Mechanical factors in the tumor microenvironment play an important role in response to a variety of cellular activities in cancer cells. Here, we utilized polyacrylamide hydrogels with varying ...physical parameters simulating tumor and metastatic target tissues to investigate the effect of substrate stiffness on the growth, phenotype, and chemotherapeutic response of ovarian cancer cells (OCCs). We found that increasing the substrate stiffness promoted the proliferation of SKOV-3 cells, an OCC cell line. This proliferation coincided with the nuclear translocation of the oncogene Yes-associated protein. Additionally, we found that substrate softening promoted elements of epithelial-mesenchymal transition (EMT), including mesenchymal cell shape changes, increase in vimentin expression, and decrease in E-cadherin and β-catenin expression. Growing evidence demonstrates that apart from contributing to cancer initiation and progression, EMT can promote chemotherapy resistance in ovarian cancer cells. Furthermore, we evaluated tumor response to standard chemotherapeutic drugs (cisplatin and paclitaxel) and found antiproliferation effects to be directly proportional to the stiffness of the substrate. Nanomechanical studies based on atomic force microscopy (AFM) have revealed that chemosensitivity and chemoresistance are related to cellular mechanical properties. The results of cellular elastic modulus measurements determined by AFM demonstrated that Young’s modulus of SKOV-3 cells grown on soft substrates was less than that of cells grown on stiff substrates. Gene expression analysis of SKOV-3 cells showed that mRNA expression can be greatly affected by substrate stiffness. Finally, immunocytochemistry analyses revealed an increase in multidrug resistance proteins, namely, ATP binding cassette subfamily B member 1 and member 4 (ABCB1 and ABCB4), in the cells grown on the soft gel resulting in resistance to chemotherapeutic drugs. In conclusion, our study may help in identification of effective targets for cancer therapy and improve our understanding of the mechanisms of cancer progression and chemoresistance.
The mechanobiological response mechanism of the fenestrae of liver sinusoidal endothelial cells (LSECs) to the physical stiffness of the extracellular matrix (ECM) remains unclear. We investigated ...how the mechanical properties of their substrates affect the LSECs' fenestrae by the nitric oxide (NO)-dependent pathway and how they relate to the progression of hepatic sinus capillarization during liver fibrosis. We detected different stiffnesses of ECM in the progress of liver fibrosis (LF) and developed polyacrylamide hydrogel (PAM) substrates to simulate them. Softer stiffness substrates contributed to LSECs maintaining fenestrae phenotype in vitro. The stiffness of liver fibrosis tissue could be reversed in vivo via treatment with anti-ECM deposition drugs. Similarly, the capillarization of LSECs could be reversed by decreasing the ECM stiffness. Our results also indicate that the NO-dependent pathway plays a key regulatory role in the capillarization of ECM-LSECs. Our study reveals ECM-induced mechanotransduction of capillarized LSECs through a NO-dependent pathway via a previously unrevealed mechanotransduction mechanism. The elucidation of this mechanism may offer precise biomechanics-specific intervention strategies targeting liver fibrosis progression.
Nowadays, nanoparticles (NPs) are considered to be ideal tools for bioimaging and drug delivery. Although increasing research has focused on NP biodistribution, transportation in the interstitial ...architecture has been neglected. The entire body is connected by the interstitial architecture, which can provide a long-range and direct pathway for NP biodistribution in a nonvascular system. In this study, we report that 10-nm gold NPs injected directly into the interstitial architecture of the tarsal tunnel of rats (intervaginal space injection (ISI)) were delivered to the brain without crossing the blood-brain barrier. Furthermore, NaGdF
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nanoparticles were used to explore the transportation route by magnetic resonance imaging. The results demonstrated that, after ISI, the NaGdF
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nanoparticles were transported through the perivascular interstitial space of the carotid arteries and brain vessels to the brain. This is a special nonvascular transportation route like a stream based on the interstitial architecture that provides an alternative pathway for NP biodistribution.
The mechanical properties of cellular microenvironments play important roles in regulating cellular functions. Studies of the molecular response of endothelial cells to alterations in substrate ...stiffness could shed new light on the development of cardiovascular disease. Quantitative real-time PCR is a current technique that is widely used in gene expression assessment, and its accuracy is highly dependent upon the selection of appropriate reference genes for gene expression normalization. This study aimed to evaluate and identify optimal reference genes for use in studies of the response of endothelial cells to alterations in substrate stiffness.
Four algorithms, GeNorm(PLUS), NormFinder, BestKeeper, and the Comparative ΔCt method, were employed to evaluate the expression of nine candidate genes. We observed that the stability of potential reference genes varied significantly in human umbilical vein endothelial cells on substrates with different stiffness. B2M, HPRT-1, and YWHAZ are suitable for normalization in this experimental setting. Meanwhile, we normalized the expression of YAP and CTGF using various reference genes and demonstrated that the relative quantification varied according to the reference genes.
Consequently, our data show for the first time that B2M, HPRT-1, and YWHAZ are a set of stably expressed reference genes for accurate gene expression normalization in studies exploring the effect of subendothelial matrix stiffening on endothelial cell function. We furthermore caution against the use of GAPDH and ACTB for gene expression normalization in this experimental setting because of the low expression stability in this study.
Gold nanoparticles and carbon nanotubes have attracted substantial attention in recent years for their potential applications in photothermal therapy (PTT) as an emerging breakthrough in cancer ...treatment. Herein, a hybrid nanomaterial of gold nanostars/multiwalled carbon nanotubes (MWCNTs) was synthesized by two-step reduction via the control of several synthetic conditions such as the reducing agent, pH value, concentration and ratio of reagents. The material shows good biocompatibility and high photothermal conversion efficiency, demonstrating its applicability in PTT. The lack of surfactant in the synthesis process made the hybrid nanomaterial cell-friendly, with no effects on viability in vitro. The MWCNT/gold nanostars hybrid nanomaterial presented 12.4% higher photothermal efficiency than gold nanostars alone and showed a 2.4-fold increase over gold nanospheres based on a heating test under 808 nm laser irradiation. Moreover, the MWCNTs/gold nanostars at low concentration (0.32 nM) exhibited remarkably improved photothermal cancer cell-killing efficacy, which may be attributed to the surface plasmon resonance absorption of the gold nanostars and the combined effects of enhanced coupling between the MWCNTs and gold nanostars. Collectively, these results demonstrate that the MWCNTs/gold nanostars developed herein show prominent photothermal value, and thus may serve as a novel photothermal agent for cancer therapy.
Soft matter has attracted extensive attention due to its special physical/chemical properties and holds great promise in many applications. However, obtaining a detailed understanding of both complex ...fluid and mass transport in soft matter, especially in hierarchical porous media of biological tissues, still remains a huge challenge. Herein, inspired by fast tracer transport in loose connective tissues of living systems, we observed an interesting phenomenon of fast molecular transport in situ in an artificial hierarchical multiphase porous medium （a micrometer scale hydrophobic fiber network filled with nanometer scale hydrophilic porous medium）, which was simply fabricated through electro- spinning technology and polymerization. The transportation speed of molecules in the micrometer fiber network is larger than simple diffusion in nanometer media, which is better described by Fick＇s law. We further proved that the phenomenon is based on the nanoconfined air/water/solid interface around the micrometer hydrophobic fibers. We focus on the key factors, referring to SA, （the confined multiphase area around the microfibers） and Nc （the connectivity node degree of the skeletal portion in the nanometer hydrogel medium）. Next, a quantitative parameter, VTCM （transport chance mean-value）, was introduced to describe the molecular transport capability of the fiber network within hierarchical multiphase porous systems. These fundamental advances can be applied de novo to understand the process of so-called simple diffusion in biological systems, and even to re-describe many molecular events in biologically nanoconfined spaces.
Nanomechanical behaviors of single living cardiomyocytes are quantitatively observed using calculated torsions and deflections of an AFM cantilever. The lateral contractions are related to the ...calcium intensity within rather than the vertical beating power of the cardiomyocytes. Drug-induced nanomechanical changes of cardiomyocytes were further investigated by measuring lateral contractions in real time.
We address the modelling of tip-cell membrane interactions under high speed atomic force microscopy. Using a home-made device with a scanning area of 100 × 100 μm(2), in situ imaging of living cells ...is successfully performed under loading rates from 1 to 50 Hz, intending to enable detailed descriptions of physiological processes in living samples.
Cell mechanics is an emerging field of research for translational medicine. Here, the cell is modeled as poroelastic cytoplasm wrapped by tensile membrane (poroelastic@membrane model) and is ...characterized by the atomic force microscopy (AFM). The parameters of cytoskeleton network modulus EC, cytoplasmic apparent viscosity ηC, and cytoplasmic diffusion coefficient DC are used to describe the mechanical behavior of cytoplasm, and membrane tension γ is used to evaluate the cell membrane. Poroelastic@membrane analysis of breast cells and urothelial cells show that non‐cancer cells and cancer cells have different distribution regions and distribution trends in the four‐dimensional space composed of EC, ηC. From non‐cancer to cancer cells, there is often a trend of γ, EC, ηC decreases and DC increases. Patients with urothelial carcinoma at different malignant stages can be distinguished at high sensitivity and specificity by analyzing the urothelial cells from tissue or urine. However, sampling directly from tumor tissues is an invasive method, may lead to undesirable consequences. Thus, AFM‐based poroelastic@membrane analysis of urothelial cells from urine may provide a non‐invasive and no‐bio‐label method to detecting urothelial carcinoma.
This paper presents a method to characterize the mechanical properties of cells based on poroelastic@membrane model. The method can intuitively show the mechanical differences between non‐cancer cells and cancer cells and is expected to be applied to the diagnosis of urothelial carcinoma with a non‐invasive method in clinic.
Renal fibrosis is the final pathological change of kidney disease, it has also been recognized to be critical for the final progression of diabetic nephropathy (DN) to kidney failure. Acteoside (ACT) ...is a phenylethanoid glycoside widely distributed in dicotyledonous plants. It has many pharmacological activities, such as anti-oxidation, anti-inflammation, anti-cancer, neuroprotection, cardiovascular protection, anti-diabetes, bone and cartilage protection, liver and kidney protection, and antibacterial activity. This study aims to investigate the protective effects of ACT on renal interstitial fibrosis in rats with DN induced by intraperitoneal injection of streptozocin (STZ) combined with unilateral nephrectomy and its mechanism. In vivo and in vitro, the effects of ACT on reactive oxygen species (ROS) level, oxidative tubular injury, as well as damage of autophagic flux and lysosome in the DN model were detected. Results indicate that administration of ACT delayed the progression of renal interstitial fibrosis in DN by anti-oxidation and regulating the autophagy-lysosome pathway, which may potentially be attributed to the regulatory influence of ACT on transcription factor EB (TFEB).
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