Increased Anticancer Efficacy of Intravesical Mitomycin C Therapy when Combined with a PCNA Targeting Peptide

Odrun A Gederaas; Caroline D Søgaard; Trond Viset; Siri Bachke; Per Bruheim; Carl-Jørgen Arum; Marit Otterlei

doi:10.1016/j.tranon.2014.10.005

Increased Anticancer Efficacy of Intravesical Mitomycin C Therapy when Combined with a PCNA Targeting Peptide

Transl Oncol. 2014 Dec;7(6):812-23. doi: 10.1016/j.tranon.2014.10.005.

Authors

Odrun A Gederaas¹, Caroline D Søgaard¹, Trond Viset², Siri Bachke¹, Per Bruheim³, Carl-Jørgen Arum⁴, Marit Otterlei⁵

Affiliations

¹ Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
² Department of Pathology and Medical Genetics, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
³ Department of Biotechnology, Norwegian University of Science and Technology, Trondheim Norway.
⁴ Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Urology and Surgery, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
⁵ Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; APIM Therapeutics A/S, Trondheim, Norway. Electronic address: marit.otterlei@ntnu.no.

Abstract

Non-muscle-invasive bladder cancers (NMIBCs) are tumors confined to the mucosa or the mucosa/submucosa. An important challenge in treatment of NMIBC is both high recurrence and high progression rates. Consequently, more efficacious intravesical treatment regimes are in demand. Inhibition of the cell's DNA repair systems is a new promising strategy to improve cancer therapy, and proliferating cell nuclear antigen (PCNA) is a new promising target. PCNA is an essential scaffold protein in multiple cellular processes including DNA replication and repair. More than 200 proteins, many involved in stress responses, interact with PCNA through the AlkB homologue 2 PCNA-interacting motif (APIM), including several proteins directly or indirectly involved in repair of DNA interstrand crosslinks (ICLs). In this study, we targeted PCNA with a novel peptide drug containing the APIM sequence, ATX-101, to inhibit repair of the DNA damage introduced by the chemotherapeutics. A bladder cancer cell panel and two different orthotopic models of bladder cancer in rats, the AY-27 implantation model and the dietary BBN induction model, were applied. ATX-101 increased the anticancer efficacy of the ICL-inducing drug mitomycin C (MMC), as well as bleomycin and gemcitabine in all bladder cancer cell lines tested. Furthermore, we found that ATX-101 given intravesically in combination with MMC penetrated the bladder wall and further reduced the tumor growth in both the slow growing endogenously induced and the rapidly growing transplanted tumors. These results suggest that ATX-101 has the potential to improve the efficacy of current MMC treatment in NMIBC.