Heat Shock Protein 27 Phosphorylation Regulates Tumor Cell Migration under Shear Stress

Mechanical activation and expression of HSP27 in epithelial ovarian cancer

Understanding the complex biomechanical tumor microenvironment (TME) is of critical importance in developing the next generation of anti-cancer treatment strategies. This is especially true in epithelial ovarian cancer (EOC), the deadliest of the gynecologic cancers due to recurrent disease or chemoresistance. However, current models of EOC progression provide little control or ability to monitor how changes in biomechanical parameters alter EOC cell behaviors. In this study, we present a microfluidic device designed to permit biomechanical investigations of the ovarian TME. Using this microtissue system, we describe how biomechanical stimulation in the form of tensile strains upregulate phosphorylation of HSP27, a heat shock protein implicated in ovarian cancer chemoresistance. Furthermore, EOC cells treated with strain demonstrate decreased response to paclitaxel in the in vitro vascularized TME model. The results provide a direct link to biomechanical regulation of HSP27 as a mediator of EOC chemoresistance, possibly explaining the failure of such therapies in some patients. The work presented here lays a foundation to elucidating mechanobiological regulation of EOC progression, including chemoresistance and could provide novel targets for anti-cancer therapeutics.

Adaptation and Changes in Actin Dynamics and Cell Motility as Early Responses of Cultured Mammalian Cells to Altered Gravitational Vector

Cultured mammalian cells have been shown to respond to microgravity (μG), but the molecular mechanism is still unknown. The study we report here is focused on molecular and cellular events that occur within a short period of time, which may be related to gravity sensing by cells. Our assumption is that the gravity-sensing mechanism is activated as soon as cells are exposed to any new gravitational environment. To study the molecular events, we exposed cells to simulated μG (SμG) for 15 min, 30 min, 1 h, 2 h, 4 h, and 8 h using a three-dimensional clinostat and made cell lysates, which were then analyzed by reverse phase protein arrays (RPPAs) using a panel of 453 different antibodies. By comparing the RPPA data from cells cultured at 1G with those of cells under SμG, we identified a total of 35 proteomic changes in the SμG samples and found that 20 of these changes took place, mostly transiently, within 30 min. In the 4 h and 8 h samples, there were only two RPPA changes, suggesting that the physiology of these cells is practically indistinguishable from that of cells cultured at 1 G. Among the proteins involved in the early proteomic changes were those that regulate cell motility and cytoskeletal organization. To see whether changes in gravitational environment indeed activate cell motility, we flipped the culture dish upside down (directional change in gravity vector) and studied cell migration and actin cytoskeletal organization. We found that compared with cells grown right-side up, upside-down cells transiently lost stress fibers and rapidly developed lamellipodia, which was supported by increased activity of Ras-related C3 botulinum toxin substrate 1 (Rac1). The upside-down cells also increased their migratory activity. It is possible that these early molecular and cellular events play roles in gravity sensing by mammalian cells. Our study also indicated that these early responses are transient, suggesting that cells appear to adapt physiologically to a new gravitational environment.

Integrity and wound healing of rainbow trout intestinal epithelial cell sheets at hypo-, normo-, and hyper-thermic temperatures

How temperature influences fish physiological systems, such as the intestinal barrier, is important for understanding and alleviating the impact of global warming on fish and aquaculture. Monolayers of the rainbow trout cell line, RTgutGC, with or without linear 500 μm wide gaps (wounds) were the in vitro models used to study the integrity and healing of intestinal epithelial sheets at different temperatures. Cultures at hypothermic (4 °C) or hyperthermic (≥ 26 °C) temperatures were compared to normothermic control cultures (18-22 °C). Monolayers remained intact for at least a week at temperatures from 4 to 28 °C, but had lost their integrity after 3 h at 32 °C as the cells pulled away from one another and from the plastic surface. F-actin appeared as prominent stress fibers in cells at 28 °C and as blobs in cells at 32 °C. At normothermia and at 26 °C, cells migrated as sheets into the gaps and closed (healed) the gaps within 5-6 days. By contrast, wounds took 14 days to heal at 4 °C. At 28 °C some cells migrated into the gap in the first few days but mainly as single cells rather than collectively and wounds never healed. When monolayers with wounds were challenged at 32 °C for 3 h and returned to 18-22 °C, cells lost their shape and actin organization and over the next 6 days detached and died. When monolayers were subjected to 26 °C for 24 h and challenged at 32 °C for 3 h prior to being placed at 18-22 °C, cell shape and actin cytoskeleton were maintained, and wounds were healed over 6 days. Thus, intestinal epithelial cells become thermostabilized for shape, cytoskeleton and migration by a prior heat exposure.

Renal tumor biomarkers (Review)

One of the most common types of cancer worldwide (9th most commonly diagnosed) is renal cell carcinoma (RCC). It is more common in developed countries and it usually develops in individuals between 60 and 70 years of age. The earlier the disease is identified, the lower the morbidity. Therefore molecular markers that exist in blood and urine may be used for earlier detection and diagnosis but also for the follow-up of the patient after treatment, whether surgical or oncological. The trend is to analyze the gene and protein expression as they constitute a source for new biomarkers. These markers are promising but in clinical practice regarding disease management, they are rarely used. Biological markers can be employed in many tumors because they can identify the prognostic value for individual treatment. However, markers for RCC are not validated, and their analysis is currently under investigation. Previous findings have demonstrated that the metastatic potential of RCC can be predicted using the biological features of the tumor cell. It is believed that the transformation from epithelial to mesenchymal phenotype gives the tumor cell the ability to metastasize. The purpose of this review was to identify the most valuable tumor markers that can be clinically used for the prognosis, treatment and follow-up of patients with renal tumors.

T-cadherin inhibits invasion and migration of endometrial stromal cells in endometriosis

STUDY QUESTION

What is the expression level of T-cadherin in endometriosis, and does T-cadherin play a role in regulating invasion and migration of endometrial stromal cells?

SUMMARY ANSWER

T-cadherin expression was reduced in ectopic endometriotic lesions compared to eutopic endometrium, and T-cadherin overexpression inhibited the invasion and migration of endometrial stromal cells.

WHAT IS KNOWN ALREADY

Endometriosis is a disease that involves active cell invasion and migration. T-cadherin can inhibit cell invasion, migration and proliferation in various cancer cells, but its role in endometriosis has not been investigated.

STUDY DESIGN, SIZE, DURATION

We explored the expression status of T-cadherin in 40 patients with and 24 without endometriosis. We also isolated endometrial stromal cells to study the invasion, migration and signaling pathway regulation of T-cadherin overexpression.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were recruited at the Guangzhou Women and Children's Medical Center to study the expression levels of T-cadherin. The expression of T-cadherin was detected by immunohistochemistry staining and western blot. H-score was used to evaluate the staining intensity of T-cadherin. The correlation between T-cadherin expression levels (H-score) and endometriosis patients' age, stage, lesion size and adhesion was analyzed. Endometrial stromal cells from patients with and without endometriosis were isolated, and cell invasion and migration were detected by transwell assays after T-cadherin overexpression. The expression of vimentin in T-cadherin-overexpressed cells was detected by western blot. After T-cadherin overexpression, the phosphorylation profile of signaling pathway proteins was detected with the Proteome Profiler Human Phospho-Kinase Array Kit.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no difference in the expression of T-cadherin in the normal endometrium of control patients and the eutopic endometrium of endometriotic patients, but it was significantly decreased in the ectopic endometrium of endometriotic patients, compared with control endometrium and eutopic endometrium of endometriosis patients (P < 0.0001, for both). Western blot analysis also showed that the expression of T-cadherin was decreased in ectopic endometriotic lesions, but not the normal control endometrium or the endometriotic eutopic endometrium. The results of transwell assays indicated that T-cadherin overexpression inhibited the invasion and migration of endometrial stromal cells. In addition, T-cadherin overexpression promoted the phosphorylation of HSP27 (S78/S82) and JNK 1/2/3 (T183/Y185, T221/Y223) and decreased the expression of vimentin, MMP2 and MMP9 in eutopic endometriosis stromal cells.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The control group were patients with benign gynecological conditions (e.g. uterus myoma, endometrial or cervical polyp), which may have genetic or epigenetic variations associated with T-cadherin expression and signaling pathways. The case numbers of involved endometriosis and control patients were limited. This study only used endometrial stromal cells from patients with or without endometriosis. Ideally, ectopic endometrial stromal cells of the ovarian endometriotic lesions should also be utilized to explore the function of T-cadherin.

WIDER IMPLICATIONS OF THE FINDINGS

Further investigation of the role of T-cadherin in endometriosis may generate new potential therapeutic targets for this complex disorder.

STUDY FUNDING AND COMPETING INTEREST(S)

This study was supported by the Natural Science Foundation of Guangdong Province (2016A030313495), National Natural Science Foundation of China (81702567, 81671406, 31871412), the Science and Technology Programs of Guangdong (2017A050501021), Medical Science Technology Research Fund of Guangdong Province (A2018075), the Science and Technology Programs of Guangzhou City (201704030103), Internal Project of Family Planning Research Institute of Guangdong Province (S2018004), Post-doc initiation fund of Guangzhou (3302) and Post-doc science research initiation fund of Guangzhou Women and Children's Medical Center (20160322). There are no conflicts of interest.

Linking metabolic dysfunction with cardiovascular diseases: Brn-3b/POU4F2 transcription factor in cardiometabolic tissues in health and disease

Metabolic and cardiovascular diseases are highly prevalent and chronic conditions that are closely linked by complex molecular and pathological changes. Such adverse effects often arise from changes in the expression of genes that control essential cellular functions, but the factors that drive such effects are not fully understood. Since tissue-specific transcription factors control the expression of multiple genes, which affect cell fate under different conditions, then identifying such regulators can provide valuable insight into the molecular basis of such diseases. This review explores emerging evidence that supports novel and important roles for the POU4F2/Brn-3b transcription factor (TF) in controlling cellular genes that regulate cardiometabolic function. Brn-3b is expressed in insulin-responsive metabolic tissues (e.g. skeletal muscle and adipose tissue) and is important for normal function because constitutive Brn-3b-knockout (KO) mice develop profound metabolic dysfunction (hyperglycaemia; insulin resistance). Brn-3b is highly expressed in the developing hearts, with lower levels in adult hearts. However, Brn-3b is re-expressed in adult cardiomyocytes following haemodynamic stress or injury and is necessary for adaptive cardiac responses, particularly in male hearts, because male Brn-3b KO mice develop adverse remodelling and reduced cardiac function. As a TF, Brn-3b regulates the expression of multiple target genes, including GLUT4, GSK3β, sonic hedgehog (SHH), cyclin D1 and CDK4, which have known functions in controlling metabolic processes but also participate in cardiac responses to stress or injury. Therefore, loss of Brn-3b and the resultant alterations in the expression of such genes could potentially provide the link between metabolic dysfunctions with adverse cardiovascular responses, which is seen in Brn-3b KO mutants. Since the loss of Brn-3b is associated with obesity, type II diabetes (T2DM) and altered cardiac responses to stress, this regulator may provide a new and important link for understanding how pathological changes arise in such endemic diseases.

Differential phosphorylation regulates the shear stress-induced polar activity of Rho-specific guanine nucleotide dissociation inhibitor α

The activity of Rho-specific guanine nucleotide dissociation inhibitor α (RhoGDIα) is regulated by its own phosphorylation at different amino acid sites. These phosphorylation sites may have a crucial role in local Rho GTPases activation during cell migration. This paper is designed to explore the influence of phosphorylation on shear stress-induced spatial RhoGDIα activation. Based on the fluorescence resonance energy transfer biosensor sl-RhoGDIα, which was constructed to test the RhoGDIα activity in living cells, new RhoGDIα phosphomimetic mutation (sl-S101E/S174E, sl-Y156E, sl-S101E, sl-S174E) and phosphorylation-deficient mutation (sl-S101A/S174A, sl-Y156A, sl-S101A, sl-S174A) biosensors were designed to test their effects on RhoGDIα activation upon shear stress application in human umbilical vein endothelial cells (HUVECs). The results showed lower RhoGDIα activity at the downstream of HUVECs (the region from the edge of the nucleus to the edge of the cell along with the flow). The overall decrease in RhoGDIα activity was inhibited by Y156A-mutant, whereas the polarized RhoGDIα and Rac1 activity were blocked by S101A/S174A mutant. It is concluded that the Tyr156 phosphorylation mainly mediates shear stress-induced overall RhoGDIα activity, while Ser101/Ser174 phosphorylation mediates its polarization. This study demonstrates that differential phosphorylation of RhoGDIα regulates shear stress-induced spatial RhoGDIα activation, which could be a potential target to control cell migration.

Increased temperature-related adeno-associated virus vectors transduction of ovarian cancer cells - essential signatures of AAV receptor and heat shock proteins

Recombinant adeno-associated viruses (rAAVs) are becoming more commonly used in clinical trials involving gene therapy. Additionally AAV-based drugs have already been registered. Gene therapy aims to increase transduction efficiency, increase in vivo selectivity and reduce side effects. One approach to achieve this is the use of physical factors, such as temperature or more specifically, hyperthermia, which is already utilized in oncology. The aim of the present study was to investigate the effect of hyperthermic conditions (40°C and 43°C) on the rAAV transduction efficiency of ovarian cancer cells (Caov-3 and NIH:OVCAR-3) and non-cancerous cells (AAV-293). The present study was designed to identify functional associations between the level of gene transfer and the expression of representative genes for rAAV transmission (AAVR (AAV receptor), heparan sulfate proteoglycan (HSPG) 1 and HSPG2) and heat shock proteins (HSPs). The expressions of selected genes were measured via reverse transcription-quantitative PCR and cell adhesion/invasion chamber tests were also performed. The results revealed that ovarian cancer cell lines were more efficiently transduced with rAAV vectors at an elevated temperature. Additionally, the expression patterns of AAVR, HSPG1 and HSPG2 genes were different between the tested lines. The expression of certain receptors in ascites-derived NIH:OVCAR-3 ovarian cancer cells was higher compared with tumor-derived Caov-3 cells at 37, 40 and 43°C, which indicates a higher transduction efficiency in the formerly mentioned cells. Ascites-derived ovarian cancer cells were characterized by high expressions of HSP40, HSP90 and HSP70 families. Lower levels of HSP expression were demonstrated in less-effectively transduced Caov-3 cells. Furthermore, expressions of the examined genes changed with increasing temperature. The results indicated that temperature-dependent transduction is associated with the expression of the rAAV receptor and HSP genes. The results of the current study may aid the design of effective protocols for ovarian cancer gene therapy.