The MYC oncoprotein is activated in a broad spectrum of human malignancies and transcriptionally reprograms the genome to drive cancer cell growth. Given this, it is unclear if targeting a single ...effector of MYC will have therapeutic benefit. MYC activates the polyamine-hypusine circuit, which posttranslationally modifies the eukaryotic translation factor eIF5A. The roles of this circuit in cancer are unclear. Here we report essential intrinsic roles for hypusinated eIF5A in the development and maintenance of MYC-driven lymphoma, where the loss of eIF5A hypusination abolishes malignant transformation of MYC-overexpressing B cells. Mechanistically, integrating RNA sequencing, ribosome sequencing, and proteomic analyses revealed that efficient translation of select targets is dependent upon eIF5A hypusination, including regulators of G1-S phase cell-cycle progression and DNA replication. This circuit thus controls MYC's proliferative response, and it is also activated across multiple malignancies. These findings suggest the hypusine circuit as a therapeutic target for several human tumor types.
Elevated EIF5A and the polyamine-hypusine circuit are manifest in many malignancies, including MYC-driven tumors, and eIF5A hypusination is necessary for MYC proliferative signaling. Not-ably, this circuit controls an oncogenic translational program essential for the development and maintenance of MYC-driven lymphoma, supporting this axis as a target for cancer prevention and treatment. See related commentary by Wilson and Klein, p. 248. This article is highlighted in the In This Issue feature, p. 247.
Chronic T-cell receptor (TCR) signaling in the tumor microenvironment is known to promote T-cell dysfunction. However, we reasoned that poorly immunogenic tumors may also compromise T cells by ...impairing their metabolism. To address this, we assessed temporal changes in T-cell metabolism, fate, and function in models of B-cell lymphoma driven by Myc, a promoter of energetics and repressor of immunogenicity. Increases in lymphoma burden most significantly impaired CD4+ T-cell function and promoted regulatory T cell (Treg) and Th1-cell differentiation. Metabolomic analyses revealed early reprogramming of CD4+ T-cell metabolism, reduced glucose uptake, and impaired mitochondrial function, which preceded changes in T-cell fate. In contrast, B-cell lymphoma metabolism remained robust during tumor progression. Finally, mitochondrial functions were impaired in CD4+ and CD8+ T cells in lymphoma-transplanted OT-II and OT-I transgenic mice, respectively. These findings support a model, whereby early, TCR-independent, metabolic interactions with developing lymphomas limits T cell-mediated immune surveillance.
The malignant transformation of normal cells is caused in part by aberrant gene expression disrupting the regulation of cell proliferation, apoptosis, senescence and DNA repair. Evidence suggests ...that the Bcl-2 antagonist of cell death (BAD)-mediated apoptotic pathway influences cancer chemoresistance. In the present study, we explored the role of the BAD-mediated apoptotic pathway in the development and progression of cancer. Using principal component analysis to derive a numeric score representing pathway expression, we evaluated clinico-genomic datasets (n=427) from corresponding normal, pre-invasive and invasive cancers of different types, such as ovarian, endometrial, breast and colon cancers in order to determine the associations between the BAD-mediated apoptotic pathway and cancer development. Immunofluorescence was used to compare the expression levels of phosphorylated BAD pBAD (serine-112, -136 and -155) in immortalized normal and invasive ovarian, colon and breast cancer cells. The expression of the BAD-mediated apoptotic pathway phosphatase, PP2C, was evaluated by RT-qPCR in the normal and ovarian cancer tissue samples. The growth-promoting effects of pBAD protein levels in the immortalized normal and cancer cells were assessed using siRNA depletion experiments with MTS assays. The expression of the BAD-mediated apoptotic pathway was associated with the development and/or progression of ovarian (n=106, p<0.001), breast (n=185, p<0.0008; n=61, p=0.04), colon (n=22, p<0.001) and endometrial (n=33, p<0.001) cancers, as well as with ovarian endometriosis (n=20, p<0.001). Higher pBAD protein levels were observed in the cancer cells compared to the immortalized normal cells, whereas PP2C gene expression was lower in the cancer compared to the ovarian tumor tissue samples (n=76, p<0.001). The increased pBAD protein levels after the depletion of PP2C conferred a growth advantage to the immortalized normal and cancer cells. The BAD-mediated apoptotic pathway is thus associated with the development of human cancers likely influenced by the protein levels of pBAD.
Abstract Objectives Ovarian cancer (OVCA) is the leading cause of mortality among women with gynecologic malignancy, in part due to the development of chemoresistance. We sought to identify ...micro-RNAs (miRNAs) associated with in vitro development of OVCA chemoresistance that may also represent potential targets for therapy. Methods In this study, four OVCA cell lines (A2780CP, A2780S, IGROV1, and OVCAR5) were serially treated with cisplatin in parallel with measurements of miRNA expression changes. Results Nine miRNAs were found to be associated with increasing cisplatin resistance (IC50 ) ( p < 0.01); however, only 5 of these miRNAs have publically available information. Pathway analysis identified 15 molecular signaling pathways that were represented by genes predicted to be targets of the 5 miRNAs (false discovery rate < 0.05), 11 of which are associated with the epithelial–mesenchymal transition (EMT). Further analysis identified 2 of those pathways as being associated with overall survival in 218 patients with OVCA. Conclusions Collectively, this panel of miRNAs associated with in vitro evolution of OVCA cisplatin resistance and the pathways identified to be associated with EMT and overall patient survival provide a framework for further investigations into EMT as a therapeutic target in patients with OVCA.
Excessive alcohol intake is a well-known modifiable risk factor for many cancers. It is still unclear whether genetic variants or single nucleotide polymorphisms (SNPs) can modify alcohol intake's ...impact on prostate cancer (PCa) aggressiveness. The objective is to test the alcohol-SNP interactions of the 7501 SNPs in the four pathways (angiogenesis, mitochondria, miRNA, and androgen metabolism-related pathways) associated with PCa aggressiveness. We evaluated the impacts of three excessive alcohol intake behaviors in 3306 PCa patients with European ancestry from the PCa Consortium. We tested the alcohol-SNP interactions using logistic models with the discovery-validation study design. All three excessive alcohol intake behaviors were not significantly associated with PCa aggressiveness. However, the interactions of excessive alcohol intake and three SNPs (rs13107662
,
= 6.2 × 10
, rs9907521
= 7.1 × 10
, and rs11925452
= 8.2 × 10
) were significantly associated with PCa aggressiveness. These alcohol-SNP interactions revealed contrasting effects of excessive alcohol intake on PCa aggressiveness according to the genotypes in the identified SNPs. We identified PCa patients with the rs13107662 (
) AA genotype, the rs11925452 (
) AA genotype, and the rs9907521 (
AG genotype were more vulnerable to excessive alcohol intake for developing aggressive PCa. Our findings support that the impact of excessive alcohol intake on PCa aggressiveness was varied by the selected genetic profiles.
Objective The objective of the study was to evaluate the biological validity of ovarian cancer (OVCA) screening and early detection efforts and to characterize signaling pathways associated with ...human cancer metastasis and patient survival. Study Design Using genome-wide expression profiling and deoxyribonucleic acid sequencing, we compared pelvic and matched extrapelvic implants from 30 patients with advanced-stage OVCA for expression of molecular signaling pathways and p53 gene mutations. Differentially expressed pathways were further evaluated in a series of primary or early-stage vs metastatic or recurrent cancer samples from 389 ovarian, prostate, and oral cancer patients. Metastasis pathways were also evaluated for associations with survival in 9 independent clinicogenomic datasets from 1691 ovarian, breast, colon, brain, and lung cancer and leukemia patients. The inhibitory effects of 1 pathway (transforming growth factor TGF-WNT) on in vitro OVCA cell migration were studied. Results Pelvic and extrapelvic OVCA implants demonstrated similar patterns of signaling pathway expression and identical p53 mutations. However, we identified 3 molecular pathways/cellular processes that were differentially expressed between pelvic and extrapelvic OVCA samples and between primary/early-stage and metastatic/advanced or recurrent ovarian, oral, and prostate cancers. Furthermore, their expression was associated with overall survival from ovarian cancer ( P = .006), colon cancer (1 pathway at P = .005), and leukemia ( P = .05). Artesunate-induced TGF-WNT pathway inhibition impaired OVCA cell migration. Conclusion Advanced-stage OVCA has a unifocal origin in the pelvis. Molecular pathways associated with extrapelvic OVCA spread are also associated with metastasis from other human cancers and with overall patient survival. Such pathways represent appealing therapeutic targets for patients with metastatic disease.
Prostate cancer (PCa) tumors harboring translocations of ETS family genes with the androgen responsive TMPRSS2 gene (ETS+ tumors) provide a robust biomarker for detecting PCa in approximately 70% of ...patients. ETS+ PCa express high levels of the androgen receptor (AR), yet PCa tumors lacking ETS fusions (ETS-) also express AR and demonstrate androgen-regulated growth. In this study, we evaluate the differences in the AR-regulated transcriptomes between ETS+ and ETS- PCa tumors.
10,608 patient tumors from three independent PCa datasets classified as ETS+ (samples overexpressing ERG or other ETS family members) or ETS- (all other PCa) were analyzed for differential gene expression using false-discovery-rate adjusted methods and gene-set enrichment analysis (GSEA).
Based on the expression of AR-dependent genes and an unsupervised Principal Component Analysis (PCA) model, AR-regulated gene expression alone was able to separate PCa samples into groups based on ETS status in all PCa databases. ETS status distinguished several differentially expressed genes in both TCGA (6.9%) and GRID (6.6%) databases, with 413 genes overlapping in both databases. Importantly, GSEA showed enrichment of distinct androgen-responsive genes in both ETS- and ETS+ tumors, and AR ChIP-seq data identified 131 direct AR-target genes that are regulated in an ETS-specific fashion. Notably, dysregulation of ETS-dependent AR-target genes within the metabolic and non-canonical WNT pathways was associated with clinical outcomes.
ETS status influences the transcriptional repertoire of the AR, and ETS- PCa tumors appear to rely on distinctly different AR-dependent transcriptional programs to drive and sustain tumorigenesis.
While mutations in the KRAS oncogene are among the most prevalent in human cancer, there are few successful treatments to target these tumors. It is also likely that heterogeneity in KRAS-mutant ...tumor biology significantly contributes to the response to therapy. We hypothesized that the presence of commonly co-occurring mutations in STK11 and TP53 tumor suppressors may represent a significant source of heterogeneity in KRAS-mutant tumors. To address this, we utilized a large cohort of resected tumors from 442 lung adenocarcinoma patients with data including annotation of prevalent driver mutations (KRAS and EGFR) and tumor suppressor mutations (STK11 and TP53), microarray-based gene expression and clinical covariates, including overall survival (OS). Specifically, we determined impact of STK11 and TP53 mutations on a new KRAS mutation-associated gene expression signature as well as previously defined signatures of tumor cell proliferation and immune surveillance responses. Interestingly, STK11, but not TP53 mutations, were associated with highly elevated expression of KRAS mutation-associated genes. Mutations in TP53 and STK11 also impacted tumor biology regardless of KRAS status, with TP53 strongly associated with enhanced proliferation and STK11 with suppression of immune surveillance. These findings illustrate the remarkably distinct ways through which tumor suppressor mutations may contribute to heterogeneity in KRAS-mutant tumor biology. In addition, these studies point to novel associations between gene mutations and immune surveillance that could impact the response to immunotherapy.
Tristetraprolin (TTP) is an RNA-binding protein that post-transcriptionally suppresses gene expression by delivering mRNA cargo to processing bodies (P-bodies) where the mRNA is degraded. TTP ...functions as a tumor suppressor in a mouse model of B cell lymphoma, and in some human malignancies low TTP expression correlates with reduced survival. Here we report important prognostic and functional roles for TTP in human prostate cancer. First, gene expression analysis of prostate tumors revealed low TTP expression correlates with patients having high-risk Gleason scores and increased biochemical recurrence. Second, in prostate cancer cells with low levels of endogenous TTP, inducible TTP expression inhibits their growth and proliferation, as well as their clonogenic growth. Third, TTP functions as a tumor suppressor in prostate cancer, as forced TTP expression markedly impairs the tumorigenic potential of prostate cancer cells in a mouse xenograft model. Finally, pathway analysis of gene expression data suggested metabolism is altered by TTP expression in prostate tumor cells, and metabolic analyses revealed that such processes are impaired by TTP, including mitochondrial respiration. Collectively, these findings suggest that TTP is an important prognostic indicator for prostate cancer, and augmenting TTP function would effectively disable the metabolism and proliferation of aggressive prostate tumors.
The advent of extensive small molecule databases has brought with it the problem of searching these repositories for entities with desired properties. A multitude of similarity-searching algorithms, ...based on different underlying methods, currently exist for this purpose. However, due to the somewhat nebulous definition of “similar”, all such approaches maintain different strengths and weaknesses. Presented here is PZIM, a new approach fundamentally based on a description of the atom environment that includes multiple adjustable features allowing for searches to be tailored on the basis of the user definition of similarity. In addition to flexible atom environment size, PZIM allows for the use of an atom-substitution matrix to identify similar pharmacophoric recognition elements. Finally, PZIM produces 2-dimensional alignments of all compared molecules that pass a user-defined threshold for similarity. To determine the usefulness of the approach, PZIM was compared to seven other similarity-searching methods on nine data sets recently published. PZIM achieved a rank of first or second in the majority of cases tested and obtained the highest average rank score across all methods tested. These results demonstrate the effectiveness of the PZIM approach across diverse search conditions.
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