Phosphoinositide 3-kinases in cell migration. Biol Cell. 2009;101:13-29. [PMID: 19055486 DOI: 10.1042/bc20080079]

Synergistic effect of PIP2 and PIP3 on membrane-induced phase separation of integrin complexes

The assembly of integrin adhesion complexes at the inner leaflet of the plasma membrane regulates cell adhesion to the extracellular matrix. The multivalent protein interactions within the complexes and with the cell membrane display characteristics of membrane-associated biomolecular condensates driven by liquid-liquid phase separation. The composition of lipids and the distribution of the cell membrane are crucial for forming integrin adhesion complexes. Here, we report that phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol (3,4,5)-trisphosphate (PIP3) in the model membrane synergistically regulate the formation of membrane-induced integrin adhesion condensates, which consist of β1 tails, kindlin, talin, paxillin, and focal adhesion kinase. We show that the preferential bindings of kindlin to PIP3 and talin to PIP2 enhance their recruitment to the membrane, which in turn increases the probability of membrane-associated phase separation. Our results indicate that modulating the intricate balance of membrane composition is a strategy to localize integrin adhesion complexes and optimize their density on lipid membranes.

Cold Atmospheric Plasma Jet Promotes Wound Healing Through CK2-Coordinated PI3K/AKT and MAPK Signaling Pathways

The promising role of cold atmospheric plasma jet (CAPJ) treatment in promoting wound healing has been widely documented in therapeutic implications. However, the fact that not all subjects respond equally to CAPJ necessitates the investigation of the underlying cellular mechanisms, which have been rarely understood so far. Given that wound healing is a complex and prolonged process, post plasma-activated medium (PAM) treated keratinocytes were collected at two time points, 2 h (receiving) and 24 h (recovery), for (phospho)proteomic analysis to systematically dissect the molecular basis of CAPJ-promoted wound healing. The receiving (phospho)proteomics datasets, referred to the time point of 2 h, revealed an apparent increase in the phosphorylation of CK2 and its-mediated PI3K/AKT and MAPK signaling pathways, accompanied by a prompted downstream physiological response of cell migration. Additionally, incorporating the network analysis of predicted kinases and their direct interactors, we reiterated that CAPJ influenced cell growth and migration, thereby paving the way for its role in subsequent wound healing processes. Further determining the proteome profiles at recovery phase, which is the time point of 24 h, displayed a totally different view from the receiving proteome which had almost no change. The upregulation of ROBOs/SLITs expression and vesicle trafficking and fusion-related proteins, along with the abundant presence of 14-3-3 family proteins, indicated that the persistent effect of PAM on the wound healing process could potentially promote keratinocyte-fibroblast cross talk and stimulate extracellular matrix synthesis upon epithelialization. Consistent with proteome patterns, CAPJ-treated wound tissues indeed showed a denser and well-organized extracellular matrix architecture, implying hastened epithelialization during wound healing. Collectively, we delineated the molecular basis of CAPJ-accelerated wound healing at early and late responses, providing valuable insights for treatment selection and the development of therapeutic strategies to achieve better outcomes.

Large-scale control over collective cell migration using light-activated epidermal growth factor receptors

Receptor tyrosine kinases (RTKs) play key roles in coordinating cell movement at both single-cell and tissue scales. The recent development of optogenetic tools for controlling RTKs and their downstream signaling pathways suggests that these responses may be amenable to engineering-based control for sculpting tissue shape and function. Here, we report that a light-controlled epidermal growth factor (EGF) receptor (OptoEGFR) can be deployed in epithelial cells for precise, programmable control of long-range tissue movements. We show that in OptoEGFR-expressing tissues, light can drive millimeter-scale cell rearrangements to densify interior regions or produce rapid outgrowth at tissue edges. Light-controlled tissue movements are driven primarily by phosphoinositide 3-kinase (PI3K) signaling, rather than diffusible ligands, tissue contractility, or ERK kinase signaling as seen in other RTK-driven migration contexts. Our study suggests that synthetic, light-controlled RTKs could serve as a powerful platform for controlling cell positions and densities for diverse applications, including wound healing and tissue morphogenesis.

Rhamnogalacturonan promotes intestinal mucosal repair through increased cell migration

Mucosal healing is the primary goal for inflammatory bowel disease (IBD) treatment. We previously showed the direct beneficial effects of rhamnogalacturonan (RGal) on intestinal epithelial barrier function. Here, we aimed to evaluate the effect of RGal in intestinal epithelial wound healing. Confluent cancer cell lines and colonoid monolayers were wounded, treated with RGal for 48 h, and assessed using a live cell imaging system. Proliferation and apoptosis of cells were evaluated using 5-ethynyl-2'-deoxyuridine (EdU) and TUNEL assays, respectively. Inhibitors were used to determine the receptor and signaling pathways involved. Female and male mice with DSS-induced colitis were treated orally with RGal for 7 days during the recovery phase. RGal enhanced wound healing in Caco-2, T84, and primary cells by increasing cell migration. Inhibition of pretranscriptional signaling pathways FAK, Src, PI3K, Rho family, and JNK reversed the RGal-induced wound healing. RNAseq data from Caco-2 and primary cells treated with RGal showed the upregulation of the NF-κB pathway at 12 h. Actinomycin D, Bay 11-7082 or JSH-23, and NS-398 treatment significantly reversed the effect of RGal on wound healing, confirming that the response was also transcriptionally dependent and involved NF-κB signaling and downstream COX-2 protein activity. RGal treatment of male mice enhanced recovery from DSS colitis. RGal promoted wound healing in cancer and primary cells by increasing cell migration and accelerated epithelial mucosal healing in male mice. Our findings show a novel mechanism of action of RGal in wound healing that could help in mucosal healing and the resolution of intestinal inflammation.NEW & NOTEWORTHY RGal increases wound healing in colon cancer cell lines and primary cells through increased cell migration and participation of important pretranscriptional signaling pathways and the transcription factor NF-κB. In addition, RGal also accelerates intestinal mucosal healing of male mice with DSS-induced colitis.

Pharmacological targeting of ECM homeostasis, fibroblast activation and invasion for the treatment of pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease with a dismal prognosis. While the standard-of-care (SOC) drugs approved for IPF represent a significant advancement in antifibrotic therapies, they primarily slow disease progression and have limited overall efficacy and many side effects. Consequently, IPF remains a condition with high unmet medical and pharmacological needs.

AREAS COVERED

A wide variety of molecules and mechanisms have been implicated in the pathogenesis of IPF, many of which have been targeted in clinical trials. In this review, we discuss the latest therapeutic targets that affect extracellular matrix (ECM) homeostasis and the activation of lung fibroblasts, with a specific focus on ECM invasion.

EXPERT OPINION

A promising new approach involves targeting ECM invasion by fibroblasts, a process that parallels cancer cell behavior. Several cancer drugs are now being tested in IPF for their ability to inhibit ECM invasion, offering significant potential for future treatments. The delivery of these therapies by inhalation is a promising development, as it may enhance local effectiveness and minimize systemic side effects, thereby improving patient safety and treatment efficacy.

Comparative transcriptomic analysis validates iPSC derived in-vitro progressive fibrosis model as a screening tool for drug discovery and development in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, immune dysregulation, and systemic fibrosis. Research on SSc has been hindered largely by lack of relevant models to study the progressive nature of the disease and to recapitulate the cell plasticity that is observed in this disease context. Generation of models for fibrotic disease using pluripotent stem cells is important for recapitulating the heterogeneity of the fibrotic tissue and are a potential platform for screening anti-fibrotic drugs. We previously reported a novel in-vitro model for fibrosis using induced pluripotent stem cell-derived mesenchymal cells (iSCAR). Here we report the generation of a "scar-like phenotype" when iPSC derived mesenchymal cells are cultured on hydrogel that mimicks a wound healing/scarring response (iSCAR). First, we performed RNA sequencing (RNA-seq) based transcriptome profiling of iSCAR culture at 48 h and 13 days to characterize early and latestage scarring phenotypes. The next generation RNA-seq of these iSCAR culture at different timepoints detected expression 92% of early "scar associated" genes and 85% late "scar associated" genes, respectively. Comparative transcriptomic analysis of a gene level SSc compendium matrix to the iSCAR wound associated model revealed genes common in both data sets. Early scar formation genes showed biological processes of hypoxia (27.5%), vascular development (13.7%) and glycolysis (27.5), while late scar formation showed genes associated with senescence (22.6%). Next we show the effects of two different antifibrotic compounds to validate the utility of the model as a screening tool to study early and late-stagelate-stage fibrosis. An autotaxin inhibitor was used to validate the iSCAR late stage fibrotic model (iSCAR-T) and an antifibrotic tool screening compound of unknown mechanism (EX00015097) was used to study and validate both early (iSCAR-P) and late-stage (iSCAR-T) fibrosis in the iSCAR model.

Targeting the RAS upstream and downstream signaling pathway for cancer treatment

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

A novel mutation in PTEN in anaplastic thyroid carcinoma: A case report

Anaplastic thyroid cancer (ATC) is a rare disease with a poor prognosis and accounts for a high proportion of thyroid cancer deaths. The present study reported on a 56-year-old male patient with ATC and examined the clinical manifestations, pathological features, differential diagnosis and genetic mutations. Immunohistochemical analysis showed positivity for vimentin, Ki-67 and cytokeratin in the tumor specimen. In addition, pathological mitotic figures of tumor cells and intra-lymph node metastasis were observed. Genetic analysis revealed the presence of a novel mutation (c.388C>T, p.R130X) in exon 5 of the phosphatase and tensin homolog (PTEN) gene, which was first detected in ATC. Gene conservation analysis showed that R130 is a highly conserved amino acid. Protein structure model predictions implied that p.R130X mutation results in a severe defect of the C2 domain and the TAD domain of PTEN, which may be a reason for the high malignancy of the tumor. The present case report highlights a novel mutation of PTEN in ATC, which expands the molecular spectrum of PTEN and further underlines the importance of PTEN.

Large-scale control over collective cell migration using light-controlled epidermal growth factor receptors

Receptor tyrosine kinases (RTKs) are thought to play key roles in coordinating cell movement at single-cell and tissue scales. The recent development of optogenetic tools for controlling RTKs and their downstream signaling pathways suggested these responses may be amenable to engineering-based control for sculpting tissue shape and function. Here, we report that a light-controlled EGF receptor (OptoEGFR) can be deployed in epithelial cell lines for precise, programmable control of long-range tissue movements. We show that in OptoEGFR-expressing tissues, light can drive millimeter-scale cell rearrangements to densify interior regions or produce rapid outgrowth at tissue edges. Light-controlled tissue movements are driven primarily by PI 3-kinase signaling, rather than diffusible signals, tissue contractility, or ERK kinase signaling as seen in other RTK-driven migration contexts. Our study suggests that synthetic, light-controlled RTKs could serve as a powerful platform for controlling cell positions and densities for diverse applications including wound healing and tissue morphogenesis.

PIK Your Poison: The Effects of Combining PI3K and CDK Inhibitors against Metastatic Cutaneous Squamous Cell Carcinoma In Vitro

Cutaneous squamous cell carcinoma (cSCC) is a very common skin malignancy with poor prognosis for patients with locally advanced or metastatic cSCC (mcSCC). PI3K/AKT/mTOR and cell cycle signalling pathways are often dysregulated in mcSCC. A combination drug approach has been theorised to overcome the underwhelming clinical performance of targeted inhibitors as single agents. This study investigates the potential of targeted inhibition of the p110α-subunit of PI3K with PIK-75 or BGT226 (P13Ki), and of CDK1/2/5/9 with dinaciclib (CDKi) as single agents and in combination. The patient-derived mcSCC cell lines, UW-CSCC1 and UW-CSCC2, were used to assess cell viability, migration, cell signalling, cell cycle distribution, and apoptosis. PIK-75, BGT226, and dinaciclib exhibited strong cytotoxic potency as single agents. Notably, the non-malignant HaCaT cell line was unaffected. In 2D cultures, PIK-75 synergistically enhanced the cytotoxic effects of dinaciclib in UW-CSCC2, but not UW-CSCC1. Interestingly, this pattern was reversed in 3D spheroid models. Despite the combination of PIK-75 and dinaciclib resulting in an increase in cell cycle arrest and apoptosis, and reduced cell motility, these differences were largely negligible compared to their single-agent counterpart. The differential responses between the cell lines correlated with driver gene mutation profiles. These findings suggest that personalised medicine approaches targeting PI3K and CDK pathways in combination may yield some benefit for mcSCC, and that more complex 3D models should be considered for drug responsiveness studies in this disease.

Prevalence and prognosis of PIK3CA mutations in Bulgarian patients with metastatic breast cancer receiving endocrine therapy in first-line setting

BACKGROUND AND AIMS

In approximately 40% of patients with HER2-negative/HR-positive breast cancer tumors, the PIK3CA gene is mutated. Despite this, clinical outcomes vary between studies in this cohort. We aimed to ascertain the prevalence of PIK3CA mutations in patients with metastatic HR+/HER2- breast in Bulgaria, as well the evaluation and comparison of progression free survival (PFS) between wild-type (WT) and mutation-positive groups in the real-world setting.

METHODS

Three oncology centers in Bulgaria collected 250 tissue samples between 2016 and 2022 for this multicentric retrospective study. PIK3CA mutations were identified using Real-Time qPCR. The median follow-up period was 35 months.

RESULTS

The mean age of the mutant cohort was 57.6 ± 11.6 years, compared to 56.5 ± 12.2 years for the WT cohort (p = .52). The percentage of patients with visceral metastasis was 58.8% (n = 147). Approximately 84.3% (n = 210) of the patients had reached postmenopause. 29.2% (n = 73) of the patients had PIK3CA mutations. The predominant mutation was present in exon 20, H1047R (46.5%). We found a significant correlation only between the presence of a mutation and the metastatic diseases at diagnosis (p = .002). As first-line therapy, 67.1% of patients received endocrine therapy (ET) plus cyclin dependent kinase (CDK4/6) inhibitor, while the remainder received ET alone. The median PFS of patients in the group with the mutation was 32 months (95%, CI: 22-40) compared to 24 months in the WT cohort ((95%, CI: 21-36) (p = .45)); HR = 0.86 (95%, CI: 0.5-1.3) (p = .46). We corroborated our conclusion using propensity matching score analysis, (36 months [95% CI: 20-40] vs. 26 months [95% CI: 21-38], [p = .69]).

CONCLUSIONS

We found that the prevalence of PIK3CA mutations in our patients was comparable to what has been reported in other nations. Our results suggest that PIK3CA mutational status has no bearing to ET efficacy in first-line setting.

Short-chain fatty acids stimulate dendrite elongation in dendritic cells by inhibiting histone deacetylase

Dendritic cells activate immune responses by presenting pathogen-derived molecules. The dendrites of dendritic cells contribute to the incorporation of foreign antigens or presenting antigens to T cells. Short-chain fatty acids (SCFAs), such as acetic, propionic, butyric and valeric acids, have many effects on immune responses by activating specific receptors or inhibiting a histone deacetylase (HDAC), although their effect on dendrite formation in dendritic cells is unknown. In the present study, we aimed to investigate the effect of SCFAs on dendrite elongation using a dendritic cell line (DC2.4 cells) and mouse bone marrow-derived dendritic cells. We found that SCFAs induced dendrite elongation. The elongation was reduced by inhibitors of Src family kinase (SFK), phosphatidylinositol-3 kinase (PI3K), Rho family GTPases (Cdc42, Rac1) or actin polymerization, indicating that SCFAs promote dendrite elongation by activating actin polymerization via the SFK/PI3K/Rho family GTPase signaling pathway. We showed that agonists for SCFA receptors GPR43 and GPR109a did not promote dendrite elongation. By contrast, HDAC inhibitors, including trichostatin A, promoted dendrite elongation in DC2.4 cells, and the promoting activity of trichostatin A was decreased by inhibiting the SFK/PI3K/Rho family GTPase signaling pathway or actin polymerization. Furthermore, DC2.4 cells treated with valeric acid showed enhanced uptake of soluble proteins, insoluble beads and Staphylococcus aureus. We also found that treatment with valeric acid enhanced major histocompatibility complex class II-mediated antigen presentation in bone marrow-derived dendritic cells. These results suggest that SCFAs promote dendrite elongation by inhibiting HDAC, stimulating the SFK/PI3K/Rho family pathway and activating actin polymerization, resulting in increased antigen uptake and presentation in dendritic cells.

Phosphoinositide Signaling in Immune Cell Migration

In response to different immune challenges, immune cells migrate to specific sites in the body, where they perform their functions such as defense against infection, inflammation regulation, antigen recognition, and immune surveillance. Therefore, the migration ability is a fundamental aspect of immune cell function. Phosphoinositide signaling plays critical roles in modulating immune cell migration by controlling cell polarization, cytoskeletal rearrangement, protrusion formation, and uropod contraction. Upon chemoattractant stimulation, specific phosphoinositide kinases and phosphatases control the local phosphoinositide levels to establish polarized phosphoinositide distribution, which recruits phosphoinositide effectors to distinct subcellular locations to facilitate cell migration. In this Special Issue of "Molecular Mechanisms Underlying Cell Adhesion and Migration", we discuss the significance of phosphoinositide production and conversion by phosphoinositide kinases and phosphatases in the migration of different types of immune cells.

IDO blockade negatively regulates the CTLA-4 signaling in breast cancer cells

Cancer is classified into metabolic and/or genetic disorders; notably, the tryptophan catabolism pathway is vital in different cancer types. Here, we focused on the interaction and molecular connection between the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) receptor and indoleamine-2,3-dioxygenase (IDO) enzyme. To test the impact of the selected immunotherapies on breast cancer cell migration and cell survival, we used in vitro assays. Also, we test the impact of anti-CTLA-4 antibody on the IDO-positive cells. The results of cell migration and clonogenic assays showed that anti-CTLA-4 antibody reduces cancer cell migration and clonogenic abilities of murine breast cancer cells. In addition, the result of flow cytometry showed that the anti-CTLA-4 antibody did not change the percentage of IDO-positive cancer cells. Notably, administrating an IDO blocker, 1-Methyl-DL-tryptophan (1MT), reduces the efficiency of the antiCTLA-4 antibody. The enzymatic blocking of the IDO reduces the efficiency of the anti-CTLA-4 antibody on cell migration and clonogenic abilities suggesting that there is an inhibitory interaction at the molecular level between functions of CTLA-4 and IDO. It is unclear via which mechanism(s) IDO interacts with CTLA-4 signaling and also why blocking IDO makes disruption in CTLA-4 signaling in cancer cells. Indeed, evaluating the role of IDO in CTLA-4 signaling in cancer cells may assist in clarifying a poor response to CTLA-4 immunotherapies by some patients. Hence, further investigation of the molecular interaction between CTLA-4 and IDO might help to improve the efficiency of CTLA-4 immunotherapy.

Cardiometabolic health, menopausal estrogen therapy and the brain: How effects of estrogens diverge in healthy and unhealthy preclinical models of aging

Research in preclinical models indicates that estrogens are neuroprotective and positively impact cognitive aging. However, clinical data are equivocal as to the benefits of menopausal estrogen therapy to the brain and cognition. Pre-existing cardiometabolic disease may modulate mechanisms by which estrogens act, potentially reducing or reversing protections they provide against cognitive decline. In the current review we propose mechanisms by which cardiometabolic disease may alter estrogen effects, including both alterations in actions directly on brain memory systems and actions on cardiometabolic systems, which in turn impact brain memory systems. Consideration of mechanisms by which estrogen administration can exert differential effects dependent upon health phenotype is consistent with the move towards precision or personalized medicine, which aims to determine which treatment interventions will work for which individuals. Understanding effects of estrogens in both healthy and unhealthy models of aging is critical to optimizing the translational link between preclinical and clinical research.

Tuning Water-Resistant Networks in Mussel-Inspired Hydrogels for Robust Wet Tissue and Bioelectronic Adhesion

Hydrogels with robust wet adhesion are desirable for applications in aqueous environments. Wet adhesion arising from synergy between hydrophobic and catechol components in mussel foot proteins has been highlighted. However, optimizing hydrogels with multiple components is challenging because of their complex structure-property relationships. Herein, high-throughput screening of a series of hydrophobic alkyl monomers and adhesive catechol derivatives was used to systematically develop wet adhesive hydrogels. Short alkyl chains promote wet adhesion by repelling water at the adhesive interface, whereas long alkyl chains form strong hydrophobic interactions inside the hydrogel network that impede or dissipate energy for wet adhesion. The optimized wet adhesive hydrogel, containing short alkyl chain, was applied for rapid hemostasis and wound healing because of the synergistic effect of catechol and alkyl groups and its immunomodulation ability, which is revealed through a transcriptomic analysis. Conductive nanocomponents were incorporated into the optimized hydrogel to produce a wearable device, which was used for continuous monitoring human electrocardiogram (ECG) during swimming, and in situ epicardial ECG on a porcine living and beating heart. This study demonstrated an efficient and generalized molecular design strategy for multifunctional wet adhesive hydrogels.

Crosstalk between PI3K/Akt and Wnt/β-catenin pathways promote colorectal cancer progression regardless of mutational status

The PI3K/Akt and Wnt/β-catenin pathways play an important role in the acquisition of the malignant phenotype in cancer. However, there are few data regarding the role of the interplay between both pathways in colorectal cancer (CRC) progression. The mutational status and the clinicopathological characteristics of PI3K/Akt and Wnt/β-catenin pathways were accessed by bioinformatic analysis whereas that the impact of the interplay between the activity of both pathways to explain tumorigenic potential was performed in vitro using IGF-1 and Wnt3a treatments in CRC cell models. The mutational status of these pathways did not influence the survival of CRC patients, but an association between clinicopathological characteristics in patients with mutations in one, but not in both pathways was observed. A potentiating effect on the activation of both pathways and enhanced cellular migration and proliferation was observed when both pathways were activated simultaneously with IGF-1 and Wnt3a. In addition, these effects were hindered after pretreatment with LY294002, a specific PI3K inhibitor, suggesting some dependence between these two signaling cascades. Our findings show that, regardless of mutational status, there is an interplay between the activity of PI3K/Akt and Wnt/β-catenin pathways that contributes to events related to CRC progression and that the reversal of such events using a PI3K inhibitor highlights the value of targeting these pathways for potential directed therapies in CRC patients.

Protein Expression of PI3K/AKT/mTOR Pathway Targets Validated by Gene Expression and its Correlation with Prognosis in Canine Mammary Cancer

Mammary cancer is the main type of neoplasia in female dogs and is considered an adequate model for the biological and therapeutic study of cancer in women. The PIK3CA/AKT/mTOR pathway plays a central role in cellular homeostasis and is often dysregulated in cancer. The increased expression of PI3K protein in the literature is associated with a poor prognosis, and alterations in the PIK3CA gene can lead to changes in downstream pathways. Thus, the objective of this study was to validate the protein expression to confirm the gene expression of proteins belonging to the main pathway PI3K and PTEN, and their downstream pathways through ZEB1, ZEB2, HIF1A, VHL, CASP3 and PARP1 relating to prognosis in canine mammary cancer. For protein studies, the samples came from 58 female dogs with mammary neoplasia, immunohistochemistry was performed and its analysis by the histoscore method. For the genetic evaluation, the samples came from 13 patients, the DNA was extracted and the analysis for quantitative expression. Through immunohistochemistry, PI3K positivity was significantly associated with affected regional lymph node, distant metastasis, patients with HER2+, Triple Negative and Luminal B phenotypes, and the lowest survival rates. Through gene expression, we observed higher gene expression of ZEB2 and PARP1 both among patients who were alive and who died, which was not true for the expressions of PIK3CA and HIF1A. In conclusion, the data observed in this work are promising in the study of new molecular prognostic markers such as PI3K, ZEB2 and PARP1 for canine mammary cancer.

PI3K Isoform-Specific Regulation of Leader and Follower Cell Function for Collective Migration and Proliferation in Response to Injury

To ensure proper wound healing it is important to elucidate the signaling cues that coordinate leader and follower cell behavior to promote collective migration and proliferation for wound healing in response to injury. Using an ex vivo post-cataract surgery wound healing model we investigated the role of class I phosphatidylinositol-3-kinase (PI3K) isoforms in this process. Our findings revealed a specific role for p110α signaling independent of Akt for promoting the collective migration and proliferation of the epithelium for wound closure. In addition, we found an important role for p110α signaling in orchestrating proper polarized cytoskeletal organization within both leader and wounded epithelial follower cells to coordinate their function for wound healing. p110α was necessary to signal the formation and persistence of vimentin rich-lamellipodia extensions by leader cells and the reorganization of actomyosin into stress fibers along the basal domains of the wounded lens epithelial follower cells for movement. Together, our study reveals a critical role for p110α in the collective migration of an epithelium in response to wounding.

The emerging era of personalized medicine in advanced colorectal cancer

Colorectal cancer (CRC) is a genetically heterogeneous disease with its pathogenesis often driven by varying genetic or epigenetic alterations. This has led to a substantial number of patients developing chemoresistance and treatment failure, resulting in a high mortality rate for advanced disease. Deep molecular analysis has allowed for the discovery of key intestinal signaling pathways which impacts colonic epithelial cell fate, and the integral role of the tumor microenvironment on cancer growth and dissemination. Through transitioning pre-clinical knowledge in research into clinical practice, many potential druggable targets within these pathways have been discovered in the hopes of overcoming the roadblocks encountered by conventional therapies. A personalized approach tailoring treatment according to the histopathological and molecular features of individual tumors can hopefully translate to better patient outcomes, and reduce the rate of recurrence in patients with advanced CRC. Herein, the latest understanding on the molecular science behind CRC tumorigenesis, and the potential treatment targets currently at the forefront of research are summarized.

MicroRNAs as the critical regulators of cell migration and invasion in thyroid cancer

Thyroid cancer (TC) is one of the most frequent endocrine malignancies that is more common among females. Tumor recurrence is one of the most important clinical manifestations in differentiated TC which is associated with different factors including age, tumor size, and histological features. Various molecular processes such as genetic or epigenetic modifications and non-coding RNAs are also involved in TC progression and metastasis. The epithelial-to-mesenchymal transition (EMT) is an important biological process during tumor invasion and migration that affects the initiation and transformation of early-stage tumors into invasive malignancies. A combination of transcription factors, growth factors, signaling pathways, and epigenetic regulations affect the thyroid cell migration and EMT process. MicroRNAs (miRNAs) are important molecular factors involved in tumor metastasis by regulation of EMT-activating signaling pathways. Various miRNAs are involved in the signaling pathways associated with TC metastasis which can be used as diagnostic and therapeutic biomarkers. Since, the miRNAs are sensitive, specific, and non-invasive, they can be suggested as efficient and optimal biomarkers of tumor invasion and metastasis. In the present review, we have summarized all of the miRNAs which have been significantly involved in thyroid tumor cells migration and invasion. We also categorized all of the reported miRNAs based on their cellular processes to clarify the molecular role of miRNAs during thyroid tumor cell migration and invasion. This review paves the way of introducing a non-invasive diagnostic and prognostic panel of miRNAs in aggressive and metastatic TC patients.

27-Hydroxycholesterol induces expression of zonula occludens-1 in monocytic cells via multiple kinases pathways

Zonula occludens (ZO)-1, a tight-junction protein (TJP), is expressed in dendritic cells (DCs) but not in monocytes, and 27-hydroxycholesterol (27OHChol) drives the differentiation of monocytes into DCs. Because the effects of 27OHChol on ZO-1 are not yet clearly defined, we investigated whether 27OHChol induces expression of the TJP. The treatment of human THP-1 monocytic cells with 27OHChol resulted in the elevated transcript levels of ZO-1 but not of ZO-2 or -3. 27OHChol increased the total amount of ZO-1 protein in the cells as well as its level on the cells surface. Cholesterol, however, did not influence expression of ZO-1. And, the expression of ZO-1 protein was mediated by endoplasmic reticulum (ER)-to-Golgi body transport system. Pharmacological kinase inhibition with LY294002 (a PI3K inhibitor), U0126 (a MEK/ERK inhibitor), or PP2 (a Src family kinase inhibitor) resulted in impaired ZO-1 expression at both transcript and protein levels. Drugs that are reported to suppress DC differentiation also inhibited 27OHChol-mediated expression and the localization of ZO-1, indicating the coincidence of ZO-1 upregulation and DC differentiation. These results suggest that ZO-1 is differentially expressed while monocytes differentiate into DCs in the presence of 27OHChol via pathways in which distinct signaling molecules are involved.

Real-time imaging of inflammation and its resolution: It's apparent because it's transparent

The ability to directly observe leukocyte behavior in vivo has dramatically expanded our understanding of the immune system. Zebrafish are particularly amenable to the high-resolution imaging of leukocytes during both homeostasis and inflammation. Due to its natural transparency, intravital imaging in zebrafish does not require any surgical manipulation. As a result, zebrafish are particularly well-suited for the long-term imaging required to observe the temporal and spatial events during the onset and resolution of inflammation. Here, we review major insights about neutrophil and macrophage function gained from real-time imaging of zebrafish. We discuss neutrophil reverse migration, the process whereby neutrophils leave sites of tissue damage and resolve local inflammation. Further, we discuss the current tools available for investigating immune function in zebrafish and how future studies that simultaneously image multiple leukocyte subsets can be used to further dissect mechanisms that regulate both the onset and resolution of inflammation.

A multiscale cell-based model of tumor growth for chemotherapy assessment and tumor-targeted therapy through a 3D computational approach

OBJECTIVES

Computational modeling of biological systems is a powerful tool to clarify diverse processes contributing to cancer. The aim is to clarify the complex biochemical and mechanical interactions between cells, the relevance of intracellular signaling pathways in tumor progression and related events to the cancer treatments, which are largely ignored in previous studies.

MATERIALS AND METHODS

A three-dimensional multiscale cell-based model is developed, covering multiple time and spatial scales, including intracellular, cellular, and extracellular processes. The model generates a realistic representation of the processes involved from an implementation of the signaling transduction network.

RESULTS

Considering a benign tumor development, results are in good agreement with the experimental ones, which identify three different phases in tumor growth. Simulating tumor vascular growth, results predict a highly vascularized tumor morphology in a lobulated form, a consequence of cells' motile behavior. A novel systematic study of chemotherapy intervention, in combination with targeted therapy, is presented to address the capability of the model to evaluate typical clinical protocols. The model also performs a dose comparison study in order to optimize treatment efficacy and surveys the effect of chemotherapy initiation delays and different regimens.

CONCLUSIONS

Results not only provide detailed insights into tumor progression, but also support suggestions for clinical implementation. This is a major step toward the goal of predicting the effects of not only traditional chemotherapy but also tumor-targeted therapies.

Multiparametric and accurate functional analysis of genetic sequence variants using CRISPR-Select

Determining the functional role of thousands of genetic sequence variants (mutations) associated with genetic diseases is a major challenge. Here we present clustered regularly interspaced short palindromic repeat (CRISPR)-Select^TIME, CRISPR-Select^SPACE and CRISPR-Select^STATE, a set of flexible knock-in assays that introduce a genetic variant in a cell population and track its absolute frequencies relative to an internal, neutral control mutation as a function of time, space or a cell state measurable by flow cytometry. Phenotypically, CRISPR-Select can thereby determine, for example, pathogenicity, drug responsiveness/resistance or in vivo tumor promotion by a specific variant. Mechanistically, CRISPR-Select can dissect how the variant elicits the phenotype by causally linking the variant to motility/invasiveness or any cell state or biochemical process with a flow cytometry marker. The method is applicable to organoids, nontransformed or cancer cell lines. It is accurate, quantitative, fast and simple and works in single-well or 96-well higher throughput format. CRISPR-Select provides a versatile functional variant assay for research, diagnostics and drug development for genetic disorders.

Extracellular Signalling Modulates Scar/WAVE Complex Activity through Abi Phosphorylation

The lamellipodia and pseudopodia of migrating cells are produced and maintained by the Scar/WAVE complex. Thus, actin-based cell migration is largely controlled through regulation of Scar/WAVE. Here, we report that the Abi subunit-but not Scar-is phosphorylated in response to extracellular signalling in Dictyostelium cells. Like Scar, Abi is phosphorylated after the complex has been activated, implying that Abi phosphorylation modulates pseudopodia, rather than causing new ones to be made. Consistent with this, Scar complex mutants that cannot bind Rac are also not phosphorylated. Several environmental cues also affect Abi phosphorylation-cell-substrate adhesion promotes it and increased extracellular osmolarity diminishes it. Both unphosphorylatable and phosphomimetic Abi efficiently rescue the chemotaxis of Abi KO cells and pseudopodia formation, confirming that Abi phosphorylation is not required for activation or inactivation of the Scar/WAVE complex. However, pseudopodia and Scar patches in the cells with unphosphorylatable Abi protrude for longer, altering pseudopod dynamics and cell speed. Dictyostelium, in which Scar and Abi are both unphosphorylatable, can still form pseudopods, but migrate substantially faster. We conclude that extracellular signals and environmental responses modulate cell migration by tuning the behaviour of the Scar/WAVE complex after it has been activated.

Lipids in Pathophysiology and Development of the Membrane Lipid Therapy: New Bioactive Lipids

Membranes are mainly composed of a lipid bilayer and proteins, constituting a checkpoint for the entry and passage of signals and other molecules. Their composition can be modulated by diet, pathophysiological processes, and nutritional/pharmaceutical interventions. In addition to their use as an energy source, lipids have important structural and functional roles, e.g., fatty acyl moieties in phospholipids have distinct impacts on human health depending on their saturation, carbon length, and isometry. These and other membrane lipids have quite specific effects on the lipid bilayer structure, which regulates the interaction with signaling proteins. Alterations to lipids have been associated with important diseases, and, consequently, normalization of these alterations or regulatory interventions that control membrane lipid composition have therapeutic potential. This approach, termed membrane lipid therapy or membrane lipid replacement, has emerged as a novel technology platform for nutraceutical interventions and drug discovery. Several clinical trials and therapeutic products have validated this technology based on the understanding of membrane structure and function. The present review analyzes the molecular basis of this innovative approach, describing how membrane lipid composition and structure affects protein-lipid interactions, cell signaling, disease, and therapy (e.g., fatigue and cardiovascular, neurodegenerative, tumor, infectious diseases).

The Importance of Being PI3K in the RAS Signaling Network

Ras proteins are essential mediators of a multitude of cellular processes, and its deregulation is frequently associated with cancer appearance, progression, and metastasis. Ras-driven cancers are usually aggressive and difficult to treat. Although the recent Food and Drug Administration (FDA) approval of the first Ras G12C inhibitor is an important milestone, only a small percentage of patients will benefit from it. A better understanding of the context in which Ras operates in different tumor types and the outcomes mediated by each effector pathway may help to identify additional strategies and targets to treat Ras-driven tumors. Evidence emerging in recent years suggests that both oncogenic Ras signaling in tumor cells and non-oncogenic Ras signaling in stromal cells play an essential role in cancer. PI3K is one of the main Ras effectors, regulating important cellular processes such as cell viability or resistance to therapy or angiogenesis upon oncogenic Ras activation. In this review, we will summarize recent advances in the understanding of Ras-dependent activation of PI3K both in physiological conditions and cancer, with a focus on how this signaling pathway contributes to the formation of a tumor stroma that promotes tumor cell proliferation, migration, and spread.

Histatin 1 enhanced the speed and quality of wound healing through regulating the behaviour of fibroblast

Objectives

Histatin 1(Hst 1) has been proved to promote wound healing. However, there was no specific study on the regulation made by Hst 1 of fibroblasts in the process of wound healing. This research comprehensively studied the regulation of Hst 1 on the function of fibroblasts in the process of wound healing and preliminary mechanism about it.

Materials and methods

The full‐thickness skin wound model was made on the back of C57/BL6 mice. The wound healing, collagen deposition and fibroblast distribution were detected on days 3, 5 and 7 after injury. Fibroblast was cultured in vitro and stimulated with Hst 1, and then, their biological characteristics and functions were detected.

Results

Histatin 1 can effectively promote wound healing, improve collagen deposition during and after healing and increase the number and function of fibroblasts. After healing, the mechanical properties of the skin also improved. In vitro, the migration ability of fibroblasts stimulated by Hst 1 was significantly improved, and the fibroblasts transformed more into myofibroblasts, which improved the function of contraction and collagen secretion. In fibroblasts, mTOR signalling pathway can be activated by Hst 1.

Conclusions

Histatin 1 can accelerate wound healing and improve the mechanical properties of healed skin by promoting the function of fibroblasts. The intermolecular mechanisms need to be further studied, and this study provides a direction about mTOR signalling pathway.

Dysregulation of PI3K/Akt/PTEN Pathway in Canine Mammary Tumor

The PI3K/Akt/PTEN axis is one of the most important signaling pathways in tumorigenesis. Recently, mutation of PIK3CA has been highlighted due to the similarities of mutational hotspots in both dogs and humans. PIK3CA H1047R (c.3140A > G) has been discovered as the most common mutational hot spot in canine mammary tumor in recent studies, while the feature of PIK3CA-mutated canine mammary tumor is obscure.

METHODS

A total of 83 mammary samples classified as normal (n = 13), adenoma (n = 25), low-grade carcinoma (n = 21), and high-grade carcinoma (n = 24) were included in this study. Genomic DNA from each sample was extracted, amplified by conventional PCR, and analyzed through Sanger sequencing. Analysis for the expression of PIK3CA, Akt, p-Akt, and PTEN was performed by immunohistochemistry, and of Akt2 by RNA in situ hybridization.

RESULTS

PIK3CA H1047R mutation was detected in 14.3% (10/70) of tumor samples. Dysregulation of p-Akt, Akt2, and PTEN was observed in mammary tumor samples, but only PTEN dysregulation was associated with PIK3CA H1047R mutation.

CONCLUSIONS

The present study showed that dysregulation of components in the PI3K/Akt/PTEN pathway is a feature of canine mammary tumors, but this dysregulation is not directly correlated to the PIK3CA H1047R mutation except for PTEN expression.

Mechanism of WASP and WAVE family proteins in the progression of prostate cancer

Prostate cancer (PCa) is the second most commonly diagnosed and third lethal cause of death from cancer in men worldwide. Despite the availability of vast treatment procedures, still the high occurrence of invasion and metastasis of PCa are reported in cancer patients. The WASP (Wiskott-Aldrich syndrome protein) and WAVE (WASP family verprolin homologous protein) family of proteins are actin cytoskeleton regulatory proteins, reported to enhance cancer cell invasion and migration in prostate cancer. Hence, this review sheds light on the studies that explored the potential role of WASP and WAVE family of proteins in invasion and metastasis of prostate cancer. The research articles explored for the completion of this review were mostly from PubMed and Google Scholar by using the appropriate keywords for indexing. The conserved function of WASP and WAVE protein family is to receive the upstream signals from the Rho GTPase family and transmit them to activate the Arp2/3 complex that leads to rapid actin polymerization at leading edge of cells, which is crucial for PCa metastasis. Therefore, targeting these proteins could reflect a very interesting therapeutic opportunity to combat prostate cancer.

The Long-Term DEHP Exposure Confers Multidrug Resistance of Triple-Negative Breast Cancer Cells through ABC Transporters and Intracellular ROS

The characteristics of phthalates had been thought to be similar to endocrine disruptors, which increases cancer risk. The role of phthalates in acquired drug resistance remains unclear. In this study, we investigated the effect of di-(2-ethylhexyl) phthalate (DEHP) on acquired drug resistance in breast cancer. MCF7 and MDA-MB-231 breast cancer cells were exposed to long-term physiological concentration of DEHP for more than three months. Long-exposure DEHP permanently attenuated the anti-proliferative effect of doxorubicin with estrogen receptor-independent activity even after withdrawal of DEHP. Long term DEHP exposure significantly reduced ROS (O2-) level in MDA-MB-231 cells while increased in MCF7 cells. ATP-binding cassette (ABC) transporters possess a widely recognized mechanism of drug resistance and are considered a target for drug therapy. Upregulation of ABC family proteins, ABCB-1 and ABCC-1 observed in DEHP-exposed clones compared to doxorubicin-resistant (DoxR) and parental MDA-MB-231 cells. A viability assay showed enhanced multidrug resistance in DEHP-exposed clones against Dox, topotecan, and irinotecan. Inhibition of ABC transporters with tariquidar, enhanced drug cytotoxicity through increased drug accumulation reversing acquired multidrug resistance in MDA-MB-231 breast cancer cells. Tariquidar enhanced Dox cytotoxicity by increasing intracellular ROS production leading to caspase-3 mediated apoptosis. Activation of PI3K/Akt signaling enhanced proliferation and growth of DEHP-exposed MDA-MB-231 cells. Overall, long-term DEHP exposure resulted in acquired multidrug resistance by upregulating ABCB-1 and ABCC1; apart from proliferation PI3K/Akt may be responsible for acquired drug resistance through ABC transporter upregulation. Targeting ABCB1 and ABCC1 with tariquidar may be a promising strategy for reversing the acquired multidrug resistance of triple-negative breast cancer cells.

Toll receptors remodel epithelia by directing planar-polarized Src and PI3K activity

Toll-like receptors are essential for animal development and survival, with conserved roles in innate immunity, tissue patterning, and cell behavior. The mechanisms by which Toll receptors signal to the nucleus are well characterized, but how Toll receptors generate rapid, localized signals at the cell membrane to produce acute changes in cell polarity and behavior is not known. We show that Drosophila Toll receptors direct epithelial convergent extension by inducing planar-polarized patterns of Src and PI3-kinase (PI3K) activity. Toll receptors target Src activity to specific sites at the membrane, and Src recruits PI3K to the Toll-2 complex through tyrosine phosphorylation of the Toll-2 cytoplasmic domain. Reducing Src or PI3K activity disrupts planar-polarized myosin assembly, cell intercalation, and convergent extension, whereas constitutive Src activity promotes ectopic PI3K and myosin cortical localization. These results demonstrate that Toll receptors direct cell polarity and behavior by locally mobilizing Src and PI3K activity.

SAA1/TLR2 axis directs chemotactic migration of hepatic stellate cells responding to injury

Hepatic stellate cells (HSCs) are crucial for liver injury repair and cirrhosis. However, the mechanism of chemotactic recruitment of HSCs into injury loci is still largely unknown. Here, we demonstrate that serum amyloid A1 (SAA1) acts as a chemokine recruiting HSCs toward injury loci signaling via TLR2, a finding proven by gene manipulation studies in cell and mice models. The mechanistic investigations revealed that SAA1/TLR2 axis stimulates the Rac GTPases through PI3K-dependent pathways and induces phosphorylation of MLC (pSer19). Genetic deletion of TLR2 and pharmacological inhibition of PI3K diminished the phosphorylation of MLCpSer19 and migration of HSCs. In brief, SAA1 serves as a hepatic endogenous chemokine for the TLR2 receptor on HSCs, thereby initiating PI3K-dependent signaling and its effector, Rac GTPases, which consequently regulates actin filament remodeling and cell directional migration. Our findings provide novel targets for anti-fibrosis drug development.

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SAA1 serves as a chemokine to guide migration of HSCs toward injury locus

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TLR2 acts as a functional receptor for SAA1 in HSCs

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SAA1/TLR2 axis-mediated migration of HSCs operates through PI3K/Rac1 signaling

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SAA1/TLR2 axis provides a link for the cross talk between hepatocytes and HSCs

Regulation of PTEN translation by PI3K signaling maintains pathway homeostasis

The PI3K pathway regulates cell metabolism, proliferation, and migration, and its dysregulation is common in cancer. We now show that both physiologic and oncogenic activation of PI3K signaling increase the expression of its negative regulator PTEN. This limits the duration of the signal and output of the pathway. Physiologic and pharmacologic inhibition of the pathway reduces PTEN and contributes to the rebound in pathway activity in tumors treated with PI3K inhibitors and limits their efficacy. Regulation of PTEN is due to mTOR/4E-BP1-dependent control of its translation and is lost when 4E-BP1 is deleted. Translational regulation of PTEN is therefore a major homeostatic regulator of physiologic PI3K signaling and plays a role in reducing the pathway activation by oncogenic PIK3CA mutants and the antitumor activity of PI3K pathway inhibitors. However, pathway output is hyperactivated in tumor cells with coexistent PI3K mutation and loss of PTEN function.

Distinct epithelial-to-mesenchymal transitions induced by PIK3CA H1047R and PIK3CB

The most common PIK3CA mutation, producing the H1047R mutant of p110α, arises in myriad malignancies and is typically observed in low-grade breast tumours. In contrast, amplification is observed for wild-type PIK3CB, encoding p110β, and occurs at low frequency but in aggressive, high-grade metastatic tumours. We hypothesized that mutant p110α^H1047R and wild-type p110β give rise to distinct transformed phenotypes. We show that p110α^H1047R and wild-type p110β, but not wild-type p110α, transform MCF-10A cells and constitutively stimulate phosphoinositide 3-kinase (PI3K)-AKT pathway signalling. However, their resultant morphological transformed phenotypes are distinct. p110α^H1047R induced an epithelial-to-mesenchymal transition (EMT) commensurate with SNAIL (also known as SNAI1) induction and loss of E-cadherin. Upon p110β expression, however, E-cadherin expression was maintained despite cells readily delaminating from epithelial sheets. Distinct from the prominent filopodia in p110α^H1047R-expressing cells, p110β induced formation of lamellipodia, and these cells migrated with significantly greater velocity and decreased directionality. p110β-induced phenotypic alterations were accompanied by hyperactivation of RAC1; the dependency of transformation of p110β-binding to Rac1 revealed using a Rac1-binding mutant of p110β. Thus, PIK3CB amplification induces a transformed phenotype that is dependent upon a p110β-Rac1 signalling loop and is distinct from the transformed phenotype induced by p110α^H1047R.

CD2AP links actin to PI3 kinase activity to extend epithelial cell height and constrain cell area

Epithelial cells are categorized as cuboidal versus squamous based on the height of the lateral membrane. Wang and Brieher show that CD2AP links PI3K activity to actin assembly to extend the height of the lateral membrane.

Maintaining the correct ratio of apical, basal, and lateral membrane domains is important for epithelial physiology. Here, we show that CD2AP is a critical determinant of epithelial membrane proportions. Depletion of CD2AP or phosphoinositide 3-kinase (PI3K) inhibition results in loss of F-actin and expansion of apical–basal domains, which comes at the expense of lateral membrane height in MDCK cells. We demonstrate that the SH3 domains of CD2AP bind to PI3K and are necessary for PI3K activity along lateral membranes and constraining cell area. Tethering the SH3 domains of CD2AP or p110γ to the membrane is sufficient to rescue CD2AP-knockdown phenotypes. CD2AP and PI3K are both upstream and downstream of actin polymerization. Since CD2AP binds to both actin filaments and PI3K, CD2AP might bridge actin assembly to PI3K activation to form a positive feedback loop to support lateral membrane extension. Our results provide insight into the squamous to cuboidal to columnar epithelial transitions seen in complex epithelial tissues in vivo.

Stochastic Methods for Inferring States of Cell Migration

Cell migration refers to the ability of cells to translocate across a substrate or through a matrix. To achieve net movement requires spatiotemporal regulation of the actin cytoskeleton. Computational approaches are necessary to identify and quantify the regulatory mechanisms that generate directed cell movement. To address this need, we developed computational tools, based on stochastic modeling, to analyze time series data for the position of randomly migrating cells. Our approach allows parameters that characterize cell movement to be efficiently estimated from cell track data. We applied our methods to analyze the random migration of Mouse Embryonic Fibroblasts (MEFS) and HeLa cells. Our analysis revealed that MEFs exist in two distinct states of migration characterized by differences in cell speed and persistence, whereas HeLa cells only exhibit a single state. Further analysis revealed that the Rho-family GTPase RhoG plays a role in determining the properties of the two migratory states of MEFs. An important feature of our computational approach is that it provides a method for predicting the current migration state of an individual cell from time series data. Finally, we applied our computational methods to HeLa cells expressing a Rac1 biosensor. The Rac1 biosensor is known to perturb movement when expressed at overly high concentrations; at these expression levels the HeLa cells showed two migratory states, which correlated with differences in the spatial distribution of active Rac1.

Blueberry Counteracts BV-2 Microglia Morphological and Functional Switch after LPS Challenge

Microglia, the innate immune cells of the CNS, respond to brain injury by activating and modifying their morphology. Our study arises from the great interest that has been focused on blueberry (BB) for the antioxidant and pharmacological properties displayed by its components. We analyzed the influence of hydroalcoholic BB extract in resting or lipopolysaccharide (LPS)-stimulated microglia BV-2 cells. BB exerted a protective effect against LPS-induced cytotoxicity, as indicated by cell viability. BB was also able to influence the actin cytoskeleton organization, to recover the control phenotype after LPS insult, and also to reduce LPS-driven migration. We evaluated the activity of Rho and Rac1 GTPases, which regulate both actin cytoskeletal organization and migratory capacity. LPS caused an increase in Rac1 activity, which was counteracted by BB extract. Furthermore, we demonstrated that, in the presence of BB, mRNA expression of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α decreased, as did the immunofluorescence signal of iNOS, whereas that of Arg-1 was increased. Taken together, our results show that, during the inflammatory response, BB extract shifts the M1 polarization towards the M2 phenotype through an actin cytoskeletal rearrangement. Based on that, we might consider BB as a nutraceutical with anti-inflammatory activities.

Integrin crosstalk allows CD4+ T lymphocytes to continue migrating in the upstream direction after flow

In order to perform critical immune functions at sites of inflammation, circulatory T lymphocytes must be able to arrest, adhere, migrate and transmigrate on the endothelial surface. This progression of steps is coordinated by cellular adhesion molecules (CAMs), chemokines, and selectins presented on the endothelium. Two important interactions are between Lymphocyte Function-associated Antigen-1 (LFA-1) and Intracellular Adhesion Molecule-1 (ICAM-1) and also between Very Late Antigen-4 (VLA-4) and Vascular Cell Adhesion Molecule-1 (VCAM-1). Recent studies have shown that T lymphocytes and other cell types can migrate upstream (against the direction) of flow through the binding of LFA-1 to ICAM-1. Since upstream migration of T cells depends on a specific adhesive pathway, we hypothesized that mechanotransduction is critical to migration, and that signals might allow T-cells to remember their direction of migration after the flow is terminated. Cells on ICAM-1 surfaces migrate against the shear flow, but the upstream migration reverts to random migration after the flow is stopped. Cells on VCAM-1 migrate with the direction of flow. However, on surfaces that combine ICAM-1 and VCAM-1, cells crawl upstream at a shear rate of 800 s-1 and continue migrating in the upstream direction for at least 30 minutes after the flow is terminated-we call this 'migrational memory'. Post-flow upstream migration on VCAM-1/ICAM-1 surfaces is reversed upon the inhibition of PI3K, but conserved with cdc42 and Arp2/3 inhibitors. Using an antibody against VLA-4, we can block migrational memory on VCAM-1/ICAM-1 surfaces. Using a soluble ligand for VLA-4 (sVCAM-1), we can promote migrational memory on ICAM-1 surfaces. These results indicate that, while upstream migration under flow requires LFA-1 binding to immobilized ICAM-1, signaling from VLA-4 and PI3K activity is required for the migrational memory of CD4+ T cells. These results indicate that crosstalk between integrins potentiates the signal of upstream migration.

Keratocyte biology

The study of corneal stromal keratocytes is motivated by its strong association with corneal health and visual function. They play a dominant role in the maintenance of corneal homeostasis and transparency through the production of collagens, proteoglycans and corneal crystallins. Trauma-induced apoptosis of keratocytes and replacement by fibroblasts and myofibroblasts disrupt the stromal matrix organization, resulting in corneal haze formation and vision loss. It is, therefore, important to understand the biology and behaviours of keratocytes and the associated stromal cell types (like fibroblasts, myofibroblasts, stromal stem cells) in wound healing, corneal pathologies (including keratoconus, keratitis, endothelial disorders) as well as different ophthalmic situations (such as collagen crosslinking/photodynamic treatment, keratoplasty and refractive surgery, and topical medications). The recent development of ex vivo propagation of keratocytes and stromal stem cells, and their translational applications, either via stromal injection or incorporated in bioscaffold, have been shown to restore the corneal transparency and regenerate native stromal tissue in animal models of corneal haze and other disorders.

Early pathological signs in young dysf-/- mice are improved by halofuginone

Dysferlinopathies are a non-lethal group of late-onset muscular dystrophies. Here, we evaluated the fusion ability of primary myoblasts from young dysf^-/- mice and the muscle histopathology prior to, and during early stages of disease onset. The ability of primary myoblasts of 5-week-old dysf^-/- mice to form large myotubes was delayed compared to their wild-type counterparts, as evaluated by scanning electron microscopy. However, their fusion activity, as reflected by the presence of actin filaments connecting several cells, was enhanced by the antifibrotic drug halofuginone. Early dystrophic signs were already apparent in 4-week-old dysf^-/- mice; their collagen level was double that in wild-type mice and continued to rise until 5 months of age. Continuous treatment with halofuginone from 4 weeks to 5 months of age reduced muscle fibrosis in a phosphorylated-Smad3 inhibition-related manner. Halofuginone also enhanced myofiber hypertrophy, reduced the percentage of centrally nucleated myofibers, and increased muscle performance. Together, the data suggest an inhibitory effect of halofuginone on the muscle histopathology at very early stages of dysferlinopathy, and enhancement of muscle performance. These results offer new opportunities for early pharmaceutical treatment in dysferlinopathies with favorable outcomes at later stages of life.

Truncated ASPP2 Drives Initiation and Progression of Invasive Lobular Carcinoma via Distinct Mechanisms

Invasive lobular carcinoma (ILC) accounts for 8%-14% of all breast cancer cases. The main hallmark of ILCs is the functional loss of the cell-cell adhesion protein E-cadherin. Nonetheless, loss of E-cadherin alone does not predispose mice to mammary tumor development, indicating that additional perturbations are required for ILC formation. Previously, we identified an N-terminal truncation variant of ASPP2 (t-ASPP2) as a driver of ILC in mice with mammary-specific loss of E-cadherin. Here we showed that expression of t-ASPP2 induced actomyosin relaxation, enabling adhesion and survival of E-cadherin-deficient murine mammary epithelial cells on stiff matrices like fibrillar collagen. The induction of actomyosin relaxation by t-ASPP2 was dependent on its interaction with protein phosphatase 1, but not on t-ASPP2-induced YAP activation. Truncated ASPP2 collaborated with both E-cadherin loss and PI3K pathway activation via PTEN loss in ILC development. t-ASPP2-induced actomyosin relaxation was required for ILC initiation, but not progression. Conversely, YAP activation induced by t-ASPP2 contributed to tumor growth and progression while being dispensable for tumor initiation. Together, these findings highlight two distinct mechanisms through which t-ASPP2 promotes ILC initiation and progression. SIGNIFICANCE: Truncated ASPP2 cooperates with E-cadherin and PTEN loss to drive breast cancer initiation and progression via two distinct mechanisms. ASPP2-induced actomyosin relaxation drives tumor initiation, while ASPP2-mediated YAP activation enhances tumor progression.

Cardioprotective effects of genetically engineered cardiac stem cells by spheroid formation on ischemic cardiomyocytes

BACKGROUND

Sca-1+ cardiac stem cells and their limited proliferative potential were major limiting factors for use in various studies.

METHODS

Therefore, the effects of sphere genetically engineered cardiac stem cells (S-GECS) inserted with telomerase reverse transcriptase (TERT) were investigated to examine cardiomyocyte survival under hypoxic conditions. GECS was obtained from hTERT-immortalized Sca-1+ cardiac stem cell (CSC) lines, and S-GECS were generated using poly-HEMA.

RESULTS

The optimal conditions for S-GECS was determined to be 1052 GECS cells/mm² and a 48 h culture period to produce spheroids. Compared to adherent-GECS (A-GECS) and S-GECS showed significantly higher mRNA expression of SDF-1α and CXCR4. S-GECS conditioned medium (CM) significantly reduced the proportion of early and late apoptotic cardiomyoblasts during CoCl₂-induced hypoxic injury; however, gene silencing via CXCR4 siRNA deteriorated the protective effects of S-GECS against hypoxic injury. As downstream pathways of SDF-1α/CXCR4, the Erk and Akt signaling pathways were stimulated in the presence of S-GECS CM. S-GECS transplantation into a rat acute myocardial infarction model improved cardiac function and reduced the fibrotic area. These cardioprotective effects were confirmed to be related with the SDF-1α/CXCR4 pathway.

CONCLUSIONS

Our findings suggest that paracrine factors secreted from transplanted cells may protect host cardiomyoblasts in the infarcted myocardium, contributing to beneficial left ventricle (LV) remodeling after acute myocardial infarction (AMI).

Microtubule-Based Control of Motor-Clutch System Mechanics in Glioma Cell Migration

Microtubule-targeting agents (MTAs) are widely used chemotherapy drugs capable of disrupting microtubule-dependent cellular functions, such as division and migration. We show that two clinically approved MTAs, paclitaxel and vinblastine, each suppress stiffness-sensitive migration and polarization characteristic of human glioma cells on compliant hydrogels. MTAs influence microtubule dynamics and cell traction forces by nearly opposite mechanisms, the latter of which can be explained by a combination of changes in myosin motor and adhesion clutch number. Our results support a microtubule-dependent signaling-based model for controlling traction forces through a motor-clutch mechanism, rather than microtubules directly relieving tension within F-actin and adhesions. Computational simulations of cell migration suggest that increasing protrusion number also impairs stiffness-sensitive migration, consistent with experimental MTA effects. These results provide a theoretical basis for the role of microtubules and mechanisms of MTAs in controlling cell migration.

Prahl et al. examine the mechanisms by which microtubule-targeting drugs inhibit glioma cell migration. They find that dynamic microtubules regulate actin-based protrusion dynamics that facilitate cell polarity and migration. Changes in net microtubule assembly alter cell traction forces via signaling-based regulation of a motor-clutch system.

Rebalancing of actomyosin contractility enables mammary tumor formation upon loss of E-cadherin

E-cadherin (CDH1) is a master regulator of epithelial cell adherence junctions and a well-established tumor suppressor in Invasive Lobular Carcinoma (ILC). Intriguingly, somatic inactivation of E-cadherin alone in mouse mammary epithelial cells (MMECs) is insufficient to induce tumor formation. Here we show that E-cadherin loss induces extrusion of luminal MMECs to the basal lamina. Remarkably, E-cadherin-deficient MMECs can breach the basal lamina but do not disseminate into the surrounding fat pad. Basal lamina components laminin and collagen IV supported adhesion and survival of E-cadherin-deficient MMECs while collagen I, the principle component of the mammary stromal micro-environment did not. We uncovered that relaxation of actomyosin contractility mediates adhesion and survival of E-cadherin-deficient MMECs on collagen I, thereby allowing ILC development. Together, these findings unmask the direct consequences of E-cadherin inactivation in the mammary gland and identify aberrant actomyosin contractility as a critical barrier to ILC formation.

Emerging roles of aerobic glycolysis in breast cancer

Altered aerobic glycolysis is a well-recognized characteristic of cancer cell energy metabolism, known as the Warburg effect. Even in the presence of abundant oxygen, a majority of tumor cells produce substantial amounts of energy through a high glycolytic metabolism, and breast cancer (BC) is no exception. Breast cancer continues to be the second leading cause of cancer-associated mortality in women worldwide. However, the precise role of aerobic glycolysis in the development of BC remains elusive. Therefore, the present review attempts to address the implication of key enzymes of the aerobic glycolytic pathway including hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), glucose transporters (GLUTs), together with related signaling pathways including protein kinase B(PI3K/AKT), mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) and transcription factors (c-myc, p53 and HIF-1) in the research of BC. Thus, the review of aerobic glycolysis in BC may evoke novel ideas for the BC treatment.

The matrix environmental and cell mechanical properties regulate cell migration and contribute to the invasive phenotype of cancer cells

The minimal structural unit of a solid tumor is a single cell or a cellular compartment such as the nucleus. A closer look inside the cells reveals that there are functional compartments or even structural domains determining the overall properties of a cell such as the mechanical phenotype. The mechanical interaction of these living cells leads to the complex organization such as compartments, tissues and organs of organisms including mammals. In contrast to passive non-living materials, living cells actively respond to the mechanical perturbations occurring in their microenvironment during diseases such as fibrosis and cancer. The transformation of single cancer cells in highly aggressive and hence malignant cancer cells during malignant cancer progression encompasses the basement membrane crossing, the invasion of connective tissue, the stroma microenvironments and transbarrier migration, which all require the immediate interaction of the aggressive and invasive cancer cells with the surrounding extracellular matrix environment including normal embedded neighboring cells. All these steps of the metastatic pathway seem to involve mechanical interactions between cancer cells and their microenvironment. The pathology of cancer due to a broad heterogeneity of cancer types is still not fully understood. Hence it is necessary to reveal the signaling pathways such as mechanotransduction pathways that seem to be commonly involved in the development and establishment of the metastatic and mechanical phenotype in several carcinoma cells. We still do not know whether there exist distinct metastatic genes regulating the progression of tumors. These metastatic genes may then be activated either during the progression of cancer by themselves on their migration path or in earlier stages of oncogenesis through activated oncogenes or inactivated tumor suppressor genes, both of which promote the metastatic phenotype. In more detail, the adhesion of cancer cells to their surrounding stroma induces the generation of intracellular contraction forces that deform their microenvironments by alignment of fibers. The amplitude of these forces can adapt to the mechanical properties of the microenvironment. Moreover, the adhesion strength of cancer cells seems to determine whether a cancer cell is able to migrate through connective tissue or across barriers such as the basement membrane or endothelial cell linings of blood or lymph vessels in order to metastasize. In turn, exposure of adherent cancer cells to physical forces, such as shear flow in vessels or compression forces around tumors, reinforces cell adhesion, regulates cell contractility and restructures the ordering of the local stroma matrix that leads subsequently to secretion of crosslinking proteins or matrix degrading enzymes. Hence invasive cancer cells alter the mechanical properties of their microenvironment. From a mechanobiological point-of-view, the recognized physical signals are transduced into biochemical signaling events that guide cellular responses such as cancer progression after the malignant transition of cancer cells from an epithelial and non-motile phenotype to a mesenchymal and motile (invasive) phenotype providing cellular motility. This transition can also be described as the physical attempt to relate this cancer cell transitional behavior to a T1 phase transition such as the jamming to unjamming transition. During the invasion of cancer cells, cell adaptation occurs to mechanical alterations of the local stroma, such as enhanced stroma upon fibrosis, and therefore we need to uncover underlying mechano-coupling and mechano-regulating functional processes that reinforce the invasion of cancer cells. Moreover, these mechanisms may also be responsible for the awakening of dormant residual cancer cells within the microenvironment. Physicists were initially tempted to consider the steps of the cancer metastasis cascade as single events caused by a single mechanical alteration of the overall properties of the cancer cell. However, this general and simple view has been challenged by the finding that several mechanical properties of cancer cells and their microenvironment influence each other and continuously contribute to tumor growth and cancer progression. In addition, basement membrane crossing, cell invasion and transbarrier migration during cancer progression is explained in physical terms by applying physical principles on living cells regardless of their complexity and individual differences of cancer types. As a novel approach, the impact of the individual microenvironment surrounding cancer cells is also included. Moreover, new theories and models are still needed to understand why certain cancers are malignant and aggressive, while others stay still benign. However, due to the broad variety of cancer types, there may be various pathways solely suitable for specific cancer types and distinct steps in the process of cancer progression. In this review, physical concepts and hypotheses of cancer initiation and progression including cancer cell basement membrane crossing, invasion and transbarrier migration are presented and discussed from a biophysical point-of-view. In addition, the crosstalk between cancer cells and a chronically altered microenvironment, such as fibrosis, is discussed including the basic physical concepts of fibrosis and the cellular responses to mechanical stress caused by the mechanically altered microenvironment. Here, is highlighted how biophysical approaches, both experimentally and theoretically, have an impact on classical hallmarks of cancer and fibrosis and how they contribute to the understanding of the regulation of cancer and its progression by sensing and responding to the physical environmental properties through mechanotransduction processes. Finally, this review discusses various physical models of cell migration such as blebbing, nuclear piston, protrusive force and unjamming transition migration modes and how they contribute to cancer progression. Moreover, these cellular migration modes are influenced by microenvironmental perturbances such as fibrosis that can induce mechanical alterations in cancer cells, which in turn may impact the environment. Hence, the classical hallmarks of cancer need to be refined by including biomechanical properties of cells, cell clusters and tissues and their microenvironment to understand mechano-regulatory processes within cancer cells and the entire organism.

Examining the feasibility of a "top-down" approach to enhancing the keratinocyte-implant adhesion

The adhesion of human epidermal keratinocytes to the implant surface is one of the most critical steps during the patient's recovery from implantation of transcutaneous prosthesis. To improve the success rate of transcutaneous prosthetic implants, we explored a new "top-down" approach to promoting this dynamic adhering process through modulation of upstream cell signaling pathways. To examine the feasibility of this novel approach, we first established an in vitro platform that is capable of providing a non-invasive, real-time, quantitative characterization of the keratinocyte-implant interaction. This platform is based on the dissipation monitoring function of the quartz crystal microbalance with dissipation monitoring (QCM-D) in conjunction with the open-module setup of the QCM-D. We then employed this platform to assess the effects of various pathways-specific modulators on the adhering process of keratinocytes. We demonstrated that this "top-down" approach is as effective in enhancing the adhesion of keratinocytes as the conventional "bottom-up" approach that relies on modifying the substrate surface with the adhesion protein such as fibronectin. We envision that this new "top-down" approach combined with the QCM-D-based in vitro platform will help facilitate the future development of new therapies for enhancing osseointegration and promoting wound healing.

The Volume-Regulated Anion Channel in Glioblastoma

Malignancy of glioblastoma multiforme (GBM), the most common and aggressive form of human brain tumor, strongly depends on its enhanced cell invasion and death evasion which make surgery and accompanying therapies highly ineffective. Several ion channels that regulate membrane potential, cytosolic Ca²⁺ concentration and cell volume in GBM cells play significant roles in sustaining these processes. Among them, the volume-regulated anion channel (VRAC), which mediates the swelling-activated chloride current (IClswell) and is highly expressed in GBM cells, arguably plays a major role. VRAC is primarily involved in reestablishing the original cell volume that may be lost under several physiopathological conditions, but also in sustaining the shape and cell volume changes needed for cell migration and proliferation. While experimentally VRAC is activated by exposing cells to hypotonic solutions that cause the increase of cell volume, in vivo it is thought to be controlled by several different stimuli and modulators. In this review we focus on our recent work showing that two conditions normally occurring in pathological GBM tissues, namely high serum levels and severe hypoxia, were both able to activate VRAC, and their activation was found to promote cell migration and resistance to cell death, both features enhancing GBM malignancy. Also, the fact that the signal transduction pathway leading to VRAC activation appears to involve GBM specific intracellular components, such as diacylglicerol kinase and phosphatidic acid, reportedly not involved in the activation of VRAC in healthy tissues, is a relevant finding. Based on these observations and the impact of VRAC in the physiopathology of GBM, targeting this channel or its intracellular regulators may represent an effective strategy to contrast this lethal tumor.