In vivo growth suppression of CT-26 mouse colorectal cancer cells by adenovirus-expressed small hairpin RNA specifically targeting thymosin beta-4 mRNA. Cancer Gene Ther. 2014;21:389-396. [PMID: 25124811 DOI: 10.1038/cgt.2014.43]

Vactosertib potently improves anti-tumor properties of 5-FU for colon cancer

BACKGROUND

Several studies have shown that the TGF-β signaling pathway plays a critical role in colorectal cancer (CRC) pathogenesis. The aim of the current study is to investigate the therapeutic potential of Vactosertib (EW-7197), a selective inhibitor of TGF-β receptor type I, either alone or in combination with the standard first-line chemotherapeutic treatment, 5-Fluorouracil (5-FU), in CRC progression in both cellular and animal models.

METHODS

Real-Time PCR, Zymography, enzyme-linked immunosorbent assay (ELISA), Hematoxylin and Eosin (H&E) tissue staining, and Flow cytometry techniques were applied to determine the anti-tumor properties of this novel TGF-β inhibitor in in vitro (CT-26 cell line) and in vivo (inbred BALB/C mice) samples.

RESULTS

Our findings showed that Vactosertib decreased cell proliferation and induced spheroid shrinkage. Moreover, this inhibitor suppressed the cell cycle and its administration either alone or in combination with 5-FU induced apoptosis by regulating the expression of p53 and BAX proteins. It also improved 5-FU anti-cancer effects by decreasing the tumor volume and weight, increasing tumor necrosis, and regulating tumor fibrosis and inflammation in an animal model. Vactosertib also enhanced the inhibitory effect of 5-FU on invasive behavior of CRC cells by upregulating the expression of E-cadherin and inhibiting MMP-9 enzymatic activity.

CONCLUSION

This study demonstrating the potent anti-tumor effects of Vactosertib against CRC progression. Our results clearly suggest that this inhibitor could be a promising agent reducing CRC tumor progression when administered either alone or in combination with standard treatment in CRC patients.

Neoadjuvant Gold Nanoshell-Based Photothermal Therapy Combined with Liposomal Doxorubicin in a Mouse Model of Colorectal Cancer

Introduction

Traditional cancer treatments, such as chemotherapy, are often incapable of achieving complete responses as standalone therapies. Hence, current treatment strategies typically rely on a combination of several approaches. Nanoparticle-based photothermal therapy (PTT) is a technique used to kill cancer cells through localized, severe hyperthermia that has shown promise as an add-on treatment to multiple cancer therapies. Here, we evaluated whether the combination of gold nanoshell (NS)-based PTT and liposomal doxorubicin could improve outcome in a mouse model of colorectal cancer.

Methods

First, NS-based PTT was performed on tumor-bearing mice. Radiolabeled liposomes were then injected at different timepoints to follow their accumulation in the tumor and determine the ideal injection time after PTT. In addition, fluorescent liposomes were used to observe the liposomal distribution in the tumor after PTT. Finally, we combined PTT and doxorubicin-loaded liposomes and studied the effect of the treatment strategy on the mice by following tumor growth and survival.

Results

PTT significantly improved liposomal accumulation in the tumor, but only when the liposomes were injected immediately after the therapy. The liposomes accumulated mostly in regions adjacent to the ablated areas. When PTT was combined with liposomal doxorubicin, the mice experienced a slowdown in tumor growth and an improvement in survival.

Conclusion

According to our preclinical study, NS-based PTT seems promising as an add-on treatment for liposomal chemotherapy and potentially other systemic therapies, and could be relevant for future application in a clinical setting.

Toll-like receptor 4 is a master regulator for colorectal cancer growth under high-fat diet by programming cancer metabolism

Although high-fat diet (HFD) has been implicated in the development of colorectal cancer (CRC), the critical signaling molecule that mediates the cancer growth is not well-defined. Identifying the master regulator that controls CRC growth under HFD can facilitate the development of effective therapeutics for the cancer treatment. In this study, the global lipidomics and RNA sequencing data show that, in the tumor tissues of CRC-bearing mouse models, HFD not only increases tumor weight, but also the palmitic acid level and TLR4 expression, which are reduced when HFD is replaced by control diet. These concomitant changes suggest the roles of palmitic acid and TLR4 in CRC growth. Subsequent studies show that palmitic acid regulates TLR4 expression in PU.1-dependent manner. Knockdown of PU.1 or mutations of PU.1-binding site on TLR4 promoter abolish the palmitic acid-increased TLR4 expression. The role of palmitic acid/PU.1/TLR4 axis in CRC growth is further examined in cell model and animal models that are fed either HFD or palmitic acid-rich diet. More importantly, iTRAQ proteomics data show that knockdown of TLR4 changes the metabolic enzyme profiles in the tumor tissues, which completely abolish the HFD-enhanced ATP production and cancer growth. Our data clearly demonstrate that TLR4 is a master regulator for CRC growth under HFD by programming cancer metabolism.

Improving miRNA Delivery by Optimizing miRNA Expression Cassettes in Diverse Virus Vectors

The RNA interference pathway is an evolutionary conserved post-transcriptional gene regulation mechanism that is exclusively triggered by double-stranded RNA inducers. RNAi-based methods and technologies have facilitated the discovery of many basic science findings and spurred the development of novel RNA therapeutics. Transient induction of RNAi via transfection of synthetic small interfering RNAs can trigger the selective knockdown of a target mRNA. For durable silencing of gene expression, either artificial short hairpin RNA or microRNA encoding transgene constructs were developed. These miRNAs are based on the molecules that induce the natural RNAi pathway in mammals and humans: the endogenously expressed miRNAs. Significant efforts focused on the construction and delivery of miRNA cassettes in order to solve basic biology questions or to design new therapy strategies. Several viral vectors have been developed, which are particularly useful for the delivery of miRNA expression cassettes to specific target cells. Each vector system has its own unique set of distinct properties. Thus, depending on the specific application, a particular vector may be most suitable. This field was previously reviewed for different viral vector systems, and now the recent progress in the field of miRNA-based gene-silencing approaches using lentiviral vectors is reported. The focus is on the unique properties and respective limitations of the available vector systems for miRNA delivery.

Phytochemical Inhibition of Multidrug Resistance Protein-1 as a Therapeutic Strategy for Hemangioendothelioma

AIMS

Hemangiomas are endothelial cell tumors and the most common soft tissue tumors in infants. They frequently cause deformity and can cause death. Current pharmacologic therapies have high-risk side-effect profiles, which limit the number of children who receive treatment. The objectives of this work were to identify the mechanisms through which standardized berry extracts can inhibit endothelial cell tumor growth and test these findings in vivo.

RESULTS

EOMA cells are a validated model that generates endothelial cell tumors when injected subcutaneously into syngeneic (129P/3) mice. EOMA cells treated with a blend of powdered natural berry extracts (NBE) significantly inhibited activity of multidrug resistance protein-1 (MRP-1) compared to vehicle controls. This resulted in nuclear accumulation of oxidized glutathione (GSSG) and apoptotic EOMA cell death. When NBE-treated EOMA cells were injected into mice, they generated smaller tumors and had a higher incidence of apoptotic cell death compared to vehicle-treated EOMA cells as demonstrated by immunocytochemistry. Kaplan-Meier survival curves for tumor-bearing mice showed that NBE treatment significantly prolonged survival compared to vehicle-treated controls.

INNOVATION

These are the first reported results to show that berry extracts can inhibit MRP-1 function that causes apoptotic tumor cell death by accumulation of GSSG in the nucleus of EOMA cells where NADPH oxidase is hyperactive and causes pathological angiogenesis.

CONCLUSIONS

These findings indicate that berry extract inhibition of MRP-1 merits consideration and further investigation as a therapeutic intervention and may have application for other cancers with elevated MRP-1 activity. Antioxid. Redox Signal. 26, 1009-1019.

Recombinant adeno-associated virus carrying thymosin β4 suppresses experimental colitis in mice

AIM

To investigate the protective effect of a recombinant adeno-associated virus carrying thymosin β₄ (AAV-Tβ₄) on murine colitis via intracolonic administration.

METHODS

AAV-Tβ₄ was prepared and intracolonically used to mediate the secretory expression of Tβ₄ in mouse colons. Dextran sulfate sodium (DSS) was applied to induce the murine ulcerative colitis, and 2,4,6-trinitrobenzene sulfonic acid (TNBS) was used to establish a mouse colitis model resembling Crohn’s disease. The disease severity and colon injuries were observed and graded to reveal the effects of AAV-Tβ₄ on colitis. The activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) and the content of malondialdehyde (MDA) were determined using biochemical assays. Colonic levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-10 were measured using ELISA, and mucosal epithelial cell apoptosis and proliferation were detected by TUNEL assay and immunochemistry, respectively.

RESULTS

Recombinant AAVs efficiently delivered LacZ and Tβ₄ into the colonic tissues of the mice, and AAV-Tβ₄ led to a strong expression of Tβ₄ in mouse colons. In both the DSS and TNBS colitis models, AAV-Tβ₄-treated mice displayed distinctly attenuated colon injuries and reduced apoptosis rate of colonic mucosal epithelia. AAV-Tβ₄ significantly reduced inflammatory cell infiltrations and relieved oxidative stress in the inflamed colons of the mice, as evidenced by decreases in MPO activity and MDA content and increases in SOD activity. AAV-Tβ₄ also modulated colonic TNF-α, IL-1β and IL-10 levels and suppressed the compensatory proliferation of colonic epithelial cells in DSS- and TNBS-treated mice.

CONCLUSION

Tβ₄ exerts a protective effect on murine colitis, indicating that AAV-Tβ₄ could potentially be developed into a promising agent for the therapy of inflammatory bowel diseases.