Increment of nonreceptor tyrosine kinase Arg RNA as evaluated by semiquantitative RT-PCR in granulocyte and macrophage-like differentiation of HL-60 cells

Targeting tumor vascularization: promising strategies for vascular normalization

Tumor recurrence after the clinical cure of tumor often results from the presence of an abnormal microenvironment, including an aberrant vasculature. The tumor microenvironment is rich in pro-angiogenic factors but lacks pro-maturation factors. Pro-angiogenic conditions in the tumor microenvironment, such as hypoxia, are double-edged swords, promoting both the repair of normal tissues and the development of an abnormal blood vessel network. The coexistence of perfusion and hypoxic zones and uneven blood vessel distribution in tumor tissues profoundly influence tumor deterioration, recurrence, and metastasis. Traditional anti-angiogenic therapies have shown limited efficacy, and promote drug resistance, and even metastasis. In contrast, vascular normalization therapy induces a more physiological-like state, leading to better outcomes and fewer side effects. Vascular normalization entails modifying the tumor vascular system to improve tumor oxygenation and substance transport, thereby contributing to improving the efficacy of radiotherapy, chemotherapy, and immunotherapy. This review mainly focuses on the process of tumor vascularization; potential therapeutic targets, including cells, metabolism, signaling pathways, and angiogenesis-related genes; and possible strategies to normalize blood vessels through regulating tumor vessel generation, the development of tumor vessels, and blood vessel fusion and pruning.

Targeting ABL1 or ARG Tyrosine Kinases to Restrict HIV-1 Infection in Primary CD4+ T-Cells or in Humanized NSG Mice

BACKGROUND

Previous studies support dasatinib as a potent inhibitor of HIV-1 replication. However, a functional distinction between 2 kinase targets of the drug, ABL1 and ARG, has not been assessed.

SETTING

We used primary CD4 T-cells, CD8-depleted peripheral blood mononuclear cells (PBMCs) from a treatment naïve HIV-1 patient, and a humanized mouse model of HIV-1 infection. We assessed the roles of ABL1 and ARG during HIV-1 infection and use of dasatinib as a potential antiviral against HIV-1 in humanized mice.

METHODS

Primary CD4 T-cells were administered siRNA targeting ABL1 or ARG, then infected with HIV-1 containing luciferase reporter viruses. Quantitative polymerase chain reaction of viral integration of 4 HIV-1 strains was also assessed. CD8-depleted PBMCs were treated for 3 weeks with dasatinib. NSG mice were engrafted with CD34 pluripotent stem cells from human fetal cord blood, and infected with Ba-L virus after 19 weeks. Mice were treated daily with dasatinib starting 5 weeks after infection.

RESULTS

siRNA knockdown of ABL1 or ARG had no effect on viral reverse transcripts, but increased 2-LTR circles 2- to 4-fold and reduced viral integration 2- to 12-fold. siRNA knockdown of ARG increased SAMHD1 activation, whereas knockdown of either kinase reduced RNA polymerase II activation. Treating CD8-depleted PBMCs from a treatment-naïve patient with 50 nM of dasatinib for 3 weeks reduced p24 levels by 99.8%. Ba-L (R5)-infected mice injected daily with dasatinib showed a 95.1% reduction in plasma viral load after 2 weeks of treatment.

CONCLUSIONS

We demonstrate a novel nuclear role for ABL1 and ARG in ex vivo infection experiments, and proof-of-principle use of dasatinib in a humanized mouse model of HIV-1 infection.

Macrophage Polarization in the Development and Progression of Ovarian Cancers: An Overview

Ovarian cancer is the most lethal gynecological malignancy worldwide. Most patients are diagnosed at late stages because of atypical symptoms and the lack of effective early diagnostic measures. The mechanisms underlying the oncogenesis and development of ovarian cancer are not clear. Macrophages, immune cells derived from the innate immune system, have two states of polarization (M1 and M2) that develop in response to different stimuli. The polarization and differentiation of macrophages into the cancer-inhibiting M1 and cancer-promoting M2 types represent the two states of macrophages in the tumor microenvironment. The interaction of polarized macrophages with cancer cells plays a crucial role in a variety of cancers. However, the effects of macrophage M1/M2 polarization on ovarian cancer have not yet been systematically and fully discussed. In this review, we discuss not only the occurrence, development and influences of macrophage polarization but also the association between macrophage polarization and ovarian cancer. The polarization of macrophages into the M1 and M2 phenotypes plays a pivotal role in ovarian cancer initiation, progression, and metastasis, and provides targets for macrophage-centered treatment in the cancer microenvironment for ovarian cancer therapy. We also addressed the regulation of macrophage polarization in ovarian cancer via noncoding RNAs, exosomes, and epigenetics.

Diverse macrophages polarization in tumor microenvironment

Macrophages are traditional innate immune cells that play critical roles in the clearance of pathogens and the maintenance of tissue homeostasis. Accumulating evidence proves that macrophages affect cancer initiation and malignancy. Macrophages can be categorized into two extreme subsets, classically activated (M1) and alternatively activated (M2) macrophages based on their distinct functional abilities in response to microenvironmental stimuli. In a tumor microenvironment, tumor associated macrophages (TAMs) are considered to be of the polarized M2 phenotype that enhances tumor progression and represent a poor prognosis. Furthermore, TAMs enhance tumor angiogenesis, growth, metastasis, and immunosuppression by secreting a series of cytokines, chemokines, and proteases. The regulation of macrophage polarization is considered to be a potential future therapy for cancer management.

One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness.

Primary cell cultures from human renal cortex and renal-cell carcinoma evidence a differential expression of two spliced isoforms of Annexin A3

Primary cell cultures from renal cell carcinoma (RCC) and normal renal cortex tissue of 60 patients have been established, with high efficiency (more than 70%) and reproducibility, and extensively characterized. These cultures composed of more than 90% of normal or tumor tubular cells have been instrumental for molecular characterization of Annexin A3 (AnxA3), never extensively studied before in RCC cells although AnxA3 has a prognostic relevance in some cancer and it has been suggested to be involved in the hypoxia-inducible factor-1 pathway. Western blot analysis of 20 matched cortex/RCC culture lysates showed two AnxA3 protein bands of 36 and 33 kDa, and two-dimensional Western blot evidenced several specific protein spots. In RCC cultures the 36-kDa isoform was significantly down-regulated and the 33-kDa isoform up-regulated. Furthermore, the inversion of the quantitative expression pattern of two AnxA3 isoforms in tumor cultures correlate with hypoxia-inducible factor-1alpha expression. The total AnxA3 protein is down-regulated in RCC cultures as confirmed also in tissues by tissue microarray. Two AnxA3 transcripts that differ for alternative splicing of exon III have been also detected. Real-time PCR quantification in 19 matched cortex/RCC cultures confirms the down-regulation of longer isoform in RCC cells. The characteristic expression pattern of AnxA3 in normal and tumor renal cells, documented in our primary cultures, may open new insight in RCC management.

Eight full-length abelson related gene (Arg) isoforms are constitutively expressed in caki-1 cell line and cell distribution of two isoforms has been analyzed after transfection

The human Arg (Abl2) nonreceptor tyrosine kinase has a role in cytoskeletal rearrangements by its C-terminal F-actin- and microtubule-binding sequences. We have previously identified Arg transcripts with different 5'- and 3'-ends, named respectively long and short 1A and 1B (1AL, 1AS, 1BL, 1BS) and long and short C-termini (CTL and CTS), that have different expression patterns in various cell types. The combination of the different ends permits to predict eight putative full-length Arg transcripts and corresponding proteins. By Reverse Transcription-Long PCR we show here that all eight full-length transcripts are endogenously expressed in Caki-1 cells and the two bands, approximately 10 kDa different, shown by 1-D Western blots of Hek293T and Caki-1 lysates correspond to the full-length Arg protein isoforms with different C-termini. 2-D Western blot analysis evidenced different high molecular weight and slight acidic specific spots in Hek293T and Caki-1 lysates. The cellular localization of two Arg isoforms (1BLCTL and 1BLCTS) transfected in Caki-1 and Hek293T cells was cytoplasmic, and some differences in cytoskeleton interactions have been evidenced. Moreover, in Hek293T cells only the transfected 1BLCTS isoform gives rise to a large intracytoplasmic cylindrical structure containing phalloidin-positive amorphous actin aggregates. The presence of eight full-length Arg isoforms with different cellular expression may imply a diverse functional role in normal and neoplastic cells.

Distinct nuclear arrangement of active and inactive c-myc genes in control and differentiated colon carcinoma cells

Using sequential RNA-DNA fluorescence in situ hybridization, the nuclear arrangement of both the active and inactive c-myc gene as well as its transcription was investigated in colon cancer HT-29 cells induced to differentiate into enterocytes. Cytogenetic studies revealed the presence of two chromosomes 8 in HT-29 cells, of which the one containing c-myc gene amplicons was substantially larger and easily distinguished from the normal chromosome. This observation enabled detection of both activity and nuclear localization of c-myc genes in single cells and in individual chromosome territories. Similar transcriptional activity of the c-myc gene was observed in both the normal and derivative chromosome 8 territories showing no influence of the amplification on the c-myc gene expression. Our experiments demonstrate strikingly specific nuclear and territorial arrangements of active genes as compared with inactive ones: on the periphery of their territories facing to the very central region of the cell nucleus. Nuclear arrangement of c-myc genes and transcripts was conserved during cell differentiation and, therefore, independent of the level of differentiation-specific c-myc gene expression. However, after the induction of differentiation, a more internal territorial location was found for the single copy c-myc gene of normal chromosome 8, while amplicons conserved their territorial topography.

Primary Cell Cultures Arising from Normal Kidney and Renal Cell Carcinoma Retain the Proteomic Profile of Corresponding Tissues

Renal cell carcinoma (RCC) tissue is composed of a mixture of neoplastic and normal cells, which complicate proteome analysis. The aim of our study was to investigate whether it is feasible to establish primary cell cultures of RCC and of renal cortex maintaining the tissue phenotype along with a more homogeneous and enriched cytological material. Fourteen (82.3%) primary cultures from 17 surgical cases were established and characterized by morphology, growth rate, immunocytochemistry, and molecular analysis performed by Real-time PCR, Western blotting, two-dimensional electrophoresis (2-DE), and mass spectrometry. Cultures showed >90% cytokeratine-positive epithelial cells. In primary tumor cultures, the molecular phenotype of manganese superoxide dismutase and heat shock protein 27 was the same as that found in tumor tissues with overexpression and increased number of isoforms. Moreover, 27 out 28 specific proteins and their isoforms, present in spots excised from 2-DE gel of cortex or RCC cultures, corresponded to those identified on the 2-DE tissue cortex reference map, suggesting that these primary cultures retain the proteomic profile of the corresponding tissues.

Nuclear topography and expression of the BCR/ABL fusion gene and its protein level influenced by cell differentiation and RNA interference

Nuclear topography, expression of the BCR/ABL fusion gene and its protein level/cellular pattern were studied in CML cell line K562 stimulated to differentiation, apoptosis and influenced by ABL-RNA interference (ABL-RNAi). Phorbol ester-induced maturation of K562 cells was accompanied by repositioning of down-regulated BCR/ABL genes closer to the nuclear membrane. This nuclear rearrangement could be connected with differentiation-related heterochromatinization of the amplified BCR-ABL locus, as demonstrated by increased histone H3(K9) dimethylation and decreased H3(K9) acetylation of B3A2 breakpoint. Topography of BCR/ABL in differentiated K562 cells was compared with other leukemic cell types: PMA-maturation of HL60 cells did not influence the nuclear positioning of individual BCR and ABL genes. Moreover, BCR and ABL genes in non-stimulated HL60 as well as in the bone marrow cells of CML patients, i.e. also BCR/ABL fusion genes, were positioned more interiorly in comparison with BCR/ABL multiple loci of K562 cells. Decreased expression of BCR/ABL gene was also found after cell stimulation by selectively pro-apoptotic agent etoposide and by ABL-RNAi leading to apoptosis. In order to compare the efficiency of selected experimental strategies, levels of Bcr/Abl and c-Abl proteins were determined and in all cases tested were reduced. In K562 cells the Bcr/Abl and c-Abl proteins were distributed homogeneously in both the cell nucleus and cytoplasm, while differentiation of K562 cells was characterized by a distinct pattern of Bcr/Abl and c-Abl proteins that were focally distributed rather in the cytoplasm while apoptotic population was completely absent of Bcr/Abl and c-Abl signals.

N- and C-terminal isoforms of Arg quantified by real-time PCR are specifically expressed in human normal and neoplastic cells, in neoplastic cell lines, and in HL-60 cell differentiation

The human ABL2 (or ARG) gene codes for a nonreceptor tyrosine kinase is involved in translocation with the ETV6 gene in human leukemia and has an altered expression in several human carcinomas. Two isoforms of Arg with different N-termini (1A and 1B) have been described. The C-terminal domain of Arg contains two F-actin-binding sequences that perform a number of actions related to cell morphology and motility by interacting with actin filaments. We have identified different-sized specific cDNAs in hematopoietic, epithelial, nervous, and fibroblastic cells by means of the reverse transcription (RT)-polymerase chain reaction (PCR) analysis of human Arg mRNA. Some of these cDNAs showed an adjunctive alternative splice event involving the 63 bp sequence of exon II, thus leading to four cDNA types with different N-termini: 1A long and short, and 1B long and short. Other cDNAs lacked a 309 bp sequence in the last exon involving one of the C-terminal F-actin binding domains, thus giving rise to two cDNA types: C-termini long and short. Quantified by real-time PCR-quantitative RT-PCR-these Arg transcript isoforms have specific expression patterns not only in different normal and tumor cell types, but also during cell differentiation and growth arrest. These isoforms maintained the open reading frames, and eight putative proteins were predicted. The different C-termini isoforms seem to retain the same quantitative reciprocal ratio of their respective transcripts. The Arg protein isoforms with different C-terminal actin-binding domains and different N-termini might have specific cellular localizations/concentrations, and differently regulated catalytic activity with different implications in normal and neoplastic cells.

Nuclear topography of beta-like globin gene cluster in IL-3-stimulated human leukemic K-562 cells

The beta-like globin genes, Ggamma, Agamma, delta and beta, forming specific clusters on chromosome 11, are transcriptionally regulated by the locus control region (LCR). The members of beta-like globin gene cluster (11p15.4) are variously switched during ontogenetic dependent erythropoiesis; however, changes of globin gene expression can be also observed during erythroid differentiation of bone marrow cells. In our experiments, interleukin-3 (IL-3)-stimulated human leukemic K-562 cells were used as a model system in which nuclear organization and expression of the beta-like globin gene cluster was investigated. In addition, the influence of IL-3 on the arrangement of chromosome 11 territory was analyzed. We observed that the beta-globin gene is not expressed in progenitor (nondifferentiated) K-562 cells, but is, however, activated after IL-3 stimulation of the K-562 population. A similar nuclear location of beta-like globin gene clusters was found in both control and IL-3-treated cells, which indicates that changes in cluster gene expression are accompanied by conserved nuclear topography of the gene cluster studied. On the other hand, the studied type of cell differentiation was characterized by relocation of chromosome 11 and its centromeric regions closer to the nuclear periphery, which seems to be a general feature of many pathways of cellular maturation. The beta-like globin gene cluster was observed on chromatin loops extended away from compact chromosome 11 territories that were more condensed in regions closer to the nuclear membrane. The relocation of chromosome 11 territories towards the nuclear periphery and simultaneous appearance of chromatin loops may explain the conserved nuclear positioning of the gene cluster studied.

The expression of the non-receptor tyrosine kinases Arg and c-abl is differently modulated in B lymphoid cells at different stages of differentiation

The products of the human ARG gene and the human ABL gene characterize the Abelson family of non-receptor tyrosine protein kinases. Both genes are ubiquitously expressed. The interactions of these two similar protein kinases are still not well known, although it has been suggested that they could cooperate, with redundant actions, to provide intracellular signals in the cells. Lymphopenia occurs in mice with homozygous disruption of c-abl, indicating that in certain tissues Arg is unable to substitute c-abl functions. In B and T lymphoid cell lines at different stages of differentiation, we studied, by a reverse transcriptase-competitive polymerase chain reaction and Western blotting, Arg and c-abl in order to evaluate whether the expression pattern of the two genes could give insight as to why they do not exhibit overlapping roles in lymphocytes and whether the product levels of the two genes are related to lymphoid differentiation. The data showed that their expression is differently modified in lymphoid B cell lines. The highest Arg transcript and protein levels are in the mature B cells.

Drop of connexin 43 in replicative senescence of human fibroblasts HEL-299 as a possible biomarker of senescence

The expression of connexin 43 (cx43) and cell-cell communication were studied in replicative senescence of cultured HEL-299 fibroblasts. A progressive decrease in fluorescent dye transfer was detected by a scrape-loading technique in aging fibroblasts. This change was accounted for by a marked decrease in the amount of cx43 in aging cells, as detected by western blot analysis (cell extracts) and indirect fluorescence (cells in culture). However, semiquantitative RT-PCR assays of cx43 mRNA did not reveal appreciable changes, which suggests several possible explanations for the mechanism(s) underlying the decrease of cx43 in aging cells. These findings support the idea that the reduced expression of cx43 might be a biomarker of cell senescence.

Nuclear structure and gene activity in human differentiated cells

The nuclear arrangement of the ABL, c-MYC, and RB1 genes was quantitatively investigated in human undifferentiated HL-60 cells and in a terminally differentiated population of human granulocytes. The ABL gene was expressed in both cell types, the c-MYC gene was active in HL-60 cells and down-regulated in granulocytes, and expression of the RB1 gene was undetectable in HL-60 cells but up-regulated in granulocytes. The distances of these genes to the nuclear center (membrane), to the center of the corresponding chromosome territory, and to the nearest centromere were determined. During granulopoesis, the majority of selected genetic structures were repositioned closer to the nuclear periphery. The nuclear reposition of the genes studied did not correlate with the changes of their expression. In both cell types, the c-MYC and RB1 genes were located at the periphery of the chromosome territories regardless of their activity. The centromeres of chromosomes 8 and 13 were always positioned more centrally within the chromosome territory than the studied genes. Close spatial proximity of the c-MYC and RB1 genes with centromeric heterochromatin, forming the chromocenters, correlated with gene activity, although the nearest chromocenter of the silenced RB1 gene did not involve centromeric heterochromatin of chromosome 13 where the given gene is localized. In addition, the role of heterochromatin in gene silencing was studied in retinoblastoma cells. In these differentiated tumor cells, one copy of the RB1 gene was positioned near the heterochromatic chromosome X, and reduced RB1 gene activity was observed. In the experiments presented here, we provide evidence that the regulation of gene activity during important cellular processes such as differentiation or carcinogenesis may be realized through heterochromatin-mediated gene silencing.

Biomic study of human myeloid leukemia cells differentiation to macrophages using DNA array, proteomic, and bioinformatic analytical methods

A biomic approach by integrating three independent methods, DNA microarray, proteomics and bioinformatics, is used to study the differentiation of human myeloid leukemia cell line HL-60 into macrophages when induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Analysis of gene expression changes at the RNA level using cDNA against an array of 6033 human genes showed that 5950 (98.6%) of the genes were expressed in the HL-60 cells. A total of 624 genes (10.5%) were found to be regulated during HL-60 cell differentiation. Most of these genes have not been previously associated with HL-60 cells and include genes encoded for secreted proteins as well as genes involved in cell adhesion, signaling transduction, and metabolism. Protein analysis using two-dimensional gel electrophoresis showed a total of 682 distinct protein spots; 136 spots (19.9%) exhibited quantitative changes between HL-60 control and macrophages. These differentially expressed proteins were identified by mass spectrometry. We developed a bioinformatics program, the Bulk Gene Search System (BGSS, http://www.sinica.edu.tw:8900/perl/genequery.pl) to search for the functions of genes and proteins identified by cDNA microarrays and proteomics. The identified regulated proteins and genes were classified into seven groups according to subcellular locations and functions. This powerful holistic biomic approach using cDNA microarray, proteomics coupled to bioinformatics can provide in-depth information on the impact and importance of the regulated genes and proteins for HL-60 differentiation.

Polyamine oxidase activity in lymphoid tissues of glucocorticoid-treated rats

Glucocorticoids are known to negatively affect lymphoid tissues, in which they cause programmed cell death. Polyamine depletion, which occurs in glucocorticoid-treated animals by inhibition of biosynthesis and induction of acetylation, may represent a signal to thymocytes for progression into the apoptotic program. Since catalysis of polyamines by the catabolic pathway produces hydrogen peroxide as a by-product, it has been suggested that the apoptotic process may be, in part, due to oxidative stress as a result of hydrogen peroxide production. In order to verify whether polyamine oxidase (EC 1.5.3.11) may play a role in the process, we examined the activity of the enzyme in the thymus and spleen of glucocorticoid-treated rats. We administered dexamethasone (4 mg/kg) or two different doses of corticosterone (4 mg/kg or 30 mg/kg) to rats, which were killed 8 or 24 hr after hormone injection. We found that corticosterone and dexamethasone affected polyamine oxidase activity in both tissues, with an opposite dose-dependent effect of the natural hormone in the thymus. The decrease and increase in polyamine oxidase after the two doses of corticosterone were correlated with the absence and the occurrence of DNA fragmentation, respectively. Moreover, corticosterone affected polyamine oxidase activity earlier (8 hr) than dexamethasone (24 hr), but the synthetic hormone was more efficient than the natural hormone in thymic polyamine depletion. The polyamine oxidase response may represent an important event in lymphoid tissues after glucocorticoid treatment, suggesting a role of the enzyme in the catabolic effects exerted by the two hormones.