The minimum LOH region defined on chromosome 17p13.3 in human hepatocellular carcinoma with gene content analysis

Andrographolide anti-proliferation and metastasis of hepatocellular carcinoma through LncRNA MIR22HG regulation

Hepatocellular carcinoma (HCC) treatment is a major challenge. Although andrographolide (Andro) has an anti-proliferation effect on HCC, its underlying mechanism is not yet elucidated, and whether Andro can inhibit HCC metastasis has not been reported. The present study aimed to clarify whether Andro inhibits SK-Hep-1 cell proliferation and HCC metastasis, and the mechanisms. The results showed that Andro significantly reduced the survival of HCC cells and tumor weight and volume in tumor-bearing nude mice. Andro also triggered apoptosis of HCC cells and upregulated MIR22HG, Cleaved Caspase 9/7/3 expression levels, and downregulated BCL-2 mRNA, BCL-2 expression levels. Knockdown of MIR22HG or overexpression of HuR attenuated the effects of Andro on the signal transduction of mitochondrial apoptotic pathway and proliferation ability in HCC cells. Moreover, Andro significantly reduced the invasive ability of the cells and the level of HCC cell lung metastasis, upregulated miR-22-3p expression level and downregulated HMGB1 and MMP-9 expression levels. MIR22HG or miR-22-3p knockdown attenuated the effects of Andro on the signaling of HMGB1/MMP-9 pathway and invasive ability in HCC cells, while the overexpression of HMGB1 attenuated the inhibitory effects of Andro on the MMP-9 expression level and invasive ability in HCC cells. Thus, the regulation of MIR22HG-HuR/BCL-2 and MIR22HG/HMGB1 signaling pathways is involved in the anti-HCC proliferation and metastasis effects of Andro. This study provided a new pharmacological basis for Andro in HCC treatment and, for the first time, identified a natural product molecule capable of positively regulating MIR22HG, which has a robust biological function.

An Immunocompetent Environment Unravels the Proto-Oncogenic Role of miR-22

MiR-22 was first identified as a proto-oncogenic microRNA (miRNA) due to its ability to post-transcriptionally suppress the expression of the potent PTEN (Phosphatase And Tensin Homolog) tumor suppressor gene. miR-22 tumorigenic role in cancer was subsequently supported by its ability to positively trigger lipogenesis, anabolic metabolism, and epithelial-mesenchymal transition (EMT) towards the metastatic spread. However, during the following years, the picture was complicated by the identification of targets that support a tumor-suppressive role in certain tissues or cell types. Indeed, many papers have been published where in vitro cellular assays and in vivo immunodeficient or immunosuppressed xenograft models are used. However, here we show that all the studies performed in vivo, in immunocompetent transgenic and knock-out animal models, unanimously support a proto-oncogenic role for miR-22. Since miR-22 is actively secreted from and readily exchanged between normal and tumoral cells, a functional immune dimension at play could well represent the divider that allows reconciling these contradictory findings. In addition to a critical review of this vast literature, here we provide further proof of the oncogenic role of miR-22 through the analysis of its genomic locus vis a vis the genetic landscape of human cancer.

miR-22 Host Gene Enhances Nuclear Factor-kappa B Activation to Aggravate Hypoxia-induced Injury in AC16 Cardiomyocytes

Myocardial infarction (MI) is a severe life-threatening disease caused by acute and persistent ischemia and hypoxia and eventually leads to heart failure and sudden death. Long noncoding RNAs (lncRNAs) play significant roles in the pathology, diagnosis, and development of various cardiovascular diseases, including MI. This study aimed to explore the effect and molecular mechanism of lncRNA miR-22 host gene (MIR22HG) on hypoxia-induced injury in AC16 cardiomyocytes. The expression of MIR22HG and miR-24 in hypoxia-treated AC16 cardiomyocytes was detected by quantitative real-time polymerase chain reaction. Cell viability, lactate dehydrogenase release, levels of aspartate aminotransferase (AST) and creatine kinase-MB (CK-MB), and apoptosis were detected by Cell Counting Kit-8, lactate dehydrogenase (LDH) release assay, commercial enzyme-linked immune sorbent assay kits, and flow cytometry analysis, respectively. The protein levels of nuclear factor-kappa B (NF-κB) p65 and cytoplasmic inhibitor of kappa B alpha (IκBα) and phosphorylated IκBα were detected by western blot. Results showed that hypoxia treatment decreased viability and increased MIR22HG expression in AC16 cardiomyocytes. MIR22HG overexpression aggravated hypoxia-induced viability reduction, leakage of myocardial injury markers LDH, AST, and CK-MB, and apoptosis in AC16 cardiomyocytes, while MIR22HG knockdown elicited the reverse effects. MIR22HG overexpression enhanced NF-κB activation in hypoxia-treated AC16 cardiomyocytes. Inhibition of NF-κB pathway impaired the effects of MIR22HG overexpression on hypoxia-induced injury in AC16 cardiomyocytes. Moreover, MIR22HG knockdown inhibited the NF-κB pathway by upregulating miR-24 in AC16 cardiomyocytes. Inhibition of miR-24 resisted the effects of MIR22HG silencing on hypoxia-induced injury in AC16 cardiomyocytes. In conclusion, MIR22HG overexpression aggravated hypoxia-induced injury in AC16 cardiomyocytes via enhancing NF-κB activation by targeting miR-24.

Long non-coding RNA MIR22HG inhibits glioma progression by downregulating microRNA-9/CPEB3

Glioma is one of the most common and aggressive malignant intracranial tumors worldwide. Recently, non-coding RNAs have been found to play critical roles in the development of glioma. However, the exact mechanisms have not been fully elucidated. In the present study, reverse transcription-quantitative PCR was used to determine the expression level of the long non-coding RNA MIR22HG and microRNA (miR)-9, while western blot analysis was used to detect the protein expression level of CPEB3. The potential binding sites were predicted using the StarBase v2.0 online tool and the hypothesis was verified using a luciferase reporter assay. A Cell Counting Kit-8 assay was used to assess cell viability, while wound healing and Matrigel assays were used to determine the migration and invasion ability of glioma cancer cells. The results showed that MIR22HG expression level was decreased but miR-9 expression level was elevated in glioma tissues and cell lines. Furthermore, MIR22HG was found to sponge miR-9, while CPEB3 was the direct target of miR-9 in the glioma cell line. Functionally, MIR22HG regulated the proliferation, invasion and migration of the glioma cell line by targeting miR-9. CPEB3 may be involved in the progression of the glioma cell line. Taken together, these findings confirmed that MIR22HG suppressed glioma development by inhibiting the miR-9/CPEB3 axis and provides a novel therapeutic strategy for glioma treatment.

Emerging impact of the long noncoding RNA MIR22HG on proliferation and apoptosis in multiple human cancers

An increasing number of studies have shown that long noncoding RNAs (lncRNAs) play important roles in diverse cellular processes, including proliferation, apoptosis, migration, invasion, chromatin remodeling, metabolism and immune escape. Clinically, the expression of MIR22HG is increased in many human tumors (colorectal cancer, gastric cancer, hepatocellular carcinoma, lung cancer, and thyroid carcinoma), while in others (esophageal adenocarcinoma and glioblastoma), it is significantly decreased. Moreover, MIR22HG has been reported to function as a competitive endogenous RNA (ceRNA), be involved in signaling pathways, interact with proteins and interplay with miRNAs as a host gene to participate in tumorigenesis and tumor progression. In this review, we describe the biological functions of MIR22HG, reveal its underlying mechanisms for cancer regulation, and highlight the potential role of MIR22HG as a novel cancer prognostic biomarker and therapeutic target that can increase the efficacy of immunotherapy and targeted therapy for cancer treatment.

MiR-22 as a metabolic silencer and liver tumor suppressor

With obesity rate consistently increasing, a strong relationship between obesity and fatty liver disease has been discovered. More than 90% of bariatric surgery patients also have non-alcoholic fatty liver diseases (NAFLDs). NAFLD and non-alcoholic steatohepatitis (NASH), which are the hepatic manifestations of metabolic syndrome, can lead to liver carcinogenesis. Unfortunately, there is no effective medicine that can be used to treat NASH or liver cancer. Thus, it is critically important to understand the mechanism underlying the development of these diseases. Extensive evidence suggests that microRNA 22 (miR-22) can be a diagnostic marker for liver diseases as well as a treatment target. This review paper focuses on the roles of miR-22 in metabolism, steatosis, and liver carcinogenesis. Literature search is limited based on the publications included in the PubMed database in the recent 10 years.

Dysregulation of miR484-TUSC5 axis takes part in the progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. miR-484 is previously reported to be a crucial modulator during the process from precancerous lesion to cancer. Tumour suppressor candidate 5 (TUSC5) is a potential tumour suppressor, but its expression and function in HCC are obscure. In this study, we aimed to explore the roles of miR-484 and TUSC5 in HCC, and clarify the relationship between them. We demonstrated that miR-484 was significantly up-regulated in HCC, while TUSC5 was down-regulated. TUSC5 was validated as the target gene of miR-484 and both of them were associated with the prognosis of HCC patients. miR-484 mimics markedly promoted the malignant phenotypes while TUSC5 plasmid had the opposite effect. In conclusion, miR-484/TUSC5 is potential diagnostic biomarkers and therapy targets for HCC.

Identification and Functional Characterization of Long Non-coding RNA MIR22HG as a Tumor Suppressor for Hepatocellular Carcinoma

Long non-coding RNAs (lncRNAs) have recently been identified as critical regulators in tumor initiation and development. However, the function of lncRNAs in human hepatocellular carcinoma (HCC) remains largely unknown. Our study was designed to explore the biological function and clinical implication of lncRNA MIR22HG in HCC. Methods: We evaluated MIR22HG expression in 52-patient, 145-patient, TCGA, and GSE14520 HCC cohorts. The effects of MIR22HG on HCC were analyzed in terms of proliferation, invasion, and metastasis, both in vitro and in vivo. The mechanism of MIR22HG action was explored through bioinformatics, luciferase reporter, and RNA immunoprecipitation analyses. Results:MIR22HG expression was significantly down-regulated in 4 independent HCC cohorts compared to that in controls. Its low expression was associated with tumor progression and poor prognosis of patients with HCC. Forced expression of MIR22HG in HCC cells significantly suppressed proliferation, invasion, and metastasis in vitro and in vivo. Mechanistically, MIR22HG derived miR-22-3p to target high mobility group box 1 (HMGB1), thereby inactivating HMGB1 downstream pathways. Additionally, MIR22HG directly interacted with HuR and regulated its subcellular localization. MIR22HG competitively bound to human antigen R (HuR), resulting in weakened expression of HuR-stabilized oncogenes, such as β-catenin. Furthermore, miR-22-3p suppression, HuR or HMGB1 overexpression rescued the inhibitory effects caused by MIR22HG overexpression. Conclusion: Our findings revealed that MIR22HG plays a key role in tumor progression by suppressing the proliferation, invasion, and metastasis of tumor cells, suggesting its potential role as a tumor suppressor and prognostic biomarker in HCC.

LncRNA MIR22HG negatively regulates miR-141-3p to enhance DAPK1 expression and inhibits endometrial carcinoma cells proliferation

Emerging evidence has indicated that long non-coding RNAs (lncRNAs) play critical roles in tumor development and progression. Recent studies reported that lncRNA MIR22HG could play important roles in hepatocellular carcinoma and lung cancer progression. However, the expression and underlying mechanism of MIR22HG in endometrial cancer (EC) remain unclear. In the present study, qRT-PCR showed that MIR22HG expression was significantly downregulated in EC tissues. In vitro function assays showed that increased MIR22HG expression significantly inhibited EC cells proliferation, induced EC cells apoptosis, and arrested EC cells in G0/G1 phase. Furthermore, miR-141-3p was identified and confirmed to be the target of MIR22HG. Subsequently, DAPK1 was confirmed to be regulated by MIR22HG and miR-141-3p, and could play a positive role in inhibiting EC cells proliferation. Collectively, these data demonstrated that lncRNA MIR22HG could act as a tumor suppressor and inhibited EC cells proliferation through regulating miR-141-3p/DAPK1 axis, which provides a new therapeutic target for EC treatment.

Prognostic values of long non-coding RNA MIR22HG for patients with hepatocellular carcinoma after hepatectomy

Hepatocellular carcinoma (HCC) is the fifth most frequently diagnosed cancer worldwide and the second most frequent cause of cancer death. The aim of this study is to identify the association between the expression of long non-coding RNA (lncRNA) MIR22HG and the clinical and tumor characteristics of patients with HCC, and to explore the prognostic significance of lncRNA MIR22HG on patients with HCC. We retrospectively reviewed 127 patients with HCC(42 female, 85 male) who were managed in our hospital between May 1^st 2010 and June 30^th 2016. The expressions of lncRNA MIR22HG were detected by real-time PCR. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazards models. For the entire cohort of 127 patients, the normalized real-time PCR showed that the expression of lncRNA MIR22HG was lower in HCC tissues compared with corresponding nontumorous tissues. MTT assay showed that si-MIR22HG remarkably inhibited the proliferation tumor cells in three HCC cell lines including SMMC-7721, Huh-7 and Hep3B. Moreover, under-expression of MIR22HG was closely related to tumor encapsulation, microvascular invasion (MVI), and TNM stage. Cox proportional hazards analysis demonstrated that lncRNA MIR22HG under-expression was an independent risk factor associated with the prognosis of patients with HCC. In conclusion, we found that lncRNA MIR22HG expressed significantly lower in HCC tissues compared with non-tumorous tissues. Under-expression of lncRNAMIR22HG was an independent risk factor associated with the prognosis of patients with HCC.

Genomic and oncogenic preference of HBV integration in hepatocellular carcinoma

Hepatitis B virus (HBV) can integrate into the human genome, contributing to genomic instability and hepatocarcinogenesis. Here by conducting high-throughput viral integration detection and RNA sequencing, we identify 4,225 HBV integration events in tumour and adjacent non-tumour samples from 426 patients with HCC. We show that HBV is prone to integrate into rare fragile sites and functional genomic regions including CpG islands. We observe a distinct pattern in the preferential sites of HBV integration between tumour and non-tumour tissues. HBV insertional sites are significantly enriched in the proximity of telomeres in tumours. Recurrent HBV target genes are identified with few that overlap. The overall HBV integration frequency is much higher in tumour genomes of males than in females, with a significant enrichment of integration into chromosome 17. Furthermore, a cirrhosis-dependent HBV integration pattern is observed, affecting distinct targeted genes. Our data suggest that HBV integration has a high potential to drive oncogenic transformation.

Hepatitis B infection is a risk factor for hepatocellular carcinoma. Here, the authors characterise viral infection in a cohort of hepatocellular carcinoma patients and find viral integration is more frequent in males than females.

MiR-22 is frequently downregulated in medulloblastomas and inhibits cell proliferation via the novel target PAPST1

Medulloblastoma is the most frequent malignant central nervous system tumor in children. MicroRNAs (miRs) are small, non-coding RNAs that target protein-coding and non-coding RNAs, and play roles in a variety of cellular processes through regulation of multiple targets. In the present study, we analyzed miR-22 expression and its effect in cell proliferation and apoptosis in medulloblastomas. Quantitative reverse transcription PCR (RT-PCR) revealed significantly lower expression of miR-22 in 19 out of 27 (70%) medulloblastomas, D341, DAOY, ONS-76 medulloblastoma cell lines, compared with normal cerebellum. Forced expression of miR-22 by lentiviral vector transfection reduced cell proliferation and induced apoptosis, while knockdown of miR-22 increased proliferative activity in DAOY and ONS-76 cells. DAOY cells with miR-22 overexpression in nude mice yielded tumors smaller than those originated from control DAOY cells. Microarray analysis in DAOY cells with forced miR-22 expression showed significant changes in expression profiles, PAPST1 being the most significantly (10 folds) downregulated gene. Quantitative RT-PCR revealed PAPST1 mRNA upregulation in 18 out of 27 (67%) medulloblastomas. In addition, a luciferase reporter assay in ONS-76 and DAOY cells suggested that miR-22 directly targets the PAPST1 gene, and lentivirus-mediated knockdown of PAPST1 suppressed proliferation of DAOY and ONS-76 medulloblastoma cells. These results suggest that frequently downregulated miR-22 expression is associated with cell proliferation in medulloblastomas, and this may be at least in part via PAPST1, which is a novel target of miR-22.

Loss of heterozygosity and methylation of multiple tumor suppressor genes on chromosome 3 in hepatocellular carcinoma

BACKGROUND

Genetic and epigenetic alterations are the two key mechanisms in the development of hepatocellular carcinoma (HCC). However, how they contribute to hepatocarcinogenesis and the correlation between them has not been fully elucidated.

METHODS

A total of 48 paired HCCs and noncancerous tissues were used to detect loss of heterozygosity (LOH) and the methylation profiles of five tumor suppressor genes (RASSF1A, BLU, FHIT, CRBP1, and HLTF) on chromosome 3 by using polymerase chain reaction (PCR) and methylation-specific PCR. Gene expression was analyzed by immunohistochemistry and reverse transcription (RT)-PCR.

RESULTS

Sixteen of 48 (33.3 %) HCCs had LOH on at least one locus on chromosome 3, and two smallest common deleted regions (3p22.3-24.3 and 3p12.3-14.2) were identified. RASSF1A, BLU, and FHIT showed very high frequencies of methylation in HCCs (100, 81.3, and 64.6 %, respectively) and noncancerous tissues, but not in liver tissues from control patients. Well-differentiated HCCs showed high methylation frequencies of these genes but very low frequencies of LOH. Furthermore, BLU methylation was associated with an increased level of alpha-fetoprotein, and FHIT methylation was inversely correlated with HCC recurrence. In comparison, CRBP1 showed moderate frequencies of methylation, while HLTF showed low frequencies of methylation, and CRBP1 methylation occurred mainly in elderly patients. Treatment with 5-aza-2'-deoxycytidine demethylated at least one of these genes and restored their expression in a DNA methylation-dependent or -independent manner.

CONCLUSIONS

Hypermethylation of RASSF1A, BLU, and FHIT is a common and very early event in hepatocarcinogenesis; CRBP1 methylation may also be involved in the later stage. Although LOH was not too frequent on chromosome 3, it may play a role as another mechanism in hepatocarcinogenesis.

Phosphoinositide phosphatases: just as important as the kinases

Phosphoinositide phosphatases comprise several large enzyme families with over 35 mammalian enzymes identified to date that degrade many phosphoinositide signals. Growth factor or insulin stimulation activates the phosphoinositide 3-kinase that phosphorylates phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P(2)] to form phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P(3)], which is rapidly dephosphorylated either by PTEN (phosphatase and tensin homologue deleted on chromosome 10) to PtdIns(4,5)P(2), or by the 5-phosphatases (inositol polyphosphate 5-phosphatases), generating PtdIns(3,4)P(2). 5-phosphatases also hydrolyze PtdIns(4,5)P(2) forming PtdIns(4)P. Ten mammalian 5-phosphatases have been identified, which regulate hematopoietic cell proliferation, synaptic vesicle recycling, insulin signaling, and embryonic development. Two 5-phosphatase genes, OCRL and INPP5E are mutated in Lowe and Joubert syndrome respectively. SHIP [SH2 (Src homology 2)-domain inositol phosphatase] 2, and SKIP (skeletal muscle- and kidney-enriched inositol phosphatase) negatively regulate insulin signaling and glucose homeostasis. SHIP2 polymorphisms are associated with a predisposition to insulin resistance. SHIP1 controls hematopoietic cell proliferation and is mutated in some leukemias. The inositol polyphosphate 4-phosphatases, INPP4A and INPP4B degrade PtdIns(3,4)P(2) to PtdIns(3)P and regulate neuroexcitatory cell death, or act as a tumor suppressor in breast cancer respectively. The Sac phosphatases degrade multiple phosphoinositides, such as PtdIns(3)P, PtdIns(4)P, PtdIns(5)P and PtdIns(3,5)P(2) to form PtdIns. Mutation in the Sac phosphatase gene, FIG4, leads to a degenerative neuropathy. Therefore the phosphatases, like the lipid kinases, play major roles in regulating cellular functions and their mutation or altered expression leads to many human diseases.

The human LIS1 is downregulated in hepatocellular carcinoma and plays a tumor suppressor function

The human lissencephaly-1 gene (LIS1) is a disease gene responsible for Miller-Dieker lissencephaly syndrome (MDL). LIS1 gene is located in the region of chromosome 17p13.3 that is frequency deleted in MDL patients and in human liver cancer cells. However, the expression and significance of LIS1 in liver cancer remain unknown. Here, we investigated the expression of LIS1 in hepatocellular carcinoma (HCC) tissues by real-time PCR, Western blot, and immunohistochemistry. The results indicated that the mRNA and protein levels of LIS1 were downregulated in about 70% of HCC tissues, and this downregulation was significantly associated with tumor progression. Functional studies showed that the reduction of LIS1 expression in the normal human liver cell line QSG7701 or the mouse fibroblast cell line NIH3T3 by shRNA resulted in colony formation in soft agar and xenograft tumor formation in nude mice, demonstrating that a decrease in the LIS1 level can promote the oncogenic transformation of cells. We also observed that the phenotypes of LIS1-knockdown cells displayed various defective mitotic structures, suggesting that the mechanism by which reduced LIS1 levels results in tumorigenesis is associated with its role in mitosis. Furthermore, we demonstrated that ectopic expression of LIS1 could significantly inhibit HCC cell proliferation and colony formation. Our results suggest that LIS1 plays a potential tumor suppressor role in the development and progression of HCC.

A link between mir-100 and FRAP1/mTOR in clear cell ovarian cancer

MicroRNAs (miRNAs) are small noncoding RNAs that direct gene regulation through translational repression and degradation of complementary mRNA. Although miRNAs have been implicated as oncogenes and tumor suppressors in a variety of human cancers, functional roles for individual miRNAs have not been described in clear cell ovarian carcinoma, an aggressive and chemoresistant subtype of ovarian cancer. We performed deep sequencing to comprehensively profile miRNA expression in 10 human clear cell ovarian cancer cell lines compared with normal ovarian surface epithelial cultures and discovered 54 miRNAs that were aberrantly expressed. Because of the critical roles of the phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog 1/mammalian target of rapamycin (mTOR) pathway in clear cell ovarian cancer, we focused on mir-100, a putative tumor suppressor that was the most down-regulated miRNA in our cancer cell lines, and its up-regulated target, FRAP1/mTOR. Overexpression of mir-100 inhibited mTOR signaling and enhanced sensitivity to the rapamycin analog RAD001 (everolimus), confirming the key relationship between mir-100 and the mTOR pathway. Furthermore, overexpression of the putative tumor suppressor mir-22 repressed the EVI1 oncogene, which is known to suppress apoptosis by stimulating phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog 1 signaling. In addition to these specific effects, reversing the expression of mir-22 and the putative oncogene mir-182 had widespread effects on target and nontarget gene populations that ultimately caused a global shift in the cancer gene signature toward a more normal state. Our experiments have revealed strong candidate miRNAs and their target genes that may contribute to the pathogenesis of clear cell ovarian cancer, thereby highlighting alternative therapeutic strategies for the treatment of this deadly cancer.

The role of the inositol polyphosphate 5-phosphatases in cellular function and human disease

Phosphoinositides are membrane-bound signalling molecules that regulate cell proliferation and survival, cytoskeletal reorganization and vesicular trafficking by recruiting effector proteins to cellular membranes. Growth factor or insulin stimulation induces a canonical cascade resulting in the transient phosphorylation of PtdIns(4,5)P(2) by PI3K (phosphoinositide 3-kinase) to form PtdIns(3,4,5)P(3), which is rapidly dephosphorylated either by PTEN (phosphatase and tensin homologue deleted on chromosome 10) back to PtdIns(4,5)P(2), or by the 5-ptases (inositol polyphosphate 5-phosphatases), generating PtdIns(3,4)P(2). The 5-ptases also hydrolyse PtdIns(4,5)P(2), forming PtdIns4P. Ten mammalian 5-ptases have been identified, which share a catalytic mechanism similar to that of the apurinic/apyrimidinic endonucleases. Gene-targeted deletion of 5-ptases in mice has revealed that these enzymes regulate haemopoietic cell proliferation, synaptic vesicle recycling, insulin signalling, endocytosis, vesicular trafficking and actin polymerization. Several studies have revealed that the molecular basis of Lowe's syndrome is due to mutations in the 5-ptase OCRL (oculocerebrorenal syndrome of Lowe). Futhermore, the 5-ptases SHIP [SH2 (Src homology 2)-domain-containing inositol phosphatase] 2, SKIP (skeletal muscle- and kidney-enriched inositol phosphatase) and 72-5ptase (72 kDa 5-ptase)/Type IV/Inpp5e (inositol polyphosphate 5-phosphatase E) are implicated in negatively regulating insulin signalling and glucose homoeostasis in specific tissues. SHIP2 polymorphisms are associated with a predisposition to insulin resistance. Gene profiling studies have identified changes in the expression of various 5-ptases in specific cancers. In addition, 5-ptases such as SHIP1, SHIP2 and 72-5ptase/Type IV/Inpp5e regulate macrophage phagocytosis, and SHIP1 also controls haemopoietic cell proliferation. Therefore the 5-ptases are a significant family of signal-modulating enzymes that govern a plethora of cellular functions by regulating the levels of specific phosphoinositides. Emerging studies have implicated their loss or gain of function in human disease.

Acute lymphoblastic leukemia in a patient with Miller-Dieker syndrome

A 15-month-old girl with Miller-Dieker syndrome, a contiguous gene deletion syndrome involving chromosome 17p13.3 and resulting in lissencephaly, was diagnosed with precursor B-cell acute lymphoblastic leukemia. Cytogenetic analysis identified both the previously detected 17p13.3 deletion and additional complex numerical and structural abnormalities, including loss of chromosome 9, isochromosome 9q and interstitial deletion of 20q. This is, to our knowledge, the first report of acute leukemia in the setting of Miller-Dieker syndrome. Herein we review the literature regarding Miller-Dieker syndrome, with particular attention to the presence of several candidate tumor suppressor genes within the deleted material.

HCCS1 overexpression induces apoptosis via cathepsin D and intracellular calcium, and HCCS1 disruption in mice causes placental abnormality

Hepatocellular carcinoma suppressor 1 (HCCS1) was discovered as a novel tumor suppressor gene. We recently observed that adenovirus-mediated gene transfer of HCCS1 leads to cytotoxicity to human hepatocarcinoma cells. Here, we have demonstrated that adenovirus-mediated overexpression of HCCS1 induces apoptosis in hepatocarcinoma cells and have further characterized the apoptotic cascade. The results showed that lysosomal cathepsin D is released into the cytosol in response to HCCS1 overexpression and consequently triggers Bax insertion into the mitochondrial membrane, which leads to the release of cytochrome c. In addition, HCCS1 overexpression can induce an increase in intracellular free Ca(2+) concentration, which also results in cytochrome c release. The released cytochrome c activates downstream caspases, leading to the occurrence of the late stages of apoptosis. Moreover, we demonstrated that the disruption of HCCS1 in mice leads to embryonic lethality, accompanied by abnormal labyrinth architecture resulting from the excessive proliferation of trophoblast cells in the placenta. These results suggest that HCCS1 plays a role in apoptosis regulation and development.

Recurrent chromosome 10 aberrations and Tp53 mutations in rat endometrial adenocarcinomas

Human genetic heterogeneity and differences in the environment and life style make analysis of complex diseases such as cancer difficult. By using inbred animal strains, the genetic variability can be minimized and the environmental factors can be reasonably controlled. Endometrial adenocarcinoma (EAC) is the most common gynecologic malignancy, ranking fourth in incidence among tumors in women. The inbred BDII rat strain is genetically prone to spontaneously develop hormone-related EAC, and can be used as a tool to investigate and characterize genetic changes in this tumor type. In the present project, BDII females were crossed to males from two nonsusceptible rat strains and F1, F2, and backcross progeny were produced. Genetic and molecular genetic analysis of tumors showed that rat chromosome 10 (RNO10) was frequently involved in genetic changes. Our data indicate that often there was loss of chromosomal material in the proximal to middle part of the chromosome followed by gains in distal RNO10. This suggested that there is a tumor suppressor gene(s) in the proximal to middle part of RNO10 and an oncogene(s) in the distal part of the chromosome with potential significance in EAC development. The Tp53 gene, located at band RNO10q24-q25, was a strong candidate target for the observed aberrations affecting the middle part of the chromosome. However, our Tp53 gene mutation analyses suggested that a second gene situated very close to Tp53 might be the main target for the observed pattern of genetic changes.

ARS2 is a conserved eukaryotic gene essential for early mammalian development

Determining the functions of novel genes implicated in cell survival is directly relevant to our understanding of mammalian development and carcinogenesis. ARS2 is an evolutionarily conserved gene that confers arsenite resistance on arsenite-sensitive Chinese hamster ovary cells. Little is known regarding the function of ARS2 in mammals. We report that ARS2 is transcribed throughout embryonic development and is expressed ubiquitously in mouse and human tissues. The mouse ARS2 protein is predominantly localized to the nucleus, and this nuclear localization is ablated in ARS2-null embryos, which in turn die around the time of implantation. After 24 h of culture, ARS2-null blastocysts contained a significantly greater number of apoptotic cells than wild-type or heterozygous blastocysts. By 48 h of in vitro culture, null blastocysts invariably collapsed and failed to proliferate. These data indicate ARS2 is essential for early mammalian development and is likely involved in an essential cellular process. The analysis of data from several independent protein-protein interaction studies in mammals, combined with functional studies of its Arabidopsis ortholog, SERRATE, suggests that this essential process is related to RNA metabolism.

Nucleoredoxin, a novel thioredoxin family member involved in cell growth and differentiation

Thioredoxin (TRX) family proteins are involved in various biologic processes by regulating the response to oxidative stress. Nucleoredoxin (NRX), a relatively uncharacterized member of the TRX family protein, has recently been reported to regulate the Wnt/beta-catenin pathway, which itself regulates cell fate and early development, in a redox-dependent manner. In this review, we describe the TRX family proteins and discuss in detail the similarities and differences between NRX and other TRX family proteins. Although NRX possesses a conserved TRX domain and a catalytic motif for oxidoreductase activity, its sequence homology to TRX is not as high as that of the close relatives of TRX. The sequence of NRX is more similar to that of tryparedoxin (TryX), a TRX family member originally identified in parasite trypanosomes. We also discuss the reported properties and potential physiologic roles of NRX.

Analysis of chromosome 10 aberrations in rat endometrial cancer-evidence for a tumor suppressor locus distal to Tp53

We have recently shown in the BDII rat model of human endometrial adenocarcinoma (EAC), rat chromosome 10 (RNO10) is frequently involved in chromosomal aberrations. In the present study, we investigated the association between RNO10 deletions, allelic imbalance (AI) at RNO10q24 and Tp53 mutation in 27 rat EAC tumors. We detected chromosomal breakage accompanied by loss of proximal and/or gain of distal parts of RNO10 in approximately 2/3 of the tumors. This finding is suggestive of a tumor suppressor activity encoded from the proximal RNO10. Given the fact that Tp53 is located at RNO10q24-q25, we then performed Tp53 mutation analysis. However, we could not find a strong correlation between AI/deletions at RNO10q24 and Tp53 mutation. Instead, the observed patterns for AI, chromosomal breaks and deletions suggest that major selection was directed against a region located close to, but distal of Tp53. In different human malignancies a similar situation of AI at chromosome band 17p13.3 (HSA17p13.3) unassociated with TP53 mutation has been observed. Although RNO10 is largely homologous to HSA17, the conservation with respect to gene order among them is not extensive. We utilized publicly available draft DNA sequences to study intrachromosomal rearrangement during the divergence between HSA17 and RNO10. By using reciprocal comparison of rat and human genome data, we could substantially narrow down the candidate tumor suppressor region in rat from 3 Mb to a chromosomal segment of about 0.5 Mb in size. These results provide scientific groundwork for identification of the putative tumor suppressor gene(s) at 17p13.3 in human tumors.

Inhibition of Aurora-B function increases formation of multinucleated cells in p53 gene deficient cells and enhances anti-tumor effect of temozolomide in human glioma cells

Cell division is an elemental process, and mainly consists of chromosome segregation and subsequent cytokinesis. Some errors in this process have the possibility of leading to carcinogenesis. Aurora-B is known as a chromosomal passenger protein that regulates cell division. In our previous studies of giant cell glioblastoma, we reported that multinucleated giant cells resulted from aberrations in cytokinesis with intact nuclear division occurring in the early mitotic phase, probably due to Aurora-B dysfunction. In this study, as we determined p53 gene mutation occurring in multinucleated giant cell glioblastoma, we investigated the role of Aurora-B in formation of multinucleated cells in human neoplasm cells with various p53 statuses as well as cytotoxity of glioma cells to temozolomide (TMZ), a common oral alkylating agent used in the treatment of gliomas. The inhibition of Aurora-B function by small-interfering (si)RNA led to an increase in the number of multinucleated cells and the ratios of G2/M phase in p53-mutant and p53-null cells, but not in p53-wild cells or the cells transduced adenovirally with wild-p53. The combination of TMZ and Aurora-B-siRNA remarkably inhibited the cell viability of TMZ-resistant glioma cells. Accordingly, our results suggested that Aurora-B dysfunction increases in the appearance of multinucleated cells in p53 gene deficient cells, and TMZ treatment in combination with the inhibition of Aurora-B function may become a potential therapy against p53 gene deficient and chemotherapeutic-resistant human gliomas.

MicroRNAs and chromosomal abnormalities in cancer cells

Over the past five decades, a plethora of nonrandom chromosomal abnormalities have been consistently reported in malignant cells facilitating the identification of cancer-associated protein coding oncogenes and tumor suppressors. The genetic dissection of hot spots for chromosomal abnormalities in the age of the sequenced human genome resulted in the discovery that microRNA (miRNA) genes, encoding for a class of small noncoding RNAs, frequently resides in such genomic regions. The combination of nonrandom chromosomal abnormalities and other types of genetic alterations or epigenetic events contribute to downregulation or overexpression of miRNAs. The consequent abnormal expression of miRNAs affect cell cycle, survival and differentiation programs and selective targeting of these noncoding genes could provide novel therapeutic options for killing the malignant cells.

Human genome research in China

Significant progress in human genome research has been made in China since 1994. This review aims to give a brief and incomplete introduction to the major research institutions and their achievements in human genome sequencing and functional genomics in medicine, with emphasis on the "1% Sequencing Project", the generation of single nucleotide polymorphism and haplotype maps of the human genome, disease gene identification, and the molecular characterization of leukemia and other diseases. Chinese efforts towards the sequencing of pathogenic microbial genomes and of the rice (Oryza sativa ssp. Indica) genome are also described.

Human microRNA genes are frequently located at fragile sites and genomic regions involved in cancers

A large number of tiny noncoding RNAs have been cloned and named microRNAs (miRs). Recently, we have reported that miR-15a and miR-16a, located at 13q14, are frequently deleted and/or down-regulated in patients with B cell chronic lymphocytic leukemia, a disorder characterized by increased survival. To further investigate the possible involvement of miRs in human cancers on a genome-wide basis, we have mapped 186 miRs and compared their location to the location of previous reported nonrandom genetic alterations. Here, we show that miR genes are frequently located at fragile sites, as well as in minimal regions of loss of heterozygosity, minimal regions of amplification (minimal amplicons), or common breakpoint regions. Overall, 98 of 186 (52.5%) of miR genes are in cancer-associated genomic regions or in fragile sites. Moreover, by Northern blotting, we have shown that several miRs located in deleted regions have low levels of expression in cancer samples. These data provide a catalog of miR genes that may have roles in cancer and argue that the full complement of miRs in a genome may be extensively involved in cancers.

Two variants of the human hepatocellular carcinoma-associated HCAP1 gene and their effect on the growth of the human liver cancer cell line Hep3B

We have cloned a cDNA from chromosome band 17p13.3, designated as HCAP1 (HCC-associated protein 1, originally named HC56). Database searches revealed that HCAP1 shares most of its open reading frame with GEMIN4. Single nucleotide polymorphism (SNP) screening revealed a high incidence of SNP in the coding region of HCAP1 (12 SNP sites). A collection of 140 controls and 22 cases from the Qidong area was genotyped at 6 SNP sites. The 22 cases exhibited higher frequencies of minor alleles than did the controls, and 2 sites revealed significant differences between the controls and the cases. We constructed 2 haplotypes, HCAP1-N (with common alleles at 5 SNP sites) and HCAP1-M (with minor alleles at 5 SNP sites), in a mammalian expression system. Both haplotypes resulted in a remarkable reduction in colony formation and suppression of cell growth after being transfected into the human hepatocellular carcinoma (HCC) cell line. The inhibitory effect of HCAP1-N was stronger than that of HCAP1-M. Different haplotypes also resulted in different gene expression profiles in the Hep3B cell line according to an examination of 588 genes on an Atlas membrane. The expression induced by HCAP1-M caused an up-regulation of genes involved in cellular proliferation and a down-regulation of genes involved in cellular apoptosis and DNA repair. These results, in addition to the statistical data, are biological evidence that the HCAP1-M variant of HCAP1 has a reduced inhibitory effect on hepatocarcinoma cell growth and an impaired DNA repair system. This suggests that HCAP1-M may be related to cancer susceptibility.

A decade's studies on metastasis of hepatocellular carcinoma

Metastasis remains one of the major challenges before hepatocellular carcinoma (HCC) is finally conquered. This paper summarized a decade's studies on HCC metastasis at the Liver Cancer Institute of Fudan University. We have established a stepwise metastatic human HCC model system, which included a metastatic HCC model in nude mice (LCI-D20), a HCC cell line with high metastatic potential (MHCC97), a relatively low metastatic potential cell clone (MHCC97L) and several stepwise high metastatic potential cell clones (MHCC97H, HCCLM3, and HCCLM6) from their parent MHCC97 cell. Endeavors have been made for searching human HCC metastasis-related chromosomes/proteins/genes. Monogene-based studies revealed that HCC invasion/metastasis was similar to that of other solid tumors, and the biological characteristics of small HCC were only slightly better than that of large HCC. Using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), genotyping, cDNA microarray, and 2-dimensional gel electrophoresis, we obtained some interesting results. In particular, in collaboration with the National Institute of Health (NIH) in the United States, we generated a molecular signature that can classify metastatic HCC patients, identified osteopontin as a lead gene in the signature, and found that genes favoring metastasis progression were initiated in the primary tumors. We also found that chromosome 8p deletion, particularly in the region of 8p23, was associated with HCC metastasis. Cytokeratin 19 was identified as one of the proteins, which was found in MHCC97H, but not in MHCC97L cells. Experimental interventions using the high metastatic nude mice model have provided clues for the prevention of HCC metastasis. Translation from workbench to bedside demonstrated that serum VEGF, microvessel density, and p53 scoring may be of value for the prediction of postoperative metastatic recurrence. Interferon alpha proved effective for the prevention of recurrence both experimentally and clinically. In conclusion, HCC metastasis that probably initiated in the primary tumor is a multigene-involved, multistep, and changing process. The further elucidation of the mechanism underlying HCC metastasis will provide a more solid basis for the prediction and prevention of the metastatic recurrence of HCC.