Christos N. Papandreou

Phase I Trial of the Proteasome Inhibitor Bortezomib in Patients With Advanced Solid Tumors With Observations in Androgen-Independent Prostate Cancer

PURPOSE To determine the dose-limiting toxicity and maximum-tolerated dose of the proteasome inhibitor bortezomib administered intravenously weekly for 4 every 5 weeks; to determine the bortezomib pharmacokinetics and pharmacodynamics using plasma levels and an assay for 20S proteasome inhibition (PI) in whole blood; to correlate toxicity with bortezomib dose and degree of 20S PI; and to conduct a preliminary determination of the antitumor activity of bortezomib in patients with androgen independent prostate cancer (AIPCa). PATIENTS AND METHODS Fifty-three patients (48 with AIPCa) received 128 cycles of bortezomib in doses ranging from 0.13 to 2.0 mg/m(2)/dose, utilizing a careful escalation scheme with a continuous reassessment method. Pharmacokinetic and pharmacodynamic studies were performed in 24 patients (at 1.45 to 2.0 mg/m(2)). RESULTS A dose-related 20S PI was seen, with dose-limiting toxicity at 2.0 mg/m(2) (diarrhea, hypotension) occurring at an average 1-hour post-dose of >/= 75% 20S PI. Other side effects were fatigue, hypertension, constipation, nausea, and vomiting. No relationship was seen between body-surface area and bortezomib clearance over the narrow dose range tested. There was evidence of biologic activity (decline in serum prostate-specific antigen and interleukin-6 levels) at >/= 50% 20S PI. Two patients with AIPCa had prostate-specific antigen response and two patients had partial response in lymph nodes. CONCLUSION The maximum-tolerated dose and recommended phase II dose of bortezomib in this schedule is 1.6 mg/m(2). Biologic activity (inhibition of nuclear factor-kappa B-related markers) and antitumor activity is seen in AIPCa at tolerated doses of bortezomib. This agent should be further explored with chemotherapy agents in advanced prostate cancer.

Bone-targeted therapy for advanced androgen-independent carcinoma of the prostate: a randomised phase II trial

BACKGROUND Prostate carcinoma is linked to osteoblastic metastasis. We therefore investigated the value of bone-targeted consolidation therapy in selected patients with advanced androgen-independent carcinoma of the prostate. METHODS 103 patients received induction chemotherapy, consisting of ketoconazole and doxorubicin alternating with estramustine and vinblastine. After two or three cycles of induction chemotherapy, we randomly assigned 72 patients who were clinically stable or responders to receive doxorubicin with or without strontium-89 (Sr-89) every week for 6 weeks. FINDINGS Overall 62 of the 103 (60%, 95% CI 50-70) patients had a 50% or greater reduction in serum prostate-specific antigen concentration that was maintained for at least 8 weeks, and 43 (42%, 32-52) had an 80% or greater reduction. 49 (52%) patients with bone pain at registration had complete resolution of pain. After follow-up of 67 patients until death, the estimated median survival for all 103 patients was 17.5 months (range 0.5-37.7). For the 36 patients randomly assigned to receive Sr-89 and doxorubicin, the median survival time was 27.7 months (4.9-37.7), and for the 36 who received doxorubicin alone it was 16.8 months (4.4-34.2) (p=0.0014). The hazard ratio was 2.76 (95% CI 1.44-5.29). INTERPRETATION Bone-targeted consolidation therapy consisting of one dose of Sr-89 plus doxorubicin once a week for 6 weeks, when given to patients with stable or responding advanced androgen-independent carcinoma of the prostate after induction chemotherapy, improved overall survival.

Neutral endopeptidase 24.11 loss in metastatic human prostate cancer contributes to androgen-independent progression

Neutral endopeptidase 24.11 (NEP) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate cancer (PC). We report that NEP expression and catalytic activity are lost in vitro in androgen-independent but not androgen-dependent PC cell lines. In vivo, NEP protein expression is commonly decreased in cancer cells of metastatic PC specimens from patients with androgen-independent but not androgen-dependent PC. Overexpression of NEP in androgen-independent PC cells or incubation with recombinant NEP inhibits PC cell growth. Furthermore, in androgen-dependent PC cells, expression of NEP is transcriptionally regulated by androgen and decreases with androgen withdrawal. These data suggest that decreased NEP expression, common in androgen-independent PCs, is facilitated by the elimination of androgens, and that NEP loss plays an important role in the development of androgen-independent PC by allowing PC cells to use mitogenic neuropeptides as an alternate source to androgen in order to stimulate cell proliferation.

Results of a Phase II Study With Doxorubicin, Etoposide, and Cisplatin in Patients With Fully Characterized Small-Cell Carcinoma of the Prostate

PURPOSE To determine the activity and toxicity of doxorubicin in combination with cisplatin and etoposide in patients with small-cell prostate carcinoma (SCPCa) and to characterize the clinicopathologic features of SCPCa. PATIENTS AND METHODS Patients with SCPCa (pure or mixed), measurable disease, good organ function, and no prior treatment with doxorubicin, etoposide, or cisplatin were treated every 4 weeks with doxorubicin 50 mg/m(2) as a 24-hour intravenous (IV) infusion followed by etoposide 120 mg/m(2)/d and cisplatin 25 mg/m(2)/d IV on days 2 to 4. RESULTS Thirty-eight patients (36 assessable for response) were treated for a median of four cycles. Twenty-nine (81%) of 36 patients had prior hormonal therapy. Study patients had visceral metastases, lytic bone disease, and relatively low serum prostate-specific antigen (PSA). We observed 22 partial responses (response rate, 61% in an intent-to-treat analysis); toxicity was severe (grade 3 or 4 neutropenia 100%, thrombocytopenia 66%, mucositis 21%, and infection 68%). Three patients died of toxicity. Median time to progression and overall survival time were 5.8 months and 10.5 months, respectively. Performance status, serum albumin, and number of organs involved (but not PSA, carcinoembryonic antigen, or neuroendocrine markers) were predictors of survival. CONCLUSION SCPCa presents unique clinicopathologic features. Addition of doxorubicin to the etoposide/cisplatin regimen caused higher toxicity in this patient population and failed to improve outcome. Given these results, we do not recommend further development of this regimen for patients with SCPCa. Improvement in therapy will come from understanding the biology of SCPCa progression and integrating new targeted therapies into the treatment of SCPCa.

Neutral endopeptidase inhibits prostate cancer cell migration by blocking focal adhesion kinase signaling

Neutral endopeptidase 24.11 (NEP, CD10) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate cancer (PC). NEP substrates such as bombesin and endothelin-1 induce cell migration. We investigated the mechanisms of NEP regulation of cell migration in PC cells, including regulation of phosphorylation on tyrosine of focal adhesion kinase (FAK). Western analyses and cell migration assays revealed an inverse correlation between NEP expression and the levels of FAK phosphorylation and cell migration in PC cell lines. Constitutively expressed NEP, recombinant NEP, and induced NEP expression using a tetracycline-repressive expression system inhibited bombesin- and endothelin-1-stimulated FAK phosphorylation and cell migration. This results from NEP-induced inhibition of neuropeptide-stimulated association of FAK with cSrc protein. Expression of a mutated catalytically inactive NEP protein also resulted in partial inhibition of FAK phosphorylation and cell migration. Coimmunoprecipitation experiments show that NEP associates with tyrosine-phosphorylated Lyn kinase, which then binds the p85 subunit of phosphatidylinositol 3-kinase (PI3-K) resulting in an NEP-Lyn-PI3-K protein complex. This complex competitively blocks FAK-PI3-K interaction, suggesting that NEP protein inhibits cell migration via a protein-protein interaction independent of its catalytic function. These experiments demonstrate that NEP can inhibit FAK phosphorylation on tyrosine and PC cell migration through multiple pathways and suggest that cell migration which contributes to invasion and metastases in PC cells can be regulated by NEP.

GIDEON (Global Investigation of therapeutic DEcisions in hepatocellular carcinoma and Of its treatment with sorafeNib): second interim analysis

GIDEON (Global Investigation of therapeutic DEcisions in hepatocellular carcinoma [HCC] and Of its treatment with sorafeNib) is a global, prospective, non‐interventional study undertaken to evaluate the safety of sorafenib in patients with unresectable HCC in real‐life practice, including Child‐Pugh B patients who were excluded from clinical trials.

Bortezomib as a Potential Treatment for Prostate Cancer

Androgen ablation and chemotherapy provide effective palliation for most patients with advanced prostate cancer, but eventually progressing androgen-independent prostate cancer threatens the lives of patients usually within a few years, mandating improvement in therapy. Proteasome inhibition has been proposed as a therapy target for the treatment of solid and hematological malignancies. The proteasome is a ubiquitous enzyme complex that is a hub for the regulation of many intracellular regulatory pathways; because of its essential function, this enzyme has become a new target for cancer treatment. Studies with bortezomib (VELCADE, formerly known as PS-341) and other proteasome inhibitors indicate that cancer cells are especially dependent on the proteasome for survival, and several mechanisms used by prostate cancer cells require proteasome function. Bortezomib has been studied extensively in vitro and in vivo, and anticancer activity has been seen in cell and animal models for several solid tumor types, including prostate cancer. A Phase I trial to determine the maximum tolerated dose of once-weekly bortezomib has been completed. This trial included a large fraction of patients with androgen-independent prostate cancer. The maximum tolerated dose was reached at 1.6 mg/m2. A correlation was seen among bortezomib dose, proteasome inhibition, and positive modulation of serum prostate-specific antigen. There was also evidence of down-regulation of serum interleukin 6, a downstream nuclear factor κB effector. This Phase I trial and preclinical studies support additional testing of bortezomib in combination with radiation or chemotherapy for androgen-independent prostate cancer.

First interim analysis of the GIDEON (Global Investigation of therapeutic decisions in hepatocellular carcinoma and of its treatment with sorafeNib) non-interventional study.

Aims:  Global Investigation of therapeutic DEcisions in hepatocellular carcinoma and Of its treatment with sorafeNib (GIDEON), a global, non‐interventional, surveillance study, aims to evaluate the safety of sorafenib in all patients with unresectable hepatocellular carcinoma (uHCC) under real‐life practice conditions, particularly Child‐Pugh B patients, who were not well represented in clinical trials.

A pilot study of thalidomide in patients with progressive metastatic renal cell carcinoma.

The highly vascular nature of renal cell carcinoma (RCC) suggests that angiogenesis inhibition may be therapeutic for patients with this disease. Thalidomide inhibits basic fibroblast growth factor and vascular endothelial growth factor (VEGF)‐induced angiogenesis.

Erratum to: Bortezomib represses HIF-1α protein expression and nuclear accumulation by inhibiting both PI3K/Akt/TOR and MAPK pathways in prostate cancer cells

Bortezomib represents the first proteasome inhibitor (PI) with demonstrated antitumor activity in the clinical setting, particularly for treatment of hematological malignancies. At the preclinical level, its action is shown to be mediated by induction of growth arrest and apoptosis in many tumor types, including androgen-dependent (AD) and androgen-independent (AI) prostate cancer (PCa) cells. Hypoxia-inducible factor-1α (HIF-1α), which is directly involved in tumor growth, is one of the most studied and promising molecular targets for anti-cancer therapy and is often overexpressed in PCa. Bortezomib has been reported to impair tumor growth by also inhibiting HIF-1α. In this study, we investigated the effect of bortezomib on the expression, activity and localization of HIF-1α in LNCaP (AD) and PC3 (AI) PCa cells. First, we show that hypoxic upregulation of HIF-1α protein levels and activity involves both the PI3K/Akt/mTOR and p44/42 MAPK pathways. Second, bortezomib inhibits expression of HIF-1α protein under both normoxic and hypoxic conditions, represses HIF-1 transcriptional activity and attenuates the release of vascular endothelial growth factor. These effects correlate with the ability of bortezomib to cause dephosphorylation of phospho-Akt, phospho-p70S6K, and phospho-S6RP, thus inactivating a pathway known to be required for HIF-1α protein expression at the translational level. Furthermore, bortezomib also abrogates p44/42 MAPK phosphorylation, which results to reduced nuclear translocation of HIF-1α. Taken together, these results suggest that bortezomib inhibits HIF-1α protein synthesis and its nuclear targeting through suppression of PI3K/Akt/mTOR and MAPK pathways, respectively, in both AD and AI PCa cells.