CCRL2 affects the sensitivity of myelodysplastic syndrome and secondary acute myeloid leukemia cells to azacitidine.

Better understanding of the biology of resistance to DNA methyltransferase (DNMT) inhibitors is required to identify therapies that can improve their efficacy for patients with high-risk myelodysplastic syndrome (MDS). CCRL2 is an atypical chemokine receptor that is upregulated in CD34+ cells from MDS patients and induces proliferation of MDS and secondary acute myeloid leukemia (sAML) cells. In this study, we evaluated any role that CCRL2 may have in the regulation of pathways associated with poor response or resistance to DNMT inhibitors. We found that CCRL2 knockdown in TF-1 cells downregulated DNA methylation and PRC2 activity pathways and increased DNMT suppression by azacitidine in MDS/sAML cell lines (MDS92, MDS-L and TF-1). Consistently, CCRL2 deletion increased the sensitivity of these cells to azacitidine in vitro and the efficacy of azacitidine in an MDS-L xenograft model. Furthermore, CCRL2 overexpression in MDS-L and TF-1 cells decreased their sensitivity to azacitidine. Finally, CCRL2 levels were higher in CD34+ cells from MDS and MDS/myeloproliferative neoplasm patients with poor response to DNMT inhibitors. In conclusion, we demonstrated that CCRL2 modulates epigenetic regulatory pathways, particularly DNMT levels, and affects the sensitivity of MDS/sAML cells to azacitidine. These results support CCRL2 targeting as having therapeutic potential in MDS/sAML.

The role of the atypical chemokine receptor CCRL2 in myelodysplastic syndrome and secondary acute myeloid leukemia.

The identification of new pathways supporting the myelodysplastic syndrome (MDS) primitive cells growth is required to develop targeted therapies. Within myeloid malignancies, men have worse outcomes than women, suggesting male sex hormone-driven effects in malignant hematopoiesis. Androgen receptor promotes the expression of five granulocyte colony-stimulating factor receptor-regulated genes. Among them, CCRL2 encodes an atypical chemokine receptor regulating cytokine signaling in granulocytes, but its role in myeloid malignancies is unknown. Our study revealed that CCRL2 is up-regulated in primitive cells from patients with MDS and secondary acute myeloid leukemia (sAML). CCRL2 knockdown suppressed MDS92 and MDS-L cell growth and clonogenicity in vitro and in vivo and decreased JAK2/STAT3/STAT5 phosphorylation. CCRL2 coprecipitated with JAK2 and potentiated JAK2-STAT interaction. Erythroleukemia cells expressing JAK2V617F showed less effect of CCRL2 knockdown, whereas fedratinib potentiated the CCRL2 knockdown effect. Conclusively, our results implicate CCRL2 as an MDS/sAML cell growth mediator, partially through JAK2/STAT signaling.

Genome annotation by shotgun inactivation of a native gene in hemizygous cells: application to BRCA2 with implication of hypomorphic variants.

The greatest interpretive challenge of modern medicine may be to functionally annotate the vast variation of human genomes. Demonstrating a proposed approach, we created a library of BRCA2 exon 27 shotgun-mutant plasmids including solitary and multiplex mutations to generate human knockin clones using homologous recombination. This 55-mutation, 13-clone syngeneic variance library (SyVaL) comprised severely affected clones having early-stop nonsense mutations, functionally hypomorphic clones having multiple missense mutations emphasizing the potential to identify and assess hypomorphic mutations in novel proteomic and epidemiologic studies, and neutral clones having multiple missense mutations. Efficient coverage of nonessential amino acids was provided by mutation multiplexing. Severe mutations were distinguished from hypomorphic or neutral changes by chemosensitivity assays (hypersensitivity to mitomycin C and acetaldehyde), by analysis of RAD51 focus formation, and by mitotic multipolarity. A multiplex unbiased approach of generating all-human SyVaLs in medically important genes, with random mutations in native genes, would provide databases of variants that could be functionally annotated without concerns arising from exogenous cDNA constructs or interspecies interactions, as a basis for subsequent proteomic domain mapping or clinical calibration if desired. Such gene-irrelevant approaches could be scaled up for multiple genes of clinical interest, providing distributable cellular libraries linked to public-shared functional databases.

Hypersensitivities for acetaldehyde and other agents among cancer cells null for clinically relevant Fanconi anemia genes.

Large-magnitude numerical distinctions (>10-fold) among drug responses of genetically contrasting cancers were crucial for guiding the development of some targeted therapies. Similar strategies brought epidemiological clues and prevention goals for genetic diseases. Such numerical guides, however, were incomplete or low magnitude for Fanconi anemia pathway (FANC) gene mutations relevant to cancer in FANC-mutation carriers (heterozygotes). We generated a four-gene FANC-null cancer panel, including the engineering of new PALB2/FANCN-null cancer cells by homologous recombination. A characteristic matching of FANCC-null, FANCG-null, BRCA2/FANCD1-null, and PALB2/FANCN-null phenotypes was confirmed by uniform tumor regression on single-dose cross-linker therapy in mice and by shared chemical hypersensitivities to various inter-strand cross-linking agents and γ-radiation in vitro. Some compounds, however, had contrasting magnitudes of sensitivity; a strikingly high (19- to 22-fold) hypersensitivity was seen among PALB2-null and BRCA2-null cells for the ethanol metabolite, acetaldehyde, associated with widespread chromosomal breakage at a concentration not producing breaks in parental cells. Because FANC-defective cancer cells can share or differ in their chemical sensitivities, patterns of selective hypersensitivity hold implications for the evolutionary understanding of this pathway. Clinical decisions for cancer-relevant prevention and management of FANC-mutation carriers could be modified by expanded studies of high-magnitude sensitivities.

Targeted deletion of Jun/AP-1 in alveolar epithelial cells causes progressive emphysema and worsens cigarette smoke-induced lung inflammation.

Chronic obstructive pulmonary disease appears to occur slowly and progressively over many years, with both genetic factors and environmental modifiers contributing to its pathogenesis. Although the c-Jun/activator protein 1 transcriptional factor regulates cell proliferation, apoptosis, and inflammatory responses, its role in lung pathogenesis is largely unknown. In this study, we report decreased expression levels of c-Jun mRNA and protein in the lung tissues of patients with advanced chronic obstructive pulmonary disease, and the genetic deletion of c-Jun specifically in alveolar epithelial cells causes progressive emphysema with lung inflammation and alveolar air space enlargement, which are cardinal features of emphysema. Although mice lacking c-Jun specifically in lung alveolar epithelial cells appear normal at the age of 6 weeks, when exposed to long-term cigarette smoke, c-Jun-mutant mice display more lung inflammation with perivascular and peribronchiolar infiltrates compared with controls. These results demonstrate that the c-Jun/activator protein 1 pathway is critical for maintaining lung alveolar cell homeostasis and that loss of its expression can contribute to lung inflammation and progressive emphysema.

Structural analysis of the cancer-specific promoter in mesothelin and in other genes overexpressed in cancers.

Mesothelin (MSLN) may be the most "dramatic" of the tumor markers, being strongly overexpressed in nearly one-third of human malignancies. The biochemical cause is unclear. We previously ascribed this cancer-specific overexpression to an element, Canscript, residing around 50 bp 5' of the transcription start site in cancer (Hucl, T., Brody, J. R., Gallmeier, E., Iacobuzio-Donahue, C. A., Farrance, I. K., and Kern, S. E. (2007) Cancer Res. 67, 9055-9065). Herein, we found a Canscript promoter activity elevated over 100-fold in cancer cells. In addition to a highly conserved TEAD1 (TEA domain family member 1)-binding MCAT motif, nucleotide substitution revealed the consensus core sequence (WCYCCACCC) of an SP1-like motif in Canscript. The unknown transcription factor binding to the SP1-like motif may hold the key for the cancer specificity of Canscript. SP1, GLI1, and RUNX1, -2, and -3 appeared unlikely to be the direct transcription factors acting at the SP1-like motif, but KLF6 had some features of such a candidate. YAP1, a TEAD1-binding protein, appeared necessary, but not sufficient, for Canscript activity; knockdown of YAP1 by small interfering RNAs greatly reduced MSLN levels in MSLN-overexpressing cells, but overexpressing YAP1 in MSLN-negative cells did not induce MSLN expression. Cansript-like sequences were found in other genes up-regulated in pancreatic cancer; reporters driven by the sequences from FXYD3, MUC1, and TIMP1 had activities more than 2 times that of the control. This suggested that the cause of MSLN overexpression might also contribute mechanistically to the overexpression of other tumor markers.

Polo-like kinase 1 regulates cell proliferation and is targeted by miR-593* in esophageal cancer.

Polo-like kinase 1 (PLK1) is overexpressed in various human cancers. However, the biological functions and the post-transcriptional regulations of PLK1 in esophageal cancer (EC) are still unknown. The purposes of our study are to determine whether PLK1 can be a molecular target of EC therapy and to identify a microRNA (miRNA) targeting PLK1. We performed loss-of-function and gain-of-function experiments regarding cell proliferation, cell cycle, apoptosis, in vivo tumor formation and luciferase reporter assays, using siRNAs against PLK1 and miRNA. PLK1 protein was expressed in all 11 EC cell lines, but not in normal esophageal epithelial cells (HEEpiC). Knockdown of PLK1 in EC cells induced G2/M arrest (p < 0.001) in cell cycle assay and reduced cell proliferation (p = 0.019) and tumor formation ability in vivo (p < 0.0001). MiR-593*, identified as a miRNA targeting PLK1 by a database search, was less expressed especially in six EC cell lines than HEEpiC cells. Moreover, miR-593* expression level was inversely correlated with PLK1 mRNA level in 48 clinical tissue specimens of EC (p = 0.006). Introduction of synthetic miR-593* suppressed PLK1 expression by 69-73%, reduced cell proliferation (p = 0.008) and increased cell proportion of G2/M phase (p = 0.01) in HSA/c (an EC cells), whereas a miR-593* inhibitor upregulated PLK1 expression by 11-55%. Additionally, luciferase assay demonstrated that miR-593* interacted two binding sites in the PLK1 3'-UTR and reduced 56.8-71.5% of luciferase activity by degrading luciferase mRNA in HSA/c cells. In conclusion, PLK1 is post-transcriptionally regulated by miR-593* and could be a promising molecular target for EC treatment.

Relation between normal rectal methylation, smoking status, and the presence or absence of colorectal adenomas.

BACKGROUND: Colorectal cancer (CRC) is 1 of the leading causes of death in the Western world. CRC develops from premalignant lesions, chiefly colorectal adenomas. Currently, the most accurate and recommended screening method for finding colorectal adenomas is colonoscopy performed on all individuals aged>50 years. However, the costs and risks associated with this procedure are relatively high. The objectives of the current study were to correlate epigenetic alterations that occur in normal rectal mucosa, smoking status, and age with the presence or absence of concomitant colorectal adenomas and to assess the potential clinical value of methylation in normal rectal biopsies as a screening assay for the presence of polyps and, hence, the need for a full colonoscopy. METHODS: One hundred thirteen normal rectal mucosal biopsies from 113 patients were studied. DNA was extracted, modified with sodium bisulfite, and subjected to real-time quantitative, methylation-specific polymerase chain reaction analysis for the following genes: adenomatous polyposis coli (APC); cadherin 1, type 1, E-cadherin (epithelial) (CDH1); estrogen receptor 1 (ESR1); cytokine high in normal 1 (HIN1); hyperplastic polyposis protein 1 (HPP1); O-6 methylguanine-DNA methyltransferase (MGMT); neural epidermal growth factor-like 1 (NELL1); splicing factor 3B, 14-kDa subunit (p14); cyclin-dependent kinase (CDK) inhibitor 2B (inhibits CDK4) (p15); retinoic acid receptor beta (RARß); somatostatin (SST); tachykinin, precursor 1 (TAC1); and tissue inhibitor of metalloproteinase (TIMP) metallopeptidase inhibitor 3 (TIMP3). Data were then analyzed using several proprietary software programs. RESULTS: By using several sets of genes, clinical characteristics, and multivariate analyses, the authors developed a prediction model for the presence of concomitant colorectal adenomas at the time of rectal biopsy. They also observed strong correlations between smoking status and rectal methylation pattern and between smoking status and the presence or risk of concomitant adenomas. CONCLUSIONS: A prediction model was developed for the presence of colorectal adenomas based on gene methylation patterns in the normal rectum. The results indicated that these genes may be involved in early stages of adenoma formation. The observed epigenetic alterations in these markers may be caused in part by the effects of smoking and/or age. Normal rectal methylation may be useful as a biomarker for narrowing the population in need of screening colonoscopy.

Postoperative complications following surgery for rectal cancer.

OBJECTIVE: This systematic review was designed to determine postoperative complication rates of radical surgery for rectal cancer (abdominal perineal resection and anterior resection). SUMMARY OF BACKGROUND DATA: Lack of accepted complication rates for rectal cancer surgery may hinder quality improvement efforts and may impede the conception of future studies because of uncertainty regarding the expected event rates. METHODS: All prospective studies of rectal cancer receiving radical surgery published between 1990 and August 2008 were obtained by searching Ovid MEDLINE, EMBASE, as well as ASCO GI, CAGS, and ASCRS meeting abstracts between 2004 and 2008. There was no language restriction. The outcomes extracted were anastomotic leak, pelvic sepsis, postoperative death, wound infection, and fecal incontinence. Summary complication rates were obtained using a random effects model; the Z-test was used to test for study heterogeneity. RESULTS: Fifty-three prospective cohort studies and 45 randomized controlled studies with 36,315 patients (24,845 patients had an anastomosis) were eligible for inclusion. Most of the studies found were based in continental Europe (58%), followed by Asia (25%), United Kingdom (10%), North America (5%), and Australia/New Zealand. The anastomotic leak rate, reported in 84 studies, was 11% (95% CI: 10, 12); the pelvic sepsis rate, in 29 studies, was 12% (9, 16); the postoperative death rate, in 75 studies, was 2% (2, 3); and the wound infection rate, in 50 studies, was 7% (5, 8). Fecal incontinence rates were reported in too few studies and so heterogeneously that numerical summarization was inappropriate. Year of publication, use of preoperative radiation, use of laparoscopy, and use of protecting stoma were not significant variables, but average age, median tumor height, and method of detection (clinical vs. radiologic) showed significance to explain heterogeneity in anastomotic leak rates. Year of publication, study origin, average age, and use of laparoscopy were significant, but median tumor height and preoperative radiation use were not significant in explaining heterogeneity among observed postoperative death rates. With multivariable analysis, only average age for anastomotic leak and year of publication for postoperative death remained significant. CONCLUSIONS: Benchmark complication rates for radical rectal cancer surgery were obtained for use in sample size calculations in future studies and for quality control purposes. Postoperative death rates showed improvement in recent years.

Screening for microsatellite instability identifies frequent 3'-untranslated region mutation of the RB1-inducible coiled-coil 1 gene in colon tumors.

BACKGROUND: Coding region microsatellite instability (MSI) results in loss of gene products and promotion of microsatellite-unstable (MSI-H) carcinogenesis. Recent studies have indicated that MSI within 3'-untranslated regions (3'UTRs) may post-transcriptionally dysregulate gene products. Within this context, we conducted a broad mutational survey of 42 short 3'UTR microsatellites (MSs) in 45 MSI-H colorectal tumors and their corresponding normal colonic mucosae. METHODOLOGY/PRINCIPAL FINDINGS: In order to estimate the overall susceptibility of MSs to MSI in MSI-H tumors, the observed MSI frequency of each MS was correlated with its length, interspecies sequence conservation level, and distance from some genetic elements (i.e., stop codon, polyA signal, and microRNA binding sites). All MSs were stable in normal colonic mucosae. The MSI frequency at each MS in MSI-H tumors was independent of sequence conservation level and distance from other genetic elements. In contrast, MS length correlated significantly with MSI frequency in MSI-H tumors (r=0.86, p=7.2x10(-13)). 3'UTR MSs demonstrated MSI frequencies in MSI-H tumors higher than the 99% upper limit predicted by MS length for RB1-inducible coiled-coil 1(RB1CC1, mutation frequency 68.4%), NUAK family SNF1-like kinase 1(NUAK1, 31.0%), and Rtf1, Paf1/RNA polymerase II complex component, homolog (RTF1, 25.0%). An in silico prediction of RNA structure alterations was conducted for these MSI events to gauge their likelihood of affecting post-transcriptional regulation. RB1CC1 mutant was predicted to lose a microRNA-accessible loop structure at a putative binding site for the tumor-suppressive microRNA, miR-138. In contrast, the predicted 3'UTR structural change was minimal for NUAK1- and RTF1 mutants. Notably, real-time quantitative RT-PCR analysis revealed significant RB1CC1 mRNA overexpression vs. normal colonic mucosae in MSI-H cancers manifesting RB1CC1 3'UTR MSI (9.0-fold; p = 3.6x10(-4)). CONCLUSIONS: This mutational survey of well-characterized short 3'UTR MSs confirms that MSI incidence in MSI-H colorectal tumors correlates with MS length, but not with sequence conservation level or distance from other genetic elements. This study also identifies RB1CC1 as a novel target of frequent mutation and aberrant upregulation in MSI-H colorectal tumors. The predicted loss of a microRNA-accessible structure in mutant RB1CC1 RNA fits the hypothesis that 3'UTR MSI involves in aberrant RB1CC1 posttranscriptional upregulation. Further direct assessments are indicated to investigate this possibility.

A multicenter, double-blinded validation study of methylation biomarkers for progression prediction in Barrett's esophagus.

Esophageal adenocarcinoma risk in Barrett's esophagus (BE) is increased 30- to 125-fold versus the general population. Among all BE patients, however, neoplastic progression occurs only once per 200 patient-years. Molecular biomarkers are therefore needed to risk-stratify patients for more efficient surveillance endoscopy and to improve the early detection of progression. We therefore performed a retrospective, multicenter, double-blinded validation study of eight BE progression prediction methylation biomarkers. Progression or nonprogression were determined at 2 years (tier 1) and 4 years (tier 2). Methylation was assayed in 145 nonprogressors and 50 progressors using real-time quantitative methylation-specific PCR. Progressors were significantly older than nonprogressors (70.6 versus 62.5 years; P < 0.001). We evaluated a linear combination of the eight markers, using coefficients from a multivariate logistic regression analysis. Areas under the ROC curve (AUC) were high in the 2-year, 4-year, and combined data models (0.843, 0.829, and 0.840; P < 0.001, <0.001, and <0.001, respectively). In addition, even after rigorous overfitting correction, the incremental AUCs contributed by panels based on the 8 markers plus age versus age alone were substantial (Delta-AUC = 0.152, 0.114, and 0.118, respectively) in all 3 models. A methylation biomarker-based panel to predict neoplastic progression in BE has potential clinical value in improving both the efficiency of surveillance endoscopy and the early detection of neoplasia.

The miR-106b-25 polycistron, activated by genomic amplification, functions as an oncogene by suppressing p21 and Bim.

BACKGROUND & AIMS: Barrett's esophagus (BE) is a highly premalignant disease that predisposes to the development of esophageal adenocarcinoma (EAC); however, the involvement of microRNAs (miRs) in BE-EAC carcinogenic progression is not known. METHODS: Esophageal cultured cells (HEEpiC, QhTRT, ChTRT, GihTRT, and OE-33) and esophageal tissues (22 normal epithelia, 24 BE, and 22 EAC) were studied. MiR microarrays and quantitative reverse-transcription polymerase chain reaction (RT-PCR) were employed to explore and verify differentially expressed miRs. Quantitative genomic PCR was performed to study copy number variation at the miR-106b-25 polycistron and MCM7 gene locus on chromosome 7q22.1. In vitro cell proliferation, cell cycle, and apoptosis assays and in vivo tumorigenesis experiments were performed to elucidate biologic effects of the miR-106b-25 polycistron. Western blotting and luciferase assays were performed to confirm direct messenger RNA (mRNA) targeting by the miR-106b-25 polycistron. RESULTS: The miR-106b-25 polycistron exerted potential proliferative, antiapoptotic, cell cycle-promoting effects in vitro and tumorigenic activity in vivo. MiRs-93 and -106b targeted and inhibited p21, whereas miR-25 targeted and inhibited Bim. This polycistron was upregulated progressively at successive stages of neoplasia, in association with genomic amplification and overexpression of MCM7. In addition, miRs-93 and -106b decreased p21 mRNA, whereas miR-25 did not alter Bim mRNA, suggesting the following discrete miR effector mechanisms: (1) for p21, mRNA degradation; (2) for Bim, translational inhibition. CONCLUSIONS: The miR-106b-25 polycistron is activated by genomic amplification and is potentially involved in esophageal neoplastic progression and proliferation via suppression of 2 target genes: p21 and Bim.

Rarity of Somatic Mutation and Frequency of Normal Sequence Variation Detected in Sporadic Colon Adenocarcinoma Using High-Throughput cDNA Sequencing.

We performed high-throughput cDNA sequencing in colorectal adenocarcinoma and matching normal colorectal epithelium. All six hundred three genes in the UCSC database that were expressed in colon cancers and contained open reading frames of 1000 nucleotides or less were selected for study (total basepairs/bp, 366,686). 304,350 of these 366,686 bp (83.0%) were amplified and sequenced successfully. Seventy-eight sequence variants present in germline (i.e. normal) as well as matching somatic (i.e. tumor) DNA were discovered, yielding a frequency of 1 variant per 3,902 bp. Fifty-one of these sequence variants were homozygous (26 synonymous, 25 non-synonymous), while 27 were heterozygous (11 synonymous, 16 non-synonymous). Cancer tissue contained only one sequence-altered allele of the gene ATP50, which was present heterozygously alongside the wild-type allele in matching normal epithelium. Despite this relatively large number of bp and genes sequenced, no somatic mutations unique to tumor were found. High-throughput cDNA sequencing is a practical approach for detecting novel sequence variations and alterations in human tumors, such as those of the colon.

Reprimo methylation is a potential biomarker of Barrett's-Associated esophageal neoplastic progression.

PURPOSE: Reprimo, a candidate tumor-suppressor gene, regulates p53-mediated cell cycle arrest at G2 phase, and tumor-suppressor gene methylation is involved in the pathogenesis and progression of esophageal cancer. Our aim was to determine whether and at what phase of neoplastic progression Reprimo methylation occurs in Barrett's adenocarcinogenesis, as well as its columnar or squamous cell-type specificity. We also sought to determine whether Reprimo expression could be restored in vitro by the demethylating agent 5-aza-deoxycytidine (5AzaC). EXPERIMENTAL DESIGN: Quantitative methylation-specific PCR for Reprimo was done using an ABI7700 (Taqman) apparatus on 175 endoscopic biopsy specimens. In addition, reverse transcription-PCR and quantitative methylation-specific PCR were done on esophageal carcinoma cells before and after treatment with 5AzaC. RESULTS: In Barrett's esophagus (BE; P=0.001), high-grade dysplasia (HGD; P=0.001), and esophageal adenocarcinoma (EAC; P=0.00003), the level and frequency of Reprimo methylation were significantly higher than in normal esophagus (NE). There was no statistically significant difference between BE and EAC, HGD and EAC, or NE and esophageal squamous cell carcinoma (ESCC). Reprimo methylation occurred in 0 of 19 NE samples, 6 (13%) of 45 ESCC, 9 (36%) of 25 BE, 7 (64%) of 11 HGD, and 47 (63%) of 75 EAC. Analysis of Reprimo methylation in EAC versus NE revealed an area under the receiver-operator characteristic curve of 0.812 (P<0.00001; 95% confidence interval, 0.73-0.90). In vitro 5AzaC treatment of OE33 EAC cells reduced Reprimo methylation and increased Reprimo expression. CONCLUSIONS: Reprimo methylation occurs significantly more frequently in BE, HGD, and EAC than in NE or ESCC, suggesting that this epigenetic alteration is a specialized columnar, cell-specific early event with potential as a biomarker for the early detection of esophageal neoplasia.