Gallbladder cancer treatment using adenovirus expressing the HGF/NK4 gene in a peritoneal implantation model

Overview of current targeted therapy in gallbladder cancer

Gallbladder cancer (GBC) is rare, but is the most malignant type of biliary tract tumor. Unfortunately, only a small population of cancer patients is acceptable for the surgical resection, the current effective regimen; thus, the high mortality rate has been static for decades. To substantially circumvent the stagnant scenario, a number of therapeutic approaches owing to the creation of advanced technologic measures (e.g., next-generation sequencing, transcriptomics, proteomics) have been intensively innovated, which include targeted therapy, immunotherapy, and nanoparticle-based delivery systems. In the current review, we primarily focus on the targeted therapy capable of specifically inhibiting individual key molecules that govern aberrant signaling cascades in GBC. Global clinical trials of targeted therapy in GBC are updated and may offer great value for novel pathologic and therapeutic insights of this deadly disease, ultimately improving the efficacy of treatment.

Assessment of pharmacokinetic interaction between rilotumumab and epirubicin, cisplatin and capecitabine (ECX) in a Phase 3 study in gastric cancer

AIMS

Rilotumumab is a fully human monoclonal antibody investigated for the treatment of MET-positive gastric cancer. The aim of this study was to evaluate the potential pharmacokinetic (PK)-based drug-drug interaction (DDI) between rilotumumab and epirubicin (E), cisplatin(C) and capecitabine (X).

METHODS

This was a Phase 3 double-blind, placebo-controlled study, in which rilotumumab, epirubicin and cisplatin were administered intravenously at 15 mg kg^-1 , 50 mg m^-2 , and 60 mg m^-2 Q3W, respectively, while capecitabine was given orally at 625 mg m^-2 twice daily. Rilotumumab PK samples were taken at pre-dose and at the end-of-infusion from all patients in cycles 1, 3, 5 and 7. ECX PK samples were taken in cycle 3 from patients who participated in the intensive PK assessment. ECX PK was assessed by non-compartmental (NCA) analyses and PK parameters were compared between two arms. Rilotumumab PK was assessed by comparing the observed rilotumumab serum concentrations with model-predicted concentrations using a population PK model developed from previous Phase 1 and Phase 2 studies.

RESULTS

The study enrolled 609 patients. ECX plasma concentrations in the presence and absence of rilotumumab were similar, as demonstrated by the geometric mean ratios for C_max and AUC, which were close to 1.0, suggesting ECX PK was not affected by co-administration of rilotumumab. The observed rilotumumab serum concentrations were similar to the values predicted by population PK modelling on the basis of a prediction-corrected visual predictive check, indicating rilotumumab exposure was not affected by co-administration of ECX.

CONCLUSIONS

The results suggest lack of PK-based DDI between rilotumumab and ECX.

Material properties of viral nanocages explored by atomic force microscopy

Single-particle nanoindentation by atomic force microscopy (AFM) is an emergent technique to characterize the material properties of nano-sized proteinaceous systems. AFM uses a very small tip attached to a cantilever to scan the surface of the substrate. As a result of the sensitive feedback loop of AFM, the force applied by the tip on the substrate during scanning can be controlled and monitored. By accurately controlling this scanning force, topographical maps of fragile substrates can be acquired to study the morphology of the substrate. In addition, mechanical properties of the substrate like stiffness and breaking point can be determined by using the force spectroscopy capability of AFM. Here we discuss basics of AFM operation and how this technique is used to determine the structure and mechanical properties of protein nanocages, in particular viral particles. Knowledge of morphology as well as mechanical properties is essential for understanding viral life cycles, including genome packaging, capsid maturation, and uncoating, but also contributes to the development of diagnostics, vaccines, imaging modalities, and targeted therapeutic devices based on viruslike particles.

Regulation of cell proliferation and migration in gallbladder cancer by zinc finger X-chromosomal protein

Gallbladder carcinoma (GBC) is one of the mostly aggressive and fatal malignancies. However, little is known about the oncogenic genes that contributed to the development of GBC. Zinc finger X-chromosomal protein (ZFX) was a novel member of the Krueppel C2H2-type zinc-finger protein family and its down-regulation led to impaired cell growth in human laryngeal squamous cell carcinoma. Here, we aim to investigate the function of ZFX in GBC cell proliferation and migration. Loss of function analysis was performed on GBC cell line (GBC-SD) using lentivirus-mediated siRNA against ZFX. The proliferation, in vitro tumorigenesis (colony-formation) ability as well as cell migration was significantly suppressed after GBC-SD cells which were infected with ZFX-siRNA-expressing lentivirus (Lv-shZFX). Our finding suggested that ZFX promoted the growth and migration of GBC cells and could present a potential molecular target for gene therapy of GBC.

Hepatocyte growth factor and Met in tumor biology and therapeutic approach with NK4

Hepatocyte growth factor (HGF) and Met/HGF receptor tyrosine kinase play a role in the progression to invasive and metastatic cancers. A variety of cancer cells secrete molecules that enhance HGF expression in stromal fibroblasts, while fibroblast-derived HGF, in turn, is a potent stimulator of the invasion of cancer cells. In addition to the ligand-dependent activation, Met receptor activation is negatively regulated by cell-cell contact and Ser985 phosphorylation in the juxtamembrane of Met. The loss of intercellular junctions may facilitate an escape from the cell-cell contact-dependent suppression of Met-signaling. Significance of juxtamembrane mutations found in human cancers is assumed to be a loss-of-function in the negative regulation of Met. In attempts to block the malignant behavior of cancers, NK4 was isolated as a competitive antagonist against HGF-Met signaling. Independently on its HGF-antagonist action, NK4 inhibited angiogenesis induced by vascular endothelial cell growth factor and basic fibroblast growth factor, as well as HGF. In experimental models of distinct types of cancers, NK4 inhibited Met activation and this was associated with inhibition of tumor invasion and metastasis. NK4 inhibited tumor angiogenesis, thereby suppressing angiogenesis-dependent tumor growth. Cancer treatment with NK4 suppresses malignant tumors to be "static" in both tumor growth and spreading.

Suppression of human colon tumor growth by adenoviral vector-mediated NK4 expression in an athymic mouse model

AIM: To investigate the suppressive effects of adenoviral vector-mediated expression of NK4, an antagonist of hepatocyte growth factor (HGF), on human colon cancer in an athymic mouse model to explore the possibility of applying NK4 to cancer gene therapy.

METHODS: A human colon tumor model was developed by subcutaneous implantation of tumor tissue formed by LS174T cells grown in athymic mice. Fifteen tumor-bearing mice were randomized into three groups (n = 5 in each group) at d 3 after tumor implantation and mice were injected intratumorally with phosphate-buffered saline (PBS) or with recombinant adenovirus expressing β-galactosidase (Ad-LacZ) or NK4 (rvAdCMV/NK4) at a 6-d interval for total 5 injections in each mouse. Tumor sizes were measured during treatment to draw a tumor growth curve. At d 26 after the first treatment, all animals were sacrificed and the tumors were removed to immunohistochemically examine proliferating cell nuclear antigen (PCNA), microvessel density (represented by CD31), and apoptotic cells. In a separate experiment, 15 additional athymic mice were employed to develop a tumor metastasis model by intraperitoneal injection (ip) of LS174T cells. These mice were randomized into 3 groups (n = 5 in each group) at d 1 after injection and were treated by ip injection of PBS, or Ad-LacZ, or rvAdCMV/NK4 at a 6-d interval for total two injections in each mouse. All animals were sacrificed at d 14 and the numbers and weights of disseminated tumors within the abdominal cavity were measured.

RESULTS: Growth of human colon tumors were significantly suppressed in the athymic mice treated with rvAdCMV/NK4 (2537.4 ± 892.3 mm³) compared to those treated by either PBS (5175.2 ± 1228.6 mm³) or Ad-LacZ (5578.8 ± 1955.7 mm³) (P < 0.05). The tumor growth inhibition rate was as high as 51%. Immunohistochemical staining revealed a similar PCNA labeling index (75.1% ± 11.2% in PBS group vs 72.8% ± 7.6% in Ad-LacZ group vs 69.3% ± 9.4% in rvAdCMV/NK4 group) in all groups, but significantly lower microvessel density (10.7 ± 2.4 in rvAdCMV/NK4 group vs 25.6 ± 3.8 in PBS group or 21.3 ± 3.5 in Ad-LacZ group, P < 0.05), and a markedly higher apoptotic index (7.3% ± 2.4% in rvAdCMV/NK4 group vs 2.6 ± 1.1% in PBS group or 2.1% ± 1.5% in Ad-LacZ group, P < 0.05) in the rvAdCMV/NK4 group compared to the two control groups. In the tumor metastasis model, the number and weight of disseminated tumors of mice treated with rvAdCMV/NK4 were much lower than those of the control groups (tumor number: 6.2 ± 3.3 in rvAdCMV/NK4 group vs 22.9 ± 7.6 in PBS group or 19.8 ± 8.5 in Ad-LacZ group, P < 0.05; tumor weight: 324 ± 176 mg in rvAdCMV/NK4 group vs 962 ± 382 mg in PBS group or 1116 ± 484 mg in Ad-LacZ group, P < 0.05).

CONCLUSION: The recombinant adenovirus, rvAdCMV/NK4, can attenuate the growth of colon cancer in vivo, probably by suppressing angiogenesis and inducing tumor cell apoptosis, but not by direct suppression of tumor cell proliferation. Moreover, rvAdCMV/NK4 may inhibit peritoneal dissemination of colon cancer cells in a murine tumor metastasis model. These findings indicate that NK4 gene transfer may be an effective tool for the treatment of colon cancer.

Growth factors in pleural fibrosis

PURPOSE OF REVIEW

Pleural fibrosis is a double-edged sword in clinical settings. Successful induction of pleural fibrosis is the basis of therapeutic pleurodesis. On the other hand, pleural septations and fibrosis are undesirable outcomes in pleural infection and fibrothoraces. The significance of growth factors in the pathogenesis of pleural fibrosis has become increasingly apparent.

RECENT FINDINGS

Recent findings have indicated that transforming growth factor beta is a key mediator of pleural fibrosis and demonstrated the therapeutic potential of both transforming growth factor beta itself and transforming growth factor beta inhibitors. Basic fibroblast growth factor has been highlighted as a key factor in successful pleurodesis, and in the formation of pleural effusions. Vascular endothelial growth factor inhibition has been shown to decrease pleural fibrosis in vivo. By contrast, hepatocyte growth factor stimulates non-fibrotic healing, while inhibition increases fibrosis.

SUMMARY

The actions of the growth factors, and their inhibitors, are potentially and/or currently applicable in a clinical setting. Understanding the biology of these growth factors may allow therapeutic manipulation of these cytokines to create pleurodesis or to inhibit pleural (and peritoneal) adhesion/fibrosis.

Inhibition of angiogenesis and HGF-cMET-elicited malignant processes in human hepatocellular carcinoma cells using adenoviral vector-mediated NK4 gene therapy

NK4 is an hepatocyte growth factor (HGF)-antagonist and a broad angiogenesis inhibitor. NK4 gene therapy has confirmed antitumor efficacy on cancers with intact HGF-cMET signaling pathway. However, the feasibility to treat tumors in which the effect of the HGF-cMET signaling pathway is less unambiguous or may even be inhibitory on carcinogenesis, such as hepatocellular carcinoma (HCC) with NK4 needs further assessment. Therefore, we evaluated the effects of adenoviral vector-mediated expression of NK4 on the biological behavior of a series of HCC cell lines in vitro and on HepG2 xenografts in vivo. In vitro, transduction of HCC cell lines with the replication-deficient recombinant adenoviral vector AdCMV.NK4 resulted in significant inhibition of proliferation over and above the antimitogenic effects of HGF. In addition, HGF-induced scattering and invasion through matrigel were inhibited effectively. Moreover, transduced HCC cells produced sufficient amounts of NK4 protein to achieve bystander effects involving reduced migration of nontransduced tumor cells and reduced proliferation of endothelial cells. Finally, treatment of established HepG2 xenografts with AdCMV.NK4 resulted in significant tumor growth delay and significant reduction of intratumoral microvessel density. In conclusion, NK4 gene therapy is a promising strategy to treat HCC based on the pleiotropic functions of NK4 interfering with tumor growth, invasion, metastasis and angiogenesis.

Suppression of metastasis of human pancreatic cancer to the liver by transportal injection of recombinant adenoviral NK4 in nude mice

NK4, a 4-kringle fragment of hepatocyte growth factor (HGF), is an HGF antagonist that also acts as an angiogenesis inhibitor. NK4 strongly inhibits the infiltration, metastasis, and tumor growth of pancreatic cancer. The aim of our study was to evaluate the antitumor effect of adenovirus-mediated NK4 gene transfer to the liver on hepatic metastasis of pancreatic cancer in vivo. We constructed recombinant adenoviral NK4 (Ad-NK4), which encodes a secreted form of human NK4. Intrasplenic injection of Ad-NK4 induced high and relatively maintained expression of NK4 protein in the liver and suppressed the number and growth of metastatic foci in the liver in a nude mouse model. Microscopically, central necrosis was found even in small metastatic foci in Ad-NK4 treated mice. Immunohistochemical analysis of metastatic tumors showed a remarkable decrease in microvessel density and an increase in the number of apoptotic tumor cells after treatment with Ad-NK4. These results indicate that intraportal injection of Ad-NK4 may be a useful therapeutic modality for the clinical control of hepatic metastasis in pancreatic cancer.

Mechanisms and significance of bifunctional NK4 in cancer treatment

Based on the background that hepatocyte growth factor (HGF) and c-Met/HGF receptor tyrosine kinase play a definite role in tumor invasion and metastasis, NK4, four-kringles containing intramolecular fragment of HGF, was isolated as a competitive antagonist for the HGF-c-Met system. Independent of its HGF-antagonist action, NK4 inhibited angiogenesis induced by vascular endothelial cell growth factor and basic fibroblast growth factor, as well as HGF, indicating that NK4 is a bifunctional molecule that acts as an HGF-antagonist and angiogenesis inhibitor. Interestingly, kringle domains in distinct types of proteins, e.g., plasminogen, prothrombin, plasminogen activators, apolipoprotein(a), and HGF, share angioinhibitory actions. In experimental models of distinct types of cancers, NK4 protein administration or NK4 gene therapy inhibited tumor invasion, metastasis, and angiogenesis-dependent tumor growth. Cancer treatment with NK4 may prove to suppress malignant tumors to be 'static' in both tumor growth and spreading, as based on biological characteristics of malignant tumors.