Occurrence of a multidrug-resistant phenotype in human lung xenografts.

The intrinsic sensitivity of a panel of 8 human epidermoid lung cancer xenografts to vincristine and actinomycin D has been examined and the cross-resistance patterns of the most vincristine-resistant and vincristine-sensitive tumour line were tested to a variety of other drugs, including radiation. The results demonstrate that xenograft lines derived from human lung tumours not previously treated with chemotherapy exhibit a similar general pattern of cross-resistance to the drugs vincristine, actinomycin D and adriamycin as is observed in human cell lines and in animal models selected for resistance to these drugs. It is also shown that intrinsic resistance to vincristine can be partially overcome by verapamil. This may indicate a potential role of this substance in circumventing clinically observed drug resistance

P-glycoprotein and glutathione S-transferase pi in childhood acute lymphoblastic leukaemia.

Blast cells obtained from 104 children with untreated acute lymphoblastic leukaemia were analysed for the expression of P-glycoprotein (P-170) and glutathione S-transfer pi (GST-pi) using immunohistochemistry. Expression of P-170 was detected in 36 of 104 patients (35%) and increased GST-pi was seen in 52 patients (50%). Coexpression of both resistance proteins was observed in 22 leukaemias (21%), whereas no evidence of the resistance markers was found in 38 cases (37%). In patients with P-170-positive leukaemic cells, a significantly lower probability of remaining in first continuous complete remission (CCR) was observed when compared with patients with P-170-negative tumours (P < 0.05). However, only a trend for a more frequent expression of P-170 was found in the leukaemic cells of patients who experienced relapses (P = 0.099). Overexpression of GST-pi was correlated with a higher relapse rate (P = 0.001) and a lower probability of remaining in first CCR (P = 0.01). Expression of P-170 and GST-pi was independent of sex, FAB type, immunological subtype and initial blast cell count. The multivariate analysis indicated that only the expression of P-170 is an unfavourable prognostic factor for children with acute lymphoblastic leukaemia in addition to the prognostic clinical factors

Association of vascular endothelial growth factor expression with intratumoral microvessel density and tumour cell proliferation in human epidermoid lung carcinoma.

Vascular endothelial growth factor (VEGF) expression, vascularisation and tumour cell proliferation were analysed in 91 human epidermoid lung carcinomas using immunohistochemistry. A polyclonal anti-VEGF antibody was used for VEGF expression, a polyclonal antibody directed against human von Willebrand factor (factor VIII) to identify blood vessels and the proliferating cell nuclear antigen (PCNA) as a marker for proliferating cells. Positive staining for VEGF was obtained in 54 out of 91 cases (59%), the number of blood vessels varied from zero to 64 counts (mean 9.4) and the proportion of PCNA-positive cells varied from 1.3% to 72.1% (mean 25.2%). The mean PCNA labelling index and mean microvessel count in VEGF-positive tumours were significantly higher than those in VEGF-negative tumours (Wilcoxon rank sum test, P<0.0001; p<0.05). In addition, PCNA labelling index significantly increased with increasing VEGF expression (Jonckheere test, P<0.0001). In contrast, no association was found between PCNA labelling index and tumour vascularity (r=0.07, P=0.48). The close correlation of VEGF expression with tumour cell proliferation and microvessel density suggests that VEGF acts both as an autocrine growth factor and as stimulator for angiogenesis. However, tumour cell proliferation and microvessel growth and/or density may be regulated by separate mechanisms

Overexpression of P-glycoprotein and glutathione S-transferase-pi in resistant non-small cell lung carcinomas of smokers.

Ninety-four human non-small cell lung carcinomas (NSCLC) of previously untreated patients were analysed for the presence of P-glycoprotein (P-170) and glutathione S-transferase-pi (GST-pi) by means of immunohistochemistry. The expression of P-170 and GST-pi was compared with the results of doxorubicin resistance of the tumours in vitro and the smoking habits of the patients. A significant relationship between smoking habits of the patients and resistance of NSCLC was found (P = 0.007). Of the 72 tumours of smokers 57 (= 79%) were resistant, whereas of the 22 tumours of non-smokers only 11 (= 50%) showed resistance. Identical results were obtained when the analysis was restricted to patients with epidermoid lung carcinomas (P = 0.004). In contrast to these data, there exists no relationship between resistance and smoking for adenocarcinomas of the lung. Forty-two (= 58%) out of the 72 NSCLC of smokers expressed P-170, whereas out of 22 tumours of non-smokers only two tumours (= 9%) showed P-170 expression (P less than 0.0001). Similar results were obtained with epidermoid carcinomas (P = 0.004) and adenocarcinomas (P = 0.027). Fifty (= 69%) of 72 NSCLC of smokers revealed expression of GST-pi, whereas only nine (= 41%) of 22 tumours of non-smokers showed GST-pi expression (P = 0.015). Significant correlations also exist between resistance in vitro and expression of P-170 (P less than 0.0001) or expression of GST-pi (P less than 0.0001). Furthermore, a significant relationship between both proteins could be demonstrated (P less than 0.0001)

Prognostic value of ERBB-1, VEGF, cyclin A, FOS, JUN and MYC in patients with squamous cell lung carcinomas.

Patients with previously untreated squamous cell lung carcinomas were evaluated to see if combining the expression of molecular and cellular factors with the most important clinical prognostic factors could improve the diagnostic ability to predict prognosis. For this reason, immunohistochemistry was used to examine the squamous cell lung carcinomas from 121 patients for their expression of ERBB-1, vascular endothelial growth factor (VEGF), cyclin A, FOS, JUN and MYC. Median survival was shorter for patients with ERBB-1-, VEGF-, cyclin A-, FOS-, or JUN-positive tumours. For those patients with positive lymph node involvement, the survival times were also shorter in the VEGF-positive, cyclin A-positive and FOS-positive groups. Multivariate analysis independently demonstrated a significant prognostic value for lymph node involvement, VEGF and FOS

Development of drug resistance in a human epidermoid lung carcinoma xenograft line.

The development of resistance to vincristine, actinomycin D and cisplatin has been examined in a human epidermoid lung carcinoma xenograft line (HXL 55) growing in nude mice. Treatment of HXL 55 with 1 mg kg-1 vincristine or 0.5 mg kg-1 actinomycin D once in each in vivo passage resulted in a rapid reduction in tumour responsiveness to these drugs. A partial resistance was already acquired at the 2nd transplant generation. In contrast, a gradual decrease in therapeutic response was observed with 10 mg kg-1 cisplatin. Irradiation with a local dose of 10 Gy induced no resistance. The three induced drug-resistant sublines were characterized in terms of the time course of development of resistance, the degree of induced resistance, cross-resistance, growth rate and stability of the phenotype

Growth of human bronchial carcinomas in nude mice.

Two hundred and thirteen lung tumours of primary site and 42 metastases were heterotransplanted into nude mice with an overall success rate of 44%. There were differences in success between the histological types. Squamous cell and adenocarcinoma had the highest success rate (51% and 43%, respectively) whereas large cell and small cell carcinoma had a lower success rate (38% for both). The average volume doubling times in the first passage in nude mice ranged from 8.2 in large cell carcinomas to 18.9 days in adenocarcinomas. In subsequent passages an increase in growth rate was found, the overall average doubling time falling from 14.5 days in the first passage to 7.1 days in the second passage. In a study with 171 non-small cell lung carcinomas (NSCLC), the growth data in nude mice were correlated with the clinical data of the corresponding patients. A relationship between the growth parameters in nude mice and prognosis of patients could not be found

P-glycoprotein expression in treated and untreated human breast cancer.

The expression of P-glycoprotein in primary and recurrent human breast cancer was investigated by means of immunohistochemistry, using a monoclonal antibody (C219) and the streptavidin-biotin-peroxidase method. Twelve patients received no chemotherapeutic treatment. The other 11 patients were treated with chemotherapy, and all developed clinical resistance to it. No or only minimal reactivity was found in specimens coming from the untreated patients (12 cases) or from patients treated with substances not involved in the multidrug resistance phenomenon (four cases). In contrast, three out of seven tumours from patients treated with multidrug resistance related substances showed clear reactivity (positive staining in more than 20% of the tumour cells). In one of these cases, where specimens of the tumour could be studied before and after treatment, an association between the latter and expression of P-glycoprotein was suggested. Finally, this marked expression of P-glycoprotein only took place in tumours treated over a longer space of time (five courses or more of multidrug resistance related chemotherapy)