The in vitro and in vivo anticancer activities of doxorubicin-loaded B16-F10 murine melanoma cells (DLTC) were evaluated. DLTC showed similar growth-inhibitory effects against live B16-F10 cells with doxorubicin solution in cell culture system, with the IC50 of 0.11 microM and 0.17 microM, respectively. However, DLTC demonstrated higher effectiveness than the free solution in treating mouse lung cancer caused by live B16-F10 cells. Syngeneic C57BL mice were inoculated intravenously with live B16-F10 cells first, and then received daily treatment of intravenous injections of doxorubicin in either DLTC or free solution form. Compared with the control group treated with phosphate-buffered saline, DLTC eradicated almost all the lung cancer colonies (>99%), while the free solution form reduced the colonies by 61%, when the treatment was given at an early stage. If the treatment started after the establishment of micrometastatic colonies in the mouse lungs, DLTC and free solution treatment resulted in 85% and 30% cancer reduction, respectively. Additional experiments demonstrated that the reduction of lung cancer colonies by DLTC was related to the initial treatment time: the earlier the treatment, the greater the effect. In conclusion, DLTC showed better therapeutic outcomes than free solution form in treating lung cancer of our animal model.

A drug-loaded tumor cell (DLTC) system has been developed for lung metastasis-targeting drug delivery. Doxorubicin was loaded into B16-F10 murine melanoma cells (96 microg/10(6) cells). The loading process led to the death of all the carrier cells. The diameter of DLTC was 15.03+/-2.36 microm (mean +/- SD). The amount and rate of doxorubicin being released from the DLTC mainly depended on the drug loading and carrier cell concentration. Over a 6-month storage in phosphate buffered saline (PBS) at 4 degrees C, the decrease in intracellular drug concentration and the carrier cell number were less than 25% and 5%, respectively. After a bolus injection of 30 microg doxorubicin in either DLTC form or free solution into the mice tail veins, drug deposit in the lung from DLTC was 3.6-fold of that achieved by free drug solution. The latter resulted in higher drug content in liver and spleen. Extensive trypsinization of DLTC reduced its lung targeting effect by 30%, and the density of surface adhesion molecule GM3 on DLTC surface by 25%. In conclusion, this DLTC system demonstrated a lung-targeting activity that may be partially attributed to its specific surface characteristics.

133 Moderate exercise training is believed to enhance certain aspects of the adaptive immune system. However, it is uncertain how chronic exposure to a transplanted prostate cancer may affect the immune system of a trained animal. This study examined the effects of voluntary wheel running on the percentage of splenic lymphocyte subpopulations in rats with transplanted prostate cancer. Animals were randomly assigned to running wheel (RW:n=10) or control (C:n=9) groups. The RW animals were given free access to the running wheels for 11 weeks. At the start of week 12, all animals were inoculated with 1×106 transplantable rat prostate cancer cells subcutaneously on the back. The RW animals were sacrificed at the conclusion of week 19. Splenocytes were collected and first stained with FITC or Biotin conjugated antibodies, then with Phycoerythrin (PE) or Streptavidin-CyChrome secondary reagents. Gated lymphocytes were electronically characterized by Fluorescence intensity in all 3 stains (FITC, Biotin-Avidin, PE), two stains at a time: FITC×BA, FITC×PE, BA×PE. Results are reported as percent positive for individually-stained subpopulations (T helper, CD4; T cytotoxic, CD8; macrophages, MO; B cells), percent of each subpopulations which also bore an activation marker [Interleukin-2 receptor (IL2R), MHCH], and for two subpopulations that bore the same activation marker. Results: C had a greater (p<0.05) percentage of MO, activated MO and activated cells (CD4+IL2R and CD8+IL2R). C tended (p=0.07) to have higher levels of activated B and MO (B+MHCH, MO+MHCH) and percentage of CD4+IL2R cells. However, RW tended (p=0.07) to have a higher percentage of CD8 cells. No difference was observed in the percentage of total CD4 or B cells. Conclusion: Voluntary running-wheel exercise for 19 weeks appeared to suppress a certain percentage of splenocyte cells (MO, activated MO and CD4+IL2R and CD8+IL2R) involved in antigen-specific responses capable of modifying tumor growth in rats with prostate cancer.

INTRODUCTION AND OBJECTIVE Photodynamic therapy (PDT) combines a photosensitizer such as Photofrin with red laser light (630 nm) to destroy cancer cells. Investigators have reported effectiveness of PDT in the management of patients with recurrent superficial bladder cancer. We retrospectively reviewed our experience in 58 patients to assess the long-term role of PDT in the management of resistant superficial transitional cell carcinoma (TCC) including Ta, T1, and refractory carcinoma in situ (CIS) of the urinary bladder. MATERIALS AND METHODS All 58 patients had failed at least one course of standard intravesical therapy or had contraindication for intravesical chemo- or immunotherapy. Patients with malignancy present (Ta-T1/Grade I-III, CIS) were accepted for ablative PDT. Patients undergoing prophylactic PDT after complete resection were confirmed to be tumor-free by cystoscopy and bladder was cytology before PDT. Post-PDT evaluations included weekly telephone contact to assess acute adverse reactions and assessment of efficacy and bladder toxicity at three months and quarterly thereafter. RESULTS These 58 patients underwent a single PDT treatment with 2.0 or 1.5 mg/kg of Photofrin and 10-60 J/cm2 light (630 nm). At three months, complete response rates were 84% and 75% for residual resistant papillary TCC and refractory CIS respectively; and 90% of patients treated prophylactically had not had recurrences. At a median followup of 50 months (range 9-110), 59% (34/58) of the responders are alive, with 31/34 still disease-free. CONCLUSION PDT using 1.5 mg/kg of Photofrin and 15 J/cm2 of light (630 nm) should be considered a safe and effective treatment for refractory CIS or recurrent papillary TCC.

The role of transferrin receptor-mediated endocytosis in promoting murine bladder tumor cell (MBT2) uptake of liposomes and the antiproliferative effect of liposome-entrapped alpha-interferon (alpha-IFN) against MBT2 were investigated. Liposomes (0.11 microm) were prepared using phosphatidylcholine and phosphatidylserine in a molar ratio of 7:3, with or without surface conjugation of transferrin-polylysine (TFPL). The uptake of plain liposomes (without TFPL) by MBT2 was less than 5% after incubation for 48 h. In contrast, cell uptake of TFPL-liposomes was markedly enhanced by TFPL in a dose-dependent manner and reached plateau levels in 24 h. This increase was partially blocked by the addition of free transferrin, suggesting that the uptake process involves transferrin receptor-mediated endocytosis. The antiproliferative activity of alpha-IFN (100-200 U/well), delivered via plain liposomes, measured against blank liposome control, was in the range of 25-35%, which was similar to that of free alpha-IFN. In comparison, inhibition of cell proliferation by same concentrations of alpha-IFN delivered by TFPL-liposomes was 90-100%. These results show a strong correlation between antiproliferative activity and the uptake of liposomes by the tumor cells, indicating that TFPL-liposomes promote intracellular delivery of alpha-IFN and enhance the effect of alpha-IFN against MBT2 cell growth. The potential cytotoxicity of drug-free liposomes was also investigated. Liposomes containing various concentrations of TFPL showed significant dose- and time-dependent antiproliferative activity against MBT2. This effect maybe attributed to lipidosis and/or the destruction of intracellular cycle of iron transport.

We postulated that sequential whole bladder photodynamic therapy (WBPDT) treatments with a low WBPDT dose would result in improved safety profile and good local tumor control. However, the drawback with such a proposal is the potential cumulative effect of sequential WBPDT treatments on bladder function. We designed this preclinical study to determine the safety of sequential WBPDT treatments. Six female dogs underwent a single WBPDT treatment comprising 1.5 mg/kg of Photofrin® and 15 J/cm(2) of light. Four dogs received a second treatment; and three dogs received three treatments. Pre- and post-WBPDT evaluations included cystoscopy and saline cystometry at baseline, 1 week, and 12 weeks. Gross and histopathologic analysis of cystectomy specimens occurred at 1 and 12 weeks. A single photodynamic therapy (PDT) treatment induced average bladder capacity losses of 11% (0-33) and 0% at post-WBPDT weeks 1 and 12, respectively. A second sequential WBPDT treatment caused average bladder capacity losses of 36% (0-57%) and 17% (2-24%) at weeks 1 and 12, respectively. Three sequential WBPDT treatments induced average bladder capacity losses of 22% (0-42) and 0% at weeks 1 and 12, respectively. Full recovery in bladder capacity occurred in all cases except after the second sequential treatment, which induced a persistent bladder capacity loss of 17% at 12 weeks. Histopathologic analysis of cystectomy specimens revealed a focal discernible injury to the superficial muscle in only one of the dogs that received three treatments. We conclude that sequential WBPDT treatments using low dose PDT Photofrin® (1.5 mg/kg and light ≤15 J/cm(2)) is safe, and we recommend using this low WBPDT dose in clinical investigation.