scholarly journals Expression of cell type incongruent alpha-cardiac actin 1 subunit in medulloblastoma reveals a novel mechanism for cancer cell survival and control of migration

2021 ◽  
Author(s):  
Rahul Suresh ◽  
Daniel Picard ◽  
Rita Lo ◽  
Jamie Beaulieu ◽  
Marc Remke ◽  
...  
Keyword(s):  
Western Blot ◽  
Cell Survival ◽  
Cell Lines ◽  
Colony Formation ◽  
Fiber Length ◽  
Length Distribution ◽  
Stress Fiber ◽  
Fiber Length Distribution ◽  
Cardiac Actin ◽  
Group 3

Abstract Background Alterations in actin subunit expression have been reported in multiple cancers, but have not been investigated previously in medulloblastoma. Methods Bioinformatic analysis of multiple medulloblastoma tumor databases was performed to profile ACTC1 mRNA levels. Western blot was used to verify protein expression in established medulloblastoma cell lines. Immunofluorescence microscopy was performed to assess ACTC1 localization. Stable cell lines with ACTC1 overexpression were generated and shRNA knockdown of ACTC1 was accomplished. We used PARP1 cleavage by Western blot as a marker of apoptosis and cell survival was determined by FACS viability assay and colony formation. Cell migration with overexpression or knockdown of ACTC1 was determined by the scratch assay. Stress fiber length distribution was assessed by fluorescence microscopy. Results : ACTC1 mRNA expression is highest in SHH and WNT medulloblastoma among all subgroups. ACTC1 protein was confirmed by Western blot in SHH subgroup and Group 3 subgroup cell lines with the lowest expression in Group 3 cells. Microscopy demonstrated ACTC1 co-localization with F-actin. Overexpression of ACTC1 in Group 3 cells abolished the apoptotic response to Aurora kinase B inhibition. Knockdown of ACTC1 in SHH cells and in Myc overexpressing SHH cells induced apoptosis impaired colony formation, and inhibited migration. Changes in stress fiber length distribution in medulloblastoma cells are induced by alterations in ACTC1 abundance. Conclusions Alpha-cardiac actin (ACTC1) is expressed in SHH medulloblastoma. Expression of this protein in medulloblastoma modifies stress fiber composition and functions in promoting resistance to apoptosis induced by mitotic inhibition, enhancing cell survival, and controlling migration.

Estimation of yarn strength based on critical slipping length and fiber length distribution

2017 ◽  
Vol 89 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Zhan Jiang ◽  
Chongwen Yu ◽  
Jianping Yang ◽  
Guangting Han ◽  
Mingjie Xing
Keyword(s):  
Fiber Length ◽  
Length Distribution ◽  
Probability Method ◽  
Yarn Strength ◽  
Fiber Length Distribution ◽  
Yarn Twist ◽  
Twist Multiplier ◽  
Strength Based ◽  
Breaking Mechanism ◽  
Yarn Structure

Yarn strength is composed of the total contributions made by all breaking and slipping fibers which are determined by critical slipping length lc. Though the definition of lc has been the focus of many research projects, it still remains unsolved. In this study, idealized assumptions were made on yarn structure, and lc was then estimated. At the same time, the actual contributions that breaking fibers and slipping fibers make to yarn strength were recalculated based on an idealized yarn structure, which was analyzed with the conditional probability method according to fiber length distribution. Then, yarn strength was computed by simulating random fiber arrangement in the yarn. It could be seen from calculated results that the critical slipping length declines as yarn twist multiplier increases. Meanwhile, as the twist multiplier increases, the calculated yarn strength rises to the highest point and then declines, which is in agreement with traditional spinning theory. Thus, the calculation of yarn strength based on critical slipping length could reflect the yarn breaking mechanism with a change in the yarn twist multiplier, and could be applied for further prediction of yarn strength.

Downregulation of Sulfiredoxin (Srx) Suppressed Cell Proliferation Migration and Invasion Through Inhibiting Extracellular Signal-Regulated Kinase/Nrf2 Pathway in Hepatocellular Carcinoma

2021 ◽  
Vol 11 (11) ◽  
pp. 2137-2145
Author(s):  
Xuejuan Zhu ◽  
Danqian Lu
Keyword(s):  
Cell Proliferation ◽  
Western Blot ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Colony Formation ◽  
Migration And Invasion ◽  
Related Factor ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Nrf2 Signaling Pathway

Background: Sulfiredoxin (Srx) has been identified to play important roles in the development of various cancers. However, the precise effects and underlying mechanism of Srx on the progression of HCC are far from being fully understood. Materials and Methods: The abundances of Srx in THLE-2 cell and HCC cell lines were determined by western blot and RT-qPCR. Next, SK-Hep-1 cells were transfected with shRNA-Srx or shRNA-NC and treated with TBHQ (an extracellular signal-regulated kinase (ERK) activator) for functional experiments. Then, CCK8 and colony formation assays were used to determine cell proliferation and clone-forming abilities in vitro. Cell migration and invasion were assessed via wound healing and transwell assays. The expression of MMP2, MMP9 and key members in ERK/nuclear factor E2 related factor (Nrf2) signaling pathway was detected by performing western blot analysis. Results: We reported evidence that Srx was frequently up-regulated in HCC cell lines. Srx interference constrained cell proliferation, colony formation rate, migration and invasion of SK-Hep-1 cells. Moreover, mechanistic investigations indicated that Srx interference significantly inhibited the activation of ERK/Nrf2 signaling pathway, and ERK activator TBHQ can reverse the functions of Srx interference in SK-Hep-1 cells. Conclusion: Overall, Downregulation of Srx might impede HCC progression by suppressing ERK/Nrf2 signaling pathway. Findings in the current study reported the functional involvement and molecular mechanism of Srx in HCC, suggesting that Srx might have a potential therapeutic value in HCC treatment.

Strength of short fiber reinforced polymers: Effect of fiber length distribution

2008 ◽  
Vol 29 (6) ◽  
pp. 644-648 ◽  
Author(s):  
Muratahan Aykol ◽  
Nihat Ali Isitman ◽  
Emre Firlar ◽  
Cevdet Kaynak
Keyword(s):  
Fiber Length ◽  
Length Distribution ◽  
Short Fiber ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Fiber Length Distribution

Inhibition of the Serine/Threonine Kinase Pim-1 Has Anti-Proliferative Effects In Acute Myeloid Leukemia (AML) and Sensitizes Multidrug Resistant Cells to Chemotherapy

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1832-1832
Author(s):  
Karthika Natarajan ◽  
Mehmet Burcu ◽  
Maria R. Baer
Keyword(s):  
Cell Cycle ◽  
Drug Resistance ◽  
Cell Survival ◽  
Cell Lines ◽  
Colony Formation ◽  
Multidrug Resistant ◽  
Serine Threonine Kinase ◽  
Hl60 Cells ◽  
Threonine Kinase ◽  
Resistance Protein

Abstract Abstract 1832 Poster Board I-812 The serine/threonine kinase Pim-1, encoded by a proto-oncogene originally identified as the proviral integration site in Moloney murine leukemia virus lymphomagenesis, phosphorylates and thereby increases expression of multiple cellular proteins, including the pro-apoptotic protein BAD, the cell cycle regulatory proteins p21, p27, Cdc25A and Cdc25C, the transcription factors SOCS-1, RUNX3 and c-myc and, as we recently demonstrated, the drug resistance-associated ATP-binding cassette (ABC) proteins P-glycoprotein (Pgp, ABCB1) and breast cancer resistance protein (BCRP, ABCG2). Pim-1 is synthesized in an active form by virtue of its hinge structure, and its activity is therefore regulated solely by its level of expression. Pim-1 is overexpressed downstream of FLT3 in AML cells with FLT3-ITD, but less is known about its expression and role in AML with wild-type (wt) FLT3. We studied Pim-1 expression and the effects of Pim-1 inhibition on AML cell survival, proliferation, apoptosis and chemosensitivity. Cell lines studied included HL60, K562, U937, Kasumi-1 and EOL-1 FLT3-wt cells and MV4-11 and MOLM-14 FLT3-ITD cells, as well as Pgp+ HL60/VCR and BCRP+ 8226/MR20 and parental 8226 myeloma cells as a model for BCRP-mediated drug resistance. Expression of Pim-1 and of phospho-BAD at S112, a measure of Pim-1 activity, was studied by Western blot analysis, normalized to GAPDH expression. Effects of the Pim-1 inhibitor SGI-1776 (SuperGen, Inc., Dublin, CA) on survival, cell cycle, apoptosis and colony growth were measured in WST-1 cell survival, flow cytometric cell cycle and apoptosis, and methylcellulose colony formation assays, respectively. SGI-1776 inhibits Pim-1 at a concentration of 7 +/− 1.8 nM, but is more than 90% bound to human plasma protein, so that its Pim-1 inhibitory concentration in cell culture-based assays is in μM range. Of note, SGI-1776 also inhibits FLT3 in this concentration range. Pim-1 was expressed in all cell lines studied, and expression of Pim-1 and of phopho-BAD did not differ between FLT3-ITD and FLT3-wt cells, nor between drug-resistant and parental cells. SGI-1776 decreased viable cell numbers in 96-hour WST-1 cell viability assays, with IC50's of 5 to 7 μM in FLT-wt cells, while IC50's were 20 and 65 nM, respectively, in MV4-11 and MOLM-14 FLT3-ITD cells. SGI-1776 IC50's did not differ between Pgp+ or BCRP+ cells and parental cells. In FLT3-wt cells, SGI-1776 had no effect on cell cycle at concentrations up to 5 μM, and caused apoptosis at 10 μM, while in FLT3-ITD cells, G1 arrest and apoptosis occurred at 100 nM. HL60 colony formation was completely inhibited by 5 μM SGI-1776, while MOLM-14 colony formation inhibition occurred at 500 nM. Finally, SGI-1776 sensitized multidrug resistant, but not parental, cells to multidrug resistance protein substrate, but not non-substrate, drugs. SGI-1776 at 1 μM decreased the IC50 of the Pgp substrate chemotherapy drug daunorubicin in Pgp+ HL60/VCR cells 7-fold, but had no effect on daunorubicin IC50 in HL60 cells, nor on IC50 of the non-Pgp substrate cytarabine in either cell line. SGI-1776 at 1 μM also decreased the IC50 of the BCRP substrate chemotherapy drug mitoxantrone in BCRP+ 8226/MR20 cells 7-fold. SGI-1776 at 1 μM doubled the percentage of apoptotic cells among HL60/VCR, but not HL60, cells exposed to daunorubicin and 8226/MR20 cells exposed to mitoxantrone. Finally, SGI-1776 at 1 μM decreased HL60/VCR colony formation in the presence of daunorubicin, but not cytarabine, but had no effect in HL60 cells, and also decreased 8226/MR20 colony formation in the presence of mitoxantrone, but not cytarabine. Thus the Pim-1 inhibitor SGI-1776 has anti-proliferative effects in AML cells with wt FLT3 as well FLT3-ITD, and sensitizes Pgp+ and BCRP+ multidrug resistant cells to chemotherapy. These data support clinical trials of SGI-1776 in AML with wt FLT3 as well FLT3-ITD, as a single agent and in combination with chemotherapy in multidrug resistant AML. Disclosures: No relevant conflicts of interest to declare.

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