scholarly journals HB9 Represses Hematopoietic Stem Cell Proliferation and Induces Senescence

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1539-1539
Author(s):  
Deborah Ingenhag ◽  
Franziska Auer ◽  
Arndt Borkhardt ◽  
Julia Hauer
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Line ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Oncogenic Potential ◽  
Stem Cell Proliferation ◽  
Senescent Phenotype

Abstract Introduction: HB9 is a transcription factor encoded by homeobox gene B9 (HLXB9). It is physiologically expressed during early embryonic development as well as in pancreatic beta- and motor neuronal cell development. Ectopic HB9 expression is found in infant acute myeloid leukemia with translocation t(7;12), accounting for up to one third of infant AML cases with a poor 3-year EFS of 0% irrespective of the treatment approach. We previously showed that HB9 regulates cell-cell interaction/adhesion (Wildenhain et al. Leukemia, 2010) in hematopoietic cells and influences the prostaglandin signalling pathway (Wildenhain & Ingenhag et al. JBC, 2012). In this study we focussed on the oncogenic potential of HB9 in hematopoiesis. Methods: To investigate the oncogenic influence of HB9 expression on hematopoiesis, we developed an in vivo murine transplantation model. HB9-transduced lineage negative (Lin-) murine HSCs were transplanted into lethally irradiated wild-type mice and we monitored hematopoietic reconstitution and leukemia emergence by serial retroorbital bleedings for up to one year. Final analysis included comprehensive flow cytometric analysis of all hematopoietic compartments, with respect to dissemination of blast cells and cellular distribution. In vitro studies included proliferation as well as cell cycle analysis. Senescent phenotype was characterized by senescence-associated beta-galactosidase staining and cellular morphology. Knockdown of p53 was obtained via transfection of siRNA. Results: Transplantation of HB9- or mock-transduced murine Lin- cells into lethally irradiated wild-type recipient mice (n=10) showed >80% donor chimerism and HB9-transduced Lin- cells gave rise to all hematopoietic lineages (B-lineage: CD19+, T-lineage: CD3+, NK-lineage: Nk1.1+, granulocytic lineage: Gr-1+, Monocytic lineage: CD11b+) in the peripheral blood, indicating no lineage-related preference of HB9-expressing HSCs. Reconstitution of peripheral blood cell compartments in HB9 transplanted mice, however, was significantly decreased in all three lineages (CD3+: 9.5-fold, CD19+: 34.7-fold , Gr+: 1.8-fold) compared to the control group with respect to copy number, mRNA and protein expression. We did not observe an accumulation of hematopoietic stem (LT-HSC, ST-HSC, MPP) and precursor cells subsets (CLP, MEP, CMP, GMP) in the bone marrow of mice transplanted with HB9-positive Lin- cells. Finally, mice transplanted with HB9-transduced Lin- cells did not develop leukemia after 12 months follow-up. The decreased reconstitution capacity of HB9 expressing HSCs led us to the assumption that HB9 represses cellular proliferation in vivo. Thus we performed proliferation studies in vitro. Ectopic expression of HB9 in the murine NIH3T3 cell line revealed a complete inhibition of cell proliferation compared to mock control (n=3). The same effect was observed in human HT1080 cell line. Cell cycle analysis revealed a significant decrease of the S-phase (2-fold, p<0.05), stalling the cells in G1 and G2 phase of the cell cycle. In both cell line models HB9-transduced cells developed a senescent phenotype being multinuclear, flattened and enlarged. Staining for senescence-associated β-galactosidase activity was positive in HB9-transduced cells in contrast to complete absence in mock-transduced cells. Immunoblot analysis revealed that the HB9 dependent cell cycle arrest was mediated via p53-induced upregulation of p21. Knockdown experiments using p53-targeting siRNAs confirmed that the p53-signalling is responsible for the growth arrest because p53-knockdown was able to reverse the effect. Conclusion:In our study HB9 represses hematopoietic stem cell proliferation in vivo and induces a senescent phenotype in vitro. Senescence is an evasion mechanism in response to aberrant oncogene expression and induction of senescence is the first evidence for an oncogenic potential of HB9. Future studies elucidating the signal pattern of HB9-induced senescence will shed new light on the pathomechanism and potential therapeutic targets in the treatment of translocation t(7;12) positive AML. Disclosures No relevant conflicts of interest to declare.

PI3K/Akt/FOXO3a Pathway Contributes to Thrombopoietin-Induced Proliferation of Primary Megakaryocytes In Vitro and In Vivo Via Modulation of p27Kip1.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 202-202
Author(s):  
Takafumi Nakao ◽  
Amy E Geddis ◽  
Norma E. Fox ◽  
Kenneth Kaushansky
Keyword(s):  
Cell Cycle ◽  
Cell Line ◽  
Cell Cycle Progression ◽  
Wild Type ◽  
Cycle Progression ◽  
P27kip1 Expression ◽  
Cell Counts ◽  
Deficient Mice

Abstract Thrombopoietin (TPO), the primary regulator of megakaryocyte (MK) and platelet formation, modulates the activity of multiple signal transduction molecules, including those in the Jak/STAT, p42/p44 MAPK, and phosphatidylinositol 3-kinase (PI3K)/Akt pathways. In the previous study, we reported that PI3K and Akt are necessary for TPO-induced cell cycle progression of primary MK progenitors. The absence of PI3K activity results in a block of transition from G1 to S phase in these cells (Geddis AE et al. JBC2001276:34473–34479). However, the molecular events secondary to the activation of PI3K/Akt responsible for MK proliferation remain unclear. In this study we show that FOXO3a and its downstream target p27Kip1 play an important role in TPO-induced proliferation of MK progenitors. TPO induces phosphorylation of Akt and FOXO3a in both UT-7/TPO, a megakaryocytic cell line, and primary murine MKs in a PI3K dependent fashion. Cell cycle progression of UT-7/TPO cells is blocked in G1 phase by inhibition of PI3K. We found that TPO down-modulates p27Kip1 expression at both the mRNA and protein levels in UT-7/TPO cells and primary MKs in a PI3K dependent fashion. UT-7/TPO stably expressing constitutively active Akt or a dominant-negative form of FOXO3a failed to induce p27Kip1 expression after TPO withdrawal. Induced expression of an active form of FOXO3a resulted in increased p27Kip1 expression in this cell line. In an attempt to assess whether FOXO3a has an effect of MK proliferation in vivo, we compared the number of MKs in Foxo3a-deficient mice and in wild type controls. Although peripheral blood cell counts of erythrocytes, neutrophils, monocytes and platelets were normal in the Foxo3a-deficient mice, total nucleated marrow cell count of Foxo3a-deficient mice were 60% increased compared with wild type controls. In addition, the increase of MKs was more profound than that of total nucleated marrow cells; CD41+ MKs from Foxo3a-deficient mice increased 2.1-fold, and mature MKs with 8N and greater ploidy increased 2.5-fold, compared with wild type controls. Taken together with the previous observation that p27Kip1-deficient mice also display increased numbers of MK progenitors, our findings strongly suggest that the effect of TPO on MK proliferation is mediated by PI3K/Akt-induced FOXO3a inactivation and subsequent p27Kip1 down-regulation in vitro and in vivo.

Excessive Hematopoietic Stem Cell Proliferation Leads to Chromosomal Instability

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4772-4772
Author(s):  
Liliana Souza ◽  
Natalyn Hawk ◽  
Sweta Sengupta ◽  
Carlos Cabrera ◽  
Morgan L. McLemore
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Chromosomal Instability ◽  
Wild Type ◽  
Dna Breaks ◽  
Hematopoietic Stem ◽  
Stem Cell Proliferation ◽  
Double Stranded Dna

Abstract Truncation mutations in the granulocyte colony stimulating factor receptor (G-CSFR), common in severe congenital neutropenia (SCN), lead to excessive stem cell proliferation in response to G-CSF. These G-CSFR mutants are (at least indirectly) implicated in the progression of these patients to acute leukemia. Since SCN patients require continuous G-CSF treatment throughout their lifespan, we hypothesize that excessive stem cell proliferation can lead to DNA damage. Stem cells are relatively quiescent and rarely enter the cell cycle under normal conditions. During the cell cycle cells generate approximately 5000 single strand DNA lesions per nucleus (Vilenchik and Knudson, 2003). Approximately 1% of these lesions are ultimately converted to double strand DNA breaks (DSBs). Hematopoietic stem cells are found within the Sca+ ckit+ Lin- (KLS) population. Wild type and mice bearing a mutant G-CSFR similar to that found in patients with SCN were treated with G-CSF. After 21 days of treatment with G-CSF (10 ug/kg/day), the KLS population in the bone marrow increased four-fold in wild type mice and eight-fold in mutant mice. We isolated Lin-Sca+ bone marrow cells from these G-CSF treated mice and evaluated for the presence of double stranded DNA breaks by staining with anti-phospho-H2AX by immunofluorescence. H2AX is a histone whose phosphorylated form localizes to the site of double stranded DNA breaks. The results showed that there is an 8-fold increase in the DSB in wild type Lin-Sca+ and 10-fold in mutant Lin-Sca+ when compared to cells from untreated mice. This data suggests that excessive proliferation can contribute to an increase in DSBs in hematopoietic stem cells. Investigation of potential mechanisms contributing to DSB formation are ongoing. Understanding the causes and trends of chromosomal instability would improve our understanding of leukemogenesis and potentially reveal novel treatment strategies.

The ETS Transcription Factor ETV7 Exhausts Hematopoietic Stem Cells By Enhancing The Cell Cycle Entry and Cell Proliferation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 733-733 ◽  
Author(s):  
Masashi Numata ◽  
Ramon Klein Geltink ◽  
Gerard Grosveld
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Suppressor ◽  
Brdu Incorporation ◽  
Post Transplantation ◽  
Hematopoietic Stem ◽  
Cell Cycle Entry ◽  
Fcm Analysis

Abstract Although ETS-transcription factors play a role in normal and malignant hematopoiesis, their function in hematopoietic stem cells (HSCs) and leukemia initiating cells (LICs) is largely unknown. We originally identified the novel ETS transcription factor ETV7, which is highly homologous to ETV6/TEL, a frequent target of chromosomal translocation in human leukemia. Previously we have shown that ETV7 is a hematopoietic oncoprotein that requires cooperating mutations to induce leukemic transformation. Microarray analysis revealed that ETV7 expression is upregulated in 70% of pediatric ALL and AML samples. This indicates a possible oncogenic function of ETV7 in a variety of leukemias, although the molecular mechanism of ETV7-mediated leukemogenesis remains to be elucidated. ETV7 is widely but not abundantly expressed in various human tissues. Recently we found that overexpression of ETV7 in human cord blood-derived CD34+ cells depletes the number of CD34+CD38- HSCs. In addition, ETV7-transduced cells slightly accerelated cell proliferation. These results suggest that overexpression of ETV7 activates cell proliferation in primary human CD34+cells and depletes the number of HSCs. Here, by using a mouse model, we show that ectopic expression of ETV7 in quiescent HSCs accelerates their cell cycle entry and proliferation, leading to the exhaust of HSCs in mice. The ETV7 gene locus is deleted in part of the rodents including the mouse despite its high level of conservation among vertebrates. To circumvent this limitation, we have generated an ETV7 BAC transgenic mouse that carries a single copy of a human BAC DNA containing the ETV7 gene locus. In flow cytometry (FCM) analysis of wild type (WT) and ETV7 bone marrow (BM)-derived Lin-Sca1+cKit+(LSK) cells, the size and frequency of LT(long term)-HSCs (CD48-CD150+LSK) in ETV7 LSK was 2-fold lower than that in WT LSK, while the frequency of LSK and hematopoietic common progenitor cells in WT and ETV7 BM are similar. As compared with WT-LSK, ETV7-LSK showed a significantly decreased number of myeloid progenitor colonies in both the initial plating (MC1) and replating of MC1 colonies (MC2) in methylcellulose colony formation assay in vitro. To assess the ETV7 HSC function contributing to blood cell generation in vivo, we performed competitive repopulation assays. In agreement with the in vitro results, the repopulation ability of HSC is significantly compromised in ETV7 mice as measured 7 weeks post transplantation. This defect was even more pronounced 16 weeks post transplantation. Since enhanced cell cycle entry is known to cause loss of hematopoietic stem/progenitor cells (HSPCs) through the activation of a tumor suppressor response, we quantified p19ARF, p16INK4a, and p21CDKN1A gene expression in LSK cells by qRT-PCR. At day 6 and day 9 of in vitro culture, ETV7 LSK cells activated the p19ARF, p16INK4a, and p21CDKN1A genes about 2-fold greater than WT LSK cells. To measure the de novo DNA replication of HSPCs in vivo, BrdU-pulse labeled BM cells were harvested and BrdU incorporation was quantified by FCM analysis. ETV7 LSK cells showed elevated BrdU incorporation compared with that of WT. In addition, Hoechst33342/Pyronin Y staining revealed that ETV7 LSK enhanced transition from G0 to the G1 phase of the cell cycle, suggesting that ETV7 forced cell cycle entry of quiescent HSCs. Finally to clarify the involvement of the CDKN2A tumor suppressor in ETV7-associated HSC exhaustion, we examined the frequency of HSPCs in CDKN2A-/- and ETV7+/-CDKN2A-/- LSK cells in vivo by FCM analysis. Loss of CDKN2A but not ARF restored the depletion of ETV7 LT-HSCs. Moreover, loss of CDKN2A rescued the defect of repopulation ability in vivo and self-renewal activity in vitro of ETV7 HSPCs. These results indicate that exhaustion of HSC in ETV7 BM occurred through ETV7-induced activation of cell proliferation and the CDKN2A tumor suppressor pathway in mice. Disclosures: No relevant conflicts of interest to declare.

p38α Activates Purine Metabolism to Initiate Hematopoietic Stem Cell Cycling

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 776-776
Author(s):  
Daiki Karigane ◽  
Shinichiro Okamoto ◽  
Toshio Suda ◽  
Keiyo Takubo
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Purine Metabolism ◽  
Stress Conditions ◽  
Wild Type ◽  
Cycle Progression ◽  
Hematopoietic Stem ◽  
Deficient Mice

Abstract Hematopoietic stem cells (HSCs) maintain quiescence by activating specific metabolic pathways, including glycolysis. However, how stress hematopoiesis, including bone marrow transplantation (BMT), induces metabolic changes in HSCs remains unclear. Here, we report a critical role for the p38MAPK family isoform p38α in initiating HSC proliferation during stress hematopoiesis in mouse. First, we identified p38α as the major p38MAPK isozyme highly expressed in HSCs and we also performed conditional knockout of p38α in mice. This mouse showed no overt difference relative to wild type mouse. However, treatment of p38α-deficient mice with 5-FU exhibited defective recovery of hematopoiesis, and the survival rate were lower in p38α-deficient mice than wild-type mice (42.9%, N=7, p38α-deficient mice, vs 100%, wild-type mice, N=6, p=0.03) and loss of p38α in HSCs showed a defective transplantation capacity in primary and secondary transplantation. To gain further insight into p38MAPK function during hematological stress, we evaluated the time course of p38MAPK activation in stressful contexts by intracellular flow cytometry. We found that p38MAPK was immediately phosphorylated in HSCs after hematological stress and returned to normal in a short period, suggesting that p38α functions rapidly after hematological stresses to activate downstream events. To identify events downstream of p38α after hematological stress, we initially evaluated mechanisms such as homing, apoptosis, and ROS generation immediately after BMT. However, defects seen in p38α-deficient HSCs after hematological stress could not be explained by these mechanisms. Therefore we next focused on cell cycle. In CFSE assay, p38α loss resulted in defective recovery from hematological stress and a delay in initiating cycling of HSCs. In addition, p38α-deficient HSCs showed lower BrdU incorporation in vivo (p=0.045) and EdU incorporation in vitro (p=0.003). Transcriptome analysis of transplanted wild-type or p38α-deficient HSCs suggested that p38α-deficient HSCs showed lower enrichment of genes related to HSC-related markers and proliferation. Taken together, loss of p38α resulted in defective HSC cell cycle progression in stressed settings such as transplantation. Given that altered metabolic activities can change cell cycle status, we asked whether p38α regulation of a particular metabolic pathway could initiate HSC cycling under stress conditions. To do so, we collected p38α-deficient or wild-type LSK cells either at steady state or after BMT and extracted metabolites for metabolome analysis using mass spectrometry. Among metabolites surveyed, we focused on changes in glycine and aspartic acid, which are required for purine biosynthesis. Levels of both increased in p38α-deficient as compared with wild-type LSK cells after BMT. Also, mice transplanted with p38α-deficient compared with wild-type LSK cells showed lower levels of allantoin, a product of purine catabolism. These findings suggest that p38α loss suppresses purine metabolism during stress hematopoiesis. Next, we evaluated mRNAs encoding key enzymes functioning in purine metabolism by qPCR. Expression of both inosine-5'-monophosphate dehydrogenase 2 (IMPDH2), and guanosine monophosphate synthetase (GMPS) was significantly decreased in p38α-deficient HSCs relative to wild-type HSCs on day 1 after BMT. To assess how changes in purine metabolism could affect the HSC response to stress, we treated HSCs with cytokines in the presence or absence of mycophenolic acid (MPA), an IMPDH2 inhibitor. MPA treatment significantly suppressed colony formation capacity of HSCs in a dose-dependent manner. Also, EdU incorporation into HSCs was reduced by MPA dose-dependently. Finally, isolated HSCs were cultured with or without MPA for 3 days and then transplanted into recipients along with competitor cells. PB chimerism was dose-dependently decreased in recipients of MPA-treated cells. These findings suggest that purine metabolism directly maintains proliferation capacity of HSCs in stress conditions. In summary, expression of purine-synthesizing enzymes decreased in p38α-deficient HSCs after transplantation, an activity correlated with defective cell cycle progression in vitro and in vivo. Overall, this is the first report of p38α-regulated changes in purine metabolism associated with HSC stress and cell cycle initiation. Disclosures No relevant conflicts of interest to declare.

scholarly journals BRD4 PROTAC degrader ARV-825 inhibits T-cell acute lymphoblastic leukemia by targeting 'Undruggable' Myc-pathway genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shuiyan Wu ◽  
You Jiang ◽  
Yi Hong ◽  
Xinran Chu ◽  
Zimu Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Caspase 3 ◽  
Lymphoblastic Leukemia ◽  
Rna Seq ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Bet Protein

Abstract Background T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease with a high risk of induction failure and poor outcomes, with relapse due to drug resistance. Recent studies show that bromodomains and extra-terminal (BET) protein inhibitors are promising anti-cancer agents. ARV-825, comprising a BET inhibitor conjugated with cereblon ligand, was recently developed to attenuate the growth of multiple tumors in vitro and in vivo. However, the functional and molecular mechanisms of ARV-825 in T-ALL remain unclear. This study aimed to investigate the therapeutic efficacy and potential mechanism of ARV-825 in T-ALL. Methods Expression of the BRD4 were determined in pediatric T-ALL samples and differential gene expression after ARV-825 treatment was explored by RNA-seq and quantitative reverse transcription-polymerase chain reaction. T-ALL cell viability was measured by CCK8 assay after ARV-825 administration. Cell cycle was analyzed by propidium iodide (PI) staining and apoptosis was assessed by Annexin V/PI staining. BRD4, BRD3 and BRD2 proteins were detected by western blot in cells treated with ARV-825. The effect of ARV-825 on T-ALL cells was analyzed in vivo. The functional and molecular pathways involved in ARV-825 treatment of T-ALL were verified by western blot and chromatin immunoprecipitation (ChIP). Results BRD4 expression was higher in pediatric T-ALL samples compared with T-cells from healthy donors. High BRD4 expression indicated a poor outcome. ARV-825 suppressed cell proliferation in vitro by arresting the cell cycle and inducing apoptosis, with elevated poly-ADP ribose polymerase and cleaved caspase 3. BRD4, BRD3, and BRD2 were degraded in line with reduced cereblon expression in T-ALL cells. ARV-825 had a lower IC50 in T-ALL cells compared with JQ1, dBET1 and OTX015. ARV-825 perturbed the H3K27Ac-Myc pathway and reduced c-Myc protein levels in T-ALL cells according to RNA-seq and ChIP. In the T-ALL xenograft model, ARV-825 significantly reduced tumor growth and led to the dysregulation of Ki67 and cleaved caspase 3. Moreover, ARV-825 inhibited cell proliferation by depleting BET and c-Myc proteins in vitro and in vivo. Conclusions BRD4 indicates a poor prognosis in T-ALL. The BRD4 degrader ARV-825 can effectively suppress the proliferation and promote apoptosis of T-ALL cells via BET protein depletion and c-Myc inhibition, thus providing a new strategy for the treatment of T-ALL.

scholarly journals Synthesis and Two-Dimensional 1Η and 13C NMR Investigations of an Inhibitor of Hematopoietic Stem Cell Proliferation Ac–Ser–Asp–Lys–Pro–OH

1992 ◽  
Vol 47 (9) ◽  
pp. 1324-1332 ◽  
Author(s):  
Jens Freund ◽  
Afroditi Kapurniotu ◽  
Tadeusz A. Holak ◽  
Maryse Lenfant ◽  
Wolfgang Voelter
Keyword(s):  
Cell Proliferation ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Solid Phase ◽  
Water Solution ◽  
Random Coil ◽  
Hematopoietic Stem ◽  
Stem Cell Proliferation ◽  
Equilibrium Ratio

The solid phase synthesis of the inhibitor of hematopoietic stem cell proliferation, Ac–Ser–Asp–Lys–Pro–OH, and its derivative Ac–Ala–Asp–Lys–Pro–OH is described. 1H and 13C NMR investigations demonstrate that both peptides show no prefered conformation in water solution. Both peptides exist in a Pro-cis-trans equilibrium ratio of 9 (trans) : 1 (cis). Thymosin β4 is believed to be the precursor molecule of the tetrapeptide Ac–SDKP. The attachement of the random coil tetrapeptide to a rigid helical fragment could facilitate its in vivo enzymatic cleavage.

scholarly journals Tanshinone IIA Inhibits Osteosarcoma Growth through a Src Kinase-Dependent Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chao Hu ◽  
Xiaobin Zhu ◽  
Taogen Zhang ◽  
Zhouming Deng ◽  
Yuanlong Xie ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Src Kinase ◽  
Akt Signaling ◽  
Cellular Level ◽  
Tanshinone Iia

Introduction. Osteosarcoma is a malignant tumor associated with high mortality rates due to the toxic side effects of current therapeutic methods. Tanshinone IIA can inhibit cell proliferation and promote apoptosis in vitro, but the exact mechanism is still unknown. The aims of this study are to explore the antiosteosarcoma effect of tanshinone IIA via Src kinase and demonstrate the mechanism of this effect. Materials and Methods. Osteosarcoma MG-63 and U2-OS cell lines were stable transfections with Src-shRNA. Then, the antiosteosarcoma effect of tanshinone IIA was tested in vitro. The protein expression levels of Src, p-Src, p-ERK1/2, and p-AKt were detected by Western blot and RT-PCR. CCK-8 assay and BrdU immunofluorescence assay were used to detect cell proliferation. Transwell assay, cell scratch assay, and flow cytometry were used to detect cell invasion, migration, and cell cycle. Tumor-bearing nude mice with osteosarcoma were constructed. The effect of tanshinone IIA was detected by tumor HE staining, tumor inhibition rate, incidence of lung metastasis, and X-ray. Results. The oncogene role of Src kinase in osteosarcoma is reflected in promoting cell proliferation, invasion, and migration and in inhibiting apoptosis. However, Src has different effects on cell proliferation, apoptosis, and cell cycle regulation among cell lines. At a cellular level, the antiosteosarcoma effect of tanshinone IIA is mediated by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways. At the animal level, tanshinone IIA played a role in resisting osteosarcoma formation by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways. Conclusion. Tanshinone IIA plays an antiosteosarcoma role in vitro and in vivo and inhibits the progression of osteosarcoma mediated by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways.

scholarly journals Positive feedback between lncRNA FLVCR1-AS1 and KLF10 may inhibit pancreatic cancer progression via the PTEN/AKT pathway

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Jiewei Lin ◽  
Shuyu Zhai ◽  
Siyi Zou ◽  
Zhiwei Xu ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Pancreatic Cancer ◽  
Cell Proliferation ◽  
Cancer Progression ◽  
Positive Feedback ◽  
Molecular Mechanisms ◽  
Tumor Tissues ◽  
And Migration

Abstract Background FLVCR1-AS1 is a key regulator of cancer progression. However, the biological functions and underlying molecular mechanisms of pancreatic cancer (PC) remain unknown. Methods FLVCR1-AS1 expression levels in 77 PC tissues and matched non-tumor tissues were analyzed by qRT-PCR. Moreover, the role of FLVCR1-AS1 in PC cell proliferation, cell cycle, and migration was verified via functional in vitro and in vivo experiments. Further, the potential competitive endogenous RNA (ceRNA) network between FLVCR1-AS1 and KLF10, as well as FLVCR1-AS1 transcription levels, were investigated. Results FLVCR1-AS1 expression was low in both PC tissues and PC cell lines, and FLVCR1-AS1 downregulation was associated with a worse prognosis in patients with PC. Functional experiments demonstrated that FLVCR1-AS1 overexpression significantly suppressed PC cell proliferation, cell cycle, and migration both in vitro and in vivo. Mechanistic investigations revealed that FLVCR1-AS1 acts as a ceRNA to sequester miR-513c-5p or miR-514b-5p from the sponging KLF10 mRNA, thereby relieving their suppressive effects on KLF10 expression. Additionally, FLVCR1-AS1 was shown to be a direct transcriptional target of KLF10. Conclusions Our research suggests that FLVCR1-AS1 plays a tumor-suppressive role in PC by inhibiting proliferation, cell cycle, and migration through a positive feedback loop with KLF10, thereby providing a novel therapeutic strategy for PC treatment.

Effect and mechanism of YB-1 knockdown on glioma cell growth, migration, and apoptosis

2020 ◽  
Vol 52 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Huilin Gong ◽  
Shan Gao ◽  
Chenghuan Yu ◽  
Meihe Li ◽  
Ping Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Growth ◽  
Glioma Cell ◽  
Cell Transformation ◽  
Malignant Cell ◽  
Protein Levels ◽  
Glioma Progression

Abstract Y-box binding protein 1 (YB-1) is manifested as its involvement in cell proliferation and differentiation and malignant cell transformation. Overexpression of YB-1 is associated with glioma progression and patient survival. The aim of this study is to investigate the influence of YB-1 knockdown on glioma cell progression and reveal the mechanisms of YB-1 knockdown on glioma cell growth, migration, and apoptosis. It was found that the knockdown of YB-1 decreased the mRNA and protein levels of YB-1 in U251 glioma cells. The knockdown of YB-1 significantly inhibited cell proliferation, colony formation, and migration in vitro and tumor growth in vivo. Proteome and phosphoproteome data revealed that YB-1 is involved in glioma progression through regulating the expression and phosphorylation of major proteins involved in cell cycle, adhesion, and apoptosis. The main regulated proteins included CCNB1, CCNDBP1, CDK2, CDK3, ADGRG1, CDH-2, MMP14, AIFM1, HO-1, and BAX. Furthermore, it was also found that YB-1 knockdown is associated with the hypo-phosphorylation of ErbB, mTOR, HIF-1, cGMP-PKG, and insulin signaling pathways, and proteoglycans in cancer. Our findings indicated that YB-1 plays a key role in glioma progression in multiple ways, including regulating the expression and phosphorylation of major proteins associated with cell cycle, adhesion, and 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.

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