Poly (ADP) ribose polymerase (PARP) plays a key role in DNA repair and is highly expressed in small cell lung cancer (SCLC). We investigated the therapeutic impact of PARP inhibition in SCLC. In vitro cytotoxicity of veliparib, cisplatin, carboplatin, and etoposide singly and combined was determined by MTS in 9 SCLC cell lines (H69, H128, H146, H526, H187, H209, DMS53, DMS153, and DMS114). Subcutaneous xenografts in athymic nu/nu mice of H146 and H128 cells with relatively high and low platinum sensitivity, respectively, were employed for in vivo testing. Mechanisms of differential sensitivity of SCLC cell lines to PARP inhibition were investigated by comparing protein and gene expression profiles of the platinum sensitive and the less sensitive cell lines. Veliparib showed limited single-agent cytotoxicity but selectively potentiated (≥50% reduction in IC50) cisplatin, carboplatin, and etoposide in vitro in five of nine SCLC cell lines. Veliparib with cisplatin or etoposide or with both cisplatin and etoposide showed greater delay in tumor growth than chemotherapy alone in H146 but not H128 xenografts. The potentiating effect of veliparib was associated with in vitro cell line sensitivity to cisplatin (CC = 0.672; P = 0.048) and DNA-PKcs protein modulation. Gene expression profiling identified differential expression of a 5-gene panel (GLS, UBEC2, HACL1, MSI2, and LOC100129585) in cell lines with relatively greater sensitivity to platinum and veliparib combination. Veliparib potentiates standard cytotoxic agents against SCLC in a cell-specific manner. This potentiation correlates with platinum sensitivity, DNA-PKcs expression and a 5-gene expression profile.
Carboplatin; cisplatin; etoposide; PARP; SCLC; veliparib (ABT-888)
The current study was conducted to develop a multifactorial statistical model to predict the specific head and neck (H&N) tumor site origin in cases of squamous cell carcinoma confined to the cervical lymph nodes (“unknown primaries”).
The Surveillance, Epidemiology, and End Results (SEER) database was analyzed for patients with an H&N tumor site who were diagnosed between 2004 and 2011. The SEER patients were identified according to their H&N primary tumor site and clinically positive cervical lymph node levels at the time of presentation. The SEER patient data set was randomly divided into 2 data sets for the purposes of internal split-sample validation. The effects of cervical lymph node levels, age, race, and sex on H&N primary tumor site were examined using univariate and multivariate analyses. Multivariate logistic regression models and an associated set of nomograms were developed based on relevant factors to provide probabilities of tumor site origin.
Analysis of the SEER database identified 20,011 patients with H&N disease with both site-level and lymph node-level data. Sex, race, age, and lymph node levels were associated with primary H&N tumor site (nasopharynx, hypopharynx, oropharynx, and larynx) in the multivariate models. Internal validation techniques affirmed the accuracy of these models on separate data.
The incorporation of epidemiologic and lymph node data into a predictive model has the potential to provide valuable guidance to clinicians in the treatment of patients with squamous cell carcinoma confined to the cervical lymph nodes.
unknown primary; Surveillance; Epidemiology; End Results (SEER); cervical lymph nodes; predictive model; radiation
We present a pipeline to perform integrative analysis of mate-pair (MP) and paired-end (PE) genomic DNA sequencing data. Our pipeline detects structural variations (SVs) by taking aligned sequencing read pairs as input and classifying these reads into properly paired and discordantly paired categories based on their orientation and inferred insert sizes. Recurrent SV was identified from the discordant read pairs. Our pipeline takes into account genomic annotation and genome repetitive element information to increase detection specificity. Application of our pipeline to whole-genome MP and PE sequencing data from three multiple myeloma cell lines (KMS11, MM.1S, and RPMI8226) recovered known SVs, such as heterozygous TRAF3 deletion, as well as a novel experimentally validated SPI1 – ZNF287 inter-chromosomal rearrangement in the RPMI8226 cell line.
structural variations; multiple myeloma; whole-genome sequencing; variant detection
Aberrant promoter DNA methylation can serve as a predictive biomarker for improved clinical responses to certain chemotherapeutics. One of the major advantages of methylation biomarkers is the ease of detection and clinical application. In order to identify methylation biomarkers predictive of a response to a taxane-platinum based chemotherapy regimen in advanced NSCLC we performed an unbiased methylation analysis of 1,536 CpG dinucleotides in cancer-associated gene loci and correlated results with clinical outcomes.
We studied a cohort of 49 patients (median age 62 years) with advanced NSCLC treated at the Atlanta VAMC between 1999 and 2010. Methylation analysis was done on the Illumina GoldenGate Cancer panel 1 methylation microarray platform. Methylation data were correlated with clinical response and adjusted for false discovery rates.
Cav1 methylation emerged as a powerful predictor for achieving disease stabilization following platinum taxane based chemotherapy (p = 1.21E-05, FDR significance = 0.018176). In Cox regression analysis after multivariate adjustment for age, performance status, gender, histology and the use of bevacizumab, CAV1 methylation was significantly associated with improved overall survival (HR 0.18 (95%CI: 0.03–0.94)). Silencing of CAV1 expression in lung cancer cell lines(A549, EKVX)by shRNA led to alterations in taxane retention.
CAV1 methylation is a predictor of disease stabilization and improved overall survival following chemotherapy with a taxane-platinum combination regimen in advanced NSCLC. CAV1 methylation may predict improved outcomes for other chemotherapeutic agents which are subject to cellular clearance mediated by caveolae.
We performed a retrospective cohort analysis of 701 (533 White and 144 Black) patients with DLBCL treated at two referral centers in southern United States between 1981-2010. Median age of diagnosis for Blacks was 50 years vs. 57 years for Whites (p<0.001). A greater percentage of Blacks presented with elevated lactate dehydrogenase levels, B-symptoms, and performance status≥2. More Whites (8%) than Blacks (3%) had positive family history of lymphoma (p=0.048). There were no racial differences in the use of R-CHOP (52% Black vs. 47% White, p=0.73). While black race predicted worse survival among patients treated with CHOP (Hazard ratio [HR] 1.8, p<0.001), treatment with R-CHOP was associated with improved survival irrespective of race (HR 0.61, p=0.01). Future studies should examine biological differences that may underlie the observed racial differences in presentation and outcome.
Diffuse large B-cell lymphoma; Race; Disparities; Outcomes; CHOP regimen; R-CHOP regimen
Escalation with overdose control (EWOC) is a Bayesian adaptive design for selecting dose levels in cancer Phase I clinical trials while controlling the posterior probability of exceeding the maximum tolerated dose (MTD). EWOC has been used by clinicians to design many cancer Phase I clinical trials, see e.g [1-4]. However, this design treats the toxicity response as a binary indicator of dose limiting toxicity (DLT) and does not account for the number and specific grades of toxicities experienced by patients during the trial. Chen et al. (2010) proposed a novel toxicity score system to fully utilize all toxicity information using a normalized equivalent toxicity score (NETS). In this paper, we propose to incorporate NETS into EWOC using a quasi-Bernoulli likelihood approach to design cancer Phase I clinical trials. We call the design escalation with overdose control using normalized equivalent toxicity score (EWOC-NETS). Simulation results show that this design has good operating characteristics and improves the accuracy of MTD, trial efficiency, therapeutic effect, and overdose control relative to EWOC which is used as a representative of designs treating toxicity response as a binary indicator of DLT. We illustrate the performance of this design using real trial data in identifying the Phase II dose.
Escalation with Overdose Control; Maximum Tolerated Dose; Multiple Toxicities; Quasi-continuous; Normalized Equivalent Toxicity Score; Toxicity Score System
The preoperative diagnosis of thyroid nodules primarily depends upon fine needle aspiration (FNA) cytology. However, up to 25% of FNA samples have associated “suspicious or indeterminate”, but not diagnostic cytologic reports, resulting in difficulty deciding appropriate clinical management for these patients. We hypothesize that the use of molecular markers as an adjunct to FNA cytology can improve the distinction of benign from malignant nodules that have associated suspicious or indeterminate cytology.
Using microarray analysis, we previously identified and reported on 75 genes useful in the distinction of benign versus malignant thyroid nodules. In the present study, we have further validated the expression of 14 of these markers in a large number of thyroid samples by immunohistochemistry (IHC) analysis of 154 thyroid tumors and quantitative real-time RT-PCR (QRT-PCR) analysis of 95 FNA samples. Of the 154 tumors analyzed by IHC, 44 samples (29%) had associated suspicious or indeterminate FNA cytology.
Receiver operating characteristic using three-gene model, (HMGA2, MRC2, and SFN) analysis for the detection of malignant nodules resulted in areas under the curve (AUCs) of≥0.95 (80% sensitivity; 100% specificity) and≥0.84 (71% sensitivity; 84% specificity) for the IHC data in tumors, and QRT-PCR data in FNA samples, respectively.
Our results suggest that a three-gene model for the cytological diagnosis of indeterminate thyroid nodules is both feasible and promising. Implementation of this as an adjunct to thyroid cytology may significantly impact the clinical management of patients with suspicious or indeterminate thyroid FNA nodules.
The role of estrogen receptor alpha (ER) in breast cancer development and as a primary clinical marker for breast cancer prognosis is well documented. In this study, we identified the oncogenic protein TWIST1 (Twist), which is over-expressed in high-grade breast cancers, as a potential negative regulator of ER expression. Functional characterization of ER regulation by Twist was carried out using Twist low (MCF-7, T-47D) and Twist high (Hs 578T, MDA-MB-231, MCF-7/Twist) expressing cell lines. All Twist high cell lines exhibited low ER transcript and protein levels. By chromatin immunoprecipitation and promoter assays, we demonstrated that Twist could directly bind to E-boxes in the ER promoter and significantly down-regulate ER promoter activity in vitro. Functionally, Twist over-expression caused estrogen independent proliferation of breast cells and promoted hormone resistance to the selective estrogen receptor modulator (SERM) tamoxifen and selective estrogen receptor down-regulator (SERD) fulvestrant. Importantly, this effect was reversible on down-regulating Twist. Additionally, orthotopic tumors generated in mice using MCF-7/Twist cells were resistant to tamoxifen. These tumors had high vascular volume and permeability surface area as determined by magnetic resonance imaging (MRI). Mechanistically, Twist recruited DNA methyltransferase 3B (DNMT3B) to the ER promoter leading to a significantly higher degree of ER promoter methylation compared to parental cells. Furthermore, we demonstrated by co-immunoprecipitation that Twist interacted with histone deacetylase 1 (HDAC1) at the ER promoter, causing histone deacetylation and chromatin condensation, further reducing ER transcript levels. Functional re-expression of ER was achieved using demethylating agent 5-azacytidine and histone deacetylase inhibitor valproic acid. Finally, an inverse relationship was observed between Twist and ER expression in human breast tumors. In summary, the regulation of ER by Twist could be an underlying mechanism for loss of ER activity observed in breast tumors and may contribute to the generation of hormone resistant ER negative breast cancer.
Breast cancer; estrogen receptor; hormone resistance; TWIST1; Twist; transcriptional regulation; chromatin immunoprecipitation; co-immunoprecipitation; histone deacetylation; histone deacetylase 1 (HDAC1); methylation; DNA methyltransferase 3B (DNMT3B)
Isotonic Design using Normalized Equivalent Toxicity Score (ID-NETS) is a novel Phase I design that integrates the novel toxicity scoring system originally proposed by Chen et al.  and the original Isotonic Design proposed by Leung et al. . ID-NETS has substantially improved the accuracy of maximum tolerated dose (MTD) estimation and trial efficiency in the Phase I clinical trial setting by fully utilizing all toxicities experienced by each patient and treating toxicity response as a quasi-continuous variable instead of a binary indicator of dose limiting toxicity (DLT). To facilitate the incorporation of the ID-NETS method into the design and conduct of Phase I clinical trials, we have designed and developed a user-friendly software, ID-NETS©TM, which has two functions: 1) Calculating the recommended dose for the subsequent patient cohort using available completed data; and 2) Performing simulations to obtain the operating characteristics of a trial designed with ID-NETS. Currently, ID-NETS©TMv1.0 is available for free download at http://winshipbbisr.emory.edu/IDNETS.html.
Isotonic design; normalized equivalent toxicity score; maximum tolerated dose; dose limiting toxicity; cancer phase I clinical trial; software.
Cancer stem cells (CSCs) are functionally defined by their ability to self-renew and recapitulate tumors in the ectopic setting. They have been identified in a growing number of human malignancies and their association with poor clinical outcomes has suggested that they are a major factor in dictating clinical outcomes. Moreover, recent studies have demonstrated that CSCs may display other functional attributes, such as drug resistance and invasion and migration, that implicates a broad role in clinical oncology spanning initial tumor formation, relapse following treatment, and disease progression. Although our knowledge regarding the basic biology of CSCs continues to improve, a major issue remains proof that they are clinically relevant, and translation of the CSC hypothesis from the lab to the clinic is of paramount importance. We will review current evidence supporting the role of CSCs in clinical oncology and discuss potential barriers and strategies in designing trials examining CSC-targeting agents.
Cancer stem cells; Metastasis; Drug resistance; Antineoplastic agents
High-dose cyclophosphamide has long been used an anticancer agent, a conditioning regimen for hematopoietic stem cell transplantation and as potent immunosuppressive agent in autoimmune diseases including aplastic anemia. High-dose cyclophosphamide is highly toxic to lymphocytes but spares hematopoietic stem cells because of their abundant levels of aldehyde dehydrogenase, the major mechanism of cyclophosphamide inactivation. High dose cyclophosphamide therapy induces durable remissions in most patients with acquired aplastic anemia. Moreover, high-dose cyclophosphamide without hematopoietic stem cell rescue has shown activity in a variety of other severe autoimmune diseases. Here we review the history of cyclophosphamide as is applies to aplastic anemia (AA) and other autoimmune diseases. Included here are the historical data from early patients treated for AA as well as an observational retrospective study in a single tertiary care hospital. This latter component was designed to assess the safety and efficacy of high-dose cyclophosphamide therapy without stem cell rescue in patients with refractory autoimmune diseases. We analyzed fully the 140 patients with severe, progressive autoimmune diseases treated. All patients discussed here received cyclophosphamide, 50 mg/kg per day for 4 consecutive days. Response, relapse and overall survival were measured. Response was defined as a decrease in disease activity in conjunction with a decrease or elimination of immune modulating drugs. Relapse was defined as worsening disease activity and/or a requirement of an increase in dose of, or administration of new, immunosuppressive medications. Hematologic recovery occurred in all patients. The overall response rate of the was 95%, and 44% of those patients remain progression-free with a median follow up time of 36 (range 1–120) months for the 140 patients analyzed together. The overall actuarial and event free survival across all diseases at 60 months is 90.7% and 20.6%, respectively. High- dose cyclophosphamide without stem cell rescue is well-tolerated and induces a high rate of remissions in severe autoimmune diseases.
Stem Cell transplantation; Cyclophosphamide; Autoimmune diseases; Autoimmunity; Hematologic recovery
Though tyrosine kinase inhibitors have redefined the care of chronic myeloid leukemia (CML), these agents have not proved curative, likely due to resistance of the leukemia stem cells (LSC). While a number of potential therapeutic targets have emerged in CML, their expression in the LSC remains largely unknown. We therefore isolated subsets of CD34+ stem/progenitor cells from normal donors and from patients with chronic phase or blast crisis CML. These cell subsets were then characterized based on ability to engraft immunodeficient mice and expression of candidate therapeutic targets. The CD34+CD38− CML cell population with high aldehyde dehydrogenase (ALDH) activity was the most enriched for immunodeficient mouse engrafting capacity. The putative targets: PROTEINASE 3, SURVIVIN, and hTERT were expressed only at relatively low levels by the CD34+CD38−ALDHhigh CML cells, similar to the normal CD34+CD38−ALDHhigh cells and less than in the total CML CD34+ cells. In fact, the highest expression of these antigens was in normal, unfractionated CD34+ cells. In contrast, PRAME and WT1 were more highly expressed by all CML CD34+ subsets than their normal counterparts. Thus, ALDH activity appears to enrich for CML stem cells, which display an expression profile that is distinct from normal stem/progenitor cells and even the CML progenitors. Indeed, expression of a putative target by the total CD34+ population in CML does not guarantee expression by the LSC. These expression patterns suggest that PROTEINASE 3, SURVIVIN, and hTERT are not optimal therapeutic targets in CML stem cells; whereas PRAME and WT1 seem promising.
chronic myeloid leukemia; CML; leukemia stem cell; WT1; PRAME
Although the high mobility group A1 (HMGA1) gene is widely overexpressed in diverse cancers and portends a poor prognosis in some tumors, the molecular mechanisms that mediate its role in transformation have remained elusive. HMGA1 functions as a potent oncogene in cultured cells and induces aggressive lymphoid tumors in transgenic mice. Because HMGA1 chromatin remodeling proteins regulate transcription, HMGA1 is thought to drive malignant transformation by modulating expression of specific genes. Genome-wide studies to define HMGA1 transcriptional networks during tumorigenesis, however, are lacking. To define the HMGA1 transcriptome, we analyzed gene expression profiles in lymphoid cells from HMGA1a transgenic mice at different stages in tumorigenesis.
RNA from lymphoid samples at 2 months (before tumors develop) and 12 months (after tumors are well-established) was screened for differential expression of > 20,000 unique genes by microarray analysis (Affymetrix) using a parametric and nonparametric approach. Differential expression was confirmed by quantitative RT-PCR in a subset of genes. Differentially expressed genes were analyzed for cellular pathways and functions using Ingenuity Pathway Analysis. Early in tumorigenesis, HMGA1 induced inflammatory pathways with NFkappaB identified as a major node. In established tumors, HMGA1 induced pathways involved in cell cycle progression, cell-mediated immune response, and cancer. At both stages in tumorigenesis, HMGA1 induced pathways involved in cellular development, hematopoiesis, and hematologic development. Gene set enrichment analysis showed that stem cell and immature T cell genes are enriched in the established tumors. To determine if these results are relevant to human tumors, we knocked-down HMGA1 in human T-cell leukemia cells and identified a subset of genes dysregulated in both the transgenic and human lymphoid tumors.
We found that HMGA1 induces inflammatory pathways early in lymphoid tumorigenesis and pathways involved in stem cells, cell cycle progression, and cancer in established tumors. HMGA1 also dyregulates genes and pathways involved in stem cells, cellular development and hematopoiesis at both early and late stages of tumorigenesis. These results provide insight into HMGA1 function during tumor development and point to cellular pathways that could serve as therapeutic targets in lymphoid and other human cancers with aberrant HMGA1 expression.
Although previous studies have established a prominent role for HMGA1 (formerly HMG-I/Y) in aggressive human cancers, the role of HMGA2 (formerly HMGI-C) in malignant transformation has not been clearly defined. The HMGA gene family includes HMGA1, which encodes the HMGA1a and HMGA1b protein isoforms, and HMGA2, which encodes HMGA2. These chromatin binding proteins function in transcriptional regulation and recent studies also suggest a role in cellular senescence. HMGA1 proteins appear to participate in cell cycle regulation and malignant transformation, while HMGA2 has been implicated primarily in the pathogenesis of benign, mesenchymal tumors. Here, we show that overexpression of HMGA2 leads to a transformed phenotype in cultured lung cells derived from normal tissue. Conversely, inhibiting HMGA2 expression blocks the transformed phenotype in metastatic human non-small cell lung cancer cells. Moreover, we show that HMGA2 mRNA and protein are overexpressed in primary human lung cancers compared to normal tissue or indolent tumors. In addition, there is a statistically significant correlation between HMGA2 protein staining by immunohistochemical analysis and tumor grade (p < 0.001). Our results indicate that HMGA2 is an oncogene important in the pathogenesis of human lung cancer. Although additional studies with animal models are needed, these findings suggest that targeting HMGA2 could be beneficial therapeutically in lung and other cancers characterized by increased HMGA2 expression.
HMGA2; lung cancer; oncogene; antisense; transformation
Complete loss or deletion of the long arm of chromosome 5 is frequent in myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). The putative gene(s) deleted and responsible for the pathogenesis of these poor prognosis hematological disorders remain controversial. This study is a comprehensive analysis of previously implicated and novel genes for epigenetic inactivation in AML and MDS. In 146 AML cases, methylation of CTNNA1 was frequent, and more common in AML patients with 5q deletion (31%) than those without 5q deletion (14%), while no methylation of other 5q genes was observed. In 31 MDS cases, CTNNA1 methylation was only found in high risk MDS (≥RAEB2), but not in low risk MDS (
del(5q); monosomy 5; CTNNA1; methylation; myelodysplastic syndrome; acute myelogenous leukemia; methylation; Progressive silencing; AML transformation
Although some reports have found increasing HLA disparity between donor and recipient to be associated with fewer relapses after allogeneic blood or marrow transplantation (BMT), this potential benefit has been offset by more graft-versus-host disease (GVHD) and nonrelapse mortality. However, the type of GVHD prophylaxis could influence the balance between GVHD toxicity and relapse. We analyzed the impact of greater HLA disparity on outcomes of a specific platform for nonmyeloablative, HLA-haploidentical transplantation. A retrospective analysis was performed on 185 patients with hematologic malignancies enrolled on three similar trials of nonmyeloablative, related donor, haploidentical BMT incorporating high-dose posttransplantation cyclophosphamide for GVHD prophylaxis. No significant association was found between the number of HLA mismatches (HLA-A, -B, -Cw, and -DRB1 combined) and risk of acute grade II–IV GVHD (hazard ratio .89, P = .68 for 3–4 versus fewer antigen mismatches). More mismatching also had no detrimental effect on event-free survival (on multivariate analysis, hazard ratio .60, P = .03 for 3–4 versus fewer antigen mismatches; hazard ratio .55, P = .03 for 3–4 versus fewer allele mismatches). Thus, greater HLA disparity does not appear to worsen overall outcomes after nonmyeloablative haploidentical BMT with high-dose posttransplantation cyclophosphamide.
Nonmyeloablative conditioning; allogeneic blood or marrow transplantation; graft-versus-host disease; human leukocyte antigens; cyclophosphamide
Although lung cancer is the leading cause of cancer death worldwide, the precise molecular mechanisms that give rise to lung cancer are incompletely understood. Here, we demonstrate that HMGA1 is an important oncogene that drives transformation in undifferentiated, large cell carcinoma. First, we show that the HMGA1 gene is overexpressed in lung cancer cell lines and primary human lung tumors. Forced overexpression of HMGA1 induces a transformed phenotype with anchorage-independent cell growth in cultured lung cells derived from normal tissue. Conversely, inhibiting HMGA1 expression blocks anchorage-independent cell growth in the H1299 metastatic, undifferentiated, large cell human lung carcinoma cells. We also demonstrate that the matrix metalloproteinase-2 (MMP-2) gene is a downstream target up-regulated by HMGA1 in large cell carcinoma cells. In chromatin immunoprecipitation experiments, HMGA1 binds directly to the MMP-2 promoter in vivo in large cell lung cancer cells, but not in squamous cell carcinoma cells. In large cell carcinoma cell lines, there is a significant, positive correlation between HMGA1 and MMP-2 mRNA. Moreover, interfering with MMP-2 expression blocks anchorage-independent cell growth in H1299 large cell carcinoma cells, indicating that the HMGA1-MMP-2 pathway is required for this transformation phenotype in these cells. Blocking MMP-2 expression also inhibits migration and invasion in the H1299 large cell carcinoma cells. Our findings suggest an important role for MMP-2 in transformation mediated by HMGA1 in large cell, undifferentiated lung carcinoma and support the development of strategies to target this pathway in selected tumors.
MMP-2; HMGA1; lung cancer; oncogene
Inflammation has been strongly implicated in prostate carcinogenesis, but the precise molecular mechanisms linking inflammation and carcinogenic DNA damage are not known. Induction of the polyamine catabolic enzyme, spermine oxidase (SMO) has been linked to increased reactive oxygen species (ROS) and DNA damage in human gastric and lung epithelial cells and suggest direct mechanistic links between inflammation, SMO activity, ROS production, and epithelial carcinogenesis that are likely relevant in prostate cancer.
Tissue microarrays consisting of matched normal and diseased specimens from patients diagnosed with prostate cancer, prostatic intraepithelial neoplasia (PIN), or proliferative inflammatory atrophy (PIA), as well as unaffected individuals, were stained for SMO expression and analyzed using image analysis techniques and TMAJ software tools.
Average SMO staining was significantly higher in prostate cancer and PIN tissues compared to patient-matched benign tissues. Benign tissues from prostate cancer, PIN, and PIA patients also exhibited significantly higher mean SMO expression versus tissues from prostate disease-free patients.
Tissues from patients diagnosed with prostate cancer and PIN exhibit, on average, locally increased SMO expression in regions of prostatic disease and higher overall SMO expression in prostatic epithelial cells compared to healthy individuals. Further studies are warranted to directly examine the role of SMO-produced ROS in prostate carcinogenesis.
prostate cancer; prostatic intraepithelial neoplasia; spermine oxidase; tissue microarrays; inflammation
Specific populations of highly tumorigenic cells are thought to exist in many human tumors, including pancreatic adenocarcinoma. However, the clinical significance of these tumor-initiating (ie, cancer stem) cells remains unclear. Aldehyde dehydrogenase (ALDH) activity can identify tumor-initiating cells and normal stem cells from several human tissues. We examined the prognostic significance and functional features of ALDH expression in pancreatic adenocarcinoma.
ALDH expression was analyzed by immunohistochemistry in 269 primary surgical specimens of pancreatic adenocarcinoma and examined for association with clinical outcomes and in paired primary tumors and metastatic lesions from eight pancreatic cancer patients who had participated in a rapid autopsy program. The clonogenic growth potential of ALDH-positive pancreatic adenocarcinoma cells was assessed in vitro by a colony formation assay and by tumor growth in immunodeficient mice (10–14 mice per group). Mesenchymal features of ALDH-positive pancreatic tumor cells were examined by using quantitative reverse transcription–polymerase chain reaction and an in vitro cell invasion assay. Gene expression levels and the invasive potential of ADLH-positive pancreatic cancer cells relative to the bulk cell population were examined by reverse transcription–polymerase chain reaction and an in vitro invasion assays, respectively. All statistical tests were two-sided.
ALDH-positive tumor cells were detected in 90 of the 269 primary surgical specimens, and their presence was associated with worse survival (median survival for patients with ALDH-positive vs ALDH-negative tumors: 14 vs 18 months, hazard ratio of death = 1.28, 95% confidence interval = 1.02 to 1.68, P = .05). Six (75%) of the eight patients with matched primary and metastatic tumor samples had ALDH-negative primary tumors, and in four (67%) of these six patients, the matched metastatic lesions (located in liver and lung) contained ALDH-positive cells. ALDH-positive cells were approximately five- to 11-fold more clonogenic in vitro and in vivo compared with unsorted or ALHD-negative cells, expressed genes consistent with a mesenchymal state, and had in vitro migratory and invasive potentials that were threefold greater than those of unsorted cells.
ALDH expression marks pancreatic cancer cells that have stem cell and mesenchymal features. The enhanced clonogenic growth and migratory properties of ALDH-positive pancreatic cancer cells suggest that they play a key role in the development of metastatic disease that negatively affects the overall survival of patients with pancreatic adenocarcinoma.
Pharmacologic differentiating agents have had relatively limited clinical success outside of the use of ATRA in acute promyelocytic leukemia and DNA methyltransferase inhibitors in myelodysplastic syndromes. The differentiating effects of such agents can be enhanced in combination with lineage-specific growth factors. We developed a dose finding trial to assess toxicity, differentiating activity, and clinical impact of the combination of bryostatin-1 and GM-CSF.
Patients with poor risk myeloid malignancies were eligible to enroll in a dose finding study of continuous infusion bryostatin-1 combined with a fixed dose of daily GM-CSF. Toxicities were graded per NCI CTC version 2.0 and pharmacokinetic and correlative study samples were obtained to assess the combination’s clinical and biologic differentiating effects.
Thirty-two patients were treated with the combination therapy and the dose determined to be most suitable for study in a larger trial was continuous infusion broystatin-1 at 16 µg/m2 for 14 days and subcutaneous GM-CSF at 125 µg/m2 daily for 14 days every 28 days. Arthralgias and myalgias limited further dose escalation. Clinically, the combination impacted differentiation with improvement of absolute neutrophil counts (p = 0.0001) in the majority of patients. Interestingly, there were two objective clinical responses, including a CR after a single cycle. Both the bryostatin-1 plasma concentrations and the correlative studies supported biologic activity of the combination at the doses where clinical responses were observed.
Combining growth factors with pharmacologic differentiating agents may increase their clinical effectiveness and further studies should focus on such combinations.
Leukemia; Differentiation therapy; Myelodysplastic syndrome; Growth factors; Bryostatin; Drug resistance
CML can be responsive to T cell mediated immunity. K562/GM-CSF is a GM-CSF producing vaccine derived from a CML cell line that expresses several CML associated antigens. A pilot study was developed to determine if K562/GM-CSF immunotherapy could improve clinical responses to imatinib mesylate (IM) in patients with chronic myeloid leukemia.
Patients with chronic phase CML who achieved at least a major cytogeneic response but remained with persistent, measurable disease despite one or more years on IM were eligible. Each was given a series of four vaccines administered in three week intervals, with or without topical imiquimod, while remaining on a stable dose of IM. CML disease burden was measured serially before and after vaccination.
Nineteen patients were vaccinated, with a median duration of previous IM therapy of 37 (13–53) months. Mean PCR measurements of BCR-ABL for the group declined significantly following the vaccines (p=0.03). Thirteen patients had a progressive decline in disease burden, 8 of whom had increasing disease burden prior to vaccination. Twelve patients achieved their lowest tumor burden measurements to date following vaccine, including seven subjects who became PCR-undetectable.
K562/GM-CSF vaccine appears to improve molecular responses in patients on IM, including achieving complete molecular remissions, despite long durations of previous IM therapy.
chronic myeloid leukemia; CML; immunotherapy; K562/GM-CSF vaccine
To determine if a history of injection drug use influences genotypic PI resistance to antiretroviral agents..
We assessed the presence of resistance mutations in PI-naive injection drug users (IDUs) and non-IDUs participating in the Women’s Interagency HIV Study. Eighteen HIV-infected participants who reported injection drug use prior to study enrollment and 32 HIV-infected non-IDUs contributed a total of 34 and 65 person-visits, respectively to analyses.
Based on data from multiple clones obtained from different time points from each individual we determined that primary PI resistance mutations were more frequent among person-visits contributed by IDUs (24%) than non-IDUs (8%, p=0.05). While neither reached statistical significance, diversity was higher within the protease region among study visits carrying PI resistant clones at both the nucleotide level (2.66 vs. 2.35; p=0.08) and at the amino acid level (1.60 vs. 1.32; p=0.23). Most of the primary resistance mutations could not be detected using the standard population sequencing employed in the clinical setting. Five of six individuals in whom clones encoding PI resistance mutations were identified failed PI-containing HAART within 12 months of therapy initiation.
Our findings indicate that more aggressive sampling for resistance mutations among viral clones prior to HAART initiation might permit selection of more effective treatment, particularly in IDUs.
Injection drug use; antiretroviral therapy; genotypic resistance; HIV; clonal sequencing; population sequencing
Although HMGA1 (high-mobility group A1; formerly HMG-I/Y) is an oncogene that is widely overexpressed in aggressive cancers, the molecular mechanisms underlying transformation by HMGA1 are only beginning to emerge. HMGA1 encodes the HMGA1a and HMGA1b protein isoforms, which function in regulating gene expression. To determine how HMGA1 leads to neoplastic transformation, we looked for genes regulated by HMGA1 using gene expression profile analysis. Here, we show that the STAT3 gene, which encodes the signaling molecule signal transducer and activator of transcription 3 (STAT3), is a critical downstream target of HMGA1a. STAT3 mRNA and protein are up-regulated in fibroblasts overexpressing HMGA1a and activated STAT3 recapitulates the transforming activity of HMGA1a in fibroblasts. HMGA1a also binds directly to a conserved region of the STAT3 promoter in vivo in human leukemia cells by chromatin immunoprecipitation and activates transcription of the STAT3 promoter in transfection experiments. To determine if this pathway contributes to HMGA1-mediated transformation, we investigated STAT3 expression in our HMGA1a transgenic mice, all of which developed aggressive lymphoid malignancy. STAT3 expression was increased in the leukemia cells from our transgenics but not in control cells. Blocking STAT3 function induced apoptosis in the transgenic leukemia cells but not in controls. In primary human leukemia samples, there was a positive correlation between HMGA1a and STAT3 mRNA. Moreover, blocking STAT3 function in human leukemia or lymphoma cells led to decreased cellular motility and foci formation. Our results show that the HMGA1a–STAT3 axis is a potential Achilles heel that could be exploited therapeutically in hematopoietic and other malignancies overexpressing HMGA1a.
Id1, which belongs to the Id family of helix-loop-helix transcription factors has been most associated with tumor progression and metastatsis; however, its significance in lung cancers has not been extensively explored. Here we seek to evaluate the expression of Id1 in a pilot study of nonsmall-cell lung cancers (NSCLCs) and determine its diagnostic and functional significance in these tumors. Paired normal and malignant lung tissues as well as a panel of NSCLC primary tumors and cell lines were evaluated for Id1 expression using Western blotting and quantitative RT-PCR. Functional assays were performed to evaluate the role of Id1 in tumor cell growth, migration and progression. We find Id1 expression is upregulated in squamous cell carcinoma when compared to adenocarcinoma of the lung and that expression of Id1 versus the normal control is variable in NSCLCs. We also note that Id1 expression in NSCLC cells is largely growth factor dependant and constitutive expression of Id1 in NSCLC cells significantly increases tumor cell migration without affecting cell proliferation. We conclude that Id1, as a mediator of tumor cell migration, may be an indicator of aggressive potential in nonsmall-cell lung cancers.
Results 1-25 (31)
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