Motility Of Human Cancer Cells Research Articles

Noise Genetics: Inferring Protein Function by Correlating Phenotype with Protein Levels and Localization in Individual Human Cells

To understand gene function, genetic analysis uses large perturbations such as gene deletion, knockdown or over-expression. Large perturbations have drawbacks: they move the cell far from its normal working point, and can thus be masked by off-target effects or compensation by other genes. Here, we offer a complementary approach, called noise genetics. We use natural cell-cell variations in protein level and localization, and correlate them to the natural variations of the phenotype of the same cells. Observing these variations is made possible by recent advances in dynamic proteomics that allow measuring proteins over time in individual living cells. Using motility of human cancer cells as a model system, and time-lapse microscopy on 566 fluorescently tagged proteins, we found 74 candidate motility genes whose level or localization strongly correlate with motility in individual cells. We recovered 30 known motility genes, and validated several novel ones by mild knockdown experiments. Noise genetics can complement standard genetics for a variety of phenotypes.

Abstract 5516: (R,R’)-4’-methoxy-1-naphthylfenoterol Inhibits GPR55 signaling and the modulation of motility in human cancer cells.

Abstract (R,R’)-4’-methoxy-1-naphthylfenoterol (MNF) promotes growth inhibition and apoptosis of human HepG2 hepatocarcinoma cells via cannabinoid receptor (CBR) activation. The synthetic CB1R inverse agonist, AM251, has been shown to block the anti-mitogenic effect of MNF in these cells; however, AM251 is also an agonist of the recently deorphanized, lipid-sensing receptor, GPR55, whose upregulation contributes to carcinogenesis. Here, we investigated the role of GPR55 in MNF signaling in human HepG2 and PANC-1 cancer cell lines in culture, with a focus on internalization of the fluorescent ligand Tocrifluor 1117 (T1117), reorganization of actin cytoskeleton, and cell motility as measured by scratch assay. Control experiments indicated that GPR55 knockdown by RNA interference markedly reduced cellular uptake of T1117, a process that was sensitive to MNF inhibition. GPR55 internalization mediated by the atypical cannabinoid O-1602 was blocked by MNF in GPR55-expressing HEK293 cells. Pretreatment of HepG2 and PANC-1 cells with MNF significantly abrogated the induction of ERK phosphorylation in response to AM251, O-1602 and fetal bovine serum, known to contain bioactive lipids. Moreover, MNF exerted a coordinated regulation of AM251 and O-1602 inducible processes, including cell motility. This study shows for the first time that MNF impairs GPR55-mediated signaling and, therefore, may have therapeutic potential for the management of cancer. This work was supported entirely by the Intramural Research Program of the NIA, NIH. Citation Format: Rajib K. Paul, Artur Wnorowski, Isabel Gonzalez-Mariscal, Ruin Moaddel, Fred E. Indig, Irving W. Wainer, Michel Bernier. (R,R’)-4’-methoxy-1-naphthylfenoterol Inhibits GPR55 signaling and the modulation of motility in human cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5516. doi:10.1158/1538-7445.AM2013-5516

STAT3 is involved in esophageal carcinogenesis through regulation of Oct-1

The transcription factor signal transducer and activator of transcription 3 (STAT3) contributes to cell proliferation, apoptosis and motility in human cancer cells. We aim to elucidate the function of STAT3 in esophageal carcinogenesis process and molecular mechanisms. We showed that hyperactivated STAT3 in esophageal carcinogenesis tissues correlated with the overexpression of octamer transcription factor-1 (Oct-1). High STAT3 phosphorylation correlated with shorter survival compared with low STAT3 phosphorylation. STAT3 and Oct-1 expression levels affected the proliferation and colony formation of Eca-109 esophageal squamous cell carcinoma cells by altering Erk and Akt activation. Nevertheless, STAT3 regulated the migration and invasion of esophageal squamous cell carcinoma cells independent of Oct-1. In conjunction with Oct-1, STAT3 inhibited apoptosis in esophageal squamous cell carcinoma cells. Constitutively activated STAT3 in normal human esophageal epithelium cells (HET-1A) elevated Oct-1 expression,and promoted proliferation and decreased apoptosis. STAT3 activated HET-1A cells to form tumors in vivo, suggesting that overactivated STAT3 is sufficient for carcinogenesis. We further confirmed the colocalization of STAT3 and Oct-1 in the nucleus and found that STAT3 regulates the transcription and expression of Oct-1 by directly targeting its promoter. Activated STAT3 also upregulated many genes associated with Oct-1. Together, our results indicate that STAT3 plays a crucial role in esophageal carcinogenesis by regulating the cell proliferation and apoptosis in conjunction with Oct-1.

Evaluation of the novel gene Rabl3 in the regulation of proliferation and motility in human cancer cells

Rab is a large subfamily of small GTPases which play an important role in multiple processes relating to cellular transportation and modulation of the cytoskeleton. Novel gene Rab-like 3 (Rabl3), which we originally reported as a new member belonging to this subfamily, may participate in other processes in human cancer cell lines based on our research. In order to investigate the function of Rabl3 and the basic mechanism which regulates cancer cell survival and motility, we constructed the Rabl3-pcDNA3.1 fusion plasmid, also, the specific siRNA against Rabl3 was used. We detected cellular viability and motility changes in Rabl3 overexpressed or si-Rabl3 transfected cancer cell lines. Overexpression of Rabl3 resulted in the enhancement of cell proliferation, inhibition of apoptosis and paclitaxel resistance in human cancer cell lines. Rabl3 also promoted cell motility activity. Next, we silenced Rabl3 in order to determine its exact physiological function. We found that processes which are associated with tumor formation and metastasis were inhibited. These included an increased incidence of apoptosis, abrogated cellular proliferation and mobility. Furthermore, western blot analysis revealed that the function of Rabl3 was closely associated with focal adhesion kinase (FAK) phosphorylation, both in HeLa and MDA-MB-231 cell lines at the sites of Tyr 397/576/577. Our results suggested that Rabl3 may be a novel oncogene which regulates the oncological behavior of human cancer cells. As a consequence, Rabl3 can be considered as a novel candidate in the control of tumorigenesis and as a new target for anti-tumor treatment.

Down-regulation of myopodin expression reduces invasion and motility of PC-3 prostate cancer cells

Enhanced motility of cancer cells by remodelling of the actin cytoskeleton is crucial in the process of cancer cell invasion and metastasis. Although several studies propose a tumor suppressor role for the actin bundling protein myopodin, it was also shown previously that overexpression of mouse myopodin promotes invasion in vitro. In the present study, the role of myopodin in human cancer cell motility and invasion was explored using RNA interference with siRNA duplexes designed to down-regulate all human myopodin isoforms currently identified. We show that down-regulation of myopodin expression in human cancer cells significantly reduces the invasive properties of these cells both in collagen type I and in Matrigel. Furthermore, the motile characteristics of cancer cells are also curbed by reduced myopodin expression whereas cell-cell contacts are reinforced. These results point to a role for myopodin as tumor activator. While these findings are at variance with the suggested tumor suppressor role for myopodin, we hypothesize that the subcellular localization of the protein is involved in its suppressor or activator function in tumorigenesis.

The coxsackie adenovirus receptor inhibits cancer cell migration

The coxsackie and adenovirus receptor (CAR) is a key factor in adenoviral cancer gene therapy. Reduced expression of CAR during progression of prostate and bladder cancer has been reported. In embryonic development and tissue differentiation, CAR is also differentially expressed. This study suggests a role of CAR expression in cell adhesion and cell motility of human cancer cells. Stable CAR-expressing clones from E-cadherin-deficient A2780 ovarian and CaSki cervical cancer cells with originally low and high CAR expression levels, respectively, were established. CAR reexpression in otherwise singularly growing A2780 parental cells resulted in formation of cell–cell contacts and aggregation in cell clusters. CAR overexpression in cell adhesion-forming CaSki cells did not result in morphological changes. Migration of the A2780 CAR clones was strongly reduced as characterized by using spread-off assays. Using migration chambers, formation of satellite colonies was reduced by 97% in CAR-expressing A2780 cell clones and by 23% in CAR-expressing CaSki cell clones. Parental A2780 and CaSki cells selected for high migratory ability by using migration chambers expressed endogenous CAR on lower levels associated with lower adenoviral transduction efficiency. Our data suggest CAR as a new inhibitory factor for cancer cell migration.