To improve prognosis in recurrent glioblastoma we developed a treatment protocol based on a combination of drugs not traditionally thought of as cytotoxic chemotherapy agents but that have a robust history of being well-tolerated and are already marketed and used for other non-cancer indications. Focus was on adding drugs which met these criteria: a) were pharmacologically well characterized, b) had low likelihood of adding to patient side effect burden, c) had evidence for interfering with a recognized, well-characterized growth promoting element of glioblastoma, and d) were coordinated, as an ensemble had reasonable likelihood of concerted activity against key biological features of glioblastoma growth. We found nine drugs meeting these criteria and propose adding them to continuous low dose temozolomide, a currently accepted treatment for relapsed glioblastoma, in patients with recurrent disease after primary treatment with the Stupp Protocol. The nine adjuvant drug regimen, Coordinated Undermining of Survival Paths, CUSP9, then are aprepitant, artesunate, auranofin, captopril, copper gluconate, disulfiram, ketoconazole, nelfinavir, sertraline, to be added to continuous low dose temozolomide. We discuss each drug in turn and the specific rationale for use- how each drug is expected to retard glioblastoma growth and undermine glioblastoma's compensatory mechanisms engaged during temozolomide treatment. The risks of pharmacological interactions and why we believe this drug mix will increase both quality of life and overall survival are reviewed.

Endoplasmic reticulum (ER) stress and autophagy are two basic cell survival mechanisms often occurring in concert. Extensive ER stress in cancer cells deliberately induced by chemotherapeutic drugs may lead to growth arrest and cell death. However, the link between ER stress and autophagy is not well understood. In this study, the treatment of cancer cells with ER stress-inducing drug nelfinavir resulted in the expression of endogenous mTOR inhibitor sestrin-2 (SESN2). Upregulation of SESN2 expression was associated with expression of ER stress markers ATF4, ATF3, and CHOP. SESN2 upregulation also occurred in cells treated with the proteasome inhibitor bortezomib. Ectopic expression of ATF4, but not of ATF3 or CHOP, caused transcriptional upregulation of SESN2 expression, indicating expressional regulation of SESN2 by ATF4. Transient overexpression of ectopic SESN2 resulted in mTOR inhibition and autophagy, confirming a link between ER stress, SESN2 upregulation, and mTOR inhibition. Accordingly, cancer cells treated with the ER stress-inducing agent nelfinavir showed reduced mTOR activity and associated increases in the expression levels of ATF4 and SESN2. These results show that ATF4-regulated SESN2 expression presents a new link between ER stress and mTOR inhibition and autophagy. mTOR inhibition by nelfinavir, which is currently in clinical trials for cancer patients, may also explain its observed ability to induce autophagy, growth arrest, and radiosensitization in cancer cells.

The metastasis-associated genes MTA1 and MTA3 are transcriptional repressors with potential effects on cancer. We analyzed the expression of MTA1, MTA3, ERalpha, ERbeta and E-cadherin in a total of 115 paraffin-embedded ovarian cancer tissues with respect to cancer staging and FIGO grading. Expression of MTA1, but not that of MTA3, was found to be significantly enhanced in ovarian cancer tissues with advanced cancer stages and higher FIGO grading, indicating an important role of MTA1 in the progression of ovarian cancer. To get further insights into the function of MTA1 in ovarian cancer, MTA1-overexpressing cancer cell clones were generated. In vitro, overexpression of exogenous MTA1 in OVCAR-3 cells had no effect on cell proliferation but enhanced the ability of anchorage-independent growth in soft agar colony formation assays. MTA1 overexpression resulted in downregulation of E-cadherin and MTA3 expression and enhanced expression of the transcriptional repressors SNAIL and SLUG. MTA1 further reduced ERbeta expression in vitro and inversely correlated with ERbeta expression in vivo. Screening for the expression of angiogenic cytokines expressed by ovarian cancer cells revealed MTA1-mediated upregulation of the oncogenic and angiogenic cytokine GRO (growth-regulated oncogene, CXCL1). Thus, in ovarian cancer, MTA1 expression directly and indirectly regulates the expression of several cancer-promoting as well as metastasis-facilitating factors, indicating an important role for MTA1 expression during ovarian cancer progression.

Immunohistochemical analysis of ER might be used as an easy, simple and highly efficient marker to identify high-risk patients and may aid in the selection of patients for a more aggressive adjuvant therapy. Furthermore, patients that show a positive ER-alpha immunostaining can be selected for a specific anti-hormonal therapy, as already performed for breast cancer patients.

Quercetin is an abundant micronutrient in our daily diet. Several beneficial health effects are associated with the dietary uptake of this bioflavonoid, including alleviating effects on chronic inflammation and atherosclerosis. A variety of in vitro data indicate a possible use of quercetin for cancer treatment purposes through its interaction with multiple cancer-related pathways. Among these, recent data reveal that quercetin can inhibit mTOR activity in cancer cells. Inhibition of the mTOR signaling pathway by quercetin has directly been described and can further be deduced from its interference with PI3K-dependent Akt stimulation, AMP-dependent protein kinase activation and hamartin upregulation. The ability of quercetin to interfere with both mTOR activity and activation of the PI3K/Akt signaling pathway gives quercetin the advantage to function as a dual-specific mTOR/PI3K inhibitor. The mTOR complex, often hyperactivated in cancer, is a crucial regulator of homeostasis controlling essential pathways leading to cell growth, protein biosynthesis and autophagy. The ability of quercetin to inhibit mTOR activity by multiple pathways makes this otherwise safe bioflavonoid an interesting tool for the treatment of cancers and other diseases associated with mTOR deregulation.