Characterization of five newly derived canine osteosarcoma cell lines

Investigating cell death responses associated with histotripsy ablation of canine osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most frequently occurring primary bone tumor in dogs and people and innovative treatment options are profoundly needed. Histotripsy is an emerging tumor ablation modality, and it is essential for the clinical translation of histotripsy to gain knowledge about the outcome of nonablated tumor cells that could remain postablation. The objective of this study was to characterize the cell death genetic signature and proliferation response of canine OS cells post a near complete histotripsy ablation (96% ± 1.5) and to evaluate genetic cell death signatures associated with histotripsy ablation and OS in vivo.

METHODS

In the current study, we ablated three canine OS cell lines with a histotripsy dose that resulted in near complete ablation to allow for a viable tumor cell population for downstream analyses. To assess the in vivo cell death genetic signature, we characterized cell death genetic signature in histotripsy-ablated canine OS tumors collected 24-h postablation.

RESULTS

Differential gene expression changes observed in the 4% viable D17 and D418 cells, and histotripsy-ablated OS tumor samples, but not in Abrams cells, were associated with immunogenic cell death (ICD). The 4% viable OS cells demonstrated significantly reduced proliferation, compared to control OS cells, in vitro.

CONCLUSION

Histotripsy ablation of OS cell lines leads to direct and potentially indirect cell death as evident by, reduced proliferation in remaining viable OS cells and cell death genetic signatures suggestive of ICD both in vitro and in vivo.

Isolation and Characterization of Novel Canine Osteosarcoma Cell Lines from Chemotherapy-Naïve Patients

The present study aimed to establish novel canine osteosarcoma cell lines (COS3600, COS3600B, COS4074) and characterize the recently described COS4288 cells. The established D-17 cell line served as a reference. Analyzed cell lines differed notably in their biological characteristics. Calculated doubling times were between 22 h for COS3600B and 426 h for COS4074 cells. COS3600B and COS4288 cells produced visible colonies after anchorage-independent growth in soft agar. COS4288 cells were identified as cells with the highest migratory capacity. All cells displayed the ability to invade through an artificial basement membrane matrix. Immunohistochemical analyses revealed the mesenchymal origin of all COS cell lines as well as positive staining for the osteosarcoma-relevant proteins alkaline phosphatase and karyopherin α2. Expression of p53 was confirmed in all tested cell lines. Gene expression analyses of selected genes linked to cellular immune checkpoints (CD270, CD274, CD276), kinase activity (MET, ERBB2), and metastatic potential (MMP-2, MMP-9) as well as selected long non-coding RNA (MALAT1) and microRNAs (miR-9, miR-34a, miR-93) are provided. All tested cell lines were able to grow as multicellular spheroids. In all spheroids except COS4288, calcium deposition was detected by von Kossa staining. We believe that these new cell lines serve as useful biological models for future studies.

The genomic landscape of canine osteosarcoma cell lines reveals conserved structural complexity and pathway alterations

The characterization of immortalized canine osteosarcoma (OS) cell lines used for research has historically been based on phenotypic features such as cellular morphology and expression of bone specific markers. With the increasing use of these cell lines to investigate novel therapeutic approaches prior to in vivo translation, a much more detailed understanding regarding the genomic landscape of these lines is required to ensure accurate interpretation of findings. Here we report the first whole genome characterization of eight canine OS cell lines, including single nucleotide variants, copy number variants and other structural variants. Many alterations previously characterized in primary canine OS tissue were observed in these cell lines, including TP53 mutations, MYC copy number gains, loss of CDKN2A, PTEN, DLG2, MAGI2, and RB1 and structural variants involving SETD2, DLG2 and DMD. These data provide a new framework for understanding how best to incorporate in vitro findings generated using these cell lines into the design of future clinical studies involving dogs with spontaneous OS.

The use of alkaline phosphatase and runx2 to distinguish osteosarcoma from other common malignant primary bone tumors in dogs

In dogs, primary bone tumors can be difficult to distinguish with histopathology. Of those tumors, osteosarcoma (OSA) is the most common and aggressive. In this study, 4 immunohistochemistry markers-alkaline phosphatase (ALP), osteonectin (ON), osteopontin (OP), and runx2-were evaluated for their ability to distinguish OSA from other primary bone tumors. The 42 formalin-fixed, paraffin-embedded, primary canine bone tumors included 15 OSAs, 8 chondrosarcomas, 11 fibrosarcomas, and 8 histiocytic sarcomas. All 4 antibodies were highly sensitive for detection of osteosarcoma. ALP was the most sensitive at 100% and runx2 the most specific at 78%. Running ALP and runx2 in series resulted in a sensitivity of 87% and a specificity of 85%. This combination of immunomarkers resulted in a diagnostic panel for distinguishing osteosarcoma from other primary bone tumors.

Canine and murine models of osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor in children. Despite efforts to develop and implement new therapies, patient outcomes have not measurably improved since the 1980s. Metastasis continues to be the main source of patient mortality, with 30% of cases developing metastatic disease within 5 years of diagnosis. Research models are critical in the advancement of cancer research and include a variety of species. For example, xenograft and patient-derived xenograft (PDX) mouse models provide opportunities to study human tumor cells in vivo while transgenic models have offered significant insight into the molecular mechanisms underlying OS development. A growing recognition of naturally occurring cancers in companion species has led to new insights into how veterinary patients can contribute to studies of cancer biology and drug development. The study of canine cases, including the use of diagnostic tissue archives and clinical trials, offers a potential mechanism to further canine and human cancer research. Advancement in the field of OS research requires continued development and appropriate use of animal models. In this review, animal models of OS are described with a focus on the mouse and tumor-bearing pet dog as parallel and complementary models of human OS.

Cytotoxicity of an Innovative Pressurised Cyclic Solid-Liquid (PCSL) Extract from Artemisia annua

Therapeutic treatments with Artemisia annua have a long-established tradition in various diseases due to its antibacterial, antioxidant, antiviral, anti-malaria and anti-cancer effects. However, in relation to the latter, virtually all reports focused on toxic effects of A. annua extracts were obtained mostly through conventional maceration methods. In the present study, an innovative extraction procedure from A. annua, based on pressurised cyclic solid–liquid (PCSL) extraction, resulted in the production of a new phytocomplex with enhanced anti-cancer properties. This extraction procedure generated a pressure gradient due to compressions and following decompressions, allowing to directly perform the extraction without any maceration. The toxic effects of A. annua PCSL extract were tested on different cells, including three cancer cell lines. The results of this study clearly indicate that the exposure of human, murine and canine cancer cells to serial dilutions of PCSL extract resulted in higher toxicity and stronger propensity to induce apoptosis than that detected by subjecting the same cells to Artemisia extracts obtained through canonical extraction by maceration. Collected data suggest that PCSL extract of A. annua could be a promising and economic new therapeutic tool to treat human and animal tumours.

Enhanced expression of cyclooxygenase-2 related multi-drug resistance gene in melanoma and osteosarcoma cell lines by TSG-6 secreted from canine adipose-derived mesenchymal stem/stromal cells

BACKGROUND

Multiple drug resistance (MDR) of cancer cells is the main cause of intrinsic or acquired desensitization to chemotherapy in many cancers. A number of studies have found high expression of COX-2 to be a factor for expression of MDR gene in several cancer. Furthermore, adipose tissue derived mesenchymal stem/stromal cells (ADSC) have been found to increase cyclo-oxygenase-2 (COX-2) expression in some tumour cells. The mechanism for this, however, is not yet clear and needs further study.

OBJECTIVE

The purpose of this study was to determine whether tumour necrosis factor-alpha stimulated gene/protein 6 (TSG-6) secreted from ADSCs is associated with an increase in MDR genes by inducing COX-2 gene expression in melanoma and osteosarcoma cell lines.

METHODS

ADSCs were transfected with TSG-6 siRNA or Control RNA respected, and cancer cell line were transfected with COX-2 siRNA or Control RNA respected. Using trans well coculture system, the interactions of ADSCs with tumour cells were investigated.

RESULTS

Increased COX-2 expression was observed in cancer cell co-cultured with ADSCs. Additionally, we identified that COX-2 expression was related to drug resistance genes (P-glycoprotein, multidrug resistance-associated protein). Transfecting canine ADSCs with small interfering RNA, TSG-6 secreted from ADSCs was found to be a major factor in the regulation of COX-2 expression and drug resistance genes in osteosarcoma and melanoma cell lines.

CONCLUSION

TSG-6 mediated COX-2 up-regulation is a possible mechanism of chemoresistance development induced by ADSCs. These findings provide better understanding about the mechanism associated with ADSC-induced chemoresistance in cancer.

Beyond tradition and convention: benefits of non-traditional model organisms in cancer research

Traditional laboratory model organisms are indispensable for cancer research and have provided insight into numerous mechanisms that contribute to cancer development and progression in humans. However, these models do have some limitations, most notably related to successful drug translation, because traditional model organisms are often short-lived, small-bodied, genetically homogeneous, often immunocompromised, are not exposed to natural environments shared with humans, and usually do not develop cancer spontaneously. We propose that assimilating information from a variety of long-lived, large, genetically diverse, and immunocompetent species that live in natural environments and do develop cancer spontaneously (or do not develop cancer at all) will lead to a more comprehensive understanding of human cancers. These non-traditional model organisms can also serve as sentinels for environmental risk factors that contribute to human cancers. Ultimately, expanding the range of animal models that can be used to study cancer will lead to improved insights into cancer development, progression and metastasis, tumor microenvironment, as well as improved therapies and diagnostics, and will consequently reduce the negative impacts of the wide variety of cancers afflicting humans overall.