A KLF6-driven transcriptional network links lipid homeostasis and tumour growth in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is characterised by frequent inactivation of the VHL tumour suppressor gene and consequent accumulation of HIF2A that drives tumourigenesis. The current clinically-approved therapies for ccRCC are those targeting the angiogenesis and mTOR signalling pathways, however, the overall patients’ objective response rates are still low, and patients rapidly develop resistance towards the administered therapies. An incomplete understanding of the underlying molecular mechanisms that support ccRCC progression has contributed to the lack of effective diagnostic and/or therapeutic strategies developed, especially for the highly mortal advanced stage ccRCC. Thus, the identification of cellular networks on which ccRCC cells are highly dependent would facilitate the development of better diagnostic and/or therapeutic approaches for ccRCC. Super enhancers have been reported to drive the expression of critical transcription regulators in various biological contexts including the regulation of cancer phenotypes. Previously generated H3K27ac ChIP-Seq data from several ccRCC cell lines has identified KLF6, a zinc finger DNA-binding transcription factor, to be associated with one of the strongest super enhancers in ccRCC, which could signify a biological relevance to KLF6 in supporting ccRCC pathogenesis. Thus, the purpose of this present study was to interrogate the role of KLF6 in ccRCC, and dissect the KLF6-regulated transcriptional networks and how they can contribute in supporting ccRCC pathogenesis. It was discovered that KLF6 expression was supported by a robust super enhancer that integrates signals from multiple pathways, including the ccRCC-initiating VHL-HIF2A pathway. In line with its regulation by the super enhancer, CRISPR-Cas9 and CRISPRi-mediated perturbation of KLF6 led to impaired ccRCC cells growth in vitro and in vivo as well as reducing the cells metastatic lung colonisation capability. KLF6 inhibition led to the deregulation of lipid homeostasis pathways in ccRCC cells. A dual KLF6 role was identified in modulating lipid homeostasis pathways in ccRCC: First, KLF6 directly regulates the expression of several important lipid homeostasis genes. Second, KLF6 promotes PDGFB expression, which activates the mTORC1 signalling pathway and the key lipid metabolism transcriptional regulators SREBF1 and SREBF2. KLF6 and mTORC1 thus co-regulate lipid homeostasis, consequently supporting ccRCC cell growth. Furthermore, findings from this study also reveal a molecular link between the PDGF and mTORC1 signalling pathways, which are the clinically relevant therapeutic targets in ccRCC. In general, the link between super enhancer-driven transcriptional networks and essential metabolic pathways described herein may provide clues to the mechanisms that maintain the stability of cell identity-defining transcriptional programmes in cancer.1.Ministry of Higher Education Malaysia 2.National University of Malaysi

Cancer Cell-Derived PDGFB Stimulates mTORC1 Activation in Renal Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a hypervascular tumor that is characterized by bi-allelic inactivation of the VHL tumor suppressor gene and mTOR signalling pathway hyperactivation. The pro-angiogenic factor PDGFB, a transcriptional target of super enhancer-driven KLF6, can activate the mTORC1 signalling pathway in ccRCC. However, the detailed mechanisms of PDGFB-mediated mTORC1 activation in ccRCC have remained elusive. Here, we investigated whether ccRCC cells are able to secrete PDGFB into the extracellular milieu and stimulate mTORC1 signalling activity. We found that ccRCC cells secreted PDGFB extracellularly, and by utilizing KLF6- and PDGFB-engineered ccRCC cells, we showed that the level of PDGFB secretion was positively correlated with the expression of intracellular KLF6 and PDGFB. Moreover, the reintroduction of either KLF6 or PDGFB was able to sustain mTORC1 signalling activity in KLF6-targeted ccRCC cells. We further demonstrated that conditioned media of PDGFB-overexpressing ccRCC cells was able to re-activate mTORC1 activity in KLF6-targeted cells. In conclusion, cancer cell-derived PDGFB can mediate mTORC1 signalling pathway activation in ccRCC, further consolidating the link between the KLF6-PDGFB axis and the mTORC1 signalling pathway activity in ccRCC

Integration of RNA-Seq and proteomics data identifies glioblastoma multiforme surfaceome signature

Background: Glioblastoma multiforme (GBM) is a highly lethal, stage IV brain tumour with a prevalence of approximately 2 per 10,000 people globally. The cell surface proteins or surfaceome serve as information gateway in many oncogenic signalling pathways and are important in modulating cancer phenotypes. Dysregulation in surfaceome expression and activity have been shown to promote tumorigenesis. The expression of GBM surfaceome is a case in point; OMICS screening in a cell-based system identified that this sub-proteome is largely perturbed in GBM. Additionally, since these cell surface proteins have ‘direct’ access to drugs, they are appealing targets for cancer therapy. However, a comprehensive GBM surfaceome landscape has not been fully defined yet. Thus, this study aimed to define GBM-associated surfaceome genes and identify key cell-surface genes that could potentially be developed as novel GBM biomarkers for therapeutic purposes. Methods: We integrated the RNA-Seq data from TCGA GBM (n = 166) and GTEx normal brain cortex (n = 408) databases to identify the significantly dysregulated surfaceome in GBM. This was followed by an integrative analysis that combines transcriptomics, proteomics and protein-protein interaction network data to prioritize the highconfidence GBM surfaceome signature. Results: Of the 2381 significantly dysregulated genes in GBM, 395 genes were classified as surfaceome. Via the integrative analysis, we identified 6 high-confidence GBM molecular signature, HLA-DRA, CD44, SLC1A5, EGFR, ITGB2, PTPRJ, which were significantly upregulated in GBM. The expression of these genes was validated in an independent transcriptomics database, which confirmed their upregulated expression in GBM. Importantly, high expression of CD44, PTPRJ and HLA-DRA is significantly associated with poor disease-free survival. Last, using the Drugbank database, we identified several clinically-approved drugs targeting the GBM molecular signature suggesting potential drug repurposing. Conclusions: In summary, we identified and highlighted the key GBM surface-enriched repertoires that could be biologically relevant in supporting GBM pathogenesis. These genes could be further interrogated experimentally in future studies that could lead to efficient diagnostic/prognostic markers or potential treatment options for GBM

mIR-99a-5p and mIR-148a-3p as candidate molecular biomarkers for the survival of lung cancer patients

MicroRNA (miRNA) has emerged as a promising biomarker for improving the current state of an early lung cancer diagnosis. Multiple studies have reported that circulating miRNAs are usually combined in a single panel to determine lung cancer risk. In this study, we sought to assess the prognostic predictive values of the potential miRNAs for lung cancer survival among Malaysian patients. The microarray analysis was performed on the isolated miRNA samples of formalin-fixed lung cancer tissues from Malaysian populations. The correlation between miRNA expression and lung adenocarcinoma (LUAD) patient survival was predicted using TGGA data, followed by extensive in silico analyses, including miRNA target gene identification, protein-protein interaction (PPI) network construction, subnetwork (SN) detection, functional enrichment analysis, gene-disease associations, and survival analysis in advanced-stage LUAD. Overall, two promising miR-99a-5p and miR-148a-3p were upregulated in the patients with good survival. We found that 64 miR-99a-5p and 95 miR-148a-3p target genes were associated with poor prognosis and highly participated in cancer-associated processes, such as apoptosis, mRNA transport and cell-cell adhesion. The density score of 4.667, 3.333, and 3.000 in respective SN1, SN2, and SN3 showed the significant subnetworks of constructed PPI leading to the identification of 17 targets, of which ~79% of them involved in neoplastic diseases. Four high-confidence target genes (SUDS3, TOMM22, KPNA4, and HMGB1) were associated with worse overall survival in LUAD patients, implying their critical roles in LUAD pathogenesis. These findings shed additional light on the roles of miR-99a-5p and miR-148a-3p as potential biomarkers for LUAD survival

The spectrum of in vitro maturation in clinical practice: the current insight

In vitro oocyte maturation (IVM) has been used worldwide. Despite the long-term implementation, the uptake of this procedure to complement current in vitro fertilization (IVF) remains low. The main reason is likely due to the non-synchronization of protocol and definition criteria, leading to difficulty in collective proper outcome data worldwide and, thus, lack of understanding of the exact IVM procedure. The review aims to consolidate the current clinical practice of IVM by dissecting relevant publications to be tailored for a current spectrum of clinical practice. Nevertheless, the background theories of oocyte maturation were also explored to provide a comprehensive understanding of the basis of IVM theories. Additional discussion of other potential uses of IVM in the future, such as in ovarian tissue cryopreservation known as OTO-IVM for fertility preservation and among women with diminished ovarian reserve, was also explored. Otherwise, future collaboration among all IVM centers is paramount for better collection of clinical data to provide valid recommendations for IVM in clinical practice, especially in molecular integrity and possible DNA alteration if present for IVM offspring outcome safety purposes

Identification of missense mutations in genes related to cancer pathways in glioma

Glioma is the most common primary brain tumour of the central nervous system. Many genetic alterations and mutations have been identified in glioma using various approaches. We performed DNA sequencing on the tumours of 16 patients with Grade I, II, III and IV glioma. The AmpliSeq Cancer Primers Pool was used to generate the amplicons. The targeted-ion sphere particles were prepared using the Ion One Touch and Ion Enrichment systems. DNA sequencing was performed on the Ion Torrent Personal Genome Machine (PGM) and the data were analysed using the Torrent Suite Software. In total, 14 mutations were identified in the following genes: KDR (Q472H), MLH1 (V384D), MET (N375S), PTPN11 (E69K), BRAF (V600E), TP53 (D149E, E154K, V157F), IDH1 (R132H), PIK3CA (H1047R), CSF1R (c1061_1061 ins A), KIT (M541L), PTEN (c1373_1373 del A) and PDGFRA (E556V). In addition, there were four novel mutations identified; TP53 (E154K, and D149E), CSF1R (c1061_1061 ins A) and PDGFRA (E556V). The pathogenicity prediction showed that only three mutations were pathogenic: PTPN11 (E69K), BRAF (V600E) and Tp53 (E154K). These mutations result in changes of the proteins’ structure and could affect their functions. Pathway analyses suggested that these genes are closely related to the pathogenesis of GBM through several pathways such as proliferation and invasion, metabolism and angiogenesis. In conclusion, PGM in combination with the AmpliSeq Cancer Panel could be utilised as a potential molecular diagnostic tool not only for glioma but also for other cancers

Impact of the Cancer Cell Secretome in Driving Breast Cancer Progression

Breast cancer is a complex and heterogeneous disease resulting from the accumulation of genetic and epigenetic alterations in breast epithelial cells. Despite remarkable progress in diagnosis and treatment, breast cancer continues to be the most prevalent cancer affecting women worldwide. Recent research has uncovered a compelling link between breast cancer onset and the extracellular environment enveloping tumor cells. The complex network of proteins secreted by cancer cells and other cellular components within the tumor microenvironment has emerged as a critical player in driving the disease’s metastatic properties. Specifically, the proteins released by the tumor cells termed the secretome, can significantly influence the progression and metastasis of breast cancer. The breast cancer cell secretome promotes tumorigenesis through its ability to modulate growth-associated signaling pathways, reshaping the tumor microenvironment, supporting pre-metastatic niche formation, and facilitating immunosurveillance evasion. Additionally, the secretome has been shown to play a crucial role in drug resistance development, making it an attractive target for cancer therapy. Understanding the intricate role of the cancer cell secretome in breast cancer progression will provide new insights into the underlying mechanisms of this disease and aid in the development of more innovative therapeutic interventions. Hence, this review provides a nuanced analysis of the impact of the cancer cell secretome on breast cancer progression, elucidates the complex reciprocal interaction with the components of the tumor microenvironment and highlights emerging therapeutic opportunities for targeting the constituents of the secretome

CD44: A multifunctional mediator of cancer progression

CD44, a non-kinase cell surface transmembrane glycoprotein, has been widely implicated as a cancer stem cell (CSC) marker in several cancers. Cells overexpressing CD44 possess several CSC traits, such as self-renewal and epithelial-mesenchymal transition (EMT) capability, as well as a resistance to chemo- and radiotherapy. The CD44 gene regularly undergoes alternative splicing, resulting in the standard (CD44s) and variant (CD44v) isoforms. The interaction of such isoforms with ligands, particularly hyaluronic acid (HA), osteopontin (OPN) and matrix metalloproteinases (MMPs), drive numerous cancer-associated signalling. However, there are contradictory results regarding whether high or low CD44 expression is associated with worsening clinicopathological features, such as a higher tumour histological grade, advanced tumour stage and poorer survival rates. Nonetheless, high CD44 expression significantly contributes to enhanced tumourigenic mechanisms, such as cell proliferation, metastasis, invasion, migration and stemness; hence, CD44 is an important clinical target. This review summarises current research regarding the different CD44 isoform structures and their roles and functions in supporting tumourigenesis and discusses CD44 expression regulation, CD44-signalling pathways and interactions involved in cancer development. The clinical significance and prognostic value of CD44 and the potential of CD44 as a therapeutic target in cancer are also addressed

Cancer Cell-Derived PDGFB Stimulates mTORC1 Activation in Renal Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a hypervascular tumor that is characterized by bi-allelic inactivation of the VHL tumor suppressor gene and mTOR signalling pathway hyperactivation. The pro-angiogenic factor PDGFB, a transcriptional target of super enhancer-driven KLF6, can activate the mTORC1 signalling pathway in ccRCC. However, the detailed mechanisms of PDGFB-mediated mTORC1 activation in ccRCC have remained elusive. Here, we investigated whether ccRCC cells are able to secrete PDGFB into the extracellular milieu and stimulate mTORC1 signalling activity. We found that ccRCC cells secreted PDGFB extracellularly, and by utilizing KLF6- and PDGFB-engineered ccRCC cells, we showed that the level of PDGFB secretion was positively correlated with the expression of intracellular KLF6 and PDGFB. Moreover, the reintroduction of either KLF6 or PDGFB was able to sustain mTORC1 signalling activity in KLF6-targeted ccRCC cells. We further demonstrated that conditioned media of PDGFB-overexpressing ccRCC cells was able to re-activate mTORC1 activity in KLF6-targeted cells. In conclusion, cancer cell-derived PDGFB can mediate mTORC1 signalling pathway activation in ccRCC, further consolidating the link between the KLF6-PDGFB axis and the mTORC1 signalling pathway activity in ccRCC

Epigenome-wide DNA methylation profiling in colorectal cancer and normal adjacent colon using Infinium Human Methylation 450K

The aims were to profile the DNA methylation in colorectal cancer (CRC) and to explore cancer-specific methylation biomarkers. Fifty-four pairs of CRCs and the adjacent normal tissues were subjected to Infinium Human Methylation 450K assay and analysed using ChAMP R package. A total of 26,093 differentially methylated probes were identified, which represent 6156 genes; 650 probes were hypermethylated, and 25,443 were hypomethylated. Hypermethylated sites were common in CpG islands, while hypomethylated sites were in open sea. Most of the hypermethylated genes were associated with pathways in cancer, while the hypomethylated genes were involved in the PI3K-AKT signalling pathway. Among the identified differentially methylated probes, we found evidence of four potential probes in CRCs versus adjacent normal; HOXA2 cg06786372, OPLAH cg17301223, cg15638338, and TRIM31 cg02583465 that could serve as a new biomarker in CRC since these probes were aberrantly methylated in CRC as well as involved in the progression of CRC. Furthermore, we revealed the potential of promoter methylation ADHFE1 cg18065361 in differentiating the CRC from normal colonic tissue from the integrated analysis. In conclusion, aberrant DNA methylation is significantly involved in CRC pathogenesis and is associated with gene silencing. This study reports several potential important methylated genes in CRC and, therefore, merit further validation as novel candidate biomarker genes in CRC