Annexin A2 Coordinates STAT3 to Regulate the Invasion and Migration of Colorectal Cancer Cells In Vitro

Açaí (Euterpe oleracea Mart.) Seed Oil Exerts a Cytotoxic Role over Colorectal Cancer Cells: Insights of Annexin A2 Regulation and Molecular Modeling

Açaí, Euterpe oleracea Mart., is a native plant from the Amazonian and is rich in several phytochemicals with anti-tumor activities. The aim was to analyze the effects of açaí seed oil on colorectal adenocarcinoma (ADC) cells. In vitro analyses were performed on CACO-2, HCT-116, and HT-29 cell lines. The strains were treated with açaí seed oil for 24, 48, and 72 h, and cell viability, death, and morphology were analyzed. Molecular docking was performed to evaluate the interaction between the major compounds in açaí seed oil and Annexin A2. The viability assay showed the cytotoxic effect of the oil in colorectal adenocarcinoma cells. Acai seed oil induced increased apoptosis in CACO-2 and HCT-116 cells and interfered with the cell cycle. Western blotting showed an increased expression of LC3-B, suggestive of autophagy, and Annexin A2, an apoptosis regulatory protein. Molecular docking confirmed the interaction of major fatty acids with Annexin A2, suggesting a role of açaí seed oil in modulating Annexin A2 expression in these cancer cell lines. Our results suggest the anti-tumor potential of açaí seed oil in colorectal adenocarcinoma cells and contribute to the development of an active drug from a known natural product.

Nectin2 influences cell apoptosis by regulating ANXA2 expression in neuroblastoma

Neuroblastoma (NB) is a pediatric cancer of the peripheral sympathetic nervous system and represents the most frequent solid malignancy in infants. Nectin2 belongs to the immunoglobulin superfamily and has been shown to play a role in tumorigenesis. In the current study, we demonstrate that serum Nectin2 level is increased in NB patients compared with that in healthy controls and Nectin2 level is correlated with neuroblastoma international neuroblastoma staging system (INSS) classification. There is a positive correlation between Nectin2 level and shorter overall survival in NB patients. Knockdown of Nectin2 reduces the migration of SH-SY5Y and SK-N-BE2 cells and induces their apoptosis and cell cycle arrest. RNA-seq analysis demonstrates that Nectin2 knockdown affects the expressions of 258 genes, including 240 that are upregulated and 18 that are downregulated compared with negative controls. qRT-PCR and western blot analysis confirm that ANXA2 expression is decreased in Nectin2-knockdown SH-SY5Y cells, consistent with the RNA-seq results. ANXA2 overexpression rescues the percentage of apoptotic NB cells induced by Nectin2 knockdown and compensates for the impact of Nectin2 knockdown on cleaved caspase3 and bax expressions. In addition, western blot analysis results show that ANXA2 overexpression rescues the effect of Nectin2 knockdown on MMP2 and MMP9 expressions. The current data highlight the importance of Nectin2 in NB progression and the potential of Nectin2 as a novel candidate target for gene therapy.

The Research Advances of Aptamers in Hematologic Malignancies

Currently, research for hematological malignancies is very intensive, with many breakthroughs. Among them, aptamer-based targeted therapies could be counted. Aptamer is a targeting tool with many unique advantages (easy synthesis, low toxicity, easy modification, low immunogenicity, nano size, long stability, etc.), therefore many experts screened corresponding aptamers in various hematological malignancies for diagnosis and treatment. In this review, we try to summarize and provide the recent progress of aptamer research in the diagnosis and treatment of hematologic malignancies. Until now, 29 aptamer studies were reported in hematologic malignancies, of which 12 aptamers were tested in vivo and the remaining 17 aptamers were only tested in vitro. In this case, 11 aptamers were combined with chemotherapeutic drugs for the treatment of hematologic malignancies, 4 aptamers were used in combination with nanomaterials for the diagnosis and treatment of hematologic malignancies, and some studies used aptamers for the targeted transportation of siRNA and miRNA for targeted therapeutic effects. Their research provides multiple approaches to achieve more targeted goals. These findings show promising and encouraging future for both hematological malignancies basic and clinical trials research.

LncRNA MIR155HG induces M2 macrophage polarization and drug resistance of colorectal cancer cells by regulating ANXA2

OBJECTIVE

To investigate the effects of lncRNA MIR155HG and Annexin A2 (ANXA2) on colorectal cancer (CRC) and the mechanism of the MIR155HG/ANXA2 axis.

METHODS

The expressions of MIR155HG and ANXA2 in human CRC tissues were analyzed for association with pathological characteristics and prognosis of CRC patients. CRC cell lines (Caco2 and HT29) were used to study the effects of MIR155HG or ANXA2 knockdown on tumor cell behaviors and macrophage polarization as well as the effect of M2 polarization on oxaliplatin resistance of CRC cells. RNA immunoprecipitation, RNA pull-down and dual-luciferase reporter assays were applied to verify the targeting relationships among MIR155HG, miR-650 and ANXA2. Heterotopic xenograft models were established to verify the results of cell experiments.

RESULTS

MIR155HG and ANXA2 were highly expressed in CRC tissues/cells and of prognostic values for CRC patients. Knockdown of MIR155HG or ANXA2 suppressed M2 macrophage polarization, and proliferation, migration, invasion and oxaliplatin resistance of CRC cells. MIR155HG competed with ANXA2 for binding miR-650 and can also directly target ANXA2. Knockdown of MIR155HG or ANXA2 also inhibited M2 macrophage polarization and CRC progression in nude mice.

CONCLUSION

This study highlighted that MIR155HG, by regulating the miR-650/ANXA2 axis, promotes CRC progression and enhances oxaliplatin resistance in CRC cells through M2 macrophage polarization.

TAGLN2 promotes the proliferation, invasion, migration and epithelial-mesenchymal transition of colorectal cancer cells by activating STAT3 signaling through ANXA2

Colorectal cancer (CRC) is one of the leading causes of cancer-associated mortality worldwide and currently ranks third in the USA in terms of prevalence. Transgelin-2 (TAGLN2) was previously reported to serve as a tumor promoter in various types of cancer. The present study aimed to investigate the role of TAGLN2 in the progression of CRC and to determine the potential underlying mechanism. The expression level of TAGLN2 in CRC cells (HCT116, SNU-C1, LoVo and SW480) were first detected by reverse transcription quantitative PCR and western blotting. Following TAGLN2 knockdown through transfection with short hairpin (sh)RNAs against TAGLN2, CRC cell proliferation was determined using Cell Counting Kit-8 and 5′-ethynyl-2′-deoxyuridine assays. Cell migration and invasion were evaluated using wound healing and Transwell assays, respectively. The expression levels of matrix metalloproteinase (MMP)2, MMP9 and proteins associated with epithelial-mesenchymal transition (EMT), including N-cadherin (N-cad), vimentin, zinc finger E-box binding homeobox 2 (ZEB2) and E-cadherin (E-cad), were also evaluated by western blotting. Furthermore, following TAGLN2 overexpression and the use of signal transducer and activator of transcription 3 (STAT3) inhibitors to treat CRC cells, all the aforementioned biological parameters were evaluated. The potential relationship between annexin 2 (ANXA2) and STAT3 was confirmed by western blotting analysis. The expression level of TAGLN2 was found to be particularly high in CRC cells. Following TAGLN2 knockdown, CRC cell proliferation, migration, invasion and EMT were significantly inhibited. TAGLN2 knockdown also suppressed STAT3 phosphorylation in CRC cells. In addition, the promoting effects of TAGLN2 overexpression on the progression of CRC were reversed by STAT3 inhibitor. Furthermore, ANXA2 was positively associated with STAT3. Taken together, these findings demonstrated that TAGLN2 could promote the proliferation, invasion, migration and EMT of CRC cells by activating STAT3 and regulating ANXA2 expression. This may reveal the underlying mechanism by which TAGLN2 might regulate the progression of CRC and provide potential therapeutic targets for the treatment of CRC.

RNA packaging into extracellular vesicles: An orchestra of RNA-binding proteins?

Extracellular vesicles (EVs) are heterogeneous membranous particles released from the cells through different biogenetic and secretory mechanisms. We now conceive EVs as shuttles mediating cellular communication, carrying a variety of molecules resulting from intracellular homeostatic mechanisms. The RNA is a widely detected cargo and, impressively, a recognized functional intermediate that elects EVs as modulators of cancer cell phenotypes, determinants of disease spreading, cell surrogates in regenerative medicine, and a source for non-invasive molecular diagnostics. The mechanistic elucidation of the intracellular events responsible for the engagement of RNA into EVs will significantly improve the comprehension and possibly the prediction of EV "quality" in association with cell physiology. Interestingly, the application of multidisciplinary approaches, including biochemical as well as cell-based and computational strategies, is increasingly revealing an active RNA-packaging process implicating RNA-binding proteins (RBPs) in the sorting of coding and non-coding RNAs. In this review, we provide a comprehensive view of RBPs recently emerging as part of the EV biology, considering the scenarios where: (i) individual RBPs were detected in EVs along with their RNA substrates, (ii) RBPs were detected in EVs with inferred RNA targets, and (iii) EV-transcripts were found to harbour sequence motifs mirroring the activity of RBPs. Proteins so far identified are members of the hnRNP family (hnRNPA2B1, hnRNPC1, hnRNPG, hnRNPH1, hnRNPK, and hnRNPQ), as well as YBX1, HuR, AGO2, IGF2BP1, MEX3C, ANXA2, ALIX, NCL, FUS, TDP-43, MVP, LIN28, SRP9/14, QKI, and TERT. We describe the RBPs based on protein domain features, current knowledge on the association with human diseases, recognition of RNA consensus motifs, and the need to clarify the functional significance in different cellular contexts. We also summarize data on previously identified RBP inhibitor small molecules that could also be introduced in EV research as potential modulators of vesicular RNA sorting.

Expression levels and prognostic values of annexins in liver cancer

Annexins are a superfamily of calcium-dependent phospholipid-binding proteins that are implicated in a wide range of biological processes. The annexin superfamily comprises 13 members in humans (ANXAs), the majority of which are frequently dysregulated in cancer. However, the expression patterns and prognostic values of ANXAs in liver cancer are currently largely unknown. The present study aimed to analyze the expression levels of ANXAs and survival data in patients with liver cancer from the Oncomine, GEPIA, Kaplan-Meier plotter and cBioPortal for Cancer Genomics databases. The results demonstrated that ANXA1, A2, A3, A4 and A5 were upregulated, whereas ANXA10 was downregulated in liver cancer compared with normal liver tissues. The expression of ANXA10 was associated with pathological stage. High expression levels of ANXA2 and A5 were significantly associated with poor overall survival (OS) rate whereas ANXA7 and A10 were associated with increased OS. The prognostic values of ANXAs in liver cancer were determined based on sex and clinical stage, which revealed that ANXA2, A5, A7 and A10 were associated with OS in male, but not in female patients. In addition, the potential biological functions of ANXAs were identified by Gene Ontology functional annotation and Kyoto Encyclopedia of Genes Genomes pathway analysis; the results demonstrated that ANXAs may serve a role in liver cancer through the neuroactive ligand-receptor interaction pathway. In conclusion, the results of the present study suggested that ANXA1, A2, A3, A4, A5 and A10 may be potential therapeutic targets for liver cancer treatment, and that ANXA2, A5, A7 and A10 may be potential prognostic biomarkers of liver cancer.

GroEL Protein (Heat Shock Protein 60) of Mycoplasma gallisepticum Induces Apoptosis in Host Cells by Interacting with Annexin A2

Mycoplasma gallisepticum is an avian respiratory and reproductive tract pathogen that has a significant economic impact on the poultry industry worldwide. Although membrane proteins of Mycoplasma spp. are thought to play crucial roles in host interactions, very few have had their biochemical function defined. In this study, we found that the GroEL protein (heat shock protein 60) of Mycoplasma gallisepticum could induce apoptosis in peripheral blood mononuclear cells, and the underlying molecular mechanism was further determined. The GroEL gene from Mycoplasma gallisepticum was cloned and expressed in Escherichia coli to facilitate the functional analysis of recombinant protein. The purified GroEL protein was shown to adhere to peripheral blood mononuclear cells (PBMCs) and DF-1 cells and cause apoptosis in PBMCs. A protein pulldown assay coupled with mass spectrometry identified that annexin A2 possibly interacted with GroEL protein. Coimmunoprecipitation assays confirmed that GroEL proteins could bind to annexin A2, and confocal analysis further demonstrated that GroEL colocolized with annexin A2 in HEK293T cells and PBMCs. Moreover, annexin A2 expression was significantly induced by a recombinant GroEL protein in PBMCs, and knocking down annexin A2 expression resulted in significantly reduced apoptosis. Taken together, these data suggest that GroEL induces apoptosis in host cells by interacting with annexin A2, a novel virulence mechanism in Mycoplasma gallisepticum Our findings lead to a better understanding of molecular pathogenesis in Mycoplasma gallisepticum.

Annexin A2 Expression in Aerogenous Metastasis of Pulmonary Invasive Mucinous Adenocarcinoma: A Case Report including Immunohistochemical Analysis

Aerogenous metastasis (AM) is a form of lung cancer that spreads in a unique fashion, but its mechanisms are still unclear. Annexin A2 (ANX A2), a membrane-binding protein, promotes cancer invasion and is involved in cell adhesion and polarity. The relationship between ANX A2 and cancers with poor stromal invasion capacity has not been studied. We immunohistochemically analyzed ANX A2 expression in AM observed in a patient with pulmonary invasive mucinous adenocarcinoma. In the primary site, ANX A2 immunopositivity on the cell-cell borders weakened as tumor cells projected and separated into alveolar spaces. In AM, tumor cell aggregates with ANX A2 immunopositivity near the surface and within the cytoplasm attached to alveolar epithelial cells, then engulfed them and formed a protrusion. As tumor cell aggregates adhered to the alveolar wall and formed a single layer, cytoplasmic ANX A2-positive products accumulated in the lateral sides of the tumor cells and exhibited distinct membranous positivity. These results indicated that ANX A2 near the tumor cell surface was related to alveolar wall attachment. Furthermore, the translocation of cytoplasmic ANX A2 to cell-cell borders changed cell morphology, adhesion, and polarity restoration.

Rack1 mediates tyrosine phosphorylation of Anxa2 by Src and promotes invasion and metastasis in drug-resistant breast cancer cells

Background

Acquirement of resistance is always associated with a highly aggressive phenotype of tumor cells. Recent studies have revealed that Annexin A2 (Anxa2) is a key protein that links drug resistance and cancer metastasis. A high level of Anxa2 in cancer tissues is correlated to a highly aggressive phenotype. Increased Anxa2 expression appears to be specific in many drug-resistant cancer cells. The functional activity of Anxa2 is regulated by tyrosine phosphorylation at the Tyr23 site. Nevertheless, the accurate molecular mechanisms underlying the regulation of Anxa2 tyrosine phosphorylation and whether phosphorylation is necessary for the enhanced invasive phenotype of drug-resistant cells remain unknown.

Methods

Small interfering RNAs, small molecule inhibitors, overexpression, loss of function or gain of function, rescue experiments, Western blot, wound healing assays, transwell assays, and in vivo metastasis mice models were used to investigate the functional effects of Rack1 and Src on the tyrosine phosphorylation of Anxa2 and the invasion and metastatic potential of drug-resistant breast cancer cells. The interaction among Rack1, Src, and Anxa2 in drug-resistant cells was verified by co-immunoprecipitation assay.

Results

We demonstrated that Anxa2 Tyr23 phosphorylation is necessary for multidrug-resistant breast cancer invasion and metastasis. Rack1 is required for the invasive and metastatic potential of drug-resistant breast cancer cells through modulating Anxa2 phosphorylation. We provided evidence that Rack1 acts as a signal hub and mediates the interaction between Src and Anxa2, thereby facilitating Anxa2 phosphorylation by Src kinase.

Conclusions

Our findings suggest a convergence point role of Rack1/Src/Anxa2 complex in the crosstalk between drug resistance and cancer aggressiveness. The interaction between Anxa2 and Rack1/Src is responsible for the association between drug resistance and invasive/metastatic potential in breast cancer cells. Thus, our findings provide novel insights on the mechanism underlying the functional linkage between drug resistance and cancer aggressiveness.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1147-7) contains supplementary material, which is available to authorized users.

R. R, Thomas S, Nisha P. Short chain fatty acids enriched fermentation metabolites of soluble dietary fibre from Musa paradisiaca drives HT29 colon cancer cells to apoptosis

In this study, the prebiotic potential of soluble dietary fibre extracted from plantain inflorescence (PIF) was investigated. PIF demonstrated prebiotic potential by enhancing the growth of the probiotics under study and thereby hindered colon cancer development. The soluble dietary fibre from Musa paradisiaca inflorescence (PIF) was fermented using Lactobacillus casei and Bifidobacterium bifidum. The fermentation supernatants (LS and BS) were enriched with short chain fatty acids (SCFA) and were able to initiate apoptotic signalling in HT29 colon cancer cells leading to cell death. Both BS and LS exhibited cytotoxic effect; induced DNA damage and enhanced generation of reactive oxygen species in HT29 cells leading to apoptosis. The induction of apoptosis was facilitated by the reduction of membrane potential of mitochondria and ATP synthesis; enhanced delivery of cytochrome c and interference with the expression of pro/antiapoptotic proteins. BS, which exhibited better activity, was further analysed for the identification of differentially regulated proteins by performing two dimensional electrophoresis and MALDI-TOF mass spectrometry. Results emphasized on the fact that, the exposure to BSalteredthe HT29 proteins expression, particularly the upregulation of apoptosis- inducing factor-AIFM1 leading to apoptosis of HT29 cells.

High expression of Anxa2 and Stat3 promote progression of hepatocellular carcinoma and predict poor prognosis

AIM

To elucidate whether the interaction between Anxa2 and Stat3 could promote the progression of hepatocellular carcinoma (HCC) and that high co-expression of Anxa2 and Stat3 could predict poor prognosis in HCC patients.

METHODS

We investigated Anxa2 and Stat3 expression using Western blot analysis in 4 HCC and adjacent nontumor tissues and using immunohistochemistry in 100 patients' paraffin sections. Then we assessed the expression of Stat3, Anxa2 and co-expression of Stat3 and Anxa2 with relevant clinical pathological parameters and their prognostic value in HCC patients. The recurrence and overall survival rates were estimated using the Kaplan-Meier method and compared with the log-rank test. The prognostic analysis was carried out with univariate and multivariate Cox regressions models.

RESULTS

The incidence of high Stat3 expression in HCC tissues (35%) was significantly higher than that in non-HCC tissues (8%) (P < 0.001). The same result was observed in Anxa2 (P < 0.001). Also, the overexpression of Stat3 or Anxa2 showed a significant relationship with the recurrence of the 100 HCC patients (P = 0.012; P = 0.003). Additionally, tumor size >3 cm in diameter, multiple tumor number, and the presence of microvascular tumor thrombus were also significantly associated with recurrence in 100 patients. Then, all enrolled patients were divided into four groups according to IHC score of Stat3 and Anxa2, and the results indicated a significant difference in recurrence time between the subgroups (P < 0.001). What's more, co-highexpression of Stat3 and Anxa2 was related to the presence of microvascular tumor thrombus (P = 0.003) and poor tumor differentiation (P < 0.001), but not relevant with other clinical features (All P > 0.05).

CONCLUSION

The expression of Stat3, Anxa2, or co-high-expression of the two proteins was associated with HCC recurrence and survival.

Screening and characterization of an Annexin A2 binding aptamer that inhibits the proliferation of myeloma cells

Multiple myeloma (MM) is a malignant plasma cell disease and is considered incurable. Annexin A2 (ANXA2) is closely related to the proliferation and adhesion of MM. Using protein-SELEX, we performed a screen for aptamers that bind GST-ANXA2 from a library, and GST protein was used for negative selection. The enrichment of the ssDNA pool was monitored by filter-binding assay during selection. After nine rounds of screening and high-throughput sequencing, we obtained six candidate aptamers that bind to the ANXA2 protein. The affinities of the candidate aptamers for ANXA2 were determined by ELONA. Binding of aptamer wh6 to the ANXA2 protein and to the MM cell was verified by aptamer pulldown experiment and flow cytometry, respectively. Aptamer wh6 binds the ANXA2 protein with good stability and has a dissociation constant in the nanomolar range. The binding specificity of aptamer wh6 was confirmed in vivo in nude mouse xenografts with MM cells and with MM bone marrow aspirates. Furthermore, aptamer wh6 can block MM cell adhesion to ANXA2 and block the proliferation of MM cells induced by ANXA2. In summary, wh6 can be considered a promising candidate tool for MM diagnosis and treatment.

Different Cellular Response of Human Mesothelial Cell MeT-5A to Short-Term and Long-Term Multiwalled Carbon Nanotubes Exposure

Despite being a commercially important product, multiwalled carbon nanotubes (MWCNTs) continue to raise concerns over human health due to their structural similarity to asbestos. Indeed, exposure to MWCNT has been shown to induce lung cancer and even mesothelioma, but contradictory results also exist. To clarify the potentially carcinogenic effects of rigid and rod-like MWCNT and to elucidate the underlying mechanisms, the effects of MWCNT on human mesothelial cell MeT-5A were examined throughout 3 months of continuous exposure, including cytotoxicity, genotoxicity, and cell motility. It was found that MWCNT did not affect MeT-5A cell proliferation at 10 μg/cm² within 72 h treatment, but under the same condition, MWCNT induced genotoxicity and perturbed cell motility. In addition, MeT-5A cells demonstrated different cellular responses to MWCNT after short-term and long-term exposure. Taken together, our results indicated a possible carcinogenic potential for MWCNT after long-term treatment, in which Annexin family proteins might be involved.

Tyr23 phosphorylation of Anxa2 enhances STAT3 activation and promotes proliferation and invasion of breast cancer cells

PURPOSE

Overexpression of Annexin A2 (Anxa2) is positively correlated with breast cancer progression, drug resistance, and poor prognosis of patients with breast cancer. Tyr23 Phosphorylation by Src-family tyrosine kinase is an important post-translational modification of Anxa2. This modification regulates the subcellular localization and functions of Anxa2 and has significant effects on cell proliferation, migration, and invasion. This study aims at revealing the association of Anxa2-Tyr23 phosphorylation in Anxa2-mediated acceleration of breast cancer progression and their elaborate molecular mechanisms.

METHODS

Cell biological function experiments were performed to determine the effects of Anxa2-Tyr23 Phosphorylation on breast cancer cell proliferation and invasion in vitro and metastasis in vivo. The interaction of Tyr23 phosphorylated Anxa2 and STAT3 was verified by co-immunoprecipitation assay. Related mRNA and protein expression levels of cyclin D1 and MMP2/9 and phosphorylation level of STAT3 were detected.

RESULTS

Anxa2-Tyr23 phosphorylation is necessary for proliferation, invasion, and metastasis of breast cancer cells in vitro and in vivo. Tyr23 phosphorylated Anxa2 binds and enhances the sensitivity of STAT3 activation in response to IL-6, thereby increasing the protein and mRNA expression levels of cyclin D1 and MMP2/9 which are STAT3 key target genes and serve pivotal regulatory functions in cell proliferation and invasion, respectively.

CONCLUSION

Our findings further confirmed the regulatory role of Anxa2 and revealed the direct relationship between Anxa2-Tyr23 phosphorylation and activation of STAT3. Moreover, this study provides novel insights into the function of Anxa2-Tyr23 phosphorylation in signal transduction for further understanding of the mechanism through which Anxa2 promotes the progression of breast cancer.

Annexin A2 inhibition suppresses ovarian cancer progression via regulating β-catenin/EMT

Annexin A2 is a member of the Annexin family that acts as a Ca2+-dependent phospholipid and membrane binding protein, which is associated with the survival and spread of multiple neoplasms. However, the function of Annexin A2 in ovarian cancer progression remains unclear. In this study, we aimed to investigate the role and underlying molecular mechanism of Annexin A2 in cell proliferation and invasion in ovarian cancer. We found that the mRNA expression of Annexin A2 was upregulated in ovarian cancer tissues and cell lines. In the loss-of-function of Annexin A2, β-catenin was indicated to be significantly suppressed and EMT constrained. Moreover, cell proliferation and invasion were both markedly inhibited by the downregulation of Annexin A2. Additionally, the overexpression of β-catenin obviously reversed the effect of Annexin A2 on EMT, and cell proliferation and invasion, indicating that Annexin A2 suppression regulated EMT through controlling β-catenin. Taken together, this study showed that Annexin A2 inhibition suppresses proliferation and invasion in ovarian cancer via β-catenin/EMT, proposing the potential role of Annexin A2 in the prevention and treatment of ovarian cancer.