Low Metastatic Cells Research Articles

Communication between cancer cell subtypes by exosomes contributes to nasopharyngeal carcinoma metastasis and poor prognosis.

Intratumor heterogeneity is common in cancers, with different cell subtypes supporting each other to become more malignant. Nasopharyngeal carcinoma (NPC), a highly metastatic cancer, shows significant heterogeneity among its cells. This study investigates how NPC cell subtypes with varying metastatic potentials influence each other through exosome-transmitted molecules. Exosomes were purified and characterized. MicroRNA expression was analyzed via sequencing and qRT-PCR. The effects of miR-30a-5p on migration, invasion, and metastasis were evaluated in vitro and in vivo. Its impact on desmoglein glycoprotein (DSG2) was assessed using dual-luciferase assays and Western blotting. Immunohistochemistry (IHC) and statistical models linked miR-30a-5p/DSG2 levels to patient prognosis. Different NPC cell subtypes transmit metastatic potential via exosomes. High-metastatic cells enhance the migration, invasion, and metastasis of low-metastatic cells through exosome-transmitted miR-30a-5p. Plasma levels of exosomal miR-30a-5p are reliable indicators of NPC prognosis. miR-30a-5p may promote metastasis by targeting DSG2 and modulating Wnt signaling. Plasma exosomal miR-30a-5p inversely correlates with DSG2 levels, predicting patient outcomes. High-metastatic NPC cells can increase the metastatic potential of low-metastatic cells through exosome-transmitted miR-30a-5p, which is a valuable prognostic marker assessable via liquid biopsy.

Effect of micropillar density on morphology and migration of low and high metastatic potential breast cancer cells

Study of cell migration in cancer is crucial to the comprehension of the processes and factors that govern tumor spread. Cancer cells migrate invading tissues, causing alterations in cell adhesion, cytoskeleton, and signaling pathways. Little is known about the physical attributes of cancer cells that change when interacting with microenvironments. In this work, the local topography of the ECM has been mimicked through micropillar array substrates. MDA-MB-231 and MCF-7 breast cancer cells, exhibiting high and low metastatic potential, respectively, were analyzed. Differences in morphology and migration of the cells were investigated by examining the cell spreading area, circularity, aspect ratio, migration speed, and migration path. This work encountered that none of the studied cell lines have preferential orientation migrating on uniform patterns. In contrast, cell migration on graded patterns shows preferential orientation along the longitudinal direction from sparser to denser zones which is significantly influenced by substrate stiffness and indicates that both cell lines can sense the spacing gradient and respond to this topographical cue. The migration speed of the breast cancer cell lines significantly decreases from the sparse to medium to dense zones, registering higher values for the MDA-MB-231.

Curbing Breast Cancer by Altering V-ATPase Action on F-Actin, Heterochromatin, ETV7 and mTORC2 Signaling.

Motivated by the vacuolar proton pump's importance in cancer, we investigate the effects of proton pump inhibition on breast cancer cell migration and proliferation, F-actin polymerization, lamin A/C, heterochromatin, and ETV7 expressions, nuclear size and shape, and AKT/mTOR signaling. Lowly metastatic MCF7 and highly metastatic MDA-MB-231 breast cancer cells were treated with 120 nM of proton pump inhibitor Bafilomycin A1 for 24 hours. Cell migration was studied with wound- scratch assays, ATP levels with a chemiluminescent assay; cell proliferation was quantified by a cell area expansion assay. Nuclear size and shape were determined using DAPI nuclear stain and fluorescence microscopy. The levels of F-actin, lamin A/C, heterochromatin, and ETV7 were quantified using both immunocytochemistry and western blots; p-mTORC1, p-mTORC2, mTOR, p-AKT, and AKT were measured by western blots. We reveal that proton pump inhibition reduces F-actin polymerization, cell migration, proliferation, and increases heterochromatin in both lowly and highly metastatic cells. Surprisingly, Bafilomycin decreases lamin A/C in both cell lines. Inhibition has different effects on ETV7 expression in lowly and highly metastatic cells, as well as nuclear area, perimeter, and circularity. Bafilomycin also significantly decreases p-mTORC1, p-MTORC2, and MTOR expression in both cell lines, whereas it significantly decreases p-AKT in lowly metastatic cells and surprisingly significantly increases p-AKT in highly metastatic cells. Our proton pump inhibition protocol reduces V-ATPase levels (~25%) within three hours. V-ATPase levels vary in time for both control and inhibited cells, and inhibition reduces cellular ATP. Proton pumps promote F-actin polymerization and decrease heterochromatin, facilitating invasion. These pumps also upregulate both mTORC1 and mTORC2, thus highlighting the relevance of vacuolar proton pumps as metastatic cancer targets.

Colorectal cancer cells with high metastatic potential drive metastasis by transmitting exosomal miR-20a-3p through modulating NF1/MAPK pathway.

Cancer cells exhibit heterogeneous metastatic potential, and high metastatic (HM) subclones can enhance the metastatic potential of low metastatic subclones by transmitting some factors. Exosomal miRNAs play a pivotal role in the crosstalk of heterogeneous metastatic subclones. This study discovered that miR-20a-3p was upregulated in colorectal adenocarcinoma (CRA), correlated with metastasis, and potentially served as a prognostic indicator for CRA. miR-20a-3p could promote the proliferation, migration, and invasion of CRA cells. Interestingly, HM CRA cells could promote malignant phenotypes of low metastatic CRA cells by transmitting exosomal miR-20a-3p. Mechanically, miR-20a-3p could inhibit neurofibromin 1(NF1), thereby activate the rat sarcoma viral oncogene (RAS)-mediated mitogen-activated protein kinases (MAPK) signaling pathway to drive the metastasis of CRA. In summary, our study provided evidence that colorectal cancer cells with HM potential drive metastasis by transmitting exosomal miR-20a-3p through modulating the NF1/MAPK pathway.

Abstract 5412: In vitro plasticity profiling of metastatic cancer cells with an imaging-based pipeline

Abstract Different types of cancer cells exhibit varying levels of invasiveness, migration behavior and ability to resume growth at distant sites. In order to classify cell lines for these fundamentally important traits of metastasis, we sought to generate an image-based in vitro assay that quantifies morphological and functional features of cancer cell plasticity. We developed an Imaging-Based Pipeline as an R Package for in vitro cell monitoring using the breast cancer cell lines MDA-MB-231 and MCF-7 that represent high-metastatic and low-metastatic cells in vivo, respectively, to identify relevant feature variables. Live cell imaging via the zenCELL owl system captured images for labeling and segmentation. Pre-trained neural network models from Cellpose, combined with user-calibrations, accurately segmented cells for tracking. The tracking pipeline calculated similarity coefficients, Jaccard index, between consecutive frames for cell trajectory analysis. Geometric and morphological features, speed, and distance measurements were derived for assessing structural motility and proliferation-associated changes. The analysis of two cell line models revealed significant variations in morphological changes, with MDA-MB-231 showing more rapid changes between round and elongated shape compared to MCF-7 cells. Moreover, the analysis of cell motility, consistent with the morphological changes, revealed that TGF-beta1 induced migration in MDA-MB-231 cells much stronger than in MCF-7 cells. Likewise, differences in proliferation induction upon addition of growth factor was monitored, showing that MCF-7 cells are more responsive to the growth stimulation than MDA-MB-231 cells. Consequently, the morphological plasticity of cancer cells, closely linked to the epithelial-to-mesenchymal transition (EMT) state, emerges as a defining factor for the in vitro plasticity of these cells. Quantified proliferation rate and migration speed of the cells was then used to establish an in vitro "plasticity index" that captures a cell line’s ability to switch between migration and proliferation. This index will undergo validation using cell lines with well-established metastatic propensities. In conclusion, we developed an Imaging-Based Pipeline that can effectively explore cancer cell plasticity in vitro and monitor the impact of genetic or pharmacologic perturbations on this critical characteristic of aggressive cancer cells. Citation Format: Saba Sameri, Durdam Das, Stefanie Michaelis, Joachim Wegener, Hedayatollah Hosseini, Martin Hoffmann. In vitro plasticity profiling of metastatic cancer cells with an imaging-based pipeline [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5412.

ADAM22 acts as a novel predictive biomarker for unfavorable prognosis and facilitates metastasis via PI3K/AKT signaling pathway in nasopharyngeal carcinoma

BackgroundNasopharyngeal carcinoma (NPC) is a type of epithelial malignancy known for its high likelihood of metastasizing to distant organs, which remains the primary obstacle in the treatment of NPC. The present study aimed to identify potential intervention target for NPC metastasis. MethodsThe differentially expressed genes (DEGs) were firstly analyzed and intersected across various NPC related datasets in the Gene Expression Omnibus database. Subsequently, various techniques including quantitative polymerase chain reaction (qPCR), western blotting, immunohistochemistry, migration and invasion assays, in conjunction with bioinformatics and prognostic modeling, were utilized to elucidate the role of candidate genes in NPC metastasis. ResultsWe discerned the gene a disintegrin and metalloprotease 22 (ADAM22) as a distinct and significant factor in the progression and metastasis of NPC through five datasets. The elevated expression of ADAM22 was observed in clinical tissue and plasma samples with advanced NPC, as well as in high metastatic cells. Furthermore, we highlighted its essential role in a prognostic model that demonstrated strong prediction performance for NPC. Notably, overexpression of ADAM22 was found to enhance the aggressiveness and epithelial-mesenchymal transition (EMT) of low metastatic NPC cells, whereas the downregulation of ADAM22 resulted in suppressed effect in high metastatic cells. Delving into the mechanism, ADAM22 activated the PI3K/Akt signaling pathway through the mediation of Rac Family Small GTPase 2 (RAC2), thereby facilitating EMT and metastasis in NPC. ConclusionsThe study provided pioneering insights that ADAM22 had the potential to act as an oncogene by promoting EMT and metastasis of NPC through the RAC2-mediated PI3K/Akt signaling pathway. Thus, ADAM22 could serve as a novel prognostic indicator in NPC.

A novel hepatocellular carcinoma-specific mTORC1-related signature for anticipating prognosis and immunotherapy.

Tumor oncogenesis, cancer metastasis, and immune evasion were substantially impacted by the mammalian target of the rapamycin complex 1 (mTORC1) pathway. However, in hepatocellular carcinoma (HCC), no mTORC1 signaling-based gene signature has ever been published. mTORC1 scores were computed employing a single sample gene set enrichment analysis based on databases including the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). The PAG1, LHFPL2, and FABP5 expression levels were obtained to construct a mTORC1 pathway-related model. In two databases, the overall survival (OS) rate was shorter for high-mTORC1 score patients compared to those with low scores. The activation of TFs in the group with high risk was enhanced, such as the HIF-1 pathway. Additionally, it was discovered that a high mTORC1 score was linked to an immune exclusion phenotype and enhanced immunosuppressive cell infiltration. Notably, it was discovered that high-mTORC1 scores patients had poorer immunotherapeutic results and might not gain benefit from immunotherapy. When compared to the low HCC metastatic cell lines, the high HCC metastatic cell lines have overexpressed levels of PAG1, LHFPL2, and FABP5 expression. The expression of PAG1, LHFPL2, and FABP5 was inhibited by the MAPK and mTORC1 pathway inhibitors. Our study identified mTORC1 score signature can aid in the development of individualized immunotherapy protocols and predict the HCC patients' prognoses.

MicroRNA-188-5p inhibits hepatocellular carcinoma proliferation and migration by targeting forkhead box N2

BackgroundThis study aimed to identify the biological functions, expression modes, and possible mechanisms underlying the relationship between metastatic human hepatocellular carcinoma (HCC) and MicroRNA-188-5p (miR-188) dysregulation using cell lines.MethodsA decrease in miR-188 was detected in low and high metastatic HCC cells compared to that in normal hepatic cells and non-invasive cell lines. Gain- and loss-of-function experiments were performed in vitro to investigate the role of miR-188 in cancer cell (Hep3B, HepG2, HLF, and LM3) proliferation and migration.ResultsmiR-188 mimic transfection inhibited the proliferation of metastatic HLF and LM3 cells but not non-invasive HepG2 and Hep3B cells; nonetheless, miR-188 suppression promoted the growth of HLF and LM3 cells. miR-188 upregulation inhibited the migratory rate and invasive capacity of HLF and LM3, rather than HepG2 and Hep3B cells, whereas transfection of a miR-188 inhibitor in HLF and LM3 cells had the opposite effects. Dual-luciferase reporter assays and bioinformatics prediction confirmed that miR-188 could directly target forkhead box N2 (FOXN2) in HLF and LM3 cells. Transfection of miR-188 mimics reduced FOXN2 levels, whereas miR-188 inhibition resulted in the opposite result, in HLF and LM3 cells. Overexpression of FOXN2 in HLF and LM3 cells abrogated miR-188 mimic-induced downregulation of proliferation, migration, and invasion. In addition, we found that miR-188 upregulation impaired tumor growth in vivo.ConclusionsIn summary, this study showed thatmiR-188 inhibits the proliferation and migration of metastatic HCC cells by targeting FOXN2.

Antitumor Effect of Iscador on Breast Cancer Cell Lines with Different Metastatic Potential

Studies were performed for the first time on the effect of Iscador Qu and Iscador M on phototoxicity, cytotoxicity, antiproliferative activity, changes in ξ-potential of cells, membrane lipid order, actin cytoskeleton organization and migration on three breast cancer lines with different metastatic potential: MCF10A (control), MCF-7 (low metastatic) and MDA-MB231 (high metastatic) cells. The tested Iscador Qu and M did not show any phototoxicity. The antiproliferative effect of Iscador species appeared to be dose-dependent and was related to the metastatic potential of the tested cell lines. A higher selectivity index was obtained for Iscador Qu and M towards the low metastatic MCF-7 cell line compared to the high metastatic MDA-MB-231. Iscador Qu demonstrated higher selectivity for both cancer cell lines compared to Iscador M. The malignant cell lines exhibited a decrease in fibril number and thickness regardless of the type of Iscador used. The strongest effect on migration potential was observed for the low metastatic cancer cell line MCF-7 after Iscador treatment. Both Iscador species induced a slight increase in the percentage of cells in early apoptosis for the low and high metastatic cell lines, MCF-7 and MDA-MB-231, unlike control cells. Changes in the zeta potential and membrane lipid order were observed for the low metastatic MCF-7 cell line in contrast to the high metastatic MDA-MB-231 cells. The presented results reveal a higher potential of Iscador as an antitumor agent for the low metastatic cancer cell line MCF-7 compared to the high metastatic one. Iscador Qu appears to be more potent compared to Iscador M, but at this point, the exact mechanism of action is still unclear and needs further investigations.

Melanoma stem cells promote metastasis via exosomal miR-1268a inactivation of autophagy

BackgroundMetastatic melanoma has a high mortality rate and poor survival. This is associated with efficient metastatic colonization, but the underlying mechanisms remain elusive. Communication between cancer stem cells (CSCs) and cancer cells plays an important role in metastatic dissemination. Whether cancer stem cells can alter the metastatic properties of non-CSC cells; and whether exosomal crosstalk can mediate such interaction, have not been demonstrated in melanoma prior to this report.ResultsThe results revealed that exosomes secreted by highly metastatic melanoma CSCs (OL-SCs) promoted the invasiveness of the low metastatic melanoma cells (OL) and accelerated metastatic progression. miR-1268a was up-regulated in cells and exosomes of OL-SCs. Moreover, OL-SCs-derived exosomal miR-1268a, upon taking up by OL cells, promoted the metastatic colonization ability of OL cells in vitro and in vivo. In addition, the pro-metastatic activity of exosomal miR-1268a is achieved through inhibition of autophagy.ConclusionOur study demonstrates that OL cells can acquire the “metastatic ability” from OL-SCs cells. OL-SCs cells achieves this goal by utilizing its exosomes to deliver functional miRNAs, such as miR-1268a, to the targeted OL cells which in turn augments metastatic colonization by inactivating the autophagy pathway in OL cells.

Hsa-miR-1248 suppressed the proliferation, invasion and migration of colorectal cancer cells via inhibiting PSMD10

BackgroundLymph node metastasis (LNM) is a critical event during the colorectal cancer (CRC) development and is indicative of poor prognosis. Identification of molecular markers of LNM may facilitate better therapeutic decision-making.MethodsSix pairs of CRC tissues and corresponding adjacent tissues [3 pairs diagnosed as pT1N0M0 (M_Low group) and 3 pairs diagnosed as pT4N2M0 (M_High group)] collected from CRC patients who underwent surgical resection were used. MicroRNA sequencing was performed to screen differential microRNAs involved in CRC LNM. The selected microRNAs were validated in CRC tissues and cell lines using qRT-PCR. The functions of candidate hsa-miR-1248 were evaluated by CCK-8, colony formation, and Transwell assay. The binding of hsa-miR-1248 with its target PSMD10 was confirmed by luciferase activity assay, and the expression of PSMD10 in tissues was detected by droplet digital polymerase chain reaction.ResultsNinety-five miRNAs were downregulated in carcinoma tissues (M_Low and M_high groups) compared with the normal group. Their expression in M_High group was significantly lower compared with M_Low group. The top 3 were hsa-miR-635, hsa-miR-1248, and hsa-miR-668-3p. After validation in tissues/cell lines, only hsa- hsa-miR-1248 was decreased in high metastatic tissues or SW620 cells compared to low metastatic tissues or SW480 cells. Hsa-miR-1248 was found to inhibit CRC cell viability, proliferation, invasion, and migration. The tumor suppressor effect of has-miR-1248 in CRC cells was attenuated or enhanced by up-regulating or down-regulating PSMD10, respectively.ConclusionHsa-miR-1248 may act as a tumor suppressor gene in CRC by targeting and inhibiting PSMD10, which provides a clue for CRC treatment.

Context dependent role of p53 during the interaction of hepatocellular carcinoma and endothelial cells.

During the progression of hepatocellular carcinoma (HCC), several angiogenic factors are overexpressed in the hepatic microenvironment, which play a critical role in governing the phenotype of the endothelial cells. Mutation in the p53 gene (TP53) is a common event in HCC that may dysregulate the angiogenic signals. However, their functional messages remain largely unexplored at the onset of metastasis. Role of p53 was studied by siRNA mediated silencing of p53 in HepG2 cells (WTp53), collecting and analyzing their conditioned medium, followed by indirect co-culture with endothelial cells (HUVECs). Gene and protein expression in HCC cells and endothelial cells was studied by RT-qPCR and western blotting respectively. β-catenin protein expression and localization were analyzed by immunocytochemistry. We have studied a cell-to-cell interaction model to investigate the crosstalk of endothelial and hepatoma cells by either knocking down p53 or by using p53 null low metastatic HCC cell line. In the absence of p53, the HCC cells influence the migration and vascular network formation of endothelial cells through paracrine signaling of VEGF. Secretory VEGF activated the VEGF receptor-2 along with the survival signaling in endothelial cells. However, the β-catenin signal is upregulated in endothelial cells only during interaction with metastatic set up irrespective of absence and presence of p53, indicating context-dependent participation of p53 during communication between hepatoma cells and endothelial cells. This study highlights that the role of p53 on cellular responses during interaction of hepatocellular carcinoma and endothelial cells is distinct to cell types and context.

In the Search for Novel, Isoflavone-Rich Functional Foods-Comparative Studies of Four Clover Species Sprouts and Their Chemopreventive Potential for Breast and Prostate Cancer.

Despite a significant amount of research, the relationship between a diet rich in isoflavones and breast and prostate cancer risk is still ambiguous. The purpose of the current study was to pre-select the potential candidate for functional foods among red, white, crimson, and Persian clover sprouts, cultured for different periods of time (up to 10 days), with respect to the isoflavone content (determined by HPLC-UV-VIS), and to verify their impact on hormone-dependent cancers in vitro. The red clover sprouts were the richest in isoflavones (up to 426.2 mg/100 g dw), whereas the lowest content was observed for the crimson clover. Each species produced isoflavones in different patterns, which refer to the germination time. Hormone-insensitive MDA-MB-231 breast cancer cells were more resistant to the tested extracts than estrogen-dependent MCF7 breast cancer cells. Regarding prostate cancer, androgen-dependent LNCap cells were most susceptible to the tested sprouts, followed by androgen-insensitive, high metastatic PC3, and low metastatic DU145 cells. The observed cytotoxic impact of the tested sprouts is not associated with isoflavone content, as confirmed by chemometric analysis. Furthermore, the sprouts tested revealed a high antioxidant potential, and were characterized by high safety for normal breast and prostate cells.

Gli1 promotes epithelial-mesenchymal transition and metastasis of non-small cell lung carcinoma by regulating snail transcriptional activity and stability.

Metastasis is crucial for the mortality of non-small cell lung carcinoma (NSCLC) patients. The epithelial–mesenchymal transition (EMT) plays a critical role in regulating tumor metastasis. Glioma-associated oncogene 1 (Gli1) is aberrantly active in a series of tumor tissues. However, the molecular regulatory relationships between Gli1 and NSCLC metastasis have not yet been identified. Herein, we reported Gli1 promoted NSCLC metastasis. High Gli1 expression was associated with poor survival of NSCLC patients. Ectopic expression of Gli1 in low metastatic A549 and NCI-H460 cells enhanced their migration, invasion abilities and facilitated EMT process, whereas knock-down of Gli1 in high metastatic NCI-H1299 and NCI-H1703 cells showed an opposite effect. Notably, Gli1 overexpression accelerated the lung and liver metastasis of NSCLC in the intravenously injected metastasis model. Further research showed that Gli1 positively regulated Snail expression by binding to its promoter and enhancing its protein stability, thereby facilitating the migration, invasion and EMT of NSCLC. In addition, administration of GANT-61, a Gli1 inhibitor, obviously suppressed the metastasis of NSCLC. Collectively, our study reveals that Gli1 is a critical regulator for NSCLC metastasis and suggests that targeting Gli1 is a prospective therapy strategy for metastatic NSCLC.

Bisphenol A exposure induces metastatic aggression in low metastatic MCF-7 cells via PGC-1α mediated mitochondrial biogenesis and epithelial-mesenchymal plasticity

AimsThe frequency of estrogen receptor alpha (ERα)-positive breast cancers and their metastatic progression is prevalent in females globally. Aberrant interaction of estrogen-like endocrine-disrupting chemicals (EDCs) is highly implicated in breast carcinogenesis. Studies have shown that single or acute exposures of weak EDCs such as bisphenol A (BPA) may not have a substantial pro-carcinogenic/metastatic effect. However, repeated exposure to EDCs is expected to strongly induce carcinogenic/metastatic progression, which remains to be studied. Main methodsLow metastatic ERα-positive human breast cancer cells (MCF-7) were exposed to nanomolar doses of BPA every 24 h (up to 200 days) to study the effect of repeated exposure on metastatic potential. Following the designated treatment of BPA, markers of epithelial-mesenchymal transition (EMT), migration and invasion, mitochondrial biogenesis, ATP levels, and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α) knockdown assays were performed. Key findingsA repeated exposure of low dose BPA induced stable epithelial-mesenchymal plasticity in MCF-7 cells to augment migration and invasion in the ERα-dependent pathway. Repeated exposures of BPA increased the levels of several mesenchymal markers such as N-cadherin, vimentin, cluster of differentiation 44 (CD44), slug, and alpha-smooth muscle actin (α-SMA), whereas reduced the level of E-cadherin drastically. BPA-induced mitochondrial biogenesis favored metastatic aggression by fulfilling bioenergetics demand via PGC-1α/NRF1/ERRα signaling. Knockdown of PGC-1α resulted in suppressing both mitochondrial biogenesis and EMT in BPA exposed MCF-7 cells. SignificanceRepeated exposures of low dose BPA may induce metastatic aggression in ERα-positive breast cancer cells via PGC-1α-mediated mitochondrial biogenesis and epithelial-mesenchymal plasticity.

Low-metastatic melanoma cells acquire enhanced metastatic capability via exosomal transfer of miR-199a-1-5p from highly metastatic melanoma cells

The mean survival of metastatic melanoma is less than 1 year. While the high mortality rate is associated with the efficient metastatic colonization of the involved organs, the underlying mechanisms remain elusive. The role of exosomes in facilitating the interactions between cancer cells and the metastatic microenvironment has received increasing attention. Previous studies on the role of exosomes in metastasis have been heavily focused on cancer cell-derived exosomes in modulating the functions of stromal cells. Whether the extravasated neighboring cancer cells at the distant organ can alter the metastatic properties of one another, a new mechanism of metastatic colonization, has not been demonstrated prior to this report. In this study, a paired M4 melanoma derivative cell lines, i.e., M14-OL and POL, that we established and characterized were employed. They exhibit high (POL cells) and low (OL cells) metastatic colonization efficiency in vivo, respectively. We show that exosomal crosstalk between metastatic cancer cells is a new mechanism that underlies cancer metastasis and heterogeneity. Low metastatic melanoma cells (OL) can acquire the “metastatic power” from highly metastatic melanoma cells (POL). POL achieves this goal by utilizing its exosomes to deliver functional miRNAs, such as miR-199a-1-5p, to the targeted OL cell which in turn inactivates cell cycle inhibitor CDKN1B and augments metastatic colonization.

Exosomal microRNA-4535 of Melanoma Stem Cells Promotes Metastasis by Inhibiting Autophagy Pathway.

High mortality rate and poor survival in melanoma are associated with efficient metastatic colonization. The underlying mechanisms remain elusive. Elucidating the role of exosomes in mediating the interactions between cancer cells and the metastatic microenvironment has been focused on cancer cell derived exosomes in modulating the functions of stromal cells. Whether cancer stem cells (CSCs) can modify the metastatic properties of non-CSC cells, and whether exosomal crosstalk plays a role have not been demonstrated prior to this report. In this study, a paired M14 melanoma derivative cell line, i.e., melanoma parental cell (MPC) and its CSC derivative cell line melanoma stem cell (MSC) were employed. We demonstrated that exosomal crosstalk betwen MSCs and non-CSC MPCs is a new mechanism that underlies melanoma metastasis. Low metastatic melanoma cells (MPCs) can acquire the "metastatic power" from highly metastatic melanoma CSCs (MSCs). We illustrated an uncharacterized microRNA, miR-4535 in mediating such exosomal crosstalk. MSCs deliver its exosomal miR-4535 to the targeted MPCs. Upon entering MPCs, miR-4535 augments metastatic colonization of MPCs by inactivating the autophagy pathway.

CCL18 promotes breast cancer progression by exosomal miR-760 activation of ARF6/Src/PI3K/Akt pathway

The small GTPase ADP-ribosylation factor 6 (ARF6) mediates chemokine (C-C motif) ligand 18 (CCL18)-induced activation of breast cancer (BC) metastasis through its downstream effector AMAP1. However, the molecular mechanisms underlying CCL18 up-regulating ARF6 remain largely unclear. Here, microRNAs (miRNAs) that target ARF6 were predicted and selected in high metastatic BC cells treated with CCL18. Next, we assessed the role of exosomal miR-760 in vitro and in vivo. We further analyzed the expression of ARF6, AMAP1, and phosphorylated (p)-AMAP1 in tumor and adjacent normal tissues. We first observed that CCL18 increased the expression of ARF6 and p-AMAP1 and activated the Src/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. ARF6 knockdown significantly impaired CCL18-induced malignant cellular behaviors and the Src/PI3K/Akt signaling pathway. Next, ARF6 was confirmed as a target gene of miR-760 in exosomes derived from CCL18-stimulated high metastatic BC cells. Moreover, recipient MCF-7 cells could effectively uptake these miR-760-rich exosomes that significantly promoted proliferation, tumor growth in vivo, migration, invasion, and chemoresistance by activating ARF6-mediated Src/PI3K/Akt signaling and the epithelial-mesenchymal transition (EMT) pathway. Together, our results support that exosomal miR-760 secreted by CCL18-stimulated high metastatic BC cells promoted the malignant behaviors in low metastatic BC cells by up-regulating the ARF6-mediated Src/PI3K/Akt signaling pathway.

Who's Who? Discrimination of Human Breast Cancer Cell Lines by Raman and FTIR Microspectroscopy.

Simple SummaryNormal-to-malignant transition in human cells is still a poorly understood process, as well as the mechanisms leading to cancer invasion and metastasis. An in-depth characterisation and understanding of the genetic and chemical variations underlying carcinogenesis and cancer progression are paramount for improving diagnosis and design better therapeutic strategies, aiming at a better prognosis for oncology patients. The present study reports the application of spectroscopic methods (micro-Raman and infrared) for identifying specific biomarkers of malignancy in several types of human breast cancer cells. The results thus obtained led to an accurate discrimination between the highly metastatic mammary tumours (triple-negative) and the less aggressive ones (non-triple negative), as well as among triple-negative subtypes.(1) Breast cancer is presently the leading cause of death in women worldwide. This study aims at identifying molecular biomarkers of cancer in human breast cancer cells, in order to differentiate highly aggressive triple-negative from non-triple-negative cancers, as well as distinct triple-negative subtypes, which is currently an unmet clinical need paramount for an improved patient care. (2) Raman and FTIR (Fourier transform infrared) microspectroscopy state-of-the-art techniques were applied, as highly sensitive, specific and non-invasive methods for probing heterogeneous biological samples such as human cells. (3) Particular biochemical features of malignancy were unveiled based on the cells’ vibrational signature, upon principal component analysis of the data. This enabled discrimination between TNBC (triple-negative breast cancer) and non-TNBC, TNBC MSL (mesenchymal stem cell-like) and TNBC BL1 (basal-like 1) and TNBC BL1 highly metastatic and low-metastatic cell lines. This specific differentiation between distinct TNBC subtypes—mesenchymal from basal-like, and basal-like 1 with high-metastatic potential from basal-like 1 with low-metastatic potential—is a pioneer result, of potential high impact in cancer diagnosis and treatment.

MiR-33b-3p Acts as a Tumor Suppressor by Targeting DOCK4 in Prostate Cancer.

Despite that androgen-deprivation therapy results in long-lasting responses, the disease inevitably progresses to metastatic castration-resistant prostate cancer. In this study, we identified miR-33b-3p as a tumor suppressor in prostate cancer. miR-33b-3p was significantly reduced in prostate cancer tissues, and the low expression of miR-33b-3p was correlated with poor overall survival of prostate cancer patients. Overexpression of miR-33b-3p inhibited both migration and invasion of highly metastatic prostate cancer cells whereas inhibition of miR-33b-3p promoted those processes in lowly metastatic cells. The in vivo results demonstrate that miR-33b-3p suppresses metastasis of tail vein inoculated prostate cancer cells to lung and lymph nodes in mice. DOCK4 was validated as the direct target of miR-33b-3p. miR-33b-3p decreased the expression of DOCK4 and restoration of DOCK4 could rescue miR-33b-3p inhibition on cell migration and invasion. Moreover, downregulation of miR-33b-3p was induced by bortezomib, the clinically used proteasome inhibitor, and overexpression of miR-33b-3p enhanced the insufficient inhibition of bortezomib on migration and invasion as well as metastasis of prostate cancer cells. In summary, our findings demonstrate that miR-33b-3p suppresses metastasis by targeting DOCK4 in prostate cancer. Our results suggest that enhancing miR-33b-3p expression may provide a promising therapeutic strategy for overcoming that proteasome inhibitor’s poor efficacy against metastatic prostate cancer.