Curcumin induces p73-dependent apoptosis.

<p>(A) Tu212 (left) and H1299 (right) cells were treated with curcumin and expression of p73 and p73β were measured by Western blotting. (B-C) p73 was inactivated in H1299 (B) and 041 (C) cells by dominant negative p73 and apoptosis was measured by annexin V-PE staining. (D) H1299 cells expressing empty vector or dominant negative p73 were treated with curcumin. Whole cell lysates were immunoblotted with PARP and caspase 3 antibodies. For B and C, average results from three independent experiments were plotted with standard deviation as error bars. p values were determined by student t-test. p<0.05 was considered statistically significant.</p

Inhibition of Bcl-2 is required for curcumin-induced apoptosis.

<p>Tu212, A549 and H292 cells were treated with curcumin and expression of Bcl-2 was examined by immunoblotting. (B) 041 and 041 Bcl-2 overexpressing cells were treated with 10 μM of curcumin for 48 h and expression of Bcl-2 was measured. (C) 041 and 041 Bcl-2 overexpressing cells were treated with 10 μM of curcumin for 48 h and apoptosis was measured by annexin V staining. Average results from three independent experiments were plotted with standard deviation as error bars. p value was determined by student t-test. p<0.05 was considered statistically significant.</p

Curcumin induces mitochondria-mediated apoptosis.

<p>(A) Tu212, (B) H1299 and (C) H292 cells were treated with the indicated concentration of curcumin for the indicated times. Whole cell lysates were immunoblotted with PARP and caspase 3 (detects cleaved form only) antibodies. (D) Tu212 cells were treated with 10 μM of curcumin for the indicated times and whole cell lysates were blotted with caspase 9 antibody. (E) Tu212 cells were treated with 10 μM of curcumin for 24h. Cytoplasmic and mitochondrial fractions were separated and immunoblotted with cytochrome <i>c</i> antibody. COX4 (a mitochondrial protein) was used to show efficiency of cell fractionation. Representative data from three independent experiments are shown.</p

Curcumin dose- and time-dependently induces apoptosis of upper aerodigestive tract cancer cells.

<p>Lung cancer cell lines A549, H292, H460, H1299, and SCCHN cell lines Tu212 and 886LN were treated with the indicated concentration of curcumin for 24 and 48 h. Apoptosis was measured by annexin V-PE staining. Average apoptosis from three independent experiments is presented with standard deviation as error bars.</p

Inhibition of p-AKT is required for curcumin-induced apoptosis.

<p>(A) H1299, (B) Tu212 and (C) Tu686 cells were treated with the indicated concentrations of curcumin for the indicated time and expression of p-AKT, AKT and actin were measured by immunoblotting. (D) Tu212 and Tu686 cells were treated with 10 and 15 μM of curcumin, respectively. Expression of AKT mRNA was measured by qPCR. (E) CA-AKT was overexpressed in Tu686 cells and apoptosis was measured. Average results from three independent experiments were plotted with standard deviation as error bars. p value was determined by student t-test. p<0.05 was considered statistically significant.</p

IC₅₀ values of curcumin.

<p>IC₅₀ values of curcumin.</p

Curcumin Induces Apoptosis of Upper Aerodigestive Tract Cancer Cells by Targeting Multiple Pathways

<div><p>Curcumin, a natural compound isolated from the Indian spice "Haldi" or "curry powder", has been used for centuries as a traditional remedy for many ailments. Recently, the potential use of curcumin in cancer prevention and therapy urges studies to uncover the molecular mechanisms associated with its anti-tumor effects. In the current manuscript, we investigated the mechanism of curcumin-induced apoptosis in upper aerodigestive tract cancer cell lines and showed that curcumin-induced apoptosis is mediated by the modulation of multiple pathways such as induction of p73, and inhibition of p-AKT and Bcl-2. Treatment of cells with curcumin induced both p53 and the related protein p73 in head and neck and lung cancer cell lines. Inactivation of p73 by dominant negative p73 significantly protected cells from curcumin-induced apoptosis, whereas ablation of p53 by shRNA had no effect. Curcumin treatment also strongly inhibited p-AKT and Bcl-2 and overexpression of constitutively active AKT or Bcl-2 significantly inhibited curcumin-induced apoptosis. Taken together, our findings suggest that curcumin-induced apoptosis is mediated via activating tumor suppressor p73 and inhibiting p-AKT and Bcl-2.</p></div

Image_3_Blockade of growth hormone receptor signaling by using pegvisomant: A functional therapeutic strategy in hepatocellular carcinoma.tif

Hepatocellular carcinoma (HCC) is an aggressive neoplasm with poor clinical outcome because most patients present at an advanced stage, at which point curative surgical options, such as tumor excision or liver transplantation, are not feasible. Therefore, the majority of HCC patients require systemic therapy. Nonetheless, the currently approved systemic therapies have limited effects, particularly in patients with advanced and resistant disease. Hence, there is a critical need to identify new molecular targets and effective systemic therapies to improve HCC outcome. The liver is a major target of the growth hormone receptor (GHR) signaling, and accumulating evidence suggests that GHR signaling plays an important role in HCC pathogenesis. We tested the hypothesis that GHR could represent a potential therapeutic target in this aggressive neoplasm. We measured GH levels in 767 HCC patients and 200 healthy controls, and then carried out clinicopathological correlation analyses. Moreover, specific inhibition of GHR was performed in vitro using siRNA and pegvisomant (a small peptide that blocks GHR signaling and is currently approved by the FDA to treat acromegaly) and in vivo, also using pegvisomant. GH was significantly elevated in 49.5% of HCC patients, and these patients had a more aggressive disease and poorer clinical outcome (P<0.0001). Blockade of GHR signaling with siRNA or pegvisomant induced substantial inhibitory cellular effects in vitro. In addition, pegvisomant potentiated the effects of sorafenib (P<0.01) and overcame sorafenib resistance (P<0.0001) in vivo. Mechanistically, pegvisomant decreased the phosphorylation of GHR downstream survival proteins including JAK2, STAT3, STAT5, IRS-1, AKT, ERK, and IGF-IR. In two patients with advanced-stage HCC and high GH who developed sorafenib resistance, pegvisomant caused tumor stability. Our data show that GHR signaling represents a novel “druggable” target, and pegvisomant may function as an effective systemic therapy in HCC. Our findings could also lead to testing GHR inhibition in other aggressive cancers.</p

Image_1_Blockade of growth hormone receptor signaling by using pegvisomant: A functional therapeutic strategy in hepatocellular carcinoma.tif

Hepatocellular carcinoma (HCC) is an aggressive neoplasm with poor clinical outcome because most patients present at an advanced stage, at which point curative surgical options, such as tumor excision or liver transplantation, are not feasible. Therefore, the majority of HCC patients require systemic therapy. Nonetheless, the currently approved systemic therapies have limited effects, particularly in patients with advanced and resistant disease. Hence, there is a critical need to identify new molecular targets and effective systemic therapies to improve HCC outcome. The liver is a major target of the growth hormone receptor (GHR) signaling, and accumulating evidence suggests that GHR signaling plays an important role in HCC pathogenesis. We tested the hypothesis that GHR could represent a potential therapeutic target in this aggressive neoplasm. We measured GH levels in 767 HCC patients and 200 healthy controls, and then carried out clinicopathological correlation analyses. Moreover, specific inhibition of GHR was performed in vitro using siRNA and pegvisomant (a small peptide that blocks GHR signaling and is currently approved by the FDA to treat acromegaly) and in vivo, also using pegvisomant. GH was significantly elevated in 49.5% of HCC patients, and these patients had a more aggressive disease and poorer clinical outcome (P<0.0001). Blockade of GHR signaling with siRNA or pegvisomant induced substantial inhibitory cellular effects in vitro. In addition, pegvisomant potentiated the effects of sorafenib (P<0.01) and overcame sorafenib resistance (P<0.0001) in vivo. Mechanistically, pegvisomant decreased the phosphorylation of GHR downstream survival proteins including JAK2, STAT3, STAT5, IRS-1, AKT, ERK, and IGF-IR. In two patients with advanced-stage HCC and high GH who developed sorafenib resistance, pegvisomant caused tumor stability. Our data show that GHR signaling represents a novel “druggable” target, and pegvisomant may function as an effective systemic therapy in HCC. Our findings could also lead to testing GHR inhibition in other aggressive cancers.</p

Image_4_Blockade of growth hormone receptor signaling by using pegvisomant: A functional therapeutic strategy in hepatocellular carcinoma.tif

Hepatocellular carcinoma (HCC) is an aggressive neoplasm with poor clinical outcome because most patients present at an advanced stage, at which point curative surgical options, such as tumor excision or liver transplantation, are not feasible. Therefore, the majority of HCC patients require systemic therapy. Nonetheless, the currently approved systemic therapies have limited effects, particularly in patients with advanced and resistant disease. Hence, there is a critical need to identify new molecular targets and effective systemic therapies to improve HCC outcome. The liver is a major target of the growth hormone receptor (GHR) signaling, and accumulating evidence suggests that GHR signaling plays an important role in HCC pathogenesis. We tested the hypothesis that GHR could represent a potential therapeutic target in this aggressive neoplasm. We measured GH levels in 767 HCC patients and 200 healthy controls, and then carried out clinicopathological correlation analyses. Moreover, specific inhibition of GHR was performed in vitro using siRNA and pegvisomant (a small peptide that blocks GHR signaling and is currently approved by the FDA to treat acromegaly) and in vivo, also using pegvisomant. GH was significantly elevated in 49.5% of HCC patients, and these patients had a more aggressive disease and poorer clinical outcome (P<0.0001). Blockade of GHR signaling with siRNA or pegvisomant induced substantial inhibitory cellular effects in vitro. In addition, pegvisomant potentiated the effects of sorafenib (P<0.01) and overcame sorafenib resistance (P<0.0001) in vivo. Mechanistically, pegvisomant decreased the phosphorylation of GHR downstream survival proteins including JAK2, STAT3, STAT5, IRS-1, AKT, ERK, and IGF-IR. In two patients with advanced-stage HCC and high GH who developed sorafenib resistance, pegvisomant caused tumor stability. Our data show that GHR signaling represents a novel “druggable” target, and pegvisomant may function as an effective systemic therapy in HCC. Our findings could also lead to testing GHR inhibition in other aggressive cancers.</p