Novel cancer stem cell marker MVP enhances temozolomide-resistance in glioblastoma

Stemness regulation in prostate cancer: prostate cancer stem cells and targeted therapy

BACKGROUND

Increasing evidence indicates that cancer stem cells (CSCs) and cancer stem-like cells form a special subpopulation of cells that are ubiquitous in tumors. These cells exhibit similar characteristics to those of normal stem cells in tissues; moreover, they are capable of self-renewal and differentiation, as well as high tumorigenicity and drug resistance. In prostate cancer (PCa), it is difficult to kill these cells using androgen signaling inhibitors and chemotherapy drugs. Consequently, the residual prostate cancer stem cells (PCSCs) mediate tumor recurrence and progression.

OBJECTIVE

This review aims to provide a comprehensive and up-to-date overview of PCSCs, with a particular emphasis on potential therapeutic strategies targeting these cells.

METHODS

After searching in PubMed and Embase databases using 'prostate cancer' and 'cancer stem cells' as keywords, studies related were compiled and examined.

RESULTS

In this review, we detail the origin and characteristics of PCSCs, introduce the regulatory pathways closely related to CSC survival and stemness maintenance, and discuss the link between epithelial-mesenchymal transition, tumor microenvironment and tumor stemness. Furthermore, we introduce the currently available therapeutic strategies targeting CSCs, including signaling pathway inhibitors, anti-apoptotic protein inhibitors, microRNAs, nanomedicine, and immunotherapy. Lastly, we summarize the limitations of current CSC research and mention future research directions.

CONCLUSION

A deeper understanding of the regulatory network and molecular markers of PCSCs could facilitate the development of novel therapeutic strategies targeting these cells. Previous preclinical studies have demonstrated the potential of this treatment approach. In the future, this may offer alternative treatment options for PCa patients.

Notch1 and Major Vault Proteins Modulate Temozolomide Resistance in Glioblastoma

The development of resistance to chemotherapy in the case of aggressive glioblastoma multiforme (GBM) presents a significant treatment challenge. Dysregulation of the Notch signalling pathway promotes tumour proliferation in GBM cells. This study was that targeting the Notch signalling pathway could be a potential therapeutic approach for GBM. Initially, temozolomide-(TMZ)-resistant GBM cells were generated, and the effect of Notch1 on the expression of multiple resistance proteins within these cells was investigated. Subsequently, the expression of Notch-1 in GBM cells was reduced using siRNA. Results revealed a significant reduction in TMZ sensitivity in TMZ-resistant GBM cells, accompanied by a substantial increase in the expression of major vault protein-(MVP), O6-methylguanine-DNA-methyltransferase-(MGMT), and ATP-binding-cassette transporter-G2-(ABCG2). Furthermore, TMZ-resistant U87-R and U251-R cells exhibited higher proliferation rates compared to their parental control cells (U87 and U251). Additionally, we observed that downregulating Notch-1 signalling inhibited the proliferation of TMZ-resistant U87-R and U251-R cells. This downregulation led to the inactivation of MGMT, ABCG2, and MVP. Importantly, it increased chemosensitivity to TMZ, particularly by downregulating MVP expression. Consequently, Notch1 could serve as a potential therapeutic target for GBM cells and may be effective in preventing TMZ resistance by targeting MVP, as well as MGMT and ABCG2 in GBM cells.

Vault Particles in Cancer Progression, Multidrug Resistance, and Drug Delivery: Current Insights and Future Applications

Vault particles (VPs) are highly conserved large ribonucleoprotein complexes found exclusively in eukaryotes. They play critical roles in various cellular processes, but their involvement in cancer progression and multidrug resistance (MDR) is the most extensively studied. VPs are composed of the major vault protein (MVP), vault RNAs (vtRNAs), vault poly (ADP-ribose) polymerase, and telomerase-associated protein-1. These components are involved in the regulation of signaling pathways that affect tumor survival, proliferation, and metastasis. MVP has been associated with aggressive tumor phenotypes, while vtRNAs modulate cell proliferation, apoptosis, and autophagy. VPs also contribute to MDR by sequestering chemotherapeutic agents, altering their accumulation in the nucleus, and regulating lysosomal dynamics. Furthermore, small vault RNA-derived fragments participate in gene silencing and intercellular communication, reinforcing the role of precursors of vtRNAs in cancer development. Beyond their biological roles, VPs present a promising platform for drug delivery, due to their unique ability to encapsulate a wide range of biomolecules and therapeutic agents, followed by controlled release. This review compiles data from PubMed and Scopus, with a literature search conducted up until December 2024, highlighting current knowledge regarding VPs and their crucial involvement in cancer-related mechanisms and their applications in overcoming cancer drug resistance.

Unraveling the role of Major Vault Protein as a novel immune-related biomarker that promotes the proliferation and migration in pancreatic adenocarcinoma

Background

Pancreatic adenocarcinoma (PAAD) is a formidable challenge in oncology research, with a complex pathogenesis that requires to be explored. Major Vault Protein (MVP) is the principal structural component of the vault complex, and its expression level is remarkably upregulated in various cancers. Extensive investigations have been conducted to explore the role of MVP in specific cancer contexts, yet the potential molecular mechanisms and biological functions of MVP in PAAD still remain considerably elusive. This study aims to explore the role of MVP as a novel immune-related biomarker in the pathogenesis and clinical treatment of PAAD.

Methods

Gene expression data and clinical information were collected from TCGA, GTEx and GEO databases. Survival, prognostic and functional enrichment analysis were employed with R software. Immunological correlation analysis was performed using TIMER2.0, TIDE scores, TISIDB and TISCH. Epigenetic analysis was implemented by MethSurv, CPTAC, UALCAN, and cBioPortal. Drug analysis was conducted using Enrichr and CellMiner. Moreover, cellular experiments, like RNA interference, qRT-PCR, Western blot, cell cycle analysis, cell apoptosis analysis, colony formation assay, transwell assay, and wound healing assay, were performed for verifying the functional properties of MVP in the PAAD progression.

Results

We demonstrated an abnormally upregulated expression of MVP in PAAD tissues, which notably correlated with an adverse prognosis in PAAD patients. Functional analysis suggested the conceivable involvement of MVP in immune modulation, and immunotherapy. Additionally, we identified genetic alterations, reduced promoter methylation, and heightened phosphorylation in MVP. We also clarified Suloctidil and Tetradioxin as the most notable potential drugs targeting MVP in PAAD. Moreover, our experimental observations consistently highlighted the significant impact of MVP deficiency on impeding PAAD cell proliferation, inhibiting cell migration, and accelerating cell apoptosis. Interestingly, a potential link between MVP and ERK or AKT pathways was displayed, which opens new avenues for further exploration of the molecular mechanisms of MVP-targeted therapies in PAAD.

Conclusions

This study systematically describes MVP as an immune-related biomarker with remarkable potential for predicting the prognosis, tumor progression and immunotherapeutic efficacy in PAAD.

Molecular targets, therapeutic agents and multitasking nanoparticles to deal with cancer stem cells: A narrative review

There is increasing evidence that malignant tumors are initiated and maintained by a sub-population of tumor cells that have similar biological properties to normal adult stem cells. This very small population of Cancer Stem Cells (CSC) comprises tumor initiating cells responsible for cancer recurrence, drug resistance and metastasis. Conventional treatments such as chemotherapy, radiotherapy and surgery, in addition to being potentially toxic and non-specific, may paradoxically increase the population, spread and survival of CSCs. Next-generation sequencing and omics technologies are increasing our understanding of the pathways and factors involved in the development of CSCs, and can help to discover new therapeutic targets against CSCs. In addition, recent advances in nanomedicine have provided hope for the development of optimal specific therapies to eradicate CSCs. Moreover, the use of artificial intelligence and nano-informatics can elucidate new drug targets, and help to design drugs and nanoparticles (NPs) to deal with CSCs. In this review, we first summarize the properties of CSCs and describe the signaling pathways and molecular characteristics responsible for the emergence and survival of CSCs. Also, the location of CSCs within the tumor and the effect of host factors on the creation and maintenance of CSCs are discussed. Newly discovered molecular targets involved in cancer stemness and some novel therapeutic compounds to combat CSCs are highlighted. The optimum properties of anti-CSC NPs, including blood circulation and stability, tumor accumulation and penetration, cellular internalization, drug release, endosomal escape, and aptamers designed for specific targeting of CSCs are covered. Finally, some recent smart NPs designed for therapeutic and theranostic purposes to overcome CSCs are discussed.

Hypoxia-Driven M2-Polarized Macrophages Facilitate Cancer Aggressiveness and Temozolomide Resistance in Glioblastoma

Hypoxia-induced M2 phenotypes of tumor associated macrophages (TAMs) promote the development and chemoresistance of multiple types of cancers, including glioblastoma (GBM). However, the detailed molecular mechanisms have not been fully understood. In this study, we firstly reported that hypoxic pressure promoted M2 macrophage generation, which further promoted cancer progression and temozolomide (TMZ) resistance in GBM through secreting vascular endothelial growth factor (VEGF). Specifically, the clinical data suggested that M2 macrophages were significantly enriched in GBM tissues compared with the adjacent normal tissues, and the following in vitro experiments validated that hypoxic pressure promoted M2-polarized macrophages through upregulating hypoxia-inducible factor-1α (HIF-1α). In addition, hypoxic M2 macrophages VEGF-dependently promoted cell proliferation, epithelial-mesenchymal transition (EMT), glioblastoma stem cell (GSC) properties, and TMZ resistance in GBM cells through activating the PI3K/Akt/Nrf2 pathway. Also, M2 macrophages secreted VEGF to accelerate angiogenesis in human umbilical vein endothelial cells (HUVECs) through interacting with its receptor VEGFR. In general, we concluded that hypoxic M2 macrophages contributed to cancer progression, stemness, drug resistance, and angiogenesis in GBM through secreting VEGF, and our data supported the notion that targeting hypoxia-associated M2 macrophages might be an effective treatment strategy for GBM in clinical practices.

Molecular Pathways and Genomic Landscape of Glioblastoma Stem Cells: Opportunities for Targeted Therapy

Glioblastoma (GBM) is an aggressive tumor of the central nervous system categorized by the World Health Organization as a Grade 4 astrocytoma. Despite treatment with surgical resection, adjuvant chemotherapy, and radiation therapy, outcomes remain poor, with a median survival of only 14-16 months. Although tumor regression is often observed initially after treatment, long-term recurrence or progression invariably occurs. Tumor growth, invasion, and recurrence is mediated by a unique population of glioblastoma stem cells (GSCs). Their high mutation rate and dysregulated transcriptional landscape augment their resistance to conventional chemotherapy and radiation therapy, explaining the poor outcomes observed in patients. Consequently, GSCs have emerged as targets of interest in new treatment paradigms. Here, we review the unique properties of GSCs, including their interactions with the hypoxic microenvironment that drives their proliferation. We discuss vital signaling pathways in GSCs that mediate stemness, self-renewal, proliferation, and invasion, including the Notch, epidermal growth factor receptor, phosphatidylinositol 3-kinase/Akt, sonic hedgehog, transforming growth factor beta, Wnt, signal transducer and activator of transcription 3, and inhibitors of differentiation pathways. We also review epigenomic changes in GSCs that influence their transcriptional state, including DNA methylation, histone methylation and acetylation, and miRNA expression. The constituent molecular components of the signaling pathways and epigenomic regulators represent potential sites for targeted therapy, and representative examples of inhibitory molecules and pharmaceuticals are discussed. Continued investigation into the molecular pathways of GSCs and candidate therapeutics is needed to discover new effective treatments for GBM and improve survival.

Small but Powerful: The Human Vault RNAs as Multifaceted Modulators of Pro-Survival Characteristics and Tumorigenesis

Simple Summary

Small non-protein-coding RNAs have been recognized as valuable regulators of gene expression in all three domains of life. Particularly in multicellular organisms, ncRNAs-mediated gene expression control has evolved as a central principle of cellular homeostasis. Thus, it is not surprising that non-coding RNA misregulation has been linked to various diseases. Here, we review the contributions of the four human vault RNAs to cellular proliferation, apoptosis and cancer biology.

Abstract

The importance of non-coding RNAs for regulating gene expression has been uncovered in model systems spanning all three domains of life. More recently, their involvement in modulating signal transduction, cell proliferation, tumorigenesis and cancer progression has also made them promising tools and targets for oncotherapy. Recent studies revealed a class of highly conserved small ncRNAs, namely vault RNAs, as regulators of several cellular homeostasis mechanisms. The human genome encodes four vault RNA paralogs that share significant sequence and structural similarities, yet they seem to possess distinct roles in mammalian cells. The alteration of vault RNA expression levels has frequently been observed in cancer tissues, thus hinting at a putative role in orchestrating pro-survival characteristics. Over the last decade, significant advances have been achieved in clarifying the relationship between vault RNA and cellular mechanisms involved in cancer development. It became increasingly clear that vault RNAs are involved in controlling apoptosis, lysosome biogenesis and function, as well as autophagy in several malignant cell lines, most likely by modulating signaling pathways (e.g., the pro-survival MAPK cascade). In this review, we discuss the identified and known functions of the human vault RNAs in the context of cell proliferation, tumorigenesis and chemotherapy resistance.