Interstitial Fluid Pressure Research Articles

Minimum design requirements for a poroelastic mimic of articular cartilage

The exceptional functional performance of articular cartilage (load-bearing and lubrication) is attributed to its poroelastic structure and resulting interstitial fluid pressure. Despite this, there remains no engineered cartilage repair material capable of achieving physiologically relevant poroelasticity. In this work we develop in silico models to guide the design approach for poroelastic mimics of articular cartilage. We implement the constitutive models in FEBio, a PDE solver for multiphasic mechanics problems in biological and soft materials. We investigate the influence of strain rate, boundary conditions at the contact interface, and fiber modulus on the reaction force and load sharing between the solid and fluid phases. The results agree with the existing literature that when fibers are incorporated the fraction of load supported by fluid pressure is greatly amplified and increases with the fiber modulus. This result demonstrates that a stiff fibrous phase is a primary design requirement for poroelastic mimics of articular cartilage. The poroelastic model is fit to experimental stress-relaxation data from bovine and porcine cartilage to determine if sufficient design constraints have been identified. In addition, we fit experimental data from FiHy™, an engineered material which is claimed to be poroelastic. The fiber-reinforced poroelastic model was able to capture the primary physics of these materials and demonstrates that FiHy™ is beginning to approach a cartilage-like poroelastic response. We also develop a fiber-reinforced poroelastic model with a bonded interface (rigid contact) to fit stress relaxation data from an osteochondral explant and FiHy™ + bone substitute. The model fit quality is similar for both the chondral and osteochondral configurations and clearly captures the first order physics. Based on this, we propose that physiological poroelastic mimics of articular cartilage should be developed under a fiber-reinforced poroelastic framework.

Recent advances in bacteria-mediated cancer therapy.

Cancer is among the leading cause of deaths worldwide. Although conventional therapies have been applied in the fight against the cancer, the poor oxygen, low extracellular pH, and high interstitial fluid pressure of the tumor microenvironment mean that these treatments fail to completely eradicate cancer cells. Recently, bacteria have increasingly been considered to be a promising platform for cancer therapy thanks to their many unique properties, such as specific tumor-targeting ability, high motility, immunogenicity, and their use as gene or drug carriers. Several types of bacteria have already been used for solid and metastatic tumor therapies, with promising results. With the development of synthetic biology, engineered bacteria have been endowed with the controllable expression of therapeutic proteins. Meanwhile, nanomaterials have been widely used to modify bacteria for targeted drug delivery, photothermal therapy, magnetothermal therapy, and photodynamic therapy, while promoting the antitumor efficiency of synergistic cancer therapies. This review will provide a brief introduction to the foundation of bacterial biotherapy. We begin by summarizing the recent advances in the use of many different types of bacteria in multiple targeted tumor therapies. We will then discuss the future prospects of bacteria-mediated cancer therapies.

Experimental study of contacting surfaces microgeometry and gas gap impact on thermal contact conductance of metallic joints

Thermal contact resistance is an important phenomenon in heat transfer and impacts many fields of technology. The interrelated influences of many factors—such as geometry and microgeometry of contacting surfaces, their mechanical and thermal properties, apparent contact pressure, type and properties of interstitial fluid—make prediction of this resistance problematic and necessitate both theoretical and experimental research. The paper reports an experimental study of thermal contact conductance (the reciprocal of thermal contact resistance) of joints created by flat, conforming metallic surfaces in static contact. The measurements were performed for samples made of mild steel and stainless steel with relatively low roughness (σ = 0.5 - 2.14 µm) and large slope of asperities (m = 0.4 – 1.3), resulting in values of σef/mef = 1.25 - 1.96 µm that are distinctly lower than reported in the majority of experimental research on thermal contact conductance. The apparent contact pressure was changed from 1.5 to 11 MPa and for some cases up to 19 MPa. Analysis of the results obtained showed that the correlations available in the literature, for greater values of roughness and smaller asperity slope, mostly overestimated the predicted thermal contact conductance. The elasticity indices values for samples used in this study indicated plastic deformation of asperities, but it was concluded that the smoothest surfaces of both kinds of steel underwent elastic deformation. A new experimental correlation for contact of mild steel surfaces (σ = 0.5 - 2.14 µm, σef/mef = 1.25 - 1.96) was proposed. The results of this study indicate the need for further investigation of thermal contact conductance, especially for this range of surface microgeometry parameters, which is not dealt with in the correlations available in the literature. There is also a need to study the impact of asperity curvature on contact conductance. The results of this study proved the important role that air gaps play in the transfer of heat across a joint. The gap conductance values were predicted correctly for low mechanical loads and rough surfaces.

MoS2 nanoflower-mediated enhanced intratumoral penetration and piezoelectric catalytic therapy

The absence of lymphatic vessels in tumors leads to the retention of interstitial fluid, and the formation of an inverse pressure difference between the tumor and blood vessels hinders drug delivery deep into the tumor, which leads to tumor recurrence and metastasis. Therefore, we designed a novel strategy to downregulate tumor interstitial fluid pressure (TIFP) by water splitting in the tumor interstitium based on piezoelectric catalysis nanomedicine. First, the chemotherapeutic drug doxorubicin (DOX) was loaded on the piezoelectric catalytic material MoS2 and then encapsulated with tumor cell membrane (CM) to obtain MD@C. MD@C could not only target the tumor through homologous targeting but, more importantly, also triggered piezoelectric catalytic water splitting under ultrasound (US) stimulation; as a result, the TIFPs of U14 and PAN02 tumor-bearing mice were reduced to 57.14% and 45.5%, respectively, and the tumor inhibition rates of MD@C were 96.75% and 99.21%, which increased the perfusion of blood-derived drugs in the tumors. Moreover, the hydroxyl radicals generated by piezoelectric catalysis could effectively inhibit the growth of tumors in combination with DOX. Consequently, the piezoelectric catalytic water splitting strategy of MD@C can enhance drug delivery, providing a new universal platform for the treatment of solid malignant tumors.

Pneumatic piston hydrostatic bioreactor for cartilage tissue engineering

During exercise, mechanical loads from the body are transduced into interstitial fluid pressure changes which are sensed as dynamic hydrostatic forces by cells in cartilage. The effects of these loading forces in health and disease are of interest to biologists, but the availability of affordable equipment for in vitro experimentation is an obstacle to research progress. Here, we report the development of a cost-effective hydropneumatic bioreactor system for research in mechanobiology. The bioreactor was assembled from readily available components (a closed-loop stepped motor and pneumatic actuator) and a minimal number of easily-machined crankshaft parts, whilst the cell culture chambers were custom designed by the biologists using CAD and entirely 3 D printed in PLA. The bioreactor system was shown to be capable of providing cyclic pulsed pressure waves at a user-defined amplitude and frequency ranging from 0 to 400 kPa and up to 3.5 Hz, which are physiologically relevant for cartilage. Tissue engineered cartilage was created from primary human chondrocytes and cultured in the bioreactor for five days with three hours/day cyclic pressure (300 kPa at 1 Hz), simulating moderate physical exercise. Bioreactor-stimulated chondrocytes significantly increased their metabolic activity (by 21%) and glycosaminoglycan synthesis (by 24%), demonstrating effective cellular transduction of mechanosensing. Our Open Design approach focused on using ‘off-the-shelf’ pneumatic hardware and connectors, open source software and in-house 3 D printing of bespoke cell culture containers to resolve long-standing problems in the availability of affordable bioreactors for laboratory research.

Hydraulic fracturing analysis in fluid-saturated porous medium.

This paper addresses fluid-driven crack propagation in a porous medium. Cohesive interface elements are employed to model the behaviour of the crack. To simulate hydraulic fracturing, a fluid pressure degree of freedom is introduced inside the crack, separate from the fluid degrees of freedom in the bulk. Powell-Sabin B-splines, which are based on triangles, are employed to describe the geometry of the domain and to interpolate the field variables: displacements and interstitial fluid pressure. Due to their -continuity, the stress and pressure gradient are smooth throughout the whole domain, enabling a direct assessment of the fracture criterion at the crack tip and ensuring local mass conservation. Due to the use of triangles, crack insertion and remeshing are straightforward and can be done directly in the physical domain. During remeshing a mapping of the state vector (displacement and interstitial fluid pressure) is required. For this, a new methodology is exploited based on a least-square fit with the energy balance and mass conservation as constraints. The accuracy to model free crack propagation is demonstrated by two numerical examples, including crack propagation in a plate with twonotches.

Editorial: Emerging roles and mechanisms of stromal cells in carcinomas at the molecular level

For an extended period, the tumor microenvironment (TME) has not been focused on in the field of 20 cancer biology before Stephen Paget's "seed and soil" hypothesis [1]. The representative characters of 21 cells involved in TME are high plasticity and continuous phenotypic and functional change. For 22 example, the desmoplastic reaction in pancreatic cancer is a critical histological observation, tightly 23 associated with significantly increasing the interstitial fluid pressure within the tumor niche.

The ambivalent nature of the relationship between lymphatics and cancer

Do lymphatic vessels support cancer cells? Or are they vessels that help suppress cancer development? It is known that the lymphatic system is a vehicle for tumor metastasis and that the lymphangiogenic regulator VEGF-C supports the tumor. One such role of VEGF-C is the suppression of the immune response to cancer. The lymphatic system has also been correlated with an increase in interstitial fluid pressure of the tumor microenvironment. On the other hand, lymphatic vessels facilitate immune surveillance to mount an immune response against tumors with the support of VEGF-C. Furthermore, the activation of lymphatic fluid drainage may prove to filter and decrease tumor interstitial fluid pressure. In this review, we provide an overview of the dynamic between lymphatics, cancer, and tumor fluid pressure to suggest that lymphatic vessels may be used as an antitumor therapy due to their capabilities of immune surveillance and fluid pressure drainage. The application of this potential may help to prevent tumor proliferation or increase the efficacy of drugs that target cancer.

Development of Injectable and Biodegradable Needle-Type Starch Implant for Effective Intratumoral Drug Delivery and Distribution.

IntroductionCompared to intravenous administration, intratumoral drug administration enables the direct delivery of drugs to tumors and mitigates the systemic absorption of drugs and associated drug-induced side effects. However, intratumoral drug administration presents several challenges. The high interstitial fluid pressure (IFP) of the tumor prevents the retention of drugs within the tumor; thus, significant amounts of the drugs are absorbed systemically through the bloodstream or delivered to non-target sites. To solve this problem, in this study, a drug-enclosed needle-type starch implant was developed that can overcome IFP and remain in the tumor.MethodsInjectable needle-type starch implants (NS implants) were prepared by starch gelatinization and drying. The structure, cytotoxicity, and anticancer effects of the NS implants were evaluated. Biodistribution of NS implants was evaluated in pork (in vitro), dissected liver (ex vivo), and 4T1 tumors in mice (in vivo) using a fluorescence imaging device.ResultsThe prepared NS implants exhibited a hydrogel structure after water absorption. NS implants showed effective cytotoxicity and anticancer effects by photothermal therapy (PTT). The NS implant itself has sufficient strength and can be easily injected into a desired area. In vivo, the NS implant continuously delivered drugs to the tumor more effectively and uniformly than conventional hydrogels and solutions.ConclusionThis study demonstrated the advantages of needle-type implants. An injectable NS implant can be a new formulation that can effectively deliver drugs and exhibit anticancer effects.

Abstract PO024: Combination therapy with PXS-5505 improves chemotherapeutic efficacy and reduces myeloid immune suppression in murine cholangiocarcinoma – a novel therapeutic strategy for clinical translation

Abstract Introduction: Despite growing prevalence, 5-year survival for cholangiocarcinoma remains poor due to an immunosuppressive fibroinflammatory stroma, featuring abundant collagen and cancer-associated fibroblasts. Lysyl oxidases (LOX) consist of 5 secreted enzymes that catalyze collagen cross-linking, resulting in increased tumor stroma density and facilitate immune evasion. Here, we present our findings of pan-LOX inhibition with a novel orally dosed agent (PXS-5505) in a murine model of CCA. Methods: Immunohistochemistry (IHC) analysis was performed on a human tissue macro-array of CCA. Mice that develop spontaneous CCA (KPPC) or orthotopically injected with a syngeneic cell line derived from a KPPC tumor were screened for disease onset and progression with ultrasonography (U/S). Groups of KPPC mice or mice bearing orthotopic tumors were enrolled into treatment cohorts of chemotherapy with or without PXS-5505 to evaluate survival and to perform fixed time point studies with treated tumors including assessment of intratumoral interstitial fluid pressure (IFP), IHC analysis of tumor markers, chemotherapy drug perfusion into tumors by mass spectrometry, and flow cytometry analysis of tumor single cell suspensions for stromal and immune cell populations. Results: IHC analysis demonstrated significantly elevated LOX expression in both human and KPPC CCA (p<0.0001 and p=0.0025, respectively) compared to normal liver controls. High LOX expression was associated with worse disease-free (p=0.02) and overall (p=0.03) survival in resected human CCA specimens. KPPC mice treated with the combination of chemotherapy plus PXS-5505 demonstrated delayed tumor growth (p<0.0001) and ascites onset (p=0.005) with improved survival (median 77 vs. 59 days, p=0.001) compared to chemotherapy alone. In addition, combination therapy reduced IFP (p=0.002) and was associated with increased mean blood vessel area (p<0.0001) and increased concentration of intratumoral chemotherapy levels (p=0.02) compared to chemotherapy alone. Subsequent IHC revealed increased cell death through cleaved caspase-3 (p=0.0003) and damage-associated molecular pattern (DAMP) release through HMGB1 (p=0.0004). Flow cytometry analysis of tumors treated with combination therapy demonstrated reduced prevalence of tumor-infiltrating monocytic and granulocytic myeloid-derived suppressor cell populations (p=0.002 and p=0.01, respectively) and tumor associated macrophages (TAMs; p=0.02). There were increased CD4+ (p=0.01) T-cells with a reduced proportion of Treg+CD4+ (p<0.0001) T-cells. The ratio of CD8:Treg was significantly elevated in the combination therapy cohort (p=0.001) and depletion of T-cells in orthotopic tumors abrogated the improved survival with combination therapy. Conclusions: LOX is elevated in human CCA and its expression correlates with prognosis following resection. Combination therapy with PXS-5505 delays tumor progression and improves survival in murine CCA models. Thus, chemotherapy combined with PXS-5505 represents a novel therapeutic strategy for treating CCA. Citation Format: Paul R Burchard, Luis I Ruffolo, Nicholas A Ullman, Yatee Dave, Benjamin Dale, Mary Georger, Rachel Jewell, Nabeel Badri, Brian A Belt, David C Linehan, Roberto Hernandez-Alejandro. Combination therapy with PXS-5505 improves chemotherapeutic efficacy and reduces myeloid immune suppression in murine cholangiocarcinoma – a novel therapeutic strategy for clinical translation [abstract]. In: Proceedings of the AACR Special Conference: Advances in the Pathogenesis and Molecular Therapies of Liver Cancer; 2022 May 5-8; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(17_Suppl):Abstract nr PO024.

Collagenase-Loaded H-TiO2 Nanoparticles Enhance Ultrasound Imaging-Guided Sonodynamic Therapy in a Pancreatic Carcinoma Xenograft Model via Digesting Stromal Barriers.

Sonodynamic therapy (SDT), a noninvasive therapy that relies on sonosensitizers and generates reactive oxygen species (ROS), has attracted considerable attention in the treatment of pancreatic cancer. However, being surrounded by dense stromal barriers, pancreatic cancer exhibits high interstitial fluid pressure (IFP) and hypoxia in the tumor microenvironment (TME), resulting in poor SDT efficacy. Collagenase-loaded hollow TiO2 (Col-H-TiO2) nanoparticles (NPs) capable of degrading stromal barriers and producing sufficient ROS production were synthesized in this study. After administration of NPs in the patient-derived xenograft (PDX) model, ultrasonic irradiation-released collagenase degraded tumor matrix fibers, decreased intratumoral IFP, and enhanced the penetration and retention of NPs within tumor tissues. Moreover, the NPs accumulated within the tumor not only generate abundant ROS under the influence of ultrasound irradiation but also improve intratumoral ultrasound signal, providing ultrasonic imaging-guided highly effective SDT for pancreatic cancer. In conclusion, this research improves the SDT technique and enhances the visualization of pancreatic cancer by remodeling the TME and is a promising strategy for further clinical applications.

A model of magnetic nanoparticle transport and their effects in tumor areas: Assessment of desirable magnetic properties

A mathematical model of the transport of drug loaded magnetic nanoparticles and their effects on tumor evolution is presented. The model is developed in the context of continuum mechanics and transport phenomena, with the main variables, such as interstitial fluid pressure and flow, nanoparticle, cell and oxygen concentrations, cell-phase velocities and pressures being described as continuous fields over the tumor and surrounding tissue. The evolution of tumor shape and size is obtained from the numerical solution of the model equations. Simulations are presented comparing the behavior in the absence of any drug, in the presence of drug loaded nanoparticles but without a magnetic field, and under the action of a magnetic field of varying intensity. It is observed that magnetic targeting can have a profound effect on the distribution of nanoparticles inside the tumor and a clearly apparent and quantitatively significant influence on its progression. With the aid of magnetic targeting, the otherwise almost inaccessible area, due to the effects of the interstitial fluid pressure and flow, can be exposed to significant and controlled nanoparticle concentrations. For this to be achieved, it suffices for the magnetically induced nanoparticle velocity to be a fraction of the interstitial fluid flow velocity, yet in the same order of magnitude. This assessment provides a guiding rule for the rational design of magnetic nanoparticles and the quest of suitable magnetic fields.

Tumor Biology; Usefulness of Thermosensitive and pH Sensitive Polymeric Nanoparticles for Tumor Targeting: A Review

Polymeric nanoparticles (PNPs) have attracted the interest of many scientists and have been utilized in an increasing number of fields during the last two decades. The conventional chemotherapeutic agents have poor pharmacokinetic parameters such as non-specific distribution of drugs, the lack of drug specific affinity towards a pathological site, and thus necessitating large dose of a drug to achieve high local concentration in the body leading to systemic toxicity associated with serious side effects. A thorough and precise understanding of tumor microenvironment such as angiogenesis, tumor pH, enhanced permeation and retention (EPR) effect, abnormal lymphatics, multidrug resistance (MDR) and high interstitial fluid pressure, allows designing drug delivery systems that specifically target anti-cancer drugs to tumors. An attempt has been made in this article to highlight the temperature and pH sensitive PNPs, and PNPs with dual and double response to both temperature and pH that have a distinct capacity to target tumors with limited effect on healthy tissues. The stimuli responsive nanoparticles are classified based on their mechanism of response to temperature and pH. Structure of the polymer, methods of drug loading, and characterization of PNPs are elucidated.
 Keywords: Polymeric nanoparticles; pH sensitive polymers; Thermosensitive polymers; Tumor microenvironment; Multidrug resistance; Drug loading.

A computational approach to determine key anatomic landmarks on pelvis and its application to acetabular orientation assessment and hip computational biomechanics.

The determination of anatomic landmarks on the pelvis is an important procedure in orthopaedics, computational biomechanics and morphometrics. This study aimed to develop a robust method for determining the anatomic landmarks on the pelvis and demonstrate the application of the method in assessing the native acetabular orientation and developing multiscale computational modelling for hip biomechanics. Two Matlab algorithms, named "Pelvisor" and "Acetabulor", were developed to determine four anatomic landmarks on the pelvis and assess the acetabular orientation in the natural hip. The algorithms were then applied to: (1) assess the native acetabular orientations for a cohort of subjects; (2) develop a multiscale computational modelling to investigate the biomechanical behaviour of the biphasic cartilage in the natural hip joint. Results showed that the present method can accurately determine the key anatomic landmarks on the pelvis and assess the acetabular orientation in the natural hip joint. Significant differences in acetabular inclination and anteversion between males and females were identified, with larger orientations in females. The interstitial fluid pressure in the cartilage supported over 90% of loading during gait, and the stresses and strains within the solid matrix of the cartilage were as low as 1.8 MPa and 0.12, respectively.

Regulation of Interstitial Fluid Pressure for Improved Intratumor Drug Permeability and Nanozyme-Enhanced Chemocatalytic Therapy

Regulation of Interstitial Fluid Pressure for Improved Intratumor Drug Permeability and Nanozyme-Enhanced Chemocatalytic Therapy

The Utilization of Bevacizumab in Patients with Advanced Ovarian Cancer: A Systematic Review of the Mechanisms and Effects.

Most ovarian cancer cases are diagnosed at an advanced stage (III or IV), in which a primary debulking surgery combined with adjuvant systemic chemotherapy is the standard management. Since targeted therapy is less toxic to human cells than systemic chemotherapy, it has drawn much attention and become more popular. Angiogenesis is a critical process during the proliferation of ovarian cancer cells. Currently, many studies have put emphases on anti-angiogenetic medication, such as bevacizumab, the first and most investigated angiogenesis inhibitor that can exert anti-neoplastic effects. Bevacizumab is a recombinant humanized monoclonal antibody that has been approved for first-line maintenance treatment of advanced ovarian cancer. This review is a summary of current literature about the molecular mechanisms of actions, safety, and effects of bevacizumab for use in advanced epithelial ovarian cancer. Some common side effects of bevacizumab will be also discussed. As an inhibitor of angiogenesis, bevacizumab binds to circulating vascular endothelial growth factor (VEGF) and thereby inhibits the binding of VEGF to its receptors on the surface of endothelial cells. Neutralization of VEGF prevents neovascularization and leads to apoptosis of tumor endothelial cells and a decrease in interstitial fluid pressure within the tumors, which allows greater capacity for chemotherapeutic drugs to reach specific targeted sites. Grossly, bevacizumab has demonstrated some significant therapeutic benefits in many randomized trials in combination with the standard chemotherapy for advanced epithelial ovarian cancer. Based on the available evidence, a higher dosage and a longer duration of bevacizumab appear to achieve better therapeutic effects and progression-free survival. On the other hand, patients with more severe diseases or at a higher risk of progression seem to benefit more from bevacizumab use. However, many unknown aspects of bevacizumab, including detailed mechanisms of actions, effectiveness, and safety for the treatment of ovarian cancer, warrant further investigation.

Abstract 1042: Fc3TSR improves intratumoral treatment delivery by normalizing tumor vasculature and reducing interstitial fluid pressure in an orthotopic, syngeneic mouse model of epithelial ovarian cancer

Abstract A hallmark of solid tumors is the need for vascularization to supply oxygen and nutrients. Aggressive pro-angiogenic signals induced by tumors lead to malformation of vessels characterized by reduced pericyte coverage and low perfusion. As a result of this vascular dysfunction, tumors have elevated hypoxia and high interstitial fluid pressure (IFP), yielding an aggressive phenotype, and reducing efficacy and trafficking of intravenous therapies to the tumor core. Anti-angiogenic therapies aim to reduce angiogenic stimuli and normalize tumor vessels. The three type-1-repeat (3TSR) region of thrombospondin-1 contains the majority of its anti-angiogenic properties in a small bioactive peptide. These functions are mediated through the membrane protein, CD36. We have previously shown that administration of native 3TSR leads to improved tumor perfusion, and enhancing delivery of chemotherapy drugs and oncolytic viruses. We have developed a novel compound, Fc3TSR, that has two 3TSR peptides linked with a Fc to increase in vitro and in vivo efficacy. In an orthotopic, mouse model of ovarian cancer, we examined the effect of Fc3TSR treatment on tumor IFP using a 1.2Fr pressure catheter guided into the tumor core of anesthetized mice. Compared to untreated controls, mice treated with Fc3TSR had significantly lower IFP, even after considering differences in heart rate among animals. Immunofluorescence on fixed sentinel lymph nodes revealed enhanced presence of immune cells, a positive predictor of lymphatic patency. To determine impact on chemotherapy delivery, mice were injected with 40mCi paclitaxel and tumor uptake of the isotope was measured. At 12, 24 and 48h post injection, Fc3TSR treated tumors had significantly increased uptake of paclitaxel compared to untreated or 3TSR treated mice. In vitro cell viability assays and western blot analysis of cleaved-caspase-3 revealed that Fc3TSR enhances direct apoptosis in human ovarian cell lines (OVCAR-2 and 36M2) compared to untreated cells or those treated with native 3TSR at equimolar concentrations. In a human subcutaneous xenograft model using 36M2 cells in SCID mice, Fc3TSR significantly reduced tumor volume as a single agent compared to PBS controls.Fc3TSR causes direct ovarian tumor cell apoptosis in vitro and significant anti-tumor effects in vivo. In vivo, Fc3TSR causes potent vascular normalization, decreases tumor hypoxia and IFP in the tumor core. As such, Fc3TSR has the potential to remodel multiple aspects of the tumor microenvironment which would otherwise obstruct treatment delivery and efficacy in solid tumors. The multi-modal aspects of Fc3TSR makes this therapeutic approach attractive for the treatment of advanced ovarian cancer and other malignancies that typically overcome single-agent therapy. Citation Format: Kathy Matuszewska, Madison Pereira, Leslie Ogilvie, Duncan Petrik, Allison Gartung, Dipak Panigrahy, Kin-Ming Lo, Jack Lawler, Jeremy Simpson, Jim Petrik. Fc3TSR improves intratumoral treatment delivery by normalizing tumor vasculature and reducing interstitial fluid pressure in an orthotopic, syngeneic mouse model of epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1042.

Abstract 5796: Targeting poorly differentiated and anaplastic thyroid cancer microenvironment via TNF-α/TGF-β/LOX signaling to improve drug delivery and treatment efficacy

Abstract A major limitation of current systemic solid cancer therapies is the failure to effectively deliver drugs to cancer cells. Solid tumors have high cell density and poor lymphatic drainage, leading to higher interstitial fluid pressure (IFP). We previously showed that the tumor microenvironment of poorly-differentiated (PDTC) and anaplastic thyroid cancer (ATC) can be selectively and effectively treated with nanomedicine carrying recombinant human Tumor Necrosis Factor α (TNFα)(CYT6091), resulting in vascular leakage, decreased IFP, and increased intratumoral concentration of paclitaxel in vivo. The purpose of this study is to investigate the mechanisms involved in a TNFα-induced reduction of IFP. We investigated the effects of TNF-α on cytokines and extracellular matrix (ECM) proteins in tumor microenvironment. Our data showed that TNFα treatment downregulated transforming growth factor-beta (TGF-β) and Lysyl oxidase (LOX) and upregulated several ECM proteins. However, we observed LOX upregulation when we treated thyroid cancer with siTNF-α-receptor 1 or 2 followed by TNF-α, suggesting the involvement of TNF-α-receptors in treatment resistance. In addition to the role of LOX in stiffening the ECM, causing a barrier to drug delivery, we showed overexpression of LOX in aggressive thyroid cancer. We observed increased vascular leakage in siLOX-treated thyroid cancer xenografts, mimicking the effect of CYT-6091. Furthermore, we confirmed that the LOX expression in thyroid cancer is positively associated with transforming growth factor receptor 1 (TGFBR1). In TCGA thyroid cancer database the mRNA expression of TGFBR1 was positively correlated with those of ECM regulatory genes (ITGB2, ITGA2 and COL1A1) which were downregulated with TNF-α treated thyroid cancer cells. To assess the role of TGF-β on vascular permeability, we found that the TGF-β inhibitor (SB-431542) induced in vitro vascular leakage, while the recombinant TGF-β reversed TNF-α-induced in vitro vascular leakage in HUVEC cells. SB-431542 and TGF-β neutralizing antibodies independently and markedly improved treatment efficacy of paclitaxel in in vitro thyroid cancer 3D tumor spheroids. Moreover, TGF-β1 inhibition downregulates the protein levels of Smad3 molecules in thyroid cancer cells. TCGA database studies of thyroid cancer patient samples showed that SMAD3 positively correlated with TGFBR1 and LOX, suggesting the involvement of SMAD3 in TGF-β/LOX signaling in the TME. Citation Format: DIPRANJAN LAHA. Targeting poorly differentiated and anaplastic thyroid cancer microenvironment via TNF-α/TGF-β/LOX signaling to improve drug delivery and treatment efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5796.

The Hippo pathway drives the cellular response to hydrostatic pressure

Cells need to rapidly and precisely react to multiple mechanical and chemical stimuli in order to ensure precise context‐dependent responses. This requires dynamic cellular signalling events that ensure homeostasis and plasticity when needed. A less well‐understood process is cellular response to elevated interstitial fluid pressure, where the cell senses and responds to changes in extracellular hydrostatic pressure. Here, using quantitative label‐free digital holographic imaging, combined with genome editing, biochemical assays and confocal imaging, we analyse the temporal cellular response to hydrostatic pressure. Upon elevated cyclic hydrostatic pressure, the cell responds by rapid, dramatic and reversible changes in cellular volume. We show that YAP and TAZ, the co‐transcriptional regulators of the Hippo signalling pathway, control cell volume and that cells without YAP and TAZ have lower plasma membrane tension. We present direct evidence that YAP/TAZ drive the cellular response to hydrostatic pressure, a process that is at least partly mediated via clathrin‐dependent endocytosis. Additionally, upon elevated oscillating hydrostatic pressure, YAP/TAZ are activated and induce TEAD‐mediated transcription and expression of cellular components involved in dynamic regulation of cell volume and extracellular matrix. This cellular response confers a feedback loop that allows the cell to robustly respond to changes in interstitial fluid pressure.

Abstract 3809: Adaptation of prostate cancer cell lines to tumor microenvironment culture conditions induces expression of androgen receptor splice variant 7 and contributes to drug resistance

Abstract The tumor microenvironment (TME) has several characteristics that distinguish it from normal tissue, including elevated interstitial fluid pressures and hypoxic environments. Both pressurized and hypoxic culture conditions can influence gene and protein expression of tumor cells which can result in tumor metastasis and drug resistance. Enzalutamide is effective in treating metastatic castration-resistant prostate cancer (mCRPC), but majority of patients eventually develop resistance to enzalutamide. One of the biomarkers of enzalutamide resistance is the expression of androgen receptor splice variant 7 (AR-V7), but the mechanism of how AR-V7 expression is upregulated in prostate cancer is unclear. To investigate the influence of TME culture conditions on prostate cancer cell lines, 22Rv1 and LNCaP cell lines were incubated under pressurized and hypoxic culture conditions (2 PSI + 1%O2) for a minimum of 7 days. We compared cell growth, morphology changes, gene expression profiles and drug response to enzalutamide treatment. The growth of 22Rv1 and LNCaP cells was markedly inhibited under TME culture conditions, accompanied by distinct changes in cell morphology. 22Rv1 and LNCaP cells cultured under TME conditions exhibited increased resistance to enzalutamide treatment. Higher levels of AR-V7 expression were detected in 22Rv1 and LNCaP cell lines maintained for 7 days in TME culture conditions. RNA-seq data identified 700+ genes that were differentially expressed in 22Rv1 and LNCaP cell lines adapted to TME culture conditions. GSEA analysis identified signaling pathways associated with hypoxia, glycolysis and epithelial-mesenchymal transition were upregulated under TME culture conditions, and the pathways of xenobiotic metabolism and oxidative phosphorylation were downregulated by TME culture conditions. In summary, adaptation to TME culture conditions can promote the expression of AR-V7 in prostate cancer cell lines and can contribute to enzalutamide drug resistance. Adaptation of cell lines to TME culture conditions can provide meaningful insights into mechanisms of drug resistance while providing a novel approach to identify targets and biomarkers of drug resistance. Citation Format: Yunmin Li, Albert Wong, Ann Lu, James Lim. Adaptation of prostate cancer cell lines to tumor microenvironment culture conditions induces expression of androgen receptor splice variant 7 and contributes to drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3809.