Carine Tran-Perennou

A New Model of Patient Tumor-Derived Breast Cancer Xenografts for Preclinical Assays

Purpose: To establish a panel of human breast cancer (HBC) xenografts in immunodeficient mice suitable for pharmacologic preclinical assays. Experimental Design: 200 samples of HBCs were grafted into Swiss nude mice. Twenty-five transplantable xenografts were established (12.5%). Their characterization included histology, p53 status, genetic analysis by array comparative genomic hybridization, gene expression by Western blotting, and quantitative reverse transcription-PCR. Biological profiles of nine xenografts were compared with those of the corresponding patients tumor. Chemosensitivities of 17 xenografts to a combination of Adriamycin and cyclophosphamide (AC), docetaxel, trastuzumab, and Degarelix were evaluated. Results: Almost all patient tumors established as xenografts displayed an aggressive phenotype, i.e., high-grade, triple-negative status. The histology of the xenografts recapitulated the features of the original tumors. Mutation of p53 and inactivation of Rb and PTEN proteins were found in 83%, 30%, and 42% of HBC xenografts, respectively. Two HBCx had an ERBB2 (HER2) amplification. Large variations were observed in the expression of HER family receptors and in genomic profiles. Genomic alterations were close to those of original samples in paired tumors. Three xenografts formed lung metastases. A total of 15 of the 17 HBCx (88%) responded to AC, and 8 (47%) responded to docetaxel. One ERBB2-amplified xenograft responded to trastuzumab, whereas the other did not. The drug response of HBC xenografts was concordant with that of the patients tumor in five of seven analyzable cases. Conclusions: This panel of breast cancer xenografts includes 15 triple-negative, one ER positive and 2 ERBB2 positive. This panel represents a useful preclinical tool for testing new agents and protocols and for further exploration of the biological basis of drug responses.

Role of chemotherapy resistance genes in outcome of neuroblastoma.

Neuroblastoma is a heterogeneous pediatric disease. Most patients with localized disease usually have a favorable prognosis, but patients with advanced disease have a poor prognosis despite combination chemotherapy. Treatment failure may be attributable to resistance to cytotoxic drugs.

Quantitation of estradiol receptors alpha and beta and progesterone receptors in human breast tumors by real-time reverse transcription-polymerase chain reaction correlation with protein assays

Hormone receptor content is the most useful parameter for predicting hormone response therapy in breast cancer. The high frequency of primary and secondary resistance to treatment makes it necessary to find out other parameters in order to improve the prediction of response to treatment. The newly described estrogen receptor beta (ERbeta) is a potential candidate. Using real-time quantitative RT-PCR, we evaluated estrogen receptor alpha (ERalpha), ERbeta, and progesterone receptors (PR) in comparison with ERalpha and PR protein content measured with the enzyme immunoassay (EIA), in a retrospective series of 98 breast tumors. We obtained a highly significant correlation between mRNA and EIA assays for ERalpha and PR (r=0.79 and r=0.71, respectively; P<0.001). We confirmed the low level of ERbeta mRNA transcripts in comparison to ERalpha in breast tumors. We did not find any statistically significant correlation between the absolute ERbeta mRNA level and ERalpha or PR mRNA level, and ERalpha or PR-EIA. We found a significant correlation between ERalpha mRNA and PR mRNA expressions. We did not find any correlation between ERbeta mRNA and clinical features of the patients (age, menopausal status, tumor size, and nodal status), nor with the histological type of the tumor. In conclusion, the accuracy of the present quantitative RT-PCR assay makes it suitable for a routine clinical use. In addition, the present results suggest that, ERbeta mRNA expression is independent of the classical parameters.

In vivo efficacy of STI571 in xenografted human small cell lung cancer alone or combined with chemotherapy.

STI571, or imatinib, selectively inhibits BCR/ABL, PDGFR and c‐kit kinase activity. It has been reported that a large proportion of small cell lung cancer (SCLC) cell lines and tumors express c‐kit and that STI571 inhibits tumor cell growth. We therefore investigated the therapeutic efficacy of STI571, alone or combined with chemotherapy, in human SCLC cells or tumors xenografted into nude mice. The level of c‐kit mRNA expression was variable in SCLC tumors (positive for 2 of 4 xenografts), and c‐kit protein was not detected by immunohistochemistry. On the 4 xenografted tumors, PDGFRα and PDGFRβ were not detected by immunohistochemistry. STI571 induced inhibition of proliferation of the SCLC6 cell line without inducing apoptosis; in contrast, in combination with etoposide or topotecan, the growth inhibition of SCLC6 cells induced by STI571 was increased, with apoptotic DNA fragmentation. Four human SCLC xenografts (SCLC6, SCLC61, SCLC74 and SCLC108) were transplanted into mice. After intraperitoneal injection of STI571, we observed 80%, 40% and 78% growth inhibition of SCLC6, SCLC61 and SCLC108 tumors, respectively, without any significant inhibition of SCLC74 tumor growth. In mice bearing responsive SCLC tumors, we observed an increase of growth inhibition induced by chemotherapy (etoposide + ifosfamide or topotecan) by concomitant and continuous administration of STI571, associated with an increase of toxic deaths. In SCLC6‐bearing mice receiving sequential treatments, we observed a reduction of toxic deaths but a decrease of synergistic antitumor efficacy. In conclusion, the efficacy of STI571 alone in SCLC xenografted tumors was variable and did not depend on c‐kit expression. Moreover, a significant increase of chemotherapy‐induced growth inhibition was obtained by concomitant administration of STI571 that should be carefully investigated in SCLC patients.

Expression of progesterone and estradiol receptors in normal adrenal cortex, adrenocortical tumors, and primary pigmented nodular adrenocortical disease

Adrenal tumors occur more frequently in women and are the leading cause of Cushings syndrome during pregnancy. We aimed to evaluate the potential role of sex steroids in the susceptibility of women to adrenocortical tumors. We evaluated the presence of the progesterone receptor (PR), estradiol receptors (ERs), and aromatase in 5 patients with primary pigmented nodular adrenal disease (PPNAD), 15 adrenocortical adenomas (ACAs) and adjacent normal tissues, 12 adrenocortical carcinomas (ACCs), and 3 normal adrenal glands (NA). The expression of PR and ERalpha was evaluated by enzyme immunoassays, real-time RT-PCR, immunohistochemistry, and cytosol-based ligand-binding assays. ERbeta and aromatase levels were evaluated by real-time RT-PCR. ERalpha concentrations were low in NA, in adrenal tissues adjacent to ACA (51+/-33), in ACC (53+/-78), and lower in ACA (11+/-11 fmol/mg DNA). Conversely, PR concentrations were high in NA and adrenal tissues adjacent to ACA, at 307+/-216 fmol/mg DNA, and were even higher in tumors - 726+/-706 fmol/mg DNA in ACA and 1154+/-1586 fmol/mg DNA in ACC - and in isolated PPNAD nodules. Binding study results in four tumors were compatible with binding to a steroid receptor. In patients with PPNAD, a strong positive immunohistochemical signal was associated with the sole isolated nodular regions. ERbeta transcript levels were very high in all samples except those for two ACCs, whereas aromatase levels were low. PR and ERbeta are clearly present in normal adrenal glands and adrenal tumors. Further studies may shed light on the possible pathogenic role of these receptors in adrenal proliferation.

Gefitinib and chemotherapy combination studies in five novel human non small cell lung cancer xenografts. Evidence linking EGFR signaling to gefitinib antitumor response.

The epidermal growth factor receptor (EGFR) signaling pathway is often activated in NSCLC, and thus represents a promising therapeutic target. We studied the antitumor activity of gefitinib (Iressa™), an orally active EGFR‐tyrosine kinase inhibitor, alone and in combination with standard chemotherapy in 5 recently established human NSCLC xenografts with wild‐type EGFR. Mice were treated with 2 protocols of chemotherapy based on cisplatin (CDDP) combined with either gemcitabine (GEM) or vinorelbine (VNR). Gefitinib alone significantly inhibited tumor growth (TGI) in 4 of the 5 tumor xenografts (mean TGI of 58%, range: 25–70%). CDDP+VNR alone failed to achieve any significant responses, while CDDP+GEM achieved significant responses in 2 xenografts (TGI of 93 and 47%). Addition of gefitinib to CDDP+GEM potentialized chemotherapy in the 3 CDDP+GEM‐resistant xenografts, but did not potentialize the CDDP+VNR combination. The effect of gefitinib treatment on the activity of extra cellular‐regulated kinase (Erk), Akt, JNK and p38 kinases was assessed in IC9LC11 and IC1LC131, two NSCLC xenografts selected for their sensitivity and resistance to gefitinib, respectively. In IC9LC11, gefitinib strongly inhibited Erk, Akt and Jnk phosphorylation, but P38 remained active. Inversely, in IC1LC131, Erk and Akt pathways remained active, while Jnk and P38 pathways were inhibited by gefitinib. The data indicate that the antitumor activity of gefitinib in NSCLC, alone or in combination with chemotherapy, is tumor‐dependent and is influenced by downstream signaling events independent of EGFR status.

Tumor aromatase expression as a prognostic factor for local control in young breast cancer patients after breast-conserving treatment

IntroductionWe sought to determine whether the levels of expression of 17 candidate genes were associated with locoregional control after breast-conserving treatments of early-stage breast cancers in young, premenopausal women.MethodsGene expression was measured by using RT-PCR in the breast tumors of a series of 53 young (younger than 40 years), premenopausal patients. All treatments consisted of primary breast-conserving surgery followed by whole-breast radiotherapy (± regional lymph nodes) with or without systemic treatments (chemotherapy ± hormone therapy). The median follow-up was 10 years.ResultsThe 10-year locoregional control rate was 70% (95% CI, 57% to 87%). In univariate analysis, no clinical/pathologic prognostic factors were found to be significantly associated with decreased locoregional control. Expression of three genes was found to be significantly associated with an increased locoregional recurrence rate: low estrogen-receptor β, low aromatase, and high GATA3. Two others were associated with only a trend (P < 0.10): low HER1 and SKP2. In multivariate analysis, only the absence of aromatase was significantly associated with an increased locoregional recurrence rate (P = 0.003; relative risk = 0.49; 95% CI 0.29 to 0.82).ConclusionsRecent data give credit to the fact that breast cancer in young women is a distinct biologic entity driven by special oncogenic pathways. Our results highlight the role of estrogen-signaling pathways (mainly CYP19/aromatase, GATA3, and ER-β) in the risk of locoregional recurrence of breast cancer in young women. Confirmation in larger prospective studies is needed.