Dexamethasone desensitizes hepatocellular and colorectal tumours toward cytotoxic therapy

The glucocorticoid dexamethasone is frequently used as co-treatment in cytotoxic cancer therapy, e.g. to prevent nausea, to protect normal tissue or for other reasons. While the potent pro-apoptotic properties and the supportive effects of glucocorticoids to tumour therapy in lymphoid cells are well studied, the impact to cytotoxic treatment of colorectal and hepatocellular carcinoma is unknown. We tested apoptosis-induction, viability, tumour growth and protein expression using 8 established cell lines, 18 surgical specimen and a xenograft on nude mice. In the presence of dexamethasone we found strong inhibition of apoptosis in response to 5-FU, cisplatin, gemcitabine or gamma-irradiation, enhanced viability and tumour growth of colorectal and hepatocellular carcinomas. No correlation with age, gender, histology, TNM, the p53 status and induction of therapy resistance by dexamethasone co-treatment could be detected. These data show that glucocorticoid-induced resistance occurs not occasionally but is common in colorectal and hepatocellular carcinomas implicating that the use of glucocorticoids may be harmful for cancer patients.

Dexamethasone-induced cisplatin and gemcitabine resistance in lung carcinoma samples treated ex vivo

Chemotherapy for lung cancer not only has severe side effects but frequently also exhibits limited, if any clinical effectiveness. Dexamethasone (DEX) and similar glucocorticoids (GCs) such as prednisone are often used in the clinical setting, for example, as cotreatment to prevent nausea and other symptoms. Clinical trials evaluating the impact of GCs on tumour control and patient survival of lung carcinoma have never been performed. Therefore, we isolated cancer cells from resected lung tumour specimens and treated them with cisplatin in the presence or absence of DEX. Cell number of viable and dead cells was evaluated by trypan blue exclusion and viability was measured by the MTT-assay. We found that DEX induced resistance toward cisplatin in all of 10 examined tumour samples. Similar results were found using gemcitabine as cytotoxic drug. Survival of drug-treated lung carcinoma cells in the presence of DEX was longlasting as examined 2 and 3 weeks after cisplatin treatment of a lung carcinoma cell line. These data corroborate recent in vitro and in vivo xenograft findings and rise additional concerns about the widespread combined use of DEX with antineoplastic drugs in the clinical management of patients with lung cancer.

Induction of apoptosis in experimental human B cell lymphomas by conditional TRAIL-expressing T cells

In the present study, we demonstrate the utility of a non-tumour-forming T-cell line for the inducible gene transfer of tumour necrosis factor (TNF)-related apoptosis-inducing ligand (Apo2L/TRAIL), which has been shown to selectively induce apoptosis in malignant but not in normal cells. To generate T cells inducible for TRAIL expression, we stably transfected Jurkat cells with TRAIL in the context of the Tet-On system. The switched on cells strongly expressed TRAIL mRNA, whose protein product was expressed on the cell surface. Paracrine induction of apoptosis in human target tumour cells was solely found for membrane-bound TRAIL. The Jurkat-TRAIL cells itself survived due to clonal selection of TRAIL-resistant cells. Jurkat-TRAIL cells had an additive effect with cytotoxic drugs in vitro, since cell death was enhanced. To elucidate the antitumoral activity of these Jurkat-TRAIL cells in vivo, we injected them intratumorally in xenografts of human Burkitt lymphomas. Switching on expression of TRAIL by adding tetracycline to the drinking water of the mice strongly reduced tumour growth by apoptosis in a caspase-dependent manner. Thus, non-tumour-forming T-cell lines offer a novel method for gene transfer and inducible expression of TRAIL in tumour therapy.

Protein expression profiles indicative for drug resistance of non-small cell lung cancer

Data obtained from multiple sources indicate that no single mechanism can explain the resistance to chemotherapy exhibited by non-small cell lung carcinomas. The multi-factorial nature of drug resistance implies that the analysis of comprising expression profiles may predict drug resistance with higher accuracy than single gene or protein expression studies. Forty cellular parameters (drug resistance proteins, proliferative, apoptotic, and angiogenic factors, products of proto-oncogenes, and suppressor genes) were evaluated mainly by immunohistochemistry in specimens of primary non-small cell lung carcinoma of 94 patients and compared with the response of the tumours to doxorubicin in vitro. The protein expression profile of non-small cell lung carcinoma was determined by hierarchical cluster analysis and clustered image mapping. The cluster analysis revealed three different resistance profiles. The frequency of each profile was different (77, 14 and 9%, respectively). In the most frequent drug resistance profile, the resistance proteins P-glycoprotein/MDR1 (MDR1, ABCB1), thymidylate-synthetase, glutathione-S-transferase-pi, metallothionein, O6-methylguanine-DNA-methyltransferase and major vault protein/lung resistance-related protein were up-regulated. Microvessel density, the angiogenic factor vascular endothelial growth factor and its receptor FLT1, and ECGF1 as well were down-regulated. In addition, the proliferative factors proliferating cell nuclear antigen and cyclin A were reduced compared to the sensitive non-small cell lung carcinoma. In this resistance profile, FOS was up-regulated and NM23 down-regulated. In the second profile, only three resistance proteins were increased (glutathione-S-transferase-pi, O6-methylguanine-DNA-methyltransferase, major vault protein/lung resistance-related protein). The angiogenic factors were reduced. In the third profile, only five of the resistance factors were increased (MDR1, thymidylate-synthetase, glutathione-S-transferase-pi, O6-methylguanine-DNA-methyltransferase, major vault protein/lung resistance-related protein).

Ocular bioavailability of ciprofloxacin in sustained release formulations

A novel sustained release delivery system of ciprofloxacin for the eye was developed. The system consists of a viscosity enhancer (carbopol gel or hydroxypropylmethylcellulose solution) plus a penetration enhancer (dodecylmaltoside) to overcome penetration barriers and loss due to wash-out and thus achieve the desired ciprofloxacin ocular absorption. The present studies were designed to assess the ocular penetration and bioavailability of ciprofloxacin in sustained release formulations. In vitro studies in rabbits indicated an approximate 10-fold increase in drug penetration through the rabbit cornea using the penetration enhancer, dodecylmaltoside. In vivo bioavailability studies demonstrate that these formulations provided a long drug duration in the cornea. After administration of a single topical dose of ciprofloxacin (0.3%/30 microL), corneal levels greater than the Minimum Inhibitory Concentration (MIC90) (0.5 microg/g) were observed through eight hours. These sustained release formulations delivered 10-fold more drug into the aqueous humor than the standard solution formulation. Maximum ciprofloxacin concentrations in the aqueous humor (0.5-0.7 microg/mL) were attained between one and two hours after dosing. Using these sustained release formulations, ciprofloxacin can penetrate to the anterior chamber of the eye in concentrations that are inhibitory for most gram-negative and gram-positive organisms. These topical ocular formulations have prophylactic utility for prevention of post-surgical infection, offering greater efficacy and safety than currently available treatments.

Role of angiogenesis in drug resistance

Tumor angiogenesis seems to be an important factor in determining therapeutic effectiveness and patient prognosis. An abundance of data on tumor angiogenesis is available and it clearly shows that most human solid tumors are heterogeneously vascularized and oxygenated and contain hypoxic regions. Such regions and areas of reduced vascularization can affect the response to a variety of drugs. Direct measurements of angiogenesis in various types of tumors have, upon correlation of the data with therapeutic outcome, shown that a high vascular density is associated with a decreased response to therapy and short overall survival time. Therefore, the extent of tumor angiogenesis may well be an important factor contributing to the difficulty of successful therapy in certain tumor types.

Clinical estimation of the growth rate of lung cancer

It is well known that the growth rate of lung tumors is closely related to prognosis and is an important determinant of responsiveness to therapy and curability. In this study, the velocity of tumor growth was calculated by dividing the area of the lesion at presentation divided by the time elapsed since symptoms were first noted. This parameter was applied to a group of patients with lung cancer and the predictive value of the velocity of tumor growth was assessed. Survival expectancy was found to be closely related to the growth rate of the tumors. The median survival time of patients with more slowly growing tumors was 102 weeks, while that of patients with fast-growing tumors was 30 weeks (log-rank test, p=0.00001). Linear regression analysis between velocity of tumor growth and tumor cell proliferation as measured by the PCNA-labelling index revealed a significant correlation between these two parameters. In conclusion, the velocity of a tumor measured in this way is an independent and significant prognostic factor for patients with lung cancer and may be used to non-invasively assess lung cancer proliferation in vivo, identifying rapidly growing tumors with poor prognosis that could benefit from a more aggressive therapy.

Angiostatin expression in non-small cell lung cancer

Angiostatin, a potent inhibitor of angiogenesis, tumor growth, and metastasis, was examined in a panel of human lung cancer cell lines with Western blot analysis and in 143 primary non-small cell lung carcinomas with immunohistochemistry. Thirty-four of 143 cases (24%) stained positively. Patients with angiostatin-positive tumors survived longer (146 weeks) than patients with angiostatin-negative tumors (77 weeks; log-rank test: P = 0.07; rank-sum test: P = 0.02). To determine whether combining stimulating and inhibiting factors might improve the prognostic capability, both angiostatin and vascular endothelial growth factor (VEGF) were analyzed together with respect to patient survival. The median survival time of patients with angiostatin-positive/VEGF-negative carcinomas was 184 weeks, whereas the median survival time of patients with angiostatin-negative/VEGF-positive tumors was only 52 weeks. The angiostatin-positive tumors exhibited an increased incidence of apoptosis and a reduced capability to be transplanted into nude mice, but these differences did not reach or were only of borderline statistical significance.

A community-based assessment of heat-related morbidity in North Philadelphia

A 6-month community-based study designed to (1) determine the perceptions and barriers affecting the overall quality of life of isolated older adults greater than 65 years of age, (2) assess their risk factors, health attitudes, and beliefs concerning their susceptibility to heat-related conditions, and (3) evaluate the effectiveness of an age-specific innovative intervention program consisting of a specially marked clock-like thermometer and other creative educational materials was conducted among 34 participants during the spring and summer of 1997 in north Philadelphia. The study objectives were measured at preintervention (baseline) and at 8 weeks postintervention follow-up using a 24-item pretest/posttest self-administered questionnaire. We report the short-term benefit of our intervention, theorize that innovative strategies targeting at-risk older adults should be culturally sensitive and age-specifically appropriate, and recommend that more vigorous research methods should be implemented to lend credence to our findings.

Association of telomerase expression with successful heterotransplantation of lung cancer

This study analyzed whether the expression of telomerase may serve as prognostic factor for the aggressiveness of human non-small cell lung carcinomas. To this purpose the expression of telomerase measured by immunohistochemistry was compared with the take rate of the primary tumors that were heterotransplanted into nude mice. Formalin-fixed, paraffin-embedded specimens of 97 non-small cell lung carcinomas from primarily untreated patients were analyzed for the expression of telomerase by a goat polyclonal antibody (clone C-20). Moderate or strong telomerase-staining was found in 78 (80%) cases. Age, gender, stage and histology had no influence on the telomerase expression. It was discovered that of the 19 telomerase-negative carcinomas only five (26%) exhibited growth in nude mice while of the 78 telomerase-positive cases 37 (47%) were successfully transplanted. To confirm these results, alcohol-fixed, paraffin-embedded cancer specimens from another group of patients (n=58) were analyzed for telomerase expression by a rabbit polyclonal antibody (clone H-231). Corresponding results were obtained. The take rate of telomerase-negative carcinomas was only 36%; the take rate of telomerase-positive carcinomas was 59%. These data suggest that high telomerase expression does indeed correlate with the aggressiveness of non-small cell lung carcinomas.

Glucose-related protein (GRP78) and its relationship to the drug-resistance proteins P170, GST-pi, LRP56 and angiogenesis in non-small cell lung carcinomas

Several studies have documented that induction of the glucose-related protein (GRP78) is associated with the development of drug-resistance to antitumor drugs. However, nothing has been reported concerning GRP78 in human lung tumors and its relationship to several resistance proteins and angiogenesis. Therefore, this study analyzed the expression of GRP78 in a series of 62 consecutive lung cancer patients and examined whether or not a relationship exists between GRP78, several resistance proteins and microvessel density (MVD). Secondary, it evaluated the relationship of GRP78, LRP56 and GST-pi in cancer cell lines under hypoxic conditions and in sensitive and resistant cell lines. We determined that a relationship exists between GRP78 and the resistance proteins P170, LRP56 and GST-pi in human lung cancer. Furthermore, we observed an up-regulation of GRP78 in the resistant cell lines LUTC-ML54, OAW-Dox and OAW-Tax, but not in sensitive cell lines. Abnormal vascularization of malignant tumors is associated with the development of hypoxic regions. In hypoxic regions, several proteins, including drug resistance proteins, are expressed in greater quantities. Our study detected an inverse correlation between GRP78 and MVD. Carcinomas with low MVD exhibited a higher expression of GRP78. Furthermore, protein expression of GRP78, GST-pi and LRP56 increased in the cell lines A-549, RPMI-2650 and SC-MES-1 under hypoxic conditions. These observations suggest that hypoxia, tumor vascularization and the simultaneous expression of many resistance-related proteins, including GRP78, may play an important role in drug response and therapeutic effectiveness.

Pathophysiologic basis of contrast enhancement in breast tumors

While the diagnostic benefits of gadolinium (Gd)-chelate contrast agents are firmly established in magnetic resonance imaging (MRI) of tumors, the pathophysiologic basis of the enhancement observed and its histopathologic correlate remained vague. Tumor angiogenesis is fundamental for growth and metastasis and also of interest in new therapeutic concepts. By correlative analysis of a) histology; b) vascular density (CD31); and c) vascular permeability (vascular permeability factor/vascular endothelial growth factor [VPF/VEGF]), we found a) significantly (P < 0.001) faster exchange rates in malignant compared with benign breast lesions; b) distinct differences in enhancement characteristics between the histologic types (invasive ductal carcinoma, invasive lobular carcinoma, and ductal carcinoma in situ); and c) dependence of enhancement kinetics on the VPF/VEGF expression. The pathophysiologic basis for the differences in contrast enhancement patterns of tumors detectable by MRI is mainly due to vascular permeability, which leads to more characteristic differences than vascular density. MRI is able to subclassify malignant breast tumors due to their different angiogenetic properties.

Biological characterization of subgroups of squamous cell lung carcinomas

Recently, Pezzella et al. (Am. J. Pathol., 1997, 151: 1417-1423, 1997) reported on a subgroup of non-small cell lung carcinomas that had no morphological evidence of neoangiogenesis but appeared to grow and were highly aggressive. In this investigation, we subdivided 87 squamous cell lung carcinomas into four subgroups according to angiogenesis (low and high vessel density) and tumor growth (low and high tumor cell proliferation). The aim was to find differences, if any, in the angiogenic status and clinical behavior between these subgroups. We identified a group of tumors with low angiogenesis and high tumor cell proliferation that was characterized by high expression of vascular endothelial growth factor, low expression of basic fibroblast growth factor, reduced apoptosis, increased incidence of metastases, and short survival times. These data show that even squamous cell lung carcinomas are a heterogeneous group of tumors that can be subdivided in tumors with different biological properties and different clinical behaviors.

Inverse correlation between apoptotic (Fas ligand, caspase-3) and angiogenic factors (VEGF, microvessel density) in squamous cell lung carcinomas

In order to explore whether apoptosis is associated with angiogenesis in lung cancer, immunohistochemistry was employed to determine the pro-apoptotic factors Fas ligand (FasL) and caspase-3 (Cas-3) in 70 squamous cell lung carcinomas. Furthermore, the vascular endothelial growth factor (VEGF) and the microvessel density (MVD) were analyzed. The comparison between MVD and the pro-apoptotic factors demonstrated that the apoptotic factors are inversely related to MVD (Cas-3: p = 0.011, FasL: not significant). In order to confirm this result, FasL and Cas-3 were also compared with the expression of VEGF. Again, an inverse correlation between VEGF and the pro-apoptotic factors was found (Cas-3: p = 0.019, FasL: p = 0.008). The inverse correlation between angiogenesis and apoptosis may be explained by the activation of pro-apoptotic and anti-angiogenic factors caused by hypoxia.

Xenotransplantability of human squamous cell lung cancer in nude mice is not affected by angiogenic factors

Sixty-two human squamous cell lung carcinomas were analyzed for expression of various angiogenic growth factors and their receptors using immunohistochemistry. The data were correlated with xenotransplantability of these tumors in nude mice. None of the factors investigated did show an association with xenotransplantability. However, there was a trend that specimens lacking VEGF165 were established as xenografts at a higher incidence (52%) than those expressing VEGF165 (39%).

Relationship of urokinase and urokinase receptor in non-small cell lung cancer to proliferation, angiogenesis, metastasis and patient survival

The purpose of the analysis was to ascertain whether the expression of components of the plasminogen activation system possesses an association with several biological parameters. The expression of urokinase (uPA) and urokinase receptor (uPAR) was analyzed in 137 non-small cell lung carcinomas by immunohistochemistry. No relationship could be observed between the proliferative activity of the carcinomas measured by flow cytometry and the expressions of uPA and uPAR. In addition, there was no association of the expressions of uPA or uPAR and vessel density (angiogenesis), neither any significant correlation between the expressions of uPA or uPAR and metastasis. The median survival was shorter for patients with uPA positive carcinomas than for those with uPA negative tumors (60 vs. 111 weeks; p=0.018). The relative risk estimate for patients with uPA positive tumors was increased by a factor of 1.8. In contrast, the expression of uPAR showed no significant correlation with overall survival.

Angiogenesis and cigarette smoking in squamous cell lung carcinomas: an immunohistochemical study of 28 cases

Angiogenesis in tumors is influenced by several factors which in turn are associated with chemoresistance or radioresistance. Moreover, the tumors of smokers are known to be relatively resistant to chemotherapy. This investigation attempts to determine whether or not a relationship exists between cigarette smoking and angiogenesis in lung cancer. Tumor samples from 14 non-smokers and 14 heavy cigarette smokers were selected for this study. The populations were matched for age, sex and tumor stage. Resistance to doxorubicin, microvessel density, the expression of vascular endothelial growth factor (VEGF) and thrombospondin (TSP) were analyzed in both populations. Tumors of smokers were more frequently resistant to doxorubicin in vitro, had lower vessel counts and a reduced expression of VEGF compared to tumors of nonsmokers. In contrast, TSP was significantly increased in the tumors of smokers. These data show that angiogenesis in lung tumors is linked to a patient's smoking habits.

PD-ECGF, bFGF, and VEGF expression in non-small cell lung carcinomas and their association with lymph node metastasis

The angiogenic factors PD-ECGF, bFGF and VEGF were determined immunohistochemically in 168 non-small cell lung carcinomas to investigate whether the expression of these parameters is correlated with lymph node metastasis of patients. The expressions of the above mentioned factors was indeed associated with lymph node metastasis, but the results were not statistically significant. However, a combination of the factors PD-ECGF, bFGF and VEGF significantly improved the prognostic information. The number of tumors with lymph node involvement increased with the number of angiogenic factors. Only 43% of the patients had-lymph node involvement when all factors were negative whereas 77% showed metastasis when all factors were positive (one factor positive: 53%, two factors positive: 68). This result is statistically significant (p = 0.002, test for trend).

Expression of platelet-derived endothelial cell growth factor in non-small cell lung carcinomas: relationship to various biological factors

The expression of platelet-derived endothelial cell growth factor (PD-ECGF) was determined immunohistochemically in 143 non-small cell lung carcinomas. Staining was observed in 48% of the cases. A relationship between histology, stage, erbB-1, erbB-2, ras and PD-ECGF expression was not found. A relationship of borderline significance was observed between PD-ECGF and p53 expression. There was also no relationship between PD-ECGF expression and proliferative activity (G1 phases, S phases, cyclin A). In contrast, a correlation between PD-ECGF- and VEGF-expression was detectable (p=0.009). Furthermore, PD-ECGF expression was related to the response of lung carcinomas to doxorubicin (p=0.0004). Of 35 sensitive tumors, 26 carcinomas were PD-ECGF-positive (74%) while of 108 resistant carcinomas only 43 tumors (40%) exhibited PD-ECGF expression.

Association between nm23-H1 expression, proliferation and apoptosis in non-small cell lung carcinomas

Twelve non-small cell lung carcinomas and adjacent normal lung tissues were examined for mutations of the nm23-H1 gene by using SSCP analysis and for an expression of the nm23-H1 protein by immunohistochemistry. No mutations could be found in either the carcinomas or in the adjacent normal tissues. In contrast, six of 12 carcinomas showed protein expression while only one adjacent normal lung tissue yielded a positive staining result. Therefore, the expression of nm23-H1 protein was analysed in a larger group of non-small cell lung carcinomas (n = 185) to determine whether or not the expression of nm23 protein may be of prognostic relevance. Only a weak relationship between nm23-H1 expression and lymph node involvement was observed. However, a significant correlation between proliferation and nm23-H1 expression was detected. Additionally, a direct correlation between apoptosis and nm23-H1 expression or between myc and nm23-H1 expression was found. Finally, non-small cell lung carcinomas that expressed nm23-H1 protein were more frequently sensitive to doxorubicin than carcinomas that did not express this protein.

O6-methylguanine-DNA methyltransferase activity and sensitivity to cyclophosphamide and cisplatin in human lung tumor xenografts

The DNA repair protein O6-methylguanine-DNA methyl-transferase (MGMT) is a main determinant of resistance of cells to the cytostatic effects of O6-alkylguanine-generating alkylating agents. The purpose of our study was to assay MGMT activity in cells of lung cancers and to correlate MGMT levels with chemotherapy response to cyclophosphamide (CTX) and cisplatin (DDP). MGMT levels were determined in 14 human lung tumor xenografts. There was a wide variation of MGMT expression in these tumors, ranging from 10 to 984 fmol/mg protein. There was also a wide range in the sensitivity of the xenografts to CTX and DDP, as measured by specific growth delay. When the MGMT levels of the different xenograft lines were compared with the corresponding responses to CTX and DDP, a close correlation was found between MGMT activity and CTX (lin reg., r = -0.83, p < 0.05). The higher the MGMT activity, the less pronounced was the growth-inhibiting effect of CTX. With DDP, no such correlation was found. Our results indicate that the in vivo response of tumors to CTX is related to the level of MGMT expression.

Smoking-related increase of O6-methylguanine-DNA methyltransferase expression in human lung carcinomas

Eighty-three non-small cell lung carcinomas (NSCLC) of previously untreated patients were analysed for expression of O6-methylguanine-DNA methyltransferase (MGMT) by means of immunohistochemistry. Expression of MGMT was detected in 62 of 83 tumours (75%). There was a significant difference in MGMT staining between smokers and non-smokers (P = 0.001). Tumours of smokers expressed more frequently MGMT than tumours of non-smokers. There was a trend of MGMT expression to be higher in tumours of patients smoking >20 cigarettes/day than patients smoking <20 cigarettes/day. Abstinence from smoking resulted in a significant decrease in MGMT expression (lin reg r = -0.59, P < 0.05). These results demonstrate that MGMT expression in human lung carcinomas is influenced by smoking habits of the patients.