bims-ectoca Biomed News
on Epigenetic control of tolerance in cancer
Issue of 2023–03–19
eleven papers selected by
Ankita Daiya, Birla Institute of Technology and Science



  1. J Gastroenterol Hepatol. 2023 Mar 12.
       AIM AND BACKGROUND: Yes-associated protein (YAP), a key transcriptional co-activator associated with cell fate and tumor progression, has been reported to be a powerful driver of hepatoblastoma (HB). In this study, we investigated the mechanism underlying oncogenic role of YAP in HB.
    METHODS: The expression of YAP in HB tissues was measured through WB and qRT-PCR. The IHC and IF were performed to determine the distribution of YAP. The phase separation of YAP was proved by living cell imaging and FRAP experiment. The effect of YAP phase separation in HB cells in vitro an in vivo were tested using CCK8, flow cytometry and xenograft tumors.
    RESULTS: YAP was overexpressed and activated in HB. Nuclear YAP formed an active transcriptional site via LLPS to recruit the crucial transcription factor TEAD4. Thus, YAP phase separation facilitated transcription of oncogenic genes and subsequently mediated chemoresistance of HB. Mechanistically, the phase separation ability of YAP depends on the coiled-coil domain, which is a typical phase-separation domain. The electrostatic interactions and hydrophobic interactions within YAP are also vital to YAP phase separation. More importantly, YAP inhibitor Verteporfin is potential treatment for HB and combination with cisplatin enhanced therapeutic efficacy.
    CONCLUSIONS: Highly expressed and active YAP exerts an oncogenic effect in HB via phase separation and provides new insights for the treatment of HB.
    Keywords:  YAP; chemoresistance; hepatoblastoma; phase separation
    DOI:  https://doi.org/10.1111/jgh.16173
  2. Biomaterials. 2023 Mar 07. pii: S0142-9612(23)00084-4. [Epub ahead of print]296 122076
      The tumor microenvironment is a complex and dynamic ecosystem composed of various physical cues and biochemical signals that facilitate cancer progression, and tumor-associated macrophages are especially of interest as a treatable target due to their diverse pro-tumorigenic functions. Engineered three-dimensional models of tumors more effectively mimic the tumor microenvironment than monolayer cultures and can serve as a platform for investigating specific aspects of tumor biology within a controlled setting. To study the combinatorial effects of tumor-associated macrophages and microenvironment mechanical properties on osteosarcoma, we co-cultured human osteosarcoma cells with macrophages within biomaterials-based bone tumor niches with tunable stiffness. In the first 24 h of direct interaction between the two cell types, macrophages induced an inflammatory environment consisting of high concentrations of tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 within moderately stiff scaffolds. Expression of Yes-associated protein (YAP), but not its homolog, transcriptional activator with PDZ-binding motif (TAZ), in osteosarcoma cells was significantly higher than in macrophages, and co-culture of the two cells slightly upregulated YAP in both cells, although not to a significant degree. Resistance to doxorubicin treatment in osteosarcoma cells was correlated with inflammation in the microenvironment, and signal transducer and activator of transcription 3 (STAT3) inhibition diminished the inflammation-related differences in drug resistance but ultimately did not improve the efficacy of doxorubicin. This work highlights that the biochemical cues conferred by tumor-associated macrophages in osteosarcoma are highly variable, and signals derived from the immune system should be considered in the development and testing of novel drugs for cancer.
    Keywords:  IL-6/STAT3; Osteosarcoma; Tissue engineered tumor model; Tumor microenvironment mechanical properties; Tumor-associated macrophages; YAP/TAZ
    DOI:  https://doi.org/10.1016/j.biomaterials.2023.122076
  3. J Pharm Anal. 2023 Feb;13(2): 127-141
      The reversible and precise temporal and spatial regulation of histone lysine methyltransferases (KMTs) is essential for epigenome homeostasis. The dysregulation of KMTs is associated with tumor initiation, metastasis, chemoresistance, invasiveness, and the immune microenvironment. Therapeutically, their promising effects are being evaluated in diversified preclinical and clinical trials, demonstrating encouraging outcomes in multiple malignancies. In this review, we have updated recent understandings of KMTs' functions and the development of their targeted inhibitors. First, we provide an updated overview of the regulatory roles of several KMT activities in oncogenesis, tumor suppression, and immune regulation. In addition, we summarize the current targeting strategies in different cancer types and multiple ongoing clinical trials of combination therapies with KMT inhibitors. In summary, we endeavor to depict the regulation of KMT-mediated epigenetic landscape and provide potential epigenetic targets in the treatment of cancers.
    Keywords:  Cancer; Clinical application; Combined therapeutic strategy; Epigenetic inhibitors; Epigenetics; Histone lysine methyltransferase
    DOI:  https://doi.org/10.1016/j.jpha.2022.11.009
  4. Am J Transl Res. 2023 ;15(2): 982-994
       OBJECTIVES: Ovarian cancer (OC) ranks fifth among the main causes of cancer-related deaths in women worldwide. PCLAF/KIAA0101 and Yes-associated protein (YAP) have been linked to several human malignant cancers, including OC. However, the roles of KIAA0101 and YAP in glycolysis-dependent OC cell proliferation remain unknown.
    METHODS: qRT-PCR and western blot were performed to analyze the KIAA0101 expression. Short hairpin RNA transfection was performed to silence KIAA0101 expression in cells. Cell viability and apoptosis were assayed by colony formation and flow cytometry, respectively. Glucose uptake, lactate production, and glycolytic enzyme expression were assessed to determine the level of cellular glycolysis. Phosphorylation and the nuclear localization of YAP were assessed to determine YAP activation.
    RESULTS: OC tissue and cell lines exhibited higher KIAA0101 expression than the non-cancerous tissues and cells. KIAA0101 silencing reduced the proliferation and increased the apoptosis of both A2780 and ES-2 OC cell lines. Furthermore, KIAA0101 depletion suppressed glycolysis and YAP activation, as evidenced by increased YAP phosphorylation and decreased nuclear localization. Reactivation of YAP was performed by administration of mitochonic acid 5 in both OC cell lines with KIAA0101 knockdown. Glucose uptake, lactate production, phosphofructokinase, pyruvate dehydrogenase beta, pyruvate kinase M2, triosephosphate isomerase 1, glucose-6-phosphate dehydrogenase, enolase 1, and lactate dehydrogenase expression levels in cells recovered after the reactivation of YAP. Additionally, YAP reactivation increased cell proliferation and inhibited apoptosis.
    CONCLUSIONS: This study showed that KIAA0101 could promote glycolysis during nasopharyngeal carcinoma development through YAP signaling activation, suggesting that KIAA0101 could serve as a target for OC treatment.
    Keywords:  KIAA0101; MA5; Ovarian cancer; Yes-associated protein; glycolysis
  5. Acta Biochim Biophys Sin (Shanghai). 2023 Mar 25.
      Gastric cancer (GC) is an aggressive malignant disease which still lacks effective early diagnosis markers and targeted therapies, representing the fourth-leading cause of cancer-associated death worldwide. The Hippo signaling pathway plays crucial roles in organ size control and tissue homeostasis under physiological conditions, yet its aberrations have been closely associated with several hallmarks of cancer. The last decade witnessed a burst of investigations dissecting how Hippo dysregulation contributes to tumorigenesis, highlighting the therapeutic potential of targeting this pathway for tumor intervention. In this review, we systemically document studies on the Hippo pathway in the contexts of gastric tumor initiation, progression, metastasis, acquired drug resistance, and the emerging development of Hippo-targeting strategies. By summarizing major open questions in this field, we aim to inspire further in-depth understanding of Hippo signaling in GC development, as well as the translational implications of targeting Hippo for GC treatment.
    Keywords:  Hippo pathway; YAP/TAZ; gastric cancer; mechanism; targeted therapy
    DOI:  https://doi.org/10.3724/abbs.2023038
  6. Oncotarget. 2023 Mar 11. 14 193-206
      Cancer therapy is limited by toxicity in normal cells and drug-resistance in cancer cells. Paradoxically, cancer resistance to certain therapies can be exploited for protection of normal cells, simultaneously enabling the selective killing of resistant cancer cells by using antagonistic drug combinations, which include cytotoxic and protective drugs. Depending on the mechanisms of drug-resistance in cancer cells, the protection of normal cells can be achieved with inhibitors of CDK4/6, caspases, Mdm2, mTOR, and mitogenic kinases. When normal cells are protected, the selectivity and potency of multi-drug combinations can be further enhanced by adding synergistic drugs, in theory, eliminating the deadliest cancer clones with minimal side effects. I also discuss how the recent success of Trilaciclib may foster similar approaches into clinical practice, how to mitigate systemic side effects of chemotherapy in patients with brain tumors and how to ensure that protective drugs would only protect normal cells (not cancer cells) in a particular patient.
    Keywords:  cyclotherapy; oncology; rapamycin; resistance; trilaciclib
    DOI:  https://doi.org/10.18632/oncotarget.28382
  7. Anal Chem. 2023 Mar 13.
      Circulating tumor cells (CTCs) are crucial in tumor progression and metastasis, but the knowledge of their roles grows slowly at single-cell levels. Characterizing the rarity and fragility of CTCs by nature, highly stable and efficient single-CTC sampling methods are still lacking, which impedes the development of single-CTC analysis. Herein, an improved, capillary-based single-cell sampling (SiCS) method, the so-called bubble-glue single-cell sampling (bubble-glue SiCS), is introduced. Benefiting from the characteristic that the cells tend to adhere to air bubbles in the solution, single cells can be sampled with bubbles as low as 20 pL with a self-designed microbubble-volume-controlled system. Benefiting from the excellent maneuverability, single CTCs are sampled directly from 10 μL volume of real blood samples after fluorescent labeling. Meanwhile, over 90% of the CTCs obtained survived and well proliferated after the bubble-glue SiCS process, which showed considerable superiority for downstream single-CTC profiling. Furthermore, a highly metastatic breast cancer model of the 4T1 cell line in vivo was employed for the real blood sample analysis. Increases in CTC numbers were observed during the tumor progression process, and significant heterogeneities among individual CTCs were discovered. In all, we propose a novel avenue for target SiCS and provide an alternative technique route for CTC separation and analysis.
    DOI:  https://doi.org/10.1021/acs.analchem.2c04994
  8. Mol Ther Nucleic Acids. 2023 Mar 14. 31 717-729
      Epigenetically switched, proliferative vascular smooth muscle cells (SMCs) form neointima, engendering stenotic diseases. Histone-3 lysine-27 trimethylation (H3K27me3) and acetylation (H3K27ac) marks are associated with gene repression and activation, respectively. The polycomb protein embryonic ectoderm development (EED) reads H3K27me3 and also enhances its deposition, hence is a canonical gene repressor. However, herein we found an unexpected role for EED in activating the bona fide pro-proliferative gene Ccnd1 (cyclinD1). EED overexpression in SMCs increased Ccnd1 mRNA, seemingly contradicting its gene-repressing function. However, consistently, EED co-immunoprecipitated with gene-activating H3K27ac reader BRD4, and they co-occupied at both mitogen-activated Ccnd1 and mitogen-repressed P57 (bona fide anti-proliferative gene), as indicated by chromatin immunoprecipitation qPCR. These results were abolished by an inhibitor of either the EED/H3K27me3 or BRD4/H3K27ac reader function. In accordance, elevating BRD4 increased H3K27me3. In vivo, while EED was upregulated in rat and human neointimal lesions, selective EED inhibition abated angioplasty-induced neointima and reduced cyclinD1 in rat carotid arteries. Thus, results uncover a previously unknown role for EED in Ccnd1 activation, likely via its cooperativity with BRD4 that enhances each other's reader function; i.e., activating pro-proliferative Ccnd1 while repressing anti-proliferative P57. As such, this study confers mechanistic implications for the epigenetic intervention of neointimal pathology.
    Keywords:  BRD4 in p57 repression; EED in Ccnd1 activation; MT: Oligonucleotides: Therapies and Applications; cooperativity between EED and BRD4; epigenetic readers; neointima; smooth muscle cell proliferation
    DOI:  https://doi.org/10.1016/j.omtn.2023.02.024
  9. Environ Toxicol. 2023 Mar 15.
       BACKGROUND: Osteosarcoma (OS) immune environment is complexed and the immune factors-related to OS progression need to be explored. Tumor-associated macrophages (TAMs) are regarded as immune suppressive and tumor-promoting cells. However, the underlying mechanisms through which TAMs function are still fragmentary. Here, we aim to explore the underlying mechanisms by which TAMs regulate OS progression.
    METHODS: TAMs from OS tissues were isolated by flow cytometry. Exosomes derived from TAMs were separated using ultracentrifugation and western blotting. Transmission electron microscopy (TEM), and flow cytometry were constructed to characterize TAMs-derived exosomes. Additionally, the differential MicroRNAs (miRNAs) and genes were detected through RNA sequencing, and further validated using real-time PCR (RT-PCR). OS cell metastasis ability was assessed using transwell invasion and scratch wound healing assays. MiRNAs mimic and lentiviral vectors were utilized to explore the effects on OS progression.
    RESULTS: Exosome secreted by TAMs accelerated the OS metastasis. Let-7a level was upregulated in TAMs derived exosomes, which downregulated C15orf41 by targeting 3'-untranslated region (UTR). Furthermore, overexpressing let-7a enhanced invasion and migration by blocking the transcription of C15orf41. In consistent, up-regulating let-7a promoted OS progression and made the prognosis to be worse, which can be reversed by C15orf41 overexpression.
    CONCLUSION: This study highlighted the critical role of TAMs-derived exosomes in OS progression and explored the potential value of the let-7a/C15orf41 axis as an indicator or target for OS.
    Keywords:  C15orf41; TAMs; exosomes; let-7a; metastasis; osteosarcoma
    DOI:  https://doi.org/10.1002/tox.23766
  10. Hum Genet. 2023 Mar 16.
      Nuclear speckles are small, membrane-less organelles that reside within the nucleus. Nuclear speckles serve as a regulatory hub coordinating complex RNA metabolism steps including gene transcription, pre-mRNA splicing, RNA modifications, and mRNA nuclear export. Reflecting the importance of proper nuclear speckle function in regulating normal human development, an increasing number of genetic disorders have been found to result from mutations in the genes encoding nuclear speckle proteins. To denote this growing class of genetic disorders, we propose "nuclear speckleopathies". Notably, developmental disabilities are commonly seen in individuals with nuclear speckleopathies, suggesting the particular importance of nuclear speckles in ensuring normal neurocognitive development. In this review article, a general overview of nuclear speckle function, and the current knowledge of the mechanisms underlying some nuclear speckleopathies, such as ZTTK syndrome, NKAP-related syndrome, TARP syndrome, and TAR syndrome, are discussed. These nuclear speckleopathies represent valuable models to understand the basic function of nuclear speckles and how its functional defects result in human developmental disorders.
    DOI:  https://doi.org/10.1007/s00439-023-02540-6
  11. Mol Oncol. 2023 Mar 17.
      LIM protein-domain containing protein Ajuba (encoded by AJUBA) functions as a scaffold protein to regulate protein-protein interactions, signaling transduction and genes transcription. AJUBA expression is higher in colorectal cancer (CRC) tissues compared with normal tissues, but its specific molecular function in CRC progression is still not very clear. Here, we found that, in CRC cancer cell lines, overexpression of AJUBA decreased p53 levels, whereas knockdown of AJUBA significantly increased p53 levels. Although the presence of Ajuba did not influence p53 transcription, it formed a complex with p53 and MDM2 to promote the degradation of p53. AJUBA overexpression reduced the sensitivity of cancer cells to chemotherapeutic drugs and vice versa. In addition, chemotherapeutic drugs significantly induced AJUBA expression, which was largely dependent on the presence of p53. Therefore, Ajuba formed a negative feedback loop to regulate p53 expression and activity. In conclusion, as a novel p53 negative regulator, Ajuba inhibits the apoptosis of CRC cells induced by chemotherapeutic drugs and it may be a new therapeutic target for CRC treatment.
    Keywords:  Ajuba; apoptosis; chemoresistance; colorectal cancer; p53
    DOI:  https://doi.org/10.1002/1878-0261.13421