Excell Partners, a Rochester-based venture capital fund, is investing in a Buffalo-based company working on technology that could help develop drugs targeting prostate cancer. The company, AndroBioSys Inc., grew out of research done at Roswell Park Cancer Institute. The company also is receiving assistance from the Erie County Industrial Development Agency and a group of investors from the Western N.Y. Venture Association. Excell would not say how much it invested in the Buffalo company, but its funding allocations are up to $250,000 per company. The 4-year-old nonprofit Excell is a collaboration between the state and University of Rochester.