Double short-time exposure to pirarubicin produces higher cytotoxicity against T24 bladder cancer cells

Safety and efficacy of intensive instillation of low-dose pirarubicin vs. bacillus Calmette-Guérin in patients with high-risk non-muscle-invasive bladder cancer

OBJECTIVES

To evaluate the safety and efficacy of intensive intravesical instillation of low-dose pirarubicin (THP) for 6 times vs. bacillus Calmette-Guérin (BCG) without maintenance therapy after transurethral resection of bladder tumor (TURBT) in patients with primary high-risk non-muscle-invasive bladder cancer (NMIBC).

MATERIALS AND METHODS

We retrospectively evaluated 370 patients with primary high-risk NMIBC who underwent TURBT from November 1993 to April 2019. The patients were divided into 2 groups: patients treated with intravesical instillation of BCG without maintenance therapy (BCG group) and intensive intravesical instillation of low-dose (20 mg) THP for 6 times within 10 days after TURBT (THP group). Safety was assessed using the Common Terminology Criteria for Adverse Events version 5.0. Background-adjusted multivariate analyses were performed to evaluate the effect of intensive intravesical instillation of low-dose THP on oncological outcomes, including intravesical recurrence-free survival (RFS), upper urinary tract RFS, muscle-invasive bladder cancer-free survival, metastasis-free survival, cancer-specific survival, and overall survival.

RESULTS

Of the 370 patients with primary high-risk NMIBC, 180 (49%) and 190 (51%) were stratified into the BCG and THP groups, respectively. The incidence rate of adverse events of any grade in the BCG group was significantly higher than that in the THP group (P < 0.001). In the background-adjusted multivariate analyses, no significant differences were observed in oncological outcomes between the BCG and THP groups.

CONCLUSIONS

Intensive intravesical instillation of low-dose THP for 6 times may be one of the treatment options in view of safety and efficacy after TURBT in patients with primary high-risk NMIBC.

Prospective randomized controlled trial of postoperative early intravesical chemotherapy with pirarubicin (THP) for solitary non-muscle invasive bladder cancer comparing single and two-time instillation

PURPOSE

Single immediate intravesical instillation of chemotherapy after transurethral resection of bladder tumor (TURBT) has been the gold standard treatment for patients with low- and intermediate-risk non-muscle invasive bladder cancer (NMIBC). Herein, we conducted a multicenter prospective randomized controlled trial in Japan, comparing recurrence-free survival between single and two-time instillation of pirarubicin (THP) for solitary NMIBC.

METHODS

Between 2005 and 2009, 257 patients with solitary NMIBC were enrolled and randomized to single instillation of THP (30 mg/50 mL) immediately after TURBT (Group A) or two-time instillation of THP immediately after and 1 day after TURBT (Group B). The primary endpoint was recurrence-free survival. Secondary endpoints included rates of recurrence and adverse effects, including hematuria, micturition pain, difficult urination, pollakiuria, systemic symptoms, and other complications. This study was registered as UMIN C000000266.

RESULTS

Of 257 patients, 99 in Group A and 102 in Group B could be evaluated for recurrence. Median follow-up was 71 months. The overall recurrence rate was 39 and 31%, respectively (p = 0.2704). Although the 5-year recurrence-free survival rates were 55.9% and 67.7% in groups A and B, respectively, the difference between groups was not significant (p = 0.2031). No significant differences in adverse effects were observed between groups, except for pollakiuria (7 vs 22%, p = 0.0031). Multivariate analyses did not show that the treatment group was a significant risk factor for bladder cancer recurrence.

CONCLUSIONS

Postoperative two-time intravesical instillation of THP was not superior to single immediate instillation for preventing recurrence after complete resection of a solitary NMIBC.

High-dose chemotherapeutics of intravesical chemotherapy rapidly induce mitochondrial dysfunction in bladder cancer-derived spheroids

Non-muscle invasive bladder cancer is treated with intravesical chemotherapy (IVC) after transurethral resection (TUR) to reduce the probability of recurrence. Despite improvement, the recurrence rate remains high. Intravesical chemotherapeutics at high doses are expected to ablate unresected tumors and floating cancer cells after TUR, although the fate of bladder cancer cells exposed to high-dose chemotherapeutics remains unclear. In this study, we utilized cancer tissue-originated spheroids (CTOS) prepared from bladder cancers or patient-derived xenografts, which may recapitulate human tumors better than 2-D cultures of established cell lines. We exposed CTOS to 1 mg/mL of epirubicin (EPI) or mitomycin C (MMC) for 2 h. EPI was promptly and homogeneously distributed into cancer cells in the CTOS. Two hours after exposure to MMC, the mitochondrial membrane potential decreased and the mitochondria were fragmented, while plasma membrane integrity was maintained. ATP levels rapidly decreased in CTOS after exposure to EPI or MMC. Although activation of the apoptotic pathway was confirmed by the advent of cleaved poly (ADP-ribose) polymerase, fragmentation of DNA (a hallmark of apoptosis) was not observed in CTOS after exposure to EPI and MMC. In the CTOS prepared directly from 19 surgical specimens exposed to EPI and MMC, the decrease of ATP levels varied among patients. Further establishment of the test might help the drug selection and the prediction of recurrence for individual patients.

Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest

AIM

Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored.

METHODS

Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses.

RESULTS

MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200-1000 ng/mL) inhibited the cell proliferation in time- and concentration-dependent manners. THP (50-500 ng/mL) induced MG63/DOX cell cycle arrest at the G(2)/M phase in time- and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200-1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr(161). Conversely, the treatment increased the phosphorylated Cdc2 at Thr(14)/Tyr(15) and Cdc25C at Ser(216), which led to a decrease in Cdc2-cyclin B1 activity.

CONCLUSION

The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G(2)/M phase, which supports the use of THP for managing patients with MDR osteosarcoma.

Intravesical administration of pirarubicin against superficial bladder cancer: Relationship between tumor tissue concentration and exposure time in the bladder or therapeutic effect

The aim of this study was to investigate the relationship between tissue concentrations and exposure times or therapeutic effect of an anthracycline anticancer drug, pirarubicin, in bladder cancer tissue after single intravesical administration against superficial bladder cancer. The concentrations of pirarubicin in tumor tissues and serum were measured at designated collection times after a single intravesical administration of pirarubicin (30 mg) in 22 patients with superficial bladder cancer. A wide range of concentrations of pirarubicin in bladder cancer tissue was observed (2.3-125 μg/g of tissue), although serum pirarubicin concentrations were not detected in any of the patients. Recurrence of superficial bladder cancer after transurethral resection of the bladder tumor (TUR-BT) was observed in 2 patients (9%). The concentration of pirarubicin in the tumor tissue tended to be higher as the exposure time increased. There was a weak relationship between the pirarubicin tissue concentration and tumor size. However, no significant relationship between tissue pirarubicin concentrations and the prophylactic effect against intravesical recurrence of bladder cancer after TUR-BT was observed. All patients had no adverse events, such as bladder irritation and local toxicity, caused by the treatment with pirarubicin. These findings suggest that prior to single intravesical administration of pirarubicin to patients with superficial bladder cancer the exposure time and tumor size should be considered.