Role of laboratory chemosensitivity testing in the selection of cancer chemotherapy for individual patients

Characterization of organoid cultured human breast cancer

Organoid cultures are increasingly used to model human cancers experimentally with a view to tailoring personalized medicine and predicting drug responses. Breast cancer is no exception, but in particular, primary breast cancer poses some inherent difficulties due to the frequent presence of residual non-malignant cells in the biopsies. We originally developed an assay for the distinction between malignant and non-malignant structures in primary breast cancer organoid cultures (Petersen et al., Proc Natl Acad Sci (USA) 89(19):9064–8, 1992). Here, we apply this assay to assess the frequency of normal-like organoids in primary breast carcinoma cultures and the cellular composition as a consequence of passaging. We find that in consecutively collected samples of primary human breast cancers, residual non-malignant tissues were observed histologically in five out of ten biopsies. Based on relevant morphogenesis and correct polarization as recorded by expression in luminal epithelial cells of mucin 1 (Muc1), occludin, and keratin 19 (K19) and expression in basal cells of integrin β4, p63, and K14, non-malignant organoids were present in all primary human breast cancer-derived cultures. Furthermore, passaging in a contemporary culture medium was in favor of the selective expansion of basal-like cells. We conclude that organoid cultures of human breast cancers are most representative of the tissue origin in primary culture.

Potential CD34 signaling through phosphorylated-BAD in chemotherapy-resistant acute myeloid leukemia

Acute myeloid leukemia (AML) constitutively express growth factors and cytokines for survival. Chemotherapy alters these signals to induce cell death. However, drug resistance in AML remains a major hindrance to successful treatment and early warning is unavailable. Modulation of signaling pathways during chemotherapy may provide a window to detect response and predict treatment outcome. Blood samples collected from AML patients before and at day-3 of induction therapy were compared for changes in expression of CD117, CD34, pro-inflammatory cytokines and mediators of Akt and MAPK pathways, using multi-color flow cytometry. Nine patients were diagnosed as drug-resistant and seven sensitive to chemotherapy. Twelve were paired. Average percentages of CD34 (66.8 ± 11.7% vs. 26.2 ± 5.8%, p = 0.033) and pBAD (66.9 ± 8.2% vs. 28.9 ± 8.2%, p = 0.016) were significantly increased in chemo-resistant (N = 9) compared to chemo-sensitive (N = 5) samples. Percentages of CD34 were strongly correlated with pBAD (R = 0.785; p = 0.001; N = 14) and pFKHR (R = 0.755; p = 0.002; N = 14) at day-3 induction. Chemo-sensitive cases expressed significantly higher percentages of IL-18Rα (71.9 ± 9.6% vs. 29.8 ± 5.8%, p = 0.016). Though not significantly different in the outcome, IL-1β was strongly associated with activated Akt-S473, IL-6 with phosphorylated JNK and FKHR while TNF-α appeared to trigger Bim, in treated samples. These preliminary results suggested AML cells resistant to chemotherapy increased expression of CD34 and may signal through pBAD while cells sensitive to chemotherapy-induced IL18Rα expression. These were observed early during induction therapy. Identifying CD34 is interesting as it is a convenient marker to monitor drug-resistance in AML patients. Inhibition of CD34 and pBAD signaling may be important in treating drug-resistant AML.

Evolution of Chemosensitivity and Resistance Assays as Predictors of Clinical Outcomes in Epithelial Ovarian Cancer Patients

Epithelial ovarian cancer (EOC) is responsible for more cancer-related deaths than any other malignancy of the female reproductive system. The standard of care for advanced EOC involves a combination of cytoreductive surgery and platinum-based chemotherapy. Although a majority of patients respond to a platinum-containing regimen, many fail to respond to first-line treatment (platinum-refractory disease) or experience disease progression within 6 months of completing treatment (platinum-resistant disease). Even in patients who initially respond to platinum-based therapy, secondary development of platinum resistance is common. Many chemotherapeutic regimens with comparable efficacy and toxicities are available, leaving the determination of optimal therapy to the physician's discretion. There have been many efforts over the years to develop accurate predictors of outcomes in patients treated with chemotherapy to help inform treatment decisions. Predictive treatment markers are particularly relevant in a disease such as EOC, where a large number of similarly efficacious chemotherapy regimens are available. Chemosensitivity and resistance assays (CSRAs) are attractive approaches to interrogate the efficacy and complex biology of EOC. Some early predictive cellular tests, such as the early clonogenic assays, were limited by technical and logistical issues. Over time, changes in these assays have improved their prognostic and predictive value, but there is still a lack of widespread adoption due to methodological difficulties or limited clinical validation. Herein, we provide an overview of the evolution of CSRAs used to predict outcomes in patients treated with chemotherapy that have been evaluated for use in EOC, with a focus on the latest generation chemoresponse assay.

Overview of a chemoresponse assay in ovarian cancer

The objective of this review is to summarize recent scientific and medical literature regarding chemoresponse assays or chemotherapy sensitivity and resistance assays (CSRAs), specifically as applied to epithelial ovarian cancer. A total of sixty-seven articles, identified through PubMed using the key words “in vitro chemoresponse assay,” “chemo sensitivity resistance assay,” “ATP,” “HDRA,” “EDR,” “MiCK,” and “ChemoFx,” were reviewed. Recent publications on marker validation, including relevant clinical trial designs, were also included. Recent CSRA research and clinical studies are outlined in this review. Published findings demonstrate benefits regarding patient outcome with respect to recent CSRAs. Specifically, analytical and clinical validations, as well as clinical utility and economic benefit, of the most common clinically used CSRA in the United States support its use to aid in making effective, individualized clinical treatment selections for patients with ovarian cancer.

Viability analysis and apoptosis induction of breast cancer cells in a microfluidic device: effect of cytostatic drugs

Breast cancer is the leading cause of cancer deaths among non-smoking women worldwide. At the moment the treatment regime is such that patients receive different chemotherapeutic and/or hormonal treatments dependent on the hormone receptor status, the menopausal status and age. However, in vitro sensitivity testing of tumor biopsies could rationalize and improve the choice of chemo- and hormone therapy. Lab-on-a-Chip devices, using microfluidic techniques, make detailed cellular analysis possible using fewer cells, enabling working with a patients' own cells and performing chemo- and hormone sensitivity testing in an ex vivo setting. This article describes the development of two microfluidic devices made in poly(dimethylsiloxane) (PDMS) to validate the cell culture properties and analyze the chemosensitivity of MCF-7 cells (estrogen receptor positive human breast cancer cells) in response to the drug staurosporine (SSP). In both cases, cell viability was assessed using the life-stain Calcein-AM (CAAM) and the death dye propidium iodide (PI). MCF-7 cells could be statically cultured for up to 7 days in the microfluidic chip. A 30 min flow with SSP and a subsequent 24 h static incubation in the incubator induced apoptosis in MCF-7 cells, as shown by a disappearance of the aggregate-like morphology, a decrease in CAAM staining and an increase in PI staining. This work provides valuable leads to develop a microfluidic chip to test the chemosensitivity of tumor cells in response to therapeutics and in this way improve cancer treatment towards personalized medicine.

Towards a molecular approach to gastric cancer management

Gastric cancer is a leading cause of cancer death worldwide. Most patients with gastric cancer present with locally advanced and incurable disease, and overall survival is poor. Considerable research efforts towards the epidemiology and pathogenesis of gastric cancer have not been translated into treatment success. We discuss current concepts of the pathogenesis of gastric cancer and how recent research advances, in particular global gene expression strategies, may improve this understanding, and suggest a framework wherein these approaches may be used.

Proliferation, esterase activity, and propidium iodide exclusion in urologic tumor cells after in vitro exposure to chemotherapeutic agents

After exposing urological tumor cells to anticancer agents in vitro, cellular esterase activity and the ability to exclude propidium iodide (PI) were examined as dual indicators of functionality or "viability." High esterase activity/PI exclusion was observed in assays in which anticancer agents failed to inhibit cellular proliferation, while low esterase activity/PI exclusion was often observed when proliferation had been significantly inhibited. In a number of instances, exposure to anticancer agents did produce significant inhibition of proliferation without lowering viability. In this setting, the recovery of proliferative capacity could be demonstrated with several transitional cell carcinoma cell lines, and this recovery was always associated with high esterase activity/PI exclusion. When the proliferation of primary urological tumor preparations was inhibited by drug exposure, estimates of elevated viability were obtained in 27 per cent of the determinations. Thus, viability estimates may be an indicator of the potential for tumor-cell recovery from exposure to anticancer agents. Moreover, the potential for recovery may explain differences between the results of chemosensitivity testing and actual clinical events by reconciling clinical failures with elevated viabilities indicative of this potential.

Esterase activity, exclusion of propidium iodide, and proliferation in tumor cells exposed to anticancer agents: phenomena relevant to chemosensitivity determinations

Cellular esterase activity and the ability to exclude propidium iodide were examined after exposing tumor cells to anticancer agents. In general, esterase activity and the ability to exclude propidium iodide continued when cells proliferated and disappeared when proliferation was inhibited. However, with a number of preparations, drug exposure inhibited proliferation while esterase activity and propidium iodide exclusion persisted. These indications of persisting cell function or viability after drug exposure may be relevant to a potential for tumor cell recovery. When the viability of established cell lines progressively declined on days 4 and 7 following drug exposure, recovery did not occur. When proliferative recoveries occurred, viabilities remained elevated. Estimates of in vitro sensitivity by proliferation-related criteria were contrasted by persistent high viability estimates in 22% of the determinations performed with primary tumor cell preparations. The potential for recovery may explain the disappointing ability of proliferative chemosensitivity assays to predict clinical sensitivity.

Applications of a human tumour clonogenic cell culture system in gynaecological oncology: review and personal experience

Current and future clinical applications of the Human Tumour Clonogenic Cell Culture (HTC3) system are presented. Advanced gynaecological cancers, especially ovarian, endometrial and cervical carcinomas, require extensive systemic chemotherapy. The HTC3 system seems to be an adequate instrument for individualized chemosensitivity testing in order to choose proper cytostatic treatments; that is, maximum tumour cell kill with minimal side-effects. Furthermore, this system helps in assessing the response after treatment by detection of remaining clonogenic, and thus viable, tumour cells. Other clinical applications of the system include grading of the tumour and recognition of the histologic type. Thus the HTC3 provides a potential tool in diagnosis, treatment and follow-up of gynaecologic malignancies.

The proliferation of human tumor cell lines in the presence of different agars, agaroses, and methyl cellulose

Human tumor cell lines, derived from cancers of the colon, ovary, and cervix, were grown in liquid tissue culture media and media made semisolid with agar (Bacto + deoxycholate lactose agar), agarose [LE, ME, Sea Plaque and Sea Prep (15/45)], and methyl cellulose. The effects of each agent on overall cell proliferation and rate of overall cell proliferation were examined. The agents, used to make media semisolid, were observed to inhibit or, in some cases, enhance cell growth in a fashion that was characteristic of individual cell lines. These phenomena may be of consequence to the optimization of nutrient media for primary tumor cell preparations.

The effect of different agars, agaroses and methyl cellulose on the in vitro proliferation of a human urinary transitional cell carcinoma cell line

The effects of different agars (Bacto-agar and deoxycholate lactose agar), agaroses (LE, ME, Sea Plaque and Sea Prep 15/45) and methyl cellulose on the growth of a human tumor cell line, derived from a transitional cell carcinoma of the urinary bladder, were examined. The overall growth in the presence of agars and agarose was generally less than in liquid medium alone. In contrast, growth in the presence of methyl cellulose was significantly enhanced. Thus, methyl cellulose may be a useful agent for optimizing the proliferation of primary tissue cultures prepared from human transitional cell carcinomas.

Growth pattern of tumor xenografts in Wistar rats after treatment with cyclophosphamide, total lymphoid irradiation and/or cyclosporin A

Wistar rats treated with cyclophosphamide, total lymphoid irradiation (TLI), and/or cyclosporin A (CSA) develop a state of immune suppression permitting the growth of tumor xenografts. Experiments were carried out on this newly developed model to investigate the growth patterns of a mouse osteosarcoma and a human colon adenocarcinoma. The combination of cyclophosphamide and CSA permitted a limited period of growth of the mouse osteosarcoma with a tumor take rate of 66%. No takes were observed with the human adenocarcinoma. The combination of cyclophosphamide and TLI resulted in a period of immunosuppression followed by recovery of the immune status. During the period of immunosuppression, tumor xenografts showed a 100% take rate. The most efficient immunosuppression was achieved by a combination of cyclophosphamide, TLI and CSA administered on alternate days. Wistar rats subjected to this treatment showed prolonged tolerance to mouse osteosarcoma and human adenocarcinoma xenografts. There was no alteration in the tumor doubling time or histological morphology of the xenografts in the adapted host as compared with those in the donor tumors. The tumor growth curve showed a pattern of initial growth, a period of stagnation, followed by a steady but slower growth phase. The significance of the results and the advantages of the rat model described in this paper for human tumor xenotransplantation are discussed.

Limitations of the clonal agar assay for the assessment of primary human ovarian tumour biopsies

114 biopsy specimens from 70 patients with ovarian carcinoma at all stages of disease were submitted for assessment of clonogenic capacity in agar. A highly significant correlation was found between agar clonogenicity and patient survival after biopsy. However, problems related to inherent tumour heterogeneity, quality of sample and tissue disaggregation indicate that this technique may have limited applicability in the routine assessment of patients. Only 41 biopsy specimens (36%) from 31 patients (44.3%) complied with the prerequisite criteria for agar clonogenic assessment, namely: (a) the confirmed presence of malignant cells in the biopsy, (b) the ability to prepare a single-cell suspension, and (c) adequate viable cell numbers for assay. Furthermore, although the dominant patterns of agar clonogenic growth could be identified and correlated with stage of disease, the heterogeneity in both initial clonogenic capacity and "self-renewal" capacity assessed by the ability of primary clones to propagate in liquid culture and reclone in agar was too inconsistent for the assay to be used as a prognostic index for the individual patient.