Correlation of drug response with the ATP tumorchemosensitivity assay in primary FIGO stage III ovarian cancer

Fibroblast growth factor signalling influences homologous recombination-mediated DNA damage repair to promote drug resistance in ovarian cancer

BACKGROUND

Ovarian cancer patients frequently develop chemotherapy resistance, limiting treatment options. We have previously shown that individuality in fibroblast growth factor 1 (FGF1) expression influences survival and chemotherapy response.

METHODS

We used MTT assays to assess chemosensitivity to cisplatin and carboplatin following shRNA-mediated knockdown or heterologous over-expression of FGF1 (quantified by qRT-PCR and immunoblot analysis), and in combination with the FGFR inhibitors AZD4547 and SU5402, the ATM inhibitor KU55933 and DNA-PK inhibitor NU7026. Immunofluorescence microscopy was used to quantify the FGF1-dependent timecourse of replication protein A (RPA) and γH2AX foci formation.

RESULTS

Pharmacological inhibition of FGF signalling reversed drug resistance in immortalised cell lines and in primary cell lines from drug-resistant ovarian cancer patients, while FGF1 over-expression induced resistance. Ataxia telangiectasia mutated (ATM) phosphorylation, but not DNA adduct formation was FGF1 dependent, following cisplatin or carboplatin challenge. Combining platinum drugs with the ATM inhibitor KU55933, but not with the DNA-PK inhibitor NU7026 re-sensitised resistant cells. FGF1 expression influenced the timecourse of damage-induced RPA and γH2AX nuclear foci formation.

CONCLUSION

Drug resistance arises from FGF1-mediated differential activation of high-fidelity homologous recombination DNA damage repair. FGFR and ATM inhibitors reverse platinum drug resistance, highlighting novel combination chemotherapy approaches for future clinical trial evaluation.

Benefits of functional assays in personalized cancer medicine: more than just a proof-of-concept

As complex and heterogeneous diseases, cancers require a more tailored therapeutic management than most pathologies. Recent advances in anticancer drug development, including the immuno-oncology revolution, have been too often plagued by unsatisfying patient response rates and survivals. In reaction to this, cancer care has fully transitioned to the “personalized medicine” concept. Numerous tools are now available tools to better adapt treatments to the profile of each patient. They encompass a large array of diagnostic assays, based on biomarkers relevant to targetable molecular pathways. As a subfamily of such so-called companion diagnostics, chemosensitivity and resistance assays represent an attractive, yet insufficiently understood, approach to individualize treatments. They rely on the assessment of a composite biomarker, the ex vivo functional response of cancer cells to drugs, to predict a patient's outcome. Systemic treatments, such as chemotherapies, as well as targeted treatments, whose efficacy cannot be fully predicted yet by other diagnostic tests, may be assessed through these means. The results can provide helpful information to assist clinicians in their decision-making process. We explore here the most advanced functional assays across oncology indications, with an emphasis on tests already displaying a convincing clinical demonstration. We then recapitulate the main technical obstacles faced by researchers and clinicians to produce more accurate, and thus more predictive, models and the recent advances that have been developed to circumvent them. Finally, we summarize the regulatory and quality frameworks surrounding functional assays to ensure their safe and performant clinical implementation. Functional assays are valuable in vitro diagnostic tools that already stand beyond the “proof-of-concept” stage. Clinical studies show they have a major role to play by themselves but also in conjunction with molecular diagnostics. They now need a final lift to fully integrate the common armament used against cancers, and thus make their way into the clinical routine.

Predicting response to platinum and non-platinum drugs through bioluminescence resonance energy transfer (BRET) based bio-molecular interactions in platinum resistant epithelial ovarian cancer

Therapy induced rewiring of signalling networks often lead to acquirement of platinum-resistance, thereby necessitating the use of non-platinum agents as second-line treatment particularly for epithelial ovarian cancer (EOC). A prior subject-specific assessment can guide the choice of optimal non-platinum agent/s and possible targeted therapeutic/s. Assessment of protein-protein interactions are superior to simple cytotoxicity assays to determine therapeutic efficacy and associated molecular responses. Utilizing improved PIP3-AKT and ERK1/2 activation Bioluminescence Resonance Energy Transfer (BRET) sensors, we report chemotherapy-induced ERK1/2 activation predominantly in cisplatin-paclitaxel resistant EOC cells and increased activation of both ERK1/2 and AKT in malignant ascites derived cancer cells from platinum-resistant patients but not from treatment-naive or platinum-sensitive relapse patients. Further, majority of the non-platinum drugs except irinotecan increased ERK1/2 activation in platinum-taxol resistant cells as observed by live-cell BRET assessment which were associated with p90RSK1/2 and BAD activation along with upregulation of multidrug transporter gene ABCC1 and cell survival genes like cyclin D1 and Bcl2. Interestingly, only irinotecan was able to sensitize these resistant cells. Altogether, this first report of BRET based sensing of molecular pathway activations in platinum resistant cell lines and patient's derived cancer cells highlight the clinical potential of BRET sensors in management of therapy resistant cancer.

Tumor Chemosensitivity Assays Are Helpful for Personalized Cytotoxic Treatments in Cancer Patients

Tumor chemosensitivity assays (TCAs), also known as drug response assays or individualized tumor response tests, have been gaining attention over the past few decades. Although there have been strong positive correlations between the results of these assays and clinical outcomes, they are still not considered routine tests in the care of cancer patients. The correlations between the assays' results (drug sensitivity or resistance) and the clinical evaluations (e.g., response to treatment, progression-free survival) are highly promising. However, there is still a need to design randomized controlled prospective studies to secure the place of these assays in routine use. One of the best ideas to increase the value of these assays could be the combination of the assay results with the omics technologies (e.g., pharmacogenetics that gives an idea of the possible side effects of the drugs). In the near future, the importance of personalized chemotherapy is expected to dictate the use of these omics technologies. The omics relies on the macromolecules (Deoxyribonucleic acid -DNA-, ribonucleic acid -RNA-) and proteins (meaning the structure) while TCAs operate on living cell populations (meaning the function). Therefore, wise combinations of TCAs and omics could be a highly promising novel landscape in the modern care of cancer patients.

Exploring the Potential of Drug Response Assays for Precision Medicine in Ovarian Cancer

One of the major challenges in the treatment of cancer are differential responses of patients to existing standard of care anti-cancer drugs. These differential responses may, in part, be due to a diverse range of genomic, epigenomic, proteomic, and metabolic alterations among individuals suffering from the same type of cancer. Precision medicine is an emerging approach in cancer therapeutics that takes into account specific molecular alterations, environmental factors as well as lifestyle of individual patients. This approach allows clinicians and researchers to select or predict treatments that would most likely benefit the patient based on their individual tumor characteristics. One class of precision medicine tools are predictive, in vitro drug-response assays designed to test the sensitivity of patient tumor cells to existing or novel therapies. These assays have the potential to rapidly identify the most effective treatments for cancer patients and thus hold great promise in the field of precision medicine. In this review, we have highlighted several drug-response assays developed in ovarian cancer and discussed the current challenges and future prospects of these assays in the clinical management of this disease.

Chemotherapy sensitivity testing on ovarian cancer cells isolated from malignant ascites

BACKGROUND

In epithelial ovarian cancer (EOC), 15-20% of the tumors do not respond to first-line chemotherapy (paclitaxel with platinum-based therapy), and in recurrences this number increases. Our aim is to determine the feasibility of cell proliferation assays of tumor cells isolated from malignant ascites to predict in vitro chemotherapy sensitivity, and to correlate these results with clinical outcome.

MATERIALS AND METHODS

Ascites was collected from twenty women with advanced EOC. Cell samples were enriched for tumor cells and EOC origin was confirmed by intracellular staining of CK7, surface staining of CA125 and EpCAM, and HE4 gene expression. In vitro sensitivity to chemotherapy was determined in cell proliferation assays using intracellular ATP content as an indirect measure of cell number. In vitro drug response was quantified by calculation of the drug concentration at which cell growth was inhibited with 50%. Clinical outcome was determined using post-treatment CA125 level.

RESULTS

Cell samples of twenty patients were collected, of which three samples that failed to proliferate were excluded in the analysis (15%). Three other samples were excluded, because clinical outcome could not be determined correctly. In twelve of the fourteen remaining cases (86%) in vitro drug sensitivity and clinical outcome corresponded, while in two samples (14%) there was no correspondence.

CONCLUSIONS

Our study demonstrates the feasibility of drug sensitivity tests using tumor cells isolated from ascites of advanced EOC patients. Larger observational studies are required to confirm the correlation between the in vitro sensitivity and clinical outcome.

A Three-dimensional Ex Vivo Viability Assay Reveals a Strong Correlation Between Response to Targeted Inhibitors and Mutation Status in Melanoma Lymph Node Metastases

Although clinical management of melanoma has changed considerably in recent years, intrinsic treatment resistance remains a severe problem and strategies to design personal treatment regimens are highly warranted. We have applied a three-dimensional (3D) ex vivo drug efficacy assay, exposing disaggregated cells from 38 freshly harvested melanoma lymph node metastases and 21 patient derived xenografts (PDXs) to clinical relevant drugs for 7 days, and examined its potential to evaluate therapy response. A strong association between Vemurafenib response and BRAF mutation status was achieved (P < .0001), while enhanced viability was seen in some NRAS mutated tumors. BRAF and NRAS mutated tumors responded comparably to the MEK inhibitor Cobimetinib. Based on the ex vivo results, two tumors diagnosed as BRAF wild-type by routine pathology examinations had to be re-evaluated; one was subsequently found to have a complex V600E mutation, the other a double BRAF mutation (V600E/K601 N). No BRAF inhibitor resistance mechanisms were identified, but PIK3CA and NF1 mutations were identified in two highly responsive tumors. Concordance between ex vivo drug responses using tissue from PDXs and corresponding patient tumors demonstrate that PDX models represent an indefinite source of tumor material that may allow ex vivo evaluation of numerous drugs and combinations, as well as studies of underlying molecular mechanisms. In conclusion, we have established a rapid and low cost ex vivo drug efficacy assay applicable on tumor tissue from patient biopsies. The 3D/spheroid format, limiting the influence from normal adjacent cells and allowing assessment of drug sensitivity to numerous drugs in one week, confirms its potential as a supplement to guide clinical decision, in particular in identifying non-responding patients.

Adenosine triphosphate-based chemotherapy response assay predicts long-term survival of primary epithelial ovarian cancer

OBJECTIVE

The aim of this study is to analyze the long-term relapse-free survival and overall survival outcomes of primary ovarian cancer patients using adenosine triphosphate-based chemotherapy response analysis.

METHODS

In total, 162 primary epithelial ovarian cancer patients who underwent chemotherapy response assay for carboplatin, cisplatin, and paclitaxel by adenosine triphosphate-based chemotherapy response analysis prior to chemotherapy between December 2006 and November 2016 were retrospectively reviewed. Chemosensitivity with single or combined three agents and clinical characteristics of patients were studied to understand their correlation with long-term relapse-free survival and overall survival.

RESULTS

Median follow-up time was 61.4 (range 1 - 130) months. Univariate analysis showed the paclitaxel-sensitive group (HR = 0.625, 95%CI = 0.393 to 0.994), combined carboplatin and paclitaxel-sensitive group (HR = 0.574, 95%CI = 0.352 to 0.937), and combined carboplatin, cisplatin, and paclitaxel-sensitive group (HR = 0.489, 95%CI = 0.295 to 0.810) were highly associated with better relapse-free survival than their corresponding non-sensitive groups. The carboplatin-sensitive group (HR = 0.533, 95%CI = 0.303 to 0.939), cisplatin-sensitive group (HR = 0.433. 95%CI = 0.251 to 0.748), and combined carboplatin- and cisplatin-sensitive group (HR = 0.286, 95%CI = 0.142 to 0.576) were highly associated with better overall survival than their corresponding non-sensitive groups. Combined carboplatin, cisplatin, and paclitaxel chemosensitivity, together with International Federation of Gynecology and Obstetrics (FIGO) stage were independent predictors for relapse-free survival. Single or combined chemosensitivity of cisplatin and/or carboplatin, together with residual tumor size and FIGO stage, were significant independent predictors for overall survival on a multivariate hazard model.

CONCLUSION

Paclitaxel sensitivity is a prognostic factor of long-term relapse-free survival in patients with epithelial ovarian cancer, but platinum sensitivity is a more important prognostic factor for long-term overall survival.

Mathematical model of T-cell lymphoblastic lymphoma: disease, treatment, cure or relapse of a virtual cohort of patients

T lymphoblastic lymphoma (T-LBL) is a rare type of lymphoma with a good prognosis with a remission rate of 85%. Patients can be completely cured or can relapse during or after a 2-year treatment. Relapses usually occur early after the remission of the acute phase. The median time of relapse is equal to 1 year, after the occurrence of complete remission (range 0.2-5.9 years) (Uyttebroeck et al., 2008). It can be assumed that patients may be treated longer than necessary with undue toxicity.The aim of our model was to investigate whether the duration of the maintenance therapy could be reduced without increasing the risk of relapses and to determine the minimum treatment duration that could be tested in a future clinical trial.We developed a mathematical model of virtual patients with T-LBL in order to obtain a proportion of virtual relapses close to the one observed in the real population of patients from the EuroLB database. Our simulations reproduced a 2-year follow-up required to study the onset of the disease, the treatment of the acute phase and the maintenance treatment phase.

Identification of proteins associated with paclitaxel resistance of epithelial ovarian cancer using iTRAQ-based proteomics

Chemotherapy is an important adjuvant therapy for epithelial ovarian cancer (EOC). The main cause of chemotherapy failure in EOC is paclitaxel resistance. The present study aimed to identify novel biomarkers to predict chemosensitivity to paclitaxel and improve our understanding of the molecular mechanisms underlying paclitaxel resistance in EOC. In the present study, the heterogeneity of EOC was evaluated by adenosine triphosphate-tumor chemosensitivity assay (ATP-TCA) in vitro. Fresh samples were collected from 54 EOC cases during cytoreductive surgery. Tumor cells were isolated, cultured, and tested for sensitivity to paclitaxel. Proteins that were differentially expressed between paclitaxel-resistant tissues and paclitaxel-sensitive tissues were identified via isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis. Two upregulated proteins, plexin domain containing 2 (Plxdc2) and cytokeratin 7 (CK7), were selected to verify the iTRAQ method using western blot analysis in EOC tissues with different chemosensitivities (sensitive, weakly sensitive and resistant). There was notable heterogeneity of chemosensitivity in the EOC specimens. Highly to mildly-differentiated or early-stage (I/II) EOC specimens had decreased sensitivity to paclitaxel compared with specimens with low differentiation (P<0.05) or an advanced stage (III; P<0.05), respectively. A total of 496 significantly differentially expressed proteins, including 263 that were downregulated (P<0.05) and 233 that were upregulated (P<0.05) in paclitaxel-resistant tissues compared with paclitaxel-sensitive tissues, were identified using iTRAQ in combination with LC-MS/MS. The expression levels of two proteins associated with paclitaxel resistance, Plxdc2 and CK7, were further validated by western blotting, which revealed that they were upregulated in the paclitaxel-resistant tissues. The present study determined candidate proteins associated with paclitaxel resistance in EOC. Plxdc2 and CK7 may be potential makers for distinguishing patients with paclitaxel-resistant EOC from those with paclitaxel-sensitive EOC.

Predictive Value of Ex Vivo Chemosensitivity Assays for Individualized Cancer Chemotherapy: A Meta-Analysis

Current treatment strategies for chemotherapy of cancer patients were developed to benefit groups of patients with similar clinical characteristics. In practice, response is very heterogeneous between individual patients within these groups. Precision medicine can be viewed as the development toward a more fine-grained treatment stratification than what is currently in use. Cell-based drug sensitivity testing is one of several options for individualized cancer treatment available today, although it has not yet reached widespread clinical use. We present an up-to-date literature meta-analysis on the predictive value of ex vivo chemosensitivity assays for individualized cancer chemotherapy and discuss their current clinical value and possible future developments.

ABCB1 (MDR1) induction defines a common resistance mechanism in paclitaxel- and olaparib-resistant ovarian cancer cells

BACKGROUND

Clinical response to chemotherapy for ovarian cancer is frequently compromised by the development of drug-resistant disease. The underlying molecular mechanisms and implications for prescription of routinely prescribed chemotherapy drugs are poorly understood.

METHODS

We created novel A2780-derived ovarian cancer cell lines resistant to paclitaxel and olaparib following continuous incremental drug selection. MTT assays were used to assess chemosensitivity to paclitaxel and olaparib in drug-sensitive and drug-resistant cells±the ABCB1 inhibitors verapamil and elacridar and cross-resistance to cisplatin, carboplatin, doxorubicin, rucaparib, veliparib and AZD2461. ABCB1 expression was assessed by qRT-PCR, copy number, western blotting and immunohistochemical analysis and ABCB1 activity assessed by the Vybrant and P-glycoprotein-Glo assays.

RESULTS

Paclitaxel-resistant cells were cross-resistant to olaparib, doxorubicin and rucaparib but not to veliparib or AZD2461. Resistance correlated with increased ABCB1 expression and was reversible following treatment with the ABCB1 inhibitors verapamil and elacridar. Active efflux of paclitaxel, olaparib, doxorubicin and rucaparib was confirmed in drug-resistant cells and in ABCB1-expressing bacterial membranes.

CONCLUSIONS

We describe a common ABCB1-mediated mechanism of paclitaxel and olaparib resistance in ovarian cancer cells. Optimal choice of PARP inhibitor may therefore limit the progression of drug-resistant disease, while routine prescription of first-line paclitaxel may significantly limit subsequent chemotherapy options in ovarian cancer patients.

ABCB1 (MDR1) induction defines a common resistance mechanism in paclitaxel- and olaparib-resistant ovarian cancer cells

BACKGROUND

Clinical response to chemotherapy for ovarian cancer is frequently compromised by the development of drug-resistant disease. The underlying molecular mechanisms and implications for prescription of routinely prescribed chemotherapy drugs are poorly understood.

METHODS

We created novel A2780-derived ovarian cancer cell lines resistant to paclitaxel and olaparib following continuous incremental drug selection. MTT assays were used to assess chemosensitivity to paclitaxel and olaparib in drug-sensitive and drug-resistant cells±the ABCB1 inhibitors verapamil and elacridar and cross-resistance to cisplatin, carboplatin, doxorubicin, rucaparib, veliparib and AZD2461. ABCB1 expression was assessed by qRT-PCR, copy number, western blotting and immunohistochemical analysis and ABCB1 activity assessed by the Vybrant and P-glycoprotein-Glo assays.

RESULTS

Paclitaxel-resistant cells were cross-resistant to olaparib, doxorubicin and rucaparib but not to veliparib or AZD2461. Resistance correlated with increased ABCB1 expression and was reversible following treatment with the ABCB1 inhibitors verapamil and elacridar. Active efflux of paclitaxel, olaparib, doxorubicin and rucaparib was confirmed in drug-resistant cells and in ABCB1-expressing bacterial membranes.

CONCLUSIONS

We describe a common ABCB1-mediated mechanism of paclitaxel and olaparib resistance in ovarian cancer cells. Optimal choice of PARP inhibitor may therefore limit the progression of drug-resistant disease, while routine prescription of first-line paclitaxel may significantly limit subsequent chemotherapy options in ovarian cancer patients.

Correlation of Early Recurrence With In Vitro Adenosine Triphosphate Based Chemotherapy Response Assay in Pancreas Cancer With Postoperative Gemcitabine Chemotherapy

INTRODUCTION

Gemcitabine-based regimens represent the standard systemic first line treatment in patients after pancreatic resection. However, the clinical impact of gemcitabine varies significantly in individuals because of chemoresistance. An in vitro adenosine triphosphate based chemotherapy response assay (ATP-CRA) was designed to evaluate the sensitivity of cancer cells to various chemotherapeutic agents. This study investigated the correlation between in vitro gemcitabine sensitivity of tumor cells and early recurrence after curative resection.

METHOD

From January 2007 to December 2010, the ATP-CRA for gemcitabine was tested in 64 patients surgically treated for pancreas cancer at Gangnam Severance Hospital, Seoul, Korea. We analyzed the relationship between chemosensitivity and early systemic recurrence in patients with pancreas cancer to predict disease-free survival (DFS) after curative resection in pancreas cancer.

RESULT

The mean cell death rate (CDR) was 20.0 (±14.5) and divided into two groups according to the mean values of the CDR. Lymphovascular invasion was more frequently shown in gemcitabine resistance group without statistical significance. In univariate and multivariate analysis, advanced tumor stage and gemcitabine sensitive group (CDR ≥ 20) were identified as independent prognostic factors for DFS.

CONCLUSIONS

Gemcitabine sensitivity measured by ATP-CRA was well correlated with in vivo drug responsibility to predict early recurrence following gemcitabine-based adjuvant chemotherapy in patients with pancreas cancer.

Special Technologies for Ex Vivo Analysis of Cancer

BACKGROUND

Predictive assays for cancer treatment are not new technology, but they have failed to meet the criteria necessary for standardized use in clinical decision-making.

METHODS

The authors summarize the use of predictive assays and the challenges and values associated with these assays in the clinical setting.

RESULTS

Predictive assays commercially available in the clinical setting are not standardized, have significant obstacles to overcome, and cannot be relied upon by health care professionals due to the limited value these assays provide to the decision-making process for the treatment of patients.

CONCLUSIONS

A method that more closely recapitulates the human tumor microenvironment and accurately predicts response with high reproducibility would be beneficial to patient outcomes and quality of life.

Mutation analysis of EGFR and its correlation with the HPV in Indian cervical cancer patients

Cervical cancer is a major cause of morbidity and mortality particularly in developing countries. Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene is associated with increased sensitivity to tyrosine kinase inhibitors (TKIs). In this study, the presence of EGFR mutations in cervical cancer and its correlation with HPV were identified. EGFR mutations were found in 31 out of 95 patients (32.63 %). Results showed the presence of EGFR mutations in 5.263 % of patients in exon 19. In exon 20, mutations were predominant in 25.26 % patients. While in exon 21, 8.421 % of patients had mutations. HPV, which is associated with cervical cancer development, was found in 95.78 % (HPVL1), 92.63 % (HPV16), and 3.15 % (HPV18) of patients. No correlation was found between HPV16 and EGFR mutations (p = 0.0616). Overall, mutations like V742R, Q787Q, Q849H, E866E, T854A, L858R, E872Q, and E688Q were found. Next, impact of TKI inhibitor (gefitinib) was checked with respect to presence or absence of mutation considering Q787Q mutation in exon 20 (G/A genotype) which is present in 25.2 % patients. Mutated cervical cancer cell lines showed higher sensitivity to gefitinib. Overall, this study suggests the importance of mutations in EGFR gene and indicates their relevance with respect to TKIs treatment in Indian cervical cancer patients.

Prediction of Cancer Drug Resistance and Implications for Personalized Medicine

Drug resistance still impedes successful cancer chemotherapy. A major goal of early concepts in individualized therapy was to develop in vitro tests to predict tumors’ drug responsiveness. We have developed an in vitro short-term test based on nucleic acid precursor incorporation to determine clinical drug resistance. This test detects inherent and acquired resistance in vitro and transplantable syngeneic and xenografted tumors in vivo. In several clinical trials, clinical resistance was predictable with more than 90% accuracy, while drug sensitivity was detected with less accuracy (~60%). Remarkably, clinical cross-resistance to numerous drugs (multidrug resistance, broad spectrum resistance) was detectable by a single compound, doxorubicin, due to its multifactorial modes of action. The results of this predictive test were in good agreement with predictive assays of other authors. As no predictive test has been established as yet for clinical diagnostics, the identification of sensitive drugs may not reach sufficiently high reliability for clinical routine. A meta-analysis of the literature published during the past four decades considering test results of more than 15,000 tumor patients unambiguously demonstrated that, in the majority of studies, resistance was correctly predicted with an accuracy between 80 and 100%, while drug sensitivity could only be predicted with an accuracy of 50–80%. This synopsis of the published literature impressively illustrates that prediction of drug resistance could be validated. The determination of drug resistance was reliable independent of tumor type, test assay, and drug used in these in vitro tests. By contrast, chemosensitivity could not be predicted with high reliability. Therefore, we propose a rethinking of the “chemosensitivity” concept. Instead, predictive in vitro tests may reliably identify drug-resistant tumors. The clinical consequence imply to subject resistant tumors not to chemotherapy, but to other new treatment options, such as antibody therapy, adoptive immune therapy, hyperthermia, gene therapy, etc. The high accuracy to predict resistant tumors may be exploited to develop new strategies for individualized cancer therapy. This new concept bears the potential of a revival of predictive tests for personalized medicine.

In Vitro Adenosine Triphosphate-Based Chemotherapy Response Assay as a Predictor of Clinical Response to Fluorouracil-Based Adjuvant Chemotherapy in Stage II Colorectal Cancer

PURPOSE

We evaluated the usefulness of the in vitro adenosine triphosphate-based chemotherapy response assay (ATP-CRA) for prediction of clinical response to fluorouracil-based adjuvant chemotherapy in stage II colorectal cancer.

MATERIALS AND METHODS

Tumor specimens of 86 patients with pathologically confirmed stage II colorectal adenocarcinoma were tested for chemosensitivity to fluorouracil. Chemosensitivity was determined by cell death rate (CDR) of drug-exposed cells, calculated by comparing the intracellular ATP level with that of untreated controls.

RESULTS

Among the 86 enrolled patients who underwent radical surgery followed by fluorouracil-based adjuvant chemotherapy, recurrence was found in 11 patients (12.7%). The CDR ≥ 20% group was associated with better disease-free survival than the CDR < 20% group (89.4% vs. 70.1%, p=0.027). Multivariate analysis showed that CDR < 20% and T4 stage were poor prognostic factors for disease-free survival after fluorouracil-based adjuvant chemotherapy.

CONCLUSION

In stage II colorectal cancer, the in vitro ATP-CRA may be useful in identifying patients likely to benefit from fluorouracil-based adjuvant chemotherapy.

Heterogeneity of tumor chemosensitivity in ovarian epithelial cancer revealed using the adenosine triphosphate-tumor chemosensitivity assay

Ovarian cancer has a poor prognosis, primarily due to the heterogeneity in chemosensitivity among patients. In the present study, this heterogeneity was evaluated in ovarian epithelial cancer (OEC) using an in vitro adenosine triphosphate tumor chemosensitivity assay (ATP-TCA). Specimens were collected from 80 patients who underwent cytoreductive surgery. Viable ovarian cancer cells obtained from malignant tissues were tested for sensitivity to paclitaxel (PTX), carboplatin (CBP), topotecan (TPT), gemcitabine (GEM), docetaxel (TXT), etoposide, bleomycin and 4-hydroperoxycyclophosphamide using ATP-TCA. The sensitivity, specificity, positive predictive value and negative predictive value for the clinical chemotherapy sensitivity of OEC were 88.6, 77.8, 83 and 84.8%, respectively. PTX demonstrated the highest sensitivity of all agents tested (82.5% in all specimens, 85.7% in recurrent specimens), followed by CBP (58.8 and 60.7%, respectively). The sensitivities to PTX and docetaxel (P<0.001) were correlated, in addition to those of CBP, TPT and GEM (P<0.001). Early-stage (I/II) and high- to mildly-differentiated OEC specimens revealed a lower chemosensitivity than advanced-stage (III) or low-differentiated specimens, respectively. The present study indicated that ATP-TCA is an effective method for guiding the choice of chemotherapy drugs. Notable heterogeneity of chemosensitivity was observed in the OEC specimens.

Prediction of individual response to anticancer therapy: historical and future perspectives

Since the introduction of chemotherapy for cancer treatment in the early 20th century considerable efforts have been made to maximize drug efficiency and at the same time minimize side effects. As there is a great interpatient variability in response to chemotherapy, the development of predictive biomarkers is an ambitious aim for the rapidly growing research area of personalized molecular medicine. The individual prediction of response will improve treatment and thus increase survival and life quality of patients. In the past, cell cultures were used as in vitro models to predict in vivo response to chemotherapy. Several in vitro chemosensitivity assays served as tools to measure miscellaneous endpoints such as DNA damage, apoptosis and cytotoxicity or growth inhibition. Twenty years ago, the development of high-throughput technologies, e.g. cDNA microarrays enabled a more detailed analysis of drug responses. Thousands of genes were screened and expression levels were correlated to drug responses. In addition, mutation analysis became more and more important for the prediction of therapeutic success. Today, as research enters the area of -omics technologies, identification of signaling pathways is a tool to understand molecular mechanism underlying drug resistance. Combining new tissue models, e.g. 3D organoid cultures with modern technologies for biomarker discovery will offer new opportunities to identify new drug targets and in parallel predict individual responses to anticancer therapy. In this review, we present different currently used chemosensitivity assays including 2D and 3D cell culture models and several -omics approaches for the discovery of predictive biomarkers. Furthermore, we discuss the potential of these assays and biomarkers to predict the clinical outcome of individual patients and future perspectives.

Purinergic signalling and cancer

Receptors for extracellular nucleotides are widely expressed by mammalian cells. They mediate a large array of responses ranging from growth stimulation to apoptosis, from chemotaxis to cell differentiation and from nociception to cytokine release, as well as neurotransmission. Pharma industry is involved in the development and clinical testing of drugs selectively targeting the different P1 nucleoside and P2 nucleotide receptor subtypes. As described in detail in the present review, P2 receptors are expressed by all tumours, in some cases to a very high level. Activation or inhibition of selected P2 receptor subtypes brings about cancer cell death or growth inhibition. The field has been largely neglected by current research in oncology, yet the evidence presented in this review, most of which is based on in vitro studies, although with a limited amount from in vivo experiments and human studies, warrants further efforts to explore the therapeutic potential of purinoceptor targeting in cancer.

Glutathione S-transferase P1 (GSTP1) directly influences platinum drug chemosensitivity in ovarian tumour cell lines

Background:

Chemotherapy response in ovarian cancer patients is frequently compromised by drug resistance, possibly due to altered drug metabolism. Platinum drugs are metabolised by glutathione S-transferase P1 (GSTP1), which is abundantly, but variably expressed in ovarian tumours. We have created novel ovarian tumour cell line models to investigate the extent to which differential GSTP1 expression influences chemosensitivity.

Methods:

Glutathione S-transferase P1 was stably deleted in A2780 and expression significantly reduced in cisplatin-resistant A2780DPP cells using Mission shRNA constructs, and MTT assays used to compare chemosensitivity to chemotherapy drugs used to treat ovarian cancer. Differentially expressed genes in GSTP1 knockdown cells were identified by Illumina HT-12 expression arrays and qRT–PCR analysis, and altered pathways predicted by MetaCore (GeneGo) analysis. Cell cycle changes were assessed by FACS analysis of PI-labelled cells and invasion and migration compared in quantitative Boyden chamber-based assays.

Results:

Glutathione S-transferase P1 knockdown selectively influenced cisplatin and carboplatin chemosensitivity (2.3- and 4.83-fold change in IC₅₀, respectively). Cell cycle progression was unaffected, but cell invasion and migration was significantly reduced. We identified several novel GSTP1 target genes and candidate platinum chemotherapy response biomarkers.

Conclusions:

Glutathione S-transferase P1 has an important role in cisplatin and carboplatin metabolism in ovarian cancer cells. Inter-tumour differences in GSTP1 expression may therefore influence response to platinum-based chemotherapy in ovarian cancer patients.

In vitro chemoresponse assay based on the intrinsic subtypes in breast cancer

OBJECTIVE

In vitro chemotherapy response assays are not widely accepted in making decisions regarding cytotoxic drugs. To evaluate the usefulness of chemotherapy response assays in breast cancer, we compared the chemotherapy response assay results according to subtypes. Human epidermal growth factor receptor-2 and Ki67 associated with chemosensitivity were also analyzed.

METHODS

Four hundred and ninety-six patients were enrolled, and chemotherapy response assays based on adenosine triphosphate were performed in 500 tumors. Patients were classified as five subtypes: luminal A, luminal B/human epidermal growth factor receptor-2 negative, luminal B/human epidermal growth factor receptor-2 positive, human epidermal growth factor receptor-2 and triple negative. The cell death rate for various drugs was calculated.

RESULTS

The mean cell death rate of the luminal A subtype was the lowest, and the mean cell death rates of the human epidermal growth factor receptor-2 and triple-negative subtypes were the highest for all tested drugs, except 5-fluorouracil and methotrexate. The cell death rate differed significantly among the subtypes in the types of drugs (doxorubicin, epirubicin, paclitaxel, docetaxel, gemcitabine, vinorelbine and cisplatin). In triple-negative tumors, the mean cell death rate of cisplatin was the highest among the tested drugs, and which was not observed in the other subtypes. Human epidermal growth factor receptor-2 positive tumors are associated with higher cell death rates for anthracyclines. High Ki67 expression (a cutoff of 14%) was associated with a high response in several tested drugs including epirubicin, paclitaxel, docetaxel, gemcitabine, vinorelbine and cisplatin.

CONCLUSIONS

Our findings suggest that in vitro chemoresponse assays for breast tumors could effectively reflect the tumor response to chemotherapies observed in neoadjuvant settings.

Chemotherapeutic drug sensitivity of primary cultures of epithelial ovarian cancer cells from patients in relation to tumour characteristics and therapeutic outcome

BACKGROUND

A number of chemotherapeutic drugs are active in epithelial ovarian cancer (EOC) but so far choice of drugs for treatment is mostly empirically based. Testing of drug activity in tumour cells from patients might provide a rationale for a more individualised approach for drug selection.

MATERIAL AND METHODS

Sensitivity of EOC to chemotherapeutic drugs was analysed in 125 tumour samples from 112 patients using a short-term primary culture assay based on the concept of total cell kill. Sensitivity was related to tumour histology, treatment status and clinical tumour response.

RESULTS

For most EOC standard drugs serous high grade and clear cell EOC were the most sensitive subtypes and the mucinous tumours the most resistant subtype. Docetaxel, however, tended to show the opposite pattern. Samples from previously treated patients tended to be more resistant than those from treatment naïve patients. The activity of cisplatin correlated with that of other drugs with the exception of docetaxel. Tumour samples from two sites in the same patient at the same occasion showed similar cisplatin sensitivity in contrast to samples taken at different occasions. Samples from patients responding in the clinic to treatment were more sensitive to most drugs than samples from non-responding patients. At the individual patient level, drug sensitivity in vitro compared with clinical response showed sensitivities and specificities in the 83-100% and 55-83% ranges, respectively.

CONCLUSIONS

Assessment of EOC tumour cell drug sensitivity in vitro provides clinically relevant and potentially useful information for the optimisation of drug treatment.

Correlation between the molecular subtype of breast cancer and the in vitro adenosine triphosphate-based chemosensitivity assay

Purpose

The empirical use of a chemotherapy regimen shows different results in individual breast cancer patient treatment. Recent studies showed the effectiveness of the adenosine triphosphate-based chemotherapy response assay (ATP-CRA). However, little is known about the correlation between chemosensitivity and breast cancer molecular subtypes. Therefore, we investigated whether the result of ATP-CRA is associated with a molecular subtype of breast cancer.

Methods

Two hundred eighty-seven patients diagnosed with breast cancer and receiving ATP-CRA at Mokdong Hospital, Ewha Womans University between September 2007 and December 2010 were enrolled in this study. Hormone receptor status, HER2/neu expression, and results of chemosensitivity tests of the patients was analyzed.

Results

In all of four subtypes, the combination of two agents showed significant higher mean cell death rate than a single agent. Within the breast cancer cell lines in this study, the range of chemosensitivity response was very wide and varied for each patient. For this reason, the molecular subtype of breast cancer is inconclusive in choosing an effective chemotherapeutic agent and in vitro chemosensitivity test, prior to therapy, could be a useful method for planning chemotherapy for each patient.

Conclusion

Chemosensitivity response to anticancer agents was found to vary depending on the individual breast cancer patients. The molecular subtype of breast cancer is inconclusive to choose the effective chemotherapeutic agent and the in vitro chemosensitivity test, prior to therapy, could be more useful for planning chemotherapy for each patient.

Predicting platinum resistance in primary advanced ovarian cancer patients with an in vitro resistance index

PURPOSE

We aimed to identify primary platinum resistance in epithelial ovarian cancer (OC) patients with FIGO stage III-IV disease by an in vitro drug-response assay and to correlate the findings with clinical response. We considered whether neoadjuvant chemotherapy or anatomic sample site and tumor heterogeneity would influence the results.

METHODS

We combined the ATP-based tumor-chemosensitivity and the extreme drug resistance assays for testing of 85 biopsies from 58 patients. Tumors were classified as sensitive or resistant by a resistance index (RI). We did separate analyses of primary tumors and metastases and compared chemo-naïve samples with samples obtained after neoadjuvant chemotherapy. Results were analyzed for association with clinical platinum resistance, progression-free survival (PFS), and overall survival (OS).

RESULTS

RI · 250 predicted primary platinum resistance, without misclassification of sensitive patients. The test sensitivity for primary tumors was 15/15, specificity 3/10, negative predictive value 3/3, and positive predictive value 15/22. Patients with in vitro platinum-resistant samples had shorter PFS compared with patients with sensitive samples (3.4 vs. 10.0 months, p = 0.02). Comparing patient-matched primary and metastatic samples, there was about 1/3 mismatch in resistance. RI for platinum was lower in primary tumors exposed to neoadjuvant chemotherapy than in chemo-naïve tumors (p < 0.01).

CONCLUSIONS

This in vitro assay predicted primary platinum resistance, without misclassification of sensitive OC patients, and the results were significantly associated with PFS. We suggest that samples from primary tumor and metastatic samples have different responses to chemotherapy and that exposure to chemotherapy might induce in vitro platinum resistance.

Taxol-oligoarginine conjugates overcome drug resistance in-vitro in human ovarian carcinoma

OBJECTIVE

Multidrug resistance is the major cause of failure of many chemotherapeutic agents. While resistance can arise from several factors, it is often dominated by drug efflux mediated by P-glycoprotein (P-gp), a membrane-bound polysubstrate export pump expressed at high levels in resistant cells. While co-administration of pump inhibitors and a drug could suppress efflux, this two-drug strategy has not yet advanced to therapy. We recently demonstrated that the reversible attachment of a guanidinium-rich molecular transporter, polyarginine, to a drug provides a conjugate that overcomes efflux-based resistance in cells and animals. This study is to determine whether this strategy for overcoming resistance is effective against human disease.

METHODS

Tumor samples from ovarian cancer patients, both malignant ascites cells and dissociated solid tumor cells, were exposed to Taxol-oligoarginine conjugates designed to release free drug only after cell entry. Cell viability was determined via propidium-iodide uptake by flow cytometry. To analyze bystander effect, toxicity of the drug conjugates was also tested on peripheral blood leucocytes.

RESULTS

Human ovarian carcinoma specimens resistant to Taxol in vitro demonstrated increased sensitivity to killing by all Taxol-transporter conjugates tested. These studies also show that the drug conjugates were not significantly more toxic to normal human peripheral blood leukocytes than Taxol.

CONCLUSIONS

These studies with human tumor indicate that oligoarginine conjugates of known drugs can be used to overcome the efflux-based resistance to the drug, providing a strategy that could improve the treatment outcomes of patients with efflux-based drug-resistance.

Heterogeneity of chemosensitivity in esophageal cancer using ATP-tumor chemosensitivity assay

AIM

Current chemotherapy for esophageal cancer is conducted on the basis of empirical information from clinical trials, which fails to take into account the known heterogeneity of chemosensitivity between patients. This study was aimed to demonstrate the degree of heterogeneity of chemosensitivity in esophageal cancers.

METHODS

A total of 42 esophageal cancer specimens were collected. The heterogeneity of chemosensitivity in esophageal cancer specimens was examined using an ex vivo ATP-tumor chemosensitivity assay (ATP-TCA).

RESULTS

Thirty eight specimens produced evaluable results (90.5%). The most active single agent tested was nedaplatin, to which 28.9% of samples were sensitive. Combinations of chemotherapy agents exhibited much higher sensitivity: cisplatin + paclitaxel was sensitive in 16 of 38 (42.1%) of samples, while nedaplatin+paclitaxel was more effective, which was sensitive in 20 of 38 cases (52.6%).

CONCLUSION

There was a marked heterogeneity of chemosensitivity in esophageal cancer. Chemosensitivity testing may provide a practical method for testing new regimens before clinical trials in esophageal cancer patients.

Chemotherapy response assay test and prognosis for breast cancer patients who have undergone anthracycline- and taxane-based chemotherapy

PURPOSE

A chemotherapy response assay test is performed to evaluate the degree of tumor growth inhibition by a chemotherapeutic agent. Several studies have been done on its usefulness; however, to the best of our knowledge, only a few studies concerning the relationship between chemotherapy response assay test results and breast cancer patients' prognoses have been conducted. Thus, we performed this study to analyze this relationship.

METHODS

Among breast cancer patients who underwent curative surgery and neoadjuvant or adjuvant chemotherapy between August 2004 and December 2009, 102 were enrolled in this study. Chemotherapeutic regimens for patients were doxorubicin plus taxane or doxorubicin plus cyclophosphamide followed by taxane. We divided these patients into two groups (sensitive group [n=19] and resistant group [n=83]) and analyzed the relationship between chemosensitivity results and patient prognosis.

RESULTS

The sensitive group was associated with poor disease-free survival (DFS) (p=0.003) and overall survival (OS) (p<0.001). No significant differences were observed in tumor histology (p=0.548), tumor size (p=0.479), number of metastatic lymph nodes (p=0.326), histologic grade (p=0.077), or nuclear grade (p=0.216) between the two groups. However, in respect to molecular subtype, the HER2-positive type and triple negative breast cancer were more frequently observed in the sensitive group (p=0.001). In a univariate and multivariate analysis for DFS, doxorubicin sensitivity was significantly associated with a poor prognosis (p<0.05).

CONCLUSION

Better chemosensitivity results are associated with a poor prognosis in breast cancer patients who have undergone anthracycline- and taxane-based chemotherapy, however, examination of additional cases and the use of a longer study period are needed.

ATP assay-guided chemosensitivity testing for gemcitabine with biopsy specimens obtained from unresectable pancreatic cancer using endoscopic ultrasonography-guided fine-needle aspiration

OBJECTIVES

This study evaluates the feasibility of chemosensitivity testing by use of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) samples and determines the optimum cut-off value for gemcitabine.

METHODS

Thirty-four consecutive patients with unresectable pancreatic cancer were enrolled. Chemosensitivity (treated/control ratio: T/C ratio) was calculated as the quantity of adenosine triphosphate for a tumor treated with gemcitabine as a percentage of that for the control. To identify the cut-off value sufficient to predict 180 days of progression-free survival (PFS), the receiver operating characteristic curve and the corresponding area under the curve (AUC) were calculated.

RESULTS

The success of this assay was 88.2% (30/34); therefore, 30 patients were assessable and included in the population of analyzable patients.. The response was 6.7%. Median PFS was 96 days and median overall survival was 241 days, respectively. The cut-off value was determined as 74% (AUC, 0.745; p = 0.053; 95% CI 0.485-1.005). According to this cut-off value, we predicted 180 days PFS with a sensitivity and specificity of 71.4 and 91.3%, respectively. When patients were divided into two groups at T/C ratio 74%, a significant difference was found in PFS (median 77 vs. 205 days, p = 0.0036). Moreover, T/C ratio < 74% and decrease of CA19-9 were significant and independent prognostic factors by multivariate analysis.

CONCLUSION

Chemosensitivity testing by use of EUS-FNA samples in patients with unresectable pancreatic cancer is feasible. This definition emphasizes the possibility of selecting patients for whom favorable results from gemcitabine treatment can be expected.

Cell sensitivity assays: the ATP-based tumor chemosensitivity assay

The ATP-based tumor chemosensitivity assay (ATP-TCA) is a standardised system which can be adapted to a variety of uses with both cell lines and primary cell cultures. It has a strong track record in drug development, mechanistic studies of chemoresistance and as an aid to clinical decision-making. The method starts with the extraction of cells in suspension from continuous cell culture (for cell lines), malignant effusions or biopsy material. Enzymatic digestion is used to obtain cells from tumor tissue. The assay uses a serum-free medium and polypropylene plates to prevent the growth of non-neoplastic cells over a 6-day incubation period followed by detergent-based extraction of cellular ATP for measurement by luciferin-luciferase assay in a luminometer. The assay results are usually shown as percentage inhibition at each concentration tested, and can be used with suitable software to examine synergy between different anticancer agents.

In vitro adenosine triphosphate based chemotherapy response assay in gastric cancer

Purpose

The purpose of this study was to investigate the reliability and the clinical applicability of the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA) as a method of determining in vitro chemosensitivity in patients with gastric cancer.

Materials and Methods

A total of 243 gastric cancer tissue samples were obtained from gastrectomies performed between February 2007 and January 2010. We evaluated the effectiveness of the ATP-CRA assay in determining the chemosensitivity of gastric cancer specimens using eleven chemotherapeutic agents - etoposide, doxorubicin, epirubicin, mytomicin, 5-fluorouracil, oxaliplatin, irinotecan, docetaxel, paclitaxel, methotraxate, and cisplatin - for chemosensitivity studies using ATP-CRA. We assessed the failure rate, the cell death rate, and the chemosensitivity index.

Results

The failure rate of ATP-CRA was 1.6% (4/243). The mean coefficient of variation for triplicate ATP measurements was 6.5%. Etoposide showed the highest cell death rate (35.9%) while methotrexate showed the lowest (16.6%). The most active chemotherapeutic agent was etoposide, which most frequently ranked highest in the chemosensitivity test: 31.9% (51/160). Oxaliplatin was more active against early gastric cancers than advanced gastric cancers, whereas docetaxel was more active against advanced cancers. The lymph node negative group showed a significantly higher cell death rate than the lymph node positive group when treated with doxorubicin, epirubicin, and mitomycin.

Conclusions

ATP-CRA is a stable and clinically applicable in vitro chemosensitivity test with a low failure rate. The clinical usefulness of ATP-CRA should be evaluated by prospective studies comparing the regimen guided by ATP-CRA with an empirical regimen.

Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy

BACKGROUND

Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours.

METHODS

The chemosensitivity of a series of 31 ovarian tumours, all previously treated with platinum-based chemotherapy, was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA) and correlated with resistance gene expression measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from formalin-fixed paraffin-embedded tissue. The results were standardised against a housekeeping gene (PBGD), and assessed by multiple linear regression.

RESULTS

Predictive multiple linear regression models were derived for four single agents (cisplatin, gemcitabine, topotecan, and treosulfan), and for the combinations of cisplatin+gemcitabine and treosulfan+gemcitabine. Particularly strong correlations were obtained for cisplatin, gemcitabine, topotecan, and treosulfan+gemcitabine. No individual gene expression showed direct correlation with activity in the ATP-TCA. Genes involved in DNA repair and apoptosis were strongly represented, with some drug pumps also involved.

CONCLUSION

The chemosensitivity of ovarian cancer to drugs is related to the expression of genes involved in sensitivity and resistance mechanisms.

Individualized tumor response testing for prediction of response to Paclitaxel and Cisplatin chemotherapy in patients with advanced gastric cancer

The purpose of our study was to determine the most accurate analytic method to define in vitro chemosensitivity, using clinical response as reference standard in prospective clinical trial, and to assess accuracy of adenosine triphosphate-based chemotherapy response assay (ATP-CRA). Forty-eight patients with chemo-naïve, histologically confirmed, locally advanced or metastatic gastric cancer were enrolled for the study and were treated with combination chemotherapy of paclitaxel 175 mg/m(2) and cisplatin 75 mg/m(2) for maximum of six cycles after obtaining specimen for ATP-CRA. We performed the receiver operator characteristic curve analysis using patient responses by WHO criteria and ATP-CRA results to define the method with the highest accuracy. Median progression free survival was 4.2 months (95% confidence interval [CI]: 3.4-5.0) and median overall survival was 11.8 months (95% CI: 9.7-13.8) for all enrolled patients. Chemosensitivity index method yielded highest accuracy of 77.8% by ROC curve analysis, and the specificity, sensitivity, positive and negative predictive values were 95.7%, 46.2%, 85.7%, and 75.9%. In vitro chemosensitive group showed higher response rate (85.7% vs. 24.1%) (P=0.005) compared to chemoresistant group. ATP-CRA could predict clinical response to paclitaxel and cisplatin chemotherapy with high accuracy in advanced gastric cancer patients. Our study supports the use of ATP-CRA in further validation studies.

Complete response of anaplastic pancreatic carcinoma to paclitaxel treatment selected by chemosensitivity testing

A 58-year-old woman was admitted to our institute in June 2007 because of obstructive jaundice. A mass in the pancreatic head and multiple swollen lymph nodes surrounding the common hepatic artery were identified using computed tomography (CT). Subsequently, endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNA) was done. Histopathologic results revealed anaplastic carcinoma of the pancreas. Using specimens obtained with EUS-FNA, chemosensitivity testing with adenosine triphosphate assay was performed. Testing indicated high chemosensitivity to paclitaxel (PTX). According to this result, chemotherapy using PTX was performed, and the primary lesion and lymph node metastases disappeared completely on CT. The patient has been doing well with no recurrence for 1 year and 11 months since initial chemotherapy.

In vitro chemosensitivity in breast cancer using ATP-tumor chemosensitivity assay

Chemotherapy for breast cancer is given on the basis of empirical information from clinical trials, an approach which falls to take into account the known heterogeneity of chemosensitivity between patients. This study aimed to demonstrate the degree of heterogeneity of chemosensitivity in breast cancers. In this study, we examined the heterogeneity of chemosensitivity in breast cancer specimens (n = 50) using an ex vivo ATP-tumor chemosensitivity assay (ATP-TCA). Assay evaluability was 92% in surgical biopsies or pleural aspirates. A variety of chemosensitivity agents were tested. We found that the most active single agent tested was paclitaxel, to which 65.9% of samples were sensitive. Combinations of agents also showed more strong sensitivity cases. The Adriamycin+5-FU demonstrated a strong sensitivity in 23 of 43 (52.3%) of samples. Adriamycin+paclitaxel was more effective, with strong sensitivity in 37 of 43 cases tested (86.0%). There was a marked heterogeneity of chemosensitivity in breast cancer. Chemosensitivity testing may provide a practical method of testing new regimens before clinical trials in breast cancer patients.

Heterogeneity of adenosine triphosphate-based chemotherapy response assay in colorectal cancer--secondary publication

PURPOSE

Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is a well-documented and validated technology that can individualize chemotherapy for patients with lung, stomach, or breast cancer. This study explored the feasibility of ATP-CRA as a chemosensitivity test in patients with colorectal cancer.

MATERIALS AND METHODS

A total of 118 patients who underwent surgical resection for colorectal adenocarcinoma were analyzed for chemosensitivity to 6 anticancer drugs using ATP-CRA. We calculated the cell death rate (CDR) by measuring intracellular ATP levels of drug-exposed cells and untreated controls.

RESULTS

Interpretable results were available for 85.5% (118/138) of patients. The mean coefficient of variation for triplicate ATP measurements was 9.2%. The highest CDR was observed in irinotecan (34.0%) and the lowest CDR in etoposide (21.0%). Paclitaxel had the broadest range of CDR (0-86.7%) and 5-FU had the narrowest range of CDR (0-56.8%). The overall highest responsiveness was seen most prevalently in irinotecan (24.7%, 23/93 patients). Irinotecan had the greatest responsiveness in patients with well differentiated and moderately differentiated carcinoma.

CONCLUSION

Our study suggests that ATP-CRA could be used to identify patients with colorectal cancer who might benefit from treatment with a specific chemotherapeutic agent.

Predicting the response of advanced cervical and ovarian tumors to therapy

The management of advanced cervical and ovarian cancers remains a significant challenge as many women fail to respond to recommended therapy, resulting in disease progression and ultimately patient death. Because of tumor heterogeneity, it is rare for all cancers of a particular type to respond to a specific therapy; and, as a result, many patients receive treatment from which they derive little or no benefit, leading to increased morbidity and undue costs. A marker that could rapidly predict or forecast disease outcome would clearly be beneficial in allowing the administration of a tailored regime for each patient while reducing toxicity and cost. Traditional prognostic factors of tumor size, grade, and stage are not ideal for predicting patient outcome, whereas the use of in vitro assays to detect chemosensitivity or resistance has not yet translated into routine clinical practice. Similarly, biomarkers and tumor markers vary in their predictive ability. DNA array technology offers great promise in predicting the response to therapy based on gene expression profiles, and can allow for targeted therapies against specific molecular alterations that cause disease. Imaging techniques, particularly those with the ability to characterize biological tissues and provide functional, structural, and molecular information, have the potential to noninvasively integrate physical and metabolic information. These include F-18-fluorodeoxyglucose positron emission tomography, dynamic contrast-enhanced magnetic resonance imaging, and diffusion weighted magnetic resonance imaging, all techniques that attempt to evaluate and predict therapy response and so influence clinical outcome. This review examines different methods of predicting the response to treatment in advanced cervical and ovarian tumors.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe why prediction of response to therapy for cervical and ovarian cancers is important, describe obstacles to use of in vitro assays to predict outcomes for therapy for ovarian and cervical cancers, and explain potentially new predictive markers.

Resistance gene expression determines the in vitro chemosensitivity of non-small cell lung cancer (NSCLC)

Background

NSCLC exhibits considerable heterogeneity in its sensitivity to chemotherapy and similar heterogeneity is noted in vitro in a variety of model systems. This study has tested the hypothesis that the molecular basis of the observed in vitro chemosensitivity of NSCLC lies within the known resistance mechanisms inherent to these patients' tumors.

Methods

The chemosensitivity of a series of 49 NSCLC tumors was assessed using the ATP-based tumor chemosensitivity assay (ATP-TCA) and compared with quantitative expression of resistance genes measured by RT-PCR in a Taqman Array™ following extraction of RNA from formalin-fixed paraffin-embedded (FFPE) tissue.

Results

There was considerable heterogeneity between tumors within the ATP-TCA, and while this showed no direct correlation with individual gene expression, there was strong correlation of multi-gene signatures for many of the single agents and combinations tested. For instance, docetaxel activity showed some dependence on the expression of drug pumps, while cisplatin activity showed some dependence on DNA repair enzyme expression. Activity of both drugs was influenced more strongly still by the expression of anti- and pro-apoptotic genes by the tumor for both docetaxel and cisplatin. The doublet combinations of cisplatin with gemcitabine and cisplatin with docetaxel showed gene expression signatures incorporating resistance mechanisms for both agents.

Conclusion

Genes predicted to be involved in known mechanisms drug sensitivity and resistance correlate well with in vitro chemosensitivity and may allow the definition of predictive signatures to guide individualized chemotherapy in lung cancer.

Predictive value of individualized tumor response testing by ATP-based chemotherapy response assay in ovarian cancer

The aim of this study is to investigate the correlation between ATP-based chemotherapy response assay (ATP-CRA) results and clinical outcomes in ovarian cancer. Twenty-nine fresh tumor specimens were collected. Tumor cells were isolated and cultured for 48 hrs in medium containing anticancer drugs. The median age of patients was 56 years. The sensitivity, positive predictive value, and accuracy of ATP-CRA were respectively 94.1%, 94.1%, and 90.0%. There was a significant relationship between ATP-CRA results and clinical responses (p = 0.046). This study suggests that ATP-CRA has high sensitivity, positive predictive value, and accuracy for predicting response to chemotherapy in ovarian cancer.

A prospective randomized controlled trial of tumour chemosensitivity assay directed chemotherapy versus physician's choice in patients with recurrent platinum-resistant ovarian cancer

The primary aim of this randomized trial was to determine response rate and progression-free survival following chemotherapy in patients with platinum-resistant recurrent ovarian cancer, who had been treated according to an ATP-based tumour chemosensitivity assay in comparison with physician's choice. A total of 180 patients were randomized to assay-directed therapy (n=94) or physician's-choice chemotherapy (n=86). Median follow-up at analysis was 18 months. Response was assessable in 147 patients: 31.5% achieved a partial or complete response in the physician's-choice group compared with 40.5% in the assay-directed group (26 versus 31% by intention-to-treat analysis respectively). Intention-to-treat analysis showed a median progression-free survival of 93 days in the physician's-choice group and 104 days in the assay-directed group (hazard ratio 0.8, 95% confidence interval 0.59-1.10, not significant). No difference was seen in overall survival between the groups, although 12/39 (41%) of patients who crossed over from the physician's-choice arm obtained a response. Increased use of combination therapy was seen in the physician's-choice arm during the study as a result of the observed effects of assay-directed therapy in patients. Patients entering the physician's-choice arm of the study during the first year did significantly worse than those who entered in the subsequent years (hazard ratio 0.44, 95% confidence interval 0.2-0.9, P<0.03). This small randomized clinical trial has documented a trend towards improved response and progression-free survival for assay-directed treatment. Chemosensitivity testing might provide useful information in some patients with ovarian cancer, although a larger trial is required to confirm this. The ATP-based tumour chemosensitivity assay remains an investigational method in this condition.

Extreme drug resistance is common after prior exposure to paclitaxel

OBJECTIVE

The platinum-free interval (PFI) is an important entity in the treatment of women with epithelial ovarian cancer. The purpose of this study was to determine on clinical samples whether a taxane-free interval (TFI), as defined by in vitro extreme drug resistance assay, existed in women previously exposed to platinum and taxane chemotherapy.

METHODS

Records were examined from 2003 to 2006 to find all patients with epithelial ovarian cancer who had previous exposure to platinum and taxane therapy. Further examination was done to find all patients who underwent secondary cytoreduction and had their tumor submitted for extreme drug resistance assay.

RESULTS

Thirty-four women meeting the above criteria were found. The mean PFI was 25 months (median 18). The mean TFI was 27 months (median 20). Over 44% of the patients have been exposed to more than just a course of platinum and a course of a taxane. In patients having a PFI of >or=12 months, 38.8% had extreme drug resistance (EDR) to carboplatin and 41.9% EDR to cisplatin. Conversely, in patients having a TFI of >or=12 months, 89.7% had EDR to paclitaxel and 82.8% EDR to docetaxel.

CONCLUSIONS

While only a small percentage have EDR to carboplatin and cisplatin after a PFI of >or=12 months, almost 90% of patients with a TFI>or=12 months showed EDR to paclitaxel in vitro.

The use of an in vitro adenosine triphosphate-based chemotherapy response assay to predict chemotherapeutic response in breast cancer

The adenosine triphosphate-based chemotherapy response assay (ATP-CRA) has the advantages of standardization, evaluability, reproducibility, and accuracy, and can be performed on relatively small numbers of tumor cells. A total of 43 patients were enrolled in the present study, and chemosensitivity tests were successfully performed in 40 (93.0%) of these patients. Twenty of the 40 received neoadjuvant chemotherapy or chemotherapy for metastatic breast cancer. The chemotherapy regimens used were doxorubicin plus docetaxel (n=9, 45.0%) or doxorubicin plus paclitaxel (n=11, 55.0%). Mean cell death rate, as determined by ATP-CRA, was lower in non-responders than in responders to therapy (P=0.012). Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for ATP-CRA were 78.6%, 100%, 100%, 66.7%, and 85.0%, respectively. Diagnostic accuracy achieved by immunohistochemistry using estrogen receptor or progesterone receptor was lower than that achieved using ATP-CRA. Expression of p53, erb-B2, Ki67, Bcl-2, Bcl-xL, and annexin I was not significantly associated with response to chemotherapy. Our results show that ATP-CRA has high specificity and positive predictive value for predicting response to chemotherapy.

Adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided platinum-based 2-drug chemotherapy for unresectable nonsmall-cell lung cancer

BACKGROUND

The study investigated correlations between adenosine triphosphate / chemotherapy response assay (ATP-CRA) and clinical outcomes after ATP-CRA-guided platinum-based chemotherapy for unresectable nonsmall-cell lung cancer (NSCLC).

METHODS

The authors performed an in vitro chemosensitivity test, ATP-CRA, to evaluate the chemosensitivities of anticancer drugs such as cisplatin, carboplatin, paclitaxel, docetaxel, gemcitabine, and vinorelbine for chemonaive, unresectable NSCLC. The cell death rate was determined by measuring the intracellular ATP levels of drug-exposed cells compared with untreated controls. A sensitive drug was defined as a drug producing 30% or more reduction in ATP compared with untreated controls. Assay-guided platinum-based 2-drug chemotherapy was given to patients with pathologically confirmed NSCLC.

RESULTS

Thirty-four patients were enrolled. Thirty tumor specimens were obtained by bronchoscopic biopsies and 4 obtained surgically. The median age was 61 years and 27 patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. The response rate was 43.8%. At a median follow-up period of 16.9 months, the median progression-free and overall survivals were 3.6 and 11.2 months, respectively. Patients were dichotomized into the platinum-sensitive (S; 20 patients) and resistant (R; 14 patients) groups. The positive/negative predictive values were 61.1% and 78.6% with a predictive accuracy of 68.8%. Although without significant differences in pretreatment parameters, the S-group showed better clinical response (P=.036), longer progression-free survival (P=.060), and longer overall survival (P=.025).

CONCLUSIONS

Despite using bronchoscopic biopsied specimens, ATP-CRA and clinical outcomes correlated well after assay-guided platinum-based 2-drug chemotherapy for unresectable NSCLC. There was a favorable response and survival in the platinum-sensitive vs resistant groups.

Genetic diagnosis for chemosensitivity with drug-resistance genes in epithelial ovarian cancer

We conducted the present study to investigate whether and how chemosensitivity can be determined by means of genetic diagnosis using drug-resistance genes in patients with epithelial ovarian cancer. A total of 75 patients who had epithelial ovarian cancer with measurable lesions were entered into this study. Thirty-three patients received first-line chemotherapy, consisting of paclitaxel and carboplatin (TJ). Forty-two patients received second-line chemotherapy, 22 received EP therapy consisting of etoposide and cisplatin (CDDP), and 20 received irinotecan (CPT-11) and CDDP (CPT-11/CDDP) therapy. Tumor samples were obtained before chemotherapy. MessengerRNA expressions of the multidrug-resistance (MDR)-1 gene, MDR-associated protein-1 (MRP-1), topoisomerase (topo) I, and topo IIalpha were measured by real-time reverse transcription-polymerase chain reaction. The cutoff values of each gene were determined by the receiver operating characteristic curve. MDR-1 expression was significantly higher in patients who did not respond to TJ therapy. The expression of topo IIalpha was significantly higher in patients who did respond to EP therapy. The expression of topo I was significantly higher in patients who did respond to CPT-11/CDDP. MRP-1 expression did not differ between responders and nonresponders in all regimens. The cutoff value was 80 for MDR-1, 90 for topo IIalpha, and 200 for topo I. Next, to evaluate genetic diagnosis, 31 patients were newly added. The accuracy of this genetic diagnosis for chemosensitivity was 85.7% for TJ, 77.8% for EP, and 100.0% for CPT-11/CDDP therapy. The present study suggests that genetic diagnosis may be useful to determine chemosensitivity in patients with epithelial ovarian cancer.