The effects of purslane consumption on lipid profile and C-reactive protein: A systematic review and dose-response meta-analysis.

Earlier investigations into the impact of purslane, Portulaca oleracea, on lipid profile and C-reactive protein (CRP) produced contradictory findings. The effect of purslane consumption on lipid profiles and CRP was assessed in this comprehensive review and meta-analysis. We conducted a thorough literature search in online databases, including PubMed, Scopus, the Cochrane library, and ISI Web of Science to find relevant randomized controlled trials up to June 2023. By incorporating 14 effect sizes from 13 RCTs, we were able to show that purslane consumption significantly decreases serum triglyceride (TG) (WMD: -16.72, 95% CI: -22.49, -10.96 mg/dL, p < .001), total cholesterol (TC) (WMD: -9.97, 95% CI: -19.86, -0.07 mg/dL, p = .048), and CRP (WMD: -1.22, 95% CI: -1.63, -0.80 mg/L, p < .001) levels in patients compared to the control group. In addition, purslane consumption significantly increases high-density lipoprotein (HDL-C) (WMD: 4.09, 95% CI: 1.77, 6.41 mg/dL, p = .001) levels. However, purslane consumption did not affect low-density lipoprotein (LDL-C) levels. According to a suggested optimal dosage, purslane consumption is considered to be safe up to 30 g/day. Purslane consumption can significantly improve cardiovascular health by improving lipid profile and inflammation status.

The effects of purslane consumption on glycemic control and oxidative stress: A systematic review and dose-response meta-analysis.

Purslane (Portulaca oleracea L.) is a herbal remedy with wide range of pharmaceutic properties. Although the beneficial effect of purslane on the treatment of Type 2 Diabetes Mellitus (T2DM) has been shown, there is an inconsistency among the results of previous studies. Therefore, this study is aimed at conducting a systematic review and meta-analysis on the effect of purslane on glycemic profile and oxidative stress markers. A systematic search was performed in the Scopus, Web of science, PubMed and the Cochrane Library to find articles related to the effect of the purslane on Malondialdehyde (MDA) and Total Antioxidant Capacity (TAC), Fasting Blood Sugar (FBS), Hemoglobin A1c (HbA1c), insulin resistance, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) up to September 2022. Among the 611 initial studies that were identified from searching electronic databases, 16 Randomized Clinical Trials (RCTs) involving 1122 participants (557 cases and 565 controls) were included for data analysis. The results of random-effects modeling demonstrated that purslane consumption significantly reduced FBS (p < .001), MDA (p < .001) and increased TAC (p < .001). However, purslane consumption did not affect HbA1c (p < .109), fasting insulin (p = .298) and HOMA-IR (p = .382). Meta-analyses were performed using both the random- and fixed-effects model where appropriate, and I 2 index was used to evaluate the heterogeneity. This meta-analysis study suggests that purslane has beneficial effects on oxidative stress markers and glycemic parameter. Therefore, it may be a promising adjuvant therapy in T2DM because of its benefits and negligible adverse effects.

Novel plasma exosome biomarkers for prostate cancer progression in co-morbid metabolic disease.

Comorbid Type 2 diabetes (T2D), a metabolic complication of obesity, associates with worse cancer outcomes for prostate, breast, head and neck, colorectal and several other solid tumors. However, the molecular mechanisms remain poorly understood. Emerging evidence shows that exosomes carry miRNAs in blood that encode the metabolic status of originating tissues and deliver their cargo to target tissues to modulate expression of critical genes. Exosomal communication potentially connects abnormal metabolism to cancer progression. Here, we hypothesized that T2D plasma exosomes induce epithelial-mesenchymal transition (EMT) and immune checkpoints in prostate cancer cells. We demonstrate that plasma exosomes from subjects with T2D induce EMT features in prostate cancer cells and upregulate the checkpoint genes CD274 and CD155. We demonstrate that specific exosomal miRNAs that are differentially abundant in plasma of T2D adults compared to nondiabetic controls (miR374a-5p, miR-93-5p and let-7b-3p) are delivered to cancer cells, thereby regulating critical target genes. We build on our previous reports showing BRD4 controls migration and dissemination of castration-resistant prostate cancer, and transcription of key EMT genes, to show that T2D exosomes require BRD4 to drive EMT and immune ligand expression. We validate our findings with gene set enrichment analysis of human prostate tumor tissue in TGCA genomic data. These results suggest novel, non-invasive approaches to evaluate and potentially block progression of prostate and other cancers in patients with comorbid T2D.

Adipocyte-derived exosomes may promote breast cancer progression in type 2 diabetes.

Obesity and metabolic diseases, such as insulin resistance and type 2 diabetes (T2D), are associated with metastatic breast cancer in postmenopausal women. Here, we investigated the critical cellular and molecular factors behind this link. We found that primary human adipocytes shed extracellular vesicles, specifically exosomes, that induced the expression of genes associated with epithelial-to-mesenchymal transition (EMT) and cancer stem­like cell (CSC) traits in cocultured breast cancer cell lines. Transcription of these genes was further increased in cells exposed to exosomes shed from T2D patient­derived adipocytes or insulin-resistant adipocytes and required the epigenetic reader proteins BRD2 and BRD4 in recipient cells. The thrombospondin family protein TSP5, which is associated with cancer, was more abundant in exosomes from T2D or insulin-resistant adipocytes and partially contributed to EMT in recipient cells. Bioinformatic analysis of breast cancer patient tissue showed that greater coexpression of COMP (which encodes TSP5) and BRD2 or BRD3 correlated with poorer prognosis, specifically decreased distant metastasis­free survival. Our findings reveal a mechanism of exosome-mediated cross-talk between metabolically abnormal adipocytes and breast cancer cells that may promote tumor aggressiveness in patients with T2D.

BRD4 regulates key transcription factors that drive epithelial-mesenchymal transition in castration-resistant prostate cancer.

BACKGROUND: Androgen deprivation therapies for the hormone-dependent stages of prostate cancer have become so effective that new forms of chemoresistant tumors are emerging in clinical practice, and require new targeted therapies in the metastatic setting. Yet there are important gaps in our understanding of the relevant transcriptional networks driving this process. Progression from localized to metastatic castration resistant prostate cancer (mCRPC) occurs as a result of accumulated resistance mechanisms that develop upon sustained androgen receptor (AR) suppression. Critical to this progression is the plastic nature by which prostate tumor cells transition from epithelial to mesenchymal states (EMT). METHODS: Here, using prostate cancer cell lines with different AR composition, we systematically manipulated somatic proteins of the Bromodomain and ExtraTerminal (BET) family (BRD2, BRD3, and BRD4) to determine which BET proteins influence EMT. We used the TCGA repository to correlate the expression of individual BET genes with key EMT genes and determined biochemical recurrence in 414 patients and progression free survival in 488 patients. RESULTS: We found that only BRD4-and not BRD2 or BRD3-regulates the expression of SNAI1 and SNAI2, and that the downregulation of these EMT transcription factors significantly increases E-cadherin expression. Furthermore, of the BET genes, only BRD4 correlates with survival outcomes in prostate cancer patients. Moreover, selective degradation of BRD4 protein with MZ1 ablates EMT (transcriptionally and morphologically) induced by TGFß signaling. CONCLUSIONS: Many relapsed/refractory tumors share a neuroendocrine transcriptional signature that had been relatively rare until highly successful antiandrogen drugs like abiraterone and enzalutamide came into widespread use. New therapeutic targets must therefore be developed. Our results identify key EMT genes regulated by BRD4, and offers a novel druggable target to treat mCRPC. BRD4-selective protein degraders offer a promising next generation approach to treat the emerging forms of chemoresistance in advanced prostate cancer.

Inhibition of Fatty Acid Synthase Upregulates Expression of CD36 to Sustain Proliferation of Colorectal Cancer Cells.

Fatty acid synthase, a key enzyme of de novo lipogenesis, is an attractive therapeutic target in cancer. The novel fatty acid synthase inhibitor, TVB-3664, shows anti-cancer activity in multiple cancers including colorectal cancer; however, it is unclear whether uptake of exogeneous fatty acids can compensate for the effect of fatty acid synthase inhibition. This study demonstrates that inhibition of fatty acid synthase selectively upregulates fatty acid translocase (CD36), a fatty acid transporter, in multiple colorectal cancer models including colorectal cancer cells with shRNA mediated knockdown of fatty acid synthase and genetically modified mouse tissues with heterozygous and homozygous deletion of fatty acid synthase. Furthermore, human colorectal cancer tissues treated with TVB-3664 show a significant and selective upregulation of CD36 mRNA. shRNA-mediated knockdown of CD36 and inhibition of CD36 via sulfosuccinimidyl oleate, a chemical inhibitor of CD36, decreased cell proliferation in vitro and reduced tumor growth in subcutaneous xenograft models. Isogenic cell populations established from patient derived xenografts and expressing high levels of CD36 show a significantly increased ability to grow tumors in vivo. The tumor-promoting effect of CD36 is associated with an increase in the levels of pAkt and survivin. Importantly, combinatorial treatment of primary and established colorectal cancer cells with TVB-3664 and sulfosuccinimidyl oleate shows a synergistic effect on cell proliferation. In summary, our study demonstrates that upregulation of CD36 expression is a potential compensatory mechanism for fatty acid synthase inhibition and that inhibition of CD36 can improve the efficacy of fatty acid synthase-targeted therapy.

Novel semi-automated algorithm for high-throughput quantification of adipocyte size in breast adipose tissue, with applications for breast cancer microenvironment.

The size distribution of adipocytes in fat tissue provides important information about metabolic status and overall health of patients. Histological measurements of biopsied adipose tissue can reveal cardiovascular and/or cancer risks, to complement typical prognosis parameters such as body mass index, hypertension or diabetes. Yet, current methods for adipocyte quantification are problematic and insufficient. Methods such as hand-tracing are tedious and time-consuming, ellipse approximation lacks precision, and fully automated methods have not proven reliable. A semi-automated method fills the gap in goal-directed computational algorithms, specifically for high-throughput adipocyte quantification. Here, we design and develop a tool, AdipoCyze, which incorporates a novel semi-automated tracing algorithm, along with benchmark methods, and use breast histological images from the Komen for the Cure Foundation to assess utility. Speed and precision of the new approach are superior to conventional methods and accuracy is comparable, suggesting a viable option to quantify adipocytes, while increasing user flexibility. This platform is the first to provide multiple methods of quantification in a single tool. Widespread laboratory and clinical use of this program may enhance productivity and performance, and yield insight into patient metabolism, which may help evaluate risks for breast cancer progression in patients with comorbidities of obesity. ABBREVIATIONS: BMI: body mass index.

BET protein targeting suppresses the PD-1/PD-L1 pathway in triple-negative breast cancer and elicits anti-tumor immune response.

Therapeutic strategies aiming to leverage anti-tumor immunity are being intensively investigated as they show promising results in cancer therapy. The PD-1/PD-L1 pathway constitutes an important target to restore functional anti-tumor immune response. Here, we report that BET protein inhibition suppresses PD-1/PD-L1 in triple-negative breast cancer. BET proteins control PD-1 expression in T cells, and PD-L1 in breast cancer cell models. BET protein targeting reduces T cell-derived interferon-γ production and signaling, thereby suppressing PD-L1 induction in breast cancer cells. Moreover, BET protein inhibition improves tumor cell-specific T cell cytotoxic function. Overall, we demonstrate that BET protein targeting represents a promising strategy to overcome tumor-reactive T cell exhaustion and improve anti-tumor immune responses, by reducing the PD-1/PD-L1 axis in triple-negative breast cancer.

De Novo Fatty Acid Synthesis-Driven Sphingolipid Metabolism Promotes Metastatic Potential of Colorectal Cancer.

Metastasis is the most common cause of death in colorectal cancer patients. Fatty acid synthase (FASN) and sphingosine kinase-1 and -2 (SPHK1 and 2) are overexpressed in many cancers, including colorectal cancer. However, the contribution of FASN-mediated upregulation of sphingolipid metabolism to colorectal cancer metastasis and the potential of these pathways as targets for therapeutic intervention remain unknown. This study determined that sphingosine kinases (SPHK) are overexpressed in colorectal cancer as compared with normal mucosa. FASN expression significantly correlated with SPHK2 expression in data sets from The Cancer Genome Atlas (TCGA) and a colorectal cancer tumor microarray. FASN, SPHK1, and SPHK2 colocalized within invadopodia of primary colorectal cancer cells. Moreover, FASN inhibition decreased SPHK2 expression and the levels of dihydrosphingosine 1-phosphate (DH-S1P) and sphingosine 1-phosphate (S1P) in colorectal cancer cells and tumor tissues. Inhibition of FASN using TVB-3664 and sphingolipid metabolism using FTY-720 significantly inhibited the ability of primary colorectal cancer cells to proliferate, migrate, form focal adhesions, and degrade gelatin. Inhibition of the FASN/SPHK/S1P axis was accompanied by decreased activation of p-MET, p-FAK, and p-PAX. S1P treatment rescued FASN-mediated inhibition of these proteins, suggesting that FASN promotes metastatic properties of colorectal cancer cells, in part, through an increased sphingolipid metabolism. These data demonstrate that upregulation of the FASN/SPHK/S1P axis promotes colorectal cancer progression by enhancing proliferation, adhesion, and migration. IMPLICATIONS: This study provides a strong rationale for further investigation of the interconnection of de novo lipogenesis and sphingolipid metabolism that could potentially lead to the identification of new therapeutic targets and strategies for colorectal cancer.

Cdk5-mediated phosphorylation regulates phosphatidylinositol 4-phosphate 5-kinase type I γ 90 activity and cell invasion.

Phosphatidylinositol 4-phosphate 5-kinase type I γ (PIPKIγ90) regulates cell migration, invasion, and metastasis. However, it is unknown how cellular signals regulate those processes. Here, we show that cyclin-dependent kinase 5 (Cdk5), a protein kinase that regulates cell migration and invasion, phosphorylates PIPKIγ90 at S453, and that Cdk5-mediated PIPKIγ90 phosphorylation is essential for cell invasion. Moreover, Cdk5-mediated phosphorylation down-regulates the activity of PIPKIγ90 and the secretion of fibronectin, an extracellular matrix protein that regulates cell migration and invasion. Furthermore, inhibition of PIPKIγ activity with the chemical inhibitor UNC3230 suppresses fibronectin secretion in a dose-dependent manner, whereas depletion of Cdk5 enhances fibronectin secretion. With total internal reflection fluorescence microscopy, we found that secreted fibronectin appears as round dots, which colocalize with Tks5 and CD9 but not with Zyxin. These data suggest that Cdk5-mediated PIPKIγ90 phosphorylation regulates cell invasion by controlling PIPKIγ90 activity and fibronectin secretion.-Li, L., Kolodziej, T., Jafari, N., Chen, J., Zhu, H., Rajfur, Z., Huang, C. Cdk5-mediated phosphorylation regulates phosphatidylinositol 4-phosphate 5-kinase type I γ 90 activity and cell invasion.

Cell Cycle Arrest and Apoptosis Induction of Phloroacetophenone Glycosides and Caffeoylquinic Acid Derivatives in Gastric Adenocarcinoma (AGS) Cells.

INTRODUCTION: In the present study, we analyzed anti-proliferative and apoptosis induction activity of five phenolic compounds: echisoside, pleoside, chlorogenic acid, 4,5-Di-O-caffeoylquinic acid, and cynarin on AGS (adenocarcinoma gastric) cell line. METHOD: These phenolic compounds were isolated from methanol extract of Dorema glabrum root. An MTT assay was conducted to evaluate the inhibitory effect on cancer cells. EB/AO staining was done to assess the mode of cell death and morphological changes of the cells' nuclei. Cell cycle distribution of the cells was analyzed by flow cytometry, and for further confirmation of the pathway, mRNA levels of apoptosis cascade players were quantified by qRT-PCR. RESULT: We found that echisoside, pleoside, chlorogenic acid, 4,5-Di-O-caffeoylquinic acid, and cynarin inhibited the proliferation of AGS cancer cells in vitro. Our data revealed that these compounds triggered morphological changes characteristic of apoptotic cell death. These compounds up-regulated bax and caspase3 expression and down-regulated cyclin D1, bcl2, VEGFA, c-myc and survivin. Moreover, cell population increased at the G1 phase, and a number of cells at the G2/M phase of the cell cycle decreased after treatment. CONCLUSION: All these data suggest that phenolic compounds have a cytotoxic effect on gastric cancer cells and could trigger apoptosis. Besides cytotoxic activity, they could potentially arrest the cell cycle at the G1 phase.

Effect of magnesium on arrhythmia incidence in patients undergoing coronary artery bypass grafting.

BACKGROUND: Cardiac arrhythmia after coronary artery bypass grafting (CABG) surgery is a common complication of cardiac surgery. The effect of serum magnesium, hypomagnesaemia treatment and prophylactic administration of magnesium in the development and prevention of arrhythmias is controversial and there are many different ideas. This study evaluates the therapeutic effects of magnesium in cardiac arrhythmia after CABG surgery. METHODS: The clinical trial enrolled 250 patients who underwent CABG. Based on the initial serum levels of magnesium, patients were divided into two groups: hypomagnesium and normomagnesium. Based on bioethics committee requirements, patients in the hypo-magnesium group received magnesium treatments until they attained normal magnesium blood levels. Both groups underwent CABG with normal blood levels of magnesium. After surgery, each group was randomly divided into two subgroups: one subgroup received a bolus dose of magnesium sulphate (30 mg/kg in 5 min) and the other subgroup received a placebo. Subgroups were under observation in the intensive care unit for 3 days and arrhythmias were recorded. Data from all four subgroups were analysed statistically and interpreted. RESULTS: The results of this study showed that the occurrence of arrhythmia was not significantly different among subgroups (P > 0.05). There was no significant relationship between blood levels of magnesium and arrhythmia during the 3 days post-surgery (P > 0.05). CONCLUSION: The results of this study showed that magnesium sulphate administration did not significantly improve the incidence of arrhythmias in hypo- and normo-magnesium patients after CABG. There was no significant correlation between post-operative serum levels of magnesium and arrhythmia during 3 days.

Potent anti-cancer effects of less polar Curcumin analogues on gastric adenocarcinoma and esophageal squamous cell carcinoma cells.

Curcumin and its chalcone derivatives inhibit the growth of human cancer cells. It is reported that replacement of two OH groups in curcumin with less polar groups like methoxy increases its anti-proliferative activity. In this study, we explored benzylidine cyclohexanone derivatives with non-polar groups, to see if they possess increased anti-cancer activity. Novel 2,6-bis benzylidine cyclohexanone analogues of curcumin were synthesized, and their inhibitory effects on gastric adenocarcinoma (AGS) and esophageal squamous cell carcinoma (KYSE30) cancer cells were studied using an MTT assay. Cell apoptosis was detected by EB/AO staining, and cell cycle was analyzed by flow cytometry. Real-time PCR was performed for gene expression analysis. All synthesized analogues were cytotoxic toward gastric and esophageal cancer cells and showed lower IC50 values than curcumin. Treatment with 2,6-Bis-(3-methoxy-4-propoxy-benzylidene)-cyclohexanone (BM2) was 17 times more toxic than curcumin after 48 h incubation. All novel compounds were more effective than curcumin in apoptosis induction and cell cycle arrest at G1 phase. These results suggest that less polar analogues of curcumin have potent cytotoxicity in vitro. However, they need to be investigated further, especially with animal tumor models, to confirm their chemotherapeutic activity in vivo.

Overexpression of Drosha, DiGeorge syndrome critical region gene 8 (DGCR8), and Dicer mRNAs in the pathogenesis of psoriasis.

INTRODUCTION: Psoriasis is a complex autoimmune inflammatory disease that occurs in genetically susceptible individuals and presents with the development of inflammatory plaques on the skin. Recent studies have indicated that microRNAs (miRNAs) play important roles in psoriasis. OBJECTIVE: To investigate whether expression of Drosha, DGCR8, and Dicer mRNAs is involved in the pathogenesis of psoriasis. METHODS: Biopsies were obtained from involved psoriatic skin (PP), noninvolved psoriatic skin (PN), and healthy skin (NN). Expression of Drosha, Dicer, and DGCR8 was assessed with real-time quantitative real-time PCR in 25 patients with psoriasis and 25 healthy volunteers. RESULTS: We observed that expression levels of Drosha, Dicer, and DGCR8 were upregulated in patients with psoriasis compared to the control group. However, the Drosha and Dicer expression levels were higher in PP tissues and PN tissues compared to NN tissues, but they were more upregulated in PP tissues compared to PN tissues (P<.001). Although the DGCR8 expression was higher in PP tissues and PN tissues compared to NN tissues, it was more upregulated in PN tissues compared to PP tissues (P<.001). CONCLUSION: Our data demonstrate that upregulated expression of Drosha, DGCR8, and Dicer mRNAs may be involved in the pathogenesis of psoriasis.

CRISPR-Cas9 Mediated NOX4 Knockout Inhibits Cell Proliferation and Invasion in HeLa Cells.

Increased expression of NOX4 protein is associated with cancer progression and metastasis but the role of NOX4 in cell proliferation and invasion is not fully understood. We generated NOX4 knockout HeLa cell lines using the CRISPR-Cas9 gene editing system to explore the cellular functions of NOX4. After transfection of CRISPR-Cas9 construct, we performed T7 endonuclease 1 assays and DNA sequencing to generate and identify insertion and deletion of the NOX4 locus. We confirmed the knockout of NOX4 by Western blotting. NOX4 knockout cell lines showed reduced cell proliferation with an increase of sub-G1 cell population and the decrease of S/G2/M population. Moreover, NOX4 deficiency resulted in a dramatic decrease in invadopodium formation and the invasive activity. In addition, NOX4 deficiency also caused a decrease in focal adhesions and cell migration in HeLa cells. These results suggest that NOX4 is required for both efficient proliferation and invasion of HeLa cells.

Epigenetic Modifications and Therapy in Multiple Sclerosis.

Breakthroughs in genetic studies, like whole human genome sequencing and genome-wide association studies (GWAS), have richened our knowledge of etiopathology of autoimmune diseases (AID) through discovery of genetic patterns. Nonetheless, the precise etiology of autoimmune diseases remains largely unknown. The lack of complete concordance of autoimmune disease in identical twins suggests that non-genetic factors also play a major role in determining disease susceptibility. Although there is no certain definition, epigenetics has been known as heritable alterations in gene function without changes in the nucleotide sequence. DNA methylation, histone modifications, and microRNA-associated gene expression suppression are the central mechanisms for epigenetic regulations. Multiple sclerosis (MS) is a disorder of the central nervous system (CNS), characterized by both inflammatory and neurodegenerative features. Although studies on epigenetic alterations in MS only began in the past decade, a mounting number of surveys suggest that epigenetic changes may be involved in the initiation and development of MS, probably through bridging the effects of environmental risk factors to genetics. Arming with clear understanding of epigenetic dysregulations underpins development of epigenetic therapies. Identifying agents inhibiting the enzymes controlling epigenetic modifications, particularly DNA methyltransferases and histone deacetylases, will be promising therapeutic tool toward MS. In the article underway, it is aimed to go through the recent progresses, attempting to disclose how epigenetics associates with the pathogenesis of MS and how can be used as therapeutic approach.

The role of talin2 in breast cancer tumorigenesis and metastasis.

Recent studies show that talin2 has a higher affinity to ß-integrin tails and is indispensable for traction force generation and cell invasion. However, its roles in cell migration, cancer cell metastasis and tumorigenesis remain to be determined. Here, we used MDA-MB-231 human breast cancer cells as a model to define the roles of talin2 in cell migration, invasion, metastasis and tumorigenesis. We show here that talin2 knockdown (KD) inhibited cell migration and focal adhesion dynamics, a key step in cell migration, and that talin2 knockout (KO) inhibited cell invasion and traction force generation, the latter is crucial for cell invasion. Re-expression of talin2WT in talin2-KO cells restored traction force generation and cell invasion, but that of talin2S339C, a ß-integrin-binding deficient mutant, did not. Moreover, talin2 KO (or KD) suppressed tumorigenesis and metastasis in mouse xenograft models. However, surprisingly, re-expression of talin2WT in talin2-KO cells did not rescue tumorigenesis. Thus, talin2 is required for breast cancer cell migration, invasion, metastasis and tumorigenesis, although exogenous expression of high levels of talin2 could inhibit tumorigenesis.

Talin2-mediated traction force drives matrix degradation and cell invasion.

Talin binds to ß-integrin tails to activate integrins, regulating cell migration, invasion and metastasis. There are two talin genes, TLN1 and TLN2, encoding talin1 and talin2, respectively. Talin1 regulates focal adhesion dynamics, cell migration and invasion, whereas the biological function of talin2 is not clear and, indeed, talin2 has been presumed to function redundantly with talin1. Here, we show that talin2 has a much stronger binding to ß-integrin tails than talin1. Replacement of talin2 Ser339 with Cys significantly decreased its binding to ß1-integrin tails to a level comparable to that of talin1. Talin2 localizes at invadopodia and is indispensable for the generation of traction force and invadopodium-mediated matrix degradation. Ablation of talin2 suppressed traction force generation and invadopodia formation, which were restored by re-expressing talin2 but not talin1. Furthermore, re-expression of wild-type talin2 (but not talin2S339C) in talin2-depleted cells rescued development of traction force and invadopodia. These results suggest that a strong interaction of talin2 with integrins is required to generate traction, which in turn drives invadopodium-mediated matrix degradation, which is key to cancer cell invasion.

p70S6K1 (S6K1)-mediated Phosphorylation Regulates Phosphatidylinositol 4-Phosphate 5-Kinase Type I γ Degradation and Cell Invasion.

Phosphatidylinositol 4-phosphate 5-kinase type I γ (PIPKIγ90) ubiquitination and subsequent degradation regulate focal adhesion assembly, cell migration, and invasion. However, it is unknown how upstream signals control PIPKIγ90 ubiquitination or degradation. Here we show that p70S6K1 (S6K1), a downstream target of mechanistic target of rapamycin (mTOR), phosphorylates PIPKIγ90 at Thr-553 and Ser-555 and that S6K1-mediated PIPKIγ90 phosphorylation is essential for cell migration and invasion. Moreover, PIPKIγ90 phosphorylation is required for the development of focal adhesions and invadopodia, key machineries for cell migration and invasion. Surprisingly, substitution of Thr-553 and Ser-555 with Ala promoted PIPKIγ90 ubiquitination but enhanced the stability of PIPKIγ90, and depletion of S6K1 also enhanced the stability of PIPKIγ90, indicating that PIPKIγ90 ubiquitination alone is insufficient for its degradation. These data suggest that S6K1-mediated PIPKIγ90 phosphorylation regulates cell migration and invasion by controlling PIPKIγ90 degradation.