CMCC 1579

Prosaposin, a novel anti-metastatic candidate therapeutic and diagnostic

Inventors: Randolph Watnick

Categories: Diagnostic/Prognostic, Therapeutics

SubCategories: Oncology/Hematology

Keywords: Anti-angiogenesis

Invention Description:

Metastasis accounts for 90% of deaths in cancer patients. Randolph Watnick, PhD, has isolated a protein called prosaposin (Psap) that makes distant organs refractory to metastases by causing the production of factors that block the growth of blood vessels. When Dr. Watnick injected mice with Psap-expressing tumor cells known to be highly metastatic, lung metastases were reduced by 80%, lymph node metastases were completely eliminated, and survival time was significantly increased compared to mice injected with the parental cells. When mice were treated with Psap directly before they received an injection of tumor cells, they exhibited 15-fold fewer lung metastates versus vehicle. Moreover, Psap expression was 40% lower in metastatic prostate cancer patients relative to patients with localised primary tumors, and patients with high prosaposin levels had significantly longer survival times.

This project is a recipient of a Technology Development Fund award which will focus on demonstrating the efficacy of prosaposin and its derivatives against tumor growth.

Applications:

Psap could be added to standard cancer therapies to repress metastases or slow their growth. Further studies investigating the potential of this protein to reduce primary tumor size are underway. These findings also indicate that Psap levels could translate into a companion diagnostic test. In addition, Dr. Watnick has developed a powerful screening system to identify other proteins that make tumors refractory to metastasis.

Competitive Advantages:

There is no approved therapy for inhibiting or treating metastases. Additional advantages of Psap are: • Expected to be safe: found at near therapeutic concentrations in breast milk. • Targets tumor stroma rather than cell-autonomous pathways: complementary to VEGF-based and new therapies. • Stromal cells less likely to mutate and develop resistance compared with tumor cells. • Targets pathological and not physiological angiogenesis. • Potent anti-metastatic effect. • Offers systemic protection throughout body against metastasis while likely conferring reduction in primary tumor size (easier to achieve clinical endpoint than metastasis) • Known to be stable in solution: found in serum throughout the body in normal individuals • Serves as an intrinsic biomarker to stratify patient population for efficacy. • Target is well understood and there are existing assays to confirm receptor activity.

Business Opportunity:

Exclusive License

Key Publications: Kang et al., PNAS, July 21 2009, vol. 106, no. 29: 12115-12120.

IPStatus: Pat. Pend.