Autophagy constitutes a major cell-protective mechanism that eliminates damaged components and maintains energy homeostasis via recycling nutrients under normal/stressed conditions. Although the ...core components of autophagy have been well studied, regulation of autophagy at the transcriptional level is poorly understood. Herein, we establish ZKSCAN3, a zinc finger family DNA-binding protein, as a transcriptional repressor of autophagy. Silencing of ZKSCAN3 induced autophagy and increased lysosome biogenesis. Importantly, we show that ZKSCAN3 represses transcription of a large gene set (>60) integral to, or regulatory for, autophagy and lysosome biogenesis/function and that a subset of these genes, including Map1lC3b and Wipi2, represent direct targets. Interestingly, ZKSCAN3 and TFEB are oppositely regulated by starvation and in turn oppositely regulate lysosomal biogenesis and autophagy, suggesting that they act in conjunction. Altogether, our study uncovers an autophagy master switch regulating the expression of a transcriptional network of genes integral to autophagy and lysosome biogenesis/function.
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► Silencing of ZKSCAN3 induces autophagy and lysosome biogenesis ► ZKSCAN3 transcriptionally regulates an extensive set of genes involved in autophagy ► ZKSCAN3 nuclear localization is regulated by nutrient availability ► ZKSCAN3 and TFEB regulate autophagy in opposite directions
Triple negative breast cancers (TNBCs) are known to express low PGR, ESR1, and ERBB2, and high KRT5, KRT14, and KRT17. However, the reasons behind the increased expressions of KRT5, KRT14, KRT17 and ...decreased expressions of PGR, ESR1, and ERBB2 in TNBCs are not fully understood. Here we show that, expression of chromosome 19 miRNA cluster (C19MC) specifically marks human TNBCs. Low REST and high CEBPB correlate with expression of C19MC, KRT5, KRT14, and KRT17 and enhancers of these genes/cluster are regulated by CEBPB and REST binding sites. The C19MC miRNAs in turn can potentially target REST to offer a positive feedback loop, and might target PGR, ESR1, ERBB2, GATA3, SCUBE2, TFF3 mRNAs to contribute towards TNBC phenotype. Thus our study demonstrates that C19MC miRNA expression marks TNBCs and that C19MC miRNAs and CEBPB might together determine the TNBC marker expression pattern.
Abstract
Metastasis is a pivotal event that accelerates the prognosis of cancer patients towards mortality. Therapies that aim to induce cell death in metastatic cells require a more detailed ...understanding of the metastasis for better mitigation. Towards this goal, we discuss the details of two distinct but overlapping pathways of metastasis: a classical reversible epithelial-to-mesenchymal transition (hybrid-EMT)-driven transport pathway and an alternative cell death process-driven blebbishield metastatic-witch (BMW) transport pathway involving reversible cell death process. The knowledge about the EMT and BMW pathways is important for the therapy of metastatic cancers as these pathways confer drug resistance coupled to immune evasion/suppression. We initially discuss the EMT pathway and compare it with the BMW pathway in the contexts of coordinated oncogenic, metabolic, immunologic, and cell biological events that drive metastasis. In particular, we discuss how the cell death environment involving apoptosis, ferroptosis, necroptosis, and NETosis in BMW or EMT pathways recruits immune cells, fuses with it, migrates, permeabilizes vasculature, and settles at distant sites to establish metastasis. Finally, we discuss the therapeutic targets that are common to both EMT and BMW pathways.
Smac mimetic overcomes resistance of bladder cancer cells to BCG‐stimulated neutrophils through TNF‐α.
BCG, the current gold standard immunotherapy for bladder cancer, exerts its activity via ...recruitment of neutrophils to the tumor microenvironment. Many patients do not respond to BCG therapy, indicating the need to understand the mechanism of action of BCG‐stimulated neutrophils and to identify ways to overcome resistance to BCG therapy. Using isolated human neutrophils stimulated with BCG, we found that TNF‐α is the key mediator secreted by BCG‐stimulated neutrophils. RT4v6 human bladder cancer cells, which express TNFR1, CD95/Fas, CD95 ligand/FasL, DR4, and DR5, were resistant to BCG‐stimulated neutrophil conditioned medium but effectively killed by the combination of conditioned medium and Smac mimetic. rhTNF‐α and rhFasL, but not rhTRAIL, in combination with Smac mimetic, generated signature molecular events similar to those produced by BCG‐stimulated neutrophils in combination with Smac mimetic. However, experiments using neutralizing antibodies to these death ligands showed that TNF‐α secreted from BCG‐stimulated neutrophils was the key mediator of anticancer action. These findings explain the mechanism of action of BCG and identified Smac mimetics as potential combination therapeutic agents for bladder cancer.
Undifferentiated embryonal sarcoma of the liver (UESL) is a rare and aggressive malignancy. Though the molecular underpinnings of this cancer have been largely unexplored, recurrent chromosomal ...breakpoints affecting a noncoding region on chr19q13, which includes the chromosome 19 microRNA cluster (C19MC), have been reported in several cases. We performed comprehensive molecular profiling on samples from 14 patients diagnosed with UESL. Congruent with prior reports, we identified structural variants in chr19q13 in 10 of 13 evaluable tumors. From whole transcriptome sequencing, we observed striking expressional activity of the entire C19MC region. Concordantly, in 7 of 7 samples undergoing miRNAseq, we observed hyperexpression of the miRNAs within this cluster to levels >100 fold compared to matched normal tissue or a non-C19MC amplified cancer cell line. Concurrent TP53 mutation or copy number loss was identified in all evaluable tumors with evidence of C19MC overexpression. We find that C19MC miRNAs exhibit significant negative correlation to TP53 regulatory miRNAs and K-Ras regulatory miRNAs. Using RNA-seq we identified that pathways relevant to cellular differentiation as well as mRNA translation machinery are transcriptionally enriched in UESL. In summary, utilizing a combination of next-generation sequencing and high-density arrays we identify the combination of C19MC hyperexpression via chromosomal structural event with TP53 mutation or loss as highly recurrent genomic features of UESL.
Cancer cells are capable of sphere formation (transformation) through reactive oxygen species (ROS) and glycolysis shift. Transformation is linked to tumorigenesis and therapy resistance, hence ...targeting regulators of ROS and glycolysis is important for cancer therapeutic candidates. Here, we demonstrate that Smac mimetic AZ58 in combination with tumour necrosis factor-α (TNF-α) was able to inhibit the production of ROS, inhibit glycolysis through Pim-1 kinase-mediated Ser-112 phosphorylation of BAD, and increase depolarization of mitochondria. We also identified mitochondrial isoforms of Pim-1 kinase that were targeted for degradation by AZ58 in combination with TNF-α or AZ58 in combination with Fas ligand (FasL) plus cycloheximide (CHX) through caspase-3 to block transformation. Our study demonstrates that Smac mimetic in combination with TNF-α is an ideal candidate to target Pim-1 expression, inhibit ROS production and to block transformation from blebbishields.
Abstract
A subset of hepatocellular carcinoma (HCC) overexpresses the chromosome 19 miRNA cluster (C19MC) and is associated with an undifferentiated phenotype marked by overexpression of cancer ...testis antigens (CTAs) including anti-apoptotic melanoma-A antigens (MAGEAs). However, the regulation of C19MC miRNA and MAGEA expression in HCCs are not understood. Here we show that, C19MC overexpression is tightly linked to a sub-set of HCCs with transcription-incompetent p53. Using next-generation and Sanger sequencing we found that, p53 in Hep3B cells is impaired by TP53-FXR2 fusion, and that overexpression of the C19MC miRNA-520G in Hep3B cells promotes the expression of MAGEA-3, 6 and 12 mRNAs. Furthermore, overexpression of p53-R175H and p53-R273H mutants promote miR-520G and MAGEA RNA expression and cellular transformation. Moreover, IFN-γ co-operates with miR-520G to promote MAGEA expression. On the other hand, metals such as nickel and zinc promote miR-526B but not miR-520G, to result in the suppression of MAGEA mRNA expression, and evoke cell death through mitochondrial membrane depolarization. Therefore our study demonstrates that a MAGEA-promoting network involving miR-520G, p53-defects and IFN-γ that govern cellular transformation and cell survival pathways, but MAGEA expression and survival are counteracted by nickel and zinc combination.
Bladder cancer stem cell research is rapidly expanding based on the knowledge of cancer stem cells from various cancer types and normal stem cells as models. In various cancer types, cancer stem ...cells have been implicated in therapeutic resistance and relapse after initial therapy. Understanding how cancer stem cells differ from bulk cancer cells and how cancer stem cells contribute to relapse and resistance are essential to develop novel therapeutics to target cancer stem cells effectively. Here we review the latest information on bladder cancer stem cells, their biological characteristics, including their response to treatment, recurrence, immune context and technical problems encountered in bladder cancer stem cell research.
Cellular transformation is a major event that helps cells to evade apoptosis, genomic instability checkpoints, and immune surveillance to initiate tumorigenesis and to promote progression by cancer ...stem cell expansion. However, the key molecular players that govern cellular transformation and ways to target cellular transformation for therapy are poorly understood to date. Here we draw key evidences from the literature on K-Ras-driven cellular transformation in the context of apoptosis to shed light on the key players that are required for cellular transformation and explain how aiming p53 could be useful to target cellular transformation. The defects in key apoptosis regulators such as p53, Bax, and Bak lead to apoptosis evasion, cellular transformation, and genomic instability to further lead to stemness, tumorigenesis, and metastasis via c-Myc-dependent transcription. Therefore enabling key apoptotic checkpoints in combination with K-Ras inhibitors will be a promising therapeutic target in cancer therapy.
Intravesical bacillus Calmette-Guérin (BCG) immunotherapy results in neutrophil recruitment and subsequent secretion of cytokines to eliminate non-muscle invasive bladder cancer cells. However, ...bladder cancer cells often resist BCG immunotherapy. Thus, understanding the mechanism of action of BCG, and designing appropriate combination therapies might help to overcome BCG resistance and redirect neutrophils against bladder cancer cells.
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