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.

B64 Introduction: NSCLC exhibits considerable heterogeneity in its sensitivity to chemotherapy. This study has tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients9 tumors.Methods: The chemosensitivity of a series of 29 tumors was assessed using the ATP-based tumor chemosensitivity assay (ATP-TCA)against cisplatin, and docetaxel, alone and in combination. The results were correlated with quantitative expression of resistance genes measured by RT-PCR in a Taqman Low Density Array (Applied Biosystems) following extraction of mRNA from formalin-fixed paraffin-processed tissue using the AB 6100 extraction system. The results were standardised against the least variable housekeeping gene (PBGD) of those tested. The relationship between chemosensitivity and gene expression was assessed by multiple linear regression analysis.Results: No individual gene expression showed direct correlation with activity in the ATP-TCA. However, docetaxel activity showed some dependence on the expression of Beta-tubulin III, BCRP, MDR1, MRP2 and GSTpi, while cisplatin activity showed some dependence on DNA repair enzyme expression (e.g. ERCC1, MLH1, MSH6). Activity of both drugs was influenced more strongly still by the expression of anti- and pro-apoptotic genes by the tumor for both docetaxel (p

E. coli O157:H7 is a pathogenic microorganism that has been implicated in numerous cases of foodborne illnesses. A variety of rapid methods exist that show promise for the presumptive detection of this pathogen without the immediate need for incubating test samples for hours to days in microbial enrichment and culture media. In recent years, highly sensitive chemiluminescence has become a more affordable and portable detection method. Chemiluminescent detection has been coupled with the selectivity of antibodies, magnetic microparticle separation/isolation, and enzymatic signal amplification in order to develop a rapid method, termed enzyme-linked immunomagnetic chemiluminescence (ELIMCL). This work presents the application of ELIMCL to the detection of E. coli O157:H7 in pristine buffered saline with a detection limit of 7.6 x 10(3) for live cells in approx. 75 min assay time. The blocking agent casein and the surfactant Tween 20 were used to lower background luminescence and thus maximize signal-to-noise ratios. After 5.5 h of enrichment culture, ELIMCL was demonstrated to detect E. coli O157:H7 inoculated in ground beef at 10 CFU/g in a total assay time of about 7 h.

Immunoassays have evolved for a broad range of applications since the pioneering work, of Yalow and Berson who developed the first competitive radioimmunoassay (RIA) for human insulin in 1959. Immunoassay detection of specific antigens and host-produced antibodies directed against such antigens constitutes one of the most widely used and successful methods for diagnosing infectious diseases (IDs). The number and variety of new assay systems that are continually being developed reflect the increasing demand for immunoassays possessing greater sensitivity, speed, and ease of use. This trend has been driven, in part, by the need,for improved immunodiagnostic systems to perform rapid testing and counter emerging IDs and biothreat (BT) agents. Another factor driving this trend is the need to integrate immunoassays with more sensitive nucleic acid-based methods for a comprehensive approach. Here we examine the development of immunoassays, some of the key formats used for the detection and identification of BT/ID agents, and the application of these technologies under different scenarios.

The application of in vitro and in vivo ATP bioluminescence systems as an integrated approach for preclinical research and development of new chemotherapeutic drugs is described. This approach includes both (a) the in vitro tumor response assay (TRA) system that utilizes new technologies for cell culture and ATP measurement of clinical specimens and (b) the use of human tumor cell lines transfected with Photinus pyralis luciferase (luc) gene for both in vitro and in vivo studies. Dried reagent microplates for TRA culture and counting procedures are described for a two-stage TRA method, which can be used to evaluate drug sensitivity and resistance of cells from clinical specimens after initial drug exposure in vitro. The use of dried reagent counting plates for screening and testing of agents against tumor cell lines is described, as well as an alternative method for screening and testing chemotherapeutic drugs in vitro with luc-transfected human tumor cell lines. The potential application of luc-transfected reporter cell lines for in vivo studies of drug activity with photon imaging for analysis is discussed.

Trophoblast injury may be one of the possible causes of fetal distress associated with chemotherapy administered during pregnancy. The purpose of this study was to investigate the ex vivo chemosensitivity of normal trophoblasts (NTB) against commonly used antineoplastic agents. Using the newly developed ex vivo ATP-based trophoblast assay (ATP-TBA), 31 NTB freshly sampled from human placentas (gestational week 7–42) were tested against dactinomycin (Act-D), 5-fluorouracil (5-FU), 4-OOH-cyclophosphamide (4-HC), vincristine (VCR) and methotrexate (MTX) alone or in combination with calcium folate (LV). All agents were studied at concentrations relevant to clinical dosages normally used for chemotherapy of solid neoplasms. Of 31 samples studied with the ATP-TBA, 20 (65%) were evaluable. VCR, Act-D and 4-HC were the most active drugs with 55, 45 and 45% of samples responding ex vivo. Antimetabolites were less active, producing ex vivo response rates of 25 (MTX) and 20% (5-FU), respectively. MTX activity was largely neutralized by adding LV. The chemosensitivity of NTB showed considerable inter-individual variations and did not decrease with increasing gestational age. We therefore conclude that NTB of any gestational age exhibit considerable ex vivo sensitivity against common anticancer agents which is comparable to that observed for various solid tumors. The ATP-TBA may be helpful in planning future trials with both single agents and drug combinations in order to standardize and optimize chemotherapy during pregnancy.

s of the 1st Symposium of the International Society for Chemosensitivity Testing in Oncology

A compact new luminometer (FB12) has been developed based on a 370-630 nm photon counter and measuring chamber that can accommodate a range of sample formats. The FB12 permits measurements as low as 1000 molecules of luciferase in reporter gene assays. Its sensitivity for ATP is limited by reagent background. If ATP assay reagents had no chemical background, 2 fg of ATP could be detected using 3 SD of instrument background as the detection limit. The FB12 has a dynamic range of six decades and operates under its own microprocessor programme or protocol-based PC software that is integrated with Microsoft(R) Excel(R). An injector port above the sample measuring position allows connection of external reagent injectors. Applications are performed using protocols provided with the FB12 or user defined protocols. Examples are presented that illustrate use of the instrument for research and industrial applications.

Advanced melanoma has a poor prognosis and chemotherapy provides little benefit for most patients. This may be related to heterogeneity of chemosensitivity as well as frequent constitutive resistance to individual cytotoxic drugs. We have therefore examined the heterogeneity of chemosensitivity in metastatic cutaneous melanoma specimens using an ex vivo ATP-based chemosensitivity assay (ATP-TCA). Melanoma deposits (n=55) in skin or lymph node were tested using the ATP-TCA, performed in three separate laboratories. Analysis of the data collected (based on an arbitrary sensitivity index < 300) shows considerable heterogeneity of chemosensitivity. The most active single cytotoxic agents in the assay were identified as cisplatin, treosulfan, paclitaxel, vinblastine, gemcitabine and mitoxantrone. There was also a limited direct inhibition of melanoma cell growth by interferon-alpha2b, although this agent is known to have a number of indirect biological antitumor effects. Exposure of tumor cells to combinations of drugs at the concentrations tested as single agents showed the most active combinations to be treosulfan+gemcitabine, cisplatin+paclitaxel and vinblastine+paclitaxel. There was considerable heterogeneity of chemosensitivity: some tumors responded well to one agent or combination, while others showed no response to this and instead responded to one of the alternatives tested. Occasional highly resistant tumors showed no response to any of the single agents or combinations tested. The degree of heterogeneity observed suggests that the ATP-TCA could be used to select patients who might benefit from specific chemotherapeutic agents alone or in combination. This provides the rationale for future randomized controlled trials of ATP-TCA-directed chemotherapy versus physician's choice to determine whether assay-directed chemotherapy can improve patient response and survival.

Chemotherapy for recurrent ovarian carcinoma (ROC) produces response rates of 10-80% depending on the prevalence of platinum resistance. Most patients relapse within 1 year and median progression-free survival (PFS) is generally no more than 6 months. Previous pretherapeutic chemosensitivity assays mostly failed to improve the outcome of patients with ROC. Newly developed ATP assays show promising retrospective correlation with clinical outcome. We report here the first results of ATP assay-directed chemotherapy in patients with ROC. Therapy was selected by the ATP tumor chemosensitivity assay (ATP-TCA) in a prospective open-label pilot trial for ROC. Objective response rate (ORR), PFS and overall survival (OAS) of the first 25 evaluable patients were retrospectively compared with those of 30 others having similar characteristics who were treated empirically within the same period. The actuarial median observation times were 80 weeks for the ATP-TCA group and 83.5 weeks for the control group, respectively. In the control group, a 37% ORR [two complete responses (CR) and nine partial responses (PR)] was followed by a median PFS of 20 weeks and a median OAS of 69 weeks, mainly related to the use of single-agent chemotherapy. The ORR in the ATP-TCA group was 64% (eight CR and eight PR) (p=0.04) with the majority of responses (11 of 16) achieved with novel combinations. The median PFS in this group was 50 weeks (p=0.003) and the median OAS was 97 weeks (p=0.145). Survival of responding patients was similar in both groups. Chemotherapy guided by the ATP-TCA produced a greater benefit with regard to both ORR and PFS in platinum-refractory patients. ATP-TCA-directed chemotherapy for ROC compares favorably with chemotherapy chosen by a clinician and often leads to the choice of novel drug combinations. These promising results now warrant confirmation by prospective randomized trials.

This report describes preclinical and early clinical investigations of the mitoxantrone/paclitaxel combination (NT) for patients with platinum-refractory ovarian cancer. The preclinical activity of NT was studied ex vivo, evaluating native tumor specimens with the ATP tumor chemosensitivity assay. Of 24 tumors tested, 20 (83%) were sensitive to NT, whereas 7 (29%) responded to mitoxantrone and 8 (33%) responded to paclitaxel. In the majority of tumors assayed (19 of 24), potentiating or major independent effects between both agents were found. Subsequently, a clinical pilot trial of NT was initiated for patients with platinum-refractory ovarian cancer. Patients had failed one to four (median, two) prior chemotherapy regimens. In 11 cases, NT was administered every three weeks with 8 mg/m2 mito-xantrone and 180 mg/m2 paclitaxel (NT-I). Seven patients were treated biweekly with 6 mg/m2 mitoxantrone and weekly with 100 mg/m2 paclitaxel (NT-II). During 92 NT courses, myelosuppression with leucopenia, anemia, and thrombocytopenia was the limiting toxicity, occurring more frequently with NT-II. No patient required hospitalization due to any life-threatening complication. Five complete and nine partial remissions were observed with both NT-I and NT-II, accounting for an overall 78% response rate, with a median progression-free survival of 40 weeks. One patient showed early progression during therapy. Currently, three patients (NT-I, two; NT-II, one) have died due to progressive relapsed ovarian cancer, so that the median overall survival is not reached after a median follow-up of 40.5+ weeks. Both schedules were found to be equal in terms of response rate and overall survival. NT is highly active and practical for salvage treatment of ovarian cancer. NT-II may be preferred due to both clinical activity and patients' acceptance. However, NT-I seems to be a less myelotoxic alternative. Both schedules warrant further clinical investigation.

Drug discovery and toxicological safety testing share a need for dependable in vitro cellular toxicity tests. Ideally such tests should be objective, quantitative, reproducible and able to lend themselves to automation. A number of assays fulfil these criteria well, but recently it has become clear that the molecular phenotype of the cell tested and the complex interplay between different cell types can radically alter the response to individual agents. The differences observed between primary cell cultures and cell lines make it preferable to use primary cultures for assessment of toxicity, yet the problems of using primary cell cultures are considerable as the number of cells available for testing is often small. Recently, we have developed a short-term cell culture assay based on the detection of ATP by the luciferin-luciferase reaction. Four drugs/agents can be tested in triplicate at seven dilutions in one 96-well microplate with 1000 cells/well in the case of cell lines, or 10,000 cells/well for primary tumour tissue. The small number of cells required is a major advantage of this method. Initially developed as a tumour chemosensitivity assay, the assay has shown considerable promise as a general in vitro toxicity assay allowing both cell lines and primary tissue cultures to be tested. Heterogeneity of sensitivity is present in benign tissue biopsies as well as tumours. Molecular alterations within the cell and the interplay of different cell types have been addressed in a number of different model systems using the assay, suggesting that this technology may have more general application.

Chemotherapy for breast cancer is given on the basis of empirical information from clinical trials, an approach which fails to take into account the known heterogeneity of chemosensitivity between patients. Previous attempts to determine chemosensitivity ex vivo have been disappointing, but in this study results from a newly developed tumor chemosensitivity assay (TCA) have been correlated prospectively with patient response. In this study, we have used heterogeneity data for standard regimens obtained from 116 breast TCAs to set sensitivity/resistance thresholds which were then used to interpret the results from those with known clinical responses. Assay evaluability was 97% in surgical biopsies. Clinical follow-up of stage III/ IV assessable disease was obtained from 27 breast tumors which were successfully tested for chemosensitivity, including 13 needle biopsies. The ATP-TCA assay predicted response correctly in 22 out of 29 (76%) tumors with clinically evaluable disease, suggesting that it is capable of predicting outcome in individual patients. Assays were performed in seven patients before and after chemotherapy using residual or recurrent tumor tissue. Four cases with initial sensitivity showed a decrease in sensitivity within 6 months of starting chemotherapy, while two others without clinical resistance were still sensitive by TCA. All nine courses of therapy given on the basis of TCA sensitivity resulted in partial or complete responses. Controlled trials of TCA-directed treatment against standardized empirical therapy should be conducted before this technology is widely adopted to assess its impact on rates of response, survival and the cost of treatment.

Apart from clinical trials, mitoxantrone (MX) is rarely used in breast cancer (BC) due to the anticipated anthracycline cross-resistance. We have examined this drug versus doxorubicin (DOX) using data obtained fromin vitro microplate ATP tumor chemosensitivity assays (ATP-TCA) of BC cells which were derived from 55 chemotherapy-naive patients at time of primary surgery. Both drugs were tested at 6 different concentrations ranging from 6.25% to 200% peak plasma concentrationin vivo (PPC). Differences between DOX and MX observed for mean IC50, IC90, and a sensitivity index (SI) were not statistically significant.In vitro response rates were 44% for DOX and 52% for MX. 34 of 52 eligible assays (65%) showed comparable activity of both drugs whereas a lack of cross-resistance was observed in the remaining 18 (35%) tumors as indicated by differences for SI. Cumulative concentration-response plots of tumors respondingin vitro with a ≥ 50 percent or ≥ 90 percent tumor cell inhibition showed a strong dose-dependence for both DOX and MX at concentrations which normally can be achieved within clinical tumors (i.e. 6.25%-50% PPC). At higher concentrations, however, cytotoxicity of DOX and MX could not be improved by furtherin vitro dose escalation. Moreover, a substantial proportion of BC specimens (DOX: 48.1%; MX: 40.4%) did not experience a ≥ 90 tumor cell inhibition at 200% PPC. In conclusion,in vitro results obtained by ATP-TCA indicate that there is no cross-resistance between MX and DOX in a substantial proportion of BC patients. This may be clinically useful and suggests that combinations including MX should be tested in patients clinically resistant to DOX containing regimens. Since both drugs produced sigmoidal concentration-response curves, dose escalation beyond a certain point may not produce increased sensitivity.

Utilizing a microplate ATP bioluminescence assay, two human breast carcinoma cell lines, MCF-7 and MDA-MB-231, were tested against doxorubicin (DOX), cisplatin (DDP), and paclitaxel (Tx) alone and in combination with ascorbic acid (Vit C). In both cell lines, Vit C exhibited cytotoxic activity at high concentrations (i.e. 102–103 μM). Both cell lines also were resistant to DOX. MCF-7 was found to be DDP-resiseant, MDA-MB-231 was moderately sensitive to DDP. Both cell lines were strongly sensitive to Tx. Vit C both at non-cytotoxic (1 μM) and moderately cytotoxic concentrations (102μM) improved the cytotoxicity of DOX, DDP, and Tx significantly. Combination effects between Vit C and DDP or Tx were partly synergistic and partly additive or subadditive whereas a consistent synergism was found between Vit C and DOX. The mechanisms by which Vit C potentiates the cytostatics studied are yet unclear and should be evaluated further.