A Small Molecule Stabilizer of the MYC G4-Quadruplex Induces Endoplasmic Reticulum Stress, Senescence and Pyroptosis in Multiple Myeloma

Non-coding RNAs as key regulators of Gasdermin-D mediated pyroptosis in cancer therapy

Pyroptosis is an inflammatory programed cell death process that plays a crucial role in cancer therapeutic, while Gasdermin-D is a critical effector protein for pyroptosis execution. This review discusses the intricate interactions between Gasdermin-D and some non-coding RNAs (lncRNA, miRNA, siRNA) and their potential application in the regulation of pyroptosis as an anticancer therapy. Correspondingly, these ncRNAs significantly implicate in Gasdermin-D expression and function regarding the pyroptosis pathway. Functioning as competing endogenous RNAs (ceRNAs), these ncRNAs might regulate Gasdermin-D at the molecular level, underlying fatal cell death caused by cancer and tumor propagation. Therefore, these interactions appeal to therapeutics, offering new avenues for cancer treatment. It address this research gap by discussing the possible roles of ncRNAs as mediators of gasdermin-D regulation. It suggest therapeutic strategies based on the current research findings to ensure the interchange between the ideal pyroptosis and cancer cell death.

Therapeutic strategies of targeting non-apoptotic regulated cell death (RCD) with small-molecule compounds in cancer

Regulated cell death (RCD) is a controlled form of cell death orchestrated by one or more cascading signaling pathways, making it amenable to pharmacological intervention. RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis, facilitating development, and modulating immunity. Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival. Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse, comparable to apoptosis. Moreover, they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs. With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines, a growing number of small-molecule compounds targeting single or multiple pathways have been discovered, providing novel strategies for current cancer therapy. In this review, we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines, mainly including autophagy-dependent cell death, ferroptosis, cuproptosis, disulfidptosis, necroptosis, pyroptosis, alkaliptosis, oxeiptosis, parthanatos, mitochondrial permeability transition (MPT)-driven necrosis, entotic cell death, NETotic cell death, lysosome-dependent cell death, and immunogenic cell death (ICD). Furthermore, we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds. In brief, these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines, ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

G-quadruplex-guided cisplatin triggers multiple pathways in targeted chemotherapy and immunotherapy

G-quadruplexes (G4s) are atypical nucleic acid structures involved in basic human biological processes and are regulated by small molecules. To date, pyridostatin and its derivatives [e.g., PyPDS (4-(2-aminoethoxy)-N 2,N 6-bis(4-(2-(pyrrolidin-1-yl) ethoxy) quinolin-2-yl) pyridine-2,6-dicarboxamide)] are the most widely used G4-binding small molecules and considered to have the best G4 specificity, which provides a new option for the development of cisplatin-binding DNA. By combining PyPDS with cisplatin and its analogs, we synthesize three platinum complexes, named PyPDSplatins. We found that cisplatin with PyPDS (CP) exhibits stronger specificity for covalent binding to G4 domains even in the presence of large amounts of dsDNA compared with PyPDS either extracellularly or intracellularly. Multiomics analysis reveals that CP can effectively regulate G4 functions, directly damage G4 structures, activate multiple antitumor signaling pathways, including the typical cGAS-STING pathway and AIM2-ASC pathway, trigger a strong immune response and lead to potent antitumor effects. These findings reflect that cisplatin-conjugated specific G4 targeting groups have antitumor mechanisms different from those of classic cisplatin and provide new strategies for the antitumor immunity of metals.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Reniformin A suppresses non-small cell lung cancer progression by inducing TLR4/NLRP3/caspase-1/GSDMD-dependent pyroptosis

Pyroptosis is an inflammatory form of programmed cell death that plays an important role in regulating tumor progression. Reniformin A (RA) is a natural compound isolated from the medicinal herb Isodon excisoides that has been applied as folk medicine in the treatment of esophageal cancer. However, whether RA has an individual function in cancer and the molecular mechanisms remain unclear. Here, we show that in non-small-cell lung cancer (NSCLC), RA inhibits tumor growth by functioning as a pyroptosis inducer to promote TLR4/NLRP3/caspase-1/GSDMD axis. Specially, RA treatment increased Toll-like receptor 4 (TLR4) protein expression level by enhancing the TLR4 stability. Based on the molecular docking, we identified that RA directly bound to TLR4 to activate the NLRP3 inflammasome and promote pyroptosis in A549 cells. Moreover, TLR4 is essential for RA-induced pyroptosis, and loss of TLR4 abolished RA-induced pyroptosis and further reduced the inhibitory effect of RA on NSCLC. In vivo experiments confirmed that RA inhibited the growth of lung tumors in mice by affecting pyroptosis in a dose-dependent manner. Furthermore, TLR4 knockdown abolished RA-induced pyroptosis and inhibited the effect of RA chemotherapy in vivo. In conclusion, we propose that RA has a significant anticancer effect in NSCLC by inducing TLR4/NLRP3/caspase-1/GSDMD-mediated pyroptosis, which may provide a potential strategy for the treatment of NSCLC.

MYC Oncogene: A Druggable Target for Treating Cancers with Natural Products

Various diseases, including cancers, age-associated disorders, and acute liver failure, have been linked to the oncogene, MYC. Animal testing and clinical trials have shown that sustained tumor volume reduction can be achieved when MYC is inactivated, and different combinations of therapeutic agents including MYC inhibitors are currently being developed. In this review, we first provide a summary of the multiple biological functions of the MYC oncoprotein in cancer treatment, highlighting that the equilibrium points of the MYC/MAX, MIZ1/MYC/MAX, and MAD (MNT)/MAX complexes have further potential in cancer treatment that could be used to restrain MYC oncogene expression and its functions in tumorigenesis. We also discuss the multifunctional capacity of MYC in various cellular cancer processes, including its influences on immune response, metabolism, cell cycle, apoptosis, autophagy, pyroptosis, metastasis, angiogenesis, multidrug resistance, and intestinal flora. Moreover, we summarize the MYC therapy patent landscape and emphasize the potential of MYC as a druggable target, using herbal medicine modulators. Finally, we describe pending challenges and future perspectives in biomedical research, involving the development of therapeutic approaches to modulate MYC or its targeted genes. Patients with cancers driven by MYC signaling may benefit from therapies targeting these pathways, which could delay cancerous growth and recover antitumor immune responses.

The implication of pyroptosis in cancer immunology: Current advances and prospects

Pyroptosis is a regulated cell death pathway involved in numerous human diseases, especially malignant tumors. Recent studies have identified multiple pyroptosis-associated signaling molecules, like caspases, gasdermin family and inflammasomes. In addition, increasing in vitro and in vivo studies have shown the significant linkage between pyroptosis and immune regulation of cancers. Pyroptosis-associated biomarkers regulate the infiltration of tumor immune cells, such as CD4+ and CD8+ T cells, thus strengthening the sensitivity to therapeutic strategies. In this review, we explained the relationship between pyroptosis and cancer immunology and focused on the significance of pyroptosis in immune regulation. We also proposed the future application of pyroptosis-associated biomarkers in basic research and clinical practices to address malignant behaviors. Exploration of the underlying mechanisms and biological functions of pyroptosis is critical for immune response and cancer immunotherapy.

Research Progress on Pyroptosis in Hematological Malignancies

OPINION STATEMENT

Pyroptosis is a kind of programmed cell death dependent on the caspase pathway that is different from apoptosis and necrosis. Recent studies have shown that pyroptosis can be involved in the pathological processes of many diseases, such as cancers, atherosclerosis, diabetic nephropathy, and blood diseases. However, the specific mechanisms by which pyroptosis participates in the occurrence and development of hematological malignant tumors still need further exploration. This article reviews the characteristics of pyroptosis and the regulatory mechanisms promoting or inhibiting pyroptosis and discusses the role of pyroptosis in hematological malignant tumors, which could provide ideas for the clinical treatment of such tumors in the future.

Novel c-Myc G4 stabilizer EP12 promotes myeloma cytotoxicity by disturbing NF-κB signaling

Multiple myeloma (MM) is a B-cell malignancy characterized by the excessive proliferation of bone marrow plasma cells and the production of abnormal immunoglobulins. Despite advances in therapeutic strategies, it remains an incurable disease. Recently, innovative anticancer drugs have been developed and approved, leading to improvements in MM therapy; however, drug resistance continues to be a major obstacle that results in treatment failure. Therefore, the development of novel agents is imperative to achieve superior therapeutic outcomes for relapsed/refractory multiple myeloma (MM) patients. Previously, we identified EP12 as a c-Myc G4 stabilizer that could induce cytotoxicity in MM cells in vitro. However, further investigation is required to elucidate the underlying molecular mechanisms and anti-MM activity of EP12 in vivo. In this study, we have discovered that the compound EP12 effectively inhibits primary myeloma growth in vivo by destabilizing c-Myc and disrupting the canonical nuclear factor-κB (NF-κB) signaling pathway. Overall, our findings suggest that EP12, as a potent c-Myc inhibitor, holds great promise as a therapeutic agent for MM.

Identification of canonical pyroptosis-related genes, associated regulation axis, and related traditional Chinese medicine in spinal cord injury

Neuroinflammation plays an important role in spinal cord injury (SCI), and pyroptosis is inflammatory-related programmed cell death. Although neuroinflammation induced by pyroptosis has been reported in SCI, there is a lack of systematic research on SCI pyroptosis and its regulation mechanism. The purpose of this study was to systematically analyze the expression of pyroptosis-related genes (PRGs) in different SCI models and associated regulation axis by bioinformatics methods. We downloaded raw counts data of seven high-throughput sequencings and two microarray datasets from the GEO database, classified by species (rat and mouse) and SCI modes (moderate contusive model, aneurysm clip impact-compression model, and hemisection model), including mRNAs, miRNAs, lncRNAs, and circRNAs, basically covering the acute, subacute and chronic stages of SCI. We performed differential analysis by R (DEseq2) or GEO2R and found that the AIM2/NLRC4/NLRP3 inflammasome-related genes, GSDMD, IL1B, and IL18, were highly expressed in SCI. Based on the canonical NLRP3 inflammasome-mediated pyroptosis-related genes (NLRP3/PRGs), we constructed transcription factors (TFs)-NLRP3/PRGs, miRNAs- Nlrp3/PRGs and lncRNAs/circRNAs/mRNAs-miRNA- Nlrp3/PRGs (ceRNA) networks. In addition, we also predicted Traditional Chinese medicine (TCM) and small, drug-like molecules with NLRP3/PRGs as potential targets. Finally, 39 up-regulated TFs were identified, which may regulate at least two of NLRP3/PRGs. A total of 7 down-regulated miRNAs were identified which could regulate Nlrp3/PRGs. ceRNA networks were constructed including 23 lncRNAs, 3 cicrRNAs, 6 mRNAs, and 44 miRNAs. A total of 24 herbs were identified which may with two NLRP3/PRGs as potential targets. It is expected to provide new ideas and therapeutic targets for the treatment of SCI.

G-Quadruplexes in c-MYC Promoter as Targets for Cancer Therapy

Cancer is a societal burden demanding innovative approaches. A major problem with the conventional chemotherapeutic agents is their strong toxicity and other side effects due to their poor selectivity. Uncontrolled proliferation of cancer cells is due to mutations, deletions, or amplifications in genes (oncogenes) encoding for proteins that regulate cell growth and division, such as transcription factors, for example, c-MYC. The direct targeting of the c-MYC protein has been attempted but so far unsuccessfully, as it lacks a definite binding site for the modulators. Meanwhile, another approach has been explored since the discovery that G-quadruplex secondary DNA structures formed in the guanine-rich sequences of the c-MYC promoter region can downregulate the transcription of this oncogene. Here, we will overview the major achievements made in the last decades towards the discovery of a new class of anticancer drugs targeting G-quadruplexes in the c-MYC promoter of cancer cells.

Photoactivatable senolysis with single-cell resolution delays aging

Strategies that can selectively eliminate senescent cells (SnCs), namely senolytics, have been shown to promote healthy lifespan. However, it is challenging to achieve precise, broad-spectrum and tractable senolysis. Here, we integrate multiple technologies that combine the enzyme substrate of senescence-associated β-galactosidase (SA-β-gal) with fluorescence tag for the precise tracking of SnCs, construction of a bioorthogonal receptor triggered by SA-β-gal to target and anchor SnCs with single-cell resolution and incorporation of a selenium atom to generate singlet oxygen and achieve precise senolysis through controllable photodynamic therapy (PDT). We generate KSL0608-Se, a photosensitive senolytic prodrug, which is selectively activated by SA-β-gal. In naturally-aged mice, KSL0608-Se-mediated PDT prevented upregulation of age-related SnCs markers and senescence-associated secretory phenotype factors. This treatment also countered age-induced losses in liver and renal function and inhibited the age-associated physical dysfunction in mice. We therefore provide a strategy to monitor and selectively eliminate SnCs to regulate aging.

A novel prognostic model based on pyroptosis-related genes for multiple myeloma

BACKGROUND

Multiple myeloma (MM) is an incurable and relapse-prone disease with apparently prognostic heterogeneity. At present, the risk stratification of myeloma is still incomplete. Pyroptosis, a type of programmed cell death, has been shown to regulate tumor growth and may have potential prognostic value. However, the role of pyroptosis-related genes (PRGs) in MM remains undetermined. The aims of this study were to identify potential prognostic biomarkers and to construct a predictive model related to PRGs.

METHODS

Sequencing and clinical data were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Non-negative matrix factorization (NMF) was performed to identify molecular subtype screening. LASSO regression was used to screen for prognostic markers, and then a risk score model was constructed. The Maxstat package was utilized to calculate the optimal cutoff value, according to which patients were divided into a high-risk group and a low-risk group, and the survival curves were plotted using the Kaplan-Meier (K-M) method. Nomograms and calibration curves were established using the rms package.

RESULTS

A total of 33 PRGs were extracted from the TCGA database underlying which 4 MM molecular subtypes were defined. Patients in cluster 1 had poorer survival than those in cluster 2 (p = 0.035). A total of 9 PRGs were screened out as prognostic markers, and the predictive ability of the 9-gene risk score for 3-year survival was best (AUC = 0.658). Patients in the high-risk group had worse survival than those in the low-risk group (p < 0.001), which was consistent with the results verified by the GSE2658 dataset. The nomogram constructed by gender, age, International Staging System (ISS) stage, and risk score had the best prognostic predictive performance with a c-index of 0.721.

CONCLUSION

Our model could enhance the predictive ability of ISS staging and give a reference for clinical decision-making. The new, prognostic, and pyroptosis-related markers screened out by us may facilitate the development of novel risk stratification for MM.

CLINICAL TRIAL REGISTRATION

Not applicable.

G-Quadruplex Structures as a "Switch" Regulate ATF4 Expression in Ferroptotic HepG2 Cells

G-quadruplex (G4) is a noncanonical structure folded in a widespread manner by guanine-rich tandem repeated sequences. As a key response factor, activating transcription factor 4 (ATF4) has dual functions in managing iron-dependent ferroptosis by regulating amino acid synthesis and antioxidant-related gene expression. In our study, the activity of ATF4 expression was elevated in HepG2 cells induced by erastin. Based on preliminary bioinformatics analyses, the G-tract region, named WT, had high potential to form G4, and it was found that PDS could markedly weaken the increase of ATF4 expression by reducing the sensitivity of HepG2 cells toward erastin. In circular dichroism spectra, WT oligonucleotides showed characteristic molar ellipticity at specific wavelengths of parallel G4 structures, while corresponding single-base mutants possessed a weaker ability to form G4, which were consistent with immunostaining results. In addition, endogenous G4 formed by the WT motif was significantly destroyed in HepG2 cells treated with erastin. After being transfected with WT oligonucleotides, the levels of ATF4 mRNA decreased significantly regardless of being treated with erastin or not. Meanwhile, mutations of G-tracts could advantageously impact the luciferase expression downstream of an ATF4 promoter in reporter assays, manifesting that the decrease of endogenous G4 in the ATF4 promoter was positively associated with the expression enhanced by erastin in HepG2 cells.

Pyroptosis predicts immunotherapy outcomes across multiple cancer types

Pyroptosis is a programmed cell death characterized by inflammation and may coordinate with cancer immunotherapy, but assessments of pyroptosis in patients with immunotherapy are lacking. We evaluated the pyroptosis potentials in 71 cohorts with 24,388 cancer patients. They were elevated in tumors compared to normal tissues but had a weak relationship with prognosis. High pyroptosis potentials indicated "hot tumors" characteristics and high objective response rates to PD1/PDL1 inhibitors derived from clinical trials. In 15 cohorts with patients treated with immunotherapy, a pyroptosis score showed predictive values in objective response rate, progression-free survival, and overall survival. Systematic treatments, such as chemotherapy or endocrine therapy, enhanced pyroptosis in drug-resistant tumors. These results were further validated in three independent clinical cohorts and our two institutional cohorts by immunohistochemistry. Our findings uncover a value of pyroptosis potentials to predict immunotherapy responses and a theoretical rationale for combining pyroptosis inducers and immunotherapy in cancer treatment.

Gambogic Acid Induces Pyroptosis of Colorectal Cancer Cells through the GSDME-Dependent Pathway and Elicits an Antitumor Immune Response

Pyroptosis is a recently identified form of programmed cell death (PCD) that exerts a vital influence on the antitumor immune response. GA, a xanthone structure isolated from gamboge resin, is a naturally occurring bioactive ingredient with several anticancer activities, such as activities that affect cell cycle arrest, apoptosis, and autophagy. Here, we found that GA decreased the viability of the CRC cell lines, HCT116 and CT26, in a dose- and time-dependent manner, and multiple pores and large bubbles in the membranes, which are morphological characteristics of pyroptosis, were observed by light microscopy and transmission electron microscopy (TEM). Furthermore, the cleavage of gasdermin E (GSDME) was observed after exposure to GA, along with concomitant activation of caspase-3. Additionally, GSDME-dependent pyroptosis triggered by GA could be attenuated by siRNA-mediated knockdown of GSDME and treatment with the caspase-3 inhibitor. Moreover, we found that GA induced pyroptosis and significantly inhibited tumor growth in CT26 tumor-bearing mice. Strikingly, significantly increased proportions of CD3⁺ T cells, cytotoxic T lymphocytes (CTLs), and dendritic cells (DCs) were observed in the tumor microenvironment in the GA-treated groups. Moreover, significantly increased proportions of CTLs and effector memory T cells (TEM) (CD8⁺ CD44⁺ CD62L^-) were also detected in the spleens of the GA-treated groups, suggesting that the pyroptosis-induced immune response generated a robust memory response that mediated protective immunity. In this study, we revealed a previously unrecognized mechanism by which GA induces GSDME-dependent pyroptosis and enhances the anticancer immune response. Based on this mechanism, GA is a promising antitumor drug for CRC treatment that induces caspase-3-GSDME-dependent pyroptosis. This study provides novel insight into cancer chemoimmunotherapy.

Cell Death Triggers Induce MLKL Cleavage in Multiple Myeloma Cells, Which may Promote Cell Death

Necroptosis is a type of caspase-independent programmed cell death that has been implicated in cancer development. Activation of the canonical necroptotic pathway is often characterized with successive signaling events as the phosphorylation of mixed lineage kinase domain-like (MLKL) by receptor-interacting protein kinase-3 (RIPK3), followed by MLKL oligomerization and plasma membrane rupture. Here, we demonstrate that omega-3 polyunsaturated fatty acids DHA/EPA and the proteasome inhibitor bortezomib induce necroptosis in human multiple myeloma (MM) cells in a RIPK3 independent manner. In addition, it seemed to be that phosphorylation of MLKL was not essential for necroptosis induction in MM cells. We show that treatment of MM cells with these cytotoxic compounds induced cleavage of MLKL into a 35 kDa protein. Furthermore, proteolytic cleavage of MLKL was triggered by activated caspase-3/8/10, and mutation of Asp140Ala in MLKL blocked this cleavage. The pan-caspase inhibitor ZVAD-FMK efficiently prevented DHA/EPA and bortezomib induced cell death. In addition, nuclear translocation of total MLKL and the C-terminus were detected in treated MM cells. Collectively, this present study suggests that caspase-mediated necroptosis may occur under (patho)physiological conditions, delineating a novel regulatory mechanism of necroptosis in RIPK3-deficient cancer cells.

Integrative Analysis of a Pyroptosis-Related Signature of Clinical and Biological Value in Multiple Myeloma

Purpose

Pyroptosis is an inflammation-based programmed cell death that holds great potential as a novel cancer therapeutic target in patients with multiple myeloma (MM). However, thus far, the function of pyroptosis-related genes (PRGs) in MM and their prognostic relevance remains undetermined.

Methods

The model was established by the LASSO analysis, based on the Gene Expression Omnibus (GEO) dabatase, and its efficacy was verified using two external datasets. The model’s predictive ability was assessed by the Kaplan-Meier survival and time-dependent receiver operating characteristic (ROC) curves. Finally, a nomogram was established for clinical application. We also confirmed the validity of our model using specimens and in vitro experiments.

Results

We established an 11-PRG signature profile, and verified its efficacy using two validation cohorts (VCs). In both cohorts, patients were separated into two subpopulations, according to their median risk scores (RS). Our analysis revealed that high-risk (HR) patients experienced considerably lower overall survival (OS), compared to the low-risk (LR) patients. Using functional enrichment and immune infiltration analyses, we demonstrated that the immunologic status was strongly related to RS. Furthermore, using a pyroptosis inhibitor Q-VD-OPh, we revealed that MM cell proliferation and progression was drastically suppressed and the doxorubicin (DOX)-induced apoptosis was reversed.

Conclusion

Based on our analysis, pyroptosis not only serves as a measure of MM treatment efficiency and patient prognosis, but is also a possible target for anti-MM therapy.

Links Between N6-Methyladenosine and Tumor Microenvironments in Colorectal Cancer

N⁶-methyladenosine (m⁶A) is a critical epigenetic modification for tumor malignancies, but its role in regulating the tumor microenvironments (TMEs) has not been fully studied. By integrating multiple data sets and multi-omics data, we comprehensively evaluated the m⁶A “writers,” “erasers,” and “readers” in colorectal cancer and their association with TME characteristics. The m⁶A regulator genes showed specific patterns in co-mutation, copy number variation, and expression. Based on the transcriptomic data of the m⁶A regulators and their correlated genes, two types of subtyping systems, m⁶A_regCluster and m⁶A_sigCluster, were developed. The clusters were distinct in pathways (metabolism/inflammation/extracellular matrix and interaction), immune phenotypes (immune-excluded/immune-inflamed/immune-suppressive), TME cell composition (lack immune and stromal cells/activated immune cells/stromal and immune-suppressive cells), stroma activities, and survival outcomes. We also established an m⁶Ascore associated with molecular subgroups, microsatellite instability, DNA repair status, mutation burdens, and survival and predicted immunotherapy outcomes. In conclusion, our work revealed a close association between m⁶A modification and TME formation. Evaluating m⁶A in cancer has helped us comprehend the TME status, and targeting m⁶A in tumor cells might help modulate the TME and improve tumor therapy and immunotherapy.

MYC inhibitors in multiple myeloma

The importance of MYC function in cancer was discovered in the late 1970s when the sequence of the avian retrovirus that causes myelocytic leukemia was identified. Since then, over 40 years of unceasing research have highlighted the significance of this protein in malignant transformation, especially in hematologic diseases. Indeed, some of the earliest connections among the higher expression of proto-oncogenes (such as MYC), genetic rearrangements and their relation to cancer development were made in Burkitt lymphoma, chronic myeloid leukemia and mouse plasmacytomas. Multiple myeloma (MM), in particular, is a plasma cell malignancy strictly associated with MYC deregulation, suggesting that therapeutic strategies against it would be beneficial in treating this disease. However, targeting MYC was - and, somehow, still is - challenging due to its unique properties: lack of defined three-dimensional structure, nuclear localization and absence of a targetable enzymatic pocket. Despite these difficulties, however, many studies have shown the potential therapeutic impact of direct or indirect MYC inhibition. Different molecules have been tested, in fact, in the context of MM. In this review, we summarize the current status of the different compounds, including the results of their clinical testing, and propose to continue with the efforts to identify, repurpose, redesign or improve drug candidates to combine them with standard of care therapies to overcome resistance and enable better management of myeloma treatment.

Inflammation-related pyroptosis, a novel programmed cell death pathway, and its crosstalk with immune therapy in cancer treatment

In recent decades, chemotherapies targeting apoptosis have emerged and demonstrated remarkable achievements. However, emerging evidence has shown that chemoresistance is mediated by impairing or bypassing apoptotic cell death. Several novel types of programmed cell death, such as ferroptosis, necroptosis, and pyroptosis, have recently been reported to play significant roles in the modulation of cancer progression and are considered a promising strategy for cancer treatment. Thus, the switch between apoptosis and pyroptosis is also discussed. Cancer immunotherapy has gained increasing attention due to breakthroughs in immune checkpoint inhibitors; moreover, ferroptosis, necroptosis, and pyroptosis are highly correlated with the modulation of immunity in the tumor microenvironment. Compared with necroptosis and ferroptosis, pyroptosis is the primary mechanism for host defense and is crucial for bridging innate and adaptive immunity. Furthermore, recent evidence has demonstrated that pyroptosis exerts benefits on cancer immunotherapies, including immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell therapy (CAR-T). Hence, in this review, we elucidate the role of pyroptosis in cancer progression and the modulation of immunity. We also summarize the potential small molecules and nanomaterials that target pyroptotic cell death mechanisms and their therapeutic effects on cancer.

Transcription/Replication Conflicts in Tumorigenesis and Their Potential Role as Novel Therapeutic Targets in Multiple Myeloma

Simple Summary

Multiple myeloma is a hematologic cancer characterized by the accumulation of malignant plasma cells in the bone marrow. It remains a mostly incurable disease due to the inability to overcome refractory disease and drug-resistant relapse. Oncogenic transformation of PC in multiple myeloma is thought to occur within the secondary lymphoid organs. However, the precise molecular events leading to myelomagenesis remain obscure. Here, we identified genes involved in the prevention and the resolution of conflicts between the replication and transcription significantly overexpressed during the plasma cell differentiation process and in multiple myeloma cells. We discussed the potential role of these factors in myelomagenesis and myeloma biology. The specific targeting of these factors might constitute a new therapeutic strategy in multiple myeloma.

Abstract

Plasma cells (PCs) have an essential role in humoral immune response by secretion of antibodies, and represent the final stage of B lymphocytes differentiation. During this differentiation, the pre-plasmablastic stage is characterized by highly proliferative cells that start to secrete immunoglobulins (Igs). Thus, replication and transcription must be tightly regulated in these cells to avoid transcription/replication conflicts (TRCs), which could increase replication stress and lead to genomic instability. In this review, we analyzed expression of genes involved in TRCs resolution during B to PC differentiation and identified 41 genes significantly overexpressed in the pre-plasmablastic stage. This illustrates the importance of mechanisms required for adequate processing of TRCs during PCs differentiation. Furthermore, we identified that several of these factors were also found overexpressed in purified PCs from patients with multiple myeloma (MM) compared to normal PCs. Malignant PCs produce high levels of Igs concomitantly with cell cycle deregulation. Therefore, increasing the TRCs occurring in MM cells could represent a potent therapeutic strategy for MM patients. Here, we describe the potential roles of TRCs resolution factors in myelomagenesis and discuss the therapeutic interest of targeting the TRCs resolution machinery in MM.

On the Road to Fight Cancer: The Potential of G-quadruplex Ligands as Novel Therapeutic Agents

Nucleic acid sequences able to adopt a G-quadruplex conformation are overrepresented within the human genome. This evidence strongly suggests that these genomic regions have been evolutionary selected to play a pivotal role in several aspects of cell biology. In the present review article, we provide an overview on the biological impact of targeting G-quadruplexes in cancer. A variety of small molecules showing good G-quadruplex stabilizing properties has been reported to exert an antitumor activity in several preclinical models of human cancers. Moreover, promiscuous binders and multiple targeting G-quadruplex ligands, cancer cell defense responses and synthetic lethal interactions of G-quadruplex targeting have been also highlighted. Overall, evidence gathered thus far indicates that targeting G-quadruplex may represent an innovative and fascinating therapeutic approach for cancer. The continued methodological improvements, the development of specific tools and a careful consideration of the experimental settings in living systems will be useful to deepen our knowledge of G-quadruplex biology in cancer, to better define their role as therapeutic targets and to help design and develop novel and reliable G-quadruplex-based anticancer strategies.

G-quadruplex stabilization via small-molecules as a potential anti-cancer strategy

G-quadruplexes (G4) are secondary four-stranded DNA helical structures consisting of guanine-rich nucleic acids, which can be formed in the promoter regions of several genes under proper conditions. Several cancer cells have been shown to emerge from genomic changes in the expression of crucial growth-regulating genes that allow cells to develop and begin to propagate in an undifferentiated state. Recent attempts have focused on producing treatments targeted at particular protein products of genes that are abnormally expressed. Many of the proteins found are hard to target and considered undruggable due to structural challenges, protein overexpression, or mutations that affect treatment resistance. The utilization of small molecules that stabilize secondary DNA structures existing in several possible oncogenes' promoters and modulate their transcription is a new strategy that avoids some of these problems. In this review, we outline the function of G-quadruplex stabilization in cancer by small-molecules with the aim to improve cancer therapy.

Capitalizing on Synthetic Lethality of MYC to Treat Cancer in the Digital Age

Deregulation of MYC is among the most frequent oncogenic drivers of cancer. Developing targeted therapies against MYC is, therefore, one of the most critical unmet needs of cancer therapy. Unfortunately, MYC has been labelled as undruggable due to the lack of success in developing clinically relevant MYC-targeted therapies. Synthetic lethality is a promising approach that targets MYC-dependent vulnerabilities in cancer. However, translating the synthetic lethality targets to the clinics is still challenging due to the complex nature of cancers. This review highlights the most promising mechanisms of MYC synthetic lethality and how these discoveries are currently translated into the clinic. Finally, we discuss how in silico computational platforms can improve clinical success of synthetic lethality-based therapy.