Expression of Cadherin-17 Promotes Metastasis in a Highly Bone Marrow Metastatic Murine Breast Cancer Model

Animal Models of Metastatic Lesions to the Spine: a Focus on Epidural Spinal Cord Compression

Epidural spinal cord compression (ESCC) secondary to spine metastases is one of the most devastating sequelae of primary cancer as it may lead to muscle weakness, paresthesia, pain, and paralysis. Spine metastases occur through a multi-step process that can result in eventual ESCC; however, the lack of a preclinical model to effectively recapitulate each step of this metastatic cascade and the symptom burden of ESCC has limited our understanding of this disease process. In this review, we discuss animal models that best recapitulate ESCC; we start with a broad discussion of commonly used models of bone metastasis and end with a focused discussion of models used to specifically study ESCC. Orthotopic models offer the most authentic recapitulation of metastasis development; however, they rarely result in symptomatic ESCC and are challenging to replicate. Conversely, models that involve injection of tumor cells directly into the bloodstream or bone better mimic the symptoms of ESCC; however, they provide limited insight into the epithelial to mesenchymal transition (EMT) and natural hematogenous spread of tumor cell. Therefore, until an ideal model is created, it is critical to select an animal model that is specifically designed to answer the scientific question of interest.

Study on Cancer Cell Invasiveness via Application of Mechanical Force to Induce Chloride Ion Efflux

Chloride channels regulate cell volume by an efflux of chloride ions in response to osmotic stresses. These have been shown to play a role in cancer invasion. However, their function in cancer metastasis remains unclear. As the internal environment of the human body is rarely exposed to osmotic stress, we presumed that Cl^- efflux in cancer cells is induced by mechanical stress caused by their crowded environment and invasion of their narrow interstitial spaces. In this study, we recruited atomic force microscopy to apply mechanical stress to mouse or human breast cancer cells with varying degrees of malignancy and examined their Cl^- efflux by N-ethoxycarbonylmethyl-6-methoxyquinolinium bromide (MQAE), which is quenched via collision with Cl^- ions. We found that intracellular MQAE fluorescence intensity increased immediately after cell compression, demonstrating induction of Cl^- efflux by mechanical force. Furthermore, Cl^- efflux ability showed correlation with the cancer metastatic potential. These results suggested that mechanical stress induced Cl^- efflux may serve as a potential reporter for estimating the invasion ability of cancer cells.

Mechanical Property Changes in Breast Cancer Cells Induced by Stimulation with Macrophage Secretions in Vitro

The contribution of secretions from tumor-associated macrophage (TAM)-like cells to the stimulation of mechanical property changes in murine breast cancer cells was studied using an in vitro model system. A murine breast cancer cell line (FP10SC2) was stimulated by adding macrophage (J774.2) cultivation medium containing stimulation molecules secreted from the macrophages, and changes in mechanical properties were compared before and after stimulation. As a result, cell elasticity decreased, degradation ability of the extracellular matrix increased, and the expression of plakoglobin was upregulated. These results indicate that cancer cell malignancy is upregulated by this stimulation. Moreover, changes in intercellular adhesion strengths between pairs of cancer cells were measured before and after stimulation using atomic force microscopy (AFM). The maximum force required to separate cells was increased by stimulation with the secreted factors. These results indicate the possibility that TAMs cause changes in the mechanical properties of cancer cells in tumor microenvironments, and in vitro measurements of mechanical property changes in cancer cells will be useful to study interactions between cells in tumor microenvironments.

Direct Delivery of Cas9-sgRNA Ribonucleoproteins into Cells Using a Nanoneedle Array

The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a powerful and widely used tool for genome editing. Recently, it was reported that direct delivery of Cas9-sgRNA ribonucleoproteins (RNPs) reduced off-target effects. Therefore, non-invasive, high-throughput methods are needed for direct delivery of RNPs into cells. Here, we report a novel method for direct delivery of RNPs into cells using a nanostructure with a high-aspect-ratio and uniform nanoneedles. This nanostructure is composed of tens of thousands of nanoneedles laid across a 2D array. Through insertion of the nanoneedle array previously adsorbed with Cas9-sgRNA, it was possible to deliver RNPs directly into mammalian cells for genome editing.

The Structural Function of Nestin in Cell Body Softening is Correlated with Cancer Cell Metastasis

Intermediate filaments play significant roles in governing cell stiffness and invasive ability. Nestin is a type VI intermediate filament protein that is highly expressed in several high-metastatic cancer cells. Although inhibition of nestin expression was shown to reduce the metastatic capacity of tumor cells, the relationship between this protein and the mechanism of cancer cell metastasis remains unclear. Here, we show that nestin softens the cell body of the highly metastatic mouse breast cancer cell line FP10SC2, thereby enhancing the metastasis capacity. Proximity ligation assay demonstrated increased binding between actin and vimentin in nestin knockout cells. Because nestin copolymerizes with vimentin and nestin has an extremely long tail domain in its C-terminal region, we hypothesized that the tail domain functions as a steric inhibitor of the vimentin-actin interaction and suppresses association of vimentin filaments with the cortical actin cytoskeleton, leading to reduced cell stiffness. To demonstrate this function, we mechanically pulled vimentin filaments in living cells using a nanoneedle modified with vimentin-specific antibodies under manipulation by atomic force microscopy (AFM). The tensile test revealed that mobility of vimentin filaments was increased by nestin expression in FP10SC2 cells.

Determination of Cadherin-17 in Tumor Tissues of Different Metastatic Grade Using a Single Incubation-Step Amperometric Immunosensor

This paper reports the development of an amperometric immunosensing platform for the determination of cadherin-17 (CDH-17), an atypical adhesion protein involved in the progression, metastatic potential, and survival of high prevalence gastric, hepatocellular, and colorectal tumors. The methodology developed relies on the efficient capture and enzymatic labeling of the target protein on the magnetic microparticles (MBs) surface using commercial antibodies and amperometric transduction at screen-printed carbon electrodes (SCPEs) through the HRP/H₂O₂/HQ system. The developed immunosensing platform allows the selective determination of the target protein at low ng mL^-1 level (LOD of 1.43 ng mL^-1) in 45 min and using a single incubation step. The electrochemical immunosensor was successfully used for the accurate determination of the target protein in a small amount (0.5 μg) of raw lysates of colon cancer cells with different metastatic potential as well as in extracts from paraffin embedded cancer colon tissues of different metastatic grade.

A genome editing vector that enables easy selection and identification of knockout cells

The CRISPR/Cas9 system is a powerful genome editing tool for disrupting the expression of specific genes in a variety of cells. However, the genome editing procedure using currently available vectors is laborious, and there is room for improvement to obtain knockout cells more efficiently. Therefore, we constructed a novel vector for high efficiency genome editing, named pGedit, which contains EGFP-Bsr as a selection marker, expression units of Cas9, and sgRNA without a terminator sequence of the U6 promoter. EGFP-Bsr is a fusion protein of EGFP and blasticidin S deaminase, and enables rapid selection and monitoring of transformants, as well as confirmation that the vector has not been integrated into the genome. By using pGedit, we targeted human ACTB, ACTG1 and mouse Nes genes coding for β-actin, γ-actin and nestin, respectively. Knockout cell lines of each gene were easily and efficiently obtained in all three cases. In this report, we show that our novel vector, pGedit, significantly facilitates genome editing.

In vitro and in vivo anti-tumor effects of selected platinum(IV) and dinuclear platinum(II) complexes against lung cancer cells

In the present study, cytotoxic effects of cisplatin, the most usually used chemotherapeutic agent, were compared with new designed platinum(IV) ([PtCl₄(en)] (en = ethylenediamine) and [PtCl₄(dach)]) (dach = (±)-trans-1,2-diaminocyclohexane) and platinum(II) complexes ([{trans-Pt(NH₃)₂Cl}₂(μ-pyrazine)](ClO₄)₂ (Pt1), [{trans-Pt(NH₃)₂Cl}₂(μ-4,4'-bipyridyl)](ClO₄)₂DMF(Pt2),[{trans-Pt(NH₃)₂Cl}₂(μ-1,2-bis(4pyridyl)ethane)](ClO₄)₂ (Pt3)), in vitro and in vivo against human and murine lung cancer cells, to determine anti-tumor potential of newly synthesized platinum-based drugs in the therapy of lung cancer. Results obtained by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], Lactate dehydrogenase and Annexin V/Propidium Iodide assays showed that, among all tested complexes, [PtCl₄(en)] had the highest cytotoxicity against human and murine lung carcinoma cells in vitro. [PtCl₄(en)] showed significantly higher cytotoxicity then cisplatin in all tested concentrations, mainly by inducing apoptosis in lung cancer cells. [PtCl₄(en)] was well tolerated in vivo. Clinical signs of [PtCl₄(en)]-induced toxicity, such as changes in food, water consumption or body weight, nephrotoxicity or hepatotoxicity was not observed in [PtCl₄(en)]-treated mice. [PtCl₄(en)] managed to increase presence of CD45+ leukocytes, including F4/80+ macrophages, CD11c+ dendritic cells, CD4+ helper and CD8+ cytotoxic T cells (CTLs) in the lungs, cytotoxic NK, NKT and CTLs in the spleens of tumor bearing mice, resulting with reduction of metastatic lesions in the lungs, indicating its potential to stimulate anti-tumor immune response in vivo. Due to its anti-tumor cytotoxicity, biocompatibility, and potential for stimulation of anti-tumor immune response, [PtCl₄(en)] may be a good candidate for further testing in the field of medicinal chemistry.