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Background: It is believed that chemotherapy (ChT) is ineffective in follicular thyroid carcinoma (FTC) and Hürthle cell thyroid carcinoma (HCTC). The aim of our retrospective study was to find out whether neodjuvant ChT before thyroid surgery had any effect on the size of primary tumor in patients with FTC or HCTC., Methods: The study included 29 patients (20 women, 9 men; mean age: 60.8 years) with FTC or HCTC who had T3 or T4 tumor and were treated with neoadjuvant ChT from 1979 to 2004. A mean tumor diameter was 9.3 cm. Extrathyroid growth of tumor was present in 15 patients. Regional and distant metastases were detected in 6 and 12 patients, respectively. With respect to the site of metastatic spread, the lung was involved in eight patients and the skeleton in five. ChT consisted of vinblastine in 19 cases, vinblastine with adriamycin in 5 cases, or other ChT regimens in 5 cases., Results: Altogether, 67 cycles of ChT were given and tumor size decreased by >50% in 13 patients (=45%). ChT was effective in patients with FTC and HCTC in 47% and 43%, respectively. In the patients with and without distant metastases, the primary tumor size decreased by >50% in 17% and 65% (p=0.02), respectively. R0, R1, and R2 resection was performed in 15, 10, and 4 cases, respectively. Histopathology revealed that ChT (i.e., wide areas of tumor necrosis) was effective in seven patients (24%). The 5- and 10-year cause-specific survivals of the patients were 77% and 47%, while the 5- and 10-year disease-free intervals were 57% and 46%, respectively. Six patients are alive (median survival: 162 months), four of them have no evidence of disease, six patients died of other causes (median survival: 101 months), while 17 patients died of FTC or HCTC (median survival: 72 months). Among them, 16 died of distant metastases, while only one succumbed to locoregional recurrence and distant metastases., Conclusions: ChT before surgical procedure may be effective in order to decrease the tumor size in FTC or HCTC in 45% of patients.

Information on the in vivo antitumor efficiency of the combination of Vinca alkaloids in animal tumor models, especially vinblastine (VLB) with cisplatin [cis-diamminedichloroplatinum(II); CDDP] is very limited. Therefore, the aim of our study was to explore whether antitumor schedule dependence exists for the combination of CDDP and VLB on i.p. Ehrlich ascites tumors in mice. Animals were treated 3 days after tumor transplantation with VLB (0.006 mg/kg) or CDDP (0.05 mg/kg) alone, VLB followed by CDDP, and CDDP followed by VLB. The time interval between i.p. injections of the drugs was 24 h. Cell number was measured by counting viable cells using the trypan blue exclusion assay, cell platinum content by electrothermal atomic absorption spectrometry, DNA distribution pattern using flow cytometry, apoptosis by flow-cytometric terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and cell morphology. Combination of CDDP and VLB resulted in additive interaction when VLB preceded CDDP as determined from cell survival data 24 h after completion of the therapy and in increased platinum content (two times) compared with the same combination in a reverse schedule (CDDP given before VLB), which resulted in antagonism. None of the treatment combinations induced apoptosis. We propose that the observed increase in antitumor effectiveness is mainly due to higher platinum accumulation in tumor cells, which we unambiguously demonstrated by measurement of platinum content in the tumor cells, leading to increased cytotoxicity as well as to cell cycle-dependent effects of VLB and CDDP.

Vinblastine (VLB) previously has been shown to perturb tumor blood flow, but the effect of these perturbations on tissue oxygenation is not known. The recent development of electron paramagnetic resonance (EPR) oximetry now has made it feasible to measure the effects of changes of perfusion on the pO(2) in tumors and normal tissues as a function of time and dose. We measured changes in tumor perfusion by Patent blue staining, tumor blood volume and microvascular permeability by contrast-enhanced magnetic resonance imaging, and tumor oxygenation by EPR in s.c. SA-1 murine tumors. We found that treatment with VLB induced dose-dependent reduction in tumor perfusion. One hour after i.p. treatment of mice with 2.5 mg/kg VLB, tumor perfusion was reduced to 20% of the pretreatment value and returned to close to original values within 48 h. A transient tumor blood flow-modifying effect of VLB was demonstrated also by contrast-enhanced magnetic resonance imaging; reduction of tumor blood volume and microvascular permeability was found. Reduced tumor oxygenation was found as measured by EPR oximetry, with the same time course of changes in tumor blood flow. Tumor oxygenation was reduced to 50% of pretreatment value 1 h after the treatment with 2.5 mg/kg VLB and returned to pretreatment levels within 24 h after the treatment. Although the directions of the changes in perfusion and oxygenation were similar, they were quantitatively different. Reduction in oxygenation of normal tissues, muscle, and subcutis also occurred but was smaller and returned to pretreatment values more quickly compared to the changes induced in the tumors. In conclusion, the present study demonstrates that VLB causes a profound reduction in tumor blood flow and oxygenation, which may have implications in controlling side effects of therapy and the planning of combined treatment with VLB, either with other chemotherapeutic drugs or with radiotherapy.

The electron paramagnetic resonance method (EPR) was used to study the effects of vinblastine (VLB) on cell membrane fluidity in wild-type HeLa cells (HeLa K) and its subclone, which is resistant to several drugs (HeLa CA). HeLa CA cells, obtained by treatment of HeLa K with CDDP, were found to be more resistant to VLB than to CDDP. The experimentally observed EPR spectra were correlated with the calculated spectra obtained by computer simulation. The results indicate that the cell membrane of HeLa K and HeLa CA cells is heterogeneous and can be described with at least three types of coexisting domains with different fluidity characteristics. The two more fluid domains of HeLa CA cells were found to be more fluid than in HeLa K cells. The fluidity of the less fluid domain remained unchanged but its portion in the membrane was increased. VLB treatment did not affect the membrane fluidity of HeLa CA cells significantly. On the other hand, 1 h of treatment of HeLa K cells with 1 ng/ml VLB did not change the fluidity characteristics of membrane domains but decreased the portion of the less fluid domains. This was also reflected in an average increase of the entire membrane fluidity. The observed changes were detected at VLB concentrations which were far below the cytotoxic level.

Vinblastine (VELBE) is one of the first chemotherapeutic agents used in the treatment of malignancies. To explore the effectiveness of various treatment regimens, bolus versus 24-hour continuous VELBE treatment was tested on an EAT tumor model in mice. Continuous VELBE infusion was simulated by splitting the bolus VELBE dose into 4 fractions, injected at 8-hour intervals. A comparison of antitumor effectiveness between bolus and split dose VELBE treatment was determined by three assays: cell survival, tumor growth delay and animal survival. The cell survival curves of both bolus and split dose VELBE treatments indicated a biphasic response with an initial fast reduction in cell survival followed by a plateau. However, split dose treatment was significantly more effective than bolus treatment at all doses tested (p < 0.001). Tumor growth delay of the split dose VELBE treatment was 6.9 days and of the bolus VELBE treatment 3.0 days, indicating that the split dose treatment is approximately 2-times more effective (p < 0.001). Median survival time of mice treated with split VELBE dose (24.0 days) was significantly longer compared to that of mice treated with bolus VELBE dose (16.5 days) (p < 0.001). The median survival time of control untreated mice (16.0 days) and bolus treated mice did not differ (p = 0.24). Our study shows that at the same VELBE dose the split dose VELBE treatment is more effective than VELBE administered in bolus.

Cell membranes can be targets of some anti-cancer drugs. Therefore, the purpose of this study was to determine whether vinblastine (VLB) can also affect the tumor cell membrane. On the in vivo SA-1 tumor model, alteration of cell membrane fluidity (measured by electron paramagnetic resonance, EPR), cytotoxicity and morphological changes of the SA-1 tumor cells after VLB treatment were studied. The cytotoxic effect of VLB was biphasic, with an initial fast increase in cytotoxicity followed by a plateau. The surviving cells had increased membrane fluidity and were morphologically changed. The dose-response curve of VLB on membrane fluidity was also biphasic with an initial fast increase in membrane fluidity followed by a plateau. Since dose-response curves of VLB cytotoxicity and its effect on membrane fluidity were similar, there was a high correlation between both effects. The effect of VLB on membrane fluidity was the most pronounced at 24 h and 48 h after treatment. The results of this study indicate that VLB affects cell membrane by increasing the membrane fluidity of SA-1 tumor cells in vivo in a dose-and time-dependent manner. Therefore, this finding may be beneficially implemented also in priming cells for other cytotoxic drugs and for appropriate timing of drug sequence in combined schedules.

In this study, we tried to define in vitro interactions of two antitumor agents that have different sites and different mechanisms of action. Vinblastine (VLB) in combination with human recombinant interferon-alpha A/D (rHuIFN-alpha A/D) and in combination with murine recombinant interferon-gamma (rMuIFN-gamma) was studied. The effect of the combination was determined with cell growth kinetics assay on B-16 melanoma and the interaction defined by means of Spector's formula. Both the combination of rHuIFN-alpha A/D with VLB and the combination of rMuIFN-gamma with VLB synergistically inhibited cell growth in vitro. There was a positive biochemical modulation between the two drugs, but it is still unknown whether it occurred at the level of uptake into the cell, metabolism within the cell or egress from the cell.

The influence of vinblastine (VLB) in combined chemotherapy on tumor cell membrane fluidity of a patient with exulcerated soft tissue sarcoma was studied by the electron paramagnetic resonance method (EPR). Tissue samples were taken before and after applications of VLB, Cis-Platinum (CDP) and combined intraarterial chemotherapy (IAC) and incubated with the spin probe, the palmitic acid methylester spin label analog, MeFasl (10, 3) incorporating into the cell membranes. EPR spectra of the labelled tissue samples were measured. Within few days after application of the chemotherapeutic drugs some oscillations of the membrane fluidity in the tissue were observed, while after a longer period of few weeks the relative amount of cells with greater membrane fluidity was found to decrease. Furthermore, an unexpected gradual increase in the EPR signal intensity after incubation of the tissue with the spin probe, probably due to an oxidative process in this particular sarcoma tissue was observed. These data could be useful for understanding of drug induced changes in cell membranes and for future timing of drug treatments in combined schedules.