Changhua Zhang

Comparative benefits of Nab-paclitaxel over gemcitabine or polysorbate-based docetaxel in experimental pancreatic cancer

Gemcitabine has limited clinical benefits in pancreatic ductal adenocarcinoma. The solvent-based traditional taxanes docetaxel and paclitaxel have not shown clinical results superior to gemcitabine. Nab-paclitaxel, a water-soluble albumin-bound paclitaxel, may carry superior distribution properties into the tumor microenvironment and has shown efficacy in multiple tumor types. We evaluated nab-paclitaxel effects compared with gemcitabine or docetaxel. For pancreatic ductal adenocarcinoma cells AsPC-1, BxPC-3, MIA PaCa-2 and Panc-1, gemcitabine IC50 ranged from 494nM to 23.9 μM; docetaxel IC50 range was from 5 to 34nM; nab-paclitaxel IC50 range was from 243nM to 4.9 μM. Addition of IC25 dose of docetaxel or nab-paclitaxel decreased gemcitabine IC50. Net tumor growth inhibition after gemcitabine, docetaxel or nab-paclitaxel was 67, 31 and 72%, which corresponded with intratumoral proliferative and apoptotic indices. Tumor stromal density was decreased by nab-paclitaxel and to a lesser extent by docetaxel as measured through reduction in α-smooth muscle actin, S100A4 and collagen 1 expression. Animal survival was prolonged after nab-paclitaxel treatment (41 days, P < 0.002) compared with gemcitabine (32 days, P = 0.005), docetaxel (32 days, P = 0.005) and controls (20 days). Survival in nab-paclitaxel/gemcitabine and docetaxel/gemcitabine sequential treatment groups was not superior to nab-paclitaxel alone. Low-dose combination of gemcitabine with nab-paclitaxel or docetaxel was more effective compared with controls or gemcitabine alone but not superior to regular dose nab-paclitaxel alone. Combination treatment of gemcitabine+nab-paclitaxel or gemcitabine+docetaxel increased gemcitabine concentration in plasma and tumor. The superior antitumor activity of nab-paclitaxel provides a strong rationale for considering nab-paclitaxel as first-line monotherapy in pancreatic ductal adenocarcinoma.

BMS-754807, a Small Molecule Inhibitor of Insulin-like Growth Factor-1 Receptor / Insulin Receptor, Enhances Gemcitabine Response in Pancreatic Cancer

Gemcitabine has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). Insulin-like growth factor (IGF) signaling proteins are frequently overexpressed in PDAC. The therapeutic potential of BMS-754807, a small-molecule inhibitor of IGF-type 1 receptor (IGF-1R) and insulin receptor (IR), and gemcitabine was evaluated in experimental PDAC. Cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and survival studies were conducted in murine xenografts. PDAC cells expressed phospho-IGF-1R protein. BMS-754807 and gemcitabine inhibited cell proliferation of PDAC cells; the combination of BMS-754807 with gemcitabine had additive effects. Addition of BMS-754807 decreased gemcitabine IC50 from 9.7 μmol/L to 75 nmol/L for AsPC-1, from 3 μmol/L to 70 nmol/L for Panc-1, from 72 to 16 nmol/L for MIA PaCa-2, and from 28 to 16 nmol/L for BxPC-3 cells. BMS-754807 caused a decrease in phospho-IGF-1R and phospho-AKT proteins in AsPC-1 and Panc-1 cells. BMS-754807 and gemcitabine caused an increase in PARP-1 and caspase-3 cleavage. Net tumor growth inhibition in BMS-754807, gemcitabine, and BMS-754807+gemcitabine groups was 59%, 35%, and 94% as compared with controls. Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. BMS-754807 also caused a decrease in phospho-IGF-1R and phospho-AKT in tumor tissue lysates. Median animal survival (controls: 21 days) with BMS-754807 was 27 days (P = 0.03), with gemcitabine 28 days (P = 0.05), and in the BMS-754807+gemcitabine combination group, 41 days (P = 0.007). The strong antitumor activity of BMS-754807 in experimental PDAC supports the potential of BMS-754807-induced mechanisms for clinical PDAC therapy. Mol Cancer Ther; 11(12); 2644–53. ©2012 AACR.

Evaluation of poly-mechanistic antiangiogenic combinations to enhance cytotoxic therapy response in pancreatic cancer

Gemcitabine (Gem) has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). The present study investigated combinations of gemcitabine with antiangiogenic agents of various mechanisms for PDAC, including bevacizumab (Bev), sunitinib (Su) and EMAP II. Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting. In vivo experiments were performed via murine xenografts. Inhibition of in vitro proliferation of AsPC-1 PDAC cells by gemcitabine (10 µM), bevacizumab (1 mg/ml), sunitinib (10 µM) and EMAP (10 µM) was 35, 22, 81 and 6 percent; combination of gemcitabine with bevacizumab, sunitinib or EMAP had no additive effects. In endothelial HUVECs, gemcitabine, bevacizumab, sunitinib and EMAP caused 70, 41, 86 and 67 percent inhibition, while combination of gemcitabine with bevacizumab, sunitinib or EMAP had additive effects. In WI-38 fibroblasts, gemcitabine, bevacizumab, sunitinib and EMAP caused 79, 58, 80 and 29 percent inhibition, with additive effects in combination as well. Net in vivo tumor growth inhibition in gemcitabine, bevacizumab, sunitinib and EMAP monotherapy was 43, 38, 94 and 46 percent; dual combinations of Gem+Bev, Gem+Su and Gem+EMAP led to 69, 99 and 64 percent inhibition. Combinations of more than one antiangiogenic agent with gemcitabine were generally more effective but not superior to Gem+Su. Intratumoral proliferation, apoptosis and microvessel density findings correlated with tumor growth inhibition data. Median animal survival was increased by gemcitabine (26 days) but not by bevacizumab, sunitinib or EMAP monotherapy compared to controls (19 days). Gemcitabine combinations with bevacizumab, sunitinib or EMAP improved survival to similar extent (36 or 37 days). Combinations of gemcitabine with Bev+EMAP (43 days) or with Bev+Su+EMAP (46 days) led to the maximum survival benefit observed. Combination of antiangiogenic agents improves gemcitabine response, with sunitinib inducing the strongest effect. These findings demonstrate advantages of combining multi-targeting agents with standard gemcitabine therapy for PDAC.

Superior Antitumor Activity of Nanoparticle Albumin-Bound Paclitaxel in Experimental Gastric Cancer

Gastric cancer is the second common cause of cancer related death worldwide and lacks highly effective treatment for advanced disease. Nab-paclitaxel is a novel microtubule-inhibitory cytotoxic agent that has not been tested in gastric cancer as of yet. In this study, human gastric cancer cell lines AGS, NCI-N87 and SNU16 were studied. Nab-paclitaxel inhibited cell proliferation with an IC50 of 5 nM in SNU16, 23 nM in AGS and 49 nM in NCI-N87 cells after 72-hour treatment, which was lower than that of oxaliplatin (1.05 μM to 1.51 μM) and epirubicin (0.12 μM to 0.25 μM). Nab-paclitaxel treatment increased expression of the mitotic-spindle associated phospho-stathmin irrespective of the baseline total or phosphorylated stathmin level, and induced mitotic cell death as confirmed through increased expression of cleaved-PARP and caspase-3. After a two-week nab-paclitaxel, oxaliplatin or epirubicin treatment, the average in vivo local tumor growth inhibition rate was 77, 17.2 and 21.4 percent, respectively (p = 0.002). Effects of therapy on tumoral proliferative and apoptotic indices corresponded with tumor growth inhibition data, while expression of phospho-stathmin also increased in tissues. There was an increase in median animal survival after nab-paclitaxel treatment (93 days) compared to controls (31 days, p = 0.0007), oxaliplatin (40 days, p = 0.0007) or to docetaxel therapy (81 days, p = 0.0416). The strong antitumor activity of nab-paclitaxel in experimental gastric cancer supports such microtubule-inhibitory strategy for clinical application. Nab-paclitaxel benefits were observed independent from phosphorylated stathmin expression at baseline, putting into question the consideration of nab-paclitaxel use in gastric cancer based on this putative biomarker.

Efficacy of adjuvant XELOX and FOLFOX6 chemotherapy after D2 dissection for gastric cancer

AIM To compare the efficacy of capecitabine and oxaliplatin (XELOX) with 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX6) in gastric cancer patients after D2 dissection. METHODS Between May 2004 and June 2010, patients in our gastric cancer database who underwent D2 dissection for gastric cancer at the First Affiliated Hospital of Sun Yat-Sen University were retrospectively analyzed. A total of 896 patients were enrolled into this study according to the established inclusion and exclusion criteria. Of these patients, 214 received the XELOX regimen, 48 received FOLFOX6 therapy and 634 patients underwent surgery only without chemotherapy. Overall survival was compared among the three groups using Cox regression and propensity score matched-pair analyses. RESULTS Patients in the XELOX and FOLFOX6 groups were younger at the time of treatment (median age 55.2 years; 51.2 years vs 58.9 years), had more undifferentiated tumors (70.1%; 70.8% vs 61.4%), and more lymph node metastases (80.8%; 83.3% vs 57.7%), respectively. Overall 5-year survival was 57.3% in the XELOX group which was higher than that (47.5%) in the surgery only group (P = 0.062) and that (34.5%) in the FOLFOX6 group (P = 0.022). Multivariate analysis showed that XELOX therapy was an independent prognostic factor (hazard ratio = 0.564, P < 0.001). After propensity score adjustment, XELOX significantly increased overall 5-year survival compared to surgery only (58.2% vs 44.2%, P = 0.025) but not compared to FOLFOX6 therapy (48.5% vs 42.7%, P = 0.685). The incidence of grade 3/4 adverse reactions was similar between the XELOX and FOLFOX6 groups, and more patients suffered from hand-foot syndrome in the XELOX group (P = 0.018). CONCLUSION Adjuvant XELOX therapy is associated with better survival in patients after D2 dissection, but does not result in a greater survival benefit compared with FOLFOX6 therapy.

Enhancement of Nab-Paclitaxel Antitumor Activity through Addition of Multitargeting Antiangiogenic Agents in Experimental Pancreatic Cancer

Nanoparticle albumin–bound paclitaxel (nab-paclitaxel, NPT) has recently shown efficacy in pancreatic ductal adenocarcinoma (PDAC). Targeting tumor angiogenesis is a sensible combination therapeutic strategy for cancer, including PDAC. We tested the hypothesis that NPT response in PDAC can be enhanced by the mechanistically different antiangiogenic agents bevacizumab (Bev) or sunitinib (Su), despite its inherently increased tumor penetration and drug delivery. Compared with controls (19 days), median animal survival was increased after NPT therapy (32 days, a 68% increase, P = 0.0008); other regimens with enhanced survival were NPT+Bev (38 days, a 100% increase, P = 0.0004), NPT+Su (37 days, a 95% increase, P = 0.0004), and NPT+Bev+Su (49 days, a 158% increase, P = 0.0001) but not bevacizumab, sunitinib, or Bev+Su therapy. Relative to controls (100 ± 22.8), percentage net local tumor growth was 28.2 ± 23.4 with NPT, 55.6 ± 18 (Bev), 38.8 ± 30.2 (Su), 11 ± 7.2 (Bev+Su), 32.8 ± 29.2 (NPT+Bev), 6.6 ± 10.4 (NPT+Su), and 13.8 ± 12.5 (NPT+Bev+Su). Therapeutic effects on intratumoral proliferation, apoptosis, microvessel density, and stromal density corresponded with tumor growth inhibition data. In AsPC-1 PDAC cells, NPT IC50 was reduced >6-fold by the addition of sunitinib (IC25) but not by bevacizumab. In human umbilical vein endothelial cells (HUVEC), NPT IC50 (82 nmol/L) was decreased to 41 nmol/L by bevacizumab and to 63 nmol/L by sunitinib. In fibroblast WI-38 cells, NPT IC50 (7.2 μmol/L) was decreased to 7.8 nmol/L by sunitinib, but not by bevacizumab. These findings suggest that the effects of one of the most active cytotoxic agents against PDAC, NPT, can be enhanced with antiangiogenic agents, which clinically could relate to greater responses and improved antitumor results. Mol Cancer Ther; 13(5); 1032–43. ©2014 AACR.

Laparoscopy-assisted resection of proximal gastric cancer: is less than all more or less complete, or is all more, nonetheless?

The International Gastric Cancer Association and The Japanese Gastric Cancer Association 2012 In this issue of Gastric Cancer, Ahn et al. [1] present a series of 131 patients with early-stage proximal gastric cancer who underwent laparoscopic resection, either in the form of laparoscopy-assisted total gastrectomy (LATG) or that of laparoscopy-assisted proximal gastrectomy (LAPG). The comparison of these two minimally invasive techniques with assessment of multiple early and late measures of outcomes is intriguing, and although not being based on a randomized trial deserves careful recognition and analysis. Fifty LAPG patients had lower intraoperative blood loss and operative times than 81 patients after LATG, but no obvious differences of early postoperative recovery or longer-term survival outcomes were found, with the main group differences consisting of delayed complications and functional parameters. The results generally appear to be excellent, with good postoperative outcomes indicative of proper patient selection and appropriate conduct of the operative procedures. With respect to a comparison of proximal versus total gastrectomy in a laparoscopy-assisted approach, these findings seem to resemble those results found after an open approach to total and proximal gastrectomy that showed no differences between the techniques regarding early postoperative and late oncological outcomes, but indicated possible functional differences between these groups [2]. Are the authors just wrapping the old debate on total versus proximal gastrectomy for proximal gastric cancer into a minimally invasive package here, or is their experience telling us more? We think that this series highlights several relevant aspects and poses some questions that deserve further comment.

Abstract 2071: Addition of antiangiogenic agents enhances nab-paclitaxel antitumor activity in experimental pancreatic cancer.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Pancreatic ductal adenocarcinoma (PDAC) is characterized by early tissue invasion and metastasis, complex desmoplastic stromal response, and high resistance to systemic therapies. Nanoparticle albumin-bound (nab) paclitaxel (NPT) has the potential for pharmacodynamic advantages over conventional taxanes and has shown efficacy as mono- and combination therapeutic agent in several malignancies including pancreatic, lung and ovarian cancer. We evaluated the combination treatment benefits of nab-paclitaxel with the antiangiogenic agents bevacizumab (Bev) and sunitinib (Su) in experimental pancreatic cancer. In vitro cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and animal survival studies were performed in murine xenografts. Intratumoral proliferation and apoptosis were evaluated via Ki67 and TUNEL staining. Nab-paclitaxel displayed higher in vitro antiproliferative activity as a single agent in pancreatic cancer compared with gemcitabine or the polysorbate-based taxane docetaxel. In AsPC-1 PDAC cells, nab-paclitaxel IC50 was reduced more than 6-fold by an IC25 dose of sunitinib (500 nM) but not by bevacizumab (10 μg/ml). In endothelial cells HUVEC, nab-paclitaxel IC50 (82 nM) was decreased to 41 nM by bevacizumab (10 μg/ml) and to 63 nM by sunitinib (100 nM). In fibroblast WI-38 cells, nab-paclitaxel IC50 (7.2 μM) was decreased to 7.8 nM by the IC25 dose of sunitinib (2.5 μM), but no significant decrease was observed by bevacizumab (50 μg/ml) addition. Nab-paclitaxel increased stathmin phosphorylation and decreased tubulin expression in vitro. In a subcutaneous murine xenograft model, net tumor growth inhibition in NPT, Bev, Su, Bev+Su, NPT+Bev, NPT+Su and NPT+Bev+Su was 72, 44, 61, 89, 67, 93 and 86 percent. Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. In tumor tissue lysates, nab-paclitaxel caused an increase in stathmin phosphorylation but no change in tubulin expression. In an intraperitoneal murine xenograft model, compared to controls (median survival: 19 days), animal survival increased after nab-paclitaxel (32 days, p=0.0008) but not after antiangiogenic therapy with Bev (21 days), Su (24 days) or Bev+Su (22 days; for all: p=NS). Animal survival was further increased by the combination treatment of nab-paclitaxel with bevacizumab and sunitinib, with a median survival of 38, 37 and 49 days in NPT+Bev (p=0.03 vs. NPT), NPT+Su (p=0.174 vs. NPT) and NPT+Bev+Su (p=0.001 vs. NPT) groups, respectively. Nab-paclitaxel has strong antitumor activity as a single agent in this model of experimental pancreatic cancer. Nab-paclitaxel effects were further enhanced by addition of the antiangiogenic agents bevacizumab and sunitinib. These findings strongly support the potential of nab-paclitaxel based combination strategies for clinical PDAC therapy. Citation Format: Niranjan Awasthi, Changhua Zhang, Stefan Hinz, Margaret A. Schwarz, Roderich E. Schwarz. Addition of antiangiogenic agents enhances nab-paclitaxel antitumor activity in experimental pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2071. doi:10.1158/1538-7445.AM2013-2071

Abstract 2740: Antitumor activity of BMS-754807, a small molecule inhibitor of insulin-like growth factor-1 receptor / insulin receptor, in combination with gemcitabine in pancreatic cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive human malignancies characterized by late clinical presentation, rapid local and metastatic progression and high resistance to conventional therapies. Gemcitabine, an approved treatment for PDAC, has limited clinical benefits. The insulin-like growth factor (IGF) type 1 receptor (IGF-1R) has shown to be expressed in many human cancers including PDAC. The present study evaluated the therapeutic potential of BMS-754807, a small molecule inhibitor of IGF-1R and insulin receptor (IR), alone and in combination with gemcitabine, in experimental PDAC. The human PDAC cell lines were grown in RPMI 1640 medium supplemented with 10% FBS. In vitro cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and animal survival studies were performed in murine xenografts. Ki67 and TUNEL staining were used to detect intratumoral proliferation and apoptosis. PDAC cell lines AsPC-1, BxPC-3, Mia PaCa-2 and Panc-1 expressed IGF-1R and phospho-IGF-1R proteins. BMS-754807 and gemcitabine inhibited in vitro cell proliferation of PDAC cell lines; the combination of BMS-754807 with gemcitabine had additive effects. IC25 concentrations of BMS-754807 decreased gemcitabine IC50 from 9.7 μM to 75 nM for AsPC-1, from 3 μM to 70 nM for Panc-1, from 72 nM to 16 nM for Mia PaCa-2 and from 28 nM to 16 nM for BxPC-3 cells, respectively. BMS-754807 caused a significant decrease in phospho-IGF-1R and phospho-AKT proteins in AsPC-1 and Panc-1 cells. BMS-754807 and gemcitabine caused an increase in apoptosis-related PARP-1 and caspase-3 cleavage with additive effects in combination. Compared with controls, in vivo net tumor growth inhibition in BMS-754807, gemcitabine and BMS-754807+gemcitabine groups was 59 percent (p=0.05), 35 percent (p=0.02) and 94 percent (p=0.0007), respectively. Effects on intratumoral proliferation and apoptosis after BMS-754807 and gemcitabine treatments corresponded directly with tumor growth inhibition data. BMS-754807 also caused a decrease in phospho-IGF-1R and phospho-AKT in tumor tissue lysates. Median animal survival (Controls: 21 days) after BMS-754807 was 27 days (p=0.03 versus control), after gemcitabine group 28 days (p=0.05 versus control) and in the BMS-754807+gemcitabine combination group 41 days (p=0.007 versus control and p=0.02 versus gemcitabine or BMS-754807 monotherapy). BMS-754807 has strong antitumor activity in experimental PDAC, and it significantly improves gemcitabine response. These results support the potential of BMS-754807-induced mechanisms for clinical PDAC therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2740. doi:1538-7445.AM2012-2740