The Role of Drebrin in Cancer Cell Invasion

Magnolol and 5-fluorouracil synergy inhibition of metastasis of cervical cancer cells by targeting PI3K/AKT/mTOR and EMT pathways

Objective

This study is designed to investigate the mode of action of the synergistic effect of 5-fluorouracil (5-FU) and magnolol against cervical cancer.

Methods

Network pharmacological approach was applied to predict the molecular mechanism of 5-FU combined with magnolol against cervical cancer. CCK-8 assay, colony formation assay, immunofluorescence staining, adhesion assay, wound healing mobility assay, cell migration and invasion assay and Western blot analysis were conducted to validate the results of in silico study.

Results

Phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway was identified as the key pathway in silico study. The experimental results showed that 5-FU combined with magnolol strongly inhibited cervical cancer cell proliferation, induced the morphological change of HeLa cells by down-regulating the expression of α-actinin, tensin-2 and vinculin. Moreover, magnolol enhanced inhibitory effect of 5-FU on the cell adhesion, migration and invasion. The phosphorylation of AKT and PI3K and the expression of mTOR were strongly inhibited by the combination of 5-FU and magnolol. Moreover, the expression of E-cadherin and β-catenin was upregulated and the expression of Snail, Slug and vimentin was down-regulated by the 5-FU together with magnolol.

Conclusion

Taken together, this study suggests that 5-FU combined with magnolol exerts a synergistic anti-cervical cancer effect by regulating the PI3K/AKT/mTOR and epithelial-mesenchymal transition (EMT) signaling pathways.

Inhibition of p62 and/or NFE2L2 induced autophagy impaires esophageal squamous cell cancer metastasis by reversing EMT

Esophageal squamous cell carcinoma (ESCC) pathogenesis is influenced by both NFE2L2 (nuclear factor erythroid 2-related factor 2) and SQSTM1 (sequestosome 1), also known as p62. However, while there is evidence that these two proteins can interact with one another in a range of pathological contexts, whether these interactions govern the development or progression of ESCC remains unknown. In the present study, analyses of the GEPIA database revealed the simultaneous upregulation of both NFE2L2 and p62 in ESCC, as was further confirmed through biochemical analyses conducted with a human tumor microarray. Knocking down the expression of one or both of these factors demonstrated that both p62 and NFE2L2 mediate the progression of ESCC, as such downregulation altered the morphological characteristics of these cells and suppressed the epithelial-mesenchymal transition (EMT). Strikingly, these experiments revealed synergistic interactions between NFE2L2 and p62 in the promotion of ESCC invasivity and EMT induction. The treatment of cells with the autophagy inhibitors 3-MA, however, was sufficient to partially reverse the anti-metastatic effects of knocking down p62 and/or NFE2L2. Together, these data illustrate the ability of p62 and NFE2L2 to function in a synergistic manner, promoting ESCC cell metastatic progression and EMT induction through mechanisms linked to autophagic activity. As such, efforts to simultaneously target both of these proteins may represent a viable means of providing new treatment options to ESCC patients.

Basic research on curcumin in cervical cancer: Progress and perspectives

Curcumin is a polyphenolic substance extracted from plants such as Curcuma longa, Curcuma zedoaria, and radix curcumae, and it has attracted much attention because of the anti-inflammatory, antioxidant, anti-tumor, antibacterial and other multiple pharmacological effects. Cervical cancer is one of the most common malignant tumors in women. With the application of HPV (human papillomavirus) vaccine, the incidence of cervical cancer is expected to be reduced, but it remains difficult to promote the vaccine among low-income population. As a commonly used food additive, curcumin has recently been found to have a significant therapeutic effect in the treatment of cervical cancer. In recent years, numerous in vitro and in vivo studies have found that curcumin can have significant efficacy in anti-cervical cancer treatment by promoting apoptosis, inhibiting tumour cell proliferation, metastasis and invasion, inhibiting HPV and inducing autophagy in tumour cells. However, due to poor water solubility, rapid catabolism, and low bioavailability of curcumin, studies on curcumin derivatives and novel formulations are increasing. Curcumin has a wide range of mechanisms of action against cervical cancer and may become a novel antitumor drug in the future, opening up new ideas for the research of curcumin in the field of antitumor. There is a lack of systematic reviews on the mechanism of action of curcumin against cervical cancer. Therefore, this study is a review of the literature based on the mechanism of action of curcumin against cervical cancer, with a view to providing reference information for scientific and clinical practitioners.

Role of K63-linked ubiquitination in cancer

Ubiquitination is a critical type of post-translational modifications, of which K63-linked ubiquitination regulates interaction, translocation, and activation of proteins. In recent years, emerging evidence suggest involvement of K63-linked ubiquitination in multiple signaling pathways and various human diseases including cancer. Increasing number of studies indicated that K63-linked ubiquitination controls initiation, development, invasion, metastasis, and therapy of diverse cancers. Here, we summarized molecular mechanisms of K63-linked ubiquitination dictating different biological activities of tumor and highlighted novel opportunities for future therapy targeting certain regulation of K63-linked ubiquitination in tumor.

PTEN Dual Lipid- and Protein-Phosphatase Function in Tumor Progression

Simple Summary

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a multifunctional tumor suppressor with protein- and lipid-phosphatase activities. The inactivation of PTEN is commonly found in all human cancers and is correlated with tumor progression. PTEN-lipid-phosphatase activity has been well documented to dephosphorylate phosphatidylinositol-3, 4, 5-phosphate (PIP3), which hinders cell growth and survival by dampening the PI3K and AKT signaling activity. PTEN-protein-phosphatase activity is less well studied and understood. Recent studies have reported that PTEN-protein-phosphatase activity dephosphorylates the different proteins and acts in various cell functions. We here review the PTEN mutations and protein-phosphatase substrates in tumor progression. We aim to address the gap in our understanding as to how PTEN protein phosphatase contributes to its tumor-suppression functions.

Abstract

PTEN is the second most highly mutated tumor suppressor in cancer, following only p53. The PTEN protein functions as a phosphatase with lipid- and protein-phosphatase activity. PTEN-lipid-phosphatase activity dephosphorylates PIP3 to form PIP2, and it then antagonizes PI3K and blocks the activation of AKT, while its protein-phosphatase activity dephosphorylates different protein substrates and plays various roles in tumorigenesis. Here, we review the PTEN mutations and protein-phosphatase substrates in tumorigenesis and metastasis. Our purpose is to clarify how PTEN protein phosphatase contributes to its tumor-suppressive functions through PI3K-independent activities.

Drebrin, an actin-binding protein, is required for lens morphogenesis and growth

BACKGROUND

Lens morphogenesis, architecture, and clarity are known to be critically dependent on actin cytoskeleton organization and cell adhesive interactions. There is limited knowledge, however regarding the identity and role of key proteins regulating actin cytoskeletal organization in the lens. This study investigated the role of drebrin, a developmentally regulated actin-binding protein, in mouse lens development by generating and characterizing a conditional knockout (cKO) mouse model using the Cre-LoxP recombination approach.

RESULTS

Drebrin E, a splice variant of DBN1 is a predominant isoform expressed in the mouse lens and exhibits a maturation-dependent downregulation. Drebrin co-distributes with actin in both epithelium and fibers. Conditional deficiency (both haploinsufficiency and complete absence) of drebrin results in disrupted lens morphogenesis leading to cataract and microphthalmia. The drebrin cKO lens reveals a dramatic decrease in epithelial height and width, E-cadherin, and proliferation, and increased apoptotic cell death and expression of α-smooth muscle actin, together with severely impaired fiber cell organization, polarity, and cell-cell adhesion.

CONCLUSIONS

This study demonstrates the requirement of drebrin in lens development and growth, with drebrin deficiency leading to impaired lens morphogenesis and microphthalmia.

Alpha-actinin-4 is essential for maintaining normal trophoblast proliferation and differentiation during early pregnancy

BACKGROUND

Proper differentiation of trophoblasts in the human placenta is essential for a successful pregnancy, whereas abnormal regulation of this process may lead to adverse pregnancy outcomes, especially preeclampsia (PE). However, the underlying mechanism of trophoblast differentiation remains unclear. Previous studies have reported the involvement of alpha-actinin-4 (ACTN4) in the actin cytoskeleton dynamics and motility. Hence, we hypothesized that ACTN4 may act as an important regulator in the normal proliferation and differentiation of trophoblasts during early pregnancy.

METHOD

To test this hypothesis, we collected villous tissues from women undergoing a legal pregnancy termination during 6-10 weeks of gestation and explanted them for cell culture and siRNA transfection. We also obtained placental tissues from PE patients and healthy pregnant women and isolated the primary cytotrophoblast (CTB) cells. The expression of ACTN4 in the CTBs of placental villi and during the differentiation of CTBs into STBs was detected by immunofluorescence, immunohistochemistry (IHC), and EdU proliferation assays. Besides, villous explant, Matrigel invasion, transwell migration assay, and Wound-healing assay were performed to identify the possible role of ACTN4 in the outgrowth of explants and the invasion, migration, and proliferation of cell column trophoblasts (CCTs). Western blot analysis was carried out to compare the protein expression level of AKT, Snail activities, and epithelial-to-mesenchymal transition (EMT) in the villi or HTR8/SVneo cells with ACTN4 knockdown.

RESULTS

ACTN4 was highly expressed in CTB cells and interstitial extravillous trophoblast (iEVT) cells but not found in the syncytiotrophoblast (STB) cells in the first trimester villi. Downregulation of ACTN4 led to reduced trophoblast proliferation and explant outgrowth ex vivo, as well as iEVT invasion and migration in vitro due to disrupt of actin filaments organization. Such ACTN4 inhibition also decreased AKT and Snail activities and further impeded the EMT process. In addition, ACTN4 expression was found to be downregulated in the iEVTs from preeclamptic placentas.

CONCLUSIONS

Our findings suggest that ACTN4 may act as an important regulator of trophoblast proliferation and differentiation during early pregnancy, and dysregulation of this protein may contribute to preeclampsia pathogenesis.

The circular RNA hsa-circ-0072309 plays anti-tumour roles by sponging miR-100 through the deactivation of PI3K/AKT and mTOR pathways in the renal carcinoma cell lines

Aims: To explore the roles and regulatory mechanisms of the circular RNA (circRNA)-hsa-circ-0072309 in CAKI-1 and ACHN cells. Methods: CAKI-1 and ACHN cells were transfected with hsa-circ-0072309 overproduction vector (circRNA) and microRNA-100 (miR-100) mimic or the corresponding controls. Cell viability was detected with the CCK-8. The protein expression levels of p53, c-Myc, cleaved-caspase-3/9, matrix metalloproteinase (MMP)-2/9, vimentin, AKT, PI3K and mTOR were individually determined through western blot. qRT-PCR was used to examine the expressions of hsa-circ-0072309 and miR-100. The apoptotic rate and the migration or invasion rates were separately determined by the annexin v-FITC/PI with a flow cytometer and modified two-chamber migration assay or millicell hanging cell culture. Results: The hsa-circ-0072309 was poorly expressed in tumor tissue. Abundant hsa-circ-0072309 induced the inhibitions of cell proliferation, migration and invasion, as well as the PI3K/AKT and the mTOR cascades but enhancement of apoptosis. circRNA stimulated the down-regulation of miR-100, which was low-expressed in tumour tissue and whose overproduction abolished the impacts of circRNA on these elements mentioned above. Conclusion: The hsa-circ-0072309 played anti-tumour roles by targeting miR-100 by blocking the PI3K/AKT and mTOR cascades in the CAKI-1 and ACHN cell lines.

Hypoxia induces actin cytoskeleton remodeling by regulating the binding of CAPZA1 to F-actin via PIP2 to drive EMT in hepatocellular carcinoma

Studies have shown that hypoxia can induce cytoskeletal injury and remodeling through the activation of the RhoA/ROCK signaling pathway by hypoxia-inducible factor-1α (HIF-1α). Our previous study confirmed that CAPZA1 can modulate EMT by regulating actin cytoskeleton remodeling. However, the relationship between HIF-1α and CAPZA1 has not been illustrated. Therefore, this study aimed to investigate the mechanism by which hypoxia induces the remodeling of the actin cytoskeleton by regulating CAPZA1 in hepatocellular carcinoma (HCC) cells. In the present study, we showed that the low expression of CAPZA1 promotes HCC cell invasion and migration in vitro and in vivo by regulating actin cytoskeleton remodeling to drive EMT. Furthermore, we found that the combination of PIP2 and CAPZA1 enables CAPZA1 to be released from the barbed end of F-actin, which in turn drives the remodeling of the actin cytoskeleton. Finally, we confirmed that hypoxia increases PIP2 levels and its binding to CAPZA1 in HCC cells via the HIF-1α/RhoA/ROCK1 pathway. Thus, CAPZA1 and PIP2 could be therapeutic targets to inhibit the invasion and migration promoted by hypoxia in HCC cells.