Tumor tissue is more sensitive to mitomycin C, carboquone, and aclacinomycin A than is adjacent normal tissue in vitro

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.

A feasibility study of adenosine triphosphate-based chemotherapy response assay (ATP-CRA) as a chemosensitivity test for lung cancer

PURPOSE

A chemosensitivity test can reflect the differences in responses of individual cancer patients to chemotherapeutic agents. The adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is an accurate method, which does not require a large amount of tissue specimen. So far, no studies have evaluated the utility of the ATP-CRA in Korea. Therefore, we investigated the clinical usefulness of the ATP-CRA in 53 patients with lung cancer.

MATERIALS AND METHODS

Tumor tissues were obtained from bronchoscopic biopsies or surgical resections. The validity of ATP-CRA was assessed focusing on the success rate, experimental error level (intraassay mean coefficient of variation [CV]) and reproducibility.

RESULTS

The overall success rate of ATP-CRA was 90.6% (48/53). Normal cells were effectively eliminated from the tumor tissues with the use of ficoll gradient centrifugation and immunomagnetic separation, which was confirmed using loss of heterozygosity analysis of the 3p deletion. The mean CV of ATP assays was 10.5+/-4.6%. The reproducibility of ATP assays was 94+/-3.8%. The results of the ATP assays were reported to physicians within 7 days of specimen collection. More than 6 anticancer drugs were tested on the tumor specimens obtained from bronchoscopic biopsies.

CONCLUSION

The ATP-CRA is a stable, accurate and potentially practical chemosensitivity test in patients with lung cancer.

Evaluation of in vitro chemosensitivity of antitumor drugs using the MTT assay in fresh human breast cancer

Practical criteria were developed in this paper for the purpose of evaluating chemosensitivity of fresh human breast cancer by the MTT assay. The survival rates at maximum inhibition (Imax %) and the concentrations of drugs which caused fifty percent reduction in absorbance compared to baseline values (IC50) of 175 samples of 10 anti-tumor drugs were evaluated by logistic analyses of the dose-response curves. Distributions of Imax% appeared as normal curves, while those of the IC50 significantly deviated from normal distribution (p < 0.0001). We assessed the in vitro chemosensitivity by comparing the Imax % of each drug on individual samples with the mean Imax % + SD which was obtained from the Imax% of 175 samples. If the individual Imax % > mean Imax % + SD. we thought the tumor sample was resistant to this drug. If the Imax % < or = mean Imax % + SD, we would compare its IC50 with Q50 which was used as a cutoff point for in vitro chemosensitivity of anti-tumor drugs. The in vitro chemosensitivity could be graded as sensitive (Q1-Q25), intermediate (Q26-Q75), and resistant (Q76-Q100) by means of percentile method. If the individual IC50 > or = Q76, the tumor sample would be defined as resistant. If the individual IC50 < or = Q25, it would be defined as sensitive. In the range of Q26-Q75, we used Q50 as a cutoff point between relative sensitivity and relative resistance. Preliminary results showed that the in vitro chemosensitivity to different anti-tumor drugs determined by these criteria were consistent with the clinical response in 83 advanced breast cancer patients.

Chemosensitivity testing of fresh human gastric cancer with highly purified tumour cells using the MTT assay

A major problem associated with the chemosensitivity testing of fresh human tumour cells using the MTT assay is the contamination of nonmalignant cells in the tumour tissues. Highly purified fresh human gastric cancer cells could be obtained from 43 solid tumours and eight malignant ascites for the MTT assay. The success rate of the MTT assay was 87.9% (51 of the 58 cases), and the purity of tumour cells was greater than 90% after separation on Ficoll-Hypaque and Percoll discontinuous gradients in primary, or metastatic lesions, and also ascites. Cisplatin, mitomycin, and doxorubicin were more potent drugs than etoposide and 5-FU against gastric cancer cells. The chemosensitivity in differentiated cancer was equivalent to that in non-differentiated cancer. Twenty of the 51 patients with gastric cancer had evaluable lesions, and they received chemotherapy according to the results of the MTT assay using highly purified tumour cells. A clinical response was obtained in 12 of these 20 patients (response rate: 60.0%; five with complete response, seven with partial response).

Effect of mitomycin C on the uptake of photofrin II in a human colon adenocarcinoma cell line

Flow cytometry (FCM) was used to investigate the effect of mitomycin C (MC) on the cellular uptake of Photofrin II (PII) in a cultured human colon adenocarcinoma cell line (WiDr). The surface area of the cells increased as they passed through the cell cycle from G0/G1 to G2/M phase. MC retarded the cells in G2/M phase and enhanced the surface area of the cells. A 1.3-2.3-fold increase in the cell surface area and a 1.3-2.7-fold increase in the cellular uptake of PII in the tumor cells was observed after 2 h-8 h incubation with MC. Within each sample, an almost linear relationship between the intensity of PII fluorescence in the cells and the surface area of the cells was found. However, for the cells incubated with MC the surface area was not the only determinant of PII uptake. Effects of MC on the cell cycle, the cell surface area and the permeability of the cell membrane are suggested as possible reasons for the increase of cellular uptake of PII in the tumor cells.

Chemosensitivity testing with highly purified fresh human tumour cells with the MTT colorimetric assay

A major problem associated with the succinate dehydrogenase inhibition (SDI) test using tetrazolium dye (MTT) as a cancer chemosensitivity testing is the contamination of non-malignant cells in the tumour tissues. Highly purified fresh human tumour cells from 44 solid tumours and 24 malignant ascites were used for the MTT assay. The purity of tumour cells was greater than 90% after separation on Ficoll-Hypaque and Percoll discontinuous gradients. The OD570 obtained from tumour cells alone was higher than that from non-malignant cells. The chemosensitivity of tumour cells was distinct from that of non-malignant cells. Moreover, the chemosensitivity of highly purified tumour cells was also distinct from that of non-purified cells just separated from tumour tissues. 31 of the 68 patients had evaluable lesions, and received cancer chemotherapy according to the results of MTT assay using highly purified tumour cells. A clinical response was obtained in 10 of the 31 patients (response rate = 32.3%, 5 complete responses, 5 partial responses).

The influence of stromal cells on the MTT assay (I)--In vitro chemosensitivity of the tumor and stromal cells to mitomycin C

To clarify the influence of stromal cells on the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assay (MTT assay), a gastric carcinoma cell line (KATO-III) and a human fibroblast cell line (IMR-90) were subjected to a colorimetric assay, in which the chemosensitivity KATO-III was found to be highly sensitive to mitomycin C at 10 micrograms/ml, whereas IMR-90 was insensitive to mitomycin C at the same concentration. When the mixtures of these two cell lines were tested by the assay, a mixture of more than 25 per cent stromal cells reduced the sensitivity of KATO-III to mitomycin C. This suggested that the stromal cells in fresh surgical specimens might reduce the apparent sensitivity of the tumor cells.

Primary and metastatic liver lesions of clinical colorectal cancer differ in chemosensitivity

The succinate dehydrogenase inhibition (SDI) test was used to examine eight pairs of samples obtained simultaneously from primary colorectal cancers and metastatic liver lesions. The chemosensitivity of the metastatic lesions to six antitumour drugs, carboquone (CQ), adriamycin (ADM), mitomycin C (MMC), aclacinomycin A (ACR), cisplatin (DDP), and 5-fluorouracil (5-FU), differed from that of the primary lesions - the metastatic lesions were less sensitive to all these drugs. There were no correlations of chemosensitivities between the primary and the metastatic lesions (r = -0.4331-0.4857). Thus, in patients with liver metastasis from a primary colorectal cancer, treatment with these drugs may not be so effective. When selecting antitumour drugs for metastatic liver lesions of colorectal cancer, the chemosensitivity of the primary tumour should first be assessed.

Chemosensitivity test for carcinoma of digestive organs

For the chemosensitivity for carcinoma of digestive organs, gastric, colorectal, and hepatic cancer tissues were examined using in vitro succinate dehydrogenase inhibition (SDI) test and in vivo subrenal capsule (SRC) assay. The chemosensitivity varied in the tissue. The origin of an organ tumor, histological differentiation, and difference of primary or metastatic lesions are critical for determining chemosensitivity. Biochemical analysis shows that antitumor drugs have an increased susceptibility in tissues with high activity of pyrimidine nucleotide synthesis.