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Background The cyanogenic diglucoside, amygdalin, has gained high popularity among cancer patients together with, or in place of, conventional therapy. Still, evidence based research on amygdalin is sparse and its benefit controversial. Purpose Since so many cancer patients consume amygdalin, and many clinicians administer it without clear knowledge of its mode of action, current knowledge has been summarized and the pros and cons of its use weighed. Methods A retrospective analysis was conducted for amygdalin relevant reports using the PubMed database with the main search term “Amygdalin” or “laetrile”, at times combined with “cancer”, “patient”, “cyanide” or “toxic”. We did not exclude any “unwanted” articles. Additionally, internet sources authorized by governmental or national institutions have also been included. Sections Individual chapters summarize pharmacokinetics, preclinical and clinical studies and toxicity. Conclusion No convincing evidence showing that amygdalin induces rapid, distinct tumor regression in cancer patients, particularly in those with late-stage disease, is apparent. However, there is also no evidence that purified amygdalin, administered in "therapeutic" dosage, causes toxicity. Multiple aspects of amygdalin administration have not yet been adequately explored, making further investigation necessary to evaluate its actual therapeutic potential.

Aims Despite impressive survival benefits from new agents to treat metastasized prostate cancer (PCa), progressive drug resistance hinders long-term response and restricts the efficacy of subsequent therapy. Due to reported antitumor activity of amygdalin and growing popularity for complementary and alternative medicine the potential of this natural, widely used substance to exert antineoplastic effects on prostate cancer cells has been assessed. Main methods LNCaP (castration-sensitive), DU-145 and PC3 cells (castration-resistant) were exposed to different concentrations of amygdalin for 24 h or 2 weeks. Cell growth was measured by the MTT test, clonal formation by the clonogenic assay. Flow cytometry served to investigate apoptosis and cell cycle phases. Cell cycle regulating proteins and the mTOR–akt signaling axis were analyzed by western blotting. Key findings Amygdalin dose-dependently diminished tumor cell growth with maximum effects at 10 mg/ml. Apoptosis of PC3 and LNCaP but not of DU-145 cells was reduced, whereas colony formation was suppressed in all cell lines. A decrease in the number of G2/M- and S-phase cells along with an elevated number of G0/G1-phase cells was recorded. The cell cycle proteins cdk 1, cdk 2 and cdk 4 as well as cyclin A, cyclin B and cyclin D3 were modulated by amygdalin after both 24 h and 2 weeks. Distinct effects on p19 and p27 expression and on Akt, Rictor and Raptor activation became evident only after 2 weeks. Significance Amygdalin exhibits significant antitumor activity in both castration-sensitive and castration-resistant PCa cell lines and merits further evaluation for therapeutic purposes.

Inhibitors of the mammalian target of rapamycin (mTOR) have improved the treatment of renal cell carcinoma (RCC). However, chronic drug exposure may trigger resistance, limiting the utility of these agents. The metastatic behavior of RCC cells, susceptible (RCCpar) or resistant (RCCres) to the mTOR inhibitor temsirolimus, was investigated. Adhesion to vascular endothelium or immobilized collagen and fibronectin was quantified. Chemotactic motility was evaluated with a modified Boyden chamber assay. Integrin α and β subtype receptors were analyzed by flow cytometry and Western blot analysis. The physiological relevance of the integrins was then determined by blocking studies and small interfering RNA knockdown. Adhesion to endothelial cells and to fibronectin (not to collagen) and chemotaxis were enhanced in RCCres compared to RCCpar. RCCres detached from fibronectin and motile activity further increased under retreatment with low-dosed temsirolimus. α5 integrin was diminished inside the cell and at the cell surface, whereas the β3 subtype was reduced intracellularly but elevated at the plasma membrane. In RCCpar, blocking α5 surface receptors enhanced RCC-collagen but reduced RCC-fibronectin interaction, whereas the opposite was true for RCCres. Chemotaxis of RCCpar but not of RCCres was strongly diminished by the α5 antibody. Blocking β3 significantly lowered chemotaxis with stronger effects on RCCres, compared to RCCpar. Importantly, β3 knockdown reduced chemotaxis of RCCpar but upregulated the motile behavior of RCCres. Temsirolimus resistance is characterized by quantitative alterations of integrin α5 and β3 expression, coupled to functional changes of the integrin molecules, and forces a switch from RCC adhesion to RCC migration.

The growth potential of PC3 prostate cancer cells, sensible (PC3(par)) or resistant (PC3(res)) to the mTOR inhibitor everolimus (RAD001) was investigated. Cell growth and proliferation of PC3(res) was similar to that of PC3(par), and late apoptosis increased in PC3(par) but decreased in PC3(res) following treatment with low dosed everolimus. PC3(res) accumulated in the G2/M-phase, accompanied by cdk1, cdk2 and cyclin B elevation. Knocking down cdk1 or cyclin B distinctly blocked the growth activity of PC3(res). One reason for everolimus resistance may be up-regulation of the cdk1-cyclin B complex in prostate cancer cells, leading to enhanced progression towards G2/M.

Introduction The aim of the current study was to explore the clinico-oncological characteristics, and the therapeutic and survival parameters, of renal transplant recipients who developed de novo transitional cell carcinoma (TCC) over a 30-year period at the authors’ center. Methods Retrospective analysis of records from all registered patients who underwent kidney transplantation at the center between November 1979 and January 2010 who developed de novo TCC of the urinary tract. Results From all 2001 patients analyzed during the study period, 21 recipients developed 19 TCCs of the bladder and 6 TCCs of the upper urinary tract. Among bladder TCCs, 13 (68.4%) cases were confined to mucosa (pTa or carcinoma in situ, n = 7) or submucosa (pT1, n = 6) and 6 others (31.6%) infiltrated the detrusor muscle (≥p T2); the grading distribution was 5 cases of G1, 6 of G2 and 8 of G3. All recurrent cases (n = 8) revealed local or systemic progression. The overall and tumor-specific patient survival rates were 80.2%, 54.0% and 30.0% and 84.9%, 67.4% and 58.9% for 1, 5 and 10 years, respectively. Conclusions In the light of the observed increased aggressiveness of TCC in renal transplant recipients, more frequent examinations and possibly more invasive follow-up protocols should be considered for patients with 1 or more risk factors for development of TCC. Urine cytology (including ureteral wash cytology) may be used as a reliable diagnostic tool in these patients. Prophylactic contralateral nephroureterectomy might be an option in patients at high risk.

The impact of the mTOR inhibitor RAD001 combined with the EGFr/VEGFr tyrosine kinase inhibitor AEE788 on prostate tumor cell growth, adhesion and migration was analyzed in vitro. The RAD001-AEE788 combination profoundly reduced tumor-endothelium and tumor-matrix contacts, suppressing cell growth and cell cycle progression. The underlying molecular mode of action depended on the cell phenotype, since cell cycle proteins, integrin subtype expression and integrin dependent signaling were altered in a different manner in PC-3 and DU-145 versus LNCaP prostate cancer cells. Simultaneous targeting of mTOR and VEGFr/EGFr related pathways may offer a novel therapeutic strategy for prostate cancer treatment.

Aims To analyze the combined impact of the histone deacetylase (HDAC) inhibitor valproic acid (VPA) and the mammalian target of rapamycin (mTOR) inhibitor RAD001 on prostate cancer cell growth. Main methods PC-3, DU-145 and LNCaP cells were treated with RAD001, VPA or with an RAD001–VPA combination for 3 or 5 days. Tumor cell growth, cell cycle progression and cell cycle regulating proteins were then investigated by MTT assay, flow cytometry and Western blotting, respectively. Effects of drug treatment on cell signaling pathways were determined. Key findings Separate application of RAD001 or VPA distinctly reduced tumor cell growth and impaired cell cycle progression. Significant additive effects were evoked when both drugs were used in concert. Particularly, the cell cycle regulating proteins cdk1, cdk2, cdk4 and cyclin B were reduced, whereas p21 and p27 were enhanced by the RAD001–VPA combination. Signaling analysis revealed deactivation of EGFr, ERK1/2 and p70S6k. Phosphorylation of Akt was diminished in DU-145 but elevated in PC-3 and LNCaP cells. Significance The RAD001–VPA combination exerted profound antitumor properties on a panel of prostate cancer cell lines. Therefore, simultaneous blockage of HDAC and mTOR related pathways should be considered when designing novel therapeutic strategies for treating prostate carcinoma.

Tumor cells have evolved effective strategies to escape the host immune response. The objective of this study was to determine whether tumor cells can condition endothelial cells in a specific manner to prevent subsequent adhesion of polymorphonuclear neutrophils (PMNs) and/or peripheral blood lymphocytes (PBLs). Human umbilical vein endothelial cells (HUVECs) and UKF-NB-4 neuroblastoma tumor cells were established in coculture on opposite sides of porous transwell filters. After 24 hours with and without HUVEC conditioning, PMNs or PBLs were added to the HUVEC monolayer. Adhesion to conditioned HUVEC versus adhesion to nonconditioned HUVEC was compared. Effects on endothelial CD44v4, CD44v5, CD44v7, intercellular adhesion molecule 1 (ICAM-1), E-selectin, and vascular cell adhesion molecule 1 (VCAM-1) adhesion receptor expression were analyzed by flow cytometry, intracellular signaling proteins of the mitogen-activated protein kinase pathway and protein kinase C (PKC) subtypes quantified by Western blot analysis. Endothelial conditioning led to a distinct reduction in PMN but not in PBL adhesion to HUVEC. CD44 was significantly reduced, whereas ICAM-1, E-selectin, and VCAM-1 were not altered during HUVEC conditioning. Antibody blockade against CD44v4, CD44v5, and CD44v7 inhibited PMN but not PBL binding. The observed effects were caused by direct tumor cell-HUVEC contact because addition of isolated tumor cell membrane fragments but not of soluble cell culture supernatant to HUVEC induced the CD44 receptor loss. PKCα activity was strongly enhanced in conditioned HUVEC. Blocking PKC prevented the reduction in PMN binding, indicating that this protein is involved in PMN adhesion regulation. A novel tumor escape strategy is presented here. Cell contact-dependent adhesion of tumor cells to the vascular wall promotes down-regulation of endothelial CD44 receptor expression, impairing an effective neutrophil attack.