Amir A. Jazaeri

Gene expression profiles derived from fine needle aspiration correlate with response to systemic chemotherapy in breast cancer

BackgroundDrug resistance in breast cancer is a major obstacle to successful chemotherapy. In this study we used cDNA microarray technology to examine gene expression profiles obtained from fine needle aspiration (FNA) of primary breast tumors before and after systemic chemotherapy. Our goal was to determine the feasibility of obtaining representative expression array profiles from limited amounts of tissue and to identify those expression profiles that correlate with treatment response.MethodsRepeat presurgical FNA samples were taken from six patients who were to undergo primary surgical treatment. Additionally, a group of 10 patients who were to receive neoadjuvant chemotherapy underwent two FNAs before chemotherapy (adriamycin 60 mg/m2 and cyclophosphamide 600 mg/m2) followed by another FNA on day 21 after the first cycle. Total RNA was amplified with T7 Eberwines procedure and labeled cDNA was hybridized onto a 7600-feature glass cDNA microarray.ResultsWe identified candidate gene expression profiles that might distinguish tumors with complete response to chemotherapy from tumors that do not respond, and found that the number of genes that change after one cycle of chemotherapy was 10 times greater in the responding group than in the non-responding group.ConclusionThis study supports the suitability of FNA-derived cDNA microarray expression profiling of breast cancers as a comprehensive genomic approach for studying the mechanisms of drug resistance. Our findings also demonstrate the potential of monitoring post-chemotherapy changes in expression profiles as a measure of pharmacodynamic effect and suggests that these approaches might yield useful results when validated by larger studies.

Gene Expression Profiles Associated with Response to Chemotherapy in Epithelial Ovarian Cancers

Purpose: The goal of this study was to determine whether distinct gene expression profiles are associated with intrinsic and/or acquired chemoresistance in epithelial ovarian carcinoma. Experimental Design: Gene expression profiles were generated from 21 primary chemosensitive tumors and 24 primary chemoresistant tumors using cDNA-based microarrays. Gene expression profiles of both groups of primary tumors were then compared with those of 15 ovarian carcinomas obtained following platinum-based chemotherapy (“postchemotherapy” tumors). A theme discovery tool was used to identify functional categories of genes involved in drug resistance. Results: Comparison of primary chemosensitive and chemoresistant tumors revealed differential expression of 85 genes (P < 0.001). Comparison of gene expression profiles of primary chemosensitive tumors and postchemotherapy tumors revealed more robust differences with 760 genes differentiating the two groups (P < 0.001). In contrast, only 230 genes were differentially expressed between primary chemoresistant and postchemotherapy groups (P < 0.001). Common to both gene lists were 178 genes representing transcripts differentially expressed between postchemotherapy tumors and all primary tumors irrespective of intrinsic chemosensitivity. The gene expression profile of postchemotherapy tumors compared with that of primary tumors revealed statistically significant overrepresentation of genes encoding extracellular matrix–related proteins. Conclusions: These data show that gene expression profiling can discriminate primary chemoresistant from primary chemosensitive ovarian cancers. Gene expression profiles were also identified that correlate with states of intrinsic and acquired chemoresistance and that represent targets for future investigation and potential therapeutic interventions.

The role of miR-31 and its target gene SATB2 in cancer-associated fibroblasts

It is well established that there is a dynamic relationship between the expanding tumor and the host surrounding tissue. Cancer-associated fibroblasts (CAFs), the most common cellular population found in the tumor microenvironment, supporting tumor growth and dissemination. Here, we set out to determine the factors that may be involved in dramatic alteration of gene expression pattern in CAFs, focusing on microRNA and transcriptional regulators. We established matched pairs of human CAFs isolated from endometrial cancer and normal endometrial fibroblasts. MicroRNA and mRNA analyses identified differential expression of 11 microRNAs, with miR-31 being the most downregulated microRNA in CAFs (p=0.007). We examined several putative miR-31 target genes identified by microarray analysis and demonstrated that miR-31 directly targets the homeobox gene SATB2, which is responsible for chromatin remodeling and regulation of gene expression, and was significantly elevated in CAFs. The functional relevance of miR-31 and SATB2 were tested in in vitro models of endometrial cancer. Overexpression of miR-31 significantly impaired the ability of CAFs to stimulate tumor cell migration and invasion, without affecting tumor cell proliferation. Genetic manipulation of SATB2 levels in normal fibroblasts or CAFs showed that, reciprocally to miR-31, SATB2 increased tumor cell migration and invasion, while knock-down of endogenous SATB2 in CAFs reversed this phenotype. Introduction of SATB2 into normal fibroblasts stimulated expression of a number of genes involved in cell invasion, migration and scattering. These findings provide new insights into tumor-stroma interaction and document that miR

CRL4Cdt2 E3 Ubiquitin Ligase Monoubiquitinates PCNA to Promote Translesion DNA Synthesis

Monoubiquitination of proliferating cell nuclear antigen (PCNA) is a critical posttranslational modification essential for DNA repair by translesion DNA synthesis (TLS). The Rad18 E3 ubiquitin ligase cooperates with the E2 Rad6 to monoubiquitinate PCNA in response to DNA damage. How PCNA is monoubiquitinated in unperturbed cells and whether this plays a role in the repair of DNA associated with replication is not known. We show that the CRL4(Cdt2) E3 ubiquitin ligase complex promotes PCNA monoubiqutination in proliferating cells in the absence of external DNA damage independent of Rad18. PCNA monoubiquitination via CRL4(Cdt2) is constitutively antagonized by the action of the ubiquitin-specific protease 1 (USP1). In vitro, CRL4(Cdt2) monoubiquitinates PCNA at Lys164, the same residue that is monoubiquitinated by Rad18. Significantly, CRL4(Cdt2) is required for TLS in nondamaged cells via a mechanism that is dependent on PCNA monoubiquitination. We propose that CRL4(Cdt2) regulates PCNA-dependent TLS associated with stresses accompanying DNA replication.

Molecular determinants of tumor differentiation in papillary serous ovarian carcinoma

In epithelial ovarian cancer, tumor grade is an independent prognosticator whose molecular determinants remain unknown. We investigated patterns of gene expression in well‐ and poorly differentiated serous papillary ovarian and peritoneal carcinomas with cDNA microarrays. A 6500‐feature cDNA microarray was used for comparison of the molecular profiles of eight grade III and four grade I stage III serous papillary adenocarcinomas. With a modified F‐test in conjunction with random permutations, 99 genes whose expression was significantly different between grade I and grade III tumors were identified (P < 0.01). A disproportionate number of these differentially expressed genes were located on the chromosomal regions 20q13 and all exhibited higher expression in grade III tumors. Interphase fluorescent in situ hybridization demonstrated 20q13 amplification in two of the four grade III and none of the three grade I tumors available for evaluation. Several centrosome‐related genes also showed higher expression in grade III tumors. We propose a model in which tumor differentiation is inversely correlated with the overexpression of several oncogenes located on 20q13, a common amplicon in ovarian and numerous other cancers. Dysregulation of centrosome function is one potential mechanistic link between genetic/epigenetic changes and the poorly differentiated phenotype in ovarian cancer. Published 2003 Wiley‐Liss, Inc.

Silencing of miR-148a in cancer-associated fibroblasts results in WNT10B-mediated stimulation of tumor cell motility.

The tumor microenvironment has an important role in cancer progression. Here we show that miR-148a is downregulated in 15 out of 16 samples (94%) of cancer-associated fibroblasts (CAFs) compared with matched normal tissue fibroblasts (NFs) established from patients with endometrial cancer. Laser-capture microdissection of stromal cells from normal tissue and endometrial cancer confirmed this observation. Treatment of cells with 5-aza-deoxycytidine stimulated the expression of miR-148a in the majority of CAFs implicating DNA methylation in the regulation of miR-148a expression. Investigation of miR-148a function in fibroblasts demonstrated that conditioned media (CM) from CAFs overexpressing miR-148a significantly impaired the migration of five endometrial cancer cell lines without affecting their growth rates in co-culture experiments. Among predicted miR-148a target genes are two WNT family members, WNT1 and WNT10B. Activation of the WNT/β-catenin pathway in CAFs was confirmed by microarray analysis of gene expression and increased activity of the SuperTOPFlash luciferase reporter. We found elevated levels of WNT10B protein in CAFs and its level decreased when miR-148a was re-introduced by lentiviral infection. The 3′-UTR of WNT10B, cloned downstream of luciferase cDNA, suppressed luciferase activity when co-expressed with miR-148a indicating that WNT10B is a direct target of miR-148a. In contrast to the effect of miR-148a, WNT10B stimulated migration of endometrial cancer cell lines. Our findings have defined a molecular mechanism in the tumor microenvironment that is a novel target for cancer therapy.

Frailty: An outcome predictor for elderly gynecologic oncology patients☆

OBJECTIVES The objective of this pilot study was to determine if frailty predicts surgical complications among elderly women undergoing gynecologic oncology procedures. METHODS A cohort of gynecologic oncology patients age ≥ 65, undergoing surgery between March and December 2011 was identified. Frailty was evaluated using a validated assessment tool. The primary outcome measure was 30 day postoperative complication rate. RESULTS Forty women were approached for study entry and 37 (92%) enrolled. The mean age was 73 years (range 65-95). The majority of women had a malignancy and underwent a major abdominal surgical procedure. Twenty-one women (57%) were not frail, 10 (27%) were intermediately frail and 6 (16%) were frail. There was no difference in age or prevalence of medical comorbidities between groups. Frail women had a significantly higher BMI compared to intermediately frail and not frail women, (36.0, 31.5 and 26.1 kg/m(2), p=0.02). The rate of 30-day surgical complications increased with frailty score and was 24%, versus 67% for women who were not frail as compared to the frail (p=0.04). CONCLUSIONS Pre-operative frailty assessment is well accepted by gynecologic oncology patients and feasible in a clinic setting. Frail women had a higher BMI, indicating that low body weight is not a marker for frailty, and had a significantly higher rate of 30-day postoperative complications in this pilot study. Initial findings support the concept of measuring frailty as a possible predictor for postoperative morbidity that will allow for improved patient counseling and decision making.

Core Biopsies Can Be Used to Distinguish Differences in Expression Profiling by cDNA Microarrays

The primary focus of this work was to determine the feasibility of obtaining representative expression array profiles from clinical core biopsies. For this purpose we performed six 16-gauge needle core biopsies and an excision biopsy on each of two different human xenografts, one from an Ewings sarcoma cell line and the second from neuroblastoma cell line grown in Beige-Scid mice. Three of the six core biopsies were processed separately and the remaining three were pooled and processed together. As the initial RNA material isolated from the core biopsies was not sufficient for microarray analysis, an amplification procedure using a modified Eberwine protocol was performed, and the amplified products applied onto a 6000-feature human cDNA microarray. Comparisons of the array results from core biopsies (amplified RNA) and surgical specimens (non-amplified RNA) showed maintenance of the expression profile as assessed by hierarchical clustering. Gene expression profiles obtained from microarray analysis clearly differentiated the Ewings sarcoma from the neuroblastoma with both core and excisional biopsies as starting material. Pooling the core biopsies did not improve the concordance with excisional biopsies. In conclusion, our results suggest that core biopsies can be used as a suitable and reliable material for the determination of tumor genetic profiles.

Overcoming Platinum Resistance in Preclinical Models of Ovarian Cancer Using the Neddylation Inhibitor MLN4924

The nearly ubiquitous development of chemoresistant disease remains a major obstacle against improving outcomes for patients with ovarian cancer. In this investigation, we evaluated the preclinical activity of MLN4924, an investigational inhibitor of the NEDD8-activating enzyme, in ovarian cancer cells. Efficacy of MLN4924 both alone and in combination with platinum was assessed. Overall, single-agent MLN4924 exhibited moderate activity in ovarian cancer cell lines. However, the combination of MLN4924 with cisplatin or carboplatin produced synergistic effects in SKOV3 and ES2 cells, as well as in primary ovarian cancer cell lines established from high-grade serous, clear cell, and serous borderline ovarian tumors. The efficacy of cisplatin plus MLN4924 was also evident in several in vitro models of platinum-resistant ovarian cancer. Mechanistically, the combination of cisplatin and MLN4924 was not associated with DNA re-replication, altered platinum-DNA adduct formation, abrogation of FANCD2 monoubiquitination, or CHK1 phosphorylation. An siRNA screen was used to investigate the contribution of each member of the cullin RING ligase (CRL) family of E3 ubiquitin ligases, the best-characterized downstream mediators of MLN4924s biologic effects. Cisplatin-induced cytotoxicity was augmented by depletion of CUL3, and antagonized by siCUL1 in both ES2 and SKOV3 ovarian cancer cells. This investigation identifies inhibition of neddylation as a novel mechanism for overcoming platinum resistance in vitro, and provides a strong rationale for clinical investigations of platinum and MLN4924 combinations in ovarian cancer. Mol Cancer Ther; 12(10); 1958–67. ©2013 AACR.

Cyclooxygenase-2 in cervical neoplasia: A review

OBJECTIVE Previous data demonstrate an association between cyclooxygenase activity and development of cervical cancer. This review investigates the role of cyclooxygenase-2 (COX-2) in the development of cervical cancer and potential therapeutic options targeting this pathway. METHODS A literature search was conducted using MEDLINE 1997-2007 utilizing the terms inflammation, cervical cancer, cyclooxygenase, COX-2, indomethacin, cervical intraepithelial neoplasia, and squamous cell cancer. Articles were included based on the quality of the study and pertinence to the topic. Other sources were culled from the references of the articles identified. RESULTS Over 150 abstracts were reviewed for inclusion. Studies in vivo and in vitro confirm the role of COX-2 in the development of cervical cancer. In addition, COX-2 overexpression is associated with an increase in angiogenesis markers. Clinical correlation found that COX-2 overexpression in cervical cancer patients is a poor prognostic marker associated with increased risk for recurrent or metastatic disease. Despite early promise, two phase II trials in use of specific COX-2 inhibitors as radio-sensitizers in locally advanced cervical cancer demonstrated increased toxicity with no change in therapeutic effect. Results of studies using COX-2 inhibitors in pre-invasive cervical disease are encouraging. CONCLUSIONS Treatment of cervical intraepithelial neoplasia with cyclooxygenase inhibitors may provide a medical alternative to surgical therapy.