Medium-Throughput Drug- and Radiotherapy Screening Assay using Patient-Derived Organoids

Patient-derived organoid (PDO) models allow for long-term expansion and maintenance of primary epithelial cells grown in three dimensions and a ...

Utrecht University

Intermittent claudication in an Afghan hound due to aortic arteriosclerosis.

Acquired portosystemic shunting in 2 cats secondary to congenital hepatic fibrosis.

Chemotherapy protocols for canine lymphoma include the routine use of glucocorticoids for their lympholytic effect. However, glucocorticoids are associated with side effects (e.g. polyphagia, polyuria, and weight gain), limit the use of non-steroidal anti-inflammatory drugs, and can induce drug transporter expression that could lead to drug resistance. Despite these negative effects, there are no data to support the use of glucocorticoids as part of a multidrug chemotherapy protocol for the treatment of canine lymphoma. A prospective, randomized clinical trial was conducted in 81 dogs with multicentric lymphoma and no history of recent glucocorticoid use. All dogs were staged and treated with the same chemotherapy protocol (L-asparaginase, cyclophosphamide, doxorubicin, vincristine, and prednisolone) with half of the dogs receiving prednisolone. Both treatment groups were similar with respect to demographics, immunophenotype, and clinical stage, except for a higher number of substage b patients in the prednisolone group (5 vs. 14; P=0.015). Treatment results obtained with the initial treatment (complete response rate 75%, disease-free period 176 days) and rescue treatment (complete response rate 45%, disease-free period 133 days), overall survival (283 days) and adverse events (number and grade) were similar for both groups. In conclusion, prednisolone, as part of a multidrug chemotherapy protocol, has no additional effect on treatment results and can be omitted from first-line multidrug protocols used for the treatment of canine lymphoma.

Prednisolone inclusion in a first-line multidrug cytostatic protocol for the treatment of canine lymphoma does not affect therapy results.

Canine lymphoma is routinely treated with a doxorubicin-based multidrug chemotherapy protocol, and although treatment is initially successful, tumor recurrence is common and associated with therapy resistance. Active efflux of chemotherapeutic agents by transporter proteins of the ATP-Binding Cassette superfamily forms an effective cellular defense mechanism and a high expression of these transporters is frequently observed in chemotherapy-resistant tumors in both humans and dogs. In this study we describe the ABC-transporter expression in a canine lymphoid cell line and a sub-cell line with acquired drug resistance following prolonged exposure to doxorubicin. This sub-cell line was more resistant to doxorubicin and vincristine, but not to prednisolone, and had a highly increased P-glycoprotein (P-gp/abcb1) expression and transport capacity for the P-gp model-substrate rhodamine123. Both resistance to doxorubicin and vincristine, and rhodamine123 transport capacity were fully reversed by the P-gp inhibitor PSC833. No changes were observed in the expression and function of the ABC-transporters MRP-1 and BCRP. It is concluded that GL-40 cells represent a useful model for studying P-gp dependent drug resistance in canine lymphoid neoplasia, and that this model can be used for screening substances as potential P-gp substrates and their capacity to modulate P-gp mediated drug resistance.

Multi-drug resistance in a canine lymphoid cell line due to increased P-glycoprotein expression, a potential model for drug-resistant canine lymphoma.

Canine lymphoma is typically treated with a doxorubicin-based multidrug chemotherapy protocol. Although this is often initially successful, tumour recurrence is common and frequently refractory to treatment. Failure to respond to chemotherapy is thought to represent drug resistance and has been associated with active efflux of cytostatic drugs by transporter proteins of the ATP-binding cassette (ABC) family, including P-glycoprotein (ABCB1), MRP1 (ABCC1) and BCRP (ABCG2). In this study, ABC transporter mRNA expression was assessed in 63 dogs diagnosed with multicentric lymphoma that were treated with a doxorubicin-based chemotherapy protocol. Expression of ABCB1, ABCB5, ABCB8, ABCC1, ABCC3, ABCC5 and ABCG2 mRNA was quantified in tumour samples (n = 107) obtained at the time of diagnosis, at first tumour relapse and when the tumour was no longer responsive to cytostatic drugs while receiving chemotherapy. Expression data were related to patient demographics, staging, treatment response and drug resistance (absent, intrinsic, acquired). ABC transporter expression was independent of sex, weight, age, stage or substage, but T cell lymphoma and hypercalcaemia were associated with increased ABCB5 and ABCC5 expression, and decreased ABCC1 mRNA expression. Drug resistance occurred in 35/63 (55.6%) dogs and was associated with increased ABCB1 mRNA expression in a subset of dogs with B cell lymphoma, and with increased ABCG2 and decreased ABCB8, ABCC1 and ABCC3 mRNA expression in T cell lymphomas. ABC transporter expression in the pre-treatment sample was not predictive of the length of the first disease-free period or overall survival. Glucocorticoids had no effect on ABC transporter mRNA expression. In conclusion, drug resistance in canine multicentric lymphoma is an important cause of treatment failure and is associated with upregulation of ABCB1 and ABCG2 mRNA.

A longitudinal study of ABC transporter expression in canine multicentric lymphoma.

Drug resistance (DR) is  major limiting factor in the successful treatment of systemic neoplasia with cytotoxic chemotherapy. DR can be either intrinsic or acquired, and although the development and clinical implications are different, the underlying mechanisms are likely to be similar. Most causes for DR are pharmacodynamic in nature, result from adaptations within the tumor cell and include reduced drug uptake, increased drug efflux, changes in drug metabolism or drug target, increased capacity to repair drug-induced DNA damage or increased resistance to apoptosis. The role of active drug efflux transporters, and those of the ABC-transporter family in particular, have been studied extensively in human oncology and to a lesser extent in veterinary medicine. Methods reported to assess ABC-transporter status include detection of the actual protein (Western blot, immunohistochemistry), mRNA or ABC-transporter function. The three major ABC-transporters associated with DR in human oncology are ABCB1 or P-gp, ABCC1 or MRP1, and ABCG2 or BCRP, and have been demonstrated in canine cell lines, healthy dogs and dogs with cancer. Although this supports a causative role for these ABC-transporters in DR cytotoxic agents in the dog, the relative contribution to the clinical phenotype of DR in canine cancer remains an area of debate and requires further prospective studies.

Mechanisms of Drug Resistance in Veterinary Oncology- A Review with an Emphasis on Canine Lymphoma.

To increase the efficacy of chemoradiation and decrease its toxicity in normal tissue, a new concept is proposed, local radiosensitizer delivery, which combines triggered release of a radiosensitizer from thermosensitive liposomes with local hyperthermia and radiotherapy. Here, key aspects of this concept were investigated in vitro I) the effect of hyperthermia on the enhancement of radiotherapy by ThermoDox (thermosensitive liposome containing doxorubicin), II) the concentration dependence of the radiosensitizing effect of doxorubicin and III) the sequence of doxorubicin, hyperthermia and radiotherapy maximizing the radiosensitizing effect.

Triggered radiosensitizer delivery using thermosensitive liposomes and hyperthermia improves efficacy of radiotherapy: An in vitro proof of concept study.

Previous studies have described that tumor organoids can capture the diversity of defined human carcinoma types. Here, we describe conditions for long-term culture of human mucosal organoids. Using this protocol, a panel of 31 head and neck squamous cell carcinoma (HNSCC)-derived organoid lines was established. This panel recapitulates genetic and molecular characteristics previously described for HNSCC. Organoids retain their tumorigenic potential upon xenotransplantation. We observe differential responses to a panel of drugs including cisplatin, carboplatin, cetuximab, and radiotherapy . Additionally, drug screens reveal selective sensitivity to targeted drugs that are not normally used in the treatment of patients with HNSCC. These observations may inspire a personalized approach to the management of HNSCC and expand the repertoire of HNSCC drugs. SIGNIFICANCE: This work describes the culture of organoids derived from HNSCC and corresponding normal epithelium. These tumoroids recapitulate the disease genetically, histologically, and functionally.  drug screening of tumoroids reveals responses to therapies both currently used in the treatment of HNSCC and those not (yet) used in clinical practice...

Maurice M. J. M. Zandvliet

Department of Clinical Sciences - Companion Animals,
Faculty of Veterinary Medicine,
Department of Clinical Sciences - Companion Animals, Faculty of Veterinary Medicine

Utrecht University

Medium-Throughput Drug- and Radiotherapy Screening Assay using Patient-Derived Organoids

Maurice M. J. M. Zandvliet

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Clinical Sciences - Companion Animals,Faculty of Veterinary Medicine,Department of Clinical Sciences - Companion Animals, Faculty of Veterinary Medicine

Utrecht University

Medium-Throughput Drug- and Radiotherapy Screening Assay using Patient-Derived Organoids

Department of Clinical Sciences - Companion Animals,
Faculty of Veterinary Medicine,
Department of Clinical Sciences - Companion Animals, Faculty of Veterinary Medicine