CALIBER: a phase II randomized feasibility trial of chemoablation with mitomycin-C vs surgical management in low-risk non-muscle-invasive bladder cancer.

OBJECTIVES: To evaluate the activity of intravesical mitomycin-C (MMC) to ablate recurrent low-risk non-muscle-invasive bladder cancer (NMIBC) and assess whether it may enable patients to avoid surgical intervention for treatment of recurrence. PATIENTS AND METHODS: CALIBER is a phase II feasibility study. Participants were randomized (2:1) to treatment with four once-weekly MMC 40-mg intravesical instillations (chemoablation arm) or to surgical management. The surgical group was included to assess the feasibility of randomization. The primary endpoint was complete response to intravesical MMC in the chemoablation arm at 3 months, reported with exact 95% confidence intervals (CIs). Secondary endpoints included time to subsequent recurrence, summarized by Kaplan-Meier methods. RESULTS: Between February 2015 and August 2017, 82 patients with visual diagnosis of recurrent low-risk NMIBC were enrolled from 24 UK hospitals (chemoablation, n = 54; surgical management, n =28). The median follow-up was 24 months. Complete response at 3 months was 37.0% (20/54; 95% CI 24.3-51.3) with chemoablation and 80.8% (21/26; 95% CI 60.6-93.4) with surgical management. Amongst patients with complete response at 3 months, a similar proportion was recurrence-free by 12 months in both groups (84%). Amongst those with residual disease at 3 months, the 12-month recurrence-free proportion was lower in the surgical management group (40.0%) than in the chemoablation group (84%). Recruitment stopped early as chemoablation did not meet the prespecified threshold of 45% complete responses at 3 months. CONCLUSION: Intravesical chemoablation in low-risk NMIBC is feasible and safe, but did not demonstrate sufficient response in the present trial. After chemoablation there may be a reduction in recurrence rate, even in non-responders, that is greater than with surgery alone. Further research is required to investigate the role and optimal schedule of neoadjuvant intravesical chemotherapy prior to surgery for NMIBC.

Inhibition of STAT signalling in bladder cancer by diindolylmethane: relevance to cell adhesion, migration and proliferation.

Effective treatments to prevent recurrence or progression of non-muscle-invasive bladder cancer, or to inhibit metastasis of muscle-invasive forms of the disease, would deliver significant patient benefit. Here the involvement of STAT signalling and the chemopreventive potential of diindolylmethane (DIM) in human bladder cancer were investigated. Muscle-invasive bladder cancer tissues were characterised by nuclear expression of phosphorylated STAT1, 3 and 5. In E-cadherin positive tumour cell lines (RT112, RT4, HT1376), STAT5 was constitutively phosphorylated, while E-cadherin negative lines (J82, T24, UMUC3) contained phosphoSTAT3. Knockdown of STAT3 induced G0/G1 arrest and inhibited adhesion in J82 cells. Knockdown of STAT1inhibited migration in J82 and RT112 lines. No significant increase in apoptosis was observed. In response to the Janus kinase inhibitor, AG490, RT112 and J82 cells initially underwent G0/G1 arrest, with RT112 cells subsequently exhibiting S phase arrest. Phosphorylation of STAT1(Tyr701), STAT3(Tyr705) and (Ser727) and STAT5(Tyr694) was inhibited by DIM, as was adhesion of J82 cells to collagen, an effect that was enhanced when STAT1 or 3 was reduced by siRNA. However, over-expression of STAT3C partially rescued the DIM inhibitory effect on collagen-mediated adhesion. Migration of both lines was inhibited by DIM, while transfection of constitutively active STAT3C enhanced migration of RT112 cells. DIM induced cell cycle arrest and apoptosis in three cell lines with different degrees of radioresistance. Taken together, these results suggest that inhibition of STAT signalling and/or treatment with DIM may decrease invasiveness of bladder cancer. DIM can induce apoptosis in cell lines which are radioresistant, so in combination with radiotherapy may be useful in overcoming such resistance.

SIP1 protein protects cells from DNA damage-induced apoptosis and has independent prognostic value in bladder cancer.

The epithelial-mesenchymal transition (EMT) contributes to cancer metastasis. Two ZEB family members, ZEB1 and ZEB2(SIP1), inhibit transcription of the E-cadherin gene and induce EMT in vitro. However, their relevance to human cancer is insufficiently studied. Here, we performed a comparative study of SIP1 and ZEB1 proteins in cancer cell lines and in one form of human malignancy, carcinoma of the bladder. Whereas ZEB1 protein was expressed in all E-cadherin-negative carcinoma cell lines, being in part responsible for the high motility of bladder cancer cells, SIP1 was hardly ever detectable in carcinoma cells in culture. However, SIP1 represented an independent factor of poor prognosis (P = 0.005) in a series of bladder cancer specimens obtained from patients treated with radiotherapy. In contrast, ZEB1 was rarely expressed in tumor tissues; and E-cadherin status did not correlate with the patients' survival. SIP1 protected cells from UV- and cisplatin-induced apoptosis in vitro but had no effect on the level of DNA damage. The anti-apoptotic effect of SIP1 was independent of either cell cycle arrest or loss of cell-cell adhesion and was associated with reduced phosphorylation of ATM/ATR targets in UV-treated cells. The prognostic value of SIP1 and its role in DNA damage response establish a link between genetic instability and metastasis and suggest a potential importance for this protein as a therapeutic target. In addition, we conclude that the nature of an EMT pathway rather than the deregulation of E-cadherin per se is critical for the progression of the disease and patients' survival.

Combined treatment of bladder cancer cell lines with lapatinib and varying chemotherapy regimens--evidence of schedule-dependent synergy.

OBJECTIVES: ErbB family members present an attractive target for therapeutic manipulation in bladder cancer. Lapatinib is an oral, small molecule, reversible dual inhibitor of ErbB1 (epidermal growth factor receptor) and ErbB2 (HER2) tyrosine kinases. Cisplatin-based combination chemotherapy has proven benefit in palliating symptoms and prolonging survival in patients with metastatic bladder cancer. In this study, we investigated the potential utility of lapatinib as an adjunct to chemotherapy in human bladder cancer cell lines. We also assessed whether these interactions were schedule dependent and synergistic. METHODS: We chose two bladder cancer cell lines, one (RT112) with high expression of ErbB1 and ErbB2 and one (J82) with low expression of these receptors. These cell lines were used to determine the growth inhibitory effects of lapatinib and the clinically relevant combination of gemcitabine and cisplatin (GC) chemotherapy. Four different schedules were assessed: GC alone (no lapatinib); lapatinib before and during GC; lapatinib concomitant with GC; and lapatinib after GC. RESULTS: Lapatinib reduced cell viability in both cell lines in a dose-dependent fashion. The values for the 50% inhibitory concentration for RT112 and J82 cells after lapatinib were similar. In both cell lines, the addition of lapatinib to GC potentiated the efficacy. The optimal sequence consisted of lapatinib before and during GC. Using this schedule, cooperation was synergistic. CONCLUSIONS: Our data present evidence that lapatinib cooperates with clinically relevant cytotoxic agents and may have therapeutic utility in the management of chemotherapy-naive metastatic bladder cancer. Lapatinib may also enable reduced-dose chemotherapy, a potential toxicity-sparing strategy.