Comparison of daunorubicin and Fluo-3 for detection of multidrug resistance in human tumor cells

The detection of multidrug resistance (MDR) in clinical samples is still a topic for discussion. One method, proven extremely useful for detection of membrane proteins in patients with hematological malignancies is the flow cytometrical analysis of individual tumor cells. Recently an assay was described based on the labeling of the P-glycoprotein (P-gp) with the monoclonal antibody MRK16, combined with detection of active daunorubicin (DNR) extrusion. In order to improve the specificity of the assay, on line with the results obtained by Wall et al., we exploited staining with Fluo-3. Both assays prove to be able to discriminate between drug-resistant and drug-sensitive cells. A major drawback of labeling with Fluo-3 in combination with the monoclonal antibody MRK16 is the important overlap of emission spectra of both fluorochromes. Moreover, using Fluo-3 for the detection of MDR might be complicated by the fact that differences in fluorescence intensities are not solely dependent on the presence of P-gp, but also on the activity of cytosolic esterases and the intracellular calcium concentration. Combination of the detection of structural and functional aspects of the MDR-associated protein may lead to a more precise detection of the MDR-positive patient.

Phase IB study of doxorubicin in combination with the multidrug resistance reversing agent S9788 in advanced colorectal and renal cell cancer

S9788 is a new triazineaminopiperidine derivate capable of reversing multidrug resistance (MDR) in cells resistant to chemotherapeutic agents such as doxorubicin. It does not belong to a known class of MDR revertants, but its action involves the binding of P-glycoprotein. Thirty-eight evaluable patients with advanced colorectal or renal cell cancer were treated with doxorubicin alone (16 patients) followed after disease progression with combination treatment of doxorubicin plus S9788 (12 patients) or upfront with the combination of doxorubicin plus S9788 (22 patients). S9788 was given i.v. as a loading dose of 56 mg m-2 over 30 min followed by doxorubicin given at 50 mg m-2 as a bolus infusion. Thereafter, a 2-h infusion of S9788 was administered at escalating doses ranging from 24 to 120 mg m-2 in subsequent cohorts of 4-10 patients. Pharmacokinetic analysis demonstrated that concentrations of S9788 that are known to reverse MDR in vitro were achieved in patients at non-toxic doses. Compared with treatment with doxorubicin alone, treatment with the combination of doxorubicin and S9788 produced a significant increase in the occurrence of WHO grade 3-4 granulocytopenia. Treatment with S9788 was cardiotoxic as it caused a dose-dependent and reversible increase in corrected QT intervals as well as clinically non-significant arrhythmias on 24- or 48-h Holter recordings. Although clinically relevant cardiac toxicities did not occur, the study was terminated as higher doses of S9788 may increase the risk of severe cardiac arrhythmias. Twenty-nine patients treated with S9788 plus doxorubicin were evaluable for response, and one patient, who progressed after treatment with doxorubicin alone, achieved a partial response. We conclude that S9788 administered at the doses and schedule used in this study results in relevant plasma concentrations in humans and can safely be administered in combination with doxorubicin.

Elevated levels of the angiogenic cytokines basic fibroblast growth factor and vascular endothelial growth factor in sera of cancer patients

The concentration of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) was determined in the serum of 90 untreated and 42 treated metastatic cancer patients, including patients with colorectal, breast, ovarian and renal carcinomas, with an enzyme-linked immunosorbent assay (ELISA). Levels higher than the 95th percentile of the concentrations of a control group, i.e. 7.5 pg ml(-1) for bFGF and 500 pg ml(-1) for VEGF, were identified as 'elevated'. One measurement during follow-up was included into the analysis per patient. For 19 treated patients, consecutive serum samples were analysed. Fifty-seven per cent of all untreated patients had elevated serum levels of one or both angiogenic factors. The fraction of patients with elevated serum levels of bFGF and/or VEGF was similar in the different tumour types. Agreement of bFGF levels and VEGF levels, classified in relation to their respective cut-off values, was present in 67% of all patients. Fifty-eight per cent of the patients with progressive disease during treatment compared with 15% of the patients showing response to treatment (chi-squared test P < 0.05) had elevated bFGF and/or VEGF serum levels. When consecutive serum samples were analysed, two-thirds of the patients showing progressive disease had increasing serum levels of the angiogenic factors compared with less than one-tenth of the patients showing response (chi-squared test P < 0.05). The lack of association between the serum bFGF and VEGF levels and the tumour type may suggest an aspecific host reaction responsible for solid tumour-related angiogenesis. The main determinants of the serum bFGF and VEGF concentration are the progression kinetics of the metastatic carcinomas.

Influence of investigator experience and microscopic field size on microvessel density in node-negative breast carcinoma

In this study on the determination of intratumoral microvessel density (MVD) in breast cancer, we have investigated the influence of the observer experience and the microscopic field size. We have used the sample set reported on earlier in the J Natl Cancer Inst 87: 1797-1798, 1995. This case-control study has shown a positive association of high MVD and unfavorable outcome when comparing node-negative pT1-2 breast carcinoma (NNBC) patients with a disease-free period of over ten years with those with an early distant relapse. Tumor sections of both outcome groups (favorable: n = 19; unfavorable: n = 19) were immunostained for factor VIII related-antigen (FVIII r-Ag). Microvessels were counted in the areas of most intense vascularization ('hot spots'), both at magnification x 200 (field size of 0.61 square mm) and x 400 (field size of 0.15 square mm), by one inexperienced and three experienced observers. Microphotographs of individual vascular hot spots were analyzed using overlays resembling the two field sizes. The main results obtained are: i) a confirmation of the prognostic value of microvessel density in the case-control sample set (n = 38) was established by all experienced but not by the unexperienced investigator; ii) both at x 200 and x 400 magnification, angiogenesis quantification in vascular hot spots contained prognostic information. The results of this study indicate that the selection of vascular hot spots in tumor sections immunostained for an antigen expressed on endothelial cells is more prone to inter-observer variability and more dependent on training than the counting of the microvessels within predefined hot spots itself. The microscopic magnification and resulting field size do not influence the prognostic significance of MVD in NNBC. This information validates the development of more objective methods of measuring the amount of angiogenesis within malignant tissue. This will allow more accurate implementation of the angiogenesis parameter in multiparametric and prospective prognostic factor studies in NNBC.

Serum basic fibroblast growth factor and vascular endothelial growth factor and tumour growth kinetics in advanced colorectal cancer

BACKGROUND

The development of new microvessels in the surrounding stroma is a prerequisite for tumour progression. Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are angiogenic factors expressed in a broad range of human tumours. We have measured the concentrations of both cytokines in the serum of patients with advanced colorectal cancer. We questioned whether these levels are related to the number of tumour sites, the volume of liver and/or lung involvement and the growth kinetics.

PATIENTS AND METHODS

44 untreated colorectal adenocarcinoma patients who had developed metastatic and/or recurrent disease were evaluated. Serum levels of bFGF and VEGF were repeatedly measured using ELISA. The extent of target organ involvement and the kinetics of tumour volume growth were determined on consecutive computer tomography (CT) images.

RESULTS

Patients with a tumour volume doubling time of less than 6 months showed a higher bFGF and VEGF serum level than others, independent of the number of sites involved and the extent of the metastatic disease.

CONCLUSIONS

The data suggest a predictive value of serum bFGF and VEGF levels for the progression of disease in patients with untreated metastatic colorectal cancer. The results corroborate the importance of angiogenesis in the process of tumour growth. The serum levels might prove a useful tool in the quantification of angiogenesis and might be of valuable information in the decision process of initiating palliative chemotherapy. It will be of considerable importance to investigate whether the serum bFGF and VEGF levels have a predictive value on the probability of response to cytotoxic therapy.

Deep cerebral invasion by basal cell carcinoma of the scalp

We report recurrent basal cell carcinoma of the scalp with deep cerebral invasion in an 82-year-old man. Plain films and CT showed extensive, full thickness, skull destruction at the vertex. Gadolinium-enhanced MRI revealed neoplastic invasion of the meninges and left cerebral hemisphere, down to the lateral ventricle. We postulate that tumour extended into the brain along perivascular spaces of transcerebral vessels. This hypothesis is supported by the cleft-like contrast enhancement on MRI.

The influence of hypoxia on the cytotoxicity of concomitant KW-2149 and ionizing irradiation in Chinese hamster fibroblasts

7-N-((2-((2-(gamma-L-glutamylamino)ethyl)dithio)ethyl))-mitomycin C (KW-2149) is a newly synthesized water-soluble mitomycin C (MMC) analog. Preclinical testing showed an interesting activity profile and a superior hematological tolerance in murine models. The aim of this study was to investigate the interaction of this compound with ionizing radiation, both under normoxic and hypoxic conditions, in Chinese hamster fibroblasts (V79). V79 cells were irradiated both under normoxic conditions and after a 1 h period of hypoxia. Paired irradiation dose-response curves confirmed the significance of radioresistance under hypoxia with an oxygen enhancement ratio of approximately 3. In contrast to MMC, KW-2149 showed no increased cytotoxic effect on hypoxic V79 cells. The cytotoxic effect of KW-2149 increased with increasing concentration, irrespective of the ambient oxygen pressure. When KW-2149 was combined with irradiation under hypoxic conditions, cytotoxicity was significantly enhanced under these conditions. The difference in survival between normoxic and hypoxic conditions was statistically significant (p < 0.004). These data suggest a radiosensitizing effect of KW-2149, more pronounced under hypoxic conditions. This effect increases with radiation dose. It also corroborates earlier suggestions of a different mode of action of KW-2149 as compared to MMC.

Correlation of the response to cisplatin of human ovarian cancer cell lines, originating from one tumor but with different sensitivity, with the recovery of DNA adducts

Cis-Diamminedichloroplatinum(II) (CDDP) is used in the treatment of various cancers, with or without ionizing radiation. During treatment, resistance may develop, and cross-resistance can also occur. DNA is the main target for CDDP and ionizing radiation, and we therefore evaluated the correlation between the amount of CDDP-DNA adducts and the cytotoxic activity of CDDP in human ovarian cancer cell lines with different platinum sensitivities. DNA-adduct levels were investigated 18 hr after CDDP exposure in three cell lines originating from the same human ovarian cancer. The least sensitive cells appeared to have the largest amounts of CDDP-DNA adducts, while the most sensitive had higher adduct levels than the parental cells. The proportion of the four adducts measured (i.e., Pt-G, Pt-AG, Pt-GG, and G-Pt-G) was comparable in all cell lines, with a preference for Pt-GG adduct formation (> 50% of the adducts). Intracellular CDDP concentrations were higher in sensitive than in resistant cells, in contrast to the degree of CDDP adduct formation. Data obtained following continuous exposure of CDDP-resistant cells to CDDP suggest that DNA repair is partly responsible for resistance to CDDP. We conclude that the amount of CDDP-DNA adduct formation in cancer cells is not a predictor of CDDP cytotoxicity.

Correlation of intratumoral microvessel density and p53 protein overexpression in human colorectal adenocarcinoma

A malignant cell population needs the development of microvessels in order to grow and metastasize. Recently, a role for the p53 gene in the regulation of this angiogenic process has been suggested. Wild-type p53 is involved in the secretion of Trombospondin-1 (TSP-1), an angiogenesis inhibitor. Mutations of the p53 gene cause a downregulation of TSP-1 mRNA in cell lines. Mutant p53 also upregulates the expression of vascular endothelial cell growth factor, a potent angiogenic factor. Together with the reported association of p53 protein overexpression and microvessel density (MVD) in head-and-neck squamous-cell carcinoma, these in vitro findings led us to investigate whether this association would also apply in colorectal adenocarcinomas. Structural changes of the p53 gene are the most frequent observed mutations in colorectal carcinoma and are suspected to be involved in the carcinogenesis at a relatively early stage. Parallel tissue sections from primary colorectal adenocarcinomas were immunostained for CD31, an endothelial cell marker, and with DO7, recognizing both mutant and wild-type p53 protein overexpression. The presence of p53 protein overexpression was found to be significantly associated with high MVD in the vascular hot spots. Our results are in accordance with the in vitro studies on the involvement of p53 in angiogenesis. Mutant p53 might stimulate tumor angiogenesis both indirectly, by augmenting the tumor cell proliferation, and directly, by upregulating angiogenic factors and downregulating angiogenic inhibitors.

Partitioning of ifosfamide and its metabolites between red blood cells and plasma

A recently developed GC-MS analytical method for the quantitative determination of oxazaphosphorines and their metabolites in blood plasma, using stable trifluoroacetyl derivatives and electron capture negative chemical ionization detection, was applied to measure the partitioning of the antitumor drug ifosfamide and its metabolites between plasma and red blood cells for four cancer patients. The separation of a constant volume of red blood cells was performed using a special instrument, MESED, through centrifugation of blood samples. The measured compounds were ifosfamide, 2- and 3-dechloroethylifosfamide, 4-ketoifosfamide, carboxyifosfamide, ifosfamide mustard, 2-chloroethylamine and 1,3-oxazolidin-2-one. Concentration-time profiles for the metabolites in the two blood fractions and partitioning factors between erythrocytes and plasma were obtained. For ifosfamide itself, and metabolites with an intact ring system, a partitioning factor between 1 and 2 was observed for the concentration ratio between red blood cells and plasma in the patients studied. However, for the compounds with an open structure, carboxyifosfamide and ifosfamide mustard, partitioning factors higher than 3 were obtained. The active antitumor metabolite ifosfamide mustard showed a strong preference for the red blood cells in the measured patient samples. This means that erythrocytes may play an important role in the transport and the subsequent release of the active alkylating agent to the tumor cells.

Long-term results of continuous treatment with recombinant interferon-alpha in patients with metastatic carcinoid tumors--an antiangiogenic effect?

This study investigated the efficacy of long-term continuous and dose-escalated interferon-alpha (IFN) treatment in patients with progressive carcinoid tumors. In this single-institution, phase II study 16 chemotherapy-naive, eligible patients were entered. Interferon treatment consisted on 5 MIU IFN three times weekly s.c. until radiologic progression. In case of progression the dose was increased to 10 MIU. Radiologic and biochemical evaluation was done monthly and thereafter 3 monthly. We have treated 16 patients of whom 15 are evaluable for tumor response. Calculated by standard response criteria, three patients experienced a partial response. Another three had an important minor response. Median response duration was 24 months (range 18-51 months). Biochemical responses were observed in nine out of 12 patients with an elevated 5-hydroxyindoleacetic acid excretion. The serum neuron-specific enolase proved a reliable marker for both response and progression. In the one patient progressive after 3 months, a dose increment to 10 MIU was without effect. In patients initially not progressing or responding to 5 MIU, escalation to 10 MIU had a short lasting beneficial effect in three cases. The radiological characteristics and the kinetics of these responses are compatible with an anti-angiogenic effect of IFN. This study of IFN in carcinoid tumors confirms the activity in this disease. Our results demonstrate the necessity of initiating treatment only in radiologically progressive patients and continuing this treatment until progression. We feel that currently the activity of IFN in metastatic carcinoid tumors compares favorably with that of systemic chemotherapy in patients with progressive disease.

Sternal resection for primary presternal and retrosternal mediastinal liposarcoma

In a 34-year-old patient, sternal resection was necessary for complete removal of a primary mediastinal myxoid liposarcoma grade I, which had grown around the right sternal border. Reconstruction was by the methylmethacrylate sandwich technique. Five months postoperatively part of the device had to be removed due to persistent inflammation. Two years after the initial operation there is no evidence of local recurrence or distant metastases.

[In vitro effects of piracetam on the radiosensitivity of hypoxic cells (adaptation of MTT assay to hypoxic conditions)]

This paper describes the adaptation of the MTT assay to hypoxic conditions in order to test the in vitro effect of piracetam on hypoxic cells and particularly on the radiosensitivity of hypoxic cells since this drug has shown clinical effect on acute and chronic hypoxia. The V79 cell line was selected by reference to preliminary hypoxic experiments using clonogenic assay and euoxic experiments using clonogenic and MTT assays. Cell growth and survival in our hypoxic conditions were assessed using MTT assay with an enclosure and special 48-well plates both made of glass. Growth curves on glass versus reference polystyrene plates were comparable and confirm the validity of using special glass plates. Growth curves on glass plates after 1-hour exposure to nitrogen versus air were comparable, so there is no bias effect due to gas composition. Survival curves using MTT versus reference clonogenic assay were comparable after radiation exposure in eu- and hypoxic conditions, and confirm the validity of our original technique for creating hypoxia. The Oxygen Enhancement Ratio was of about 3 for 1-hour hypoxic exposure. Piracetam gave no cytotoxic effect up to 10 mM of piracetam. Growth curves after continuous drug exposure and 1-hour euoxic versus hypoxic exposure gave no cytotoxic effect up to 10 mM of piracetam. Survival curves after continuous drug exposure to 10 mM of piracetam gave no significant effect on the radiosensitivity of hypoxic V79 cells using MTT or clonogenic assay. However, this does not preclude a potential in vivo effect of piracetam on the radiosensitivity owing to its action on microcirculation and its rheologic properties. The adaptation of the MTT assay to hypoxic irradiation conditions yields the easy screening of radiosensitizing drugs: shorter incubation, semi-automatic method and simultaneous analysis with different serial concentrations thanks to the special 48-well glass plates.

Diagnosis and treatment of soft tissue sarcomas in adults

The optimal treatment of soft tissue sarcoma remains a challenge for the multidisciplinary approach in modern oncology. Only when a team of experienced clinicians, oncologists, radiotherapists, and oncologic orthopedic surgeons cooperates with the radiologist and the pathologist can optimal treatment be guaranteed. Recent advances in our knowledge of sarcomas have resulted from more detailed analysis of the cytogenetic and molecular changes in the different types of sarcoma. The prognostic significance of many biologic markers is still the subject of ongoing investigations, with sometimes conflicting results. The usefulness of adjuvant radiotherapy in the combined approach for optimal local control of both extremity and trunk sarcomas is confirmed in different studies. the discovery of antitumor activity of taxoids in this disease brings new chemotherapeutic combinations within reach.

Effects and systemic uptake of the new mitomycin C analogue KW-2149 in beagle dogs after intravesical administration

The present study was designed to evaluate the local effects of the new mitomycin C analogue KW-2149 after intravesical instillation, together with its penetration into the systemic circulation in healthy beagle dogs. Two reference dogs were treated with two instillations of mitomycin C (30 mg in 30 ml phosphate buffer). Four dogs were given two, three, four and six instillations, respectively, of KW-2149 (60 mg in 30 ml phosphate buffer). KW-2149 concentrations measured in the systemic circulation were very low and were frequently found to be below the limit of determination. The number of instillations had no influence on the KW-2149 concentrations measured in the systemic circulation. Blood analysis showed no systemic toxicity. The histopathological findings in the bladder were comparable in both groups. The number of instillations had no influence on the severity of the lesions found in the bladder wall. On the basis of its in vitro activity KW-2149 can be regarded as a promising agent for intravesical treatment of superficial bladder cancer.

Microvessel quantification in primary colorectal carcinoma: an immunohistochemical study

The vascularisation of human primary colorectal carcinomas was studied immunohistochemically using the endothelial cell markers CD31 and factor VIII-related antigen. Tumour sections were systematically scanned at a magnification of x 100 to find areas of intense neovascularisation. Microvessel counts within these vascular 'hotspots' were performed at magnification x 250. Regions in which tumour cords were surrounded by a collagen IV-positive basement membrane were compared with those in which this was absent and with normal mucosa. CD31 appeared to be a more sensitive marker for endothelial cells than factor VIII-related antigen (mean 185 +/- 59 and 120 +/- 38 microvessels mm-2). Within individual tumour sections microvessel counts in vascular hotspots with highest vessel density correlated significantly with microvessel counts in vascular hotspots with second highest vessel density (P < 0.01). Microvessel counts in tumour areas where collagen IV-positive basement membrane were absent exceeded those in areas where it was present (factor of 1.7) and those in normal mucosa (factor of 1.6). The differences in vessel density between individual tumours and the low variability in vessel density within individual tumours using this quantification technique allow us to investigate the prognostic value of vessel density in areas of intense neovascularisation in human primary colorectal carcinomas.

Cryptorchidism and extragonadal germ cell tumor

A patient with an extragonadal germ cell tumor and a history of bilateral cryptorchidism is reported. The rarity of this concurrence in a single patient is discussed. The necessity for thorough investigation of the cryptorchid testes in patients with metastatic germ cell cancer remains essential.

Microvessel density, endothelial cell proliferation and tumour cell proliferation in human colorectal adenocarcinomas

BACKGROUND

Thymidine incorporation studies performed in animal tumour models, revealed major differences in endothelial cell proliferation when tumour tissue was compared with normal tissue. The fraction of proliferating endothelial cells is reported to be increased by a factor of 30 to 40 in tumour tissue.

PATIENTS AND METHODS

To make it possible to analyze the endothelial cell proliferation in human tumours, an immunohistochemical double staining technique comprising CD31, an endothelial cell marker, and Ki-67, a proliferation marker, was developed. Endothelial cell proliferation was analysed in 21 primary human colorectal adenocarcinomas and in the adjacent mucosa.

RESULTS

Proliferating endothelial cells were found throughout the entire carcinoma. The mean overall endothelial cell labeling index (ECLI) was 9.9% (range, 5.4-18.0), and the labeling index of endothelial cells in areas of intense neovascularisation was even higher. Mean ECLI in the vascular hot spots was 21.0% (range, 6.8-35.0), and the mean tumour cell labeling index (TCLI) in the maximally Ki-67 immunostained areas was 78.3% (range 47.0-89.7). In 14 of 21 carcinomas, these areas were predominantly found at the luminal margin of the tumour, as were the vascular hot spots. A significant positive correlation was found between tumour vascularity, measured in the vascular hot spots, and tumour cell proliferation, measured in the maximally Ki-67 immunostained areas (p < 0.05). To analyse this relation in more detail, microvessel density (MVD), TCLI and ECLI were determined per x400 microscopic field by scanning in sequence from the luminal tumour margin to the invasive tumour base. In all tumours, the pattern of the MVD per x400 field, from the luminal margin to the tumour base, was similar to that of the TCLI and ECLI.

CONCLUSIONS

These findings confirm that the fraction of cycling endothelial cells is higher in human colorectal carcinoma than in the adjacent mucosa which suggests that endothelial cells are proliferating in most of the individual capillaries in tumour tissue. Regional differences in MVD correlate with differences in tumour cell proliferation in these tumours.

Diagnosis and treatment of soft tissue sarcomas in adults

Our knowledge of the molecular biology of sarcomas has progressed considerably over the past year, with major emphasis on the role of p53 and MDM2 gene mutations. Further studies on drug resistance mechanisms and the role of MDR1 expression in sarcomas have been reported. The investigations using different imaging techniques as ways of predicting tumor necrosis more accurately than our current response measurements after therapy have led to promising results. The many clinical phase II studies with new drugs led to the identification of taxotere as a new active agent against soft tissue sarcomas. Similar impressive results, such as those obtained with isolated limb perfusion in melanoma, have been reported in limb sarcomas with an identical regimen. The activity of ifosfamide in pretreated patients, administered at an increased dose, is suggestive of dose dependency. The improved results in phase II studies of dose-intensive chemotherapy with the support of colony-stimulating factors are encouraging and these regimens are now being investigated in the adjuvant setting.