It was recently discovered that a subset of osteoblasts functions as a key component of the hematopoietic stem cells (HSC) niche in vivo, controlling HSC self-renewal and multi-lineage differentiation. Disruption of Smad4 gene specifically in osteoblasts leads to a remarkable decrease of osteoblast number and endosteal surface area. In order to elucidate if the osteoblast loss has any effect on hematopoietic activity, the bone marrow (BM) and extramedullary hematopoiesis in the osteoblast-specific Smad4 knockout mice were systematically analyzed, the proportions of mature hematocytes in BM, liver and spleen were detected by flow cytometry, the hematopoietic progenitor number in different stages was measured by colong-forming assay, CFU-S and analysis of LSK cells. The results indicated that the conditional mutant mice demonstrated normal BM hematopoiesis without sign of extramedullary hematopoiesis. Furthermore, the proportion of hematopoietic progenitor cells was normal, while cell number/body weight of the conditional knockout mice increased. It is concluded that hematopoiesis is normally maintained in osteoblast-specific Smad4 knockout mice, and osteoblast loss does not of necessity result in the decrease in BM hematopoiesis.
Animals ; Bone Marrow Cells ; cytology ; Hematopoiesis ; Hematopoietic Stem Cells ; cytology ; physiology ; Mice ; Mice, Knockout ; Osteoblasts ; cytology ; physiology ; Smad4 Protein ; genetics

Familial juvenile polyposis (FJP) is a rare autosomal dominant hereditary disorder that is characterized by the development of multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of cancer. Recently, germline mutations, including mutations in the SMAD4, BMPR1A, PTEN and, possibly, ENG genes, have been found in patients with juvenile polyps. We herein report a family with juvenile polyposis syndrome (JPS) with a novel germline mutation in the SMAD4 gene. A 21-year-old man presented with rectal bleeding and was found to have multiple polyps in his stomach, small bowel, and colon. His mother had a history of gastrectomy for multiple gastric polyps with anemia and a history of colectomy for colon cancer. A review of the histology of the polyps revealed juvenile polyps in both patients. Subsequently, mutation screening in DNA samples from the patients revealed a germline mutation in the SMAD4 gene. The pair had a novel mutation in exon 10 (stop codon at tyrosine 413). To our knowledge, this mutation has not been previously described. Careful family history collection and genetic screening in JPS patients are needed to identify FJP, and regular surveillance is recommended.
Exons ; Female ; Gastrointestinal Neoplasms/*genetics/pathology ; Germ-Line Mutation ; Humans ; Intestinal Polyposis/*congenital/genetics/pathology ; Male ; Middle Aged ; Neoplastic Syndromes, Hereditary/*genetics/pathology ; Smad4 Protein/*genetics ; Young Adult

Loss of transforming growth factor (TGF)-beta signaling has been implicated in malignant transformation of various tissues. Smad4 plays a central role in the signal transduction of TGF-beta. Deletion or mutation of Smad4 has been described in a number of cancers. This study was aimed to investigate a potential role of Smad4 in leukemia including its expression and location in blast cells. The mononuclear cells were separated from bone marrow of leukemia patients. The samples, blast cells of which were more than 90% in mononuclear cells, were selected. The expression and location of Smad4 protein were analyzed by immunohistochemistry methods. The results showed that the Smad4 protein located mainly in nucleus, part of this protein located in cytoplasma, the expressions of Smad4 were not detected in 6 out of 9 ALL patients, in 7 out of 24 AML patients and in 1 out of 2 CML patients; these leukemia patients, in whose cells the expression of Smad4 was not detected, included one L1 and one L3, four L2, one M0, one M1, two M2a, one M3a, one M4b, one M6 and one CML. In conclusion, the Smad4 protein was mainly in nucleus, the deletion or functional change of Smad4 may related with the pathogenesis of human AML.
Humans ; Leukemia, Myeloid, Acute ; genetics ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; Signal Transduction ; Smad4 Protein ; biosynthesis ; genetics ; Transforming Growth Factor beta ; biosynthesis ; genetics

OBJECTIVEto explore whether 6 tagging single nucleotide polymorphisms (SNPs) within SMAD4 gene were involved in the genetic susceptibility of coal worker's pneumoconiosis (CWP) by case-control study.

METHODSthis study consisted of 438 CWP patients and 448 controls. All study subjects were Han Chinese, underground coal miners and recruited from coal mines of Xuzhou Mining Business Group Co Ltd. The 5 ml venous blood sample was obtained from all studied subjects and extracted genome DNA from the isolated leucocytes. Six SNPs were selected from the HapMap and detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTSthe single SNP analyses showed that the genotype frequencies of SMAD4 (rs10502913) was significantly different from those in controls (P < 0.05). Multivariate logistic regression analyses revealed that SMAD4 (rs10502913) AA genotype was associated with increased risk of CWP (adjusted OR = 1.63, 95%CI = 1.00 - 2.69, P = 0.05) and this was evident among subgroups of those smoker (adjusted OR = 2.28, 95%CI = 1.09 ∼ 4.80, P < 0.05) and cases with stage I (adjusted OR = 2.42, 95%CI = 1.41 ∼ 4.14, P < 0.01). The SMAD4 (rs9304407) GG genotype was associated with an decreased risk of CWP (adjusted OR = 0.65, 95%CI = 0.43 ∼ 0.98, P < 0.05) and the further stratification analysis showed that the risk of CWP was decreased in nonsmoking groups.

CONCLUSIONSour results suggest that individuals with the SMAD4 (rs10502913) AA genotype was associated with an increased risk of CWP. However, carriers of SMAD4 (rs9304407) GG genotype have a protective effect on the developing CWP.

Aged ; Anthracosis ; genetics ; Case-Control Studies ; Coal Mining ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Smad4 Protein ; genetics

OBJECTIVETo investigate the effects of the plasma containing Qianlongtong Capsule (QLT)-containing plasma on the expression of the Smad4 gene in prostate stromal cells in vitro and provide some experimental evidence for the treatment of benign prostatic hyperplasia (BPH) with Chinese medicinal compound.

METHODSFifteen cases of BPH were equally randomized to three groups to be treated with QLT at a high dose (6 capsules once), a medium dose (3 capsules once), and a low dose (1.5 capsules once), tid, for 7 days consecutively. QLT-containing plasma was collected from the patients. Prostate stromal cells were identified by immunofluorescence when they became monolayered and cultured in the QLT-containing plasma for 24 hours, followed by detection of the expression of the Smad4 gene by real-time quantitative PCR and that of the Smad4 protein by Western blot.

RESULTSAfter treatment with the QLT-containing plasma, the expression of the Smad4 gene in the stromal cells was significantly increased in a dose-dependent manner as compared with the blank control and no-QLT groups (P < 0.01). The expression of the Smad4 protein was also markedly elevated after treatment. The differences were statistically significant between the blank control and medium-dose groups (P < 0.01), low-dose and medium-dose groups (P < 0.05), and high-dose and the other groups (P < 0.01), but not between the blank control and low-dose groups (P > 0.05).

CONCLUSIONQLT-containing plasma could inhibit the proliferation and improve the apoptotic index of prostate stromal cells in vitro, which was related to the elevation of the mRNA and protein expressions of Smad4.

Apoptosis ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Male ; Prostate ; drug effects ; metabolism ; RNA, Messenger ; genetics ; Smad4 Protein ; genetics ; metabolism ; Stromal Cells ; drug effects ; metabolism

OBJECTIVETo observe the expression of Smad4, the core of TGF-beta/Smads signal transduction pathway in different prostate cancer cell lines, and explore their molecular mechanism of bone metastatic potential.

METHODSThe Millicell polycarbonate filter coated with matrigel was used to confirm the invasive potency of LNCaP and ARCaP cell lines (IF11 and IA8). The expressions of the Smad4 protein and mRNA in these prostate cancer cells with different metastatic potentials were detected by Western blotting and RT-PCR, respectively.

RESULTSARCaP cell lines (IF11 and IA8) exhibited a stronger potency of invasion than LNCaP (P < 0.01). The Smad4 protein and mRNA highly expressed in the LNCaP cell line that was well-known with a low metastatic potential, but not in the ARCaP (IF11 or IA8) cells with high metastatic potentials (P < 0.01).

CONCLUSIONSmad4 expresses differently in LNCaP and ARCaP cell lines with different metastatic potentials and, as a tumor suppressive gene, its deficient expression may play an important role in the invasion and metastasis of advanced prostate cancer.

Cell Line, Tumor ; Humans ; Male ; Neoplasm Metastasis ; Prostatic Neoplasms ; metabolism ; pathology ; RNA, Messenger ; genetics ; Smad4 Protein ; biosynthesis ; Transforming Growth Factor beta ; metabolism

OBJECTIVETo investigate the effect of dihydrotestosterone (DHT) on the gene transcriptions and expressions of Smad3 and Smad4 in androgen dependent prostate cancer cell line LNCaP, and whether this effect can be suppressed by the androgen receptor inhibitor flutamide.

METHODSThe androgen dependent prostate cancer cell line LNCaP was cultured in RPMI 1640 medium and treated with different concentrations of DHT(2, 10, 50 nmol/L) and flutamide (100 nmol/L). Quantitative reverse transcription PCR (RT-PCR) was used to detect the mRNAs of Smad3 and Smad4. The expressions of Smad3 and Smad4 protein were detected by Western blot assay.

RESULTSCompared with the control group without any DHT or flutamide, higher concentration(10, 50 nmol/L) of DHT enhanced the transcription of Smad3 mRNA (P <0.05). Serial concentrations of DHT increased the expression of Smad3 protein(P < 0.05). Flutamide inhibited the up-regulation of both Smad3 mRNA transcription and expression significantly (P <0.05). 10 nmol/L DHT significantly suppressed the transcription of Smad4 (P <0.05). There was considerable suppressions of Smad4 expression at the presence of DHT in different concentrations (P < 0.05). And the degree of this suppression was more significant than that of DHT on Smad4 mRNA transcription. Flutamide inhibited the suppressive effects of DHT on both Smad4 mRNA transcription and expression.

CONCLUSIONDHT can enhance the transcription and expression of Smad3, while it decreases the transcription and expression of Smad4 in LNCaP cell line. There is a possible crosstalk between the AR signal and TGF-beta signal passways at the level of Smads.

Androgens ; physiology ; Cell Line, Tumor ; Dihydrotestosterone ; pharmacology ; Flutamide ; pharmacology ; Humans ; Male ; Neoplasms, Hormone-Dependent ; metabolism ; Prostatic Neoplasms ; metabolism ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Smad3 Protein ; biosynthesis ; genetics ; Smad4 Protein ; biosynthesis ; genetics ; Transcription, Genetic

OBJECTIVETo analyze clinical features of 4 families with hereditary hemorrhagic telangiectasia (HHT) and potential mutations of ENG, ACVRL1 and SMAD4 genes.

METHODSFour unrelated HHT patients and their affected family members were analyzed. All exons and flanking regions of ENG, ACVRL1 and SMAD4 genes were analyzed with PCR and direct sequencing and multiplex ligation-dependent probe amplification (MLPA) methods.

RESULTSEleven patients from the 4 families were enrolled in this study. Two ENG and 1 ACVRL1 mutations were identified, among which an ENG mutation (c.207G>A; p.L69L) and an ACVRL1 mutation (c.817C>T; p.L273L) have been previously reported. In addition, a novel ENG mutation (c.1004A>T; p.Q335L) has been found in 3 different families. Similar mutations were not detected in 200 healthy individuals. No mutations of ENG, ACVRL1 and SMAD4 were found in the fourth family.

CONCLUSIONA novel mutation c.1004A>T (p. Q335L) of ENG has been identified in patients with HHT. And there is significant phenotypic variability and genetic heterogeneity with the disease.

Activin Receptors, Type II ; genetics ; Adolescent ; Adult ; Amino Acid Sequence ; Antigens, CD ; genetics ; Endoglin ; Female ; Genetic Testing ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Receptors, Cell Surface ; genetics ; Smad4 Protein ; genetics ; Telangiectasia, Hereditary Hemorrhagic ; diagnosis ; genetics

OBJECTIVETo investigate the changes in transforming growth factor beta 1 (TGF-beta1)/Smads signaling pathway in rats with chemical hepatocarcinogenesis.

METHODSFresh diethylnitrosamine (DENA) solution was administered in SD rats to induce hepatocellular carcinoma (HCC). The protein expressions of TGF-beta1, phosphorylated Smad2, Smad4 and Smad7 were detected in these rats with immunohistochemistry, and the mRNA expression of Smad4 was evaluated with RT-PCR.

RESULTSCirrhotic nodules occurred in the rats 8 weeks after DENA treatment, and HCC nodules were found 16 weeks after the treatment. In the normal liver tissue, very low levels of TGF-beta1 and Smad4 expressions, low Smad7 expression and high phosphorylated Smad2 expression were detected. The development of liver cirrhosis was accompanied by increased expressions of TGF-beta1, Smad4 and Smad7 but at 8 weeks after DENA treatment, the expression of phosphorylated Smad2 was significantly decreased, followed then by gradual increment till nearly the normal level. Twenty-two weeks after DENA treatment, Smad4 expression in liver tissue decreased markedly as compared with the levels at 8 and 16 weeks. The expressions of Smad4 and phosphorylated Smad2 in the HCC tissue was significantly lower than those in normal liver tissue.

CONCLUSIONHepatocarcinogenesis involves very complex mechanisms, can can be related partially to the decreased Smad4 and phosphorylated Smad2 expression and TGFbeta1 and Smad7 overexpression in advanced stage of liver cirrhosis.

Animals ; Diethylnitrosamine ; Liver Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Smad2 Protein ; metabolism ; Smad4 Protein ; metabolism ; Smad7 Protein ; metabolism ; Transforming Growth Factor beta1 ; genetics ; metabolism

OBJECTIVETo demonstrate the alterations of DPC4/SMAD4/MADH4 gene in paraffin-embedded tissues of pancreatic carcinomas.

METHODSForty-six cases of resected specimens containing carcinomatous tissue and normal pancreatic tissue were analysed for possible DPC4 gene mutations by polymerase chain reaction (PCR)and single-strand conformation polymorphism (SSCP). The DNA sequencing technique was applied to determine the patterns of gene mutation in the PCR-SSCP positive cases. Fifty-six cases of pancreatic carcinoma along with the specimens corresponding normal pancreatic tissues were studied by in situ hybridization (ISH) and immunohistochemistry (IHC) techniques for gene expression in mRNA and protein level.

RESULTSThe homozygous deletion rate of exon 1, 2, 3, 4, 8, 11 of DPC4 gene in pancreatic carcinoma was 28.26%, while the mutation rate of DPC4 gene was 21.74%. In these tumors, there were 3 cases of nonsense mutation, 5 cases of missense mutation, 1 case of deletion and missense mutation, 1 case of insertion mutation. Positive rates of SMAD4 in carcinomatous tissues detected by the ISH and IHC were 53.57% and 58.93% respectively, whereas they were 91.07% and 89.29% in the matched normal tissue respectively. There were significant difference between cancer and normal tissue (P < 0.05). Thrity-two cases were positive of DPC4/SMAD4 with all methods mentioned above, the coincident rate was 87.50% (28/32). The coincidence between gene detection and ISH of SMAD4 was 87.50%, and it was 96.88% between gene detection and IHC of SMAD4. Of all 56 cases, the coincidence of the positive rates of SMAD4 detected by ISH and IHC was 91.07%. No significant difference among the positive rates of DPC4/SMAD4 as detected by the three different techniques (P > 0.05).

CONCLUSIONSThe main mechanisms of inactivation of DPC4 gene in pancreatic carcinoma are homozygous deletion and mutation. The product of DPC4 expression is significantly decreased in cancer group compared with the normal tissues. As a tumor suppressor gene, DPC4 alteration is an important molecular event in pancreatic carcinoma, and probably plays a crucial role in cancer development and progression.

Adult ; Aged ; DNA-Binding Proteins ; genetics ; metabolism ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Pancreatic Neoplasms ; genetics ; pathology ; Paraffin Embedding ; Proto-Oncogenes ; genetics ; RNA, Messenger ; metabolism ; Smad4 Protein ; Trans-Activators ; genetics ; metabolism