Bortezomib and Topotecan Hydrochloride in Treating Patients With Advanced Solid Tumors

RATIONALE: Bortezomib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. Drugs used in chemotherapy, such as topotecan hydrochloride, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving bortezomib together with topotecan hydrochloride may kill more tumor cells. PURPOSE: This phase I trial is studying the side effects and best dose of topotecan hydrochloride when given together with bortezomib in treating patients with advanced solid tumors.