Nano-mechanical reinforcement in drug-resistant ovarian cancer cells

The effects of cetuximab and cisplatin anti-cancer drugs on the mechanical properties of the lung cancerous cells using atomic force microscope

Each anti-cancer drug has special effects on the target cells. One of the most important reasons to recommend an anti-cancer drug is related to the influences of it on the mechanical properties of the target cells. In this study, the effects of cetuximab and cisplatin anti-cancer drugs on the mechanical properties of A-549 and Calu-6 cells as the cancerous lung cells have been investigated. For both of the cells and anti-cancer drugs, MTT assessment has been used to define the convenient dosages for 24 and 48 h incubations based on IC50 concentration for the cell line viability. The mechanical specifications of the cells before and after treatment were obtained using nanoindentation by the JPK Instruments' NanoWizard3 atomic force microscope. The results show that cetuximab increases the stiffness of A-549 cell from 1225 to 3403 and 12 690 Pa for 24 and 48 h incubations. The influence of cetuximab on the Calu-6 shows that the elastic modulus after 24 and 48 h culture times increases about cisplatin anti-cancer drug, for A-549 cell indicates that the elastic modulus rises from 1225 to 1506 and 2375 Pa for 24 and 48 h, respectively. For Calu-6 cell, cisplatin has an important role to increase the stiffness of the cell. Applying cisplatin increases the elastic modulus from 33 to 682.8 Pa for 24 h and 1105 Pa after 48 h incubations.

A nanomechanical strategy involving focal adhesion kinase for overcoming drug resistance in breast cancer

Despite implementation of nanomechanical studies in cancer research, studies on the nanomechanical aspects of drug resistance in cancer are lacking. Here, we established the mechanical signatures of drug-resistant breast cancer cells using atomic force microscopy-based indentation techniques and functionalized nanopatterned substrates (NPS). Additionally, we examined the expression of proteins pertinent to focal adhesions in order to elucidate the molecular signatures responsible for the acquisition of drug resistance in breast cancer cells. Drug-resistant breast cancer cells exhibited mechanical reinforcement, increased actin stress fibers, dysfunctional mechano-reciprocal interaction with the NPS, vinculin overexpression, and improved focal adhesion kinase (FAK) activity. Owing to differences in FAK activation upon co-treatment with a FAK inhibitor, the drug-resistant breast cancer cells were eradicated more efficiently than invasive breast cancer cells having pro-survival activity. These findings demonstrated the potential of a novel co-treatment regimen using FAK inhibitors for overcoming drug resistance in breast cancer cells.

Atomic Force Microscopy for Tumor Research at Cell and Molecule Levels

Tumors have posed a serious threat to human life and health. Researchers can determine whether or not cells are cancerous, whether the cancer cells are invasive or metastatic, and what the effects of drugs are on cancer cells by the physical properties such as hardness, adhesion, and Young's modulus. The atomic force microscope (AFM) has emerged as a key important tool for biomechanics research on tumor cells due to its ability to image and collect force spectroscopy information of biological samples with nano-level spatial resolution and under near-physiological conditions. This article reviews the existing results of the study of cancer cells with AFM. The main foci are the operating principle of AFM and research advances in mechanical property measurement, ultra-microtopography, and molecular recognition of tumor cells, which allows us to outline what we do know it in a systematic way and to summarize and to discuss future directions.

A naphthalimide-based peptide conjugate for concurrent imaging and apoptosis induction in cancer cells by utilizing endogenous hydrogen sulfide

The excessive production of endogenous hydrogen sulfide (H2S) in cancer cells leads to enhanced tumor growth and metastasis. On the other hand, decreased endogenous H2S suppresses tumor growth. The reported approaches for inhibiting tumor growth are selective silencing of the tumor-promoting genes and pharmacological inhibition of these proteins. To enhance the antitumor efficacy of frontline chemotherapeutic agents, herein, we synthesized a highly sensitive endogenous H2S responsive fluorescent probe, i.e., a hydrogen sulfide-sensing naphthalimide-based peptide conjugate (HSNPc), which showed selective inhibition of proliferation of cancer cells due to apoptosis induction. Furthermore, HSNPc suppressed the glycolytic reserve, a critical energy source for the proliferation of cancer cells. HSNPc also decreased the Young's modulus of HeLa cells compared to the control cells, which demonstrated a direct relation between cell apoptosis and cell stiffness. Taken together, we demonstrated the dual function of detection and killing of cancer cells by HSNPc that can be likened to a theranostic role.

Substrate Stiffness Modulates the Growth, Phenotype, and Chemoresistance of Ovarian Cancer Cells

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.

Integrin α5 mediates intrinsic cisplatin resistance in three-dimensional nasopharyngeal carcinoma spheroids via the inhibition of phosphorylated ERK /caspase-3 induced apoptosis

Nasopharyngeal carcinoma (NPC) originates in the nasopharynx epithelium. Although concurrent chemoradiation therapy followed by chemotherapy is considered as an effective treatment, there is substantial drug resistance in locally advanced NPC patients. One major contributor to the chemoresistance includes aberrant expression of cell adhesion molecules, such as integrin α and β subunits, giving rise to cell adhesion-mediated drug resistance. Thus, the aim of this study was to investigate the effect of integrin α5 on the development of intrinsic cisplatin resistance in NPC and the associated underlying mechanisms using in vitro three-dimensional (3D) spheroid models, as well as induced cisplatin-resistant NPC (NPCcisR). We demonstrated that established 3D highly- (5-8F) and lowly- (6-10B) metastatic NPC spheroids overexpressed integrin α5 and aggravated their resistance to cisplatin. Besides, enhanced integrin α5 resulted in substantially reduced growth, corresponding to G₀/G₁ and G₂/M cell cycle arrest. In addition, 5-8FcisR and 6-10BcisR cells in 3D forms synergistically strengthened endurance of their spheroids to cisplatin treatment as observed by increased resistance index (RI) and decreased apoptosis. Mechanistically, the aberrantly expressed integrin α5 decreased drug susceptibility in NPC spheroids by inactivating ERK and inhibition of caspase-3 inducing apoptosis. Furthermore, the effect of integrin α5 inducing intrinsic resistance was verified via treatment with ATN-161, a peptide inhibitor for integrin α5β1. The results showed dramatic reduction in integrin α5 expression, reversal of ERK phosphorylation and caspase-3 cleavage, together with elevated cisplatin sensitivity, indicating regulation of innate drug resistance via integrin α5. Taken together, our findings suggest that integrin α5 could act as a promising target to enhance the chemotherapeutic sensitivity in NPC.

Biomechanical Properties of Cancer Cells

Since the crucial role of the microenvironment has been highlighted, many studies have been focused on the role of biomechanics in cancer cell growth and the invasion of the surrounding environment. Despite the search in recent years for molecular biomarkers to try to classify and stratify cancers, much effort needs to be made to take account of morphological and nanomechanical parameters that could provide supplementary information concerning tissue complexity adaptation during cancer development. The biomechanical properties of cancer cells and their surrounding extracellular matrix have actually been proposed as promising biomarkers for cancer diagnosis and prognosis. The present review first describes the main methods used to study the mechanical properties of cancer cells. Then, we address the nanomechanical description of cultured cancer cells and the crucial role of the cytoskeleton for biomechanics linked with cell morphology. Finally, we depict how studying interaction of tumor cells with their surrounding microenvironment is crucial to integrating biomechanical properties in our understanding of tumor growth and local invasion.

Nanomechanics in Monitoring the Effectiveness of Drugs Targeting the Cancer Cell Cytoskeleton

Increasing attention is devoted to the use of nanomechanics as a marker of various pathologies. Atomic force microscopy (AFM) is one of the techniques that could be applied to quantify the nanomechanical properties of living cells with a high spatial resolution. Thus, AFM offers the possibility to trace changes in the reorganization of the cytoskeleton in living cells. Impairments in the structure, organization, and functioning of two main cytoskeletal components, namely, actin filaments and microtubules, cause severe effects, leading to cell death. That is why these cytoskeletal components are targets for antitumor therapy. This review intends to describe the gathered knowledge on the capability of AFM to trace the alterations in the nanomechanical properties of living cells induced by the action of antitumor drugs that could translate into their effectiveness.

Cellular, molecular and genetical overview of avian tibial dyschondroplasia

Tibial dyschondroplasia (TD) is an intractable avian bone disease that causes severe poultry economic losses. The pathogenicity of TD is unknown. Therefore, TD disease has not been evacuated yet. Based on continuous research findings, we have gone through the molecular and cellular insight into the TD and proposed possible pathogenicity for future studies. Immunity and angiogenesis-related genes expressed in the erythrocytes of chicken, influenced the apoptosis of chicken chondrocytes to cause TD. TD could be defined as the irregular, unmineralized and un-vascularized mass of cartilage, which is caused by apoptosis, degeneration and insufficient blood supply at the site of the chicken growth plate. The failure of angiogenesis attributed improper nutrients supply to the chondrocytes; ultimately, bone development stopped, poor calcification of cartilage matrix, and apoptosis of chondrocytes occurred. Recent studies explore potential signaling pathways that regulated TD in broiler chickens, including parathyroid hormone-related peptide (PTHrP), transforming growth factor β (TGF- β)/bone morphogenic proteins (BMPs), and hypoxia-inducible factor (HIF). Several studies have reported many medicines to treat TD. However, recently, rGSTA3 protein (50 μg·kg^-1) is considered the most proper TD treatment. The present review has summarized the molecular and cellular insight into the TD, which will help researchers in medicine development to evacuate TD completely.

Estrogen Receptor alpha depletion affects the biomechanical properties and cytoskeleton rearrangements in breast cancer cells

Estrogen Receptor alpha (ERα) affects the morphology of tumors, which is closely related to the biomechanical properties and the cytoskeletal proteins. In recent years, researchers have found that biomechanical properties and cytoskeletal proteins are closely related to the occurrence and development of tumors and that biomechanical properties can be used as markers for tumor development and drug resistance. The relationship between ERα expression status and biomechanical properties, cytoskeletal proteins is not known. In this study, we found that tamoxifen-resistant breast cancer cells (MCF-7/TamR) altered cell morphology and lacked of ERα expression during the process of the Tamoxifen resistance induction. To determine whether this change was influenced by ERα expression, we transiently constructed another ERα depleted model with ERα siRNA (MCF-7/ERα siRNA) and used atomic force microscope (AFM) to detect morphological and biophysical changes. The results indicated that the roughness and Young's modulus of ERα expression depleted cells were significantly increased, accompanied by rearrangement of the cytoskeletal proteins (F-actin, FLNA, α-tubulin) and the cytoskeletal regulatory protein Rho (Rac1, CDC42) decreased. Our results have demonstrated that ERα depletion affects the biomechanical properties of breast cancer cells, which are related to cytoskeletal protein rearrangement and Rho protein decreased.

Transcriptome-based screening of intracellular pathways and angiogenesis related genes at different stages of thiram induced tibial lesions in broiler chickens

Background

The Tibial dyschondroplasia (TD) in fast-growing chickens is mainly caused by improper blood circulation. The exact mechanism underlying angiogenesis and vascularization in tibial growth plate of broiler chickens remains unclear. Therefore, this research attempts to study genes involved in the regulation of angiogenesis in chicken red blood cells. Twenty-four broiler chickens were allotted into a control and thiram (Tetramethyl thiuram disulfide) group. Blood samples were collected on day 2, 6 (8- and 14-days old chickens) and 15 (23 days old chickens).

Results

Histopathology and hematoxylin and eosin (H&E) results showed that angiogenesis decreased on the 6th day of the experiment but started to recover on the 15th day of the experiment. Immunohistochemistry (IHC) results confirmed the expressions of integrin alpha-v precursor (ITGAV) and clusterin precursor (CLU). Transcriptome sequencing analysis evaluated 293 differentially expressed genes (DEGs), of which 103 up-regulated genes and 190 down-regulated genes were enriched in the pathways of neuroactive ligand receptor interaction, mitogen-activated protein kinase (MAPK), ribosome, regulation of actin cytoskeleton, focal adhesion, natural killer cell mediated cytotoxicity and the notch signalling pathways. DEGs (n = 20) related to angiogenesis of chicken erythrocytes in the enriched pathways were thromboxane A2 receptor (TBXA2R), interleukin-1 receptor type 1 precursor (IL1R1), ribosomal protein L17 (RPL17), integrin beta-3 precursor (ITGB3), ITGAV, integrin beta-2 precursor (ITGB2), ras-related C3 botulinum toxin substrate 2 (RAC2), integrin alpha-2 (ITGA2), IQ motif containing GTPase activating protein 2 (IQGAP2), ARF GTPase-activating protein (GIT1), proto-oncogene vav (VAV1), integrin alpha-IIb-like (ITGA5), ras-related protein Rap-1b precursor (RAP1B), tyrosine protein kinase Fyn-like (FYN), tyrosine-protein phosphatase non-receptor type 11 (PTPN11), protein patched homolog 1 (PTCH1), nuclear receptor corepressor 2 (NCOR2) and mastermind like protein 3 (MAML3) selected for further confirmation with qPCR. However, commonly DEGs were sarcoplasmic/endoplasmic reticulum calcium ATPase 3 (ATP2A3), ubiquitin-conjugating enzyme E2 R2 (UBE2R2), centriole cilia and spindle-associated protein (CCSAP), coagulation factor XIII A chain protein (F13A1), shroom 2 isoform X6 (SHROOM2), ras GTPase-activating protein 3 (RASA3) and CLU.

Conclusion

We have found potential therapeutic genes concerned to erythrocytes and blood regulation, which regulated the angiogenesis in thiram induced TD chickens. This study also revealed the potential functions of erythrocytes.

Graphical abstract

1. Tibial dyschondroplasia (TD) in chickens were more on day 6, which started recovering on day 15. 2. The enriched pathway observed in TD chickens on day 6 was ribosome pathway, on day 15 were regulation of actin cytoskeleton and focal adhesion pathway. 3. The genes involved in the ribosome pathways was ribosomal protein L17 (RPL17). regulation of actin cytoskeleton pathway were Ras-related C3 botulinum toxin substrate 2 (RAC2), Ras-related protein Rap-1b precursor (RAP1B), ARF GTPase-activating protein (GIT1), IQ motif containing GTPase activating protein 2 (IQGAP2), Integrin alpha-v precursor (ITGAV), Integrin alpha-2 (ITGA2), Integrin beta-2 precursor (ITGB2), Integrin beta-3 precursor (ITGB3), Integrin alpha-IIb-like (ITGA5). Focal adhesion Proto-oncogene vav (Vav-like), Tyrosine-protein kinase Fyn-like (FYN).

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

The mechanical properties of cells could serve as an indicator for disease progression and early cancer diagnosis. This study utilized atomic force microscopy (AFM) to measure the viscoelastic properties of ovarian cancer cells and then examined the association with the invasion of ovarian cancer at the level of living single cells. Elasticity and viscosity of the ovarian cancer cells OVCAR-3 and HO-8910 are significantly lower than those of the human ovarian surface epithelial cell (HOSEpiC) control. Further examination found a dramatic increase of migration/invasion and an obvious decease of microfilament density in OVCAR-3 and HO-8910 cells. Also, there was a significant relationship between viscoelastic and biological properties among these cells. In addition, the elasticity was significantly increased in OVCAR-3 and HO-8910 cells after the treatment with the anticancer compound echinomycin (Ech), while no obvious change was found in HOSEpiC cells after Ech treatment. Interestingly, Ech seemed to have no effect on the viscosity of the cells. Ech significantly inhibited the migration/invasion and significantly increased the microfilament density in OVCAR-3 and HO-8910 cells, which was significantly related with the elasticity of the cells. An increase of elasticity and a decrease of invasion were found in OVCAR-3 and HO-8910 cells after Ech treatment. Together, this study clearly demonstrated the association of viscoelastic properties with the invasion of ovarian cancer cells and shed a light on the biomechanical changes for early diagnosis of tumor transformation and progression at single-cell level.

Chemotherapeutic resistance: a nano-mechanical point of view

Chemotherapeutic resistance is one of the main obstacles for cancer remission. To understand how cancer cells acquire chemotherapeutic resistance, biochemical studies focusing on drug target alteration, altered cell proliferation, and reduced susceptibility to apoptosis were performed. Advances in nano-mechanobiology showed that the enhanced mechanical deformability of cancer cells accompanied by cytoskeletal alteration is a decisive factor for cancer development. Furthermore, atomic force microscopy (AFM)–based nano-mechanical studies showed that chemotherapeutic treatments reinforced the mechanical stiffness of drug-sensitive cancer cells. However, drug-resistant cancer cells did not show such mechanical responses following chemotherapeutic treatments. Interestingly, drug-resistant cancer cells are mechanically heterogeneous, with a subpopulation of resistant cells showing higher stiffness than their drug-sensitive counterparts. The signaling pathways involving Rho, vinculin, and myosin II were found to be responsible for these mechanical alterations in drug-resistant cancer cells. In the present review, we highlight the mechanical aspects of chemotherapeutic resistance, and suggest how mechanical studies can contribute to unravelling the multifaceted nature of chemotherapeutic resistance.

Mechanical Alteration Associated With Chemotherapeutic Resistance of Breast Cancer Cells

Background

The mechanical deformability of cancer cells has attracted particular attention as an emerging biomarker for the prediction of anti-cancer drug sensitivity. Nevertheless, it has not been possible to establish a general rubric for the identification of drug susceptibility in breast cancer cells from a mechanical perspective. In the present study, we investigated the mechanical alteration associated with resistance to adjuvant therapy in breast cancer cells.

Methods

We performed an ‘atomic force microscopy (AFM)-based nanomechanical study’ on ‘drug-sensitive (MCF-7)’ and ‘drug-resistant (MCF-7/ADR)’ breast cancer cells. We also conducted cell viability tests to evaluate the difference in doxorubicin responsiveness between two breast cancer cell lines. We carried out a wound closure experiment to investigate the motility changes associated with chemotherapeutic resistance. To elucidate the changes in molecular alteration that accompany chemotherapeutic resistance, we investigated the expression of vinculin and integrin-linked kinase-1–which are proteins involved in substrate adhesion and the actin cytoskeleton–using Western blotting analysis.

Results

A MTT assay confirmed that the dose-dependent efficacy of doxorubicin was reduced in MCF-7/ADR cells compared to that in MCF-7 cells. The wound assay revealed enhanced two-dimensional motility in the MCF-7/ADR cells. The AFM mechanical assay showed evidence that the drug-resistant breast cancer cells exhibited a significant decrease in mechanical deformability compared to their drug-sensitive counterparts. The mechanical alteration in the MCF-7/ADR cells was accompanied by upregulated vinculin expression.

Conclusions

The obtained results manifestly showed that the altered mechanical signatures–including mechanical deformability and motility–were closely related with drug resistance in the breast cancer cells. We believe that this investigation has improved our understanding of the chemotherapeutic susceptibility of breast cancer cells.

Expression of ribosomal and actin network proteins and immunochemotherapy resistance in diffuse large B cell lymphoma patients

Diffuse large B cell lymphoma (DLBCL) patients with early relapse or refractory disease have a very poor outcome. Immunochemotherapy resistance will probably, also in the era of targeted drugs, remain the major cause of treatment failure. We used proteomic mass spectrometry to analyse the global protein expression of micro-dissected formalin-fixed paraffin-embedded tumour tissues from 97 DLBCL patients: 44 with primary refractory disease or relapse within 1 year from diagnosis (REF/REL), and 53 who were progression-free more than 5 years after diagnosis (CURED). We identified 2127 proteins: 442 were found in all patients and 102 were differentially expressed. Sixty-five proteins were overexpressed in REF/REL patients, of which 46 were ribosomal proteins (RPs) compared with 2 of the 37 overexpressed proteins in CURED patients (P = 7·6 × 10^-10 ). Twenty of 37 overexpressed proteins in CURED patients were associated with actin regulation, compared with 1 of 65 in REF/REL patients (P = 1·4 × 10^-9 ). Immunohistochemical staining showed higher expression of RPS5 and RPL17 in REF/REL patients while MARCKS-like protein, belonging to the actin network, was more highly expressed in CURED patients. Even though functional studies aimed at individual proteins and protein interactions to evaluate potential clinical effect are needed, our findings suggest new mechanisms behind immunochemotherapy resistance in DLBCL.

Inositol 1, 4, 5-trisphosphate-dependent nuclear calcium signals regulate angiogenesis and cell motility in triple negative breast cancer

Increases in nuclear calcium concentration generate specific biological outcomes that differ from those resulting from increased cytoplasmic calcium. Nuclear calcium effects on tumor cell proliferation are widely appreciated; nevertheless, its involvement in other steps of tumor progression is not well understood. Therefore, we evaluated whether nuclear calcium is essential in other additional stages of tumor progression, including key steps associated with the formation of the primary tumor or with the metastatic cascade. We found that nuclear calcium buffering impaired 4T1 triple negative breast cancer growth not just by decreasing tumor cell proliferation, but also by enhancing tumor necrosis. Moreover, nuclear calcium regulates tumor angiogenesis through a mechanism that involves the upregulation of the anti-angiogenic C-X-C motif chemokine 10 (CXCL10-IP10). In addition, nuclear calcium buffering regulates breast tumor cell motility, culminating in less cell invasion, likely due to enhanced vinculin expression, a focal adhesion structural protein. Together, our results show that nuclear calcium is essential for triple breast cancer angiogenesis and cell migration and can be considered as a promising strategic target for triple negative breast cancer therapy.

Transcriptome Sequencing Reveals Key Pathways and Genes Associated with Cisplatin Resistance in Lung Adenocarcinoma A549 Cells

Acquired resistance to cisplatin-based chemotherapy frequently occurs in patients with non-small cell lung cancer, and the underlying molecular mechanisms are not well understood. The aim of this study was to investigate whether a distinct gene expression pattern is associated with acquired resistance to cisplatin in human lung adenocarcinoma. Whole-transcriptome sequencing was performed to compare the genome-wide gene expression patterns of the human lung adenocarcinoma A549 cisplatin-resistant cell line A549/DDP with those of its progenitor cell line A549. A total of 1214 differentially expressed genes (DEGs) were identified, 656 of which were upregulated and 558 were downregulated. Functional annotation of the DEGs in the Kyoto Encyclopedia of Genes and Genomes database revealed that most of the identified genes were enriched in the PI3K/AKT, mitogen-activated protein kinase, actin cytoskeleton regulation, and focal adhesion pathways in A549/DDP cells. These results support previous studies demonstrating that the pathways regulating cell proliferation and invasion confer resistance to chemotherapy. Furthermore, the results proved that cell adhesion and cytoskeleton regulation is associated with cisplatin resistance in human lung cancer. Our study provides new promising biomarkers for lung cancer prognosis and potential therapeutic targets for lung cancer treatment.

Exosome-derived microRNAs contribute to prostate cancer chemoresistance

Certain microRNAs (miRNAs) play a key role in cancer cell chemoresistance. However, the pleiotropic functions of exosome-derived miRNAs on developing chemoresistance remain unknown. In the present study, we aimed to construct potential networks of miRNAs, which derived from the exosome of chemoresistant prostate cancer (PCa) cells, with their known target genes using miRNA expression profiling and bioinformatic tools. Global miRNA expression profiles were measured by microarray. Twelve miRNAs were initially selected and validated by qRT-PCR. Known targets of deregulated miRNAs were utilized using DIANA-TarBase database v6.0. The incorporation of deregulated miRNAs and target genes into KEGG pathways were utilized using DIANA-mirPath software. To construct potential miRNA regulatory networks, the overlapping parts of miRNAs and their targer genes from the selected KEGG pathway 'PCa progression (hsa05215)' were visualized by Cytoscape software. We identified 29 deregulated miRNAs, including 19 upregulated and 10 downregulated, in exosome samples derived from two kinds of paclitaxel resistance PCa cells (PC3-TXR and DU145-TXR) compared with their parental cells (PC3 and DU145). The enrichment results of deregulated miRNAs and known target genes showed that a few pathways were correlated with several critical cell signaling pathways. We found that hub hsa-miR3176, -141-3p, -5004-5p, -16-5p, -3915, -488‑3p, -23c, -3673 and -3654 were potential targets to hub gene androgen receptor (AR) and phosphatase and tensin homolog (PTEN). Hub gene T-cell factors/lymphoid enhancer-binding factors 4 (TCF4) target genes were mainly regulated by hub hsa-miR-32-5, -141-3p, -606, -381 and -429. These results may provide a linkage between PCa chemoresistance and exosome regulatory networks and thus lead us to propose that AR, PTEN and TCF4 genes may be the important genes which are regulated by exosome miRNAs in chemoresistance cancer cells.

Nano-mechanical Phenotype as a Promising Biomarker to Evaluate Cancer Development, Progression, and Anti-cancer Drug Efficacy

Since various bio-mechanical assays have been introduced for studying mechanical properties of biological samples, much progress has been made in cancer biology. It has been noted that enhanced mechanical deformability can be used as a marker for cancer diagnosis. The relation between mechanical compliances and the metastatic potential of cancer cells has been suggested to be a promising prognostic marker. Although it is yet to be conclusive about its clinical application due to the complexity in the tissue integrity, the nano-mechanical compliance of human cell samples has been evaluated by several groups as a promising marker in diagnosing cancer development and anticipating its progression. In this review, we address the mechanical properties of diverse cancer cells obtained by atomic force microscopy-based indentation experiments and reiterate prognostic relations between the nano-mechanical compliance and cancer progression. We also review the nano-mechanical responses of cancer cells to the anti-cancer drug treatment in order to interrogate a possible use of nano-mechanical compliance as a means to evaluate the effectiveness of anti-cancer drugs.

Failure of Elevating Calcium Induces Oxidative Stress Tolerance and Imparts Cisplatin Resistance in Ovarian Cancer Cells

Cisplatin is a commonly used chemotherapeutic drug, used for the treatment of malignant ovarian cancer, but acquired resistance limits its application. There is therefore an overwhelming need to understand the mechanism of cisplatin resistance in ovarian cancer, that is, ovarian cancer cells are insensitive to cisplatin treatment. Here, we show that failure of elevating calcium and oxidative stress tolerance play key roles in cisplatin resistance in ovarian cancer cell lines. Cisplatin induces an increase in oxidative stress and alters intracellular Ca(2+) concentration, including cytosolic and mitochondrial Ca(2+) in cisplatin-sensitive SKOV3 cells, but not in cisplatin-resistant SKOV3/DDP cells. Cisplatin induces mitochondrial damage and triggers the mitochondrial apoptotic pathway in cisplatin-sensitive SKOV3 cells, but rarely in cisplatin-resistant SKOV3/DDP cells. Inhibition of calcium signaling attenuates cisplatin-induced oxidative stress and intracellular Ca(2+) overload in cisplatin-sensitive SKOV3 cells. Moreover, in vivo xenograft models of nude mouse, cisplatin significantly reduced the growth rates of tumors originating from SKOV3 cells, but not that of SKOV3/DDP cells. Collectively, our data indicate that failure of calcium up-regulation mediates cisplatin resistance by alleviating oxidative stress in ovarian cancer cells. Our results highlight potential therapeutic strategies to improve cisplatin resistance.