Anti-tumor effect of hematopoietic cells carrying the gene of ribonuclease inhibitor

Functional status analysis of RNH1 in bladder cancer for predicting immunotherapy response

Bladder cancer (BLCA) typically has a poor prognosis due to high rates of relapse and metastasis. Although the emergence of immunotherapy brings hope for patients with BLCA, not all patients will benefit from it. Identifying some markers to predict treatment response is particularly important. Here, we aimed to determine the clinical value of the ribonuclease/angiogenin inhibitor 1 (RNH1) in BLCA therapy based on functional status analysis. First, we found that RNH1 is aberrantly expressed in multiple cancers but is associated with prognosis in only a few types of cancer. Next, we determined that low RNH1 expression was significantly associated with enhanced invasion and metastasis of BLCA by assessing the relationship between RNH1 and 17 functional states. Moreover, we identified 95 hub genes associated with invasion and metastasis among RNH1-related genes. Enrichment analysis revealed that these hub genes were also significantly linked with immune activation. Consistently, BLCA can be divided into two molecular subtypes based on these hub genes, and the differentially expressed genes between the two subtypes are also significantly enriched in immune-related pathways. This indicates that the expression of RNH1 is also related to the tumour immune response. Subsequently, we confirmed that RNH1 shapes an inflammatory tumour microenvironment (TME), promotes activation of the immune response cycle steps, and has the potential to predict the immune checkpoint blockade (ICB) treatment response. Finally, we demonstrated that high RNH1 expression was significantly associated with multiple therapeutic signalling pathways and drug targets in BLCA. In conclusion, our study revealed that RNH1 could provide new insights into the invasion of BLCA and predict the immunotherapy response in patients with BLCA.

Concise Review: Pancreatic Cancer and Bone Marrow-Derived Stem Cells

Pancreatic adenocarcinoma remains one of the most challenging diseases of modern gastroenterology, and, even though considerable effort has been put into understanding its pathogenesis, the exact molecular mechanisms underlying the development and/or systemic progression of this malignancy still remain unclear. Recently, much attention has been paid to the potential role of bone marrow-derived stem cells (BMSCs) in this malignancy. Hence, herein, we comprehensively review the most recent discoveries and current achievements and concepts in this field. Specifically, we discuss the significance of identifying pancreatic cancer stem cells and novel therapeutic approaches involving molecular interference of their metabolism. We also describe advances in the current understanding of the biochemical and molecular mechanisms responsible for BMSC mobilization during pancreatic cancer development and systemic spread. Finally, we summarize experimental, translational, and/or clinical evidence regarding the contribution of bone marrow-derived mesenchymal stem cells, endothelial progenitor cells, hematopoietic stem/progenitor cells, and pancreatic stellate cells in pancreatic cancer development/progression. We also present their potential therapeutic value for the treatment of this deadly malignancy in humans.

SIGNIFICANCE

Different bone marrow-derived stem cell populations contribute to the development and/or progression of pancreatic cancer, and they might also be a promising "weapon" that can be used for anticancer treatments in humans. Even though the exact role of these stem cells in pancreatic cancer development and/or progression in humans still remains unclear, this concept continues to drive a completely novel scientific avenue in pancreatic cancer research and gives rise to innovative ideas regarding novel therapeutic modalities that can be safely offered to patients.

Radiogenic Therapy: Novel Approaches for Enhancing Tumor Radiosensitivity

Radiotherapy (RT) is a well established modality for treating many forms of cancer. However, despite many improvements in treatment planning and delivery, the total radiation dose is often too low for tumor cure, because of the risk of normal tissue damage. Gene therapy provides a new adjunctive strategy to enhance the effectiveness of RT, offering the potential for preferential killing of cancer cells and sparing of normal tissues. This specificity can be achieved at several levels including restricted vector delivery, transcriptional targeting and specificity of the transgene product. This review will focus on those gene therapy strategies that are currently being evaluated in combination with RT, including the use of radiation sensitive promoters to control the timing and location of gene expression specifically within tumors. Therapeutic transgenes chosen for their radiosensitizing properties will also be reviewed, these include:

gene correction therapy, in which normal copies of genes responsible for radiation-induced apoptosis are transfected to compensate for the deletions or mutated variants in tumor cells (p53 is the most widely studied example). enzymes that synergize the radiation effect, by generation of a toxic species from endogenous precursors ( e.g., inducible nitric oxide synthase) or by activation of non toxic prodrugs to toxic species ( e.g., herpes simplex virus thymidine kinase/ganciclovir) within the target tissue. conditionally replicating oncolytic adenoviruses that synergize the radiation effect. membrane transport proteins ( e.g., sodium iodide symporter) to facilitate uptake of cytotoxic radionuclides.

The evidence indicates that many of these approaches are successful for augmenting radiation induced tumor cell killing with clinical trials currently underway.

Killing of cancer cells through the use of eukaryotic expression vectors harbouring genes encoding nucleases and ribonuclease inhibitor

Cancer gene therapy vectors are promising tools for killing cancer cells with the purpose of eradicating malignant tumours entirely. Different delivery methods of vectors into the cancer cells, including both non-viral and viral, as well as promoters for the targeted expression of genes encoding anticancer proteins were developed for effective and selective killing of cancer cells without harming healthy cells. Many vectors have been created to kill cancer cells, and some vectors suppress malignant tumours with high efficiency. This review is focused on vectors bearing genes for nucleases such as deoxyribonucleases (caspase-activated DNase, deoxyribonuclease I-like 3, endonuclease G) and ribonucleases (human polynucleotide phosphorylase, ribonuclease L, α-sarcin, barnase), as well as vectors harbouring gene encoding ribonuclease inhibitor. The data concerning the functionality and the efficacy of such vectors are presented.

Stress granules, P-bodies and cancer

Cancer cells are exposed to adverse conditions in the tumor microenvironment, and utilize post-transcriptional control mechanisms to re-program gene expression in ways that enhance cell survival. Stress granules and processing bodies are RNA-containing granules that contribute to this process by modulating cellular signaling pathways, metabolic machinery, and stress response programs. This review examines evidence implicating RNA granules in the pathogenesis of cancer and discusses their potential as targets for anticancer therapies. This article is part of a Special Issue entitled: Translation and Cancer.

Overexpression of ribonuclease inhibitor defines good prognosis and suppresses proliferation and metastasis in human colorectal cancer cells via PI3K/AKT pathway

PURPOSE

We aim to evaluate the diagnostic value of ribonuclease inhibitor (RI) in colorectal cancer (CRC) and investigate the important role of RI in cell growth and metastasis of CRC.

METHODS/PATIENTS

In this study, the expression of RI was evaluated in human CRC samples with different histological grade and the association between RI expression and clinicopathological parameters was investigated. Furthermore, the exogenous RI gene was introduced into human HT29 CRC cells and the effects of RI on cell proliferation and metastasis were determined in vitro. The PI3K/Akt signaling pathway and some related protein molecules were detected.

RESULTS

RI is downregulated in CRC tissues compared to adjacent normal tissues and its expression is inversely associated with histological grade, pathological stage, and venous invasion, respectively. Multivariate analysis showed that RI expression was an independent prognostic factor for overall survival. In addition, the exogenous overexpression of RI reduced the proliferation and migration of HT29 CRC cell line in vitro by inhibiting the PI3K/Akt signaling pathway and suppressing the expression of vascular endothelial growth factor (VEGF) and upregulating phosphatase and tensin homolog (PTEN).

CONCLUSIONS

RI represents an important predictor of progression in patients with CRC and suppresses proliferation and metastasis in CRC cells through inhibiting PI3K/AkT pathway.

Angiogenin interacts with ribonuclease inhibitor regulating PI3K/AKT/mTOR signaling pathway in bladder cancer cells

Angiogenin (ANG), a member of RNase A superfamily, is the only angiogenic factor that possesses ribonucleolytic activity. Recent studies showed that the expression of ANG was elevated in various types of cancers. Accumulating evidence indicates that ANG plays an essential role in cancer progression by stimulating both cancer cell proliferation and tumor angiogenesis. Human ribonuclease inhibitor (RI), a cytoplasmic protein, is constructed almost entirely of leucine rich repeats (LRRs), which are present in a large family of proteins that are distinguished by their display of vast surface areas to foster protein-protein interactions. RI might be involved in unknown biological effects except inhibiting RNase A activity. The experiment demonstrated that RI also could suppress activity of angiogenin (ANG) through closely combining with it in vitro. PI3K/AKT/mTOR signaling pathway exerts a key role in cell growth, survival, proliferation, apoptosis and angiogenesis. We recently reported that up-regulating RI inhibited the growth and induced apoptosis of murine melanoma cells through repression of angiogenin and PI3K/AKT signaling pathway. However, ANG receptors have not yet been identified to date, its related signal transduction pathways are not fully clear and underlying interacting mechanisms between RI and ANG remain largely unknown. Therefore, we hypothesize that RI might combine with intracellular ANG to block its nuclear translocation and regulate PI3K/AKT/mTOR signaling pathway to inhibit biological functions of ANG. Here, we reported for the first time that ANG could interact with RI endogenously and exogenously by using co-immunoprecipitation (Co-IP) and GST pull-down. Furthermore, we observed the colocalization of ANG and RI in cells with immunofluorescence staining under laser confocal microscope. Moreover, through fluorescence resonance energy transfer (FRET) assay, we further confirmed that these two proteins have a physical interaction in living cells. Subsequently, we demonstrated that up-regulating ANG including ANG His37Ala mutant obviously decreased RI expression and activated phosphorylation of key downstream target molecules of PI3K/AKT/mTOR signaling pathway. Finally, up-regulating ANG led to the promotion of tumor angiogenesis, tumorigenesis and metastasis in vivo. Taken together, our data provided a novel mechanism of ANG in regulating PI3K/AKT/mTOR signaling pathway via RI, which suggested a new therapeutic target for cancer therapy.

Ribonuclease inhibitor up-regulation inhibits the growth and induces apoptosis in murine melanoma cells through repression of angiogenin and ILK/PI3K/AKT signaling pathway

Human ribonuclease inhibitor (RI), a cytoplasmic protein, is constructed almost entirely of leucine rich repeats. RI could suppress activities of ribonuclease and angiogenin (ANG) through closely combining with them. ANG is a potent inducer of blood vessel growth and has been implicated in the establishment, growth, and metastasis of tumors. ILK/PI3K/AKT signaling pathway also plays important roles in cell growth, cell-cycle progression, tumor angiogenesis, and cell apoptosis. Our previous experiments demonstrated that RI might effectively inhibit some tumor growth and metastasis. Our recent study showed that ILK siRNA inhibited the growth and induced apoptosis in bladder cancer cells as well as increased RI expression, which suggest a correlation between RI and ILK. However, the exact molecular mechanism of RI in anti-tumor and in the cross-talk of ANG and ILK signaling pathway remains largely unknown. Here we investigated the effects of up-regulating RI on the growth and apoptosis in murine melanoma cells through angiogenin and ILK/PI3K/AKT signaling pathway. We demonstrated that up-regulating RI obviously decreased ANG expression and activity. We also discovered that RI overexpression could remarkably inhibit cell proliferation, regulate cell cycle and induce apoptosis. Furthermore, up-regulation of RI inhibited phosphorylation of ILK downstream signaling targets protein kinase B/Akt, glycogen synthase kinase 3-beta (GSK-3β), and reduced β-catenin expression in vivo and vitro. More importantly, RI significant inhibited the tumor growth and angiogenesis of tumor bearing C57BL/6 mice. In conclusion, our findings, for the first time, suggest that angiogenin and ILK signaling pathway plays a pivotal role in mediating the inhibitory effects of RI on melanoma cells growth. This study identifies that RI may be a useful molecular target for melanoma therapy.

RETRACTED: Up-regulating ribonuclease inhibitor inhibited epithelial-to-mesenchymal transition and metastasis in murine melanoma cells

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The journal was notified about discrepancies in Figures 6C, 3C, 3E and 6A where a number of images had been inappropriately duplicated https://pubpeer.com/publications/16B7F676D60092A7A05400BE4DFE8E#3. Upon further investigation and discussion with the authors, insufficient evidence was provided to support a reasonable explanation for these discrepancies. As the concerns around these datasets are likely to affect the overall conclusions of the paper, the Editor-in-Chief has decided to retract the paper.

A novel sialyltransferase inhibitor suppresses FAK/paxillin signaling and cancer angiogenesis and metastasis pathways

Increased sialyltransferase (ST) activity promotes cancer cell metastasis, and overexpression of cell surface sialic acid correlates with poor prognosis in cancer patients. To seek therapies targeting metastasis for cancer treatment, we developed a novel ST inhibitor, Lith-O-Asp, and investigated its antimetastatic and antiangiogenic effects and mechanisms. We found that cells treated with Lith-O-Asp showed a reduction of activity on various ST enzymes by in vitro and cell-based activity analyses. Lith-O-Asp inhibited migration and invasion abilities in various cancer cell lines and showed inhibitory effect on the angiogenic activity of human umbilical vein endothelial cells. Indeed, Lith-O-Asp treatment consequently delayed cancer cell metastasis in experimental and spontaneous metastasis assays in animal models. Importantly, Lith-O-Asp decreased the sialic acid modification of integrin-β1 and inhibited the expression of phospho-FAK, phospho-paxillin, and the matrix metalloprotease (MMP) 2 and MMP9. Lith-O-Asp attenuated the Rho GTPase activity leading to actin dynamic impairment. In addition, 2DE-MS/MS and immunoblotting analyses showed that Lith-O-Asp altered the protein expression level and phosphorylation status of various proteins involved in crucial metastasis and angiogenesis pathways such as vimentin and ribonuclease/angiogenin inhibitor RNH1. Furthermore, Lith-O-Asp treatment significantly inhibited the invasive ability exerted by ectopic overexpression of various ST enzymes catalyzing α-2,6- or α-2,3-sialylation. Our results provide compelling evidence that the potential pan-ST inhibitor, Lith-O-Asp, suppressed cancer cell metastasis likely by inhibiting FAK/paxillin signaling and expressing antiangiogenesis factors. Lith-O-Asp is worthy for further testing as a novel antimetastasis drug for cancer treatment.

The role of mammalian ribonucleases (RNases) in cancer

Ribonucleases (RNases) are a group of enzymes that cleave RNAs at phosphodiester bonds resulting in remarkably diverse biological consequences. This review focuses on mammalian RNases that are capable of, or potentially capable of, cleaving messenger RNA (mRNA) as well as other RNAs in cells and play roles in the development of human cancers. The aims of this review are to provide an overview of the roles of currently known mammalian RNases, and the evidence that associate them as regulators of tumor development. The roles of these RNases as oncoproteins and/or tumor suppressors in influencing cell growth, apoptosis, angiogenesis, and other cellular hallmarks of cancer will be presented and discussed. The RNases under discussion include RNases from the conventional mRNA decay pathways, RNases that are activated under cellular stress, RNases from the miRNA pathway, and RNases with multifunctional activity.

Differential tissue-specific protein markers of vaginal carcinoma

The objective was to identify proteins differentially expressed in vaginal cancer to elucidate relevant cancer-related proteins. A total of 16 fresh-frozen tissue biopsies, consisting of 5 biopsies from normal vaginal epithelium, 6 from primary vaginal carcinomas and 5 from primary cervical carcinomas, were analysed using two-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry. Of the 43 proteins identified with significant alterations in protein expression between non-tumourous and tumourous tissue, 26 were upregulated and 17 were downregulated. Some were similarly altered in vaginal and cervical carcinoma, including cytoskeletal proteins, tumour suppressor proteins, oncoproteins implicated in apoptosis and proteins in the ubiquitin–proteasome pathway. Three proteins were uniquely altered in vaginal carcinoma (DDX48, erbB3-binding protein and biliverdin reductase) and five in cervical carcinoma (peroxiredoxin 2, annexin A2, sarcomeric tropomyosin kappa, human ribonuclease inhibitor and prolyl-4-hydrolase beta). The identified proteins imply involvement of multiple different cellular pathways in the carcinogenesis of vaginal carcinoma. Similar protein alterations were found between vaginal and cervical carcinoma suggesting common tumourigenesis. However, the expression level of some of these proteins markedly differs among the three tissue specimens indicating that they might be useful molecular markers.

In silico regulatory analysis for exploring human disease progression

Background

An important goal in bioinformatics is to unravel the network of transcription factors (TFs) and their targets. This is important in the human genome, where many TFs are involved in disease progression. Here, classification methods are applied to identify new targets for 152 transcriptional regulators using publicly-available targets as training examples. Three types of sequence information are used: composition, conservation, and overrepresentation.

Results

Starting with 8817 TF-target interactions we predict an additional 9333 targets for 152 TFs. Randomized classifiers make few predictions (~2/18660) indicating that our predictions for many TFs are significantly enriched for true targets. An enrichment score is calculated and used to filter new predictions.

Two case-studies for the TFs OCT4 and WT1 illustrate the usefulness of our predictions:

• Many predicted OCT4 targets fall into the Wnt-pathway. This is consistent with known biology as OCT4 is developmentally related and Wnt pathway plays a role in early development.

• Beginning with 15 known targets, 354 predictions are made for WT1. WT1 has a role in formation of Wilms' tumor. Chromosomal regions previously implicated in Wilms' tumor by cytological evidence are statistically enriched in predicted WT1 targets. These findings may shed light on Wilms' tumor progression, suggesting that the tumor progresses either by loss of WT1 or by loss of regions harbouring its targets.

• Targets of WT1 are statistically enriched for cancer related functions including metastasis and apoptosis. Among new targets are BAX and PDE4B, which may help mediate the established anti-apoptotic effects of WT1.

• Of the thirteen TFs found which co-regulate genes with WT1 (p ≤ 0.02), 8 have been previously implicated in cancer. The regulatory-network for WT1 targets in genomic regions relevant to Wilms' tumor is provided.

Conclusion

We have assembled a set of features for the targets of human TFs and used them to develop classifiers for the determination of new regulatory targets. Many predicted targets are consistent with the known biology of their regulators, and new targets for the Wilms' tumor regulator, WT1, are proposed. We speculate that Wilms' tumor development is mediated by chromosomal rearrangements in the location of WT1 targets.

Reviewers

This article was reviewed by Trey Ideker, Vladimir A. Kuznetsov(nominated by Frank Eisenhaber), and Tzachi Pilpel.

Protein unfolding in drug-RNase complexes

Bovine pancreatic ribonuclease A (RNase A) catalyzes the cleavage of P-O5' bonds in RNA on the 3' side of pyrimidine to form cyclic 2', 5'-phosphates. It has several high affinity binding sites that make it possible target for many organic and inorganic molecules. Ligand binding to RNase A can alter protein secondary structure and its catalytic activity. In this review, the effects of several drugs such as AZT (anti-AIDS), cis-Pt (antitumor), aspirin (anti-inflammatory), and vitamin C (antioxidant) on the stability and conformation of RNase A in vitro are compared. The results of UV-visible, FTIR, and CD spectroscopic analysis of RNase complexes with aspirin, AZT, cis-Pt, and vitamin C at physiological conditions are discussed here. Spectroscopic results showed one major binding for each drug-RNase adduct with KAZT=5.29 (+/-1.6)x10(4) M(-1), Kaspirin=3.57 (+/-1.4)x10(4) M(-1), Kcis-Pt=5.66 (+/-1.9)x10(3) M(-1), and Kascorbate=3.50 (+/-1.5)x10(3) M(-1). Major protein unfolding occurred with reduction of alpha-helix from 29% (free protein) to 20% and increase of beta-sheet from 39% (free protein) to 45% in the aspirin-, ascorbate-, and cis-Pt-RNase complexes, while minor increase of alpha-helix was observed for AZT-RNase adduct.

RNase A – tRNA binding alters protein conformation

Bovine pancreatic ribonuclease A (RNase A) catalyzes the cleavage of P-O5′ bonds in RNA on the 3′ side of pyrimidine to form cyclic 2′,5′-phosphates. Even though extensive structural information is available on RNase A complexes with mononucleotides and oligonucleotides, the interaction of RNase A with tRNA has not been fully investigated. We report the complexation of tRNA with RNase A in aqueous solution under physiological conditions, using a constant RNA concentration and various amounts of RNase A. Fourier transform infrared, UV-visible, and circular dichroism spectroscopic methods were used to determine the RNase binding mode, binding constant, sequence preference, and biopolymer secondary structural changes in the RNase–tRNA complexes. Spectroscopic results showed 2 major binding sites for RNase A on tRNA, with an overall binding constant of K = 4.0 × 105(mol/L)–1. The 2 binding sites were located at the G-C base pairs and the backbone PO2group. Protein–RNA interaction alters RNase secondary structure, with a major reduction in α helix and β sheets and an increase in the turn and random coil structures, while tRNA remains in the A conformation upon protein interaction. No tRNA digestion was observed upon RNase A complexation.

Cancer gene therapy targeting angiogenesis: An updated Review

Since the relationship between angiogenesis and tumor growth was established by Folkman in 1971, scientists have made efforts exploring the possibilities in treating cancer by targeting angiogenesis. Inhibition of angiogenesis growth factors and administration of angiogenesis inhibitors are the basics of anti-angiogenesis therapy. Transfer of anti-angiogenesis genes has received attention recently not only because of the advancement of recombinant vectors, but also because of the localized and sustained expression of therapeutic gene product inside the tumor after gene transfer. This review provides the up-to-date information about the strategies and the vectors studied in the field of anti-angiogenesis cancer gene therapy.

Complex Loci in human and mouse genomes

Mammalian genomes harbor a larger than expected number of complex loci, in which multiple genes are coupled by shared transcribed regions in antisense orientation and/or by bidirectional core promoters. To determine the incidence, functional significance, and evolutionary context of mammalian complex loci, we identified and characterized 5,248 cis-antisense pairs, 1,638 bidirectional promoters, and 1,153 chains of multiple cis-antisense and/or bidirectionally promoted pairs from 36,606 mouse transcriptional units (TUs), along with 6,141 cis-antisense pairs, 2,113 bidirectional promoters, and 1,480 chains from 42,887 human TUs. In both human and mouse, 25% of TUs resided in cis-antisense pairs, only 17% of which were conserved between the two organisms, indicating frequent species specificity of antisense gene arrangements. A sampling approach indicated that over 40% of all TUs might actually be in cis-antisense pairs, and that only a minority of these arrangements are likely to be conserved between human and mouse. Bidirectional promoters were characterized by variable transcriptional start sites and an identifiable midpoint at which overall sequence composition changed strand and the direction of transcriptional initiation switched. In microarray data covering a wide range of mouse tissues, genes in cis-antisense and bidirectionally promoted arrangement showed a higher probability of being coordinately expressed than random pairs of genes. In a case study on homeotic loci, we observed extensive transcription of nonconserved sequences on the noncoding strand, implying that the presence rather than the sequence of these transcripts is of functional importance. Complex loci are ubiquitous, host numerous nonconserved gene structures and lineage-specific exonification events, and may have a cis-regulatory impact on the member genes.

Inhibition of B16 Melanoma Growth in vivo by Retroviral Vector-Mediated Human Ribonuclease Inhibitor

Human ribonuclease inhibitor (hRI) can inhibit angiogenesis by reversibly binding angiogenin, a member of the RNaseA superfamily, and by suppressing the expression of basic fibroblast growth factor (bFGF). Angiogenesis is necessary for the growth and metastasis of tumors. To study the links between hRI, angiogenesis, and melanoma growth, the hRI gene was intravenously administered to mice in a recombinant retroviral vector, and expression of the hRI gene was induced to block melanoma angiogenesis. Expression, distribution, and contribution of the target gene in mice were assayed. The results showed that the tumors of mice in the hRI treatment group grew slower with less vascularity than those of mice in control groups. The introduced hRI gene inhibited tumor growth without causing significant side effects in the animals. More hRI expression in vimentin-positive cells of the tumor than in melanoma cells suggested that mesenchymal cells in the fibrous envelope of the tumor play important roles in this gene therapy.