Prediction of chemotherapeutic effect on postoperative recurrence by in vitro anticancer drug sensitivity testing in non-small cell lung cancer patients

Drug Sensitivity Testing for Cancer Therapy, Technique Analysis and Trends

The techniques and qualities of drug sensitivity testing (DST) for anticancer treatment have grown rapidly in the past two decades worldwide. Much of DST progress came from advanced systems of technical versatility (faster, highly-throughput, highly-sensitive, and smaller in tumor quantity). As the earliest drug selective system, biomedical knowledge and technical advances for DST are mutually supported. More importantly, many pharmacological controversies are resolved by these technical advances. With this technical stride, the clinical landscape of DST entered into a new phase (>500 samples per testing and extremely low quantity of tumor cells). As a forerunner of the drug selection system, DST awaits a new version that can adapt to complicated therapeutic situations and diverse tumor categories in the clinic. By upholding this goal of pathogenic and therapeutic diversity, DST could eventually cure more cancer patients by establishing high-quality drug selection systems. To smoothen DST development, there is a need to increase the understanding of cancer biology, pathology and pharmacology (cancer heterogeneity, plasticity, metastasis and drug resistance) with well-informative parameters before chemotherapy. In this article, medicinal and technical insights into DST are especially highlighted.

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.

Yes associated protein 1 promotes resistance to 5-fluorouracil in gastric cancer by regulating GLUT3-dependent glycometabolism reprogramming of tumor-associated macrophages

The antimetabolite 5-fluorouracil (5-FU) is a widely used chemotherapy regimen for the treatment of gastric cancer (GC). However, resistance to 5-FU remains a major drawback in the clinical use. The treatments of anti-tumor chemo-agents recruit tumor associated macrophages (TAMs) which are highly implicated in the chemoresistance development, but the underlying molecular mechanism is unclear. Here, we demonstrate that YAP1 is overexpressed in resistant GC tissues compared to sensitive GC tissues. Further, IL-3 secreted by YAP1-overexpressed GC could skew macrophage polarization to M2-like phenotype and inducing GLUT3-depended glycolysis program. Meanwhile, polarized M2 macrophages enhance 5-FU resistance in tumor cells by secreting CCL8 and activating phosphorylation of JAK1/STAT3 signaling pathway.

Collagen gel droplet-embedded culture drug sensitivity test (CD-DST) predicts the effect of adjuvant chemotherapy on pancreatic cancer

PURPOSE

We evaluated the clinical effectiveness of collagen gel droplet-embedded culture drug sensitivity tests (CD-DSTs) in predicting the efficacy of adjuvant chemo-therapeutic treatments for pancreatic cancer (PC).

METHODS

The clinicopathological characteristics and prognoses of 22 PC patients who underwent CD-DST after pancreatectomy at Tohoku University between 2012 and 2016 were analyzed retrospectively. Eligibility criteria were resectable or borderline resectable PC, successful evaluation for 5-fluorouracil sensitivity by CD-DST, treatment with S-1 adjuvant chemotherapy, and no preoperative chemotherapy.

RESULTS

The rate of successful evaluation by CD-DST was 52.3% in PC. The optimal T/C ratio, defined as the ratio of the number of cancer cells in the treatment group (T) to that in the control group (C), for 5-fluorouracil was 85% using receiver operating characteristic curve analysis. The sensitive group (T/C ratio < 85%; n = 11) had a better recurrence-free survival rate than the resistant group (T/C ratio ≥ 85%; n = 11; P = 0.029). A Cox proportional hazards regression model demonstrated that sensitivity to 5-fluorouracil was an independent predictor of recurrence on multivariate analysis (hazard ratio 3.28; 95.0% CI 1.20-9.84; P = 0.020).

CONCLUSIONS

CD-DSTs helped to predict PC recurrence after S-1 adjuvant chemotherapy.

A novel chemotherapeutic sensitivity-testing system based on collagen gel droplet embedded 3D-culture methods for hepatocellular carcinoma

Background

Patients suffering from advanced stage hepatocellular carcinoma (HCC) often exhibit a poor prognosis or dismal clinical outcomes due to ineffective chemotherapy or a multi-drug resistance (MDR) process. Thus, it is urgent to develop a new chemotherapeutic sensitivity testing system for HCC treatment. The presence study investigated the potential application of a novel chemotherapeutic sensitivity-testing system based on a collagen gel droplet embedded 3D–culture system (CD-DST).

Methods

Primary cells were separating from surgical resection specimens and then tested by CD-DST. To identify whether HCC cell lines or cells separating from clinical specimens contain MDR features, the cells were treated with an IC₅₀ (half maximal inhibitory concentration) or IC_max (maximal inhibitory concentration) concentration of antitumor agents, e.g., 5-furuolouracil (5-FU), paclitaxel (PAC), cisplatin (CDDP), epirubicin (EPI), or oxaliplatin (L-OHP), and the inhibitory rates (IRs) were calculated.

Results

HepG2 cells were sensitive to 5-FU, PAC, CDDP, EPI, or L-OHP; the IC₅₀ value is 0.83 ± 0.45 μg/ml, 0.03 ± 0.02 μg/ml, 1.15 ± 0.75 μg/ml, 0.09 ± 0.03 μg/ml, or 1.76 ± 0.44 μg/ml, respectively. Only eight (8/26), nine (9/26), or five (5/26) patients were sensitive to the IC_max concentration of CDDP, EPI, or L-OHP; whereas only three (3/26), four (4/26), or two (2/26) patients were sensitive to the IC₅₀ concentration of CDDP, EPI, or L-OHP. No patients were sensitive to 5-FU or PAC.

Conclusions

The in vitro drug sensitivity exanimation revealed the MDR features of HCC and examined the sensitivity of HCC cells from clinical specimens to anti-tumor agents. CD-DST may be a useful method to predict the potential clinical benefits of anticancer agents for HCC patients.

Collagen gel droplet-embedded culture drug sensitivity test for adjuvant chemotherapy after complete resection of non-small-cell lung cancer

PURPOSE

We conducted a prospective clinical study to individualize adjuvant chemotherapy after complete resection of non-small-cell lung cancer (NSCLC), based on the drug sensitivity test.

METHODS

Patients with resectable c-stage IB-IIIA NSCLC were registered between 2005 and 2010. We performed the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) on a fresh surgical specimen to assess in vitro chemosensitivity and evaluated the prognostic outcome after adjuvant chemotherapy with carboplatin/paclitaxel based on the CD-DST.

RESULTS

Among 92 registered patients, 87 were eligible for inclusion in the analysis. The success rate of CD-DST was 86% and chemosensitivity to carboplatin and/or paclitaxel was evident in 57 (76%) of the 75 patients. Adjuvant chemotherapy was completed in 22 (73%) of 30 patients. The 5-year overall survival rates were 71, 73, and 75% for all, CD-DST success, and chemosensitive patients, respectively. The 5-year disease-free survival and overall survival rates of the chemosensitive patients who completed adjuvant chemotherapy using carboplatin/paclitaxel were 68 and 82%, respectively. The 5-year disease-free survival and overall survival rates of the patients with stage II-IIIA chemosensitive NSCLC were 58 and 75%, respectively. Comparative analyses of the chemosensitive and non-chemosensitive/CD-DST failure groups showed no significant survival difference.

CONCLUSIONS

CD-DST can be used to evaluate chemosensitivity after lung cancer surgery; however, its clinical efficacy for assessing individualized treatment remains uncertain.

Impact of in vitro chemosensitivity test-guided platinum-based adjuvant chemotherapy on the surgical outcomes of patients with p-stage IIIA non-small cell lung cancer that underwent complete resection

The impact of in vitro chemosensitivity test-guided platinum-based adjuvant chemotherapy on the surgical outcomes of patients undergoing complete resection for locally advanced non-small cell lung cancer (NSCLC) has yet to be elucidated. In the present study, the utility of adjuvant chemotherapy based on the collagen gel droplet embedded culture drug sensitivity test (CD-DST) in patients with p (pathology)-stage IIIA NSCLC was retrospectively analyzed. A series of 39 patients that had received platinum-based adjuvant chemotherapy following complete resection between 2007 and 2012 were enrolled. Their surgical specimens were subjected to the CD-DST. The patients were subsequently classified into two groups on the basis of in vitro anti-cancer drug sensitivity data obtained using the CD-DST: The sensitive group (25 patients) were treated with regimens including one or two of the anti-cancer drug(s) that were indicated to be effective by the CD-DST, whereas the non-sensitive group (14 patients) were treated with chemotherapy regimens that did not include any CD-DST-selected anti-cancer drugs. There were no significant differences in the background characteristics of the two groups [including in respect of the pathological TN (tumor-lymph node) stage, tumor histology, epidermal growth factor receptor mutation status, the frequency of each chemotherapy regimen, and the number of administered cycles]. The 5-year disease-free survival (DFS) rate of the sensitive group was 32.3%, whereas that of the non-sensitive group was 14.3% (P=0.037). In contrast, no difference in overall survival (OS) was observed (P=0.76). Multivariate analysis revealed that adjuvant chemotherapy based on the CD-DST had a significant favorable effect on the DFS (P=0.01). Therefore, the present study has demonstrated that CD-DST data obtained from surgical specimens aid the selection of effective platinum-based adjuvant chemotherapy regimens for patients undergoing complete resection for p-stage IIIA NSCLC. The use of CD-DST-guided platinum-based regimens may have a beneficial impact on the DFS of such patients.

Influence of wound fluid on chemotherapy sensitivity in primary breast cancer cells

Objective

To investigate the effect of WF on chemotherapy sensitivities of primary breast cancer cells from breast cancer patients by using CD-DST.

Results

In general, the WF-treated cells showed remarkable increase in survival rates as compared to the control cells cultured without WF among different anticancer drug subgroups. This trend was generally observed in all the tumor cells from the premenopausal, postmenopausal, T2, N0, N1, luminal B, and TN patients.

Methods

The sensitivities of WF-treated primary breast cancer cells, from 21 patients who underwent a radical resection for breast cancer from September 2014 to July 2015, to anticancer drugs: EPI, CDDP, DOC, VNR, 5-FU+LV, and PAC, were obtained using CD-DST. The survival rates of the breast cancer cells were recorded and used to gauge the chemotherapeutic effect.

Conclusions

Surgery-induced WF promotes the drug resistance of primary breast cancer cells to chemotherapy, suggesting that surgery may have adverse effects on breast cancer patients. More studies are needed to investigate the key factors in WF that enhance the susceptibility to chemotherapy drugs.

Personalized in vitro cancer models to predict therapeutic response: Challenges and a framework for improvement

Personalized cancer therapy focuses on characterizing the relevant phenotypes of the patient, as well as the patient's tumor, to predict the most effective cancer therapy. Historically, these methods have not proven predictive in regards to predicting therapeutic response. Emerging culture platforms are designed to better recapitulate the in vivo environment, thus, there is renewed interest in integrating patient samples into in vitro cancer models to assess therapeutic response. Successful examples of translating in vitro response to clinical relevance are limited due to issues with patient sample acquisition, variability and culture. We will review traditional and emerging in vitro models for personalized medicine, focusing on the technologies, microenvironmental components, and readouts utilized. We will then offer our perspective on how to apply a framework derived from toxicology and ecology towards designing improved personalized in vitro models of cancer. The framework serves as a tool for identifying optimal readouts and culture conditions, thus maximizing the information gained from each patient sample.

Precision or Personalized Medicine for Cancer Chemotherapy: Is there a Role for Herbal Medicine

Although over 100 chemotherapeutic agents are currently available for the treatment of cancer patients, the overall long term clinical benefit is disappointing due to the lack of effectiveness or severe side effects from these agents. In order to improve the therapeutic outcome, a new approach called precision medicine or personalized medicine has been proposed and initiated by the U.S. National Institutes of Health. However, the limited availability of effective medications and the high cost are still the major barriers for many cancer patients. Thus alternative approaches such as herbal medicines could be a feasible and less costly option. Unfortunately, scientific evidence for the efficacy of a majority of herbal medicines is still lacking and their development to meet FDA approval or other regulatory agencies is a big challenge. However, herbal medicines may be able to play an important role in precision medicine or personalized medicine. This review will focus on the existing and future technologies that could speed the development of herbal products for treatment of resistant cancer in individual patients. Specifically, it will concentrate on reviewing the phenotypic (activity based) rather than genotypic (mechanism based) approach to develop herbal medicine useful for personalized cancer chemotherapy.

In Vitro Drug Sensitivity Tests to Predict Molecular Target Drug Responses in Surgically Resected Lung Cancer

BACKGROUND

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and anaplastic lymphoma kinase (ALK) inhibitors have dramatically changed the strategy of medical treatment of lung cancer. Patients should be screened for the presence of the EGFR mutation or echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene prior to chemotherapy to predict their clinical response. The succinate dehydrogenase inhibition (SDI) test and collagen gel droplet embedded culture drug sensitivity test (CD-DST) are established in vitro drug sensitivity tests, which may predict the sensitivity of patients to cytotoxic anticancer drugs. We applied in vitro drug sensitivity tests for cyclopedic prediction of clinical responses to different molecular targeting drugs.

METHODS

The growth inhibitory effects of erlotinib and crizotinib were confirmed for lung cancer cell lines using SDI and CD-DST. The sensitivity of 35 cases of surgically resected lung cancer to erlotinib was examined using SDI or CD-DST, and compared with EGFR mutation status.

RESULTS

HCC827 (Exon19: E746-A750 del) and H3122 (EML4-ALK) cells were inhibited by lower concentrations of erlotinib and crizotinib, respectively than A549, H460, and H1975 (L858R+T790M) cells were. The viability of the surgically resected lung cancer was 60.0 ± 9.8 and 86.8 ± 13.9% in EGFR-mutants vs. wild types in the SDI (p = 0.0003). The cell viability was 33.5 ± 21.2 and 79.0 ± 18.6% in EGFR mutants vs. wild-type cases (p = 0.026) in CD-DST.

CONCLUSIONS

In vitro drug sensitivity evaluated by either SDI or CD-DST correlated with EGFR gene status. Therefore, SDI and CD-DST may be useful predictors of potential clinical responses to the molecular anticancer drugs, cyclopedically.

Exploratory phase II trial in a multicenter setting to evaluate the clinical value of a chemosensitivity test in patients with gastric cancer (JACCRO-GC 04, Kubota memorial trial)

BACKGROUND

Although postoperative adjuvant chemotherapy with S-1, an oral fluoropyrimidine, has become a standard of care for gastric cancer in Japan, nonresponders may suffer from the cost and adverse reactions without clinical benefit. This multicenter exploratory phase II trial was conducted to see whether a chemosensitivity test, the collagen gel droplet embedded culture drug sensitivity test (CD-DST), can adequately select patients for chemotherapy.

METHODS

The CD-DST using four different concentrations of 5-fluorouracil was conducted with resected specimens from preregistered patients who underwent gastrectomy with D2 or more extensive lymphadenectomy. Patients who were histopathologically confirmed to have stage II or greater disease without distant metastasis were eligible for final enrollment. All patients underwent protocol-specified adjuvant chemotherapy with S-1. Three-year relapse-free survival was compared between patients determined as sensitive by the CD-DST (responders) and those deemed insensitive (nonresponders). Appropriate cutoff values for in vitro growth inhibition were defined when the hazard ratio for relapse in responders and the log-rank P values were at their minimum.

RESULTS

Of the 311 patients enrolled, 14 were ineligible and 27 failed to start the protocol treatment. The CD-DST failed in 64 other patients, and survival analyses were conducted with the remaining 206 patients (39 stage II disease, 155 stage III disease, and 12 stage IV disease). The outcome of patients who were determined to be responders was significantly superior to that of nonresponders regardless of the 5-fluorouracil concentrations, although no differences in clinicopathologic characteristics were observed between the two groups, except for age.

CONCLUSIONS

The CD-DST identified those who benefit from adjuvant chemotherapy. It deserves further evaluation in the setting of a prospective randomized trial. ClinicalTrials.gov identifier: NCT00287755.

Patient-derived xenografts from non-small cell lung cancer brain metastases are valuable translational platforms for the development of personalized targeted therapy

PURPOSE

The increasing prevalence of distant metastases from non-small cell lung cancer (NSCLC) indicates an urgent need for novel therapeutic modalities. Brain metastasis is particularly common in NSCLC, with severe adverse effects on clinical prognosis. Although the molecular heterogeneity of NSCLC and availability of various targeted agents suggest personalized therapeutic approaches for such brain metastases, further development of appropriate preclinical models is needed to validate the strategies.

EXPERIMENTAL DESIGN

We established patient-derived xenografts (PDX) using NSCLC brain metastasis surgical samples and elucidated their possible preclinical and clinical implications for personalized treatment.

RESULTS

NSCLC brain metastases (n = 34) showed a significantly higher successful PDX establishment rate than primary specimens (n = 64; 74% vs. 23%). PDXs derived from NSCLC brain metastases recapitulated the pathologic, genetic, and functional properties of corresponding parental tumors. Furthermore, tumor spheres established in vitro from the xenografts under serum-free conditions maintained their in vivo brain metastatic potential. Differential phenotypic and molecular responses to 20 targeted agents could subsequently be screened in vitro using these NSCLC PDXs derived from brain metastases. Although PDX establishment from primary NSCLCs was significantly influenced by histologic subtype, clinical aggressiveness, and genetic alteration status, the brain metastases exhibited consistently adequate in vivo tumor take rate and in vitro tumor sphere formation capacity, regardless of clinical and molecular conditions.

CONCLUSIONS

Therefore, PDXs from NSCLC brain metastases may better represent the heterogeneous advanced NSCLC population and could be utilized as preclinical models to meet unmet clinical needs such as drug screening for personalized treatments.

Personalized in vitro cancer modeling - fantasy or reality?

With greater technological advancements and understanding of pathophysiology, “personalized medicine” has become a more realistic goal. In the field of cancer, personalized medicine is the ultimate objective, as each cancer is unique and each tumor is heterogeneous. For many decades, researchers have relied upon studying the histopathology of tumors in the hope that it would provide clues to understanding the pathophysiology of cancer. Current preclinical research relies heavily upon two-dimensional culture models. However, these models have had limited success in recreating the complex interactions between cancer cells and the stroma environment in vivo. Thus, there is increasing impetus to shift to three-dimensional models, which more accurately reflect this phenomenon. With a more accurate in vitro tumor model, drug sensitivity can be tested to determine the best treatment option based on the tumor characteristics. Many methods have been developed to create tumor models or “tumoroids,” each with its advantages and limitations. One significant problem faced is the replication of angiogenesis that is characteristic of tumors in vivo. Nonetheless, if three-dimensional models could be standardized and implemented as a preclinical research tool for therapeutic testing, we would be taking a step towards making personalized cancer medicine a reality.

Stratified phase II trial to establish the usefulness of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST) for advanced gastric cancer

BACKGROUND

We conducted a multicenter phase II trial to assess the suitability of three types of chemotherapy (docetaxel plus S-1, irinotecan plus S-1, or S-1 alone) for patients with advanced gastric cancer by means of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST). To our knowledge, this is the first multicenter clinical trial that has employed CD-DST to choose anticancer agents for the treatment of advanced gastric cancer.

METHODS

Subjects (n = 64) were patients with advanced or recurrent gastric cancer. Patients were allocated to one of the treatment regimens on the basis of CD-DST results. Outcome of the patients was compared between the groups deemed chemosensitive or chemoresistant by the CD-DST.

RESULTS

Thirty-three patients showed high sensitivity (T/C ratio <60 %) to at least one type of anticancer agent (sensitive group), and 31 showed low sensitivity (T/C ratio ≥60 %) to all agents (resistant group). Specifically, the 1-year survival rate was significantly higher in the sensitive group (78.5 %; 95 % CI, 67.2-94.7 %) than in the resistant group (54.7 %; 95 % CI, 38.7-74.3 %; P = 0.019), whereas time to progression (TTP) was significantly longer in the sensitive group (59.8 %; 95 % CI, 48.2-81.7 %) than in the resistant group (30.0 %; 95 % CI 13.6-46.4 %; P = 0.023). Median survival time was also significantly longer in the sensitive group (15.5 months; 95 % CI, 12.8-18.2) than in the resistant group (12.5 months; 95 % CI, 10.2-14.9; P = 0.038).

CONCLUSIONS

CD-DST predicts the outcome of patients undergoing chemotherapy for advanced gastric cancer, presumably through evaluating chemosensitivity.

ABCC3 as a marker for multidrug resistance in non-small cell lung cancer

Multidrug resistance (MDR) contributes to the failure of chemotherapy and high mortality in non-small cell lung cancer (NSCLC). We aim to identify MDR genes that predict tumor response to chemotherapy. 199 NSCLC fresh tissue samples were tested for chemosensitivity by MTT assay. cDNA microarray was done with 5 samples with highest resistance and 6 samples with highest sensitivity. Expression of ABCC3 mRNA and protein was detected by real-time PCR and immunohistochemisty, respectively. The association between gene expression and overall survival (OS) was examined using Cox proportional hazard regression. 44 genes were upregulated and 168 downregulated in the chemotherapy-resistant group. ABCC3 was one of the most up-regulated genes in the resistant group. ABCC3-positive expression correlated with lymph node involvement, advanced TNM stage, more malignant histological type, multiple-resistance to anti-cancer drugs, and reduced OS. ABCC3 expression may serve as a marker for MDR and predictor for poor clinical outcome of NSCLC.

Prediction of chemotherapeutic response in unresectable non-small-cell lung cancer (NSCLC) patients by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium (MTS) assay

BACKGROUND

Selecting chemotherapy regimens guided by chemosensitivity tests can provide individualized therapies for cancer patients. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium, inner salt (MTS) assay is one in vitro assay which has become widely used to evaluate the sensitivity to anticancer agents. The aim of this study was to evaluate the clinical applicability and accuracy of MTS assay for predicting chemotherapeutic response in unresectable NSCLC patients.

METHODS

Cancer cells were isolated from malignant pleural effusions of patients by density gradient centrifugation, and their sensitivity to eight chemotherapeutic agents was examined by MTS assay and compared with clinical response.

RESULTS

A total of 37 patients participated in this study, and MTS assay produced results successfully in 34 patients (91.9%). The sensitivity rates ranged from 8.8% to 88.2%. Twenty-four of 34 patients who received chemotherapy were evaluated for in vitro-in vivo response analysis. The correlation between in vitro chemosensitivity result and in vivo response was highly significant (P=0.003), and the total predictive accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for MTS assay were 87.5%, 94.1%, 71.4%, 88.9%, and 83.3%, respectively. The in vitro sensitivity for CDDP also showed a significant correlation with in vivo response (P=0.018, r=0.522).

CONCLUSION

MTS assay is a preferable in vitro chemosensitivity assay that could be use to predict the response to chemotherapy and select the appropriate chemotherapy regimens for unresectable NSCLC patients, which could greatly improve therapeutic efficacy and reduce unnecessary adverse effects.

Differences in chemosensitivity between primary and paired metastatic lung cancer tissues: In vitro analysis based on the collagen gel droplet embedded culture drug test (CD-DST)

BACKGROUND

To elucidate the differences in chemosensitivity to anticancer drugs between primary and metastatic lesions in non-small cell lung cancer (NSCLC) patients, we examined the in vitro chemosensitivities of surgically resected NSCLC tissues.

METHODS

A total of 32 specimens were enrolled: 26 specimens of primary lesions paired with metastases in the lymph node, 3 specimens of primary lesions paired with metastases in the adrenal gland, and 3 specimens of primary lesions paired with metastases in the lung. The collagen gel droplet embedded culture drug test (CD-DST) was applied to examine the sensitivity of the tissues to anticancer drugs, including cisplatin, gemcitabine, vinorelbine, docetaxel and 5-fluorouracil.

RESULTS

The degree of in vitro sensitivity to each anticancer drug varied between the primary and metastatic lesions. The sensitivity of the paired metastatic lesions was significantly lower than that of the primary lesions only for gemcitabine (P=0.029), vinorelbine (P=0.012), and docetaxel (P=0.009). The incidence of cases diagnosed as CD-DST-sensitive among the paired metastatic lesions was significantly lower than that for the primary lesions for vinorelbine (P=0.035) or docetaxel (P=0.022). The difference in the sensitivity to gemcitabine between the primary and paired non-lymphatic metastases was clearer than that between the primary lesion and paired lymph node metastases.

CONCLUSIONS

The sensitivities of the paired metastatic lesions to some anticancer drugs were significantly lower than those of the primary lesions. When performing chemotherapy based on CD-DST data using primary tumors from patients with postoperative recurrence, an appropriate regimen can be selected by carefully considering these differences.

Establishment of primary mouse lung adenocarcinoma cell culture

Lung cancer is the most common malignant disease worldwide and is the leading cause of death from cancer. Primary cultures derived from lung cancer are essential for understanding abnormal growth function in lung epithelia. In this study, 2 out of 5 primary lung adenocarcinoma cultures derived from DNA repair-deficient mice were established and characterised using electron microscopy and immunostaining. Results of the tumourigenicity tests confirmed that these primary cells are tumourigenic. In conclusion, an effective primary culture method provides a tool for clinical antitumour drug testing.