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Bladder cancer patients whose tumors develop resistance to cisplatin-based chemotherapy often turn to natural, plant-derived products. Beneficial effects have been particularly ascribed to polyphenols, although their therapeutic relevance when resistance has developed is not clear. The present study evaluated the anti-tumor potential of polyphenol-rich olive mill wastewater (OMWW) on chemo-sensitive and cisplatin- and gemcitabine-resistant T24, RT112, and TCCSUP bladder cancer cells in vitro. The cells were treated with different dilutions of OMWW, and tumor growth and clone formation were evaluated. Possible mechanisms of action were investigated by evaluating cell cycle phases and cell cycle-regulating proteins. OMWW profoundly inhibited the growth and proliferation of chemo-sensitive as well as gemcitabine- and cisplatin-resistant bladder cancer cells. Depending on the cell line and on gemcitabine- or cisplatin-resistance, OMWW induced cell cycle arrest at different phases. These differing phase arrests were accompanied by differing alterations in the CDK-cyclin axis. Considerable suppression of the Akt-mTOR pathway by OMWW was observed in all three cell lines. Since OMWW blocks the cell cycle through the manipulation of the cyclin-CDK axis and the deactivation of Akt-mTOR signaling, OMWW could become relevant in supporting bladder cancer therapy.
Tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors predominate as first-line therapy options for renal cell carcinoma. When first-line TKI therapy fails due to resistance development, an optimal second-line therapy has not yet been established. The present investigation is directed towards comparing the anti-angiogenic properties of the TKIs, sorafenib and axitinib on human endothelial cells (HUVECs) with acquired resistance towards the TKI sunitinib. HUVECs were driven to resistance by continuously exposing them to sunitinib for six weeks. They were then switched to a 24 h or further six weeks treatment with sorafenib or axitinib. HUVEC growth, as well as angiogenesis (tube formation and scratch wound assay), were evaluated. Cell cycle proteins of the CDK-cyclin axis (CDK1 and 2, total and phosphorylated, cyclin A and B) and the mTOR pathway (AKT, total and phosphorylated) were also assessed. Axitinib (but not sorafenib) significantly suppressed growth of sunitinib-resistant HUVECs when they were exposed for six weeks. This axinitib-associated growth reduction was accompanied by a cell cycle block at the G0/G1-phase. Both axitinib and sorafenib reduced HUVEC tube length and prevented wound closure (sorafenib > axitinib) when applied to sunitinib-resistant HUVECs for six weeks. Protein analysis revealed diminished phosphorylation of CDK1, CDK2 and pAKT, accompanied by a suppression of cyclin A and B. Both drugs modulated CDK-cyclin and AKT-dependent signaling, associated either with both HUVEC growth and angiogenesis (axitinib) or angiogenesis alone (sorafenib). Axitinib and sorafenib may be equally applicable as second line treatment options, following sunitinib resistance.
Although anti-cancer properties of the natural compound curcumin have been reported, low absorption and rapid metabolisation limit clinical use. The present study investigated whether irradiation with visible light may enhance the inhibitory effects of low-dosed curcumin on prostate cancer cell growth, proliferation, and metastasis in vitro. DU145 and PC3 cells were incubated with low-dosed curcumin (0.1–0.4 µg/mL) and subsequently irradiated with 1.65 J/cm2 visible light for 5 min. Controls remained untreated and/or non-irradiated. Cell growth, proliferation, apoptosis, adhesion, and chemotaxis were evaluated, as was cell cycle regulating protein expression (CDK, Cyclins), and integrins of the α- and β-family. Curcumin or light alone did not cause any significant effects on tumor growth, proliferation, or metastasis. However, curcumin combined with light irradiation significantly suppressed tumor growth, adhesion, and migration. Phosphorylation of CDK1 decreased and expression of the counter-receptors cyclin A and B was diminished. Integrin α and β subtypes were also reduced, compared to controls. Irradiation distinctly enhances the anti-tumor potential of curcumin in vitro and may hold promise in treating prostate cancer.
Despite recent advances in the treatment of metastatic prostate cancer (PCa), resistance development after taxane treatments is inevitable, necessitating effective options to combat drug resistance. Previous studies indicated antitumoral properties of the natural compound amygdalin. However, whether amygdalin acts on drug-resistant tumor cells remains questionable. An in vitro study was performed to investigate the influence of amygdalin (10 mg/mL) on the growth of a panel of therapy-naïve and docetaxel- or cabazitaxel-resistant PCa cell lines (PC3, DU145, and LNCaP cells). Tumor growth, proliferation, clonal growth, and cell cycle progression were investigated. The cell cycle regulating proteins (phospho)cdk1, (phospho)cdk2, cyclin A, cyclin B, p21, and p27 and the mammalian target of rapamycin (mTOR) pathway proteins (phospho)Akt, (phospho)Raptor, and (phospho)Rictor as well as integrin β1 and the cytoskeletal proteins vimentin, ezrin, talin, and cytokeratin 8/18 were assessed. Furthermore, chemotactic activity and adhesion to extracellular matrix components were analyzed. Amygdalin dose-dependently inhibited tumor growth and reduced tumor clones in all (parental and resistant) PCa cell lines, accompanied by a G0/G1 phase accumulation. Cell cycle regulating proteins were significantly altered by amygdalin. A moderate influence of amygdalin on tumor cell adhesion and chemotaxis was observed as well, paralleled by modifications of cytoskeletal proteins and the integrin β1 expression level. Amygdalin may, therefore, block tumor growth and disseminative characteristics of taxane-resistant PCa cells. Further studies are warranted to determine amygdalin’s value as an antitumor drug.
Highlights
• Out of the six edible pumpkin seeds found in Cameroonian C. sativus showed most potent anti-proliferative effects on prostate cells.
• Its oil conserved almost all the effects of raw seeds and prevented benign prostatic hyperplasia (BPH).
• It exhibited potent anti-inflammatory activities in rat with BPH.
Abstract
Pumpkin seeds are claimed to treat prostate tumour/cancer. The in vitro (ability to inhibit cell growth through MTT assay) and in vivo (ability to prevent testosterone-induced BPH in rats at the doses of 125, 250, 500 and 1000 mg/kg BW) of six edible pumpkin seeds found in Cameroonian were assessed. The endpoints were cell growth arrest, prostate mass and volume, prostatic epithelium height, prostatic proteins, prostate specific antigen (PSA) and inflammatory cytokines. In vitro, C. sativus seeds exhibited the most potent antiproliferative effects on DU145 and PC3 prostate cancer cells and its oil conserved almost all the effects of raw seeds. Further, it prevented the increased of prostate relative mass and volume, prostate epithelium height, PSA and testosterone dose-dependently compared to normal rats. This effect is thought to be mediated through antiandrogenic, estrogenic and anti-inflammatory activities, evidenced by a decreased in IL-1β, IL-6 and TNFα level. Overall, this results justify its traditional use.
Prostate cancer patients whose tumors develop resistance to conventional treatment often turn to natural, plant-derived products, one of which is sulforaphane (SFN). This study was designed to determine whether anti-tumor properties of SFN, identified in other tumor entities, are also evident in cultivated DU145 and PC3 prostate cancer cells. The cells were incubated with SFN (1–20 µM) and tumor cell growth and proliferative activity were evaluated. Having found a considerable anti-growth, anti-proliferative, and anti-clonogenic influence of SFN on both prostate cancer cell lines, further investigation into possible mechanisms of action were performed by evaluating the cell cycle phases and cell-cycle-regulating proteins. SFN induced a cell cycle arrest at the S- and G2/M-phase in both DU145 and PC3 cells. Elevation of histone H3 and H4 acetylation was also evident in both cell lines following SFN exposure. However, alterations occurring in the Cdk-cyclin axis, modification of the p19 and p27 proteins and changes in CD44v4, v5, and v7 expression because of SFN exposure differed in the two cell lines. SFN, therefore, does exert anti-tumor properties on these two prostate cancer cell lines by histone acetylation and altering the intracellular signaling cascade, but not through the same molecular mechanisms.