoplastic diseases. Furthermore, several inhibitors targeting anti-apoptotic proteins and inducers or activators targeting pro-apoptotic proteins in preclinical and clinical stages have been summarized. Overall, agonistic and antagonistic mechanisms of BCL-2 family proteins conciliated by epigenetic regulators, natural and synthetic agents have proven to be an excellent choice in developing cancer therapeutics.

The mechanism of programmed death and endoplasmic reticulum stress in pulmonary hypertension

Pulmonary hypertension (PH) was a cardiovascular disease with high morbidity and mortality. PH was a chronic disease with complicated pathogenesis and uncontrollable factors. PH was divided into five groups according to its pathogenesis and clinical manifestations. Although the treatment and diagnosis of PH has made great progress in the past ten years. However, the diagnosis and prognosis of the PAH had a great contrast, which was not conducive to the diagnosis and treatment of PH. If not treated properly, it will lead to right ventricular failure or even death. Therefore, it was necessary to explore the pathogenesis of PH. The problem we urgently need to solve was to find and develop drugs for the treatment of PH. We reviewed the PH articles in the past 10 years or so as well as systematically summarized the recent advance. We summarized the latest research on the key regulatory factors (pyroptosis, apoptosis, necroptosis, ferroptosis, and endoplasmic reticulum stress) involved in PH. To provide theoretical basis and basis for finding new therapeutic targets and research directions of PH.

The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction

The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets. Regulated cell death (RCD) is an essential process to control the biological homeostasis of tissues and organisms. The identification of different mechanisms of RCD stimulated the research on their involvement in different human pathologies. Whereas apoptosis has been widely studied in DED and included in the DED vicious cycle, the role of RCD still needs to be completely elucidated. In this review, we will explore the potential roles of different types of RCD in DED and ocular surface dysfunction. Starting from the evidence of oxidative stress and inflammation in dry eye pathology, we will analyse the potential therapeutic applications of the following principal RCD mechanisms: ferroptosis, necroptosis, and pyroptosis.

Zinc Acts Synergistically with Berberine for Enhancing Its Efficacy as an Anti-cancer Agent by Inducing Clusterin-Dependent Apoptosis in HT-29 Colorectal Cancer Cells

It is now widely accepted that anti-cancer medications are most effective when administered in combination. Zinc is an essential micronutrient whilst berberine is a well-known natural phytochemical, both having multiple molecular mechanisms of action. The present study aimed to determine the combinatorial effect of zinc and berberine on the human adenocarcinoma HT-29 cancer cell line. The anti-proliferative activity of berberine and zinc was determined by cell viability and colony-forming assays. The combination index and drug reduction index values of zinc and berberine co-treatments were estimated by suitable software. Flow cytometry was used to analyse cell cycle distribution and Annexin V/PI staining. The expression of apoptosis and zinc signalling markers were analysed by RT-qPCR and immunoblot analysis. Berberine decreased the viability of colon cancer cells in a dose-dependent manner whilst zinc alone had no significant influence on it. However, zinc and berberine co-treatment resulted in a synergistic anti-cancer action which was demonstrated by G₂/M phase arrest of cell growth at a lower dose of berberine. Annexin V assay demonstrated that the synergistic impact of zinc and berberine boosted the number of apoptotic cells. Gene expression analysis at both transcriptional and translational levels showed the upregulation of apoptotic (caspase-3 and caspase-8) and a zinc-sensing receptor (GPR39) gene with concomitant downregulation of anti-apoptotic genes like proliferating cell nuclear antigen (PCNA) and clusterin. Our findings showed that the combination of zinc and berberine has synergistic anti-cancer efficacy and thus could be used as a potential chemopreventive option for colon cancer.

Mitochondrial transplantation as a promising therapy for mitochondrial diseases

Mitochondrial diseases are a group of inherited or acquired metabolic disorders caused by mitochondrial dysfunction which may affect almost all the organs in the body and present at any age. However, no satisfactory therapeutic strategies have been available for mitochondrial diseases so far. Mitochondrial transplantation is a burgeoning approach for treatment of mitochondrial diseases by recovery of dysfunctional mitochondria in defective cells using isolated functional mitochondria. Many models of mitochondrial transplantation in cells, animals, and patients have proved effective via various routes of mitochondrial delivery. This review presents different techniques used in mitochondrial isolation and delivery, mechanisms of mitochondrial internalization and consequences of mitochondrial transplantation, along with challenges for clinical application. Despite some unknowns and challenges, mitochondrial transplantation would provide an innovative approach for mitochondrial medicine.

Naturally derived indole alkaloids targeting regulated cell death (RCD) for cancer therapy: from molecular mechanisms to potential therapeutic targets

Regulated cell death (RCD) is a critical and active process that is controlled by specific signal transduction pathways and can be regulated by genetic signals or drug interventions. Meanwhile, RCD is closely related to the occurrence and therapy of multiple human cancers. Generally, RCD subroutines are the key signals of tumorigenesis, which are contributed to our better understanding of cancer pathogenesis and therapeutics. Indole alkaloids derived from natural sources are well defined for their outstanding biological and pharmacological properties, like vincristine, vinblastine, staurosporine, indirubin, and 3,3′-diindolylmethane, which are currently used in the clinic or under clinical assessment. Moreover, such compounds play a significant role in discovering novel anticancer agents. Thus, here we systemically summarized recent advances in indole alkaloids as anticancer agents by targeting different RCD subroutines, including the classical apoptosis and autophagic cell death signaling pathways as well as the crucial signaling pathways of other RCD subroutines, such as ferroptosis, mitotic catastrophe, necroptosis, and anoikis, in cancer. Moreover, we further discussed the cross talk between different RCD subroutines mediated by indole alkaloids and the combined strategies of multiple agents (e.g., 3,10-dibromofascaplysin combined with olaparib) to exhibit therapeutic potential against various cancers by regulating RCD subroutines. In short, the information provided in this review on the regulation of cell death by indole alkaloids against different targets is expected to be beneficial for the design of novel molecules with greater targeting and biological properties, thereby facilitating the development of new strategies for cancer therapy.

TNF Receptor Associated Factor 2 (TRAF2) Signaling in Cancer

Simple Summary

Tumor necrosis factor (TNF) receptor associated factor-2 (TRAF2) is an intracellular adapter protein with E3 ligase activity, which interacts with a plethora of other signaling proteins, including plasma membrane receptors, kinases, phosphatases, other E3 ligases, and deubiquitinases. TRAF2 is involved in various cancer-relevant cellular processes, such as the activation of transcription factors of the NFκB family, stimulation of mitogen-activated protein (MAP) kinase cascades, endoplasmic reticulum (ER) stress signaling, autophagy, and the control of cell death programs. In a context-dependent manner, TRAF2 promotes tumor development but it can also act as a tumor suppressor. Based on a general description, how TRAF2 in concert with TRAF2-interacting proteins and other TRAF proteins act at the molecular level is discussed for its importance for tumor development and its potential usefulness as a therapeutic target in cancer therapy.

Abstract

Tumor necrosis factor (TNF) receptor associated factor-2 (TRAF2) has been originally identified as a protein interacting with TNF receptor 2 (TNFR2) but also binds to several other receptors of the TNF receptor superfamily (TNFRSF). TRAF2, often in concert with other members of the TRAF protein family, is involved in the activation of the classical NFκB pathway and the stimulation of various mitogen-activated protein (MAP) kinase cascades by TNFRSF receptors (TNFRs), but is also required to inhibit the alternative NFκB pathway. TRAF2 has also been implicated in endoplasmic reticulum (ER) stress signaling, the regulation of autophagy, and the control of cell death programs. TRAF2 fulfills its functions by acting as a scaffold, bringing together the E3 ligase cellular inhibitor of apoptosis-1 (cIAP1) and cIAP2 with their substrates and various regulatory proteins, e.g., deubiquitinases. Furthermore, TRAF2 can act as an E3 ligase by help of its N-terminal really interesting new gene (RING) domain. The finding that TRAF2 (but also several other members of the TRAF family) interacts with the latent membrane protein 1 (LMP1) oncogene of the Epstein–Barr virus (EBV) indicated early on that TRAF2 could play a role in the oncogenesis of B-cell malignancies and EBV-associated non-keratinizing nasopharyngeal carcinoma (NPC). TRAF2 can also act as an oncogene in solid tumors, e.g., in colon cancer by promoting Wnt/β-catenin signaling. Moreover, tumor cell-expressed TRAF2 has been identified as a major factor-limiting cancer cell killing by cytotoxic T-cells after immune checkpoint blockade. However, TRAF2 can also be context-dependent as a tumor suppressor, presumably by virtue of its inhibitory effect on the alternative NFκB pathway. For example, inactivating mutations of TRAF2 have been associated with tumor development, e.g., in multiple myeloma and mantle cell lymphoma. In this review, we summarize the various TRAF2-related signaling pathways and their relevance for the oncogenic and tumor suppressive activities of TRAF2. Particularly, we discuss currently emerging concepts to target TRAF2 for therapeutic purposes.

Homoharringtonine combined with cladribine and aclarubicin (HCA) in acute myeloid leukemia: A new regimen of conventional drugs and its mechanism

Objective

The prognosis of children with refractory acute myeloid leukemia (AML) is poor. Complete remission (CR) is not always achieved with current salvage chemotherapy regimens before transplantation, and some patients have no chance of transplantation. Here, we aimed to describe a new regimen of conventional chemotherapy drugs (homoharringtonine, cladribine , and aclarubicin (HCA)) for refractory AML and its mechanism in vitro.

Methods

We retrospectively collected the clinical data of 5 children with primary refractory AML using HCA as reinduction chemotherapy, and CR rates, adverse reactions, and disease-free survival (DFS) were analyzed. The effects of homoharringtonine, cladribine, and aclarubicin alone or in combination on the proliferation of HL60 and THP1 cells were analyzed by CCK-8 assay. Furthermore, CCK-8 was used to determine the effects of HCA, alone or in combination with apoptosis inhibitors, necroptosis inhibitors, ferroptosis inhibitors, or autophagy inhibitors, on the proliferation of HL60 and THP1 cells and to screen for possible HCA-mediated death pathways in AML cells. The pathway of HCA-mediated AML cell death was further verified by Hoechst/PI staining, flow cytometry, and Western blotting.

Results

After 2 cycles of conventional chemotherapy, none of the 5 children with AML achieved CR and were then treated with the HCA regimen for two cycles, 4 of 5 achieved CR, and another child achieved CR with incomplete hematological recovery (CRi). After CR, 3 children underwent hematopoietic stem cell transplantation (HSCT), and only 2 of them received consolidation therapy. As of the last follow-up, all 5 patients had been in DFS for a range of 23 to 28 months. The inhibition rate of homoharringtonine, cladribine, and aclarubicin in combination on HL60 and THP1 cells was significantly greater than that of a single drug or a combination of two drugs. We found that inhibitors of apoptosis and necroptosis were able to inhibit HCA-mediated cell death but not ferroptosis or autophagy inhibitors. Compared with the control group, the number of apoptotic cells in the HCA group was significantly increased and could be reduced by an apoptosis inhibitor. Western blot results showed that PARP, caspase-3, and caspase-8 proteins were activated and cleaved in the HCA group, the expression of Bax was upregulated and that of Bcl-2 was downregulated. The expression of apoptosis-related proteins could be reversed by apoptosis inhibition. Compared with the control group, the expression levels of the necroptosis-related proteins RIP1, RIP3, and MLKL were downregulated in the HCA group but were not phosphorylated. The necroptosis inhibitor increased the expression of RIP1 but caused no significant changes in RIP3 and MLKL, and none were phosphorylated.

Conclusions

HCA, as a new regimen of conventional drugs, was a safe and efficacious reinduction salvage strategy in children with refractory AML before HSCT. HCA exhibits the synergistic growth inhibition of AML cells and induces cell death mainly through apoptosis.

Effects of ethanol and deferoxamine on rat primary glial cell cultures, in regard with ischemia induced by traumatic spinal cord injury

Although they have been regarded, in the past, as passive support cells, many experimental data have shown that glial cells play a critical role in the development and functioning of the nervous system. Despite the advances that have been made in understanding astrocytes' role in the nervous system's development and function, our knowledge of their interactions with other cells is still limited, albeit neurons are dependent on the trophic support provided by astrocytes release. Materials and Methods. The use of the McCarthy and de Vellis methods for isolating glial cells has been regarded as an essential tool for studying their function. This study aims to evaluate the effects of ethanol and deferoxamine on primary rat glial cell cultures and try to explain, as far as possible, the relevance of such effects for patients with chronic alcoholism and traumatic spinal cord injuries. Discussion. Because glial cells are very important in the functioning of the central nervous system and experiments cannot be performed on human primary nerve cell cultures, we performed an experiment on glial cells harvested from the newborn rat, analyzing the dynamics of IL-6 and TNF alpha on models of suffering in spinal cord injury (hypoxia and thermally stress). Conclusion. Inhibition of TNF alpha synthesis was more important at 7 days posttraumatic in cells with prolonged ethanolic exposure, even if protein levels of IL-6 were elevated (under similar experimental conditions). Thus, we can say that long-term exposure to ethanol of nerve cells can ensure a favorable evolution of medical recovery (by increasing TNF alpha), even if the inflammatory process remains active (shown by elevated IL-6 values). Keywords: ethyl alcohol, deferoxamine, primary glial cells cultures, traumatic Spinal Cord Injury

Construction of a Necroptosis-Related miRNA Signature for Predicting the Prognosis of Patients With Hepatocellular Carcinoma

Background: Many miRNAs have been demonstrated to be associated with the prognosis of hepatocellular carcinoma (HCC). However, how to combine necroptosis-related miRNAs to achieve the best predictive effect in estimating HCC patient survival has not been explored.

Methods: The mRNA and miRNA expression profile were downloaded from a public database (TCGA-LIHC cohort). Necroptosis-related genes were obtained from previous references, and necroptosis-related miRNAs were identified using Pearson analysis. Subsequently, differential expression miRNAs (DEms) were identified in HCC and paracancer normal samples based on necroptosis-related miRNA expression. The whole set with HCC was randomized into a training set and testing set (1:1). LASSO-Cox regression analysis was used to construct an miRNA signature. Multiple statistical methods were used to validate the clinical benefit of signature in HCC patients, including receiver operator characteristic (ROC) curves, Kaplan–Meier survival analyses, and decision curve analysis (DCA). The downstream target genes of miRNAs were obtained from different online tools, and the potential pathways involved in miRNAs were explored. Finally, we conducted RT-qPCR in SK-HEP-1, THLE-3, and HUH-7 cell lines for miRNAs involved in the signature.

Results: The results showed that a total of eight specific necroptosis-related miRNAs were screened between HCC and adjacent tissues in the training set. Subsequently, based on the aforementioned miRNAs, 5-miRNA signature (miR-139-5p, hsa-miR-326, miR-10b-5p, miR-500a-3p, and miR-592) was generated by LASSO-Cox regression analysis. Multivariate Cox regression analysis showed that the risk scores were independent prognostic indicators in each set. The area under curves (AUCs) of 1 year, 3 years, 5 years, and 7 years were high in each set (AUC >0.7). DCA analysis also revealed that the risk score had a potential benefit than other clinical characteristics. Meanwhile, survival analysis showed that the high-risk group showed low survival probabilities. Moreover, the results of enrichment analysis showed that specific miRNAs were mainly enriched in the cAMP signaling pathway and TNF signaling pathway. Finally, the results of RT-qPCR were consistent with the prediction results in public databases.

Conclusion: Our study establishes a robust tool based on 5-necroptosis-related miRNAs for the prognostic management of HCC patients.

Tanshinone IIA: New Perspective on the Anti-Tumor Mechanism of A Traditional Natural Medicine

The search for natural and efficacious antineoplastic drugs, with minimal toxicity and side effects, is an important part of antitumor drug research and development. Tanshinone IIA is the most evaluated lipophilic active component of Salvia miltiorrhiza. Tanshinone IIA is a path-breaking traditional drug applied in cardiovascular treatment. It has also been found that tanshinone IIA plays an important role in the digestive, respiratory and circulatory systems, as well as in other tumor diseases. Tanshinone IIA significantly inhibits the proliferation of several types of tumors, blocks the cell cycle, induces apoptosis and autophagic death, in addition to inhibiting cell migration and invasion. Among these, the regulation of tumor-cell apoptosis signaling pathways is the key breakthrough point in several modes of antitumor therapy. The PI3K/AKT/MTOR signaling pathway and the JNK pathway are the key pathways for tanshinone IIA to induce tumor cell apoptosis. In addition to glycolysis, reactive oxygen species and signal transduction all play an active role with the participation of tanshinone IIA. Endogenous apoptosis is considered the main mechanism of tumor apoptosis induced by tanshinone IIA. Multiple pathways and targets play a role in the process of endogenous apoptosis. Tanshinone IIA can protect chemotherapy drugs, which is mainly reflected in the protection of the side effects of chemotherapy drugs, such as neurotoxicity and inhibition of the hematopoietic system. Tanshinone IIA also has a certain regulatory effect on tumor angiogenesis, which is mainly manifested in the control of hypoxia. Our findings indicated that tanshinone IIA is an effective treatment agent in the cardiovascular field and plays a significant role in antitumor therapeutics. This paper reviews the pharmacological potential and inhibitory effect of tanshinone IIA on cancer. It is greatly anticipated that tanshinone IIA will be employed as an adjuvant in the treatment of various cancers.

Dehydroevodiamine inhibits lung metastasis by suppressing survival and metastatic abilities of colorectal cancer cells

BACKGROUND

Despite the rising 5-year survival rate of colorectal cancer (CRC) patients, the survival rate decreases as the stage progress, and a low survival rate is highly associated with metastasis.

PURPOSE

The purpose of our study is to investigate the effect of dehydroevodiamine (DHE) on the lung metastasis of CRC and the proliferation of CRC cells.

STUDY DESIGN

Cell death was confirmed after DHE treatment on several CRC cell lines. The mechanism of cell cytotoxicity was found using flow cytometry. After that, the expression of the proteins or mRNAs related to the cell cytotoxicity was confirmed. Also, anti-metastatic ability of DHE in CRC cells was measured by checking the expression of Epithelial to Mesenchymal Transition (EMT) markers. Lung metastasis mouse model was established, and DHE was administered orally for 14 days.

RESULTS

DHE suppressed the viability of HCT116, CT26, SW480, and LoVo cells. DHE treatment led to G2/M arrest via a reduction of cyclin B1/CDK1 and caspase-dependent apoptosis. It also induced autophagy by regulating LC3-II and beclin-1 expression. Additionally, migration and invasion of CRC cells were decreased by DHE through regulation of the expression of EMT markers. Oral administration of DHE could inhibit the lung metastasis of CT26 cells in an in vivo model.

CONCLUSION

Our study demonstrated that DHE has a potential therapeutic effect on colorectal cancer metastasis.

The role of FUNDC1 in mitophagy, mitochondrial dynamics and human diseases

Mitochondria are the principal sites of energy metabolism and provide most of the energy needed for normal cellular function. They are dynamic organelles that constantly undergo fission, fusion and mitophagy to maintain their homeostasis and function. However, dysregulated mitochondrial dynamics and mitophagy leads to reduced ATP generation and mutation of their DNA, which ultimately leads to cell death. Increasing evidence has shown that the FUN14 domain-containing protein 1 (FUNDC1), a novel mitophagy receptor, participates in the process of mitochondrial dynamics and mitophagy and plays a critical role in various human diseases. Herein, we review the role of FUNDC1 in mitophagy and mitochondrial dynamics, thus providing a better understanding of the relationship between the two processes. Moreover, we summarize the treatments targeting FUNDC1, and suggest that FUNDC1 may represent a promising therapeutic target for the treatment of several human diseases such as cardiovascular diseases, metabolic syndrome, cancer and chronic obstructive pulmonary disease (COPD).

Ultrasound-targeted nucleic acid delivery for solid tumor therapy

Depending upon multiple factors, malignant solid tumors are conventionally treated by some combination of surgical resection, radiation, chemotherapy, and immunotherapy. Despite decades of research, therapeutic responses remain poor for many cancer indications. Further, many current therapies in our armamentarium are either invasive or accompanied by toxic side effects. In lieu of traditional pharmaceutics and invasive therapeutic interventions, gene therapies offer more flexible and potentially more durable approaches for new anti-cancer therapies. Nonetheless, many current gene delivery approaches suffer from low transfection efficiency due to physiological barriers limiting extravasation and uptake of genetic material. Additionally, systemically administered gene therapies may lack target-specificity, which can lead to off-target effects. To overcome these challenges, many preclinical studies have shown the utility of focused ultrasound (FUS) to increase macromolecule uptake in cells and tissue under image guidance, demonstrating promise for improved delivery of therapeutics to solid tumors. As FUS-based drug delivery is now being tested in several clinical trials around the world, FUS-targeted gene therapy for solid tumor therapy may not be far behind. In this review, we comprehensively cover the literature pertaining to preclinical attempts to more efficiently deliver therapeutic genetic material with FUS and offer perspectives for future studies and clinical translation.

Cancer molecular biology and strategies for the design of cytotoxic gold(I) and gold(III) complexes: a tutorial review

This tutorial review highlights key principles underpinning the design of selected metallodrugs to target specific biological macromolecules (DNA and proteins). The review commences with a descriptive overview of the eukaryotic cell cycle and the molecular biology of cancer, particularly apoptosis, which is provided as a necessary foundation for the discovery, design, and targeting of metal-based anticancer agents. Drugs which target DNA have been highlighted and clinically approved metallodrugs discussed. A brief history of the development of mainly gold-based metallodrugs is presented prior to addressing ligand systems for stabilizing and adding functionality to bio-active gold(I) and gold(III) complexes, particularly in the burgeoning field of anticancer metallodrugs. Concepts such as multi-modal and selective cytotoxic agents are covered where necessary for selected compounds. The emerging role of carbenes as the ligand system of choice to achieve these goals for gold-based metallodrug candidates is highlighted prior to closing the review with comments on some future directions that this research field might follow. The latter section ultimately emphasizes the importance of understanding the fate of metal complexes in cells to garner key mechanistic insights.

Stingless Bee Propolis: New Insights for Anticancer Drugs

Natural products are important sources of biomolecules possessing antitumor activity and can be used as anticancer drug prototypes. The rich biodiversity of tropical and subtropical regions of the world provides considerable bioprospecting potential, including the potential of propolis produced by stingless bee species. Investigations of the potential of these products are extremely important, not only for providing a scientific basis for their use as adjuvants for existing drug therapies but also as a source of new and potent anticancer drugs. In this context, this article organizes the main studies describing the anticancer potential of propolis from different species of stingless bees with an emphasis on the chemical compounds, mechanisms of action, and cell death profiles. These mechanisms include apoptotic events; modulation of BAX, BAD, BCL2-L1 (BCL-2 like 1), and BCL-2; depolarization of the mitochondrial membrane; increased caspase-3 activity; poly (ADP-ribose) polymerase (PARP) cleavage; and cell death induction by necroptosis via receptor interacting protein kinase 1 (RIPK1) activation. Additionally, the correlation between compounds with antioxidant and anti-inflammatory potential is demonstrated that help in the prevention of cancer development. In summary, we highlight the important antitumor potential of propolis from stingless bees, but further preclinical and clinical trials are needed to explore the selectivity, efficacy, and safety of propolis.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

Therapeutic potential of HIV-1 entry inhibitor peptidomimetics

Human immunodeficiency virus 1 (HIV-1) infection remains a public health concern globally. Although great strides in the management of HIV-1 have been achieved, current highly active antiretroviral therapy is limited by multidrug resistance, prolonged use-related effects, and inability to purge the HIV-1 latent pool. Even though novel therapeutic options with HIV-1 broadly neutralizing antibodies (bNAbs) are being explored, the scalability of bNAbs is limited by economic cost of production and obligatory requirement for parenteral administration. However, these limitations can be addressed by antibody mimetics/peptidomimetics of HIV-1 bNAbs. In this review we discuss the limitations of HIV-1 bNAbs as HIV-1 entry inhibitors and explore the potential therapeutic use of antibody mimetics/peptidomimetics of HIV-1 entry inhibitors as an alternative for HIV-1 bNAbs. We highlight the reduced cost of production, high specificity, and oral bioavailability of peptidomimetics compared to bNAbs to demonstrate their suitability as candidates for novel HIV-1 therapy and conclude with some perspectives on future research toward HIV-1 novel drug discovery.

Treating MCF7 breast cancer cell with proteasome inhibitor Bortezomib restores apoptotic factors and sensitizes cell to Docetaxel

Chemoresistance is the leading cause of limiting long-term treatment success in cancer cells. Anticancer drugs usually kill cells through apoptosis induction and defects in this signaling pathway lead to chemoresistance. Apoptotic protease activating factor 1 regulates cellular stress evoked by chemotherapeutic agents through facilitating apoptosome assembling but can be degraded by proteasome. This study examined the role of proteasome inhibitor Bortezomib in the cytotoxic effects of Docetaxel on MCF7 cells response and its correlation with Apaf-1 expression level. MTT assay, caspase 3/7 activity assay, propidium iodide staining, adenosine triphosphate and reactive oxygen species amount measurements were utilized to demonstrate the role of Bortezomib in Docetaxel efficacy with and without Apaf-1 overexpressing. Meanwhile, two-dimensional cell migration assay was performed by scratch wound assay. The combination of Docetaxel with Bortezomib was significantly more cytotoxic compared single drug, more effectively delayed cell growth, reduced ATP level and increased ROS production. In Apaf-1 overexpressing, Docetaxel was more efficient in preventing cell migration, however, Docetaxel plus Bortezomib were not significantly effective; and fluorescence images supported the interpretation. Our findings demonstrated MCF7 resistance to Docetaxel is due in part to low Apaf-1 level and Apaf-1 overexpression resulted in the increase of cell susceptibility to Docetaxel stimulus. We assume that proteasome inhibitor may restore apoptotic proteins like Apaf-1 and prevent the degradation of cytosolic cytochrome c released by Docetaxel, consequently triggering intrinsic apoptosis and promoting cancer cell death. Collectively, treating MCF7 breast cells with proteasome inhibitor sensitizes cells to Docetaxel-induced apoptosis and possibly overcomes chemoresistance.

Ethanol Extracts of Solanum lyratum Thunb Regulate Ovarian Cancer Cell Proliferation, Apoptosis, and Epithelial-to-Mesenchymal Transition (EMT) via the ROS-Mediated p53 Pathway

Ovarian cancer is a type of common gynecological tumors with high incidence and poor survival. The anticancer effects of the traditional Chinese medicine Solanum lyratum Thunb (SLT) have been intensively investigated in various cancers but in ovarian cancer is rare. The current study is aimed at investigating the effect of SLT on ovarian cancer cells. Lactate dehydrogenase (LDH) and MTT assays indicated that SLT concentrations of 0.25 and 0.5 μg/mL were not cytotoxic and had significant inhibitory effects on the cell viabilities of A2780 and SKOV3 cells, hence were used for subsequent experiments. Flow cytometric and western blot analysis revealed that SLT effectively suppressed ovarian cancer cell proliferation via inducing cell cycle arrest and increasing apoptosis. Cell cycle and apoptosis-related protein expressions were also regulated in SLT-treated cells. Moreover, DCFH-DA and western blot assays demonstrated that SLT enhanced ROS accumulation and subsequently activated the p53 signaling pathway. However, SLT-regulated ovarian cancer cell proliferation, apoptosis, migration, invasion, and EMT were significantly reversed by an ROS inhibitor (NAC, N-acetyl-L-cysteine). Furthermore, A2780 and SKOV3 cells cocultured with M0 macrophages showed that SLT activated the polarization of M0 macrophages to M1 macrophages and inhibited the polarization to M2 macrophages, with the increased percentage of CD86+ cells and decreased percentage of CD206+ cells were detected. In summary, this study illustrated the anticancer effects of SLT on ovarian cancer cells, suggesting that SLT may have the potential to provide basic evidence for the discovery of antiovarian cancer agents.

Death agonist antibody against TRAILR2/DR5/TNFRSF10B enhances birinapant anti-tumor activity in HPV-positive head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) induced by human papillomavirus (HPV) have increased recently in the US. However, the distinct alterations of molecules involved in the death pathways and drug effects targeting inhibitor of apoptosis proteins (IAPs) have not been extensively characterized in HPV(+) HNSCC cells. In this study, we observed the distinct genomic and expression alterations of nine genes involved in cell death in 55% HNSCC tissues, which were associated with HPV status, tumor staging, and anatomic locations. Expression of four genes was statistically correlated with copy number variation. A panel of HPV(+) HNSCC lines showed abundant TRAILR2 and IAP1 protein expression, but were not sensitive to IAP inhibitor birinapant alone, while combinatory treatment with TNFα or especially TRAIL enhanced this drug sensitivity. The death agonistic TRAILR2 antibody alone showed no cell inhibitory effects, whereas its combination with birinapant and/or TRAIL protein demonstrated additive or synergistic effects. We observed predominantly late apoptosis mode of cell death after combinatorial treatments, and pan-caspase (ZVAD) and caspase-8 (ZIETD) inhibitors attenuated treatment-induced cell death. Our genomic and expression data-driven study provides a framework for identifying relevant combinatorial therapies targeting death pathways in HPV(+) HNSCC and other squamous cancer types.

A novel and distinctive mode of cell death revealed by using non-thermal atmospheric pressure plasma: The involvements of reactive oxygen species and the translation inhibitor Pdcd4

Cells death is indispensable for embryonic development, tissue homeostasis, and the elimination of cancer, virally infected, or degenerated cells in multicellular organisms. It occurs not only via existing modes but also via unidentified modes, whose elucidation requires. Exposure to non-thermal atmospheric pressure plasma (NTAPP) has been demonstrated to induce cell death, probably because of its ability to generate reactive oxygen species (ROS). However, the mode of this cell death and its underlying mechanism remained elusive. Here we show cell death occurring in a novel and distinctive mode different from apoptosis and necrosis/necroptosis through a mechanism that ROS mediate the loss of the translation inhibitor Programmed cell death 4 (Pdcd4) when cells are cultured in solutions activated by NTAPP irradiation. Thus, our study performed with NTAPP-activated solutions may provide insight into the existence of the atypical cell death in cells and some features of its distinguishing mode and underlying mechanism.

Inhibiting protein phosphatase 2A increases the antitumor effect of protein arginine methyltransferase 5 inhibition in models of glioblastoma

BACKGROUND

Despite multi-model therapy of maximal surgical resection, radiation, chemotherapy, and tumor treating fields, the median survival of Glioblastoma (GBM) patients is less than 15 months. Protein Arginine Methyltransferase 5 (PRMT5) catalyzes the symmetric di-methylation of arginine residues and is overexpressed in GBM. Inhibition of PRMT5 causes senescence in stem-like GBM tumor cells. LB100, a first-in-class small molecular inhibitor of Protein Phosphatase 2A (PP2A) can sensitize therapy-resistant tumor cells. Here, we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition.

METHODS

Patient-derived primary GBM neurospheres (GBMNS), transfected with PRMT5 target-specific siRNA were treated with LB100 and subjected to in vitro assays including PP2A activity and western blot. The intracranial mouse xenograft model was used to test the in vivo antitumor efficacy of combination treatment.

RESULTS

We found that PRMT5-depletion increased PP2A activity in GBMNS. LB100 treatment significantly reduced the viability of PRMT5-depleted GBMNS compared to PRMT5 intact GBMNS. LB100 enhanced G1 cell cycle arrest induced by PRMT5-depletion. Combination therapy also increased the expression of phospho-MLKL. Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100, indicating that necroptosis caused the enhanced cytotoxicity of combination therapy. In the in vivo mouse tumor xenograft model, LB100 treatment combined with transient depletion of PRMT5 significantly decreased tumor size and prolonged survival, while LB100 treatment alone had no survival benefit.

CONCLUSION

Overall, combined PRMT5 and PP2A inhibition had significantly greater antitumor effects than PRMT5 inhibition alone.

Protective effect of rapamycin against acrylamide-induced hepatotoxicity: The associations between autophagy, apoptosis, and necroptosis

Acrylamide (ACRL) was demonstrated to induce hepatotoxicity and programmed cell death (PCD). Rapamycin (RAPA)-induced autophagy had been reported to limit the progression of hepatocellular injury in experimental models. This research was designed to study two death pathways involved in ACRL-induced hepatotoxicity and the modulating effect of RAPA on the resulting hepatic injury. Thirty-six adult male rats were divided into three groups: control group, ACRL-treated group (20 mg kg/day), and the last group co-treated with ACRL plus RAPA (0.5 mg kg/day). Drugs were administered for 21 days via oral gavage. Blood samples were collected to assess alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Livers were dissected; parts were used for detection of superoxide dismutase (SOD) and malondialdehyde (MDA) tissue levels. Other parts were processed for hematoxylin and eosin, Masson's trichrome staining, immunostaining for microtubule-associated proteins 1A/1B light chain 3B (LC3), ubiquitin-binding protein (p62), caspase-3, and receptor-interacting protein kinase 1 (RIPK1). ACRL induced a significant elevation in ALT, AST, MDA levels, and reduction in the SOD level. ACRL also induced hepatocellular injury, fibrosis, and defective autophagy indicated by elevation of LC3 and p62 and increased p62/LC3 ratio. Moreover, it increased the apoptotic (caspase-3) and necroptotic (RIPK1) markers expression. RAPA significantly reduced liver enzymes, oxidative stress, fibrosis, and improved liver histology. Moreover, RAPA decreased p62/LC3 ratio indicated enhanced autophagy, and significantly reduced caspase-3 and RIPK1 expression. In conclusion, RAPA maintained autophagic activity which may save the hepatocytes from PCD and enhance cell viability.

A doxorubicin-platinum conjugate system: impacts on PI3K/AKT actuation and apoptosis in breast cancer cells

In recent years, the development of a nano-conjugate system for drug delivery applications has gained attention among researchers. Keeping this in mind, in this study, we developed a doxorubicin-platinum conjugate system that targeted breast cancer cell lines. To achieve this, we developed platinum nanoparticles using polyvinylpyrrolidone (PVP). High resolution-transmission electron microscopy (HR-TEM) revealed the occurrence of octopod-shaped platinum nanoparticles. Subsequently, doxorubicin (DOX) was conjugated on the surface of the as-prepared platinum octopods via an in situ stirring method. The physicochemical characterization of the doxorubicin-platinum conjugate system revealed that the PVP of PtNPs interacts with the NH2 group of doxorubicin via electrostatic interaction/hydrogen bonding. Besides, the doxorubicin-platinum conjugate system exhibited a sustained drug release profile within the cancer cells. Furthermore, the evaluation of the in vitro anticancer efficacy of the doxorubicin-platinum conjugate system in breast cancer cells (MCF-7 and MDA-MB-231) unveiled the induction of apoptosis via intracellular ROS and DNA damage, rather than free DOX and PtNPs. Remarkably, we also perceived that the doxorubicin-platinum conjugate system was strong enough to down-regulate the PI3K/AKT signalling pathway. As a result, the tumour suppressor gene PTEN was activated, which led to the stimulation of a mitochondrion-based intrinsic apoptotic pathway and its downstream caspases, triggering cell death. Hence, our findings suggested that a biologically stable doxorubicin-platinum conjugate system could be an imperative therapeutic agent for anticancer therapy in the near future.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

Autophagy Takes Center Stage as a Possible Cancer Hallmark

Cancer remains one of the leading causes of death worldwide, despite significant advances in cancer research and improvements in anticancer therapies. One of the major obstacles to curing cancer is the difficulty of achieving the complete annihilation of resistant cancer cells. The resistance of cancer cells may not only be due to intrinsic factors or factors acquired during the evolution of the tumor but may also be caused by chemotherapeutic treatment failure. Conversely, autophagy is a conserved cellular process in which intracellular components, such as damaged organelles, aggregated or misfolded proteins and macromolecules, are degraded or recycled to maintain cellular homeostasis. Importantly, autophagy is an essential mechanism that plays a key role in tumor initiation and progression. Depending on the cellular context and microenvironmental conditions, autophagy acts as a double-edged sword, playing a role in inducing apoptosis or promoting cell survival. In this review, we propose several scenarios in which autophagy could contribute to cell survival or cell death. Moreover, a special focus on novel promising targets and therapeutic strategies based on autophagic resistant cells is presented.

High Levels of miR-7-5p Potentiate Crizotinib-Induced Cytokilling and Autophagic Flux by Targeting RAF1 in NPM-ALK Positive Lymphoma Cells

Simple Summary

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas are a pediatric disease, which still needs treatment improvement. Crizotinib was the first ALK-targeted inhibitor used in clinics, but relapses are now known to occur. Current research efforts indicate that combined therapies could represent a superior strategy to eradicate malignant cells and prevent tumor recurrence. Autophagy is a self-digestion cellular process, known to be induced upon diverse cancer therapies. Our present work demonstrates that the potentiation of the crizotinib-induced autophagy flux, through the serine/threonine kinase RAF1 downregulation, drives ALK+ ALCL cells to death. These results should encourage further investigations on the therapeutic modulation of autophagy in this particular cancer settings and other ALK-related malignancies.

Abstract

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas (ALK+ ALCL) are an aggressive pediatric disease. The therapeutic options comprise chemotherapy, which is efficient in approximately 70% of patients, and targeted therapies, such as crizotinib (an ALK tyrosine kinase inhibitor (TKI)), used in refractory/relapsed cases. Research efforts have also converged toward the development of combined therapies to improve treatment. In this context, we studied whether autophagy could be modulated to improve crizotinib therapy. Autophagy is a vesicular recycling pathway, known to be associated with either cell survival or cell death depending on the cancer and therapy. We previously demonstrated that crizotinib induced cytoprotective autophagy in ALK+ lymphoma cells and that its further intensification was associated with cell death. In line with these results, we show here that combined ALK and Rapidly Accelerated Fibrosarcoma 1 (RAF1) inhibition, using pharmacological (vemurafenib) or molecular (small interfering RNA targeting RAF1 (siRAF1) or microRNA-7-5p (miR-7-5p) mimics) strategies, also triggered autophagy and potentiated the toxicity of TKI. Mechanistically, we found that this combined therapy resulted in the decrease of the inhibitory phosphorylation on Unc-51-like kinase-1 (ULK1) (a key protein in autophagy initiation), which may account for the enforced autophagy and cytokilling effect. Altogether, our results support the development of ALK and RAF1 combined inhibition as a new therapeutic approach in ALK+ ALCL.

Cheadle E, M. Illidge T. Understanding the Effects of Radiotherapy on the Tumour Immune Microenvironment to Identify Potential Prognostic and Predictive Biomarkers of Radiotherapy Response

Radiotherapy (RT) is a highly effective anti-cancer treatment. Immunotherapy using immune checkpoint blockade (ICI) has emerged as a new and robust pillar in cancer therapy; however, the response rate to single agent ICI is low whilst toxicity remains. Radiotherapy has been shown to have local and systemic immunomodulatory effects. Therefore, combining RT and immunotherapy is a rational approach to enhance anti-tumour immune responses. However, the immunomodulatory effects of RT can be both immunostimulatory or immunosuppressive and may be different across different tumour types and patients. Therefore, there is an urgent medical need to establish biomarkers to guide clinical decision making in predicting responses or in patient selection for RT-based combination treatments. In this review, we summarize the immunological effects of RT on the tumour microenvironment and emerging biomarkers to help better understand the implications of these immunological changes, and we provide new insights into the potential for combination therapies with RT and immunotherapy.

Docosahexaenoic acid protection against palmitic acid-induced lipotoxicity in NGF-differentiated PC12 cells involves enhancement of autophagy and inhibition of apoptosis and necroptosis

Lipotoxicity (LTx) leads to cellular dysfunction and cell death and has been proposed to be an underlying process during traumatic and hypoxic injuries and neurodegenerative conditions in the nervous system. This study examines cellular mechanisms responsible for docosahexaenoic acid (DHA 22:6 n‐3) protection in nerve growth factor‐differentiated pheochromocytoma (NGFDPC12) cells from palmitic acid (PAM)‐mediated lipotoxicity (PAM‐LTx). NGFDPC12 cells exposed to PAM show a significant lipotoxicity demonstrated by a robust loss of cell viability, apoptosis, and increased HIF‐1α and BCL2/adenovirus E1B 19 kDa protein‐interacting protein 3 gene expression. Treatment of NGFDPC12 cells undergoing PAM‐LTx with the pan‐caspase inhibitor ZVAD did not protect, but shifted the process from apoptosis to necroptosis. This shift in cell death mechanism was evident by the appearance of the signature necroptotic Topo I protein cleavage fragments, phosphorylation of mixed lineage kinase domain‐like, and inhibition with necrostatin‐1. Cultures exposed to PAM and co‐treated with necrostatin‐1 (necroptosis inhibitor) and rapamycin (autophagy promoter), showed a significant protection against PAM‐LTx compared to necrostatin‐1 alone. In addition, co‐treatment with DHA, as well as 20:5 n‐3, 20:4 n‐6, and 22:5 n‐3, in the presence of PAM protected NGFDPC12 cells against LTx. DHA‐induced neuroprotection includes restoring normal levels of HIF‐1α and BCL2/adenovirus E1B 19 kDa protein‐interacting protein 3 transcripts and caspase 8 and caspase 3 activity, phosphorylation of beclin‐1, de‐phosphorylation of mixed lineage kinase domain‐like, increase in LC3‐II, and up‐regulation of Atg7 and Atg12 genes, suggesting activation of autophagy and inhibition of necroptosis. Furthermore, DHA‐induced protection was suppressed by the lysosomotropic agent chloroquine, an inhibitor of autophagy. We conclude that DHA elicits neuroprotection by regulating multiple cell death pathways including enhancement of autophagy and inhibiting apoptosis and necroptosis.

SpBOK inhibits WSSV infection by regulating the apoptotic pathway in mud crab (Scylla paramamosain)

B-cell lymphoma 2 (Bcl-2) related ovarian killer (BOK) is a member of the Bcl-2 family, which has a similar function to BAX and BAK in the process of apoptosis. However, how BOK activates the intrinsic (mitochondrial) apoptotic pathway remains poorly understood in invertebrates. In this study, SpBOK identified in mud crab is an important effector responsible for the anti-WSSV (White Spot Syndrome Virus) infection by activating the apoptotic pathway. The SpBOK gene encoded a 282 amino acid peptides (molecular mass of 29 kD), which contained four distinct Bcl-2 family homology (BH) domains. SpBOK was widely expressed in all tested tissues and up-regulated after WSSV infection in vivo. The role of SpBOK on the anti-WSSV response in mud crab was investigated by using the RNAi approach in vivo. SpBOK exerted a regulatory role in changing the mitochondrial membrane potential (⊿ψm) and activating the caspase signaling and thus induced apoptosis. Moreover, the results showed that WSSV replication in mud crab could be effectively inhibited by SpBOK. Therefore, the results of this study demonstrated that SpBOK can inhibit WSSV infection by regulating the intrinsic apoptosis pathway in mud crab.

Measurement and models accounting for cell death capture hidden variation in compound response

Cancer cell sensitivity or resistance is almost universally quantified through a direct or surrogate measure of cell number. However, compound responses can occur through many distinct phenotypic outcomes, including changes in cell growth, apoptosis, and non-apoptotic cell death. These outcomes have divergent effects on the tumor microenvironment, immune response, and resistance mechanisms. Here, we show that quantifying cell viability alone is insufficient to distinguish between these compound responses. Using an alternative assay and drug-response analysis amenable to high-throughput measurement, we find that compounds with identical viability outcomes can have very different effects on cell growth and death. Moreover, additive compound pairs with distinct growth/death effects can appear synergistic when only assessed by viability. Overall, these results demonstrate an approach to incorporating measurements of cell death when characterizing a pharmacologic response.

Tetrahydrobenzimidazole TMQ0153 triggers apoptosis, autophagy and necroptosis crosstalk in chronic myeloid leukemia

By comparing imatinib-sensitive and -resistant chronic myeloid leukemia (CML) cell models, we investigated the molecular mechanisms by which tetrahydrobenzimidazole derivative TMQ0153 triggered caspase-dependent apoptosis at low concentrations accompanied by loss of mitochondrial membrane potential (MMP) and increase of cytosolic free Ca²⁺ levels. Interestingly, at higher concentrations, TMQ0153 induced necroptotic cell death with accumulation of ROS, both preventable by N-acetyl-L-cysteine (NAC) pretreatment. At necroptosis-inducing concentrations, we observed increased ROS and decreased ATP and GSH levels, concomitant with protective autophagy induction. Inhibitors such as bafilomycin A1 (baf-A1) and siRNA against beclin 1 abrogated autophagy, sensitized CML cells against TMQ0153 and enhanced necroptotic cell death. Importantly, TMQ153-induced necrosis led to cell surface exposure of calreticulin (CRT) and ERp57 as well as the release of extracellular ATP and high mobility group box (HMGB1) demonstrating the capacity of this compound to release immunogenic cell death (ICD) markers. We validated the anti-cancer potential of TMQ0153 by in vivo inhibition of K562 microtumor formation in zebrafish. Taken together, our findings provide evidence that cellular stress and redox modulation by TMQ0153 concentration-dependently leads to different cell death modalities including controlled necrosis in CML cell models.