p125 focal adhesion kinase promotes malignant astrocytoma cell proliferation in vivo

2000 ◽  
Vol 113 (23) ◽  
pp. 4221-4230 ◽  
Author(s):  
D. Wang ◽  
J.R. Grammer ◽  
C.S. Cobbs ◽  
J.E. Stewart ◽  
Z. Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Focal Adhesion ◽  
Fold Increase ◽  
Astrocytic Tumor ◽  
Malignant Astrocytoma

p125 focal adhesion kinase (p125FAK) is a cytoplasmic tyrosine kinase that is activated upon engagement of integrin cell adhesion receptors, and initiates several signaling events that modulate cell function in vitro. To determine the biologic role of p125FAK in malignant astrocytic tumor cells, U-251MG human malignant astrocytoma cells were stably transfected with p125FAK cDNA using the TET-ON system, and stable clones isolated that exhibited an estimated 5- or 20-fold increase in p125FAK expression on administration of 0.1 or 2.0 microg/ml doxycycline, respectively. In vitro studies demonstrated that induction of p125FAK resulted in a 2- to 3-fold increase in cell migration, increased p130CAS phosphorylation, localization of exogenous p125FAK to focal adhesions, and a 2-fold increase in soft agar growth. To determine the role of p125FAK in vivo, clones were injected stereotactically into the brains of scid mice. A 4.5-fold estimated increase in p125FAK expression was induced by administration of doxycycline in the drinking water. Analysis of xenograft brains demonstrated that, upon induction of p125FAK, there was a 1.6- to 2.8-fold increase in tumor cell number, and an increase in mAb PCNA-labeling of tumor cells in the absence of a change in the apoptotic index. Compared to normal brain, the expression of p125FAK was elevated in malignant astrocytic tumor biopsies from patient samples. These data demonstrate for the first time that p125FAK promotes tumor cell proliferation in vivo, and that the underlying mechanism is not associated with a reduction in apoptosis.

scholarly journals Tumor quiescence: elevating SOX2 in diverse tumor cell types downregulates a broad spectrum of the cell cycle machinery and inhibits tumor growth

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ethan P. Metz ◽  
Erin L. Wuebben ◽  
Phillip J. Wilder ◽  
Jesse L. Cox ◽  
Kaustubh Datta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cell Cycle Machinery

Abstract Background Quiescent tumor cells pose a major clinical challenge due to their ability to resist conventional chemotherapies and to drive tumor recurrence. Understanding the molecular mechanisms that promote quiescence of tumor cells could help identify therapies to eliminate these cells. Significantly, recent studies have determined that the function of SOX2 in cancer cells is highly dose dependent. Specifically, SOX2 levels in tumor cells are optimized to promote tumor growth: knocking down or elevating SOX2 inhibits proliferation. Furthermore, recent studies have shown that quiescent tumor cells express higher levels of SOX2 compared to adjacent proliferating cells. Currently, the mechanisms through which elevated levels of SOX2 restrict tumor cell proliferation have not been characterized. Methods To understand how elevated levels of SOX2 restrict the proliferation of tumor cells, we engineered diverse types of tumor cells for inducible overexpression of SOX2. Using these cells, we examined the effects of elevating SOX2 on their proliferation, both in vitro and in vivo. In addition, we examined how elevating SOX2 influences their expression of cyclins, cyclin-dependent kinases (CDKs), and p27Kip1. Results Elevating SOX2 in diverse tumor cell types led to growth inhibition in vitro. Significantly, elevating SOX2 in vivo in pancreatic ductal adenocarcinoma, medulloblastoma, and prostate cancer cells induced a reversible state of tumor growth arrest. In all three tumor types, elevation of SOX2 in vivo quickly halted tumor growth. Remarkably, tumor growth resumed rapidly when SOX2 returned to endogenous levels. We also determined that elevation of SOX2 in six tumor cell lines decreased the levels of cyclins and CDKs that control each phase of the cell cycle, while upregulating p27Kip1. Conclusions Our findings indicate that elevating SOX2 above endogenous levels in a diverse set of tumor cell types leads to growth inhibition both in vitro and in vivo. Moreover, our findings indicate that SOX2 can function as a master regulator by controlling the expression of a broad spectrum of cell cycle machinery. Importantly, our SOX2-inducible tumor studies provide a novel model system for investigating the molecular mechanisms by which elevated levels of SOX2 restrict cell proliferation and tumor growth.

Protease Activated Receptor-1 (PAR-1) Impedes Tumor Progression

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2560-2560
Author(s):  
Gregory N. Adams ◽  
Haley Weston ◽  
Leah Rosenfeldt ◽  
Malinda Frederick ◽  
Joseph S. Palumbo
Keyword(s):  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Prostate Tumor ◽  
Protease Activated Receptor 1 ◽  
Tumor Types ◽  
And Control

Abstract Activation of cell signaling by thrombin through Protease Activated Receptor-1 (PAR-1) represents one important interface between blood coagulation and cell activation in response to injury and inflammation. In the context of cancer, PAR-1 has been suggested to promote tumor growth through mechanisms coupled to tumor cell proliferation, tumor cell migration, and the development of a supportive tumor stroma. Consistent with this view, both tumor cells and stromal cells express high levels of PAR-1, and elevated PAR-1 expression has been correlated with a poor prognosis across several tumor types. In the current studies, we tested the hypothesis that PAR-1 is a critical driver of tumorigenesis and tumor growth using murine models of genetically-induced prostate and intestinal tumor growth. To define the role of PAR-1 in prostate tumor progression, we interbred mice expressing the TRAMP transgene (transgenic adenocarcinoma of the mouse prostate; SV40 Large T antigen under the control of a probasin promoter) to PAR-1-deficient mice (PAR-1-/-) in order to generate male TRAMP mice with and without PAR-1 expression for detailed analyses of prostate tumor growth. Surprisingly, prostate tumors harvested from PAR-1-/- mice were significantly larger than those harvested from PAR-1+/+ mice. In order to begin to address the PAR-1 expressing cellular compartments responsible for prostate tumor inhibition, we subcutaneously inoculated immunocompetent C57Bl/6-derived PAR-1-/- and control mice with tumor cells derived from a C57Bl/6 TRAMP mouse. TRAMP-derived tumors grew indistinguishably in PAR-1-/- and control mice, suggesting that stromal-cell associated PAR-1 is dispensable for prostate tumor growth. We next tested the effect of tumor cell-intrinsic inhibition of PAR-1 in TRAMP tumor cells by viral transduction with a construct containing an shRNA against murine PAR-1 in parallel to a non-specific shRNA construct. Diminishing tumor cell-associated PAR-1 expression resulted in significantly more rapid tumor growth in vivo. In order to better define the role of tumor cell-intrinsic PAR-1 we harvested TRAMP tumor cells from a PAR-1 deficient mouse and grew these cells in vitro. We transduced these PAR-1-deficient prostate tumor cells with viral vectors conferring expression of WT murine PAR-1 (PAR-1+), a PAR-1 mutant lacking the thrombin cleavage (R41A mutant) or empty vector (PAR-1-). PAR-1- cells grew robustly and similarly to the parental cells in vitro with a doubling time of approximately 48 hours. Cells expressing the R41A mutant PAR-1 also grew robustly and similarly to PAR-1 deficient cells. However, PAR-1+ cells failed to show any signs of cell proliferation over the span of a 4 day observation period. Furthermore, PAR-1 expression dramatically altered the ability of TRAMP cells to demonstrate signs of cell spreading as measured by the frequency of pseudopodia per cell. As a means of determining the role of PAR-1 in tumorigenesis and tumor growth in another spontaneously occurring setting, we interbred PAR-1-/- mice with APCMin/+ mice genetically predisposed to intestinal adenoma formation due to loss of heterozygosity of the tumor suppressor adenomatous polyposis coli gene. Blinded quantitative histological analyses of the intestinal tracts of PAR-1-/- and PAR-1+/+ APCMin/+ mice revealed that PAR-1 deficiency resulted in a significant 2-fold increase in the number of adenomas observed. Furthermore, the adenomas observed in PAR-1-/- mice were significantly larger based on morphometric analyses of adenoma surface area in histological sections. In sum, these data demonstrate a surprising and unexpected role for PAR-1 in the inhibition of tumor growth in the context of two distinct tumor types. Disclosures No relevant conflicts of interest to declare.

scholarly journals Tumor cell-intrinsic PD-1 receptor is a tumor suppressor and mediates resistance to PD-1 blockade therapy

2020 ◽  
Vol 117 (12) ◽  
pp. 6640-6650 ◽  
Author(s):  
Xiaodong Wang ◽  
Xiaohui Yang ◽  
Chang Zhang ◽  
Yang Wang ◽  
Tianyou Cheng ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Suppressor ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Colony Formation ◽  
Immune Escape ◽  
Potential Biomarker

The programmed cell death 1 (PD-1) receptor on the surface of immune cells is an immune checkpoint molecule that mediates the immune escape of tumor cells. Consequently, antibodies targeting PD-1 have shown efficacy in enhancing the antitumor activity of T cells in some types of cancers. However, the potential effects of PD-1 on tumor cells remain largely unknown. Here, we show that PD-1 is expressed across a broad range of tumor cells. The silencing of PD-1 or its ligand, PD-1 ligand 1 (PD-L1), promotes cell proliferation and colony formation in vitro and tumor growth in vivo. Conversely, overexpression of PD-1 or PD-L1 inhibits tumor cell proliferation and colony formation. Moreover, blocking antibodies targeting PD-1 or PD-L1 promote tumor growth in cell cultures and xenografts. Mechanistically, the coordination of PD-1 and PD-L1 activates its major downstream signaling pathways including the AKT and ERK1/2 pathways, thus enhancing tumor cell growth. This study demonstrates that PD-1/PD-L1 is a potential tumor suppressor and potentially regulates the response to anti-PD-1/PD-L1 treatments, thus representing a potential biomarker for the optimal cancer immunotherapeutic treatment.

scholarly journals α1-Adrenergic Receptor Antagonists: Novel Therapy for Pituitary Adenomas

2005 ◽  
Vol 19 (12) ◽  
pp. 3085-3096 ◽  
Author(s):  
Manory A. Fernando ◽  
Anthony P. Heaney
Keyword(s):  
Cell Proliferation ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Pituitary Tumor ◽  
Adrenergic Receptor ◽  
Pituitary Tumors ◽  
Nuclear Factor Κb ◽  
Nuclear Factor

Abstract Pituitary tumors are common and cause considerable morbidity due to local invasion and altered hormone secretion. Doxazosin (dox), a selective α1-adrenergic receptor antagonist, used to treat hypertension, also inhibits prostate cancer cell proliferation. We examined the effects of dox on murine and human pituitary tumor cell proliferation in vitro and in vivo. dox treatment inhibited proliferation of murine pituitary tumor cells, induced G0-G1 cell cycle arrest, and reduced phosphorylated retinoblastoma levels. In addition, increased annexin-fluorescein isothiocyanate immunoreactivity and cleaved caspase-3 levels, in keeping with dox-mediated apoptosis, were observed in the human and murine pituitary tumor cells, and dox administration to mice, harboring corticotroph tumors, decreased tumor growth and reduced plasma ACTH levels. dox-mediated antiproliferative and proapoptotic actions were not confined to α-adrenergic receptor-expressing pituitary tumor cells and were unaffected by cotreatment with the α-adrenergic receptor blocker, phenoxybenzamine. dox treatment led to reduced phosphorylated inhibitory κB (IκB)-α expression, and nuclear factor-κB transcription and decreased basal and TNFα-induced proopiomelanocortin transcriptional activation. These results demonstrate that the selective α1-adrenergic receptor antagonist dox inhibits pituitary tumor cell growth in vitro and in vivo by mechanisms that are in part independent of its α-adrenergic receptor-blocking actions and involve down-regulation of nuclear factor-κB signaling. dox is proposed as a possible novel medical therapy for pituitary tumors.

scholarly journals Depleting RhoA/Stress Fiber-Organized Fibronectin Matrices on Tumor Cells Non-Autonomously Aggravates Fibroblast-Driven Tumor Cell Growth

2020 ◽  
Vol 21 (21) ◽  
pp. 8272
Author(s):  
Li-Tzu Huang ◽  
Chen-Lung Tsai ◽  
Shin-Huei Huang ◽  
Ming-Min Chang ◽  
Wen-Tsan Chang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Stress Fiber ◽  
Tumor Cell Growth ◽  
Primary Tumor Growth

Fibronectin (FN) expressed by tumor cells has been known to be tumor suppressive but the pericellular FN (periFN) assembled on circulating tumor cells appears to evidently promote distant metastasis. Whereas the regulation of periFN assembly in suspended cells has currently been under investigation, how it is regulated in adherent tumor cells and the role of periFN in primary tumor growth remain elusive. Techniques of RNAi, plasmid transfections, immunoblotting, fluorescence/immunohistochemistry staining, cell proliferation assays, and primary tumor growth in C57BL6 mice and Fischer 344 rats were employed in this study. We found that endogenously synthesized FN in adherent tumor cells was required for periFN assembly which was aligned by RhoA-organized actin stress fiber (SF). Depleting periFN on adherent tumor cells congruently promoted in vivo tumor growth but surprisingly did not autonomously impact on in vitro tumor cell proliferation and apoptosis, suggestive of a non-autonomous role of periFN in in vivo tumor growth. We showed that the proliferative ability of shFN-expressing tumor cells was higher than shScramble cells did in the presence of fibroblasts. Altogether, these results suggested that depriving RhoA/SF-regulated periFN matrices non-autonomously promotes fibroblast-mediated tumor cell growth.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

scholarly journals KLF7/VPS35 axis contributes to hepatocellular carcinoma progression through CCDC85C-activated β-catenin pathway

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yarong Guo ◽  
Bao Chai ◽  
Junmei Jia ◽  
Mudan Yang ◽  
Yanjun Li ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Luciferase Reporter ◽  
Aberrant Expression ◽  
Proliferation And Invasion ◽  
Hcc Cells

Abstract Objective Dysregulation of KLF7 participates in the development of various cancers, but it is unclear whether there is a link between HCC and aberrant expression of KLF7. The aim of this study was to investigate the role of KLF7 in proliferation and migration of hepatocellular carcinoma (HCC) cells. Methods CCK8, colony growth, transwell, cell cycle analysis and apoptosis detection were performed to explore the effect of KLF7, VPS35 and Ccdc85c on cell function in vitro. Xenografted tumor growth was used to assess in vivo role of KLF7. Chip-qPCR and luciferase reporter assays were applied to check whether KLF7 regulated VPS35 at transcriptional manner. Co-IP assay was performed to detect the interaction between VPS35 and Ccdc85c. Immunohistochemical staining and qRT-PCR analysis were performed in human HCC sampels to study the clinical significance of KLF7, VPS35 and β-catenin. Results Firstly, KLF7 was highly expressed in human HCC samples and correlated with patients’ differentiation and metastasis status. KLF7 overexpression contributed to cell proliferation and invasion of HCC cells in vitro and in vivo. KLF7 transcriptional activation of VPS35 was necessary for HCC tumor growth and metastasis. Further, co-IP studies revealed that VPS35 could interact with Ccdc85c in HCC cells. Rescue assay confirmed that overexpression of VPS35 and knockdown of Ccdc85c abolished the VPS35-medicated promotion effect on cell proliferation and invasion. Finally, KLF7/VPS35 axis regulated Ccdc85c, which involved in activation of β-catenin signaling pathway, confirmed using β-catenin inhibitor, GK974. Functional studies suggested that downregulation of Ccdc85c partly reversed the capacity of cell proliferation and invasion in HCC cells, which was regulated by VPS35 upregulation. Lastly, there was a positive correlation among KLF7, VPS35 and active-β-catenin in human HCC patients. Conclusion We demonstrated that KLF7/VPS35 axis promoted HCC cell progression by activating Ccdc85c-medicated β-catenin pathway. Targeting this signal axis might be a potential treatment strategy for HCC.

scholarly journals The human vault RNA enhances tumorigenesis and chemoresistance through the lysosome

2020 ◽  
Author(s):  
Iolanda Ferro ◽  
Jacopo Gavini ◽  
Lisamaria Bracher ◽  
Marc Landolfo ◽  
Daniel Candinas ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Cell ◽  
Chemotherapy Resistance ◽  
Autophagic Flux ◽  
Tumor Cell Proliferation ◽  
Apoptosis Resistance ◽  
Knock Out ◽  
Vault Rna

AbstractThe small non-coding vault RNA (vtRNA) 1-1 has been shown to confer apoptosis resistance in several malignant cell lines and also to modulate the autophagic flux in hepatocytes, thus highlighting its pro-survival role. Here we describe a new function of vtRNA1-1 in regulating in vitro and in vivo tumor cell proliferation, tumorigenesis and chemoresistance. By activating extracellular signal-regulated kinases (ERK 1/2), vtRNA1-1 knock-out (KO) inhibits transcription factor EB (TFEB), leading to a downregulation of the coordinated lysosomal expression and regulation (CLEAR) network genes and lysosomal compartment dysfunction. Pro-tumorigenic pathways dysregulation and decreased lysosome functionality potentiate the anticancer effect of conventional targeted cancer drugs in the absence of vtRNA1-1. Finally, vtRNA1-1 KO-reduced lysosomotropism, together with a higher intracellular compound availability, significantly reduced tumor cell proliferation in vitro and in vivo. These findings reveal the role of vtRNA1-1 in ensuring intracellular catabolic compartment stability and functionality, suggesting its importance in lysosome-mediated chemotherapy resistance.

scholarly journals circATP2A2 promotes osteosarcoma progression by upregulating MYH9

Open Medicine ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1749-1761
Author(s):  
Xin Cao ◽  
Xianfeng Meng ◽  
Peng Fu ◽  
Lin Wu ◽  
Zhen Yang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Area Under Curve ◽  
Prognostic Biomarker ◽  
Migration And Invasion ◽  
Promising Target ◽  
Repressive Effect ◽  
Cell Malignancy

Abstract Osteosarcoma (OS) is a highly metastatic primary malignant tumor. CircRNA hsa_circ_0028173 (circATP2A2) has been uncovered to be related to the advancement of OS. However, the biological role of circATP2A2 in OS has not been validated. circATP2A2 and MYH9 were upregulated while miR-335-5p was downregulated in OS. OS patients with high circATP2A2 expression displayed a shorter overall survival and the area under curve of circATP2A2 was 0.77, manifesting that circATP2A2 might be a diagnostic and prognostic biomarker. circATP2A2 silencing repressed OS cell proliferation and glycolysis in vivo and constrained OS cell proliferation, glycolysis, migration, and invasion in vitro. circATP2A2 regulated MYH9 expression through sponging miR-335-5p. MiR-335-5p inhibitor reversed the repressive effect of circATP2A2 knockdown on OS cell malignancy and glycolysis. MYH9 overexpression overturned miR-335-5p upregulation-mediated OS cell malignancy and glycolysis. circATP2A2 accelerated OS cell malignancy and glycolysis through upregulating MYH9 via sponging miR-335-5p, offering a promising target for OS treatment.

scholarly journals HNRNPA2B1 promotes multiple myeloma progression by increasing AKT3 expression via m6A-dependent stabilization of ILF3 mRNA

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fengjie Jiang ◽  
Xiaozhu Tang ◽  
Chao Tang ◽  
Zhen Hua ◽  
Mengying Ke ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Aberrant Expression ◽  
The Stability ◽  
Induced Apoptosis ◽  
Proliferation In Vitro

AbstractN6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic RNAs while accumulating studies suggest that m6A aberrant expression plays an important role in cancer. HNRNPA2B1 is a m6A reader which binds to nascent RNA and thus affects a perplexing array of RNA metabolism exquisitely. Despite unveiled facets that HNRNPA2B1 is deregulated in several tumors and facilitates tumor growth, a clear role of HNRNPA2B1 in multiple myeloma (MM) remains elusive. Herein, we analyzed the function and the regulatory mechanism of HNRNPA2B1 in MM. We found that HNRNPA2B1 was elevated in MM patients and negatively correlated with favorable prognosis. The depletion of HNRNPA2B1 in MM cells inhibited cell proliferation and induced apoptosis. On the contrary, the overexpression of HNRNPA2B1 promoted cell proliferation in vitro and in vivo. Mechanistic studies revealed that HNRNPA2B1 recognized the m6A sites of ILF3 and enhanced the stability of ILF3 mRNA transcripts, while AKT3 downregulation by siRNA abrogated the cellular proliferation induced by HNRNPA2B1 overexpression. Additionally, the expression of HNRNPA2B1, ILF3 and AKT3 was positively associated with each other in MM tissues tested by immunohistochemistry. In summary, our study highlights that HNRNPA2B1 potentially acts as a therapeutic target of MM through regulating AKT3 expression mediated by ILF3-dependent pattern.

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