Metastatic phenotype and immunosuppressive tumour microenvironment in pancreatic ductal adenocarcinoma: Key role of the urokinase plasminogen activator (PLAU)

Abstract

BackgroundPrevious studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition.MethodsThis study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis.ResultsOur analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis.ConclusionElevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU.

Effects of anoxic prognostic model on immune microenvironment in pancreatic cancer

“…PLAU encodes a secretory serine protease that converts plasminogen to plasminase 31 . PLAU has also been found to be involved in a variety of cancers and is associated with poor prognosis in a variety of cancers 32 ; Some experimental studies have proved that PLAU overexpression is associated with poor prognosis of PAAD, and plays an important role in PAAD resistance, invasion and migration 33 . However, the role of PLAU in the anoxia process of pancreatic cancer has not been well understood, and our study aims to fill this gap.…”

Ion Transport and Inhibitor Binding by Human NHE1: Insights from Molecular Dynamics Simulations and Free Energy Calculations

“…12,13 In cancer cells, elevated NHE1 activity enhances malignant transformation, 14 invasion, and metastasis. 15,16 NHE1 has been implicated in cancer regulation, 17 progression, and metastasis of breast, 15,18−20 ovarian, 21,22 pancreatic, 23,24 gastric, 25 and prostate 26 cancers as well as hepatocellular carcinoma. 27 The existence of cation/H + exchangers was first proposed in 1961.…”

“…It controls the electroneutral exchange of a single intracellular H + for an extracellular Na + ion (1:1 stoichiometry) across the plasma membrane, acting to elevate intracellular pH (pH i ). NHE1 thus regulates Na + levels, pH i , cell volume, − proliferation, and cell migration , and has been correlated with pathological conditions such as heart disease − and hypertension. , In cancer cells, elevated NHE1 activity enhances malignant transformation, invasion, and metastasis. , NHE1 has been implicated in cancer regulation, progression, and metastasis of breast, ,− ovarian, , pancreatic, , gastric, and prostate cancers as well as hepatocellular carcinoma …”

Automated Patch Clamp Screening of Amiloride and 5-N,N-Hexamethyleneamiloride Analogs Identifies 6-Iodoamiloride as a Potent Acid-Sensing Ion Channel Inhibitor

“…33 The authors described pH-dependent inhibition of ASIC1 activity in Chinese Hamster Ovary (CHO) cells and demonstrated that the leads occupied an allosteric binding site within the extracellular PcTX1 domain through solution of a X-ray cocrystal complex with chicken ASIC1a (Protein Data Bank ID 6X9H). The aminoindazole lead 4-fluoro-6-((1-(5fluoro-2-methylpyridin-4-yl)azetidin-3-yl)oxy)-1H-indazol-3amine (13) showed potent activity against wild-type ASIC1 at pH 6.0 (WT IC 50 = 25 nM), with target engagement demonstrated by significant decreases in inhibition against heterologously expressed ASIC1 bearing single alanine substitutions at the putative binding site (F98A IC 50 = 746 We recently reported on the activity of two novel series of 6substituted amiloride 35 and 5-N,N-hexamethylene amiloride 28 analogs as inhibitors of urokinase plasminogen activator (uPA), a TLSP linked to cancer metastasis 36,37 rheumatoid arthritis, 38 and other inflammatory diseases. 39,40 Lead inhibitors from these efforts showed low nanomolar uPA potency, high target selectivity across the serine hydrolase superfamily, loss of unwanted ENaC activity, low hERG activity, and in vivo antimetastatic effects in xenografted mouse models of lung and pancreatic cancer.…”

“…We recently reported on the activity of two novel series of 6-substituted amiloride and 5- N , N -hexamethylene amiloride analogs as inhibitors of urokinase plasminogen activator (uPA), a TLSP linked to cancer metastasis , rheumatoid arthritis, and other inflammatory diseases. , Lead inhibitors from these efforts showed low nanomolar uPA potency, high target selectivity across the serine hydrolase superfamily, loss of unwanted ENaC activity, low hERG activity, and in vivo antimetastatic effects in xenografted mouse models of lung and pancreatic cancer. ,, In this study, we characterize the structure–activity relationships of compounds from these series and related amiloride derivatives as inhibitors of proton-activated currents mediated by ASICs using automated patch clamp electrophysiology, identify an analog with improved potency, and test its potential as pharmacological tool to probe endogenous human and rodent ASIC function.…”