Orthotopic and heterotopic murine models of pancreatic cancer and their different responses to FOLFIRINOX chemotherapy

Abstract

Syngeneic, immunocompetent allograft tumor models recapitulate important aspects of the tumor microenvironment and have short tumor latency with predictable growth kinetics, making them useful for trialing novel therapeutics. Here, we describe surgical techniques for orthotopic and heterotopic pancreatic ductal adenocarcinoma (PDAC) tumor implantation and characterize phenotypes based on implantation site.Mice (n=8 per group) were implanted with 104 cells in the pancreas or flank. Hy15549 and Han4.13 cell lines were derived from primary murine PDAC (Ptf1-Cre; LSL-KRAS-G12D; Trp53 Lox/+) on C57BL/6 and FVB strains, respectively. Single-cell suspension and solid tumor implants were compared. Tumors were treated with two intravenous doses of FOLFIRINOX and responses evaluated.All mice developed pancreatic tumors within 7 days. Orthotopic tumors grew faster and larger than heterotopic tumors. By 3 weeks, orthotopic mice began losing weight, and showed declines in body condition requiring euthanasia starting at 4 weeks. Single-cell injection into the pancreas had near 100% engraftment, but solid tumor implant engraftment was ∼50% and was associated with growth restriction. Orthotopic tumors were significantly more responsive to intravenous FOLFIRINOX compared with heterotopic tumors, with greater reductions in size and increased apoptosis. Heterotopic tumors were more desmoplastic and hypovascular. However, drug uptake into tumor tissue was equivalent regardless of tumor location or degree of fibrosis, indicating that microenvironment differences between heterotopic and orthotopic tumors influenced response to therapy.Our results show that orthotopic and heterotopic allograft locations confer unique microenvironments that influence growth kinetics, desmoplastic response and angiogenesis. Tumor location influences chemosensitivity to FOLFIRINOX and should inform future preclinical trials.

Chemoradiotherapy screening in a novel biomimetic polymer based pancreatic cancer model

“…The 5 year survival rate is only 5-7% and it has barely improved over the last decades making it the 5 th leading cause of cancer related death in the UK (https://www.cancerresearchuk.org/health-professional/ cancer-statistics/statistics-by-cancer-type/pancreatic-cancer; accessed August 2019), 4 th in the USA 1 and the 7 th leading cause of cancer related death worldwide. [2][3][4][5] These disheartening statistics have been partly attributed to the disease's high resistance to current therapeutic regimes (radiotherapy & chemotherapy). PDAC's high resistance to treatment is linked to the tumour's complexity.…”

“…4,[20][21][22] Animal models (mostly murine) are more accurate/realistic than the 2D in vitro models in capturing a patient's situation and are currently the most widely used model for drug and radiotherapy testing at a pre-clinical level. 2,10,14,15,[23][24][25][26][27] However, they are expensive, difficult to reproduce and complex to use. 4,7,21,23,26,28 Additionally, there is evidence that animal models undergo signicant genetic changes that diverge from the evolutionary course observed in human disease, raising concerns about the models' translatability and application for personalised therapies.…”

“…4,7,21,23,26,28 Additionally, there is evidence that animal models undergo signicant genetic changes that diverge from the evolutionary course observed in human disease, raising concerns about the models' translatability and application for personalised therapies. 2 More recently, 3D in vitro models have emerged and are being developed as low cost, promising alternatives to animals. 7,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] However, most studies focus on the development of the actual 3D model and, to the best of our knowledge, there are very limited 3D studies on PDAC treatment screening (chemotherapy and radiotherapy) with most studies conducted in 3D spheroids (cell aggregates).…”

“…More specically, as described above, most treatment studies in spheroids have been monitored for a maximum of 7 days, 32,34,35,52 which is signicantly shorter in comparison to patients' treatment time-frame and to animal models which are usually assessed over a time frame of several weeks. 2,11,[14][15][16][17][55][56][57] Furthermore, in vitro models that allow long term post-treatment monitoring would enable the conduction of fractionated radiation screening wherein radiotherapeutic treatment is provided to the patients in serial smaller dosages over a specic time interval to minimise radiation related side effects. [58][59][60][61] We have recently developed a robust polyurethane (PU) scaffold for PDAC (re-)modelling, which overcomes some of the challenges faced in spheroid systems.…”

A novel transplantable model of lung cancer-associated tissue loss and disrupted muscle regeneration

“…This new and novel model for CAW addresses several needs in the field such as: (1) immunocompetence (i.e., a syngeneic model), (2) exhibits both heightened catabolism and suppressed regeneration, (3) exhibits both lean and fat mass loss, (4) exhibits an inflammatory microenvironment, (5) is flexible in timing and severity, and (6) arises in the tumor organ of origin. To the last point, recent studies have highlighted the importance of tumor location on both [27][28][29]. Our model is an easy and effective method to induce tumor formation in the lungs and concomitant CAW, using lung adenocarcinoma cells.…”