[In vitro culture of malignant tumor tissues from the human urinary tract (author's transl)]

Enhanced antitumor efficacy of integrin-targeted oncolytic adenovirus AxdAdB3-F/RGD on bladder cancer

OBJECTIVE

To evaluate the therapeutic efficacy of AxdAdB-3 with Arg-Gly-Asp (RGD)-fiber modification (AxdAdB3-F/RGD), which enables integrin-dependent infection in bladder cancers.

METHODS

Flow cytometric analysis was applied to evaluated adenovirus-mediated gene transduction into various cells. The cytopathic effects of AxdAdB3-F/RGD were evaluated in bladder cancer cell lines and a normal bladder mucosa-derived cell line (HCV29) with AxCAZ3-F/RGD (control) or AxdAdB-3. The efficacy of bladder instillation therapy with AxdAdB3-F/RGD for orthotopic bladder cancer was investigated in nude mice.

RESULTS

Expression of coxsackievirus adenovirus receptor (CAR) and integrins (αvβ3 and αvβ5) vary in different bladder cancer cell lines. The susceptibility of various cell lines to adenovirus was associated with the expression of CAR. AxdAdB-3 was more cytopathic in CAR-positive bladder cancer cells than in CAR-negative cells, whereas AxdAdB3-F/RGD caused effective oncolysis in both CAR-positive and CAR-negative bladder cancer cells. AxdAdB3-F/RGD was not cytotoxic to HCV29 cells. Direct instillation of AxdAdB3-F/RGD into the bladder of the orthotopic model, established by CAR-deficient human bladder cancer cells, inhibited tumor growth and led to significantly elongated survival.

CONCLUSION

E1A and E1B double-restricted oncolytic adenovirus with RGD fiber modification has enhanced infectivity and oncolytic effects to CAR-deficient bladder cancers, suggesting the therapeutic potential of AxdAdB3-F/RGD for bladder cancers.

Inositol 1,4,5-trisphosphate (IP3) receptor type1 (IP3R1) modulates the acquisition of cisplatin resistance in bladder cancer cell lines

To investigate the molecules that regulate the acquisition of cis-diamminedichloroplatinum (II) (cisplatin) resistance, we performed cDNA microarrays using two pairs of parental and cisplatin-resistant bladder cancer cell lines. We found a markedly reduced expression of inositol 1,4,5-trisphosphate (IP3) receptor type1 (IP3R1), endoplasmic reticulum membrane protein, in cisplatin-resistant cells. The suppression of IP3R1 expression using small interfering RNA in parental cells prevented apoptosis and resulted in decreased sensitivity to cisplatin. Contrarily, overexpression of IP3R1 in resistant cells induced apoptosis and increased sensitivity to cisplatin. These results suggest that cisplatin-induced downregulation of IP3R1 expression was closely associated with the acquisition of cisplatin resistance in bladder cancer cells.

Reversal of P-glycoprotein-mediated paclitaxel resistance by new synthetic isoprenoids in human bladder cancer cell line

We isolated a paclitaxel-resistant cell line (KK47/TX30) from a human bladder cancer cell line (KK47/WT) in order to investigate the mechanism of and reversal agents for paclitaxel resistance. KK47/TX30 cells exhibited 700-fold resistance to paclitaxel and cross-resistance to vinca alkaloids and topoisomerase II inhibitors. Tubulin polymerization assay showed no significant difference in the ratio of polymerized alpha- and beta-tubulin between KK47/WT and KK47/TX30 cells. Western blot analysis demonstrated overexpression of P-glycoprotein (P-gp) and lung resistance-related protein (LRP) in KK47/TX30 cells. Drug accumulation and efflux studies showed that the decreased paclitaxel accumulation in KK47/TX30 cells was due to enhanced paclitaxel efflux. Cell survival assay revealed that verapamil and cepharanthine, conventional P-gp modulators, could completely overcome paclitaxel resistance. To investigate whether new synthetic isoprenoids could overcome paclitaxel resistance, we synthesized 31 isoprenoids based on the structure of N-solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine (SDB), which could reverse multidrug resistance (MDR), as shown previously. Among those examined, trans-N,N'-bis(3,4-dimethoxybenzyl)-N-solanesyl-1,2-diaminocyclohexane (N-5228) could completely reverse paclitaxel resistance in KK47/TX30 cells. N-5228 inhibited photoaffinity labeling of P-gp by [(3)H]azidopine, suggesting that N-5228 could bind to P-gp directly and could be a substrate of P-gp. Next, we investigated structural features of these 31 isoprenoids in order to determine the structural requirements for the reversal of P-gp-mediated paclitaxel resistance, suggesting that the following structural features are important for overcoming paclitaxel resistance: (1) a basic structure of 8 to 10 isoprene units, (2) a cyclohexane ring or benzene ring within the framework, (3) two cationic sites in close proximity to each other, and (4) a benzyl group with 3,4-dimethoxy functionalities, which have moderate electron-donating ability. These findings may provide valuable information for the development of P-gp-mediated MDR-reversing agents.

Glycolipid composition in bladder tumor: a crucial role of GM3 ganglioside in tumor invasion

Glycolipids were extracted from primary bladder tumors of 14 patients and 2 normal counterparts. Their expression pattern was assessed by thin-layer chromatography (TLC). The most remarkable change was massive accumulation of GM3 in superficial bladder tumors compared with invasive tumors. This change was also confirmed by immunohistochemistry using anti-GM3 monoclonal antibody. The activities of glycosyltransferases responsible for GM3 synthesis (GM3 synthase, Gb3 synthase and GD3 synthase) were consistent with upregulated expression of GM3 in superficial tumors. It was suggested that the marked GM3 accumulation in superficial tumors was caused not only by upregulated GM3 synthase but also by downregulated activities of Gb3 and GD3 synthase. Histopathologic examination revealed an inverse correlation of the amount of GM3 expressed with invasive potential. Exogenously supplemented GM3 suppressed invasion potential in human bladder tumor cell lines (T-24, KK-47). These results indicate that the amount of GM3 expressed may serve as an indicator of the invasion potential of bladder tumor. Furthermore, new antiinvasion therapeutics may be possible by administration of GM3.

Cytokine-mediated antitumor effect of OK-432 on urinary bladder tumor cells in vitro

Fatal complications from the intravesical instillation of bacillus Calmette-Guérin (BCG) for the treatment of superficial urinary bladder tumors have been reported. OK-432, an immunomodulating agent like BCG, may be an effective and safe agent for the treatment of urinary bladder tumors. We investigated the cytokine-mediated antitumor effect of OK-432 on established human bladder cancer cell lines (T24 and KK-47) in vitro. Peripheral blood mononuclear cells (PBMCs) from a healthy volunteer were cultured with OK-432 for various periods, and the culture supernatants were used as conditioned media. Cytokines in the culture supernatants were quantified. The antitumor effect of OK-432 was evaluated by colony-forming assays, using the conditioned media as the culture media. The colony survival of T24 and KK-47 cells was significantly inhibited by conditioned media from 24-h cultures of PBMCs incubated with OK-432 at concentrations of 0.05 and 0.1 Klinische Einheit (KE)/ml. Conditioned media from PBMCs cultivated with OK-432 for 7 days at 0.01 and 0.05 KE/ml also significantly inhibited the colony survival of both cell lines. Higher concentrations of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) were detected in conditioned media cultivated with OK-432 for 24 h than in media from PBMCs alone. However, higher concentrations of interferon gamma (IFN gamma) were detected in conditioned media cultivated with OK-432 for 7 days. Approximately 90% of the inhibition of KK-47 cells by the 24-h conditioned media was neutralized by an anti-TNF monoclonal antibody. The inhibition of T24 cells was neutralized approximately 50% by the same antibody. The inhibition of T24 and KK-47 cells by 7-day conditioned media was completely neutralized by an anti-IFN gamma monoclonal antibody. The cultivation of PBMCs with OK-432 inhibited the production of granulocyte-colony-stimulating factor (G-CSF) by PBMCs. The inhibition may play a role in the mechanism of the antitumor effect of OK-432. Urinary bladder tumor cell lines have different sensitivities to cytokines. The cytokines induced by OK-432 vary with the concentration of OK-432 and the culture period. It is suggested that in intravesical instillation of OK-432 for treatment of urinary bladder tumor, the optimal dose and interval of instillation should be considered.

Ultraweak biophoton emission imaging of transplanted bladder cancer

Biophoton emission or spontaneous ultraweak light emission has been observed from almost all living organisms, with intensities ranging from 10(-19) to 10(-16) W/cm2. The measurement of biophoton emission offers the attractive possibility of noninvasive monitoring of the underlying physiological function of a living system. In the present study, ultraweak biophoton emission from mice with transplanted bladder cancer was detected by a two-dimensional photon-counting system. Photon counts were observed to be 1.51-4.73 times higher from the regions of untreated tumor than from normal regions. Our study suggests that this novel technique may be applicable to the diagnosis of superficial tumors.

Expression of multidrug resistance-associated protein (MRP), MDR1 and DNA topoisomerase II in human multidrug-resistant bladder cancer cell lines

The acquisition of the multidrug resistance phenotype in human tumours is associated with an overexpression of the 170 kDa P-glycoprotein encoded by the multidrug resistance 1 (MDR1) gene, and also with a 190 kDa membrane ATP-binding protein encoded by a multidrug resistance-associated protein (MRP) gene. Human bladder cancer is a highly malignant neoplasm which is refractory to anti-cancer chemotherapy. In order to understand the mechanism underlying multidrug resistance in bladder cancer, we established three doxorubicin-resistant cell lines, T24/ADM-1, T24/ADM-2 and KK47/ADM, and one vincristine-resistant cell line, T24/VCR, from human bladder cancer T24 and KK47 cells respectively. Both T24/ADM-1 and T24/ADM-2 cells which had elevated MRP mRNA levels showed both a cross-resistance to etoposide and a decreased intracellular accumulation of etoposide. T24/VCR cells which had elevated levels of MDR1 mRNA and P-glycoprotein but not of MRP mRNA, showed cross-resistance to doxorubicin. On the other hand, KK47/ADM cells, which had elevated levels of both MRP and MDR1 mRNA and a decreased level of topoisomerase II mRNA, were found to be cross-resistant to etoposide, vincristine and a camptothecin derivative, CPT-11. Our present study demonstrates a concomitant induction of increased levels of MRP mRNA, decreased levels of topoisomerase II mRNA and decreased drug accumulation during development of multidrug resistance in human bladder cancer cells. The enhanced expression of the MRP gene is herein discussed in a possible correlation with the decreased expression of the topoisomerase II gene.

Direct and indirect effects of recombinant human granulocyte-colony stimulating factor on in vitro colony formation of human bladder cancer cells

Although the present experimental use of recombinant human granulocyte-colony-stimulating factor (rG-CSF) has been proven to alleviate the myelosuppression induced by antitumor chemotherapy, it is also believed to stimulate growth of some nonhematopoietic tumor cells. We investigated both the direct and indirect effects of rG-CSF on in vitro colony formation of human bladder cancer cell lines using a modified human tumor clonogenic assay. Peripheral blood mononuclear cells (PBMC) were used as feeder cells (a mixture of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish obtained from healthy donors). Human bladder cancer cell lines KK-47, TCCSUP and T24, all derived from human transitional-cell carcinomas, were incubated continuously with various concentrations of rG-CSF ranging from 0.01 ng/ml to 10 ng/ml both with and without PBMC for 7-21 days. The concentrations of rG-CSF used were chosen as being in the range of achievable serum concentrations in patients treated with rG-CSF. At the end of incubation, colonies were counted under an inverted phase-contrast microscope, and an increase in the number of colonies in comparison with the control was used to evaluate the effects of rG-CSF. Results were expressed as a percentage of controls. rG-CSF in the upper layer at concentrations ranging from 0.1 ng/ml to 10 ng/ml stimulated the colony formation of all the cancer cell lines tested in the absence of PBMC in the feeder layer, whereas cells with PBMC in the feeder layer were significantly stimulated more than those without PBMC in the feeder layer (P < 0.05) up to a certain concentration, which varied from cell line to cell line. At higher concentrations of rG-CSF, no further stimulation but, on the contrary, a decrease in colony formation was observed in cells with PBMC in the feeder layer in all the cell lines tested. Colony formation in KK-47 and T24 cell lines was significantly inhibited at 5 ng/ml and/or 10 ng/ml rG-CSF compared with cells without PBMC in the feeder layer. Our results suggest that rG-CSF may have both direct and indirect stimulatory effects on the growth of human bladder cancer cell lines in vitro. The results obtained also raise the possibility of adverse effects of rG-CSF in bladder cancer patients whose malignant cells may be directly and indirectly stimulated by this factor while it is being used clinically to alleviate the myelosuppression induced by antitumor chemotherapy.

Studies of effects of anticancer agents in combination with/without hyperthermia on metastasized human bladder cancer cells in chick embryos using the polymerase chain reaction technique

Cultivated T24 cells derived from a human bladder cancer were inoculated into the chorioallantoic membrane vein of chick embryos. Hyperthermic treatment was performed following injection of anticancer agents 3 days after the inoculation of the T24 cells. DNA samples were obtained from the livers of the chick embryos, and the polymerase chain reaction technique was used to amplify a DNA fragment specific to the human beta-globin gene. The Southern hybridization method was used to evaluate the inhibitory effects of anticancer agents in combination with/without hyperthermia on T24 cells metastasized to the liver. The hyperthermia exerted an inhibitory effect on the growth of the T24 cells in the livers of the chick embryos, and this was dependent on the thermal dose. The antitumor effects of hyperthermia performed at 42.5 degrees C for 20 min and at 43.0 degrees C for 10 min were evidenced by 69.2% an 82.0% inhibition of the growth of the metastasized T24 cells, respectively, as compared with the growth of untreated T24 cell. Hyperthermia performed at 42.5 degrees C for 10 min alone produced 26.7% tumor growth inhibition, and these conditions for hyperthermia were subsequently used as a criterion for evaluating the effects of its combination with various anticancer agents. Adriamycin (20 micrograms/egg) alone, mitomycin C (10 micrograms/egg) alone, carboplatin (10 micrograms/egg) alone, and cisplatin (10 micrograms/egg) alone produced 13.5%, 58.9%, 27.3%, and 29.1% tumor growth inhibition, respectively. Adriamycin and mitomycin C applied in combination with hyperthermia showed additive inhibitory effects on the growth of the metastasized T24 cells in this chick embryo model.

Possible advantages of aluminum-chloro-tetrasulfonated phthalocyanine over hematoporphyrin derivative as a photosensitizer in photodynamic therapy

The potency of aluminum-chloro-tetrasulfonated phthalocyanine (AlS4Pc) as a photosensitizer in photodynamic therapy was evaluated in in vitro and in vivo studies. Compared with hematoporphyrin derivative (HpD), the following advantages of AlS4Pc were revealed: (1) AlS4Pc was less toxic than HpD in vitro without light irradiation. (2) AlS4Pc showed more photodynamic-dependent cytotoxicity and anti-tumor effect in the red area of the spectrum (> 660 nm) at which tissue penetration is high. (3) AlS4Pc appeared to be removed more rapidly from normal tissues such as muscle and skin. (4) AlS4Pc showed less photodynamic-dependent cytotoxicity in vitro and milder cutaneous phototoxicity in vivo with UVA irradiation. On the basis of these observations, AlS4Pc shows considerable promise as a photosensitizer for PDT.

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.

Establishment and Characterization of Doxorubicin-Resistant Human Bladder Cancer Cell Line, Kk47/adm

A human bladder cancer cell line resistant to doxorubicin, KK47/ADM has been established in vitro by exposing KK47 parent cells to progressively higher concentrations of the drug over a period of 16 months. The KK47/ADM was 271 times more resistant to doxorubicin than the KK47 parent. The KK47/ADM exhibited cross-resistance to doxorubicin derivatives (pirarubicin, epirubicin), vinca alkaloids (vinblastine, vincristine) and etoposide, but not to cisplatin, carboplatin, mitomycin C, peplomycin and methotrexate. Unlike the KK47 parent, about 70% of the KK47/ADM cells showed a positive reaction with monoclonal antibody against P-glycoprotein, MRK16. Uptake and efflux studies with [14C]doxorubicin indicated that the resistance exhibited by the KK47/ADM line was mainly due to a lower accumulation of the drug caused by an increased active efflux, and these were reversed in the presence of verapamil. Although verapamil enhanced doxorubicin sensitivity of KK47/ADM, a complete overcoming of the resistance could not be obtained. These two lines with different chemosensitivity are thus considered to be a useful model for developing new chemotherapeutic strategies against multidrug resistant bladder cancer.

Responses of tumour cell lines implanted onto the chorioallantoic membrane of chick embryo to anticancer agents in combination with hyperthermia

The chorioallantoic membrane of chick embryos was used to examine the responses of three tumour cell lines to anticancer agents, alone and in combination with hyperthermia. Fifteen minutes of hyperthermia at 42.5 degrees C produced the most favourable anticancer effect in the B16-F10 grafts. The use of Adriamycin (ADM) alone and the combined use of hyperthermia and either cisplatin (CDDP), cyclophosphamide (CY) or ADM resulted in a significantly higher rate of tumour regression in the B16-F10 grafts from a murine melanoma. In the KK-47 grafts derived from a transitional cell carcinoma of the bladder, the use of CY alone and the combination of CY and hyperthermia produced a significant tumour regression rate. In the T24 grafts neither the use of CY or CDDP alone, nor the combination of these drugs with hyperthermia demonstrated any significant effect. This method of screening anticancer agents was found to be rapid, simple to perform and inexpensive.

Photodynamic cell killing effects and acute skin photosensitivity of aluminum-chloro-tetrasulfonated phthalocyanine and hematoporphyrin derivative

Aluminum-chloro-tetrasulfonated phthalocyanine (PC) showing an absorption peak at 678 nm was compared to hematoporphyrin derivative (HpD), a photosensitizer commonly used in the photodynamic therapy (PDT) of cancers.

IN VITRO STUDIES

KK-47 cells were exposed to long-wavelength ultraviolet (UVA) or red light (greater than 600 nm, greater than 640 nm and greater than 660 nm) after drug sensitization. With UVA irradiation, a higher photodynamic cell killing effect was observed in the cells treated with HpD than with PC. However, with red light irradiation (both greater than 640 nm and greater than 660 nm) PC resulted in greater cell damage. PC was less toxic to KK-47 cells in the dark. In vivo studies: Using a gold vapor laser (GVL: 627.8 nm, 200 mW/cm2, 200 J/cm2), the photodynamic tumor response was determined in C3H/He mice bearing transplantable squamous cell carcinoma. No significant difference was observed in the tumor volume between the PC and HpD groups, except that the PC group (10.0 mg/kg body weight) showed a significantly higher remission rate (3/6) than the control group (0/10, P less than 0.05). Skin photosensitivity test: Skin photosensitivity was estimated by measuring changes in back skin thickness due to photosensitization. With UVA irradiation, a stronger skin reaction was observed in the HpD group, while with visible light irradiation there was no significant difference between the HpD and PC groups. Based on the superior cell killing effect with red light, reduced toxicity to the cells in the dark and mild skin reaction with UVA, PC may be a more promising photosensitizer for PDT.

A combined therapy of hyperthermia and tumor necrosis factor for nude mice bearing KK-47 bladder cancer

A combined therapy of hyperthermia (43.5 C) and tumor necrosis factor (10(3) and 10(4) units) for the treatment of experimental bladder carcinoma KK-47 in athymic mice was studied. Briefly, mice were injected subcutaneously with 10(7) disaggregated cells. When the tumors were 250 mm3 in size, tumor necrosis factor was administered, either intravenously or by intratumor injection. Intravenous injection was 10(3) to 10(4) units tumor necrosis factor in the tail vein and intratumor was 10(3) to 10(4) units injected directly into the center of the tumor. Immediately following injection, the tumor bearing leg was placed in a 43.5 C water bath for 20 minutes. Tumor size was monitored once a week for seven weeks and the animals were divided into control, hyperthermia alone, tumor necrosis factor alone and combined therapy. Results of the study showed no significant difference in 10(3) units of tumor necrosis factor intravenously versus control but a significant regression in hyperthermia alone. Anti-tumor effects significantly increased in hyperthermia plus 10(3) units tumor necrosis factor versus hyperthermia alone. Similar results were seen with 10(4) units tumor necrosis factor intravenously though in the combination group of hyperthermia and tumor necrosis factor, eight mice of eight died one to three days following treatment. In those receiving intratumor injections, there was no difference between tumor necrosis factor or control. Tumor necrosis factor with hyperthermia had the approximate same characteristics as hyperthermia alone and therefore there was no synergistic finding. These results reflect on the suggestion that the combination therapy of hyperthermia and systemic administration of the proper dosage of tumor necrosis factor may produce synergistic anti-cancer effects in bladder cancer patients.