Towards elucidation of functional molecular signatures of the adhesive-migratory phenotype of malignant cells

Biomarkers of tumor invasiveness in proteomics (Review)

Over the past two decades, quantitative proteomics has emerged as an important tool for deciphering the complex molecular events involved in cancers. The number of references involving studies on the cancer metastatic process has doubled since 2010, while the last 5 years have seen the development of novel technologies combining deep proteome coverage capabilities with quantitative consistency and accuracy. To highlight key findings within this huge amount of information, the present review identified a list of tumor invasive biomarkers based on both the literature and data collected on a biocollection of experimental cell lines, tumor models of increasing invasiveness and tumor samples from patients with colorectal or breast cancer. Crossing these different data sources led to 76 proteins of interest out of 1,245 mentioned in the literature. Information on these proteins can potentially be translated into clinical prospects, since they represent potential targets for the development and evaluation of innovative therapies, alone or in combination. Herein, a systematical review of the biology of each of these proteins, including their specific subcellular/extracellular or multiple localizations is presented. Finally, as an important advantage of quantitative proteomics is the ability to provide data on all these molecules simultaneously in cell pellets, body fluids or paraffin‑embedded sections of tumors/invaded tissues, the significance of some of their interconnections is discussed.

Low Molecular Weight Heparin-Coated and Dendrimer-Based Core-Shell Nanoplatform with Enhanced Immune Activation and Multiple Anti-Metastatic Effects for Melanoma Treatment

High-efficiency treatment for tumor is not easy to achieve owing to the existence of metastasis, which remains the arch-criminal of most tumor deaths. Conventional chemotherapy exhibits insufficient inhibitory efficiency on tumor metastasis and more powerful strategies to conquer metastatic tumors are urgently needed. In this study, a rational chemoimmunotherapy strategy was adopted to treat highly aggressive melanoma based on a newly developed multifunctional nanoplatform. Firstly, immunoadjuvant cytosine-phosphate-guanine oligonucleotides (CpG ODNs) were used to boost the doxorubicin (DOX)-elicited immune responses, which synergistically suppressed tumor growth and metastasis. And the anti-metastatic low molecular weight heparin (LMWH) was also integrated, thus multiple anti-metastatic effects to against tumor metastasis were achieved. Methods: G4 PAMAM was serving as the main support to conjugate DOX by pH-sensitive hydrazone bond (PPD) and the synthesized conjugates were confirmed by ¹H-NMR spectra, IR spectra and HRMS. Immunoadjuvant CpG ODNs were loaded by electrostatic adsorption to formulate PPD/CpG. After the coating of anti-metastatic LMWH, the designed LMWH/PPD/CpG was fabricated and characterized. The platelets-related and platelets-unrelated anti-metastatic mechanisms were investigated on B16F10 the immune activation effects, anti-tumor and anti-metastatic efficacy of LMWH/PPD/CpG were evaluated on a B16F10 melanoma xenograft model. Results: DOX elicited tumor-specific immune responses by ICD, and the immunological effects could be further promoted by CpG ODNs, exhibiting enhanced maturation of dendritic cells (DCs) and increased level of cytolytic T lymphocytes (CTLs) in vivo. Owing to the coating of LMWH, the platelets-induced epithelial-mesenchymal-like transition of tumor cells was hindered and the actin cytoskeletal arrangement of tumor cells was affected, thus the migration ability of tumor cells was further inhibited. This multifunctional nanoplatform showed enhanced treatment efficiency on melanoma primary tumor and pulmonary metastasis. Conclusion: The immune activation and multiple anti-metastatic effects of LMWH/PPD/CpG establish a novel therapeutic strategy for melanoma. This anti-metastatic nanoplatform could be broadly applied for the co-delivery of other nucleic acids and chemotherapeutic drugs to treat highly aggressive tumors.

Antitumor and Antimetastasis Activities of Heparin-based Micelle Served As Both Carrier and Drug

Effective treatments for tumors are not easy to achieve due to the existence of metastases, which are responsible for most tumor death. Hence, a new drug delivery system is a pressing need, which should be biocompatible, stimuli-responsive, and multifunctional, including antitumor, antimetastasis, and antiangiogenesis effects. However, it is challenging to achieve all of these properties in one drug delivery system. Here, we developed a system of drug DOX and heparin into one self-assemble nanoparticle via pH-sensitive hydrazone bond and hydrophobic groups, deoxycholate. In the process, heparin itself was not only as the hydrophilic segments of the carrier, but also processed multiple biological functions such as antiangiogenesis and antimetastasis effect. The micelle nanoparticle HD-DOX processed good stability and acidic pH-triggered drug release property. After systemic administration, heparin-based micelle nanoparticle showed longer half-time and enhanced accumulation of DOX in tumors through the enhanced permeability and retention effect, leading to more efficient antitumor effects. In addition, heparin could hinder platelet-induced tumor cells epithelial-mesenchymal transition (EMT) and partially affect cell actin cytoskeletal arrangement, resulting in the disorganization of the actin cytoskeleton. Therefore, HD-DOX exhibited significant inhibitory effect on the metastasis in melanoma animal model in C57BL/6 mouse. Meanwhile, benefited from the antiangiogenesis effect of heparin, tube formations in endothelial cells were effectively inhibited and tumor vascular density was decreased by HD-DOX. Taken together, our study developed a self-assembly nanoplatform that both the drug and carrier had therapeutic effects with ideal antitumor efficacy.

Suppression of lysyl-tRNA synthetase, KRS, causes incomplete epithelial-mesenchymal transition and ineffective cell‑extracellular matrix adhesion for migration

The cell-adhesion properties of cancer cells can be targeted to block cancer metastasis. Although cytosolic lysyl-tRNA synthetase (KRS) functions in protein synthesis, KRS on the plasma membrane is involved in cancer metastasis. We hypothesized that KRS is involved in cell adhesion-related signal transduction for cellular migration. To test this hypothesis, colon cancer cells with modulated KRS protein levels were analyzed for cell-cell contact and cell-substrate adhesion properties and cellular behavior. Although KRS suppression decreased expression of cell-cell adhesion molecules, cells still formed colonies without being scattered, supporting an incomplete epithelial mesenchymal transition. Noteworthy, KRS-suppressed cells still exhibited focal adhesions on laminin, with Tyr397-phopshorylated focal adhesion kinase (FAK), but they lacked laminin-adhesion-mediated extracellular signal-regulated kinase (ERK) and paxillin activation. KRS, p67LR and integrin α6β1 were found to interact, presumably to activate ERK for paxillin expression and Tyr118 phosphorylation even without involvement of FAK, so that specific inhibition of ERK or KRS in parental HCT116 cells blocked cell-cell adhesion and cell-substrate properties for focal adhesion formation and signaling activity. Together, these results indicate that KRS can promote cell-cell and cell-ECM adhesion for migration.

Role of receptor for hyaluronic acid-mediated motility (RHAMM) in low molecular weight hyaluronan (LMWHA)-mediated fibrosarcoma cell adhesion

Hyaluronan (HA) modulates key cancer cell functions through interaction with its CD44 and receptor for hyaluronic acid-mediated motility (RHAMM) receptors. HA was recently found to regulate the migration of fibrosarcoma cells in a manner specifically dependent on its size. Here, we investigated the effect of HA/RHAMM signaling on the ability of HT1080 fibrosarcoma cells to adhere onto fibronectin. Low molecular weight HA (LMWHA) significantly increased (p ≤ 0.01) the adhesion capacity of HT1080 cells, which high molecular weight HA inhibited. The ability of HT1080 RHAMM-deficient cells, but not of CD44-deficient ones, to adhere was significantly decreased (p ≤ 0.001) as compared with control cells. Importantly, the effect of LMWHA on HT1080 cell adhesion was completely attenuated in RHAMM-deficient cells. In contrast, adhesion of RHAMM-deficient cells was not sensitive to high molecular weight HA treatment, which identifies RHAMM as a specific conduit of the LMWHA effect. Western blot and real time-PCR analyses indicated that LMWHA significantly increased RHAMM transcript (p ≤ 0.05) and protein isoform levels (53%, 95 kDa; 37%, 73 kDa) in fibrosarcoma cells. Moreover, Western blot analyses showed that LMWHA in a RHAMM-dependent manner enhanced basal and adhesion-dependent ERK1/2 and focal adhesion kinase (FAK) phosphorylation in HT1080 cells. Utilization of a specific ERK1/2 inhibitor completely inhibited (p ≤ 0.001) LMWHA-dependent adhesion, suggesting that ERK1/2 is a downstream effector of LMWHA/RHAMM signaling. Likewise, the utilization of the specific ERK1 inhibitor resulted in a strong down-regulation of FAK activation in HT1080 cells, which identifies ERK1/2 as a FAK upstream activator. In conclusion, our results suggest that RHAMM/HA interaction regulates fibrosarcoma cell adhesion via the activation of FAK and ERK1/2 signaling pathways.

Low molecular weight heparin inhibits melanoma cell adhesion and migration through a PKCa/JNK signaling pathway inducing actin cytoskeleton changes

Low molecular weight heparin (LMWH) has significant antimetastatic capabilities and affects cancer progression in humans through, not fully defined mechanisms. Here we evaluated its activity at the intracellular level and how it is correlated with melanoma cell adhesion and migration. LMWH inhibited M5 and A375 melanoma cell adhesion and migration in a dose-dependent manner (p⩽0.01). Treatment of M5 melanoma cells with LMWH caused a marked down regulation of constitutive as well as the FN-induced phosphorylation (p⩽0.01) of protein kinase C alpha (PKCa). This was associated with a profound decrease in the cytoplasmic pPKCa (p⩽0.05) and a simultaneous enhancement of nuclear pPKCa localization (p⩽0.01). A significant decrease in the levels of pJNK (p⩽0.01), which is a downstream effector of PKCa, was also demonstrated in the LMWH-treated cells. Furthermore, LMWH-treated cells had disorganized actin stress fibers correlated to a strong decrease in cell-substratum interface area (p⩽0.05) and altered morphology. The decrease in the activation of PKCa, which is an important regulator of cell motility, was directly correlated to the reduced ability of the LMWH-treated melanoma cells to adhere onto and migrate towards the fibronectin (FN) substrate (p⩽0.01). The lineage activation of PKCa-JNK/p38 and their correlation to M5 cell adhesion was confirmed with the utilization of specific inhibitors. In conclusion, LMWH through the downregulation of pPKCa and redistribution to nuclear region attenuates JNK activation, which in turn induces cytoskeleton changes correlated to M5 cell decreased adhesion/migration. This may provide clues for the pharmacological targeting of melanoma.