Induced pluripotent stem cells (iPSCs) can be generated from differentiated human and mouse somatic cells using transcription factors such as Oct4, Sox2, Klf4, and c-Myc. It is possible to augment ...the reprogramming process with chemical compounds, but issues related to low reprogramming efficiencies and, with a number of protocols, residual vector sequences, remain to be resolved. We show here that it is possible to reprogram mouse and human cells to pluripotency by direct transfection of mature double-stranded microRNAs (miRNAs). Our approaches use a combination of mir-200c plus mir-302 s and mir-369 s family miRNAs. Because this reprogramming method does not require vector-based gene transfer, it holds significant potential for biomedical research and regenerative medicine.
► Transfected mature miRNAs can reprogram mouse somatic cells to pluripotency ► A combination of mir-200c plus mir-302 s and mir-369 s family miRNAs is required ► miRNA-generated mi-iPSCs show all characteristics of pluripotency ► The same combination of miRNAs can also reprogram human somatic cells
Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway that coactivate large tumor suppressor homolog (LATS) kinases. Mob1a/1b double deficiency in mouse liver (LMob1DKO) ...results in hyperplasia of oval cells and immature cholangiocytes accompanied by inflammatory cell infiltration and fibrosis. More than half of mutant mice die within 3 wk of birth. All survivors eventually develop liver cancers, particularly combined hepatocellular and cholangiocarcinomas (cHC-CCs) and intrahepatic cholangiocellular carcinomas (ICCs), and die by age 60 wk. Because this phenotype is the most severe among mutant mice lacking a Hippo signaling component, MOB1A/1B constitute the critical hub of Hippo signaling in mammalian liver. LMob1DKO liver cells show hyperproliferation, increased cell saturation density, hepatocyte dedifferentiation, enhanced epithelial–mesenchymal transition and cell migration, and elevated transforming growth factor beta(TGF-β)2/3 production. These changes are strongly dependent on Yes-Associated Protein-1 (Yap1) and partially dependent on PDZ-binding motif (Taz) and Tgfbr2, but independent of connective tissue growth factor (Ctgf). In human liver cancers, YAP1 activation is frequent in cHC-CCs and ICCs and correlates with SMAD family member 2 activation. Drug screening revealed that antiparasitic macrocyclic lactones inhibit YAP1 activation in vitro and in vivo. Targeting YAP1/TAZ with these drugs in combination with inhibition of the TGF-β pathway may be effective treatment for cHC-CCs and ICCs.
Gastric cancer (GC) is one of the most lethal malignant tumors. To improve the prognosis of GC, the identification of novel driver genes as therapeutic targets is in urgent need. Here, we aimed to ...identify novel driver genes and clarify their roles in gastric cancer. OSBPL3 was identified as a candidate driver gene by in silico analysis of public genomic datasets. OSBPL3 expression was analyzed by RT-qPCR and immunohistochemistry in GC cells and tissues. The biological functions and mechanisms of OSBPL3 in GC were examined in vitro and in vivo using GC cells. The association between OSBPL3 expression and clinical outcome in GC patients was also evaluated. Overexpression of OSBPL3 was detected in GC cells with OSBPL3 DNA copy number gains and promoter hypomethylation. OSBPL3-knockdown reduced GC cell growth in vitro and in vivo by inhibiting cell cycle progression. Moreover, an active Ras pull-down assay and western blotting demonstrated that OSBPL3 activates the R-Ras/Akt signaling pathway in GC cells. In a clinical analysis of two GC datasets, high OSBPL3 expression was predictive of a poor prognosis. Our findings suggest that OSBPL3 is a novel driver gene stimulating the R-Ras/Akt signaling pathway and a potential therapeutic target in GC patients.
Microtubules are among the most successful targets for anticancer therapy because they play important roles in cell proliferation as they constitute the mitotic spindle, which is critical for ...chromosome segregation during mitosis. Hence, identifying new therapeutic targets encoding proteins that regulate microtubule assembly and function specifically in cancer cells is critical. In the present study, we identified a candidate gene that promotes tumor progression, ribonucleic acid export 1 (RAE1), a mitotic checkpoint regulator, on chromosome 20q through a bioinformatics approach using datasets of colorectal cancer (CRC), including The Cancer Genome Atlas (TCGA). RAE1 was ubiquitously amplified and overexpressed in tumor cells. High expression of RAE1 in tumor tissues was positively associated with distant metastasis and was an independent poor prognostic factor in CRC. In vitro and in vivo analysis showed that RAE1 promoted tumor growth, inhibited apoptosis, and promoted cell cycle progression, possibly with a decreased proportion of multipolar spindle cells in CRC. Furthermore, RAE1 induced chemoresistance through its anti–apoptotic effect. In addition, overexpression of RAE1 and significant effects on survival were observed in various types of cancer, including CRC. In conclusion, we identified RAE1 as a novel gene that facilitates tumor growth in part by inhibiting apoptosis and promoting cell cycle progression through stabilizing spindle bipolarity and facilitating tumor growth. We suggest that it is a potential therapeutic target to overcome therapeutic resistance of CRC.
In vitro and in vivo analysis showed that RAE1 promoted tumor growth and inhibited apoptosis of tumor cells, possibly with a decreased proportion of multipolar spindle cells in CRC. Furthermore, RAE1 induced chemoresistance through its anti–apoptotic effect. In conclusion, we identified RAE1 as a novel driver gene that inhibits apoptosis by stabilizing spindle bipolarity and facilitating tumor growth.
Purpose
Recent evidence has shown that altered patterns of microRNA (miRNA) expression correlate with various human cancers. We investigated the clinical significance of
miR-10b
and its involvement ...in chemotherapeutic resistance to 5-fluorouracil (5-FU), which is a key component of common chemotherapy regimens in colorectal cancer.
Methods
Quantitative RT-PCR was used to evaluate the clinicopathologic significance of
miR-10b
expression in 88 colorectal cancer cases. We also investigated the chemotherapeutic sensitivity to 5-FU in
miR-10b
-overexpressing colorectal cancer cells. To explore the mechanism of chemoresistance in
miR-10b
transfected cells, we examined whether
miR-10b
inhibits the pro-apoptotic BH3-only Bcl-2 family member
BIM
(
BCL2L11
), a key mediator of chemotherapy-induced cell death.
Results
High level
miR-10b
expression was found to be significantly associated with high incidence of lymphatic invasion (
P
= 0.0257) and poor prognosis (
P
= 0.0057). Multivariate analysis indicated that high
miR-10b
expression is an independent prognostic factor for survival. In vitro studies revealed that
miR-10b
directly inhibits pro-apoptotic
BIM
, and the overexpression of
miR-10b
confers chemoresistance in colorectal cancer cells to 5-FU.
Conclusions
MiR-10b
is a novel prognostic marker in colorectal cancer. Moreover, the expression of
miR-10b
is a potential indicator of chemosensitivity to the common 5-FU-based chemotherapy regimen.
Using multiple genetic markers, including cancer stem-like cells, we evaluated the clinical significance of circulating tumor cells (CTCs) as a prognostic factor for overall survival (OS) and ...disease-free survival (DFS) in the peripheral blood (PB) of patients with colorectal cancer (CRC) who had undergone curative surgery.
In a multi-institutional study, 735 patients with CRC were assigned to a retrospective training set (n = 420) or prospective validation set (n = 315). CTCs that expressed carcinoembryonic antigen (CEA), cytokeratin (CK) 19, CK20, and/or CD133 (CEA/CK/CD133) mRNA in PB were detected using real-time reverse transcription polymerase chain reaction assay.
In the training sets, OS and DFS of patients who were positive for CEA/CK/CD133 were significantly worse than those of patients who were negative for these markers (P < .001). At each staging analysis, OS and DFS of patients with Dukes' stage B or C cancer who were positive for CEA/CK/CD133 were significantly worse than those of patients who were negative for these markers (P < .003 and P < .001 in Dukes' stage B; P < .001 in Dukes' stage C). In contrast, in patients with Dukes' stage A, no significant differences were seen between patients who were positive for these markers and those who were negative. Cox multivariate analysis demonstrated that CEA/CK/CD133 was a significant prognostic factor for OS (hazard ratio HR, 3.84; 95% CI, 2.41 to 6.22; P < .001) and DFS (HR, 3.02; 95% CI, 1.83 to 5.00; P < .001). In particular, in patients with Dukes' stage B and C cancer, CEA/CK/CD133 demonstrated significant prognostic value. In validation sets, similar results were confirmed in patients with Dukes' stage B and C cancer.
In patients with Dukes' stage B and C CRC who require adjuvant chemotherapy, detection of CEA/CK/CD133 mRNA in PB is a useful tool for determining which patients are at high risk for recurrence and poor prognosis.
Cancer is a disease of genetic and epigenetic alterations, which are emphasized as the central mechanisms of tumor progression in the multistepwise model. Discovery of rare subpopulations of cancer ...stem cells (CSCs) has created a new focus in cancer research. The heterogeneity of tumors can be explained with the help of CSCs supported by antiapoptotic signaling. CSCs mimic normal adult stem cells by demonstrating resistance to toxic injuries and chemoradiation therapy. Moreover, they might be responsible for tumor relapse following apparent beneficial treatments. Compared with hematopoietic malignancies, conventional therapy regimes in solid tumors have improved the overall survival marginally, illustrating the profound impact of treatment resistance. This implies that the present therapies, which follow total elimination of rapidly dividing and differentiated tumor cells, need to be modified to target CSCs that repopulate the tumor. In this review article, we report on recent findings regarding the involvement of CSCs in chemoradiation resistance and provide new insights into their therapeutic implications in cancer. (Cancer Sci 2008; 99: 1871–1877)
Hepatic iron overload is a risk factor for progression of hepatocellular carcinoma (HCC), although the molecular mechanisms underlying this association have remained unclear. We now show that the ...iron-sensing ubiquitin ligase FBXL5 is a previously unrecognized oncosuppressor in liver carcinogenesis in mice. Hepatocellular iron overload elicited by FBXL5 ablation gave rise to oxidative stress, tissue damage, inflammation, and compensatory proliferation of hepatocytes and to consequent promotion of liver carcinogenesis induced by exposure to a chemical carcinogen. The tumor-promoting outcome of FBXL5 deficiency in the liver was also found to be effective in a model of virus-induced HCC. FBXL5-deficient mice thus constitute the first genetically engineered mouse model of liver carcinogenesis promoted by iron overload. In addition, dysregulation of FBXL5-mediated cellular iron homeostasis was found to be associated with poor prognosis in human HCC, suggesting that FBXL5 plays a key role in defense against hepatocarcinogenesis.
Background
Programmed cell death 1 (PD-1) inhibitors have shown significant therapeutic promise in various cancers. However, the clinical significance of PD-1 expression remains not fully understood. ...In this study, we evaluated the clinical and prognostic relevance of PD-1 expression in breast cancer (BC).
Methods
First, we analyzed
PD
-
1
mRNA expression in BC tissues and performed a survival analysis using a dataset from The Cancer Genome Atlas. Next, we measured
PD
-
1
mRNA expression in peripheral blood (PB) in BC patients by quantitative reverse-transcription polymerase chain reaction. We performed a survival analysis and evaluated the association between
PD
-
1
mRNA expression in PB and the clinicopathological features of 372 BC patients who underwent curative resection. Flow cytometry (FCM) analysis was performed to identify PD-1-expressing cells in PB. Finally, we determined whether there was a correlation of
PD
-
1
mRNA expression in PB and tumor tissue.
Results
PD
-
1
mRNA expression was significantly higher in tumor tissues compared with normal tissues. Decreased
PD
-
1
mRNA expression in tumor tissue was associated with poor overall survival (OS).
PD
-
1
mRNA expression in PB of BC patients was higher than that of healthy volunteers, and increased
PD
-
1
mRNA expression in PB was associated with poor OS. FCM revealed that PD-1 was mostly expressed on T cells in PB, predominantly in CD4
+
T cells.
PD
-
1
mRNA expression in PB was negatively correlated with
PD
-
1
mRNA expression in tumor tissue.
Conclusion
High expression of
PD
-
1
mRNA in preoperative PB could serve as an effective biomarker that indicates poor prognosis in BC.
The formation of premetastatic niches creates a fertile environment for the seeding of disseminated cancer cells in selected secondary organs. This is crucial for the development of metastasis in ...various malignancies, including breast cancer (BC). We previously reported that the loss of FBXW7 in bone marrow‐derived stromal cells promoted cancer metastasis by increasing the production of the chemokine CCL2, which attracts myeloid‐derived suppressor cells and macrophages to the premetastatic niche. Furthermore, treatment with the CCL2 inhibitor propagermanium (PG), which has been used in Japan as a therapeutic agent against chronic hepatitis B, was shown to block the enhancement of metastasis in FBXW7‐deficient mice through inhibiting the formation of premetastatic niches. Here, we describe a phase I dose‐escalation study of PG used as an antimetastatic drug for perioperative patients with primary BC. The primary end‐point was the percentage of patients who experience dose‐limiting toxicity. Twelve patients were enrolled in the study. Dose‐limiting toxicity was not observed, and the maximum dose was determined to be 90 mg/body/day. The serum concentrations of PG were nearly within the normal range in all observation days. We observed an inverse correlation between FBXW7 mRNA levels in blood and the serum concentrations of CCL2 and interleukin (IL)‐6, in agreement with our previous mouse model. Also, IL‐6 was downregulated in a PG dose‐dependent manner, as observed in mice. Thus, PG was given safely and it is expected to have antimetastatic potential in BC. This trial is registered in the UMIN Clinical Trials Registry as UMIN000022494.
A Phase I dose‐escalation study of the CCL2 inhibitor propagermanium (PG) administration was performed as an antimetastatic drug for perioperative patients with primary breast cancer (BC). This study has demonstrated a manageable safety profile and provides a basis for exploring the clinical use of PG as an antimetastatic drug for BC patients.
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