Cancer Incidence After Diagnosis of Abdominal Aortic Aneurysm.

BACKGROUND: Epidemiological and mechanistic data support a potential causal link between cardiovascular disease (CVD) and cancer. Abdominal aortic aneurysms (AAAs) represent a common form of CVD with at least partially distinct genetic and biologic etiology from other forms of CVD. The risk of cancer and how this risk differs compared with other forms of CVD, is unknown among AAA patients. We conducted a retrospective cohort study using the IBM MarketScan Research Database to test whether individuals with AAA have a higher cancer risk independent of traditional shared risk factors. METHODS: All individuals ≥18 years of age with ≥36 months of continuous coverage between 2008 and 2020 were enrolled. Those with potential Mendelian etiologies of AAA, aortic aneurysm with nonspecific anatomic location, or a cancer diagnosis before the start of follow-up were excluded. A subgroup analysis was performed of individuals having the Health Risk Assessment records including tobacco use and body mass index. The following groups of individuals were compared: (1) with AAA, (2) with non-AAA CVD, and (3) without any CVD. RESULTS: The propensity score-matched cohort included 58 993 individuals with AAA, 117 986 with non-AAA CVD, and 58 993 without CVD. The 5-year cumulative incidence of cancer was 13.1% (12.8%-13.5%) in participants with AAA, 10.1% (9.9%-10.3%) in participants with non-AAA CVD, and 9.6% (9.3%-9.9%) in participants without CVD. Multivariable-adjusted Cox proportional hazards regression models found that patients with AAA exhibited a higher cancer risk than either those with non-AAA CVD (hazard ratio, 1.28 [95% CI, 1.23-1.32]; P<0.001) or those without CVD (hazard ratio, 1.32 [95% CI, 1.26-1.38]; P<0.001). Results remained consistent after excluding common smoking-related cancers and when adjusting for tobacco use and body mass index. CONCLUSIONS: Patients with AAA may have a unique risk of cancer requiring further mechanistic study and investigation of the role of enhanced cancer screening.

Role of vascular smooth muscle cell clonality in atherosclerosis.

Atherosclerotic cardiovascular disease remains the leading cause of death worldwide. While many cell types contribute to the growing atherosclerotic plaque, the vascular smooth muscle cell (SMC) is a major contributor due in part to its remarkable plasticity and ability to undergo phenotype switching in response to injury. SMCs can migrate into the fibrous cap, presumably stabilizing the plaque, or accumulate within the lesional core, possibly accelerating vascular inflammation. How SMCs expand and react to disease stimuli has been a controversial topic for many decades. While early studies relying on X-chromosome inactivation were inconclusive due to low resolution and sensitivity, recent advances in multi-color lineage tracing models have revitalized the concept that SMCs likely expand in an oligoclonal fashion during atherogenesis. Current efforts are focused on determining whether all SMCs have equal capacity for clonal expansion or if a "stem-like" progenitor cell may exist, and to understand how constituents of the clone decide which phenotype they will ultimately adopt as the disease progresses. Mechanistic studies are also beginning to dissect the processes which confer cells with their overall survival advantage, test whether these properties are attributable to intrinsic features of the expanding clone, and define the role of cross-talk between proliferating SMCs and other plaque constituents such as neighboring macrophages. In this review, we aim to summarize the historical perspectives on SMC clonality, highlight unanswered questions, and identify translational issues which may need to be considered as therapeutics directed against SMC clonality are developed as a novel approach to targeting atherosclerosis.

Silencing LY6D Expression Inhibits Colon Cancer in Xenograft Mice and Regulates Colon Cancer Stem Cells' Proliferation, Stemness, Invasion, and Apoptosis via the MAPK Pathway.

This study explored the role of lymphocyte antigen 6 family member D (LY6D) in colon cancer stem cells' (CCSCs) proliferation and invasion. LY6D was knocked down using siRNA, and the down-regulation of LY6D was verified using Western blotting. After LY6D knockdown, CCSCs' proliferation, stemness, and invasion were suppressed, whereas apoptosis was increased. Gene Ontology (GO) enrichment analysis revealed that the differentially expressed genes (DEGs) between siLY6D and the negative control groups were significantly enriched in the cell-substrate adherens junction, focal adhesion, and cell-substrate junction terms. Meanwhile, the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the DEGs were significantly enriched in the MAPK pathway. In addition, Western blotting results showed that pBRAF and pERK1/2, cascade kinases of the MAPK pathway, were significantly down-regulated after LY6D knockdown. In addition, nude mice xenograft experiments showed that the siLY6D treatment decreased tumor sizes and weights and improved tumor-bearing mice survival rates compared with the control group. In conclusion, these findings indicate that LY6D, which is highly expressed in CCSCs, is a key factor involved in tumor growth and development and might be a potential cancer marker and therapeutic target for colon cancer.

LncRNA Osilr9 coordinates promoter DNA demethylation and the intrachromosomal loop structure required for maintaining stem cell pluripotency.

Nuclear reprogramming of somatic cells into a pluripotent status has the potential to create patient-specific induced pluripotent stem cells for regenerative medicine. Currently, however, the epigenetic mechanisms underlying this pluripotent reprogramming are poorly understood. To delineate this epigenetic regulatory network, we utilized a chromatin RNA in situ reverse transcription sequencing (CRIST-seq) approach to identify long noncoding RNAs (lncRNAs) embedded in the 3-dimensional intrachromosomal architecture of stem cell core factor genes. By combining CRIST-seq and RNA sequencing, we identified Oct4-Sox2 interacting lncRNA 9 (Osilr9) as a pluripotency-associated lncRNA. Osilr9 expression was associated with the status of stem cell pluripotency in reprogramming. Using short hairpin RNA (shRNA) knockdown, we showed that this lncRNA was required for the optimal maintenance of stem cell pluripotency. Overexpression of Osilr9 induced robust activation of endogenous stem cell core factor genes in fibroblasts. Osilr9 participated in the formation of the intrachromosomal looping required for the maintenance of pluripotency. After binding to the Oct4 promoter, Osilr9 recruited the DNA demethylase ten-eleven translocation 1, leading to promoter demethylation. These data demonstrate that Osilr9 is a critical chromatin epigenetic modulator that coordinates the promoter activity of core stem cell factor genes, highlighting the critical role of pluripotency-associated lncRNAs in stem cell pluripotency and reprogramming.

Chromatin lncRNA Platr10 controls stem cell pluripotency by coordinating an intrachromosomal regulatory network.

BACKGROUND: A specific 3-dimensional intrachromosomal architecture of core stem cell factor genes is required to reprogram a somatic cell into pluripotency. As little is known about the epigenetic readers that orchestrate this architectural remodeling, we used a novel chromatin RNA in situ reverse transcription sequencing (CRIST-seq) approach to profile long noncoding RNAs (lncRNAs) in the Oct4 promoter. RESULTS: We identify Platr10 as an Oct4 - Sox2 binding lncRNA that is activated in somatic cell reprogramming. Platr10 is essential for the maintenance of pluripotency, and lack of this lncRNA causes stem cells to exit from pluripotency. In fibroblasts, ectopically expressed Platr10 functions in trans to activate core stem cell factor genes and enhance pluripotent reprogramming. Using RNA reverse transcription-associated trap sequencing (RAT-seq), we show that Platr10 interacts with multiple pluripotency-associated genes, including Oct4, Sox2, Klf4, and c-Myc, which have been extensively used to reprogram somatic cells. Mechanistically, we demonstrate that Platr10 helps orchestrate intrachromosomal promoter-enhancer looping and recruits TET1, the enzyme that actively induces DNA demethylation for the initiation of pluripotency. We further show that Platr10 contains an Oct4 binding element that interacts with the Oct4 promoter and a TET1-binding element that recruits TET1. Mutation of either of these two elements abolishes Platr10 activity. CONCLUSION: These data suggest that Platr10 functions as a novel chromatin RNA molecule to control pluripotency in trans by modulating chromatin architecture and regulating DNA methylation in the core stem cell factor network.

Therapeutic Antitumor Efficacy of Cancer Stem Cell-Derived DRibble Vaccine on Colorectal Carcinoma.

Dendritic cell (DC)-based immunotherapy has been a promising strategy for colon cancer therapy, but the efficacy of dendritic cell vaccines is in part limited by immunogenicity of loaded antigens. In this study, we aimed to identify a putative tumor antigen that can generate or enhance anti-tumor immune responses against colon cancer. CD44+ colon cancer stem cells (CCSCs) were isolated from mouse colorectal carcinoma CT-26 cell cultures and induced to form defective ribosomal products-containing autophagosome-rich blebs (DRibbles) by treatment with rapamycin, bortezomib, and ammonium chloride. DRibbles were characterized by western blot and transmission electron microscopy. DCs generated from the mice bone marrow monocytes were cocultured with DRibbles, then surface markers of DCs were analyzed by flow cytometry. Meanwhile, the efficacy of DRibble-DCs was examined in vivo. Our results showed that CCSC-derived DRibbles upregulated CD80, CD86, major histocompatibility complex (MHC)-I, and MHC-II on DCs and induced proliferation of mouse splenic lymphocytes and CD8+ T cells. In a model of colorectal carcinoma using BALB/c mice with robust tumor growth and mortality, DC vaccine pulsed with CCSC-derived DRibbles suppressed tumor growth and extended survival. A lactate dehydrogenase test indicated a strong cytolytic activity of cytotoxic T-cells derived from mice vaccinated with CCSC-derived DRibbles against CT-26 cells. Furthermore, flow cytometry analyses showed that the percentages of IFN-γ-producing CD8+ T-cells were increased in SD-DC group compare with the other groups. These findings provide a rationale for novel immunotherapeutic anti-tumor approaches based on DRibbles derived from colon cancer stem cells.

[Retracted] Synthetic miR­145 mimic inhibits multiple myeloma cell growth in vitro and in vivo.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that certain of the flow cytometric and western blotting data shown in Fig. 3A and C respectively, and the tumor images shown in Fig. 7A, bore unexpected similarities to data appearing in different form in other articles by different authors. Owing to the fact that some of the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they agreed with the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [the original article was published in Oncology Reports 33: 448-456, 2015; DOI: 10.3892/or.2014.3591].

Efficacy of atovaquone on EpCAM+CD44+ HCT-116 human colon cancer stem cells under hypoxia.

Tumor hypoxia contributes to the development of resistance to chemotherapeutic drugs in several human cancer cell lines. Atovaquone, an anti-malaria drug approved by the US Food and Drug Administration, has recently demonstrated anti-cancer effects in vitro and in vivo in several cancer models. To assess the potential of atovaquone as an anti-cancer agent under hypoxia in colorectal carcinoma, EpCAM+CD44+ colon cancer stem cells were isolated from HCT-116 human colon cancer cells through magnetic-activated cell sorting. The efficacy of atovaquone on cytotoxicity, tumorsphere formation, apoptosis, invasion and cell-cycle progression under hypoxic conditions were evaluated. MTS assays indicated that atovaquone inhibited the proliferation of EpCAM+CD44+ HCT-116 cells with a half-maximal inhibitory concentration of 15 µM. Atovaquone inhibited tumorsphere formation and cell proliferation by causing cell-cycle arrest in S-phase, which induced apoptosis of EpCAM+CD44+ HCT-116 cells, as detected by Annexin V-FITC/PI double staining assays, and caused mitochondrial membrane potential depolarization, as determined by a JC-1 staining assay. Reverse transcription-quantitative PCR demonstrated increased expression of Bax and downregulation of Bcl-2. Transwell invasion assays indicated that atovaquone inhibited the invasiveness of EpCAM+CD44+ HCT-116 cells under hypoxia, which was associated with upregulation of MMP-2 and -9 and increased expression of tissue inhibitor of MMPs (TIMP)-1. Taken together, atovaquone reduced the tumorsphere formation and invasion ability of EpCAM+CD44+ HCT-116 cells, at least in part by increasing the expression of TIMP-1 and downregulating the expression of MMP-2 and -9, as well as the cells' viability by inducing cell-cycle arrest in S-phase and induction of apoptosis via the Bcl-2/Bax pathway under hypoxic conditions. Further studies are warranted to explore the mechanisms of action of atovaquone as a promising anticancer agent in the treatment of colorectal carcinoma.

Osblr8 orchestrates intrachromosomal loop structure required for maintaining stem cell pluripotency.

Induced pluripotent stem cells (iPSCs), derived from reprogramming of somatic cells by a cocktail of transcription factors, have the capacity for unlimited self-renewal and the ability to differentiate into all of cell types present in the body. iPSCs may have therapeutic potential in regenerative medicine, replacing injured tissues or even whole organs. In this study, we examine epigenetic factors embedded in the specific 3-dimensional intrachromosomal architecture required for the activation of endogenous pluripotency genes. Using chromatin RNA in situ reverse transcription sequencing (CRIST-seq), we identified an Oct4-Sox2 binding long noncoding RNA, referred as to Osblr8, that is present in association with pluripotency status. Osblr8 was highly expressed in iPSCs and E14 embryonic stem cells, but it was silenced in fibroblasts. By using shRNA to knock down Osblr8, we found that this lncRNA was required for the maintenance of pluripotency. Overexpression of Osblr8 activated endogenous stem cell core factor genes. Mechanistically, Osblr8 participated in the formation of an intrachromosomal looping structure that is required to activate stem cell core factors during reprogramming. In summary, we have demonstrated that lncRNA Osblr8 is a chromatin architecture modulator of pluripotency-associated master gene promoters, highlighting its critical epigenetic role in reprogramming.

Dendritic cells loaded with CD44+ CT-26 colon cell lysate evoke potent antitumor immune responses.

Increasing evidence supports the concept that cancer stem cells (CSCs) are responsible for cancer progression and metastasis, therapy resistance and relapse. In addition to conventional therapies for colon cancer, the development of immunotherapies targeting cancer stem cells appears to be a promising strategy to suppress tumor recurrence and metastasis. In the present study, dendritic cells (DCs) were pulsed with whole-tumor cell lysates or total RNA of CD44+ colon cancer stem cells (CCSCs) isolated from mouse colon adenocarcinoma CT-26 cell cultures and investigated for their antitumor immunity against CCSCs in vivo and in vitro. In a model of colon adenocarcinoma using BALB/c mice, a sequential reduction in tumor volume and weight was associated with an extended survival in tumor-bearing mice vaccinated with DCs pulsed with RNA or CCSC lysate. In addition, a lactate dehydrogenase assay indicated that cytotoxic T-cells derived from the treated mice exhibited strong cytotoxic activity. Additionally, an enzyme-linked immunosorbent assay revealed that the cytotoxic T-cells of the treated mice released higher levels of interferon-γ against CCSCs compared with those of the control group. In all experiments, the antitumor efficacy of the lysate-pulsed DC-treated and RNA-pulsed DC-treated groups were significantly higher compared with that of the DC-treated and control groups. The results of the present study indicated the potential use of DCs pulsed with cancer stem cell lysates as a potent therapeutic antigen to target CSCs in colon cancer. Additionally, the results provided a rationale for using lysate-pulsed DCs in vivo to eliminate residual tumor deposits in post-operative patients.

Enhanced anticancer effect of oncostatin M combined with salinomycin in CD133+ HepG2 liver cancer cells.

Oncostatin M (OSM) induces the differentiation of liver cancer stem cells (LCSCs) and increases sensitivity to the chemotherapeutic agent 5-fluorouracil, whereas salinomycin (Sal) induces apoptosis in cancer stem cells and inhibits the proliferation of liver cancer cells. However, there have been no studies investigating the anticancer effects of combination treatment with OSM and Sal. In the present study, we investigated the synergistic effects of OSM and Sal on LCSCs, the CD133+ subpopulations from HepG2 human liver cancer cells. CD133+ LCSCs were isolated using an immunomagnetic bead technique and identified through colony formation. After incubating with OSM and Sal, the ability of LCSC proliferation and invasion, as well as apoptosis rates were evaluated, and the expression of stemness-related genes was examined by quantitative real-time polymerase chain reaction. Additionally, the secretion of α-fetoprotein (AFP) and albumin (ALB) were analyzed by enzyme-linked immunosorbent assay. Our results indicated that OSM combined with Sal significantly suppressed LCSC proliferation and invasion and induced apoptosis, as determined by flow cytometry and increases in cleaved caspase-3 levels detected by western blotting. The results of the JC-1 staining assay indicated that this effect involved the mitochondrial pathway. Moreover, combination treatment reduced the expression of CD133 in LCSCs and suppressed stemness-related gene expression. Furthermore, the LCSCs produced lower levels of AFP and higher levels of ALB following combination treatment. In all experiments, combination treatment elicited more efficient anticancer effects on LCSCs as compared with single-drug treatment; therefore, our results demonstrated that combined treatment with OSM and Sal inhibited proliferation and induced differentiation and apoptosis in LCSCs, suggesting combined use of OSM and Sal as a therapeutic strategy for liver cancer.

Protection against influenza A virus by vaccination with a recombinant fusion protein linking influenza M2e to human serum albumin (HSA).

The highly conserved extracellular domain of M2 protein (M2e) of influenza A viruses has limited immunogenicity on its own. Hence, aiming to enhance immunogenicity of M2e protein, optimal approaches remain to be established. In this study, we created recombinant fusion protein vaccines by linking M2e consensus sequence of influenza A viruses with C-terminal domain of human serum albumin (HSA). Then HSA/M2e recombinant fusion protein was studied. Our results showed that HSA/M2e could induce strong anti-M2e specific humoral immune responses in the established mice model. Administration of HSA/M2e with Freund's adjuvant resulted in a higher number of IFN-γ-producing cells compared to HSA/M2e or M2e peptide emulsified in Freund's adjuvant. Furthermore, HSA/M2e was able to reduce viral load in the mice lungs and provide significant protection against lethal challenge with an H1N1 or an H3N2 virus compared to controls. In conclusion, this study has demonstrated a potential vaccine that could provide protection in preventing the threat of influenza outbreak because of rapid variation of the influenza virus.

Salinomycin inhibits the growth of colorectal carcinoma by targeting tumor stem cells.

Salinomycin is a monocarboxylic polyether antibiotic that has been reported to induce apoptosis in various types of cancer cells with specificity for cancer stem cells. However, its anticancer effect in colorectal cancer stem cells has never been reported. In the present study, we examined the ability of salinomycin to induce cell death in the colorectal cancer stem cell line CD44+EpCAM+ HCT-116, and we measured its in vivo tumor inhibition capacity. Salinomycin dose-dependently induced cytotoxicity in the CD44+EpCAM+ HCT-116 cells and inhibited colony formation. Salinomycin treatment was shown to induce apoptosis, as evidenced by nuclear fragmentation, an increase in the proportion of acridine orange/ethidium bromide-positive cells and an increase in the percentage of Annexin V-positive cells. Apoptosis was induced in colorectal cancer stem cells in a caspase-dependent manner, as shown by an increase in the levels of cleaved caspase-3, -8 and -9. JC-1 staining further revealed that salinomycin induced colorectal cancer cell apoptosis via the mitochondrial pathway. In addition, salinomycin treatment of xenograft mice inhibited the growth of tumors derived from the CD44+EpCAM+ HCT-116 cells. The present study demonstrated that the antibiotic salinomycin exerts an anti-colorectal cancer effect in vitro and in vivo, suggesting salinomycin as a potential drug for colorectal cancer therapy.

The Histone Acetyltransferase MOF Promotes Induces Generation of Pluripotent Stem Cells.

Histone modification plays an important role in maintaining pluripotency and self-renewal of embryonic stem cells (ESCs). The histone acetyltransferase MOF is a key regulator of ESCs; however, the role of MOF in the process of reprogramming back to induced pluripotent stem cells (iPSCs) remains unclear. In this study, we investigated the function of MOF on the generation of iPSCs. We show that iPSCs contain high levels of MOF mRNA, and the expression level of MOF protein is dramatically upregulated following reprogramming. Most importantly, overexpression of MOF improves reprogramming efficiency and facilitates the formation of iPSCs, whereas small hairpin RNA (shRNA)-mediated knockdown of MOF impairs iPSCs generation during reprogramming. Further investigation reveals that MOF interacts with the H3K4 methyltransferase Wdr5 to promote endogenous Oct4 expression during the reprogramming process. Knockdown of MOF reduces H4K16ac and H3K4me3 modification at the Oct4 promoter. In conclusion, our data indicate that MOF is an important epigenetic regulator that is critical for efficient reprogramming.

Isolation, identification and differentiation of human embryonic cartilage stem cells.

We isolated human embryonic cartilage stem cells (hECSCs), a novel stem cell population, from the articular cartilage of eight-week-old human embryos. These stem cells demonstrated a marker expression pattern and differentiation potential intermediate to those of human embryonic stem cells (hESCs) and human adult stem cells (hASCs). hECSCs expressed markers associated with both hESCs (OCT4, NANOG, SOX2, SSEA-3 and SSEA-4) and human adult stem cells (hASCs) (CD29, CD44, CD90, CD73 and CD10). These cells also differentiated into adipocytes, osteoblasts, chondrocytes, neurons and islet-like cells under specific inducing conditions. We identified N(6), 2'-O-dibutyryl cyclic adenosine 3':5'-monophosphate (Bt2cAMP) as an inducer of chondrogenic differentiation in hECSCs. Similar results using N(6), 2'-O-dibutyryl cyclic adenosine 3':5'-monophosphate (Bt2cAMP) were obtained for two other types of human embryonic tissue-derived stem cells, human embryonic hepatic stem cells (hEHSCs) and human embryonic amniotic fluid stem cells (hEASCs), both of which exhibited a marker expression pattern similar to that of hECSCs. The isolation of hECSCs and the discovery that N(6), 2'-O-dibutyryl cyclic adenosine 3':5'-monophosphate (Bt2cAMP) induces chondrogenic differentiation in different stem cell populations might aid the development of strategies in tissue engineering and cartilage repair.

Synthetic miR-145 mimic inhibits multiple myeloma cell growth in vitro and in vivo.

Multiple myeloma (MM) is a disease with an adverse outcome and new therapeutic strategies are required to combat this disease. It is well known that tumor­suppressor microRNA (miRNA) acts as a new potential anticancer agent. Accumulating evidence showed that microRNA-145 (miR-145) is a candidate tumor suppressor miRNA. However, whether miR-145 is involved in the development and progression of MM reamins to be determined. In the present study, we investigated the therapeutic potential of synthetic miR-145 against human MM cells in vitro and in vivo. The results showed that miR-145 was reduced in MM tissues and cell lines. Enforced expression of miR-145 by transfection with miR-145 mimics inhibited cell proliferation, migration, and the invasion abilities of H929 cells. Furthermore, our results demonstrated that the enforced expression of miR-145 in H929 cells profoundly decreased the levels of p-AKT and p-PI3K, which may contribute to some extent to the inhibition of MM cell proliferation and survival. The enforced expression of miR-145 in a xenograft mouse model suppressed tumor growth. In conclusion, our findings suggested that miR-145 may act as a tumor suppressor and contributes to the progression of MM. Additionally, miR-145 mimics is a potential therapeutic agent for the treatment of MM.