Micro- and nanoscale engineering of cell signaling

It is increasingly recognized that cell signaling, as a chemical process, must be considered at the local, micrometer scale. Micro- and nanofabrication techniques provide access to these dimensions, with the potential to capture and manipulate the spatial complexity of intracellular signaling in experimental models. This review focuses on recent advances in adapting surface engineering for use with biomolecular systems that interface with cell signaling, particularly with respect to surfaces that interact with multiple receptor systems on individual cells. The utility of this conceptual and experimental approach is demonstrated in the context of epithelial cells and T lymphocytes, two systems whose ability to perform their physiological function is dramatically impacted by the convergence and balance of multiple signaling pathways.

Management and outcome of ovarian malignancy complicating pregnancy: an analysis of 41 cases and review of the literature

OBJECTIVE

The aims of this study are to summarize our experience of managing ovarian malignancy complicating pregnancy, to discuss the maternal and fetal outcomes, and to review the literature concerned.

METHODS

Forty-one patients with ovarian malignancies complicating pregnancy at Peking Union Medical College Hospital between 1990 and 2012 were retrospectively reviewed.

RESULTS

Of the 41 patients, malignancies included epithelial ovarian cancers (13/41, 31.7 %), epithelial borderline ovarian tumors (12/41, 29.3 %), ovarian malignant germ cell tumors (10/41, 24.4 %), sexcord stromal tumors (3/41, 7.3 %), metastatic ovarian tumors (2/41, 4.9 %), and primary ovarian choriocarcinoma (1/41, 2.4 %). The median overall survival was 30 months (range 3-165), with an overall mortality rate of 24.4 %. The pregnancy outcomes included termination in the first trimester (8/41, 19.5 %), full-term vaginal delivery (7/41, 17.0 %), full-term cesarean section (17/41, 41.5 %), and therapeutic cesarean section for premature birth (9/41, 22.0 %). One preterm newborn died, and the remaining 32 survived in healthy status. All patients underwent surgery, and those who deliberately delayed radical surgery had gloomy prognosis. Two patients received chemotherapy during pregnancy, and 24 patients started chemotherapy after pregnancy termination.

CONCLUSIONS

Management priority should be given to the malignancy of ovarian tumors at any stage of pregnancy. Surgical intervention is the main treatment modality, and delaying of radical surgery is not recommended for patients with suspicion of high malignancy. Early diagnosis and appropriate treatment could offer satisfactory prognosis.

Assessment of immunochemotherapy and stem cell transplantation on EBV-associated hemophagocytic lymphohistiocytosis in children: a systematic review and meta analysis

BACKGROUND AND OBJECTIVES

Although immunochemotherapy had been reported to be effective initial treatment for patients with Epstein Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH), and stem cell transplantation (SCT) was employed for patients with refractory disease, the long-term outcome of these patients underwent such treatment remained uncertain. The main purpose of this study was to make a primary system review on the outcome of EBV-HLH patients treated with immunochemotherapy and/or SCT.

MATERIAL AND METHODS

A system review and meta analysis was conducted on studies which collected from published PubMed and China Knowledge Resource Integrated Database (CNKI). The analysis was based on clinical characteristics and follow-up. Search strategy and selection criteria were identified by relevant articles, the period was defined from January 1990 to October 2010. Search terms included all relevant terms. English and Chinese language papers were reviewed.

RESULTS

A total of 11 articles include 342 EBV-HLH patients that were identified with our search terms fulfilled the eligibility criteria. Overall 104/342 patients (30.4%) died at the end of respective study. In 288 patients who did not receive SCT, 93/288 patients (32.3%) patients died. While in 54 patients who underwent SCT, 11/54 patients (20.4%) died at the end of respective study. Four articles had the contents both of immunochemotherapy and SCT. When using a meta analysis compared the mortality between immunochemotherapy and SCT groups, there was no statistical significance could be found, the Odds Ratio is 1.10 (0.43-2.84), (p = 0.84). When compared the mortality between SCT group and total EBV-HLH patients, there was still no statistical significance could be found, the Odds Ratio is 0.99 (0.39-2.53), (p = 0.98).

CONCLUSION

Etoposide-containing immunochemotherapy and SCT both decreased the mortality in EBV-HLH patients in the past decade. There was not enough evidence to suggest that SCT is better than immunochemotherapy in children with EBV-HLH. And such result may justify further research.

P1-06-15: A Genomic Predictor Developed from Breast Cancer Cell Lines Predicts Both Disease-Free Survival and Overall Survival in Breast Cancer Patients Treated with Doxorubicin and Cyclophosphamide: A Collaborative Project of the NSABP and Precision Therapeutics

Background: A cell line-derived multigene predictor of tumor response to doxorubicin + cyclophosphamide (MGP-AC) has been shown to predict the pathological complete response (pCR) in breast cancer patients from the National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-27. However, a cell line-derived MPG for doxorubicin + cyclophosphamide + docetaxel (MGP-ACT) was not predictive in patients from B-27. The purpose of this study was to further assess the performance of these predictors on disease-free survival (DFS) and overall survival (OS) in the same patient populations.

Methods: NSABP B-27 was a 3-arm trial of 2411 early-stage breast cancer patients randomized to receive 4 cycles of preoperative doxorubicin+cyclophosphamide (AC) or 4 cycles of AC followed by 4 cycles of docetaxel either pre-op (AC+T) or post-op (AC→T). MGPs for AC and ACT were developed based on the in vitro assay and microarray genomic profiles of 40 breast cancer cell lines. A higher MGP score indicates lower chemoresponse sensitivity.

Results: 322 patients with available microarray data were included for this analysis (103 treated with AC, 102 with AC+T, and 117 with AC→T). For patients treated with AC, a higher MGP-AC score was significantly associated with increased risk of disease progression (standardized hazard ratio [HR] [SD set to 1]=1.48, 95% confidence interval [CI]=1.02−2.15, p=0.043) or death (standardized HR=1.66, 95% CI=1.06−2.62, p=0.028) after adjusting for clinical covariates (ER status, clinical tumor size, lymph node status, and age). The addition of MGP-AC to the clinical model improves the accuracy in predicting five-year DFS: the area under the ROC curve improved from 63% to 72%. For patients treated with AC+T or AC→T, MGP-ACT was not predictive of either DFS (standardized HR=1.03, 95% CI=0.78−1.37, p=0.818) or OS (standardized HR=1.05, 95% CI=0.73−1.51, p=0.8).

Conclusions: A cell line-derived MGP for AC that was predictive of pCR was also predictive of DFS and OS in breast cancer patients treated with neoadjuvant AC. The MGP for ACT, which was not predictive for pCR, was not predictive of either DFS or OS in patients who received docetaxel after AC.

The B-27 study was funded by NCI PHS grants U10-CA-37377, U10-CA-69974, U10-CA-12027, U10-CA-69651, and U24-CA-114732, and received additional support from sanofi-aventis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-15.

Evaluation of the performance of breast cancer cell line–derived multigene predictors of chemotherapy response in multiple clinical trials

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Background: While various multi-gene predictors (MGPs) of chemotherapy response have been developed based on cancer patient primary tissues or cancer cell-lines, the accuracy and consistency of these predictors remain a concern in clinical validation studies. In this study we developed four unique MGPs for chemotherapy response from breast cancer cell lines and performed a systematic evaluation of the performance of these MGPs using data from five distinct clinical trials.

Methods: Forty-six immortalized breast cancer cell-lines were exposed to various concentrations of drug combinations [paclitaxel, 5-fluorouracil, doxorubicin, cyclophosphamide (TFAC); 5-fluorouracil, doxorubicin, cyclophosphamide (FAC); 5-fluorouracil, epirubicin, cyclophosphamide (FEC) and epirubicin, cyclophosphamide (EC)] using an in vitro chemosensitivity assay. Utilizing publicly available breast cancer cell-line microarray data, genes highly associated with in vitro chemosensitivity were selected as candidate MGPs. Five independent and publicly available clinical trials were used for validation. In three of these clinical trials patients were treated by TFAC, while EC, FAC or FEC were used in the other two trials. All five studies involved neoadjuvant chemotherapy treatment, and pathologic complete response (pCR) was used as the endpoint. The association of MGPs with pCR was assessed using receiver-operator curve (ROC) analysis and area under the ROC (AUC) was used to evaluate the performance of prediction.

Results: In five independent clinical trials, the MGPs predicted patient pCR to EC, FAC/FEC and three TFAC treatments with an AUC of, 0.671, 0.632, 0.735, 0.738 and 0.647 respectively.

Conclusions: In the five independent clinical trials in which patients were treated by various chemotherapy agents, the performance of MGPs is promising. These results demonstrate the feasibility of using breast cancer cell-line derived MGPs to predict breast cancer patients’ chemotherapy responses.

Comparison of the GMFM-66 and the PEDI Functional Skills Mobility domain in a group of Chinese children with cerebral palsy

BACKGROUND

Previous research has suggested there is a high level of comparability between the Gross Motor Function Measure-66 (GMFM-66) and the Pediatric Evaluation of Disability Inventory (PEDI) Functional Skills Mobility domain. However, there are only a few studies that have examined the correlations between these instruments. The purpose of this study was to determine the correlation between the GMFM-66 and the PEDI Functional Skills Mobility domain scaled scores in a group of Chinese children with spastic cerebral palsy, at the ages of 12-70 months, in order to explore the feasibility of using them interchangeably.

METHODS

Secondary data analysis was conducted of data collected during a prospective international collaborative study that used the GMFM-66 and the PEDI to examine the impact of treatment. This study examined the Pearson correlations between the GMFM-66 and the PEDI Functional Skills Mobility domain at six time points over the course of 28 consecutive weeks for 115 Chinese children who participated at baseline.

RESULTS

Pearson correlations between the GMFM-66 and the PEDI Functional Skills Mobility domain ranged from 0.83 to 0.90 for the six time points of data collection, with statistically significant P-values <0.0001 for each correlation.

CONCLUSIONS

These results support previous research that the GMFM-66 and the PEDI Functional Skills Mobility domain are complementary assessments that may be used interchangeably when it is not possible to administer both.

Study on Creep Behavior of PP/CaCO3 Molded by Vibration Injection Molding at Different Vibration Frequency and Vibration Pressure

Vibration injection molding technology has achieved some good properties, such as high impact strength and high tensile strength. Although many researchers have proved that the short-time mechanical properties of the polymer could be improved by vibration-injection molding technology, the long-time mechanical properties, such as the creep behavior, have not been paid enough attention. In this paper, the creep behavior of the calcium carbonate filled polypropylene (PP/CaCO3) prepared at various vibration conditions has been observed. The influences of the vibration pressure and the frequency on the mechanical properties and creep behavior were investigated via creep test and tensile test. Firstly, the tensile fracture strain reached the maximum (11%) at 0.72 Hz. Moreover, with the increasing vibration pressure amplitude, the tensile fracture strain would decrease. The changing tendency of tensile strength is basically contrary with the change of the tensile fracture strain. Secondly, when the vibration frequency reaches the 0.72 Hz, the tensile creep is larger than that of other frequencies samples at 50 MPa; meanwhile, the tensile creep of these PP/CaCO3 parts, which has been prepared at 0.48 Hz, decreases with the increasing vibration pressure amplitude. Finally, the dynamic mechanics analysis (DMA) and the wide-angle X-ray diffraction (WAXD) were adopted to analyze the reason of the creep behavior change. The different macromolecular chains mobility caused the different creep behavior.

Adjuvant chemotherapy for gastric cancer: Less drug, same efficacy

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Background: Adjuvant chemotherapy is proved to improve survival in gastric cancer by meta-analyses. However, no evidence showed the best regimen. We conducted a retrospective analysis to compare triplets with doublets in the adjuvant setting.

Methods: We collected data from January 2004 to December 2008 from patients performed radical surgery and adjuvant chemotherapy. Doublets were defined as 5-FU 750 mg/m2 (d1- 5) or capecitabine 1,000 mg/m2 (d1-14) plus cisplatin 60 mg/m2 (d1) or oxaliplatin 130 mg/m2 (d1), while triplets had epirubicin 50 mg/m2 (d1) added. Chemotherapy was initiated within 6 weeks after surgery, repeated every three weeks and planned for 6 cycles. Patients were followed up in the outpatient clinic until death or April 30, 2010. Cox proportional-hazard model and chi-square test were used to test statistical difference.

Results: A total of 316 patients (210 in doublets, 106 in triplets) had a median follow-up time of 47 months. 77 patients died at the end of follow-up (3-year survival of 67.4%).Two groups were well balanced except age (median age of 57 in doublets, 51 in triplets, p < 0.001). All the patients tolerated well, with few grade 3/4 side effects (21.9% in doublets, 30.2% in triplets, p = 0.107). Two groups had similar disease-free survival (median DFS, 16 months vs. 23 months, p = 0.656) and overall survival (3-year survival rate, 59.6% vs. 64.8%, p = 0.293). Subgroup analysis showed the same benefit on survival between the two groups.

Conclusions: Our study suggested doublets and triplets had the same efficacy as the adjuvant chemotherapy. Furthermore, doublets seem more cost-effective.

[Table: see text]

No significant financial relationships to disclose.

Abstract P2-09-39: Multi-Gene Predictors Developed from Breast Cancer Cell Lines To Predict Response to Chemotherapy: A Validation Study on US Oncology Study 02-103

PURPOSE: Multi-gene predictors (MGPs) of response to multidrug chemotherapy regimens were developed using an in vitro chemoresponse assay in which cell lines were exposed to chemotherapy. The goal of this study was to assess the predictive value of these MGPs using clinical breast cancer patient gene expression data from a clinical trial. METHOD: US Oncology 02-103 was a phase II trial in which women with stage II/III breast cancer were treated with neoadjuvant chemotherapy consisting of four cycles of fluorouracil/epirubicin/cyclophosphamide (FEC) followed by four cycles of docetaxel/capecitabine (TX). Most HER-2 positive patients also received trastuzumab. MGPs of FEC, TX and TFEC (docetaxel/fluorouracil/epirubicin/cyclophosphamide) sensitivity were developed using in vitro assay results from breast cancer cell lines exposed to these drug combinations and publicly-available gene expression data for the same cell lines. MGPs were not developed for trastuzumab treatment. Area under the receiver-operator curve (AUC) was used to evaluate the performance of the three MGPs’ to predict patient pathologic complete response (pCR). Patients who did or did not receive trastuzumab were evaluated separately. Validation was performed blindly and the predictors were applied without knowledge of patient clinical outcome. RESULTS: Eighty-six patients had genomic data available and were included in this analysis. The predictive performance of the FEC, TX and TFEC MGPs were AUCs of 0.72, 0.69, and 0.73, respectively, in the patients who received FEC-TX chemotherapy without trastuzumab (n=61). Within this group, higher AUCs were observed in ER-negative patients compared to ER-positive patients (0.69, 0.72, 0.74 vs. 0.64, 0.54, 0.62, respectively). The prediction accuracies were low (AUCs = 0.43, 0.56 and 0.43) for patients who received trastuzumab together with chemotherapy (n=25) as expected, indicating that the MGPs may have the potential to be regimen-specific.

CONCLUSION: Cell line-derived MGPs of multidrug chemotherapy regimens showed promising performance in this blinded validation study, particularly among patients with ER-negative breast cancers. Further clinical data are needed to confirm this finding.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-39.

Abstract P3-08-02: Pharmacogenomic Predictors of Patient Response to Chemotherapy Derived from Breast Cancer Cell Lines Combining Knowledge-Based and Data-Driven Methods

Background: Responses of breast cancer patients to chemotherapy treatments vary considerably, and population treatment response rates remain low. To improve patient outcomes, genomic profiles have been used to identify patients who would benefit from specific treatments. Several studies have used cancer cell lines to develop pharmacogenomic predictors by identifying genes associated with drug response. However, pharmacogenomic predictors derived by this data-driven approach may not readily elucidate the underlying mechanisms associated with drug responses, because the identified predictors by computational methods may not directly associate with drug responses considering the complex genetic regulatory network. To overcome this issue, we proposed a strategy to integrate data-driven methods with biological knowledge-based approaches to identify genomic predictors. We then applied this approach to breast cancer cell lines to identify genomic predictors of paclitaxel-5-fluorouracil-doxorubicin-cyclophosphamide (TFAC), the identified predictors are then evaluated by their ability to predict the clinical outcome of the breast cancer patients who are treated by TFAC. Material: Thirty immortalized breast cancer cell lines were exposed to various concentrations of TFAC using a chemosensitivity assay. Area under the dose-response curves was calculated to measure chemoresponses. Gene expression profiles of the 30 cell lines, the expression profiles as well as the pathologic complete response (pCR) information of 133 breast cancer patients treated by TFAC were publicly available. Methods: We performed pathway enrichment analysis in breast cancer cell lines to assess the association between drug response and curated gene sets predefined by molecular signature database. Pathways with p-value less than 0.01 were considered enriched. The genes from the enriched pathways whose expression values were highly correlated with drug sensitivity were selected as the pharmacogenomic predictors. To validate these predictors, the performances of their prediction for patients’ pCR were evaluated using principle component regression method.

Results: Using pathway enrichment analysis, 17 pathways were identified to be related to TFAC drug response. These pathways are related to different biological functions, including breast cancer ER status and BRCA type, immune response, differentiation, and drug response. Using supervised principal component regression, 59 genes involved in at least one of these 17 pathways were selected as genomic predictors. The prediction accuracy of patient pCR was 0.70, sensitivity was 0.71, and specificity was 0.70. Conclusion: By combining knowledge-based and data-driven methods, we have identified 59 genes from breast cancer cell lines as pharmacogenomic predictors of drug response to TFAC. These results support the viability of using breast cancer cell lines to predict breast cancer patient response to chemotherapy. Further functional study of these pharmacogenomic predictors will extend our understanding of individual drug response and facilitate personalized treatment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-08-02.

Abstract P2-09-10: Feasibility Assessment of Pharmacogenomic Predictors Developed from Breast Cancer Cell Lines To Predict Breast Cancer Patient Pathological Response in Neoadjuvant Chemotherapy

Background: Studies of developing pharmacogenomic predictors from cancer cell lines to predict cancer patient clinical response and outcome to chemotherapy have yielded both positive and negative results. The variability in these results may arise from the noise inherent of microarray technology as well as the small sample size of in cell line studies. Therefore, it is greatly needed to evaluate the feasibility of using cell lines to develop pharmacogenomic predictors of patient pathological response. Material and Methods: Thirty breast cancer cell lines were exposed to 10 concentrations of paclitaxel-5-fluorouracil-doxorubicin-cyclophosphamide (TFAC) to measure in vitro chemosensitivity. Two independent and publicly available microarray datasets (Hoeflich and Neve) on these breast cancer cell lines together with the chemosensitivity results were used to identify pharmacogenomic predictors from each dataset. Two independent clinical trials (Hess and Popovici) with publically available data, having 130 and 100 patients respectively, were used as test sets to validate the accuracy of the pharmacogenomic predictors. All patients received TFAC as neoadjuvant therapy and the gene expression profiles of patients were assessed before receiving chemotherapy treatment. The patient's pathological complete response (pCR) was determined after treatment to evaluate the chemotherapy efficacy.

The pharmacogenomic predictors developed from each of the cell line studies were evaluated for their ability to predict patient pCR in each of the clinical trials using the supervised principle component regression method.

Results: The pharmacogenomic predictors identified from the Hoeflich and Neve cell line data (training sets) predicted pCR of the patients in the two clinical trials (test sets) with 64%-68% accuracy, 70%-87% sensitivity, and 60%-67% specificity when 100 genes were selected as pharmacogenomic predictors (Table 1).

Conclusions: The four independent prediction results generated in this study demonstrate the feasibility of using breast cancer cell lines to identify pharmacogenomic predictors of response to chemotherapy treatment for breast cancer patients. Future studies will examine the use of drug responses from primary cultures of patient tumors to develop pharmacogenomic predictors of breast cancer patient responses to chemotherapy treatment.

Table 1. Prediction of breast cancer patients’ pCR by pharmacogenomic predictors derived from breast cancer cell lines.

Diffusion-Weighted MRI in Predicting the Efficacy of Neoadjuvant Chemotherapy of Breast Cancer

Objective: To approach the apparent diffusion coefficient(ADC) obtained on diffusion weighted imaging (DWI) in predicting the response of breast cancer to neoadjuvant chemotherapy.Methods: 53 locally advanced breast cancer patients participated in this prospective study on neoadjuvant chemotherapy. All patients were treated with weekly neoadjuvant paclitaxel plus carboplatin for 4 cycles. DWI and ADC value were examined before chemotherapy(the first time point), after the first and the forth cycle of chemotherapy(the second and the third time point). Patients were categorized as high responders if their ADC at the second time point were higher by 2 times the standard deviation than the mean pre-chemotherapy ADC, and otherwise the patients were considered as low responders. Logistic regression was conducted to examine the independent factors predictive of clinical complete response(CR) and pathologic complete response(pCR).Results: CR was documented in 13 patients (24.5%); partial response in 36 patients (67.9%); stable disease in 4 patients (7.5%) and no patient had progressive disease. 11 patients(20.8%) have achieved pCR. There was a strong positive correlation between the percentage changes in ADC value at the third time points and the degree of the tumor reduction. A significant increase in ADC value was observed at the second time point compared with the first time point (1.104±0.117×10-3mm2/s, 1.220±0.158×10-3mm2/s, P&lt;0.001), while the decrease of the longest diameter of the tumors measured by physical examination, ultrasound or MRI or the tumor volumn measured by MRI were not (P&gt;0.05). Logistic regression revealed that percentage changes of ADC value at the second time point were significantly associated with CR(P=0.022, hazard ratio[HR] =1.08, 95% confidence interval[CI]: 1.01∼1.16) and pCR(P=0.022, HR =1.11, 95%CI: 1.02∼1.21). The AUC value of the receiver operating characteristic curve were 0.721(95%CI: 0.512∼0.931, P=0.017) and 0.775(95%CI: 0.598∼0.952, P=0.005) in the two diagnostic tests for CR and pCR, and the sensitivity and specificity were 76.9%, 63.6% and 77.5%, 90.5%, respectively. According to categorizing system described above, 10 patients(18.9%) were considered as high responders and 43 patients(81.1%) low responders. 7 patients(70%) of the high responders have achieved clinical CR and pCR while for the low responders there were only 6 patients(14.0%) and 4 patients (9.3%) proven to have CR and pCR. The difference have both reached statistical significance(P=0.001, P&lt;0.001). Logistic regression confirmed that the categorizing system was independently predictive of CR(P=0.006, HR=42.26, 95%CI: 2.86∼624.08) and pCR(P=0.013, HR=25.19, 95%CI: 2.00∼318.91). Taking this categorizing system as a dignostic test, the sensitivity and specificity were 53.8% and 92.5% for CR and 63.6% and 92.9% for pCR, respectively.Conclusions: The change of ADC value obtained on DWI after the first cycle of neoadjuvant chemotherapy occured prior to the morphologic changes of the tumor and at this time ADC value could to some extent predict the efficacy of neoadjuvant chemotherapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4025.

Estrogen Receptor Expression: Possible Predictor of Pathological Complete Response to Neoadjuvant Chemotherapy in Locally Advanced Breast Cancer Patients

BackgroundEstrogen receptor(ER) status has been found to correlate inversely to pathologic complete response (pCR) rates of neoadjuvant chemotherapy(NAC) of breast cancer. However, not all ER-positive breast cancer respond equally to NAC. The present study aimed to determine the relationship between different ER expression level with pCR in locally advanced breast cancer(LABC) patients who have received NAC.MethodsA retrospective study of 332 female unilateral LABC patients undergoing NAC was performed. All patients were confirmed as invasive breast cancer before treated with NAC, including VE (vinorelbine, epirubicin), CEF (cyclophosphamide, epirubicin, fluorouracil) and PCb regimen (paclitaxel, carboplatin). All patients underwent radical surgery and pCR was defined as the absence of invasive breast cancer in both breast and axillary lymph nodes. ER status were checked using the established immunohistochemical(IHC) method and defined as negative, weakly positive(1+), medium positive(2+) and strongly positive(3+). Binary logistic regression was performed to determine the independent predictors of pCR.ResultsER negativity, 1+, 2+ and 3+ were found in 156, 108, 37 and 31 patients, of which 42(26.9%), 21(19.4%), 3(8.1%) and 1 patients(3.2%) have achieved pCR. Binary logistic regression showed that different ER expression level(P=0.021) and HER2 status(P=0.007, hazard ratio[HR] =2.557, 95% confidence interval[CI]: 1.297∼5.038) were significantly associated with the pCR rates. pCR was much more likely to occur in patients with ER-negative(P=0.024, HR =13.119, 95% CI: 1.402∼122.774) or ER 1+(P=0.025, HR=12.928, 95% CI: 1.388∼120.390) tumors than those with ER 3+ tumors.ConclusionER weekly positive patients also gain considerable benefit from NAC, which is probably less effective in ER strongly positive patients in terms of pCR.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1104.

Prediction of Response to Paclitaxel by ChemoFx assay Correlates with Estrogen Receptor Status and Changes in Apoptosis Pathway in Human Breast Cancers

Background: Paclitaxel belongs to the taxane family of therapeutics, which have emerged as critically important drugs for breast cancer treatment. In addition to inhibiting cell growth by interfering with microtubule disassembly, its mechanism of action also includes induction of apoptosis. Recent studies suggest that besides being a key predictor for endocrine therapy response, Estrogen Receptor (ER) status also influences sensitivity of breast cancer to paclitaxel, with ER negative tumors being more responsive to the drug.Methods: The ChemoFx live cell chemoresponse assay was performed on 25 breast cancer cell lines (10 ER+ and 15 ER-). These cells were treated with a range of 10 doses of paclitaxel for 72 hours before DAPI staining of nuclei and counting. AUC (Area Under Curve) values were calculated and additional statistical analysis was performed on the resulting dose-response curves. Differential gene expression analysis was conducted to compare ER+ (n=82) and ER- (n=51) breast cancer patients using a public Microarray database. In addition, 2 of the 25 breast cancer cell lines, T47D (ER+) and SKBR3 (ER-), were treated with paclitaxel, lysed, and analyzed with Western blotting to detect cleaved caspase-3 and cleaved PARP expression, with beta-actin employed as a normal control.Results: The ChemoFx assay results revealed that none of the ER+ cells were categorized as R (responsive) to paclitaxel, with seven NR (non-responsive) and one IR (intermediate responsive). On the contrary, of the 15 ER- cell lines, three were categorized as R, only four were categorized as NR, and eight were categorized as IR. Statistical analysis suggested that paclitaxel responsiveness based on ChemoFx assay correlates with ER status (Chi-square test, p&lt;0.05), with ER- breast tumors being more responsive to paclitaxel. Microarray analysis revealed differential expressions of genes implicated in the apoptosis pathway (q&lt; 0.05) in ER+ and ER- breast cancers. Western blot analysis showed that paclitaxel induced cleaved caspase-3 and cleaved PARP expressions, both of which are indicators of activation of apoptosis, in SKBR3 cells (ER-), but not in T47D cells (ER+).Conclusions: ER status appears to predict in part, the response of breast cancer cells to paclitaxel as determined by the ChemoFx assay. ER-negative breast cancer cells are more likely to be responsive, which is consistent with established clinical findings. Our assay also distinguishes between NR/IR and R to paclitaxel within the ER- population. Similar ChemoFx assays are being performed on primary cultures from ER+ and ER- breast cancer patient specimens. Results from RNA microarray and Western blot analyses indicate that differences in gene expression in the apoptosis pathway, and in activation of apoptosis pathway, namely changes in expressions of cleaved PARP and cleaved caspase-3 in response to paclitaxel, may explain differences in the responsiveness of ER+ and ER- breast cancers to paclitaxel. This also suggests a potential role of cleaved PARP and cleaved caspase-3 as biomarkers in addition to ER for prediction of paclitaxel responsiveness in breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2028.