Colony-forming Capacity Research Articles

A Novel Xeno-Free Method to Isolate Human Endometrial Mesenchymal Stromal Cells (E-MSCs) in Good Manufacturing Practice (GMP) Conditions.

The cyclic regeneration of human endometrium is guaranteed by the proliferative capacity of endometrial mesenchymal stromal cells (E-MSCs). Due to this, the autologous infusion of E-MSCs has been proposed to support endometrial growth in a wide range of gynecological diseases. We aimed to compare two different endometrial sampling methods, surgical curettage and vacuum aspiration biopsy random assay (VABRA), and to validate a novel xeno-free method to culture human E-MSCs. Six E-MSCs cell samples were isolated after mechanical tissue homogenization and cultured using human platelet lysate. E-MSCs were characterized for the colony formation capacity, proliferative potential, and multilineage differentiation. The expression of mesenchymal and stemness markers were tested by FACS analysis and real-time PCR, respectively. Chromosomal alterations were evaluated by karyotype analysis, whereas tumorigenic capacity and invasiveness were tested by soft agar assay. Both endometrial sampling techniques allowed efficient isolation and expansion of E-MSCs using a xeno-free method, preserving their mesenchymal and stemness phenotype, proliferative potential, and limited multi-lineage differentiation ability during the culture. No chromosomal alterations and invasive/tumorigenic capacity were observed. Herein, we report the first evidence of efficient E-MSCs isolation and culture in Good Manufacturing Practice compliance conditions, suggesting VABRA endometrial sampling as alternative to surgical curettage.

Deltex E3 ubiquitin ligase 3 inhibits colorectal cancer cell growth and regulates cell cycle progression via upregulating E2F transcription factor 1

BackgroundThe mortality rate of colorectal cancer (CRC) remains high in developing countries. Interventions that can inhibit the proliferation of tumor cells represent promising strategies in CRC treatment. Deltex E3 ubiquitin ligase 3 (DTX3) plays an essential role in tumor development and may predict the outcome of cancer patients. This study aimed to investigate the regulatory mechanisms of DTX3 in CRC progression.Methods and resultsThe expression of DTX3 was significantly downregulated in CRC tissues relative to normal colorectal tissues. DTX3 overexpression inhibited, while DTX3 knockout promoted the colony-forming capacity and proliferation of CRC cells. E2F transcription factor 1 (E2F1) is a key mediator of cell cycle progression that participates in the progression, metastasis, and chemoresistance of CRC. Further analysis revealed that DTX3 regulated the transcriptional activity of E2F1 in CRC cells. The transcription by E2F1 was significantly reduced with the increase in the cellular level of DTX3, while DTX3 knockout exerted an opposite effect. DTX3 knockout also increased the expression of E2F1 target genes involved in cell cycle progression, CDC2 and Cyclin D3, while PD 0332991, an inhibitor of E2F1 transcription, inhibited the expression of both proteins.ConclusionsIn conclusion, DTX3 regulated CRC cell growth via regulating E2F1 and its downstream genes. These findings support further exploration of DTX3 as a potential therapeutic target for CRC.

A comparative study of pathogen inactivation technologies in human platelet lysate and its optimal efficiency in human placenta-derived stem cells culture

BackgroundPathogen inactivation (PI) is necessary for the pooled components derived from a biological source. Recently, the use of human platelet lysate (hPL) has increased in the cell manufacturing process as a xeno-free substitute for Fetal Bovine Serum (FBS). Therefore, an effective PI process to produce a pathogen-free hPL with the optimal efficiency in the manufacturing of cell therapy products is a vital requirement. Study design and methodsTo evaluate the efficacy of gamma irradiation and riboflavin/ultraviolet light (RB/UV) as PI methods for hPL, the reduction factor (RF) of titer of model viruses and bacteria were examined. Furthermore, the effect of different PI methods on the hPL performance was evaluated by the in vitro expansion of human placenta-derived mesenchymal stem cells (PLMSCs). To compare different study groups, the growth kinetic, immunophenotype, colony formation, and differentiation capacity (osteogenic and adipogenic) of PLMSCs were examined. In addition, the concentration of growth factors was assayed in each study group. ResultsAchievement to the RF more than 5 log10 for all pathogens, showed the effectiveness of two PI methods. In comparison with the other study groups, the dose of 45 kGy gamma irradiation considerably decreased the growth factor level of the hPL. It also showed a significant adverse effect on PLMSCs growth kinetics. The dose of 30 KGy gamma irradiation and RB/UV demonstrated a favorable effect on different assays of the in vitro expanded PLMSCs. ConclusionThe 30 KGy gamma irradiation and RB/UV were effective in the RF of the viral and bacterial models of the contaminated hPL. The efficacy of these PI-hPLs for PLMSCs expansion was preserved. To increase the safety of cell therapy products, PI methods should be considered for the hPL preparations.

Human embryonic mesenchymal lung-conditioned medium promotes differentiation to myofibroblast and loss of stemness phenotype in lung adenocarcinoma cell lines

BackgroundWhen genes responsible for normal embryonic development are abnormally expressed in adults, it can lead to tumor development. This can suggest that the same mechanism that controls embryonic differentiation can also control tumor differentiation. We hypothesize that the malignant phenotype of lung cancer cells could acquire benign characteristics when in contact with an embryonic lung microenvironment. We cultured two lung cancer cell lines in embryonic lung mesenchyme-conditioned medium and evaluated morphological, functional and molecular changes.MethodsThe human embryonic mesenchymal lung-conditioned medium (hEML-CM) was obtained by culturing lung cells from embryos in the pseudoglandular stage of development. The NSCLC cell lines A549 and H1299 we cultured in the hEML-CM and in a tumor-conditioned medium. Morphological changes were analyzed with optical and transmission electron microscopy. To evaluate the functional effect of conditioned medium in tumor cells, we analyzed cell proliferation, migration, colony formation capacity in 2D and 3D and in vivo tumor growth capacity. The expression of the pluripotency genes OSKM, the adenocarcinoma marker NKX2-1, the lung surfactant proteins SFTP, the myofibroblast marker MYH and DNMT3A/3B was analyzed with qRT-PCR and the presence of the myofibroblast markers vimentin and α-SMA with immunofluorescence. Transcriptomic analysis was performed using Affymetrix arrays.ResultsThe A549 and H1299 cells cultured in hEML-CM lost their epithelial morphology, acquired mesodermal characteristics, and decreased proliferation, migration, and colony formation capacity in 2D and 3D, as well as reduced its capacity to growth in vivo. The expression of OSKM, NKX2-1 and SFTP decreased, while that of DNMT3A/3B, vimentin, α-SMA and MYH increased. Distant matrix analysis based on transcriptomic profile showed that conditioned cells were closer to myoblast and human lung fibroblast than to normal epithelial immortalized lung cells. A total of 1631 for A549 and 866 for H1299 differentially expressed genes between control and conditioned cells were identified.ConclusionsTo the best of our knowledge, this is the first study to report that stimuli from the embryonic lung can modulate the malignant phenotype of lung cancer cells, control their growth capacity and activate their differentiation into myofibroblasts. These findings could lead to new strategies for lung cancer management.

Novel piperazine-substituted silicon phthalocyanines exert anti-cancer effects against breast cancer cells

BackgroundPhotodynamic therapy (PDT) is one of the effective methods that can be used in cancer treatment. In this study, we aimed to investigate the PDT-mediated anti-cancer effects of newly synthesized piperazine-substituted silicon phthalocyanine molecules on breast cancer cells. MethodsThe compounds were analyzed by different spectroscopic techniques (FT-IR, UV–vis, 1H NMR, 13C NMR, MS) and the absorbance characteristics were determined. The cytotoxic effects of silicon phthalocyanines on MDA-MB-231 breast cancer cells and non-tumorigenic MCF-10A cells were evaluated using MTT assay. Detection of apoptotic populations was performed by Annexin V/7AAD assay. H2DCFDA dye was used to analyze intracellular reactive oxygen species. The clonogenic activity and cellular motility were analyzed by colony formation assay and in vitro scratch assay, respectively. Caspase-3, PARP1, and cleaved-PARP1 protein levels were analyzed by western blot studies. ResultsPiperazine-substituted silicon phthalocyanines caused high levels of cytotoxic effects and apoptotic cell population in MDA-MB-231 cells, while low levels of cytotoxic effects were observed in MCF-10A cells. Following PDT, intense ROS formation was detected in MDA-MB-231 cells. Colony-forming capacity and cellular motility of MDA-MB-231 cells were highly restricted following PDT, whereas these effects were observed at lower levels in MCF-10A cells. Silicon phthalocyanines caused different effects on cleaved-PARP1 expressions of MDA-MB-231 and MCF-10A cells. ConclusionThese results suggest that piperazine-substituted silicon phthalocyanines can exert selective anti-cancer effects on breast cancer cells and activate cellular death through different molecular pathways. Hence, we believe that they may be used as effective photosensitizer agents in the future.

EN1 Regulates Cell Growth and Proliferation in Human Glioma Cells via Hedgehog Signaling.

Glioblastoma is an aggressive cancer of the nervous system that accounts for the majority of brain cancer-related deaths. Through cross-species transcriptome studies, we found that Engrailed 1 (EN1) is highly expressed in serum-free cultured glioma cells as well as glioma tissues, and increased expression level predicts a worse prognosis. EN1 controls glioma cell proliferation, colony formation, migration, and tumorigenic capacity in vivo. It also influences sensitivity of glioma cells to γ-ray irradiation by regulating intracellular ROS levels. Mechanistically, EN1 influences Hedgehog signaling by regulating the level of Gli1 as well as primary cilia length and the primary cilia transport-related protein TULP3. In conclusion, we demonstrate that EN1 acts as an oncogenic regulator that contributes to glioblastoma pathogenesis and could serve as a diagnostic/prognostic marker and therapeutic target for glioblastoma.

Transcriptional activation of Proteasome 26S non-ATPase subunit 7 by forkhead box P3 participates in gastric cancer cell proliferation and apoptosis

ABSTRACT Proteasome 26S non-ATPase subunit 7 (PSMD7) and forkhead box P3 (FOXP3) have been found to be both upregulated in gastric cancer tissues. FOXP3 was also predicted to have binding sites on PSMD7 promoter. Thus, this study investigated the relationship between PSMD7 and FOXP3 and their roles in gastric cancer. Bioinformatic databases predicted PSMD7 expression in non-cancerous gastric tissue and gastric cancer tissue, as well as the correlation between PSMD7 and the overall/disease free survival. PSMD7 expression in non-cancerous gastric tissue or cells and gastric cancer tissue or cells was detected by qPCR and Western blot. After PSMD7 downregulation by siRNA interference, cell viability, colony-forming capacity and cell apoptosis were analyzed with cell counting kit-8 assay, colony formation assay and terminal deoxynucleotidyl transferasemediated dUTP nick end-labeling. Proliferation and apoptosis markers were assayed by qPCR and Western blot. Dual-luciferase reporter and chromatin immunoprecipitation assays were performed to look at the binding relationship between FOXP3 and PSMD7 promoter. Cell proliferation and apoptosis were examined again after co-transfection of PSMD7 siRNA plasmid and FOXP3 overexpression plasmid. PSMD7 expression was much higher in gastric cancer tissue and cell lines. Interference with PSMD7 decreased gastric cancer cell viability, inhibited their proliferation and colony formation and promoted cell apoptosis. FOXP3 was found to bind to PSMD7 promoter and activate PSMD7 expression. Overexpression of FOXP3 could rescue the effects of PSMD7 knockdown on gastric cancer cells. PSMD7 is involved in the proliferation and apoptosis of gastric cancer cells and can be transcriptionally regulated by FOXP3.

The fate of human SUSD2+ endometrial mesenchymal stem cells during decidualization

Regeneration of the endometrial stromal compartment in premenopausal women is likely maintained by the perivascular endometrial mesenchymal stem/stromal cells (eMSC) expressing sushi domain containing 2 (SUSD2). The fate of SUSD2+ eMSC during pregnancy and their role in decidualization is not fully known. The aim of our study was to determine the effect of progesterone on the stemness of the SUSD2+ eMSC isolated from non-pregnant uterine samples. Secondary objectives were to characterize the functional capacity including differentiation and clonogenicity assays of SUSD2+ eMSC isolated from decidua at full term and compare it to the capacity of those isolated from non-pregnant uterine samples. Progesterone treatment induced changes in the decidual gene expression profile in non-pregnant SUSD2+ eMSC. Data analysis of a publicly available single cell RNA-seq data set revealed differential expression of several mesenchymal and epithelial signature genes between the SUSD2+ eMSC and the decidual stromal cells, suggesting mesenchymal-to-epithelial transition occurs during decidualization. Histological analysis revealed a significantly lower abundance of SUSD2+ eMSC in 1st trimester and full term samples compared to non-pregnant samples, p = 0.0296 and 0.005, respectively. The differentiation and the colony forming capacity did not differ significantly between the cells isolated from non-pregnant and pregnant uterine samples. Our results suggest that SUSD2+ eMSC undergo decidualization in vitro, while maintaining MSC plasma membrane phenotype. Human eMSC seem to play an important role in the course of endometrial decidualization and embryo implantation. Pregnancy reduced the abundance of SUSD2+ eMSC, however eMSC function remains intact.

Transcription factor c-Myb: novel prognostic factor in osteosarcoma

The transcription factor c-Myb is an oncoprotein promoting cell proliferation and survival when aberrantly activated/expressed, thus contributing to malignant transformation. Overexpression of c-Myb has been found in leukemias, breast, colon and adenoid cystic carcinoma. Recent studies revealed its expression also in osteosarcoma cell lines and suggested its functional importance during bone development. However, the relevance of c-Myb in control of osteosarcoma progression remains unknown. A retrospective clinical study was carried out to assess a relationship between c-Myb expression in archival osteosarcoma tissues and prognosis in a cohort of high-grade osteosarcoma patients. In addition, MYB was depleted in metastatic osteosarcoma cell lines SAOS-2 LM5 and 143B and their growth, chemosensitivity, migration and metastatic activity were determined. Immunohistochemical analysis revealed that high c-Myb expression was significantly associated with poor overall survival in the cohort and metastatic progression in young patients. Increased level of c-Myb was detected in metastatic osteosarcoma cell lines and its depletion suppressed their growth, colony-forming capacity, migration and chemoresistance in vitro in a cell line-dependent manner. MYB knock-out resulted in reduced metastatic activity of both SAOS-2 LM5 and 143B cell lines in immunodeficient mice. Transcriptomic analysis revealed the c-Myb-driven functional programs enriched for genes involved in the regulation of cell growth, stress response, cell adhesion and cell differentiation/morphogenesis. Wnt signaling pathway was identified as c-Myb target in osteosarcoma cells. Taken together, we identified c-Myb as a negative prognostic factor in osteosarcoma and showed its involvement in the regulation of osteosarcoma cell growth, chemosensitivity, migration and metastatic activity.

Mucin 1 downregulation decreases the anti-tumor effects of melanoma vaccine.

Immunotherapy-based approaches are important breakthroughs with potential treatment benefits for melanoma patients. Mucin 1 (MUC1) is significantly upregulated in melanoma relative to normal cells. It has been reported that MUC1 influences cancer cell proliferation, apoptosis, invasion, and metastasis.The study aimed to explore the effect of MUC1 knockdown on the biological characteristics of the melanoma cell line B16F10 and evaluate whether MUC1 is an effective candidate target antigen for melanoma vaccine development. First, lentiviral vector-mediated short hairpin RNA (shRNA) was used to knockdown MUC1 in B16F10 cells (shMUC1-B16F10 cells). Next, we examined epithelial-mesenchymal transition (EMT), migration, proliferative capacity, clone formation, and distribution of cell cycle in shMUC1-B16F10 cells. Finally, the vaccine was prepared by repeated freeze-thawing of the shMUC1-B16F10 cells and used to subcutaneously immunize C57BL/6 mice, which were then challenged using B16F10 cells 10 days after the final vaccination. It was revealed that shMUC1 suppressed B16F10 proliferative and colony formation capacity, induced the arrest of cell cycle in the G0/G1 phase, and adjusted the expression of EMT-associated factors. MUC1 downregulation markedly suppressed the effect of B16F10 vaccine against melanoma in a mouse model. As compared with B16F10-vaccinated mice, B16F10-vaccinated mice in which MUC1 was silenced had reduced natural killer (NK) cytotoxicity, lower production of interferon-γ (IFN-γ), anti-MUC1 antibodies, perforin, granzyme B, and elevated tumor growth factor-β (TGF-β) level. MUC1 has strong melanoma vaccine immunogenicity, and induces the host's anti-tumor reaction. MUC1 knockdown inhibits the immune activity of B16F10 cell vaccine and anti-melanoma effect, suggesting the MUC1 is an important candidate target antigen of the melanoma vaccine.

Comparison of senescence phenotype of short- and long- term cultured rat mesenchymal stem cells in vitro.

Mesenchymal stem cells present clinical potential to recover and regenerate injured tissues in diverse pathologies. The in vitro expansion and characterization of these cells contribute to elucidation of the mechanisms of senescence and strategies involving cell therapies. This study aimed to compare specific characteristics between initial and advanced passages of mesenchymal stem cells derived from adipose tissue and bone marrow. Both cell types were characterized according to immunophenotype, osteogenic differentiation, genomic instability, migration assay, doubling population time and colony forming ability. Our results demonstrated that both cell types were able to maintain an immunophenotypic profile typical of mesenchymal stem cells during increasing passages. Adipose stem cells at initial passage presented greater migration capacity compared to advanced passage cells, and advanced passage cells proliferated faster than initial passage cells. Bone marrow stem cells at early passages presented higher osteogenic potential than advanced. At advanced passages they presented higher colony forming capacity and genetic damage than those at initial passage. These results suggest that mesenchymal stem cells maintained in culture presented characteristics of senescence that should be monitored prior the use in regenerative medicine and cells derived from bone marrow at initial passage have better potential for therapeutic use in bone tissue engineering.

The Chemosensitizing Effect of Portulaca oleracea Methanol Extract on Human Colorectal and Lung Cancer Cells Against Irinotecan

Cancer is a major health problem and it has been causing great damage in recent years worldwide. Serious side effects of chemotherapeutics used in cancer treatment make natural products valuable. Combined use of chemotherapy drugs and herbal products is an important approach in reducing side effects and revealing a more effective treatment. In this study, the effects of methanolic extract from Portulaca oleracea (POM) alone and in combination with Irinotecan were investigated against human colorectal carcinoma cell line HCT-116 and human lung adenocarcinoma cell line A549. The antiproliferative/anti-colony formation effects were determined using WST-1 assay and clonogenic assay. Cell death detection Elisa assay was employed to exhibite the triggered apoptosis, and quantitative real time polimerase chain reaction (qRT-PCR) was performed to evaluate the mRNA expression of mTOR, Akt and PTEN genes, which are significant modulators of apoptotic and survival pathways. It was determined that 72 h treatment with increasing concentrations of POM (0-1000 mg mL-1) decreased the viability of HCT116 and A549 cells in a dose-dependent manner. Also, POM and Irinotecan exhibited synergistic effects in both cell lines. The combination of POM and Irinotecan suppressed the colony forming capacity of HCT116 and A549 cells by 84% and 79%, respectively. POM also altered mTOR, Akt and PTEN gene expressions in HCT-116 and A549 carcinoma cells, both alone and in combination with Irinotecan. This study shows that the phytotherapeutic effect of P. oleracea needs to be studied more intensively.

Tomentosin shows anticancer effect on U87 human glioblastoma multiforme cells

Glioblastoma multiforme (GBM) is one of the most common brain tumors. Chemotherapy, radiotherapy and surgical resection are methods used in GBM treatment, however, the investigation of possible anticancer effects of low-toxicity natural products on various cancer cells, including GBM, leads to promising results. In this study, it was aimed to investigate anticancer effect of tomentosin, which is a sesquiterpene lactone, on U87 human GBM cells. The cytotoxic effect of tomentosin was evaluated by XTT assay. The concentration of tomentosin that inhibits 50% cell viability (IC50) was determined by the results from XTT, and, in further analyzes cells were treated with tomentosin at IC50 concentration. Then, total RNA isolation and cDNA synthesis were performed in control and dose groups, and, the possible anticancer effect of tomentosin was determined by evaluating the expression levels of important genes associated with apoptosis and metastasis by qPCR analysis. In addition, the effect of tomentosin on the colony forming capacity of GBM cells was evaluated by colony formation assay. According to our results, IC50 dose of tomentosin was found to be 28.8 µM in U87 cells for 48 hours. When compared to the control group, tomentosin increased expression of BAX, CASP3, CASP8, CASP9, CYCS, FADD, TNF, TNFR1, TNFR2 and TIMP2 genes. And, tomantosin significantly decreased colony forming capacity of U87 cells. In conclusion, it is thought that tomentosin exerts its anticancer effect by changing the expression levels of genes associated with apoptosis and metastasis in U87 GBM cells.

The effects of Acyclovir administration to NCI-H1975 non-small cell lung cancer cells

The biochemical mechanisms by which the antiviral drug Acyclovir (ACV) may induce anticancer effects even without detecting human herpesviruses (HHVs) are still poorly understood. Herein, we investigated for the first time how NCI-H1975 non-small cell lung cancer cells responded in vitro to ACV administration by exploring mitochondrial damage and apoptosis induction. We confirmed ACV ability to cause the inhibition of cancer cell growth even without detecting intracellular HHVs; the drug also significantly inhibited the colony formation capacity of NCI-H1975 cells. Cell cycle analysis revealed an increase of the sub-G1 hypodiploid peak after ACV treatment; the activation of caspase-3 and the presence of DNA laddering sustained the capacity of the drug to induce apoptotic cell death. Regarding mitochondrial toxicity, a reduction of mitochondrial membrane potential, altered mitochondrial size and shape, and mtDNA damage were found after ACV administration. Furthermore, an increment of intracellular reactive oxygen species levels as well as the upregulation of NudT3 involved in DNA repair mechanisms were observed. Altogether, these findings suggest that mitochondria may be possible initial targets and/or sites of ACV cytotoxicity within cancer cells in the absence of intracellular HHVs.

Gab2 deficiency prevents Flt3-ITD driven acute myeloid leukemia in vivo

Internal tandem duplications (ITD) of the FMS-like tyrosine kinase 3 (FLT3) predict poor prognosis in acute myeloid leukemia (AML) and often co-exist with inactivating DNMT3A mutations. In vitro studies implicated Grb2-associated binder 2 (GAB2) as FLT3-ITD effector. Utilizing a Flt3-ITD knock-in, Dnmt3a haploinsufficient mouse model, we demonstrate that Gab2 is essential for the development of Flt3-ITD driven AML in vivo, as Gab2 deficient mice displayed prolonged survival, presented with attenuated liver and spleen pathology and reduced blast counts. Furthermore, leukemic bone marrow from Gab2 deficient mice exhibited reduced colony-forming unit capacity and increased FLT3 inhibitor sensitivity. Using transcriptomics, we identify the genes encoding for Axl and the Ret co-receptor Gfra2 as targets of the Flt3-ITD/Gab2/Stat5 axis. We propose a pathomechanism in which Gab2 increases signaling of these receptors by inducing their expression and by serving as downstream effector. Thereby, Gab2 promotes AML aggressiveness and drug resistance as it incorporates these receptor tyrosine kinases into the Flt3-ITD signaling network. Consequently, our data identify GAB2 as a promising biomarker and therapeutic target in human AML.

Circ_0000620 acts as an oncogenic factor in gastric cancer through regulating MMP2 expression via sponging miR-671-5p

BackgroundGastric cancer (GC) is one of the most common cancers in the digestive system. Circular RNAs (circRNAs) have been found to function as important regulators in the pathogenesis of GC. This study focused on the biological role and molecular mechanism of circ_0000620 in GC progression.MethodsThe expression levels of circ_0000620, microRNA-671-5p (miR-671-5p) and Matrix MetalloProteinase 2 (MMP2) were measured by quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) assay or western blot. The stability of circ_0000620 was confirmed by Ribonuclease R (RNase R) assay. The protein levels were determined by western blot assay. Cell viability, colony formation, cell migratory ability, cell invasive ability and tube formation capacity were respectively examined by CCK-8 assay, colony formation assay, wound healing assay, transwell invasion assay and tube formation assay. The interaction between miR-671-5p and circ_0000620 or MMP2 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay. The role of circ_0000620 in GC undefined was explored by xenograft tumor assay.ResultsCirc_0000620 was conspicuously upregulated in GC tissues and cells. Circ_0000620 knockdown reduced cell viability, colony formation, migration, invasion and tube formation capacity of GC cells in vitro. Furthermore, MMP2 was upregulated in GC and MMP2 overexpression reversed the anti-tumor response of circ_0000620 knockdown in GC progression. Moreover, circ_0000620 directly interacted with miR-671-5p and circ_0000620 downregulation regulated malignant behaviors of GC cells by upregulating miR-671-5p. In addition, silencing of circ_0000620 inhibited tumor growth in vivo.ConclusionsCirc_0000620 knockdown inhibited the malignant development of GC partly through modulating the miR-671-5p/MMP2 axis.

HnRNPA1/UP1 Unfolds KRAS G-Quadruplexes and Feeds a Regulatory Axis Controlling Gene Expression.

Recent studies have proven that the genetic landscape of pancreatic cancer is dominated by the KRAS oncogene. Its transcription is controlled by a G-rich motif (called 32R) located immediately upstream of the TSS. 32R may fold into a G-quadruplex (G4) in equilibrium between two G4 conformers: G9T (TM = 61.2 °C) and G25T (TM = 54.7 °C). We found that both G4s bind to hnRNPA1 and its proteolytic fragment UP1, promoting several contacts with the RRM protein domains. 1D NMR analysis of DNA imino protons shows that, upon binding to UP1, G25T is readily unfolded at both 5′ and 3′ tetrads, while G9T is only partially unfolded. The impact of hnRNPA1 on KRAS expression was determined by comparing Panc-1 cells with two Panc-1 knockout cell lines in which hnRNPA1 was deleted by the CRISPR/Cas9 technology. The results showed that the expression of KRAS is inhibited in the knockout cell lines, indicating that hnRNPA1 is essential for the transcription of KRAS. In addition, the knockout cell lines, compared to normal Panc-1 cells, show a dramatic decrease in cell growth and capacity of colony formation. Pull-down and Western blot experiments indicate that conformer G25T is a better platform than conformer G9T for the assembly of the transcription preinitiation complex with PARP1, Ku70, MAZ, and hnRNPA1. Together, our data prove that hnRNPA1, being a key transcription factor for the activation of KRAS, can be a new therapeutic target for the rational design of anticancer strategies.

Elp1 facilitates RAD51-mediated homologous recombination repair via translational regulation

BackgroundRAD51-dependent homologous recombination (HR) is one of the most important pathways for repairing DNA double-strand breaks (DSBs), and its regulation is crucial to maintain genome integrity. Elp1 gene encodes IKAP/ELP1, a core subunit of the Elongator complex, which has been implicated in translational regulation. However, how ELP1 contributes to genome maintenance is unclear.MethodsTo investigate the function of Elp1, Elp1-deficient mouse embryonic fibroblasts (MEFs) were generated. Metaphase chromosome spreading, immunofluorescence, and comet assays were used to access chromosome abnormalities and DSB formation. Functional roles of Elp1 in MEFs were evaluated by cell viability, colony forming capacity, and apoptosis assays. HR-dependent DNA repair was assessed by reporter assay, immunofluorescence, and western blot. Polysome profiling was used to evaluate translational efficiency. Differentially expressed proteins and signaling pathways were identified using a label-free liquid chromatography–tandem mass spectrometry (LC–MS/MS) proteomics approach.ResultsHere, we report that Elp1 depletion enhanced genomic instability, manifested as chromosome breakage and genotoxic stress-induced genomic DNA fragmentation upon ionizing radiation (IR) exposure. Elp1-deficient cells were hypersensitive to DNA damage and exhibited impaired cell proliferation and defective HR repair. Moreover, Elp1 depletion reduced the formation of IR-induced RAD51 foci and decreased RAD51 protein levels. Polysome profiling analysis revealed that ELP1 regulated RAD51 expression by promoting its translation in response to DNA damage. Notably, the requirement for ELP1 in DSB repair could be partially rescued in Elp1-deficient cells by reintroducing RAD51, suggesting that Elp1-mediated HR-directed repair of DSBs is RAD51-dependent. Finally, using proteome analyses, we identified several proteins involved in cancer pathways and DNA damage responses as being differentially expressed upon Elp1 depletion.ConclusionsOur study uncovered a molecular mechanism underlying Elp1-mediated regulation of HR activity and provides a novel link between translational regulation and genome stability.

Anticancer Impact of Nitric Oxide (NO) and NO Combination with SMYD-3 Inhibitor on Breast Carcinomas.

Despite enormous advances in the detection and treatment of breast cancer, it still remains the leading cancer diagnosis and has the second highest mortality rate. Thus, breast cancer research is a high priority for academics and clinicians alike. Based on previous research indicating the potential of nitric oxide (NO) and SMYD-3 inhibition, this work sought to expand upon these concepts and combine the two approaches. Both NO (from S-Nitrosoglutathione (GSNO)), termed Group 1, and a combination therapeutic, inhibitor-4 (SMYD-3 inhibitor) plus NO (from GSNO), termed Group 2, were evaluated for their efficacy on breast carcinoma cell lines MCF7 and MDA-MB-231, and the normal MCF10A breast cell line, using cellular viability, colony formation capacity, cytotoxicity, and cellular apoptosis analysis. These results indicated that, in Group 1, breast carcinoma lines MCF7 and MDA-MB-231, cells experienced a moderate reduction in cellular viability (~20–25%), a large reduction in colony formation capacity (~80–90%), a moderate increase in the relative number of dead cells, and a moderate increase in cellular apoptosis. Group 2 was significantly more impactful, with a ~50% knockdown in cellular viability, a 100% reduction in colony formation capacity, a large increase in the relative number of dead cells, and a large increase in cellular apoptosis. Additionally, Group 2 induced a very small impact on the normal MCF10A cell line. Cumulatively, this work revealed the exciting impact of this combination therapeutic, indicating its potential for clinical application and further research.

The IL-3, IL-5, and GM-CSF common receptor beta chain mediates oncogenic activity of FLT3-ITD-positive AML

FLT3-ITD is the most predominant mutation in AML being expressed in about one-third of AML patients and is associated with a poor prognosis. Efforts to better understand FLT3-ITD downstream signaling to possibly improve therapy response are needed. We have previously described FLT3-ITD-dependent phosphorylation of CSF2RB, the common receptor beta chain of IL-3, IL-5, and GM-CSF, and therefore examined its significance for FLT3-ITD-dependent oncogenic signaling and transformation. We discovered that FLT3-ITD directly binds to CSF2RB in AML cell lines and blasts isolated from AML patients. A knockdown of CSF2RB in FLT3-ITD positive AML cell lines as well as in a xenograft model decreased STAT5 phosphorylation, attenuated cell proliferation, and sensitized to FLT3 inhibition. Bone marrow from CSF2RB-deficient mice transfected with FLT3-ITD displayed decreased colony formation capacity and delayed disease onset together with increased survival upon transplantation into lethally irradiated mice. FLT3-ITD-dependent CSF2RB phosphorylation required phosphorylation of the FLT3 juxtamembrane domain at tyrosines 589 or 591, whereas the ITD insertion site and sequence were of no relevance. Our results demonstrate that CSF2RB participates in FLT3-ITD-dependent oncogenic signaling and transformation in vitro and in vivo. Thus, CSF2RB constitutes a rational treatment target in FLT3-ITD-positive AML.