Masha Kocherginsky

Genetic Variants in the UDP-glucuronosyltransferase 1A1 Gene Predict the Risk of Severe Neutropenia of Irinotecan

PURPOSE Severe toxicity is commonly observed in cancer patients receiving irinotecan. UDP-glucuronosyltransferase 1A1 (UGT1A1) catalyzes the glucuronidation of the active metabolite SN-38. This study prospectively evaluated the association between the prevalence of severe toxicity and UGT1A1 genetic variation. PATIENTS AND METHODS Sixty-six cancer patients with advanced disease refractory to other treatments received irinotecan 350 mg/m(2) every 3 weeks. Toxicity and pharmacokinetic data were measured during cycle 1. UGT1A1 variants (-3279G>T, -3156G>A, promoter TA indel, 211G>A, 686C>A) were genotyped. RESULTS The prevalence of grade 4 neutropenia was 9.5%. Grade 4 neutropenia was much more common in patients with the TA indel 7/7 genotype (3 of 6 patients; 50%) compared with 6/7 (3 of 24 patients; 12.5%) and 6/6 (0 of 29 patients; 0%) (P =.001). The TA indel genotype was significantly associated with the absolute neutrophil count nadir (7/7 < 6/7 < 6/6, P =.02). The relative risk of grade 4 neutropenia was 9.3 (95% CI, 2.4 to 36.4) for the 7/7 patients versus the rest of the patients. Pretreatment total bilirubin levels (mean +/- standard deviation) were significantly higher in patients with grade 4 neutropenia (0.83 +/- 0.08 mg/dL) compared to those without grade 4 neutropenia (0.47 +/- 0.03 mg/dL; P <.001). The -3156G>A variant seemed to distinguish different phenotypes of total bilirubin within the TA indel genotypes. The -3156 genotype and the SN-38 area under the concentration versus time curve were significant predictors of ln(absolute neutrophil count nadir; r(2) = 0.51). CONCLUSION UGT1A1 genotype and total bilirubin levels are strongly associated with severe neutropenia, and could be used to identify cancer patients predisposed to the severe toxicity of irinotecan. The hypothesis that the -3156G>A variant is a better predictor of UGT1A1 status than the previously reported TA indel requires further testing.

Phase III Randomized Trial of Induction Chemotherapy in Patients With N2 or N3 Locally Advanced Head and Neck Cancer

PURPOSE Induction chemotherapy (IC) before radiotherapy lowers distant failure (DF) rates in locally advanced squamous cell carcinoma of the head and neck (SCCHN). The goal of this phase III trial was to determine whether IC before chemoradiotherapy (CRT) further improves survival compared with CRT alone in patients with N2 or N3 disease. PATIENTS AND METHODS Treatment-naive patients with nonmetastatic N2 or N3 SCCHN were randomly assigned to CRT alone (CRT arm; docetaxel, fluorouracil, and hydroxyurea plus radiotherapy 0.15 Gy twice per day every other week) versus two 21-day cycles of IC (docetaxel 75 mg/m(2) on day 1, cisplatin 75 mg/m(2) on day 1, and fluorouracil 750 mg/m(2) on days 1 to 5) followed by the same CRT regimen (IC + CRT arm). The primary end point was overall survival (OS). Secondary end points included DF-free survival, failure pattern, and recurrence-free survival (RFS). RESULTS A total of 285 patients were randomly assigned. The most common grade 3 to 4 toxicities during IC were febrile neutropenia (11%) and mucositis (9%); during CRT (both arms combined), they were mucositis (49%), dermatitis (21%), and leukopenia (18%). Serious adverse events were more common in the IC arm (47% v 28%; P = .002). With a minimum follow-up of 30 months, there were no statistically significant differences in OS (hazard ratio, 0.91; 95% CI, 0.59 to 1.41), RFS, or DF-free survival. CONCLUSION IC did not translate into improved OS compared with CRT alone. However, the study was underpowered because it did not meet the planned accrual target, and OS was higher than predicted in both arms. IC cannot be recommended routinely in patients with N2 or N3 locally advanced SCCHN.

Progression of Barrett's Metaplasia to Adenocarcinoma Is Associated with the Suppression of the Transcriptional Programs of Epidermal Differentiation

We did expressional profiling on 24 paired samples of normal esophageal epithelium, Barretts metaplasia, and esophageal adenocarcinomas. Matching tissue samples representing the three different histologic types were obtained from each patient undergoing esophagectomy for adenocarcinoma. Our analysis compared the molecular changes accompanying the transformation of normal squamous epithelium with Barretts esophagus and adenocarcinoma in individual patients rather than in a random cohort. We tested the hypothesis that expressional profiling may reveal gene sets that can be used as molecular markers of progression from normal esophageal epithelium to Barretts esophagus and adenocarcinoma. Expressional profiling was done using U133A GeneChip (Affymetrix), which represent approximately two thirds of the human genome. The final selection of 214 genes permitted the discrimination of differential gene expression of normal esophageal squamous epithelium, Barretts esophagus, and adenocarcinoma using two-dimensional hierarchical clustering of selected genes. These data indicate that transformation of Barretts esophagus to adenocarcinoma is associated with suppression of the genes involved in epidermal differentiation, including genes in 1q21 loci and corresponding to the epidermal differentiation complex. Correlation analysis of genes concordantly expressed in Barretts esophagus and adenocarcinoma revealed 21 genes that represent potential genetic markers of disease progression and pharmacologic targets for treatment intervention. PCR analysis of genes selected based on DNA array experiments revealed that estimation of the ratios of GATA6 to SPRR3 allows discrimination among normal esophageal epithelium, Barretts dysplasia, and adenocarcinoma.

Activation of the glucocorticoid receptor is associated with poor prognosis in estrogen receptor-negative breast cancer

Estrogen receptor-negative (ER(-)) breast cancers have limited treatment options and are associated with earlier relapses. Because glucocorticoid receptor (GR) signaling initiates antiapoptotic pathways in ER(-) breast cancer cells, we hypothesized that activation of these pathways might be associated with poor prognosis in ER(-) disease. Here we report findings from a genome-wide study of GR transcriptional targets in a premalignant ER(-) cell line model of early breast cancer (MCF10A-Myc) and in primary early-stage ER(-) human tumors. Chromatin immunoprecipitation with massively parallel sequencing (ChIP-seq) coupled to time-course expression profiling led us to identify epithelial-to-mesenchymal transition (EMT) pathways as an important aspect associated with GR activation. We validated these findings by carrying out a meta-analysis of primary breast tumor gene expression from 1,378 early-stage breast cancer patients with long-term clinical follow-up, confirming that high levels of GR expression significantly correlated with shorter relapse-free survival in ER(-) patients who were treated or untreated with adjuvant chemotherapy. Notably, in ER(+) breast cancer patients, high levels of GR expression in tumors were significantly associated with better outcome relative to low levels of GR expression. Gene expression analysis revealed that ER(-) tumors expressing high GR levels exhibited differential activation of EMT, cell adhesion, and inflammation pathways. Our findings suggest a direct transcriptional role for GR in determining the outcome of poor-prognosis ER(-) breast cancers.

Practical Confidence Intervals for Regression Quantiles

Routine applications of quantile regression analysis require reliable and practical algorithms for estimating standard errors, variance-covariance matrices, as well as confidence intervals. Because the asymptotic variance of a quantile estimator depends on error densities, some standard large-sample approximations have been found to be highly sensitive to minor deviations from the iid error assumption. In this article we propose a time-saving resampling method based on a simple but useful modification of the Markov chain marginal bootstrap (MCMB) to construct confidence intervals in quantile regression. This method is compared to several existing methods with favorable performance in speed, accuracy, and reliability. We also make practical recommendations based on the quantreg package contributed by Roger Koenker and a new package rqmcmb2 developed by the first two authors. These recommendations also apply to users of the new SAS procedure PROC QUANTREG, available from Version 9.2 of SAS.

miR‐143 and miR‐145 are downregulated in ulcerative colitis: Putative regulators of inflammation and protooncogenes

Background: miR‐143 and miR‐145 are believed to function as colon cancer tumor suppressors, as they inhibit colon cancer cell growth and are downregulated in sporadic colonic tumors. We speculated that miR‐143 and miR‐145 might also be downregulated and contribute to malignant transformation of colonic epithelium in longstanding ulcerative colitis (UC). Methods: Biopsies were obtained 20 cm proximal to the anus from individuals with quiescent UC and from normal controls. RNA and proteins were extracted and measured. miR‐143 and miR‐145 were quantified by real‐time polymerase chain reaction (PCR) and miR‐145 was also assessed by in situ hybridization. Putative targets of these miRNAs, K‐RAS, API5, MEK‐2 (miR‐143), and IRS‐1 (miR‐145) were determined by western blotting. To assess the effects of miR‐143 and miR‐145 on these predicted targets, HCT116 and HCA‐7 colorectal cancer cells were transfected with miR‐143 and miR‐145 and expression levels of these proteins were measured. Results: In UC, miR‐143 and miR‐145 were significantly downregulated 8.3‐fold (3.4–20.1) (P < 0.0001) and 4.3‐fold (2.3–7.8) (P < 0.0001), respectively, compared to normal colon. In contrast, IRS‐1, K‐RAS, API5, and MEK‐2 were upregulated in UC, consistent with their assignments as targets of these miRNAs. Furthermore, transfected miR‐143 and miR‐145 significantly downregulated these proteins in HCT116 or HCA‐7 cells. Conclusions: Compared to normal colonic mucosa, in chronic UC miR‐143 and miR‐145 were significantly downregulated and their predicted targets, IRS‐1, K‐RAS, API5, and MEK‐2 were upregulated. We postulate that loss of these tumor suppressor miRNAs predispose to chronic inflammation and neoplastic progression in IBD. (Inflamm Bowel Dis 2011;)

Dexamethasone decreases xenograft response to paclitaxel through inhibition of tumor cell apoptosis

Glucocorticoid receptor (GR) activation has recently been implicated in the initiation of anti-apoptotic signaling pathways in epithelial cell lines grown in culture. However, the evidence that GR-mediated inhibition of tumor cell apoptosis is the mechanism that diminishes chemotherapy effectiveness in vivo is limited. We therefore initiated a breast cancer xenograft study to examine whether or not pretreatment with GCs decreases tumor response to chemotherapy by inhibiting tumor cell apoptosis. Here we report a significant decrease in paclitaxel-induced apoptosis in xenografts from mice pretreated with dexamethasone (Dex). A significant difference in apoptosis in xenografts from Dex/paclitaxel versus paclitaxel treated animals was seen eight days following initiation of chemotherapy. Nine days later, mice treated with Dex/paclitaxel had significantly larger tumors compared with those that received paclitaxel alone (p=0.032). Dex pretreatment did not significantly affect tumor cell proliferation rates. Taken together, these results demonstrate that systemic Dex administration results in significantly reduced breast cancer xenograft apoptosis in the context of chemotherapy treatment. We also found that systemic Dex treatment results in upregulation of the anti-apoptotic gene MKP-1 and downregulation of pro-apoptotic Bid and TRAIL genes in tumor cells six hours following Dex treatment. These in vivo gene expression changes correlated with significant inhibition of chemotherapy-induced apoptosis. Interestingly, the decreased chemotherapeutic response of Dex-pretreated tumors persisted for several weeks following treatment. These data suggest that GR-mediated transcriptional regulation of pro- and anti-apoptotic genes contributes to the mechanism through which GCs decrease paclitaxel-induced apoptosis.

Geriatric assessment to predict survival in older allogeneic hematopoietic cell transplantation recipients

Allogeneic hematopoietic cell transplantation is increasingly utilized in older adults. This study prospectively evaluated the prognostic utility of geriatric assessment domains prior to allogeneic transplantation in recipients aged 50 years and over. Geriatric assessment was performed prior to transplant, and included validated measures across domains of function and disability, comorbidity, frailty, mental health, nutritional status, and systemic inflammation. A total of 203 patients completed geriatric assessment and underwent transplant. Median age was 58 years (range 50–73). After adjusting for established prognostic factors, limitations in instrumental activities of daily living (HR 2.38, 95%CI: 1.59–3.56; P<0.001), slow walk speed (HR 1.80, 95%CI: 1.14–2.83; P=0.01), high comorbidity by hematopoietic cell transplantation-specific comorbidity index (HR 1.56, 95%CI: 1.07–2.28; P=0.02), low mental health by short-form-36 mental component summary (HR 1.67, 95%CI: 1.13–2.48; P=0.01), and elevated serum C-reactive protein (HR 2.51, 95%CI: 1.54–4.09; P<0.001) were significantly associated with inferior overall survival. These associations were more pronounced in the cohort 60 years and over. Geriatric assessment measures confer independent prognostic utility in older allogeneic transplant recipients. Implementation of geriatric assessment prior to allogeneic transplantation may aid appropriate selection of older adults.

A Model of Gene-Environment Interaction Reveals Altered Mammary Gland Gene Expression and Increased Tumor Growth following Social Isolation

Clinical studies have revealed that social support improves the outcome of cancer patients, whereas epidemiologic studies suggest that social isolation increases the risk of death associated with several chronic diseases. However, the precise molecular consequences of an unfavorable social environment have not been defined. To do so, robust, reproducible preclinical models are needed to study the mechanisms whereby an adverse environment affects gene expression and cancer biology. Because random assignment of inbred laboratory mice to well-defined social environments allows accurate and repeated measurements of behavioral and endocrine parameters, transgenic mice provide a preclinical framework with which to begin to determine gene-environment mechanisms. In this study, we found that female C3(1)/SV40 T-antigen mice deprived of social interaction from weaning exhibited increased expression of genes encoding key metabolic pathway enzymes in the premalignant mammary gland. Chronic social isolation was associated with up-regulated lipid synthesis and glycolytic pathway gene expression—both pathways are known to contribute to increased breast cancer growth. Consistent with the expression of metabolic genes in premalignant mammary tissue, isolated mice subsequently developed a significantly larger mammary gland tumors burden compared with group-housed mice. Endocrine evaluation confirmed that isolated mice developed a heightened corticosterone stress response compared with group-housed mice. Together, these transdisciplinary studies show for the first time that an adverse social environment is associated with altered mammary gland gene expression and tumor growth. Moreover, the identification of specific alterations in metabolic pathways gene expression favoring tumor growth suggests potential molecular biomarkers and/or targets (e.g., fatty acid synthesis) for preventive intervention in breast cancer.

Suppression of Metastatic Colonization by the Context-Dependent Activation of the c-Jun NH2-Terminal Kinase Kinases JNKK1/MKK4 and MKK7

Advances in clinical, translational, and basic studies of metastasis have identified molecular changes associated with specific facets of the metastatic process. Studies of metastasis suppressor gene function are providing a critical mechanistic link between signaling cascades and biological outcomes. We have previously identified c-Jun NH2-terminal kinase (JNK) kinase 1/mitogen-activated protein kinase (MAPK) kinase 4 (JNKK1/MKK4) as a prostate cancer metastasis suppressor gene. The JNKK1/MKK4 protein is a dual-specificity kinase that has been shown to phosphorylate and activate the JNK and p38 MAPKs in response to a variety of extracellular stimuli. In this current study, we show that the kinase activity of JNKK1/MKK4 is required for suppression of overt metastases and is sufficient to prolong animal survival in the AT6.1 model of spontaneous metastasis. Ectopic expression of the JNK-specific kinase MKK7 suppresses the formation of overt metastases, whereas the p38-specific kinase MKK6 has no effect. In vivo studies show that both JNKK1/MKK4 and MKK7 suppress the formation of overt metastases by inhibiting the ability of disseminated cells to colonize the lung (secondary site). Finally, we show that JNKK1/MKK4 and MKK7 from disseminated tumor cells are active in the lung but not in the primary tumor, providing a biochemical explanation for why their expression specifically suppressed metastasis while exerting no effect on the primary tumor. Taken together, these studies contribute to a mechanistic understanding of the context-dependent function of metastasis regulatory proteins.