Superior antitumor activity of nanoparticle albumin-bound paclitaxel in experimental gastric cancer

Enhancing gastric cancer conventional chemotherapy effects by triple angiokinase inhibitor nintedanib in preclinical models

Background

Gastric adenocarcinoma (GAC) is the fourth leading cause of cancer death worldwide. Systemic chemotherapy is a preferred treatment option for advanced and recurrent GAC, but response rates and survival prolongation remain limited. Tumor angiogenesis plays a critical role in GAC growth, invasion and metastasis. We investigated the antitumor efficacy of nintedanib, a potent triple angiokinase inhibitor for VEGFR-1/2/3, PDGFR-α/β and FGFR-1/2/3, alone or in combination with chemotherapy, in preclinical models of GAC.

Methods

Animal survival studies were performed in peritoneal dissemination xenografts in NOD/SCID mice using human GAC cell lines MKN-45 and KATO-III. Tumor growth inhibition studies were performed in subcutaneous xenografts in NOD/SCID mice using human GAC cell lines MKN-45 and SNU-5. The mechanistic evaluation involved Immunohistochemistry analyses in tumor tissues obtained from subcutaneous xenografts. In vitro cell viability assays were performed using a colorimetric WST-1 reagent.

Results

In MKN-45 GAC cell-derived peritoneal dissemination xenografts, animal survival was improved by nintedanib (33%), docetaxel (100%) and irinotecan (181%), while oxaliplatin, 5-FU and epirubicin had no effect. The addition of nintedanib to docetaxel (157%) or irinotecan (214%) led to a further extension in animal survival. In KATO-III GAC cell-derived xenografts carrying FGFR2 gene amplification, nintedanib extended survival by 209%. Again, the addition of nintedanib further enhanced the animal survival benefits of docetaxel (273%) and irinotecan (332%). In MKN-45 subcutaneous xenografts, nintedanib, epirubicin, docetaxel and irinotecan reduced tumor growth (range: 68-87%), while 5-FU and oxaliplatin had a smaller effect (40%). Nintedanib addition to all chemotherapeutics demonstrated a further reduction in tumor growth. Subcutaneous tumor analysis revealed that nintedanib attenuated tumor cell proliferation, reduced tumor vasculature and increased tumor cell death.

Conclusion

Nintedanib showed notable antitumor efficacy and significantly improved taxane or irinotecan chemotherapy responses. These findings indicate that nintedanib, alone and in combination with a taxane or irinotecan, has the potential for improving clinical GAC therapy.

Study on the thermal stability of nab-paclitaxel during hyperthermic intraperitoneal chemotherapy

BACKGROUND

Albumin-bound paclitaxel (nab-paclitaxel), as a special targeted preparation of paclitaxel, has the advantages of good curative effect and less side effects in anti-tumor therapy. The existence of the plasma-peritoneal barrier and insufficient blood supply make intravenous drugs hard to reach the peritoneum, while hyperthermic intraperitoneal chemotherapy can solve the difficulty. And compared with systemic medications, HIPEC can also give higher concentrations of chemotherapy drugs in the abdominal cavity, while ensuring lower systemic toxicity. However, at present, there is no relevant report on the clinical study of nab-paclitaxel during intraperitoneal hyperthermic chemotherapy, and its stability under special temperature conditions has not been reported either.

METHODS

In this study, We examined three batches of albumin-bound paclitaxel dissolved in saline at different temperatures (25 °C, 37 °C, 41 °C, 42 °C and 43 °C) for the changes of human serum albumin content, human serum albumin polymer content, related substance content, in-vitro release rate, paclitaxel binding rate and paclitaxel content at different temperatures.

RESULTS

Our results demonstrated that the indicators including human serum albumin content, human serum albumin polymer content, in-vitro release rate, paclitaxel binding rate and paclitaxel content were stable to the several temperatures, except that Taxane (0.1%) and other individual impurities in the determination of related substance content fluctuated comparatively widely with the change of temperature. In addition, only Taxane (0.1%) and 7-Epitaxol (1%) were detected.

CONCLUSIONS

Overall, albumin-bound paclitaxel is relatively stable to different temperatures (25 °C, 37 °C, 41 °C, 42 °C and 43 °C). This study will lay a foundation for further studies on the albumin-bound paclitaxel during hyperthermic intraperitoneal chemotherapy.

pH-sensitive nanomedicine of novel tubulin polymerization inhibitor for lung metastatic melanoma

Microtubule binding agents such as paclitaxel and vincristine have activity in metastatic melanoma. However, even responsive tumors develop resistance, highlighting the need to investigate new drug molecules. Here, we showed that a new compound, CH-2-102, developed by our group, has high anti-tumor efficacy in human and murine melanoma cells. We confirmed that CH-2-102 robustly suppresses the microtubule polymerization process by directly interacting with the colchicine binding site. Our results unveil that CH-2-102 suppresses microtubule polymerization and subsequently induces G2 phase cell arrest as one of the possible mechanisms. Notably, CH-2-102 maintains its efficacy even in the paclitaxel resistance melanoma cells due to different binding sites and a non-Pgp substrate. We developed a pH-responsive drug-polymer Schiff bases linker for high drug loading into nanoparticles (NPs). Our CH-2-102 conjugated NPs induced tumor regression more effectively than Abraxane® (Nab-paclitaxel, N-PTX), free drug, and non-sensitive NPs in B16-F10 cell-derived lung metastasis mouse model. Furthermore, our results suggest that the formulation has a high impact on the in vivo efficacy of the drug and warrants further investigation in other cancers, particularly taxane resistant. In conclusion, the microtubule polymerization inhibitor CH-2-102 conjugated pH-responsive NPs induce tumor regression in lung metastasis melanoma mice, suggesting it may be an effective strategy for treating metastatic melanoma.

Targeted FGFR/VEGFR/PDGFR inhibition with dovitinib enhances the effects of nab-paclitaxel in preclinical gastric cancer models

Standard chemotherapy regimens for gastric adenocarcinoma (GAC) have limited efficacy and considerable toxicity profiles. Nab-paclitaxel has shown promising antitumor benefits in previous GAC preclinical studies. Dovitinib inhibits members of the receptor tyrosine kinase family including FGFR, VEGFR and PDGFR, and has exhibited antitumor effects in many solid tumors including GAC. Based on the antimitotic, antistromal and EPR effects of nab-paclitaxel, we investigated augmentation of nab-paclitaxel response by dovitinib in multiple GAC preclinical models. In MKN-45 subcutaneous xenografts, inhibition in tumor growth by nab-paclitaxel and dovitinib was 75% and 76%, respectively. Dovitinib plus nab-paclitaxel had an additive effect on tumor growth inhibition and resulted in tumor regression (85% of its original value). Dovitinib monotherapy resulted in minimal improvement in animal survival (25 days) compared to control (23 days), while nab-paclitaxel monotherapy or dovitinib plus nab-paclitaxel combination therapy led to a clinically significant lifespan extension of 83% (42 days) and 187% (66 days), respectively. IHC analysis of subcutaneous tumors exhibited reduced tumor cell proliferation and tumor vasculature by dovitinib. In vitro studies demonstrated that dovitinib and nab-paclitaxel individually reduced tumor cell proliferation, with an additive effect from combination therapy. Immunoblot analyses of MKN-45 and KATO-III cells revealed that dovitinib decreased phospho-FGFR, phospho-AKT, phospho-ERK, phospho-p70S6K, phospho-4EBP1, Bcl-2 and increased cleaved PARP-1, cleaved-caspase-3, p27, Bax, Bim, with an additive effect from combination therapy. These results demonstrate that the FGFR/VEGFR/PDGFR inhibitor, dovitinib, has the potential to augment the antitumor effects of nab-paclitaxel, with implications for use in the advancement of clinical GAC therapy.

Apatinib inhibits the proliferation of gastric cancer cells via the AKT/GSK signaling pathway in vivo

Gastric cancer (GC) is the third leading cause of cancer-associated mortality globally. Although the diagnosis and therapeutic strategies for GC have improved, the prognosis for advanced gastric cancer (AGC) remains poor. Hence, the present study sought to design a zebrafish model established by microinjecting human MGC-803 GC cell line for studying personalized molecular-targeted cancer therapy. Apatinib, a novel molecular-targeted agent, was evaluated for its in vivo efficacy through a comparison among the control groups (no treatment) and subject groups (treatment). Newly formed vessel length and tumor volume were measured in all of the groups for further study. The length of newly formed vessels was obviously shortened after apatinib treatment in the zebrafish model established in this study. Meanwhile, apatinib exhibited the best antitumor growth effect with dose and time dependence by suppressing AKT/GSK3α/β signaling, which may be the mechanism underlying the profound antitumor clinical effect of apatinib. The data indicated that apatinib therapy exerts an anti-angiogenesis effect and it can be recommended as a proper antitumor growth therapy for GC patients. Additionally, zebrafish models could be designed as a potential practical tool to explore new anti-GC cancer drugs.

Targeted dual inhibition of c-Met/VEGFR2 signalling by foretinib improves antitumour effects of nanoparticle paclitaxel in gastric cancer models

Elevated expression of multiple growth factors and receptors including c‐Met and VEGFR has been reported in gastric adenocarcinoma (GAC) and thus provides a potentially useful therapeutic target. The therapeutic efficacy of foretinib, a c‐Met/VEGFR2 inhibitor, was determined in combination with nanoparticle paclitaxel (NPT) in GAC. Animal studies were conducted in NOD/SCID mice in subcutaneous and peritoneal dissemination xenografts. The mechanism of action was assessed by Immunohistochemical and Immunoblot analyses. In c‐Met overexpressing MKN‐45 cell‐derived xenografts, NPT and foretinib demonstrated inhibition in tumour growth, while NPT plus foretinib showed additive effects. In c‐Met low‐expressing SNU‐1 or patient‐derived xenografts, the foretinib effect was smaller, while NPT had a similar effect compared with MKN‐45, as NPT plus foretinib still exhibited an additive response. Median mice survival was markedly improved by NPT (83%), foretinib (100%) and NPT plus foretinib (230%) in peritoneal dissemination xenografts. Subcutaneous tumour analyses exhibited that foretinib increased cancer cell death and decreased cancer cell proliferation and tumour vasculature. NPT and foretinib suppressed the proliferation of GAC cells in vitro and had additive effects in combination. Further, foretinib caused a dramatic decrease in phosphorylated forms of c‐Met, ERK, AKT and p38. Foretinib led to a decrease in Bcl‐2, and an increase in p27, Bax, Bim, cleaved PARP‐1 and cleaved caspase‐3. Thus, these findings highlight the antitumour impact of simultaneous suppression of c‐Met and VEGFR2 signalling in GAC and its potential to enhance nanoparticle paclitaxel response. This therapeutic approach might lead to a clinically beneficial combination to increase GAC patients’ survival.

The Anti-Tumor Effect of Nab-Paclitaxel Proven by Patient-Derived Organoids

Background

Nab-paclitaxel has been widely used in treating breast cancer and pancreatic patients for its low toxicity and high efficiency. However, its role in gastric cancer (GC) remains ambiguous. The aim of our study was to test the anti-tumor activity of nab-paclitaxel using GC patient-derived organoids.

Methods

By using the organoid culture system, we describe the establishment of human gastric cancer organoid lines from surgical samples of three patients with gastric cancer. The consistency of these organoids with original cancer tissues was evaluated by histopathological examination. The characteristics of the cancer organoids were tested using immunofluorescence (IF) staining. Using organoids, the anti-tumor efficiencies of nab-paclitaxel, 5-Fu and epirubicin were compared by CCK8 assay and Annexin V-FITC/PI staining.

Results

Three organoids were successfully established and passaged. The morphology of the established GC organoids was consistent with original cancer tissues. The IC50 of nab-paclitaxel was 3.68 μmol/L in hGCO1, 2.41 μmol/L in hGCO2 and 2.91 μmol/L in hGCO3, which was significantly lower than those of 5-FU (72.99 μmol/L in hGCO1, 28.32 μmol/L in hGCO2 and 2.91 μmol/L in hGCO3) and epirubicin (25.85μmol/L in hGCO1, 15.15 μmol/L in hGCO2 and 7.60 μmol/L in hGCO3). When each organoid lines were treated with nab-paclitaxel for increasing period of time, the percentage of the apoptotic cells in each organoid increased accordingly.

Conclusion

Nab-paclitaxel showed strong anti-tumor activity and had the potential to become front-line drug for treating GC patients. Gastric cancer organoid may be a good tool to predict in vivo response to drugs.

A Gastric Cancer Peptide GX1-Modified Nano-Lipid Carriers Encapsulating Paclitaxel: Design and Evaluation of Anti-Tumor Activity

Aim

The aim of this study was to develop a GX1-modified nanostructured lipid carrier (NLCs) and to evaluate its ability to improve the anti-gastric cancer tumor effects of paclitaxel (PTX).

Main Methods

The GX1-modified NLCs were synthesized and loaded with PTX (GX1-PTX-NLCs) by emulsion solvent evaporation technique. The anti-tumor activity and pharmacodynamics were then evaluated by in vitro cell studies and animal experiments.

Key Findings

The GX1-modified NLCs were successfully synthesized and confirmed by ¹H NMR and MALDI-TOF-MS. PTX-loaded NLCs produced particles with average size distribution less than or equal to 222 nm and good drug loading and entrapment efficiency. In vitro studies demonstrated that GX1-PTX-NLCs had a more obvious inhibitory effect on Co-HUVEC cells than PTX and unmodified PTX-NLCs. The cellular uptake results also showed that GX1-PTX-NLCs were largely concentrated in Co-HUVEC cells, and the uptake rates of GX1-PTX-NLCs in Co-HUVEC were higher than those of the free drug and the PTX-NLC. In vivo studies demonstrated that GX1-PTX-NLCs possess strong anti-tumor effect and showed higher tumor growth inhibition and lower toxicity in nude mice.

Significance

These results suggest that GX1-modified NLCs enhanced the anti-tumor activity of PTX and reduced its toxicity effectively. GX1-PTX-NLCs may be considered as a potent drug delivery system for therapy of gastric cancer.

Nanoparticle albumin-bound paclitaxel: a big nano for the treatment of gastric cancer

Gastric cancer (GC) is the third cause of cancer-related death worldwide. Patients with unresectable GC can be treated with chemotherapy such as paclitaxel, which is a microtubule stabilizer. The use of nanoparticle albumin-bound paclitaxel (nab-ptx) avoids hypersensitivity reactions due to the absence of solvent needed to dissolve paclitaxel and it can be administered at higher doses. The ABSOLUTE randomized phase-3 clinical trial showed the non-inferiority of the nab-ptx used every week compared to the solvent-based paclitaxel used every week. This review describes the current advancements of the use of nab-ptx in GC in preclinical and clinical study investigations. The possibility of combining nab-ptx with other medications to improve response of patients to their specific molecular needs will also be debated.

S-1 combined with paclitaxel may benefit advanced gastric cancer: Evidence from a systematic review and meta-analysis

BACKGROUND

Gastric cancer, as one of the increasingly common malignancies, has experienced high morbidity throughout many countries at present. Currently, chemotherapy regimen with more efficacy and safety for advanced gastric cancer (AGC) is needed. We aimed to assess the clinical efficacy and safety of S-1 combined with paclitaxel (PTX) for AGC by performing a systematic review and meta-analysis of the published studies.

METHOD

All published randomized controlled trials (RCTs) of S-1 combined with PTX for AGC were searched. Studies that included patients with locally advanced or metastases' gastric cancers were included. We searched the databases included Cochrane Library of Clinical Comparative Trials, MEDLINE, Embase, American Society of Clinical Oncology meeting abstracts and China National Knowledge Internet (CNKI) from 2000 to 2018. We searched the database up to January 2018. The first endpoint was overall survival (OS). Other endpoints were progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR). Safety analyses were also performed.

RESULTS

A total of 7 trials (including 1407 patients, 711 patients in intervention group and 696 patients in control group) were included in the present analysis. S-1 combined with PTX significantly improved the OS [HR = 0.78, 95% CI: 0.60-0.97, P = 0.000],PFS [HR = 0.70, 95% CI: 0.55-0.85, P = 0.000], ORR [RR = 1.30, 95%CI: 1.05-1.60, P = 0.017] and DCR [RR = 1.15, 95%CI: 1.04-1.27, P = 0.008] of patients with AGC. The grade 3 or 4 haematological and non-hematologic toxicities were anemia [RR = 1.71, 95% CI: 1.04-2.79, P = 0.03], neutropenia [RR = 1.65, 95% CI: 1.32-2.06, P < 0.0001] and anorexia [RR = 1.66, 95% CI: 1.05-2.64, P = 0.03] respectively.

CONCLUSION

S-1 combined with PTX may be a good choice for patients with AGC. S-1 plus PTX experienced more efficacy and safety when compared with S-1 alone or S-1 plus other drugs.

Augmentation of Nab-Paclitaxel Chemotherapy Response by Mechanistically Diverse Antiangiogenic Agents in Preclinical Gastric Cancer Models

Gastric adenocarcinoma (GAC) remains the third most common cause of cancer-related deaths worldwide. Systemic chemotherapy is commonly recommended as a fundamental treatment for metastatic GAC; however, standard treatment has not been established yet. Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated therapeutic benefits of mechanistically diverse antiangiogenic agents in combination with nab-paclitaxel, a next-generation taxane, in preclinical models of GAC. Murine survival studies were performed in peritoneal dissemination models, whereas tumor growth studies were performed in subcutaneous GAC cell-derived or patient-derived xenografts. The mechanistic evaluation involved IHC and Immunoblot analysis in tumor samples. Nab-paclitaxel increased animal survival that was further improved by the addition of antiangiogenic agents ramucirumab (or its murine version DC101), cabozantinib and nintedanib. Nab-paclitaxel combination with nintedanib was most effective in improving animal survival, always greater than 300% over control. In cell-derived subcutaneous xenografts, nab-paclitaxel reduced tumor growth while all three antiangiogenic agents enhanced this effect, with nintedanib demonstrating the greatest inhibition. Furthermore, in GAC patient-derived xenografts the combination of nab-paclitaxel and nintedanib reduced tumor growth over single agents alone. Tumor tissue analysis revealed that ramucirumab and cabozantinib only reduced tumor vasculature, whereas nintedanib in addition significantly reduced tumor cell proliferation and increased apoptosis. Effects of nab-paclitaxel, a promising chemotherapeutic agent for GAC, can be enhanced by new-generation antiangiogenic agents, especially nintedanib. The data suggest that nab-paclitaxel combinations with multitargeted antiangiogenic agents carry promising potential for improving clinical GAC therapy. Mol Cancer Ther; 17(11); 2353-64. ©2018 AACR.

Heregulin-expressing HER2-positive breast and gastric cancer exhibited heterogeneous susceptibility to the anti-HER2 agents lapatinib, trastuzumab and T-DM1

Background

Overexpression of heregulin, a HER3 ligand, is one mechanism that confers resistance to the anti-HER2 agents trastuzumab and lapatinib. We investigated the impact of heregulin expression on the efficacy of HER2-targeted therapeutic agents, including trastuzumab, trastuzumab emtansine (T-DM1) and lapatinib, in vitro and in vivo and evaluated the heregulin messenger RNA (mRNA) levels in specimens from patients with HER2-positive breast or gastric cancer.

Results

Cell proliferation and apoptosis assays demonstrated that heregulin conferred robust resistance to lapatinib and trastuzumab via HER3-Akt pathway activation followed by survivin overexpression; however, heregulin conferred minimal or no resistance to T-DM1 and paclitaxel. The heregulin mRNA level of one of 10 patients was up-regulated after the acquisition of resistance to trastuzumab-based therapy.

Materials and Methods

SK-BR-3, NCI-N87, BT-474, MDA-MB-453, HCC1954, SNU-216 and 4-1ST cells were pharmacologically treated with recombinant heregulin or transfected with the heregulin gene. We also assessed the expression of heregulin mRNA in HER2-positive breast or gastric cancer samples before and after trastuzumab-based therapy using a RT-PCR-based method.

Conclusions

mRNA up-regulation of heregulin was observed in clinical breast cancer specimens during trastuzumab-based treatment, but heregulin overexpression had a limited effect on the sensitivity to T-DM1 in vitro and in vivo.

Superior Therapeutic Efficacy of Nanoparticle Albumin Bound Paclitaxel Over Cremophor-Bound Paclitaxel in Experimental Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is the fastest growing cancer in the western world and the overall 5 year survival rate of EAC is below 20%. Most patients with EAC present with locally advanced or widespread metastatic disease, where current treatment is largely ineffective. Therefore, new therapeutic approaches are urgently needed. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is a novel albumin-stabilized, cremophor-free and water soluble nanoparticle formulation of paclitaxel, and the potential role of nab-paclitaxel has not been tested yet in experimental EAC. Here we tested the antiproliferative and antitumor efficacy with survival advantage of nab-paclitaxel as monotherapy and in combinations in in-vitro, and in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC. Nab-paclitaxel significantly inhibited in-vitro cell proliferation with higher in-vivo antitumour efficacy and survival benefit compared to paclitaxel or carboplatin treatments both in mono- and combination therapies. Nab-paclitaxel treatment increased expression of mitotic-spindle associated phospho-stathmin, decreased expression of proliferative markers and enhanced apoptosis. This study demonstrates that nab-paclitaxel had stronger antiproliferative and antitumor activity in experimental EAC than the current standard chemotherapeutic agents which supports the rationale for its clinical use in EAC.

Inhibition of nuclear factor κB transcription activity drives a synergistic effect of cisplatin and oridonin on HepG2 human hepatocellular carcinoma cells

Activation of nuclear factor κB (NF-κB) by cisplatin and other chemotherapeutics is responsible, at least in part, for the development of drug resistance in the treatment of hepatocellular carcinoma. Therefore, a combination of chemotherapeutics with NF-κB inhibitors could overcome resistance of cancer cells. Oridonin is a diterpenoid isolated from Rabdosia rubescens that can block the NF-κB signaling cascades. In this study, we investigated the synergistic effect of oridonin and cisplatin on human hepatocellular carcinoma HepG2 cells. Cell apoptosis and mitochondrial membrane potential loss were examined using Hoechst 33258 and rhodamine-123 staining, followed by flow cytometry, respectively. The expression of apoptosis-related proteins and NF-κB subunits was detected by real-time PCR and western blot. The activity of caspase 3 and 9 was measured using the Caspase Activity Kit. Electrophoretic mobility shift assay and the enzyme-linked immunosorbent assay-based kit were used to assess the DNA-binding activity of NF-κB. We found a synergistic antitumor effect between cisplatin and oridonin on HepG2 cells both in vitro and in vivo. In addition, the combination of cisplatin and oridonin synergistically induces apoptosis and regulates the expression and activity of several key apoptosis-related proteins. Furthermore, the combination treatment not only downregulates nuclear translocation of p50 and p65, but more significantly, decreases the transcription activity of all NF-κB subunits to a greater degree than either agent alone. Our results suggest that the synergistic effect between both agents is likely to be driven by the inhibition of transcription activity of NF-κB and the resulting increased apoptosis.

The antitumor effects of oncolytic adenovirus H101 against lung cancer

Lung cancer is the leading cause of cancer mortality in both men and women, with dismal survival rates due to late-stage diagnoses and a lack of efficacious therapies. The new treatment options with completely novel mechanism of therapeutic activity are needed for lung cancer to improve patient outcome. The present study was aimed at testing the efficacy of recombinant adenovirus H101 as an oncolytic agent for killing human lung cancer cell lines in vitro and in vivo. We assessed the coxsackievirus adenovirus receptor (CAR) expression on human lung cancer cell lines by RT-PCR and immunocytochemistry staining. Viral infectivity and viral replication in lung cancer cells was assayed by flow cytometry and real-time fluorescent quantitative PCR. After H101 treatment, cytotoxic effect, cell cycle progression and apoptosis were further examined by lactate dehydrogenase release assay and flow cytometry in vitro, respectively. In vivo, antitumor effects of H101 were assessed on SCID Beige mice xenografted with human lung cancer cells. Receptor characterization confirmed that human lung cancer cell lines expressed CAR receptor for adenovirus type 5. Lung cancer cells were sensitive to infection by the H101 virus. H101 infection and replication resulted in very potent cytotoxicity, G2/M phase arrest and cell lysis. In vivo, we also showed that H101 significantly inhibited tumor growth following intratumoral injection, with virus replication, cell degeneration and necrosis in the tumor tissue. These results have important implications for the treatment of human lung cancer.

Nanotechnology for cancer treatment

Nanotechnology has the potential to increase the selectivity and potency of chemical, physical, and biological approaches for eliciting cancer cell death while minimizing collateral toxicity to nonmalignant cells. Materials on the nanoscale are increasingly being targeted to cancer cells with great specificity through both active and passive targeting. In this review, we summarize recent literature that has broken new ground in the use of nanotechnology for cancer treatment with an emphasis on targeted drug delivery.

A click approach to novel D-ring-substituted 16α-triazolylestrone derivatives and characterization of their antiproliferative properties

A simple and efficient synthesis of novel, D-ring substituted estrone derivatives containing a 16α-triazolyl moiety is described. Two epimeric azido alcohols (16α-azido-17α-hydroxy and 16α-azido-17β-hydroxy) of estra-1,3,5(10)-triene-3-methyl ether were prepared, followed by copper(I)-catalyzed azide-alkyne cycloaddition with various terminal alkynes. The steroidal triazoles were obtained in high yields and their activities against three human cancer cell lines (HeLa, MCF7 and A431) were screened. The most effective analogs were submitted to additional experiments in order to characterize their antiproliferative properties. As evidenced by flow cytometry, the selected steroids induced a disturbance in the HeLa cell cycle in a concentration- and exposure-dependent manner, through an increase of the hypodiploid population (subG1) and a cell cycle arrest in the G2/M phase. A noncancerous human fibroblast cell line (MRC5) was used to determine the selectivities of these compounds. Fluorescent microscopy after Hoechst 33258 - propidium iodide (HOPI) double staining revealed nuclear condensation and disturbed cell membrane integrity. The enhanced activities of caspase-3 and caspase-9 without activation of caspase-8 in the treated cells indicated the activation of the intrinsic pathway of apoptosis. The levels of cell cycle regulators (CDK1, cyclin B1/B2 and cdc25B) were decreased and the ratio Bax/Bcl-2 was increased 24 h after the treatment of HeLa cells (determined at an mRNA level by means of an RT-PCR technique). Under the same conditions, two agents elicited substantially increased degrees of phosphorylation of stathmin, as evidenced by Western blotting. The presented results demonstrate that these steroids can be regarded as appropriate structural scaffolds for the design and synthesis of further steroid analogs as innovative drug candidates with good efficacy.

Silencing stathmin-modulating efficiency of chemotherapy for esophageal squamous cell cancer with paclitaxel

Paclitaxel (PTX) is broadly considered the drug of choice for treating human esophageal squamous cell cancer (ESCC). However, PTX resistance often ultimately leads to treatment failure. stathmin, or Op18, is a ubiquitously expressed 19-kDa cytosolic phosphoprotein that can integrate various cellular regulatory signals. stathmin overexpression could lead to resistance to chemotherapeutic agents. In this study we investigated the effect of stathmin gene silencing, using small interfering RNA (stathmin siRNA), on the efficacy of PTX in ESCC. Transfection of stathmin siRNA could significantly inhibit stathmin mRNA and protein levels in ESCC cell lines EC9706 and Eca-109. The silencing of stathmin combined with PTX significantly inhibited the proliferation of EC9706 and Eca-109 cells, with a significantly higher proportion of cells at G2/M phase and this antiproliferative effect was accompanied by an increase in apoptosis rates and morphology changes of EC9706 and Eca-109. Thus, combined chemotherapeutic agent PTX and stathmin siRNA could potentially enhance the therapeutic outcomes of PTX in treating ESCC.

Nuclear survivin expression: a prognostic factor for the response to taxane-platinum chemotherapy in patients with advanced non-small cell lung cancer

Survivin, a structurally unique protein expressed in most common human neoplasms, is thought to support cell cycle progression and suppress apoptosis. Survivin expression is highly correlated with advanced non-small cell lung cancer (NSCLC) and poor prognosis. In this retrospective study of banked pathology tissue of patients with advanced NSCLC, we tested for correlations of N-survivin expression in tumor tissues and responsiveness to treatment with platinum-based regimens containing paclitaxel or docetaxel. The 48 patients with NSCLC included 32 (66.7 %) males and 16 (33.3 %) females. Mean age at diagnosis was 59.4 years (range 36-83 years), and median follow-up time was 20.4 months (range 3.4-59.0 months). Patients with high tumor N-survivin expression had significantly better responses to taxane-platinum chemotherapy than those with low tumor N-survivin expression (P < 0.001). Adjusted multivariate modeling found high tumor N-survivin expression to be an independent prognostic factor for a clinical response to chemotherapy (high vs. low, OR 6.14, 95 % CI 1.62-23.29; P = 0.008). Median overall survival differed significantly between those with high tumor N-survivin expression who did/did not respond to chemotherapy and between those with low tumor N-survivin expression who did/did not respond to chemotherapy (P < 0.05). Tumor N-survivin expression shows promise as a predictive biomarker in the chemotherapy setting as a surrogate marker of high proliferation status.

The dual PI3K/mTOR inhibitor NVP-BEZ235 enhances nab-paclitaxel antitumor response in experimental gastric cancer

Gastric cancer is the second most common cause of cancer-related deaths worldwide. Taxanes have shown therapeutic effects against gastric cancer while also activating the PI3K/mTOR signaling pathway. We investigated the effects of NVP-BEZ235 (BEZ235), a novel dual PI3K/mTOR inhibitor, alone and in combination with nanoparticle albumin-bound (nab)-paclitaxel in experimental gastric cancer. Cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and survival studies were performed in murine xenografts. Phosphorylated mTOR and 4E-BP1 levels were elevated in gastric cancer cells and tumor tissues by nab-paclitaxel. BEZ235 effectively inhibited cell proliferation in vitro and provided additive effects in combination with nab-paclitaxel. Furthermore, BEZ235 blocked the activated PI3K/mTOR pathway either alone or in combination with nab-paclitaxel in gastric cancer cells. BEZ235 and nab-paclitaxel caused an increase in PARP-1 and caspase-3 cleavage. Net local tumor growth inhibition for the BEZ235, nab-paclitaxel and BEZ235+nab-paclitaxel groups was 45.1, 77.9 and 97% compared to controls. The effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. BEZ235 also caused a decrease in phospho-mTOR and phospho-Akt in tumor tissue lysates. Median animal survival (controls, 23 days) was 26.5 days after BEZ235 (p=0.227), 90.5 days after nab-paclitaxel (p=0.001) and 97 days in the BEZ235+nab-paclitaxel combination treatment group (p=0.001). Our findings suggest that BEZ235 exerts some antitumor effects against gastric cancer and enhances effects of nab-paclitaxel through inhibition of cell proliferation and modulation of the PI3K/mTOR pathway. This approach may represent a promising combination targeted therapy for gastric cancer.