Molecular and nanoscale evaluation of N-cadherin expression in invasive bladder cancer cells under control conditions or GW501516 exposure

E2F1 induced neuroblastoma cell migration and invasion via activation of CENPE/FOXM1 signaling pathway

Background: Neuroblastoma (NB) is a common malignancy occurring in infants and young children. Centrosome-associated protein E (CENPE) is a kinetochore-related motor protein highly expressed in NB, with the mechanism largely unknown. This study is committed to investigating the role and mechanism of CENPE in NB.Method: Short hairpin RNAs targeting CENPE and E2F transcription factor 1 (shCENPE and shE2F1) and CENPE overexpression plasmid were transfected into IMR-32 and SK-N-SH cells. The mRNA expressions of CENPE, N-Cadherin, Vimentin, and proliferating cell nuclear antigen (PCNA) in NB cells were detected by qRT-PCR. The viability, migration, and invasion of cells were tested through cell function experiments. Western blot was applied to detect the protein levels of N-Cadherin, Vimentin, PCNA, CENPE and Forkhead box M1 (FOXM1). The relationship between CENPE and E2F1 was verified by dual-luciferase reporter assay, while the interaction between FOXM1 and CENPE in NB cells was analyzed by rescue experiments.Results: CENPE expression was upregulated in NB cells from metastatic sites. Silencing of CENPE suppressed the NB cell viability, migration, and invasion; and decreased N-Cadherin, Vimentin and PCNA expressions, while overexpressed CENPE did oppositely. E2F1 positively targeted CENPE and CENPE partly reversed the effects of shE2F1 on repressing NB cell viability, migration, invasion and the activation of CENPE/FOXM1 signaling pathway. In addition, silenced FOXM1 partly offset the effects of CENPE on promoting NB cell migration and invasion.Conclusion: E2F1 induces NB cell migration and invasion via activating CENPE/FOXM1 pathway.

GW501516-Mediated Targeting of Tetraspanin 15 Regulates ADAM10-Dependent N-Cadherin Cleavage in Invasive Bladder Cancer Cells

Bladder cancer aggressiveness is correlated with abnormal N-cadherin transmembrane glycoprotein expression. This protein is cleaved by the metalloprotease ADAM10 and the γ-secretase complex releasing a pro-angiogenic N-terminal fragment (NTF) and a proliferation-activating soluble C-terminal fragment (CTF2). Tetraspanin 15 (Tspan15) is identified as an ADAM10-interacting protein to induce selective N-cadherin cleavage. We first demonstrated, in invasive T24 bladder cancer cells, that N-cadherin was cleaved by ADAM10 generating NTF in the extracellular environment and leaving a membrane-anchored CTF1 fragment and that Tspan15 is required for ADAM10 to induce the selective N-cadherin cleavage. Targeting N-cadherin function in cancer is relevant to preventing tumor progression and metastases. For antitumor molecules to inhibit N-cadherin function, they should be complete and not cleaved. We first showed that the GW501516, an agonist of the nuclear receptor PPARβ/δ, decreased Tspan15 and prevented N-cadherin cleavage thus decreasing NTF. Interestingly, the drug did not modify ADAM10 expression, which was important because it could limit side effects since ADAM10 cleaves numerous substrates. By targeting Tspan15 to block ADAM10 activity on N-cadherin, GW501516 could prevent NTF pro-tumoral effects and be a promising molecule to treat bladder cancer. More interestingly, it could optimize the effects of the N-cadherin antagonists those such as ADH-1 that target the N-cadherin ectodomain.

[18F]AlF-NOTA-ADH-1: A new PET molecular radiotracer for imaging of N-cadherin-positive tumors

Background

The cell adhesion molecule (CAM) N-cadherin has become an important target for tumor therapy. The N-cadherin antagonist, ADH-1, exerts significant antitumor activity against N-cadherin-expressing cancers.

Methods

In this study, [¹⁸F]AlF-NOTA-ADH-1 was radiosynthesized. An in vitro cell binding test was performed, and the biodistribution and micro-PET imaging of the probe targeting N-cadherin were also studied in vivo.

Results

Radiolabeling of ADH-1 with [¹⁸F]AlF achieved a yield of up to 30% (not decay-corrected) with a radiochemical purity of >97%. The cell uptake study showed that Cy3-ADH-1 binds to SW480 cells but weakly binds to BXPC3 cells in the same concentration range. The biodistribution results demonstrated that [¹⁸F]AlF-NOTA-ADH-1 had a good tumor/muscle ratio (8.70±2.68) in patient-derived xenograft (PDX) tumor xenografts but a lower tumor/muscle ratio (1.91±0.69) in SW480 tumor xenografts and lowest tumor/muscle ratio (0.96±0.32) in BXPC3 tumor xenografts at 1 h post-injection (p.i.) These findings were in accordance with the immunohistochemistry results. The micro PET imaging results revealed good [18F]AlF-NOTA-ADH-1 tumor uptake in pancreatic cancer PDX xenografts with strong positive N-calcium expression, while lower tumor uptake in SW480 xenografts with positive expression of N-cadherin, and significantly lower tumor uptake in BXPC3 xenografts with low expression of N-cadherin, which was consistent with the biodistribution and immunohistochemistry results. The N-cadherin-specific binding of [18F]AlF-NOTA-ADH-1 was further verified by a blocking experiment involving coinjection of a non radiolabeled ADH-1 peptide, resulting in a significant reduction in tumor uptake in PDX xenografts and SW480 tumor.

Conclusion

[¹⁸F]AlF-NOTA-ADH-1 was successfully radiosynthesized, and Cy3-ADH-1 showed favorable N-cadherin-specific targeting ability by in vitro data. The biodistribution and microPET imaging of the probe further showed that [18F]AlF-NOTA-ADH-1 could discern different expressions of N-cadherin in tumors. Collectively, the findings demonstrated the potential of [¹⁸F]AlF-NOTA-ADH-1 as a PET imaging probe for non-invasive evaluation of the N-cadherin expression in tumors.

KLF5-mediated aquaporin 3 activated autophagy to facilitate cisplatin resistance of gastric cancer

BACKGROUND

Resistance to chemotherapeutic drugs limits the control of gastric cancer (GC) development. The study intended to probe into the mechanism of aquaporin 3 (AQP3) on the chemoresistance of GC.

METHODS

Cisplatin (CDDP)-resistant cells were constructed. Parental AGS and HGC-27 cells and their respective CDDP-resistant cells were transfected with AQP3 overexpression plasmid, AQP3 short hairpin RNA (sh-AQP3) and sh-Kruppel-like factor 5 (shKLF5). The expressions of AQP3 and factors related to autophagy (LC3 I, LC3 II, Atg5, Beclin-1, p62)/epithelial-mesenchymal transition (EMT; E-cadherin and snail) were assessed by Western blot and qRT-PCR. Cell counting kit-8 assay was adopted to test cell viability and half maximal inhibitory concentration (IC 50) was determined. Transwell assay was used for the examination of cell migration and invasion. The regulatory relationship of AQP3 and KLF5 was tested by chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays.

RESULTS

AQP3 was highly-expressed in GC cells and its level was even higher in CDDP-resistant GC cells. AQP3 silencing inhibited viability, autophagy and EMT in CDDP-resistant GC cells, while AQP3 overexpression had the opposite effect. KLF5 positively modulated AQP3 in GC cells resistant to CDDP. KLF5 knockdown reversed AQP3-induced autophagy, viability, migration, invasion and EMT in CDDP-resistant GC cells.

CONCLUSION

KLF5-modulated AQP3 activated autophagy to facilitate the resistance of GC to CDDP.

Peroxisome Proliferator-Activated Receptors and the Hallmarks of Cancer

Peroxisome proliferator-activated receptors (PPARs) function as nuclear transcription factors upon the binding of physiological or pharmacological ligands and heterodimerization with retinoic X receptors. Physiological ligands include fatty acids and fatty-acid-derived compounds with low specificity for the different PPAR subtypes (alpha, beta/delta, and gamma). For each of the PPAR subtypes, specific pharmacological agonists and antagonists, as well as pan-agonists, are available. In agreement with their natural ligands, PPARs are mainly focused on as targets for the treatment of metabolic syndrome and its associated complications. Nevertheless, many publications are available that implicate PPARs in malignancies. In several instances, they are controversial for very similar models. Thus, to better predict the potential use of PPAR modulators for personalized medicine in therapies against malignancies, it seems necessary and timely to review the three PPARs in relation to the didactic concept of cancer hallmark capabilities. We previously described the functions of PPAR beta/delta with respect to the cancer hallmarks and reviewed the implications of all PPARs in angiogenesis. Thus, the current review updates our knowledge on PPAR beta and the hallmarks of cancer and extends the concept to PPAR alpha and PPAR gamma.

Disentangling cadherin-mediated cell-cell interactions in collective cancer cell migration

Cell dispersion from a confined area is fundamental in a number of biological processes, including cancer metastasis. To date, a quantitative understanding of the interplay of single-cell motility, cell proliferation, and intercellular contacts remains elusive. In particular, the role of E- and N-cadherin junctions, central components of intercellular contacts, is still controversial. Combining theoretical modeling with in vitro observations, we investigate the collective spreading behavior of colonies of human cancer cells (T24). The spreading of these colonies is driven by stochastic single-cell migration with frequent transient cell-cell contacts. We find that inhibition of E- and N-cadherin junctions decreases colony spreading and average spreading velocities, without affecting the strength of correlations in spreading velocities of neighboring cells. Based on a biophysical simulation model for cell migration, we show that the behavioral changes upon disruption of these junctions can be explained by reduced repulsive excluded volume interactions between cells. This suggests that in cancer cell migration, cadherin-based intercellular contacts sharpen cell boundaries leading to repulsive rather than cohesive interactions between cells, thereby promoting efficient cell spreading during collective migration.

Overexpressed versican promoted cell multiplication, migration and invasion in gastric cancer

Versican (VCAN) is verified to promote development among many cancers, whose function on gastric cancer (GC) is less studied. This work explored the effect of VCNA on GC. The differentially expressed VCAN between tumor and normal samples, among different cancer stages and the overall survival of GC patients with high and low VCAN levels were predicted through Gene Expression Profiling Interactive Analysis 2 (GEPIA2). The association between VCAN and clinicopathological parameters was analyzed by clinical investigation. AGS and NCI-N87 cells were transfected with VCAN short hairpin RNA (shVCAN) and VCAN overexpression plasmid. The VCNA, Cyclin D1, Cyclin E, E-Cadherin, N-Cadherin and Vimentin expression was detected through quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot. Cell viability was assessed through MTT assay. Cell migration was measured by wound healing assay and cell invasion was evaluated through Transwell assay. Cell cycle was determined by flow cytometry assay. VCAN was upregulated in GC and its high expression related to advanced TNM stage, Lymph node metastasis, Depth of invasion and Grade. VCAN knockdown inhibited multiplication, migration, invasion, Cyclin D1, Cyclin E, N-Cadherin and Vimentin expression while induced cycle arrest and E-Cadherin level of GC cells, whereas overexpressed VCAN showed opposite results. VCAN had a potential to be a biomarker for GC and overexpressed VCAN promoted GC cell multiplication, migration and invasion.

Topology Challenge for the Assessment of Living Cell Deposits with Shear Bulk Acoustic Biosensor

Shear bulk acoustic type of resonant biosensors, such as the quartz crystal microbalance (QCM), give access to label-free in-liquid analysis of surface interactions. The general understanding of the sensing principles was inherited from past developments in biofilms measurements and applied to cells while keeping the same basic assumptions. Thus, the biosensor readouts are still quite often described using 'mass' related terminology. This contribution aims to show that assessment of cell deposits with acoustic biosensors requires a deep understanding of the sensor transduction mechanism. More specifically, the cell deposits should be considered as a structured viscoelastic load and the sensor response depends on both material and topological parameters of the deposits. This shifts the paradigm of acoustic biosensor away from the classical mass loading perspective. As a proof of the concept, we recorded QCM frequency shifts caused by blood platelet deposits on a collagen surface under different rheological conditions and observed the final deposit shape with atomic force microscopy (AFM). The results vividly demonstrate that the frequency shift is highly impacted by the platelet topology on the bio-interface. We support our findings with numerical simulations of viscoelastic unstructured and structured loads in liquid. Both experimental and theoretical studies underline the complexity behind the frequency shift interpretation when acoustic biosensing is used with cell deposits.