In vitro chemosensitivity test of human gastric carcinomas using collagen gel matrix

Collagen gel matrix assay as an in vitro chemosensitivity test for malignant astrocytic tumors

BACKGROUND

The efficacy of individual chemotherapy based on chemosensitivity has scarcely been studied.

METHODS

We examined the chemosensitivites for four anticancer agents - 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3 (2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), carboplatin, cisplatin, and etoposide - of 43 malignant astrocytic tumors (21 anaplastic astrocytomas and 22 glioblastomas) by using a collagen gel matrix assay, and we also determined the survival periods of the tumor-bearing patients. The chemosensitivity was evaluated in terms of the growth inhibition rate, using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) method.

RESULTS

For the anaplastic astrocytomas, the mean growth inhibitory rate was 33.2% with cisplatin, 37.2% with carboplatin, 28.0% with ACNU, and 24.8% with etoposide. For the glioblastomas, these rates were 36.9%, 42.3%, 23.2%, and 34.8%, respectively. The median overall and progression-free survivals of anaplastic astrocytoma-bearing patients who had undergone chemotherapy with two anticancer drugs, both of which showed significant anticancer activity (growth inhibitory rate >30%) were significantly longer than those of the patients who had been treated with two drugs, one or both of which did not show significant anticancer activity. On the other hand, there was no significant difference in the overall or the progression-free survivals in the two corresponding groups of glioblastoma-bearing patients.

CONCLUSION

The collagen gel matrix assay is clinically useful to determine in vitro chemosensitivity that reflects in vivo chemosensitivity. Individual chemotherapy for malignant astrocytic tumors, based on chemosensitivity data, could contribute to longer survival, particularly in anaplastic astrocytoma-bearing patients.

In vitro chemosensitivity test for human genito-urinary tumors using collagen gel matrix

BACKGROUND

Although the aim of chemosensitivity tests is to predict the efficacy of anticancer agents for individual patients, no generally accepted assay has been established.

METHODS

A chemosensitivity test was conducted for solid tumors with an organ culture system using collagen gel matrix (CGM). Seventy-five samples of transitional cell carcinoma (TCC), 20 of germ cell tumor (GCT) and 13 of renal cell carcinoma (RCC) were used for the chemosensitivity test, and 20 patients were treated with anticancer drugs on the basis of the test results.

RESULTS

Positive rates of anticancer drugs for the 75 TCC samples were 64.9% for carboplatin, 63.4% for cisplatin, 32.1% for etoposide, 19.7% for THP-adriamycin, 16.7% for vinblastine, and 12.3% for methotrexate, indicating that positive rates of the latter three agents consisting of an MVAC regimen were unexpectedly low. The GCT had higher positive rates than the other cancers while RCC had the lowest. In 20 eligible patients (seven patients with bladder tumors and 13 with GCT), the true positive and true negative rates were 42% (5/12) and 75% (6/8), respectively, and the sensitivity and specificity were 71% (5/7) and 46% (6/13), resulting in a 55% (11/20) accurate predictive value.

CONCLUSION

Although predictive accuracy was moderate when combination chemotherapy was used, information about chemosensitivity may have some beneficial effect on the treatment of patients with invasive bladder cancer or advanced GCT, because insensitive drugs detected by the test could be deleted or replaced with more sensitive ones.

Novel models for human scirrhous gastric carcinoma in vivo

Human scirrhous gastric carcinoma, a diffusely infiltrating type of poorly differentiated gastric carcinoma also known as linitis plastica type carcinoma, is characterized by cancer cell infiltration and proliferation accompanied with extensive stromal fibrosis. We established two new gastric cancer cell lines, designated OUCM-8 and OCUM-11, which developed the characteristic biology of scirrhous gastric carcinoma upon orthotopic implantation in mice. Involvement of lymph nodes and liver metastasis was also found in both orthotopic models. Histologically, these orthotopic models showed proliferation with extensive fibrosis, resembling human scirrhous gastric cancer. Both cell lines were derived from ascites of patients with scirrhous gastric cancer. The growth of OCUM-8 and OCUM-11 cells following the addition of KGF, FGF, and EGF was increased significantly relative to untreated cells. An increase in the number of attached and spreading cells occurred following the addition of TGF-beta 1 in both cell lines. OCUM-11 cells showed microsatellite instability. Although subcutaneous scirrhous gastric cancer cells show medullary growth, most in vivo studies of scirrhous gastric cancer have used xenografted tumors implanted subcutaneously. Only in a few cases was it confirmed that these scirrhous gastric cancer cell lines retained the original histologic characteristics. Our orthotopic models should contribute to the elucidation of disease progression in situ and to the development of therapy for scirrhous gastric cancer.

Inhibitory Effects of 9-(4-Thio-.BETA.-D-ribo-pentofuranosyl)guanine on Tumor Growth and Angiogenesis

BACKGROUND

To find a nucleoside with anti-angiogenic activity, we tried to screen an active compound from our nucleoside library.

MATERIALS AND METHODS

The compound inhibiting the growth of human umbilical vein endothelial cell (HUVEC) induced by the conditioned medium of lung carcinoma cell line PC-9 was screened. The antitumor activity of the compound was evaluated against murine sarcoma S-180 implanted onto chick embryo chorioallantoic membrane (CAM).

RESULTS

9-(4-Thio-beta-D-ribo-pentofuranosyl)guanine (4'-thioguanosine) was found to be a potent inhibitor of the growth of HUVEC. The growth of S-180 implanted onto CAM was also inhibited by 4'-thioguanosine whereas the in vitro growth of S-180 was not inhibited. The administration of 4'-thioguanosine in mice caused unexpected side effect which suggested neurotoxicity.

CONCLUSIONS

Antitumor effect of 4'-thioguanosine on S-180 was suggested to be due to inhibition of tumor angiogenesis. Because of toxicity of 4'-thioguanosine in mice, further development of the derivatives which have lower toxicity is required.

Effective therapy for peritoneal dissemination in gastric cancer

Peritoneal dissemination is the most frequent cause of death from gastric cancer, accounting for death in 20% to 40% of patients. Preoperative intraperitoneal chemotherapy, peritonectomy, intraoperative chemohyperthermic perfusion, and early postoperative intraperitoneal chemotherapy are treatment modalities specifically designed to eliminate peritoneal dissemination and progression. Preoperative intraperitoneal chemotherapy is for containment of peritoneal free cancer cells, and also may facilitate complete eradication of visible peritoneal dissemination by peritonectomy. Further, complete cytoreduction can be achieved more often when peritonectomy is included in the surgical treatment of gastric cancer with peritoneal dissemination. Phase III data shows prolonged survival attributed to complete cytoreduction. Aggressive cytoreduction of peritoneal dissemination by peritonectomy can reduce residual tumor burden to micrometastases on the peritoneal surface that can be treated by intraoperative intraperitoneal chemotherapy and early postoperative intraperitoneal chemotherapy. Among all these modalities, surgical cytoreduction is probably the most important for survival benefit. If the surgical cytoreduction is visibly incomplete, prolonged survival cannot be expected, despite subsequent treatment. The surgeon's goal is to reduce the cancer cell burden to a microscopic level. Continued refinement of phase II studies is needed for maximal benefit and to standardize the technical and chemotherapeutic options of each modality.

Examination of in vitro chemosensitivity test using collagen gel droplet culture method with colorimetric endpoint quantification

To develop a simpler method of performing the collagen gel droplet-embedded culture drug sensitivity test (CD-DST), we examined the introduction of colorimetric quantitative determination of images for evaluation of anticancer effect against cancer cells alone in the presence of fibroblasts, based on differences in proliferative morphology and stainability with neutral red of cells within collagen gel drops determined using a video-microscope and NIH Image software. In examinations using a human cancer cell line and a fibroblast cell line, a high degree of linearity between number of cancer cells and image-optical density was found within the range of 10(2) - 10( 6) cells / droplet (r (2) = 0.933). Using NIH Image, fibroblast cells could be eliminated at a cut-off value of 128, and an immunocytochemical method demonstrated that the cells eliminated from the image were indeed fibroblasts, and those remaining were cancer cells. CD-DST was carried out with mixtures of cancer cells with fibroblasts at various ratios, and the feasibility of evaluating anticancer activity in cancer cells alone with no effect of fibroblasts at any mixing ratio was confirmed. In addition, for CD-DST of primary cell cultures of human lung cancers collected at the time of surgery, a high correlation between results obtained with the volume supplementation method, a current cell quantification method, and those with the imaging colorimetric quantification method was obtained (r = 0.933). These results indicate that introduction of imaging colorimetric quantification utilizing NIH Image makes CD-DST a quick and simple method that should be highly useful for clinical chemosensitivity testing using primary cell cultures of human cancers.

Effects of intraoperative chemohyperthermia in patients with gastric cancer with peritoneal dissemination

BACKGROUND

The most common cause of noncurative resection and recurrence is gastric cancer is peritoneal seeding. However, the results of treatment of peritoneal dissemination with chemotherapy have been poor with 5-year survival rates of 0%.

METHODS

A new in vitro thermochemosensitivity test was performed on gastric cancer cells obtained from 19 surgically resected specimens by using tetrazolium-based colorimetric assay (MTT assay). A novel treatment of the intraoperative chemohyperthermia was undertaken in 83 patients with gastric cancer with peritoneal dissemination. After aggressive resection of primary tumor, lymph nodes, and peritoneal metastases, warmed saline solution containing mitomycin C 30 mg, etoposide 150 mg, and cisplatin 300 mg was introduced into the peritoneal cavity via a closed circuit continuous hyperthermic peritoneal perfusion (CHPP) for 60 minutes to keep the abdominal temperature at 42 degree to 43 degrees C by means of a heat exchange mechanism.

RESULTS

The in vitro thermochemosensitivity test that 43 degrees C enhanced the cytotoxin effects on gastric cancer cells under clinically achievable drug concentrations. During CHPP, drug concentrations of cisplatin, mitomycin C, and etoposide in the perfusate remained statistically higher than in the peripheral venous circulation. Among 43 evaluable patients with residual peritoneal seeding, eight (19%) and nine (21%) exhibited complete response and partial response, respectively. The overall 1- and 5-year survival rates were 43% and 11%, respectively. Patients who underwent complete resection survived significantly longer than those with residual disease, and those with complete response had a significantly better prognosis than did those with partial response, and nonresponders. One-year survival rates with complete response, partial response or nonresponders were 88%, 27% and 22%, respectively. Five patients survived longer than 5 years.

CONCLUSIONS

Our triple treatment combining surgery and CHPP is an effective therapy for selected patients with gastric cancer with peritoneal dissemination.

Evaluation of antitumour effects of docetaxel (Taxotere) on human gastric cancers in vitro and in vivo

In vitro antitumour effects of docetaxel (Taxotere) were examined in nine cultured human gastric cancer cell lines and 18 clinical gastric cancer specimens. In vivo antitumour effects were examined in human gastric cancer xenografts in nude mice. The activity was compared with paclitaxel (Taxol). Docetaxel was more effective than paclitaxel in six of the nine cell lines and the effectiveness rates of docetaxel and paclitaxel were 56% (10/18) and 6% (1/17), respectively, in the clinical gastric cancer specimens. In vivo docetaxel showed superior antitumour effect on well differentiated (MKN-28), poorly differentiated (MKN-45) and undifferentiated (KKLS) gastric cancer xenografts. We conclude that docetaxel promises to be clinically active against gastric carcinomas.

Prophylaxis with intraoperative chemohyperthermia against peritoneal recurrence of serosal invasion-positive gastric cancer

Continuous hyperthermic peritoneal perfusion (CHPP) with a solution which contains 30 mg mitomycin C and 300 mg cisplatin has been introduced as a prophylactic treatment for peritoneal recurrence after curative resection of 79 advanced gastric cancers. The control group consisted of 81 patients with advanced gastric cancer who underwent curative surgery during the same period. CHPP was performed for 60 minutes by perfusing MMC- and CDDP-containing saline solutions warmed at 43.5 degrees C by a special CHPP device. In patients with pathologically confirmed serosal invasion-positive tumors, the survival rate of the CHPP group was significantly higher than that of the control group. A survival advantage for stage IV patients was also obtained by CHPP. However, there was no survival advantage between the CHPP group and the control group with serosal invasion-negative tumors. Adverse effects were observed in four patients who underwent CHPP: One developed severe bone marrow suppression, and transient hyperazotemia was observed in the other three. There was no difference in the incidence of mortality and morbidity between the two groups. These results indicate that CHPP is a safe, readily available prophylactic therapy for peritoneal recurrence after gastric cancer surgery.

Comparative study of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and tritiated thymidine in a chemosensitivity test using collagen gel matrix

An organ culture system using collagen gel matrix (CGM) was modified and established successfully as a rapid and convenient method for determination of anti-cancer drug sensitivities. The cell viability of a tumor fragment was measured by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to a colored formazan product, which allowed for quantitative and simple analysis. The sensitivities of KK-47 bladder tumor from nude mice to various anti-cancer drugs tested corresponded closely to those determined in the original CGM assay system using tritiated thymidine, which has a high clinical correlation. Our modified method can be used as a practical and highly reproducible chemosensitivity test in vitro.

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).