Publications by authors named "Marina Pajic"

80 Publications

TLR2 activation promotes tumour growth and associates with patient survival and chemotherapy response in pancreatic ductal adenocarcinoma.

Oncogene 2021 Oct 16;40(41):6007-6022. Epub 2021 Aug 16.

Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis, and is plagued by a paucity of targeted treatment options and tumour resistance to chemotherapeutics. The causal link between chronic inflammation and PDAC suggests that molecular regulators of the immune system promote disease pathogenesis and/or therapeutic resistance, yet their identity is unclear. Here, we couple endoscopic ultrasound-guided fine-needle aspiration, which captures tumour biopsies from all stages, with whole transcriptome profiling of PDAC patient primary tumours to reveal enrichment of the innate immune Toll-like receptor 2 (TLR2) molecular pathway. Augmented TLR2 expression associated with a 4-gene "TLR2 activation" signature, and was prognostic for survival and predictive for gemcitabine-based chemoresistance. Furthermore, antibody-mediated anti-TLR2 therapy suppressed the growth of human PDAC tumour xenografts, independent of a functional immune system. Our results support TLR2-based therapeutic targeting for precision medicine in PDAC, with further clinical utility that TLR2 activation is prognostic and predictive for chemoresponsiveness.
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http://dx.doi.org/10.1038/s41388-021-01992-2DOI Listing
October 2021

Cancer-Associated Fibroblasts in Pancreatic Ductal Adenocarcinoma Determine Response to SLC7A11 Inhibition.

Cancer Res 2021 07 12;81(13):3461-3479. Epub 2021 May 12.

The Garvan Institute of Medical Research and the Kinghorn Cancer Centre, Sydney, New South Wales, Australia.

Cancer-associated fibroblasts (CAF) are major contributors to pancreatic ductal adenocarcinoma (PDAC) progression through protumor signaling and the generation of fibrosis, the latter of which creates a physical barrier to drugs. CAF inhibition is thus an ideal component of any therapeutic approach for PDAC. SLC7A11 is a cystine transporter that has been identified as a potential therapeutic target in PDAC cells. However, no prior study has evaluated the role of SLC7A11 in PDAC tumor stroma and its prognostic significance. Here we show that high expression of SLC7A11 in human PDAC tumor stroma, but not tumor cells, is independently prognostic of poorer overall survival. Orthogonal approaches showed that PDAC-derived CAFs are highly dependent on SLC7A11 for cystine uptake and glutathione synthesis and that SLC7A11 inhibition significantly decreases CAF proliferation, reduces their resistance to oxidative stress, and inhibits their ability to remodel collagen and support PDAC cell growth. Importantly, specific ablation of SLC7A11 from the tumor compartment of transgenic mouse PDAC tumors did not affect tumor growth, suggesting the stroma can substantially influence PDAC tumor response to SLC7A11 inhibition. In a mouse orthotopic PDAC model utilizing human PDAC cells and CAFs, stable knockdown of SLC7A11 was required in both cell types to reduce tumor growth, metastatic spread, and intratumoral fibrosis, demonstrating the importance of targeting SLC7A11 in both compartments. Finally, treatment with a nanoparticle gene-silencing drug against SLC7A11, developed by our laboratory, reduced PDAC tumor growth, incidence of metastases, CAF activation, and fibrosis in orthotopic PDAC tumors. Overall, these findings identify an important role of SLC7A11 in PDAC-derived CAFs in supporting tumor growth. SIGNIFICANCE: This study demonstrates that SLC7A11 in PDAC stromal cells is important for the tumor-promoting activity of CAFs and validates a clinically translatable nanomedicine for therapeutic SLC7A11 inhibition in PDAC.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-2496DOI Listing
July 2021

Substrate-biased activity-based probes identify proteases that cleave receptor CDCP1.

Nat Chem Biol 2021 07 15;17(7):776-783. Epub 2021 Apr 15.

Mater Research Institute, The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.

CUB domain-containing protein 1 (CDCP1) is an oncogenic orphan transmembrane receptor and a promising target for the detection and treatment of cancer. Extracellular proteolysis of CDCP1 by poorly defined mechanisms induces pro-metastatic signaling. We describe a new approach for the rapid identification of proteases responsible for key proteolytic events using a substrate-biased activity-based probe (sbABP) that incorporates a substrate cleavage motif grafted onto a peptidyl diphenyl phosphonate warhead for specific target protease capture, isolation and identification. Using a CDCP1-biased probe, we identify urokinase (uPA) as the master regulator of CDCP1 proteolysis, which acts both by directly cleaving CDCP1 and by activating CDCP1-cleaving plasmin. We show that coexpression of uPA and CDCP1 is strongly predictive of poor disease outcome across multiple cancers and demonstrate that uPA-mediated CDCP1 proteolysis promotes metastasis in disease-relevant preclinical in vivo models. These results highlight CDCP1 cleavage as a potential target to disrupt cancer and establish sbABP technology as a new approach to identify disease-relevant proteases.
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http://dx.doi.org/10.1038/s41589-021-00783-wDOI Listing
July 2021

Breaking the cycle: Targeting of NDRG1 to inhibit bi-directional oncogenic cross-talk between pancreatic cancer and stroma.

FASEB J 2021 02;35(2):e21347

Cancer Metastasis and Tumour Microenvironment Program, Department of Pathology, University of Sydney, Sydney, NSW, Australia.

Pancreatic cancer (PaCa) is characterized by dense stroma that hinders treatment efficacy, with pancreatic stellate cells (PSCs) being a major contributor to this stromal barrier and PaCa progression. Activated PSCs release hepatocyte growth factor (HGF) and insulin-like growth factor (IGF-1) that induce PaCa proliferation, metastasis and resistance to chemotherapy. We demonstrate for the first time that the metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1), is a potent inhibitor of the PaCa-PSC cross-talk, leading to inhibition of HGF and IGF-1 signaling. NDRG1 also potently reduced the key driver of PaCa metastasis, namely GLI1, leading to reduced PSC-mediated cell migration. The novel clinically trialed anticancer agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), which upregulates NDRG1, potently de-sensitized PaCa cells to ligands secreted by activated PSCs. DpC and NDRG1 also inhibited the PaCa-mediated activation of PSCs via inhibition of sonic hedgehog (SHH) signaling. In vivo, DpC markedly reduced PaCa tumor growth and metastasis more avidly than the standard chemotherapy for this disease, gemcitabine. Uniquely, DpC was selectively cytotoxic against PaCa cells, while "re-programming" PSCs to an inactive state, decreasing collagen deposition and desmoplasia. Thus, targeting NDRG1 can effectively break the oncogenic cycle of PaCa-PSC bi-directional cross-talk to overcome PaCa desmoplasia and improve therapeutic outcomes.
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http://dx.doi.org/10.1096/fj.202002279RDOI Listing
February 2021

Fats and Mets, KRAS-Driven Lipid Dysregulation Affects Metastatic Potential in Pancreatic Cancer.

Cancer Res 2020 11;80(22):4886-4887

The Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia.

In this issue of , Rozeveld and colleagues present intriguing evidence of the importance of lipid droplets and hormone-sensitive lipase (HSL) in regulating the aggressive nature of pancreatic cancer. Initially demonstrating a dependency of preloaded lipids on an invasive phenotype, the authors then establish that oncogenic KRAS mutation downregulates HSL, thereby facilitating lipid storage during steady state. Thereafter, a phenotypic switch to oxidative metabolism with lipid utilization to fuel invasion and metastasis occurs. Experimentally, blocking the KRAS-HSL axis results in fewer lipid droplets, as well as metabolic reprogramming of the invasive cell phenotype, effectively reducing invasive capacity of KRAS-mutant pancreatic cancer. Of note, HSL overexpression in tumor cells also inhibited invasion, due to depletion of lipid droplets and the stored lipids, which are essential during invasion. Collectively, these novel findings highlight the importance of energy metabolism and its dynamic regulation in the evolution of the metastatic capacity of pancreatic cancer..
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http://dx.doi.org/10.1158/0008-5472.CAN-20-3082DOI Listing
November 2020

Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer.

Gastroenterology 2021 01 9;160(1):362-377.e13. Epub 2020 Oct 9.

Barts Cancer Institute, Queen Mary University of London, London, United Kingdom.

Background & Aims: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC.

Methods: We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids.

Results: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency.

Conclusions: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.
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http://dx.doi.org/10.1053/j.gastro.2020.09.043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8167930PMC
January 2021

Precision Oncology in Surgery: Patient Selection for Operable Pancreatic Cancer.

Ann Surg 2020 08;272(2):366-376

Department of Surgery, Universitätsklinikum Erlangen, Erlangen, Germany.

Objective: We aimed to define preoperative clinical and molecular characteristics that would allow better patient selection for operative resection.

Background: Although we use molecular selection methods for systemic targeted therapies, these principles are not applied to surgical oncology. Improving patient selection is of vital importance for the operative treatment of pancreatic cancer (pancreatic ductal adenocarcinoma). Although surgery is the only chance of long-term survival, 80% still succumb to the disease and approximately 30% die within 1 year, often sooner than those that have unresected local disease.

Method: In 3 independent pancreatic ductal adenocarcinoma cohorts (total participants = 1184) the relationship between aberrant expression of prometastatic proteins S100A2 and S100A4 and survival was assessed. A preoperative nomogram based on clinical variables available before surgery and expression of these proteins was constructed and compared to traditional measures, and a postoperative nomogram.

Results: High expression of either S100A2 or S100A4 was independent poor prognostic factors in a training cohort of 518 participants. These results were validated in 2 independent patient cohorts (Glasgow, n = 198; Germany, n = 468). Aberrant biomarker expression stratified the cohorts into 3 distinct prognostic groups. A preoperative nomogram incorporating S100A2 and S100A4 expression predicted survival and nomograms derived using postoperative clinicopathological variables.

Conclusions: Of those patients with a poor preoperative nomogram score, approximately 50% of patients died within a year of resection. Nomograms have the potential to improve selection for surgery and neoadjuvant therapy, avoiding surgery in aggressive disease, and justifying more extensive resections in biologically favorable disease.
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http://dx.doi.org/10.1097/SLA.0000000000003143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7373491PMC
August 2020

MTOR signaling orchestrates stress-induced mutagenesis, facilitating adaptive evolution in cancer.

Science 2020 06;368(6495):1127-1131

The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.

In microorganisms, evolutionarily conserved mechanisms facilitate adaptation to harsh conditions through stress-induced mutagenesis (SIM). Analogous processes may underpin progression and therapeutic failure in human cancer. We describe SIM in multiple in vitro and in vivo models of human cancers under nongenotoxic drug selection, paradoxically enhancing adaptation at a competing intrinsic fitness cost. A genome-wide approach identified the mechanistic target of rapamycin (MTOR) as a stress-sensing rheostat mediating SIM across multiple cancer types and conditions. These observations are consistent with a two-phase model for drug resistance, in which an initially rapid expansion of genetic diversity is counterbalanced by an intrinsic fitness penalty, subsequently normalizing to complete adaptation under the new conditions. This model suggests synthetic lethal strategies to minimize resistance to anticancer therapy.
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http://dx.doi.org/10.1126/science.aau8768DOI Listing
June 2020

HNF4A and GATA6 Loss Reveals Therapeutically Actionable Subtypes in Pancreatic Cancer.

Cell Rep 2020 05;31(6):107625

The Kinghorn Cancer Centre, 370 Victoria Street, Darlinghurst and Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.

Pancreatic ductal adenocarcinoma (PDAC) can be divided into transcriptomic subtypes with two broad lineages referred to as classical (pancreatic) and squamous. We find that these two subtypes are driven by distinct metabolic phenotypes. Loss of genes that drive endodermal lineage specification, HNF4A and GATA6, switch metabolic profiles from classical (pancreatic) to predominantly squamous, with glycogen synthase kinase 3 beta (GSK3β) a key regulator of glycolysis. Pharmacological inhibition of GSK3β results in selective sensitivity in the squamous subtype; however, a subset of these squamous patient-derived cell lines (PDCLs) acquires rapid drug tolerance. Using chromatin accessibility maps, we demonstrate that the squamous subtype can be further classified using chromatin accessibility to predict responsiveness and tolerance to GSK3β inhibitors. Our findings demonstrate that distinct patterns of chromatin accessibility can be used to identify patient subgroups that are indistinguishable by gene expression profiles, highlighting the utility of chromatin-based biomarkers for patient selection in the treatment of PDAC.
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http://dx.doi.org/10.1016/j.celrep.2020.107625DOI Listing
May 2020

PGRMC1 phosphorylation affects cell shape, motility, glycolysis, mitochondrial form and function, and tumor growth.

BMC Mol Cell Biol 2020 Apr 3;21(1):24. Epub 2020 Apr 3.

Graham Centre for Agricultural Innovation, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW, 2678, Australia.

Background: Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms.

Results: We demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/AKT activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/AKT activation. Mutation of Y180F strongly attenuated subcutaneous xenograft tumor growth in NOD-SCID gamma mice. Elsewhere we demonstrate altered metabolism, mutation incidence, and epigenetic status in these cells.

Conclusions: Altogether, these results indicate that mutational manipulation of PGRMC1 phosphorylation status exerts broad pleiotropic effects relevant to cancer and other cell biology.
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http://dx.doi.org/10.1186/s12860-020-00256-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7119165PMC
April 2020

Effective targeting of intact and proteolysed CDCP1 for imaging and treatment of pancreatic ductal adenocarcinoma.

Theranostics 2020 4;10(9):4116-4133. Epub 2020 Mar 4.

Mater Research Institute - The University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia.

: CUB domain-containing protein 1 (CDCP1) is a cell surface receptor regulating key signalling pathways in malignant cells. CDCP1 has been proposed as a molecular target to abrogate oncogenic signalling pathways and specifically deliver anti-cancer agents to tumors. However, the development of CDCP1-targeting agents has been questioned by its frequent proteolytic processing which was thought to result in shedding of the CDCP1 extracellular domain limiting its targetability. In this study, we investigated the relevance of targeting CDCP1 in the context of pancreatic ductal adenocarcinoma (PDAC) and assess the impact of CDCP1 proteolysis on the effectiveness of CDCP1 targeting agents. : The involvement of CDCP1 in PDAC progression was assessed by association analysis in several PDAC cohorts and the proteolytic processing of CDCP1 was evaluated in PDAC cell lines and patient-derived cells. The consequences of CDCP1 proteolysis on its targetability in PDAC cells was assessed using immunoprecipitation, immunostaining and biochemical assays. The involvement of CDCP1 in PDAC progression was examined by loss-of-function and experiments employing PDAC cells expressing intact or cleaved CDCP1. Finally, we generated antibody-based imaging and therapeutic agents targeting CDCP1 to demonstrate the feasibility of targeting this receptor for detection and treatment of PDAC tumors. : High CDCP1 expression in PDAC is significantly associated with poorer patient survival. In PDAC cells proteolysis of CDCP1 does not always result in the shedding of CDCP1-extracellular domain which can interact with membrane-bound CDCP1 allowing signal transduction between the different CDCP1-fragments. Targeting CDCP1 impairs PDAC cell functions and PDAC tumor growth independently of CDCP1 cleavage status. A CDCP1-targeting antibody is highly effective at delivering imaging radionuclides and cytotoxins to PDAC cells allowing specific detection of tumors by PET/CT imaging and superior anti-tumor effects compared to gemcitabine in models. : Independent of its cleavage status, CDCP1 exerts oncogenic functions in PDAC and has significant potential to be targeted for improved radiological staging and treatment of this cancer. Its elevated expression by most PDAC tumors and lack of expression by normal pancreas and other major organs, suggest that targeting CDCP1 could benefit a significant proportion of PDAC patients. These data support the further development of CDCP1-targeting agents as personalizable tools for effective imaging and treatment of PDAC.
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http://dx.doi.org/10.7150/thno.43589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086361PMC
May 2021

Rho-ROCK Signaling in Normal Physiology and as a Key Player in Shaping the Tumor Microenvironment.

Adv Exp Med Biol 2020 ;1223:99-127

Personalised Cancer Therapeutics Lab, The Kinghorn Cancer Centre, Sydney, NSW, Australia.

The Rho-ROCK signaling network has a range of specialized functions of key biological importance, including control of essential developmental processes such as morphogenesis and physiological processes including homeostasis, immunity, and wound healing. Deregulation of Rho-ROCK signaling actively contributes to multiple pathological conditions, and plays a major role in cancer development and progression. This dynamic network is critical in modulating the intricate communication between tumor cells, surrounding diverse stromal cells and the matrix, shaping the ever-changing microenvironment of aggressive tumors. In this chapter, we overview the complex regulation of the Rho-ROCK signaling axis, its role in health and disease, and analyze progress made with key approaches targeting the Rho-ROCK pathway for therapeutic benefit. Finally, we conclude by outlining likely future trends and key questions in the field of Rho-ROCK research, in particular surrounding Rho-ROCK signaling within the tumor microenvironment.
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http://dx.doi.org/10.1007/978-3-030-35582-1_6DOI Listing
February 2020

Systematic functional identification of cancer multi-drug resistance genes.

Genome Biol 2020 02 7;21(1):27. Epub 2020 Feb 7.

The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.

Background: Drug resistance is a major obstacle in cancer therapy. To elucidate the genetic factors that regulate sensitivity to anti-cancer drugs, we performed CRISPR-Cas9 knockout screens for resistance to a spectrum of drugs.

Results: In addition to known drug targets and resistance mechanisms, this study revealed novel insights into drug mechanisms of action, including cellular transporters, drug target effectors, and genes involved in target-relevant pathways. Importantly, we identified ten multi-drug resistance genes, including an uncharacterized gene C1orf115, which we named Required for Drug-induced Death 1 (RDD1). Loss of RDD1 resulted in resistance to five anti-cancer drugs. Finally, targeting RDD1 leads to chemotherapy resistance in mice and low RDD1 expression is associated with poor prognosis in multiple cancers.

Conclusions: Together, we provide a functional landscape of resistance mechanisms to a broad range of chemotherapeutic drugs and highlight RDD1 as a new factor controlling multi-drug resistance. This information can guide personalized therapies or instruct rational drug combinations to minimize acquisition of resistance.
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http://dx.doi.org/10.1186/s13059-020-1940-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006212PMC
February 2020

MCL-1 antagonism enhances the anti-invasive effects of dasatinib in pancreatic adenocarcinoma.

Oncogene 2020 02 18;39(8):1821-1829. Epub 2019 Nov 18.

Cancer Research Division, Garvan Institute of Medical Research and the Kinghorn Cancer Centre, 384 Victoria Street, Darlinghurst, NSW, 2010, Australia.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies. It is phenotypically heterogeneous with a highly unstable genome and provides few common therapeutic targets. We found that MCL1, Cofilin1 (CFL1) and SRC mRNA were highly expressed by a wide range of these cancers, suggesting that a strategy of dual MCL-1 and SRC inhibition might be efficacious for many patients. Immunohistochemistry revealed that MCL-1 protein was present at high levels in 94.7% of patients in a cohort of PDACs from Australian Pancreatic Genome Initiative (APGI). High MCL1 and Cofilin1 mRNA expression was also strongly predictive of poor outcome in the TCGA dataset and in the APGI cohort. In culture, MCL-1 antagonism reduced the level of the cytoskeletal remodeling protein Cofilin1 and phosphorylated SRC on the active Y416 residue, suggestive of reduced invasive capacity. The MCL-1 antagonist S63845 synergized with the SRC kinase inhibitor dasatinib to reduce cell viability and invasiveness through 3D-organotypic matrices. In preclinical murine models, this combination reduced primary tumor growth and liver metastasis of pancreatic cancer xenografts. These data suggest that MCL-1 antagonism, while reducing cell viability, may have an additional benefit in increasing the antimetastatic efficacy of dasatinib for the treatment of PDAC.
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http://dx.doi.org/10.1038/s41388-019-1091-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033042PMC
February 2020

RET gene rearrangements occur in a subset of pancreatic acinar cell carcinomas.

Mod Pathol 2020 04 26;33(4):657-664. Epub 2019 Sep 26.

Cancer Diagnosis and Pathology Group, Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW, Australia.

Pancreatic acinar cell carcinoma is relatively rare (1 to 2% of pancreatic malignancies) but may be under-recognized. In contrast to pancreatic ductal adenocarcinoma, most acinar cell carcinomas lack mutations in KRAS, DPC, CDKN2A or TP53, but appear to have a high incidence of gene rearrangements, with up to 20% reported to be driven by BRAF fusions. With the development of a new class of RET-specific tyrosine kinase inhibitors, which appear to have particularly strong activity against RET gene rearranged tumours, there is now considerable interest in identifying RET gene rearrangements across a wide range of cancers. RET rearrangements have been reported to occur at a very low incidence (<1%) in all pancreatic carcinomas. We postulated that given its unique molecular profile, RET gene rearrangements may be common in acinar cell carcinomas. We performed fluorescent in-situ hybridization (FISH) studies on a cohort of 40 acinar cell spectrum tumours comprising 36 pure acinar cell carcinomas, three pancreatoblastomas and one mixed acinar-pancreatic neuroendocrine tumour. RET gene rearrangements were identified in 3 (7.5%) cases and BRAF gene rearrangements in 5 (12.5%). All gene rearranged tumours were pure acinar cell carcinomas. Our findings indicate that amongst all pancreatic carcinomas, acinar carcinomas are highly enriched for potentially actionable gene rearrangements in RET or BRAF. FISH testing is inexpensive and readily available in the routine clinical setting and may have a role in the assessment of all acinar cell carcinomas-at this stage to recruit patients for clinical trials of new targeted therapies, but perhaps in the near future as part of routine care.
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http://dx.doi.org/10.1038/s41379-019-0373-yDOI Listing
April 2020

CAF hierarchy driven by pancreatic cancer cell p53-status creates a pro-metastatic and chemoresistant environment via perlecan.

Nat Commun 2019 08 12;10(1):3637. Epub 2019 Aug 12.

Cancer Research UK Beatson Institute, Glasgow Scotland, G61 BD, UK.

Heterogeneous subtypes of cancer-associated fibroblasts (CAFs) coexist within pancreatic cancer tissues and can both promote and restrain disease progression. Here, we interrogate how cancer cells harboring distinct alterations in p53 manipulate CAFs. We reveal the existence of a p53-driven hierarchy, where cancer cells with a gain-of-function (GOF) mutant p53 educate a dominant population of CAFs that establish a pro-metastatic environment for GOF and null p53 cancer cells alike. We also demonstrate that CAFs educated by null p53 cancer cells may be reprogrammed by either GOF mutant p53 cells or their CAFs. We identify perlecan as a key component of this pro-metastatic environment. Using intravital imaging, we observe that these dominant CAFs delay cancer cell response to chemotherapy. Lastly, we reveal that depleting perlecan in the stroma combined with chemotherapy prolongs mouse survival, supporting it as a potential target for anti-stromal therapies in pancreatic cancer.
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http://dx.doi.org/10.1038/s41467-019-10968-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691013PMC
August 2019

Targeting the complexity of Src signalling in the tumour microenvironment of pancreatic cancer: from mechanism to therapy.

FEBS J 2019 09 5;286(18):3510-3539. Epub 2019 Aug 5.

The Kinghorn Cancer Centre, The Garvan Institute of Medical Research, Sydney, Australia.

Pancreatic cancer, a disease with extremely poor prognosis, has been notoriously resistant to virtually all forms of treatment. The dynamic crosstalk that occurs between tumour cells and the surrounding stroma, frequently mediated by intricate Src/FAK signalling, is increasingly recognised as a key player in pancreatic tumourigenesis, disease progression and therapeutic resistance. These important cues are fundamental for defining the invasive potential of pancreatic tumours, and several components of the Src and downstream effector signalling have been proposed as potent anticancer therapeutic targets. Consequently, numerous agents that block this complex network are being extensively investigated as potential antiinvasive and antimetastatic therapeutic agents for this disease. In this review, we will discuss the latest evidence of Src signalling in PDAC progression, fibrotic response and resistance to therapy. We will examine future opportunities for the development and implementation of more effective combination regimens, targeting key components of the oncogenic Src signalling axis, and in the context of a precision medicine-guided approach.
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http://dx.doi.org/10.1111/febs.15011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771888PMC
September 2019

PAK inhibition by PF-3758309 enhanced the sensitivity of multiple chemotherapeutic reagents in patient-derived pancreatic cancer cell lines.

Am J Transl Res 2019 15;11(6):3353-3364. Epub 2019 Jun 15.

Department of Surgery, University of Melbourne, Austin Health Studley Road, Heidelberg, Victoria 3084, Australia.

Background/objective: Pancreatic ductal adenocarcinoma (PDA) remains the most lethal malignancy due to lack of an effective treatment. P21-activated kinases (PAKs) play a key role not only in cell proliferation and migration, but also in mediating chemo-resistance in PDA. The aim of this study was to investigate the combined effect of a PAK inhibitor PF-3758309 with multiple chemotherapeutic reagents on a panel of patient-derived PDA cell lines, and potential mechanisms involved.

Methods: Cells were treated with PF-3758309 plus or minus gemcitabine, 5-fluorouracil (5-FU) or abraxane, and cell growth was determined using a cell proliferation assay kit. Protein expression profiles were measured by Western blot. PDA cells were subcutaneously injected into the flanks of SCID mice which were then treated with saline, gemcitabine, PF-3758309, gemcitabine plus PF-3758309 or abraxane. Tumour growth was measured by volume and weight.

Results: PAK1 was correlated with CK19 expression, and PAK4 with α-SMA and palladin expression. Combination of PF-3758309 with 5-FU, gemcitabine or abraxane further suppressed cell growth of patient-derived PDA cell lines . The combination of PF-3758309 with gemcitabine maximally inhibited tumour growth by suppressing cell proliferation. PF-3758309 inhibited the expression of HIF-1α, palladin and α-SMA both and .

Conclusions: PAK inhibitor PF-3758309 can enhance anti-tumour effects of multiple chemotherapeutic reagents on a panel of patient-derived PDA cell lines. Combination of PF-3758309 with gemcitabine achieves comparable efficacy to combination of gemcitabine with abraxane, and thus provides a potential targeted therapy in the management of PDA.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614655PMC
June 2019

The Evolving Understanding of the Molecular and Therapeutic Landscape of Pancreatic Ductal Adenocarcinoma.

Diseases 2018 Nov 13;6(4). Epub 2018 Nov 13.

The Kinghorn Cancer Centre, The Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, Sydney, NSW 2010, Australia.

Pancreatic cancer is the third leading cause of cancer-related deaths, characterised by poor survival, marked molecular heterogeneity and high intrinsic and acquired chemoresistance. Only 10⁻20% of pancreatic cancer patients present with surgically resectable disease and even then, 80% die within 5 years. Our increasing understanding of the genomic heterogeneity of cancer suggests that the failure of definitive clinical trials to demonstrate efficacy in the majority of cases is likely due to the low proportion of responsive molecular subtypes. As a consequence, novel treatment strategies to approach this disease are urgently needed. Significant developments in the field of precision oncology have led to increasing molecular stratification of cancers into subtypes, where individual cancers are selected for optimal therapy depending on their molecular or genomic fingerprint. This review provides an overview of the current status of clinically used and emerging treatment strategies, and discusses the advances in and the potential for the implementation of precision medicine in this highly lethal malignancy, for which there are currently no curative systemic therapies.
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http://dx.doi.org/10.3390/diseases6040103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6313363PMC
November 2018

ATRX loss is an independent predictor of poor survival in pancreatic neuroendocrine tumors.

Hum Pathol 2018 12 3;82:249-257. Epub 2018 Aug 3.

Cancer Diagnosis and Pathology Group, Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia; University of Sydney, Sydney, NSW 2006, Australia; NSW Health Pathology, Department of Anatomical Pathology, Royal North Shore Hospital, St Leonards, NSW 2065, Australia. Electronic address:

Pancreatic neuroendocrine tumors (PanNETs) are rare neoplasms accounting for 1% to 2% of all pancreatic tumors. The biological behavior of PanNETs is heterogeneous and unpredictable, adding to the difficulties of clinical management. The DAXX (death domain associated protein) and ATRX (α-thalassemia/mental retardation syndrome X-linked) genes encode proteins involved in SWI/SNF-like chromatin remodeling. Somatic inactivating mutations in DAXX and ATRX are frequent in PanNETs, mutually exclusive, and associated with telomere dysfunction, resulting in genomic instability and alternate lengthening of telomeres. We sought to assess the clinical significance of the loss of the ATRX and DAXX proteins as determined by immunohistochemistry (IHC) in patients with PanNET. From an unselected cohort of 105 patients, we found ATRX loss in 10 tumors (9.5%) and DAXX loss in 16 (15.2%). DAXX and ATRX losses were confirmed mutually exclusive and associated with other adverse clinicopathological variables and poor survival in univariate analysis. In addition, ATRX loss was also associated with higher AJCC stage and infiltrative tumor borders. However, only ATRX loss, lymphovascular invasion, and perineural spread were independent predictors of poor overall survival in multivariate analysis. In conclusion, loss of expression of ATRX as determined by IHC is a useful independent predictor of poor overall survival in PanNETs. Given its relative availability, ATRX loss as determined by IHC may have a role in routine clinical practice to refine prognostication in patients with PanNET.
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http://dx.doi.org/10.1016/j.humpath.2018.07.032DOI Listing
December 2018

Changes in cell morphology guide identification of tubulin as the off-target for protein kinase inhibitors.

Pharmacol Res 2018 08 23;134:166-178. Epub 2018 Jun 23.

The University of Sydney, Faculty of Medicine and Health, Charles Perkins Centre, NSW 2006, Australia. Electronic address:

In the field of kinase inhibitors for applications in cancer research, tubulin is emerging as a targeted cellular protein that can significantly contribute to their activities. However, investigation of kinase inhibitors beyond the kinome is an area often neglected. Herein, we describe the results of pharmacological studies using drugs targeting kinases, tubulin or both. A key finding is that if cells are treated with a kinase inhibitor unintentionally targeting tubulin, their characteristic shape will diminish within a short timeframe. These changes in cell morphology are not seen when cells are treated with bona fide kinase inhibitors that do not directly target tubulin. Thus, early changes in cell morphology upon treatments are a strong indication that the inhibitor is directly targeting tubulin. Recognizing tubulin as a target of kinase inhibitors will build confidence in the future mechanistic studies using kinase inhibitors.
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http://dx.doi.org/10.1016/j.phrs.2018.06.023DOI Listing
August 2018

Intravital Imaging to Monitor Therapeutic Response in Moving Hypoxic Regions Resistant to PI3K Pathway Targeting in Pancreatic Cancer.

Cell Rep 2018 06;23(11):3312-3326

Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia. Electronic address:

Application of advanced intravital imaging facilitates dynamic monitoring of pathway activity upon therapeutic inhibition. Here, we assess resistance to therapeutic inhibition of the PI3K pathway within the hypoxic microenvironment of pancreatic ductal adenocarcinoma (PDAC) and identify a phenomenon whereby pronounced hypoxia-induced resistance is observed for three clinically relevant inhibitors. To address this clinical problem, we have mapped tumor hypoxia by both immunofluorescence and phosphorescence lifetime imaging of oxygen-sensitive nanoparticles and demonstrate that these hypoxic regions move transiently around the tumor. To overlay this microenvironmental information with drug response, we applied a FRET biosensor for Akt activity, which is a key effector of the PI3K pathway. Performing dual intravital imaging of drug response in different tumor compartments, we demonstrate an improved drug response to a combination therapy using the dual mTORC1/2 inhibitor AZD2014 with the hypoxia-activated pro-drug TH-302.
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http://dx.doi.org/10.1016/j.celrep.2018.05.038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019737PMC
June 2018

Rho Kinase Inhibition by AT13148 Blocks Pancreatic Ductal Adenocarcinoma Invasion and Tumor Growth.

Cancer Res 2018 06 18;78(12):3321-3336. Epub 2018 Apr 18.

Cancer Research UK Beatson Institute, Glasgow, United Kingdom.

The high mortality of pancreatic cancer demands that new therapeutic avenues be developed. The orally available small-molecule inhibitor AT13148 potently inhibits ROCK1 and ROCK2 kinases that regulate the actomyosin cytoskeleton. We previously reported that ROCK kinase expression increases with human and mouse pancreatic cancer progression and that conditional ROCK activation accelerates mortality in a genetically modified ; (KPC) mouse pancreatic cancer model. In this study, we show that treatment of KPC mouse and human TKCC5 patient-derived pancreatic tumor cells with AT13148, as well as the ROCK-selective inhibitors Y27632 and H1152, act comparably in blocking ROCK substrate phosphorylation. AT13148, Y27632, and H1152 induced morphologic changes and reduced cellular contractile force generation, motility on pliable discontinuous substrates, and three-dimensional collagen matrix invasion. AT13148 treatment reduced subcutaneous tumor growth and blocked invasion of healthy pancreatic tissue by KPC tumor cells without affecting proliferation, suggesting a role for local tissue invasion as a contributor to primary tumor growth. These results suggest that AT13148 has antitumor properties that may be beneficial in combination therapies or in the adjuvant setting to reduce pancreatic cancer cell invasion and slow primary tumor growth. AT13148 might also have the additional benefit of enabling tumor resection by maintaining separation between tumor and healthy tissue boundaries. Preclinical evaluation of a small-molecule ROCK inhibitor reveals significant effects on PDAC invasion and tumor growth, further validating ROCK kinases as viable therapeutic targets in pancreatic cancer. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-1339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005347PMC
June 2018

BRAF gene rearrangements can be identified by FISH studies in pancreatic acinar cell carcinoma.

Pathology 2018 04 3;50(3):345-348. Epub 2018 Mar 3.

Cancer Diagnosis and Pathology Group, Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW, Australia; University of Sydney, Sydney, NSW, Australia; NSW Health Pathology, Department of Anatomical Pathology, Royal North Shore Hospital, St Leonards, NSW, Australia. Electronic address:

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http://dx.doi.org/10.1016/j.pathol.2017.09.027DOI Listing
April 2018

∆133p53 isoform promotes tumour invasion and metastasis via interleukin-6 activation of JAK-STAT and RhoA-ROCK signalling.

Nat Commun 2018 01 17;9(1):254. Epub 2018 Jan 17.

Children's Medical Research Institute, University of Sydney, Sydney, NSW, 2145, Australia.

∆122p53 mice (a model of ∆133p53 isoform) are tumour-prone, have extensive inflammation and elevated serum IL-6. To investigate the role of IL-6 we crossed ∆122p53 mice with IL-6 null mice. Here we show that loss of IL-6 reduced JAK-STAT signalling, tumour incidence and metastasis. We also show that ∆122p53 activates RhoA-ROCK signalling leading to tumour cell invasion, which is IL-6-dependent and can be reduced by inhibition of JAK-STAT and RhoA-ROCK pathways. Similarly, we show that Δ133p53 activates these pathways, resulting in invasive and migratory phenotypes in colorectal cancer cells. Gene expression analysis of colorectal tumours showed enrichment of GPCR signalling associated with ∆133TP53 mRNA. Patients with elevated ∆133TP53 mRNA levels had a shorter disease-free survival. Our results suggest that ∆133p53 promotes tumour invasion by activation of the JAK-STAT and RhoA-ROCK pathways, and that patients whose tumours have high ∆133TP53 may benefit from therapies targeting these pathways.
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http://dx.doi.org/10.1038/s41467-017-02408-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772473PMC
January 2018

Reshaping the Tumor Stroma for Treatment of Pancreatic Cancer.

Gastroenterology 2018 03 26;154(4):820-838. Epub 2017 Dec 26.

The Garvan Institute of Medical Research, Sydney, New South Wales, Australia; The Kinghorn Cancer Center, Sydney, New South Wales, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia. Electronic address:

Pancreatic cancer is accompanied by a fibrotic reaction that alters interactions between tumor cells and the stroma to promote tumor progression. Consequently, strategies to target the tumor stroma might be used to treat patients with pancreatic cancer. We review recently developed approaches for reshaping the pancreatic tumor stroma and discuss how these might improve patient outcomes. We also describe relationships between the pancreatic tumor extracellular matrix, the vasculature, the immune system, and metabolism, and discuss the implications for the development of stromal compartment-specific therapies.
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http://dx.doi.org/10.1053/j.gastro.2017.11.280DOI Listing
March 2018

Three-dimensional organotypic matrices from alternative collagen sources as pre-clinical models for cell biology.

Sci Rep 2017 12 4;7(1):16887. Epub 2017 Dec 4.

Garvan Institute of Medical Research & The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia.

Organotypic co-cultures bridge the gap between standard two-dimensional culture and mouse models. Such assays increase the fidelity of pre-clinical studies, to better inform lead compound development and address the increasing attrition rates of lead compounds within the pharmaceutical industry, which are often a result of screening in less faithful two-dimensional models. Using large-scale acid-extraction techniques, we demonstrate a step-by-step process to isolate collagen I from commercially available animal byproducts. Using the well-established rat tail tendon collagen as a benchmark, we apply our novel kangaroo tail tendon collagen as an alternative collagen source for our screening-ready three-dimensional organotypic co-culture platform. Both collagen sources showed equal applicability for invasive, proliferative or survival assessment of well-established cancer models and clinically relevant patient-derived cancer cell lines. Additional readouts were also demonstrated when comparing these alternative collagen sources for stromal contributions to stiffness, organization and ultrastructure via atomic force microscopy, second harmonic generation imaging and scanning electron microscopy, among other vital biological readouts, where only minor differences were found between the preparations. Organotypic co-cultures represent an easy, affordable and scalable model to investigate drug responses within a physiologically relevant 3D platform.
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http://dx.doi.org/10.1038/s41598-017-17177-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5715059PMC
December 2017

miR-139-5p Modulates Radiotherapy Resistance in Breast Cancer by Repressing Multiple Gene Networks of DNA Repair and ROS Defense.

Cancer Res 2018 01 27;78(2):501-515. Epub 2017 Nov 27.

St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.

Radiotherapy is essential to the treatment of most solid tumors and acquired or innate resistance to this therapeutic modality is a major clinical problem. Here we show that miR-139-5p is a potent modulator of radiotherapy response in breast cancer via its regulation of genes involved in multiple DNA repair and reactive oxygen species defense pathways. Treatment of breast cancer cells with a miR-139-5p mimic strongly synergized with radiation both and , resulting in significantly increased oxidative stress, accumulation of unrepaired DNA damage, and induction of apoptosis. Several miR-139-5p target genes were also strongly predictive of outcome in radiotherapy-treated patients across multiple independent breast cancer cohorts. These prognostically relevant miR-139-5p target genes were used as companion biomarkers to identify radioresistant breast cancer xenografts highly amenable to sensitization by cotreatment with a miR-139-5p mimetic. The microRNA described in this study offers a potentially useful predictive biomarker of radiosensitivity in solid tumors and a generally applicable druggable target for tumor radiosensitization. .
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http://dx.doi.org/10.1158/0008-5472.CAN-16-3105DOI Listing
January 2018

Transient targeting of the pancreatic cancer stroma as a 'fine-tuned' anti-tumor and anti-metastatic therapy.

Oncotarget 2017 Oct 3;8(49):84635-84636. Epub 2017 Oct 3.

Paul Timpson and Marina Pajic: The Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW & The Kinghorn Cancer Centre, Cancer Division, Australia and St Vincent's Clinical School, Faculty of Medicine, University of NSW, Australia.

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http://dx.doi.org/10.18632/oncotarget.21468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5689559PMC
October 2017
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