Discovery of novel adenylyl cyclase inhibitor by cell-based screening

We screened 2400 compounds to find novel inhibitors of the adenylyl cyclase (AC)-protein kinase A (PKA)-cAMP response-element-binding protein (CREB) signaling pathway (AC/PKA/CREB pathway). Using a multistep cell-based screening system employing split luciferase technique, we narrowed down the candidates effectively from 2400 chemical compounds and identified a novel AC inhibitor (compound 1). Since dysregulation of the AC/PKA/CREB pathway is known to cause diseases not only in the nervous system but also in other organs, compound 1 is expected to be developed as a medicine for these diseases.

Human hepatic metabolism of the anti-osteoporosis drug eldecalcitol involves sterol C4-methyl oxidase

The metabolism of eldecalcitol (ED-71), a 2β-hydroxypropoxylated analog of the active form of vitamin D₃ was investigated by using in vitro systems. ED-71 was metabolized to 1α,2β,25-trihydroxyvitamin D₃ (1α,2β,25(OH)₃D₃) in human small intestine and liver microsomes. To identify the enzymes involved in this metabolism, we examined NADPH-dependent metabolism by recombinant P450 isoforms belonging to the CYP1, 2, and 3 families, and revealed that CYP3A4 had the activity. However, the CYP3A4 -specific inhibitor, ketoconazole, decreased the activity in human liver microsomes by only 36%, suggesting that other enzymes could be involved in ED-71 metabolism. Because metabolism was dramatically inhibited by cyanide, we assumed that sterol C4-methyl oxidase like gene product (SC4MOL) might contribute to the metabolism of ED-71. It is noted that SC4MOL is physiologically essential for cholesterol synthesis. Recombinant human SC4MOL expressed in COS7, Saccharomyces cerevisiae, or Escherichia coli cells converted ED-71 to 1α,2β,25(OH)₃D₃. Furthermore, we evaluated the metabolism of ED-71 by recombinant CYP24A1, which plays an important role in the metabolism of the active form of vitamin D₃ (1α,25(OH)₂D₃) and its analogs. The k_cat/K_m value for 24- or 23-hydroxylation of ED-71 was only 3% of that for 1α,25(OH)₂D₃, indicating that ED-71 was resistant to CYP24A1-dependent catabolism. Among the three enzymes catalyzing ED-71, SC4MOL appears to be most important in the metabolism of ED-71. To the best of our knowledge, this is the first study showing that SC4MOL can function as a drug-metabolizing enzyme. The yeast and E. coli expression systems for SC4MOL could be useful for structure-function analyses of SC4MOL.

Lung cancer associated with an azygos lobe successfully treated with video-assisted thoracoscopic surgery

Primary lung cancer associated with an azygos lobe is extremely rare. Herein, we report the case of a 64-year-old woman with lung adenocarcinoma arising in the right upper lobe with an azygos lobe. The patient underwent a right upper lobectomy and lymph node dissection with video-assisted thoracoscopic surgery. Video-assisted thoracoscopic surgery lobectomy for lung cancer of this variant has yet to be reported. We demonstrate the intraoperative findings and the resected pulmonary lobe. This is the first case of primary lung cancer associated with the azygos lobe treated by lobectomy with video-assisted thoracoscopic surgery.

Measuring CREB activation using bioluminescent probes that detect KID-KIX interaction in living cells

The cyclic adenosine monophosphate response element-binding protein (CREB) is a transcription factor that contributes to memory formation. The transcriptional activity of CREB is induced by its phosphorylation at Ser-133 and subsequent interaction with the CREB-binding protein (CBP)/p300. We designed and optimized firefly split luciferase probe proteins that detect the interaction of the kinase-inducible domain (KID) of CREB and the KIX domain of CBP/p300. The increase in the light intensity of the probe proteins results from the phosphorylation of the responsible serine corresponding to Ser-133 of CREB. Because these proteins have a high signal-to-noise ratio and are nontoxic, it has become possible for the first time to carry out long-term measurement of KID-KIX interaction in living cells. Furthermore, we examined the usefulness of the probe proteins for future high-throughput cell-based drug screening and found several herbal extracts that activated CREB.

Loss of Scribble causes cell competition in mammalian cells

In Drosophila, normal and transformed cells compete with each other for survival in a process called cell competition. However, it is not known whether comparable phenomena also occur in mammals. Scribble is a tumor suppressor protein in Drosophila and mammals. In this study we examine the interface between normal and Scribble-knockdown epithelial cells using Madin-Darby Canine Kidney (MDCK) cells expressing Scribble short hairpin RNA (shRNA) in a tetracycline-inducible manner. We observe that Scribble-knockdown cells undergo apoptosis and are apically extruded from the epithelium when surrounded by normal cells. Apoptosis does not occur when Scribble-knockdown cells are cultured alone, suggesting that the presence of surrounding normal cells induces the cell death. We also show that death of Scribble-knockdown cells occurs independently of apical extrusion. Finally, we demonstrate that apoptosis of Scribble-knockdown cells depends on activation of p38 mitogen-activated protein kinase (MAPK). This is the first demonstration that an oncogenic transformation within an epithelium induces cell competition in a mammalian cell culture system.

Estrogen directly down-regulates the bone-resorbing activity of mature osteoclasts through nuclear estrogen receptor alpha

The decrease in estrogen level that follows the onset ofmenopause causes rapid bone loss, resulting in osteoporosis.However, the mechanism remains unclear, especially concerningthe regulation of bone-resorbing osteoclasts. Here we analyzedthe function of estrogen and its receptor in matureosteoclasts. We found that estrogen directly inhibitedbone-resorption by purified rabbit mature-osteoclasts.Moreover, using a RT-PCR technique, we report that nuclearestrogen receptor (ER) alpha but not ERbeta is expressed in mature osteoclasts. The antisense oligodeoxynucleotide for ERalpha inhibited the reductionin osteoclastic bone-resorbing activity caused by estrogen. We conclude that in part estrogen directly inhibits the bone-resorbing activity of mature osteoclasts through the ERalpha.

Fabrication of nanostripe surface structure by multilayer film deposition combined with micropatterning

Top-down fabrication processes for nanostructures are superior to bottom-up processes from the aspect of long-range order, but have limitations in their processing time and/or material selection. Here we developed a nanopatterning method for 'nanostripes' that incorporates deposition of a multilayer film on a microscale slope array and mechanical polishing. This method is used to fabricate a nanostripe structure consisting of two kinds of materials to form a stripe array on a silicon substrate. Although this nanopatterning method is categorized as a top-down fabrication process, the fabrication efficiency is quite high, because the number of nanostripes is 'multiplied' by the number of multilayered films. Another feature of the nanostripe is renewability; even if the nanostripe surface is damaged, the underlying nanostructure can be exposed and form a similar nanostripe by polishing. The nanostripe structure can be easily applied to a wide range of fields due to its ease of production.

Chondroprotective effect of the bioactive peptide prolyl-hydroxyproline in mouse articular cartilage in vitro and in vivo

OBJECTIVE

To investigate the direct effect of prolyl-hydroxyproline (Pro-Hyp) on chondrocytes under in vivo and in vitro conditions in an attempt to identify Pro-Hyp as the bioactive peptide in collagen hydrolysate (CH).

METHODS

The in vivo effects of CH and Pro-Hyp intake on articular cartilage were studied by microscopic examination of sections of dissected articular cartilage from treated C57BL/6J mice. In this study, mice that were fed diets containing excess phosphorus were used as an in vivo model. This mouse line showed loss of chondrocytes and reduced thickness of articular cartilage, with abnormality of the subchondral bone. The in vitro effects of CH, Pro-Hyp, amino acids and other peptides on proliferation, differentiation, glycosaminoglycan content and mineralization of chondrocytes were determined by MTT activity and staining with alkaline phosphatase, alcian blue and alizarin red. Expression of chondrogenesis-specific genes in ATDC5 cells was determined by semiquantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR).

RESULTS

In vivo, CH and Pro-Hyp inhibited the loss of chondrocytes and thinning of the articular cartilage layer caused by phosphorus-induced degradation. In the in vitro study, CH and Pro-Hyp did not affect chondrocyte proliferation but inhibited their differentiation into mineralized chondrocytes. A combination of amino acids such as proline, hydroxyproline and prolyl-hydroxyprolyl-glycine did not affect chondrocyte proliferation or differentiation. Moreover, CH and Pro-Hyp caused two and threefold increases, respectively, in the staining area of glycosaminoglycan in the extracellular matrix of ATDC5 cells. RT-PCR indicated that Pro-Hyp increased the aggrecan mRNA level approximately twofold and decreased the Runx1 and osteocalcin mRNA levels by two-thirds and one-tenth, respectively.

CONCLUSION

Pro-Hyp is the first bioactive edible peptide derived from CH to be shown to affect chondrocyte differentiation under pathological conditions.

Autocrine and/or paracrine growth of aggressive ATLL cells caused by HGF and c-Met

Adult T-cell leukemia/lymphoma (ATLL) is a neoplasia characterized by the massive invasion of various organs by tumor cells. Previously, we found that expression of the gene for c-Met, a receptor tyrosine kinase for hepatocyte growth factor (HGF), was specific to the acute type among 41 patients with ATLL by microarray. First in the present study, we analyzed the survival of the patients in relation to expression of c-Met and HGF in ATLL cells. Expression of the former but not the latter was associated with poor prognosis. Then, we analyzed the growth of ATLL cells caused by HGF and c-Met. c-Met was expressed in 0/7 chronic ATLLs, 12/14 acute ATLLs, 1/1 IL-2-independent ATLL cell line and 1/7 IL-2-dependent ATLL cell lines as assessed by flow cytometry. HGF induced the proliferation of primary cells from most acute cases examined as well as the c-Met-positive KK1 cell line in contrast to c-Met-negative cells. HGF induced autophosphorylation of c-Met in c-Met-positive cells from an acute case and KK1 cells. The plasma level of HGF was elevated in acute as compared to chronic cases. The levels of HGF and/or IL-6 which induces the production of HGF by stromal cells, were elevated in the supernatant of short-term cultured cells from certain patients with acute or chronic disease. Finally, infiltrated ATLL cells and adjacent stromal cells in liver were shown to be positive for c-Met/HGF and HGF, respectively, in acute cases. Autocrine and/or paracrine growth caused by HGF and c-Met was suggested in aggressive ATLL cells secreting HGF and/or IL-6, respectively.

High-resolution analysis of chromosome copy number alterations in angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, unspecified, with single nucleotide polymorphism-typing microarrays

Angioimmunoblastic T-cell lymphoma (AILT) and peripheral T-cell lymphoma, unspecified (PTCL-u) are relatively frequent subtypes of T- or natural killer cell lymphoma. To characterize the structural anomalies of chromosomes associated with these disorders, we here determined chromosome copy number alterations (CNAs) and loss of heterozygosity (LOH) at >55,000 single nucleotide polymorphism loci for clinical specimens of AILT (n=40) or PTCL-u (n=33). Recurrent copy number gain common to both conditions was detected on chromosomes 8, 9 and 19, whereas common LOH was most frequent for a region of chromosome 2. AILT- or PTCL-u-specific CNAs or LOH were also identified at 21 regions, some spanning only a few hundred base pairs. We also identified prognosis-related CNAs or LOH by several approaches, including Cox's proportional hazard analysis. Among the genes that mapped to such loci, a poor prognosis was linked to overexpression of CARMA1 at 7p22 and of MYCBP2 at 13q22, with both genes being localized within regions of frequent copy number gain. For a frequent LOH region at 2q34, we also identified IKAROS family zinc-finger 2 cDNAs encoding truncated proteins. Our data indicate that AILT and PTCL-u consist of heterogeneous subgroups with distinct transforming genetic alterations.

Divergent cytotoxic effects of PKC412 in combination with conventional antileukemic agents in FLT3 mutation-positive versus -negative leukemia cell lines

FMS-like tyrosine kinase-3 (FLT3) is a new therapeutic target for acute myelocytic leukemia (AML), because FLT3 mutations are the most common genetic alterations in AML and are directly related to leukemogenesis. We studied cytotoxic interactions of a FLT3 inhibitor, PKC412, with eight conventional antileukemic agents (cytarabine, doxorubicin, idarubicin, mitoxantrone, etoposide, 4-hydroperoxy-cyclophosphamide, methotrexate and vincristine) using three leukemia cell lines carrying FLT3 mutations (MOLM13, MOLM14 and MV4-11) and five leukemia cell lines without FLT3 mutations (KOPB-26, THP-1, BALL-1, KG-1 and U937). PKC412 showed synergistic effects with all agents studied except methotrexate for FLT3-mutated cell lines in isobologram analysis. In contrast, PKC412 was rather antagonistic to most drugs, except for 4-hydroperoxy-cyclophosphamide and vincristine, in leukemia cell lines without FLT3 mutations. Cell-cycle analysis revealed that PKC412 induced G1 arrest in leukemia cell lines carrying FLT3 mutations, whereas it arrested cells in G2/M phase in the absence of FLT3 mutations, which may underlie the divergent cytotoxic interactions. These results suggest that the simultaneous administration of PKC412 and other agents except methotrexate is clinically effective against FLT3 mutation-positive leukemias, whereas it would be of little benefit for FLT3 mutation-negative leukemias. Our findings may be of help for the design of PKC412-based combination chemotherapy.

Screening of genes responsible for differentiation of mouse mesenchymal stromal cells by DNA micro-array analysis of C3H10T1/2 and C3H10T1/2-derived cell lines

BACKGROUND

The molecular mechanisms underlying the biologic effects or differentiation of mesenchymal stromal cells (MSC) have not been clarified. Screening for genes differentially expressed at different stages is an important step in determining these molecular mechanisms.

METHODS

In this study, we analyzed the gene expression profiles of C3H10T1/2 (10T1/2) cells and two sublines, A54 (pre-adipocyte) and M1601 (myoblast), as a model of MSC and downstream committed progenitors.

RESULTS

We found up-regulated expression of delta-like-1 (Dlk), Wnt-5a and IL-1 receptor-like-1 (ST2) in 10T1/2 cells; stem cell factor (SCF) and stromal derived factor-1 (SDF-1) in A54 cells; and cardiac muscle-specific gene in M1601 cells. Overexpression of Dlk in A54 cells did not induce any effects on their differentiation into adipocytes. After differentiation into adipocytes, A54 cells reduced the expression of SCF, SDF-1 and Ang-1 as well as the ability to support the formation of a cobblestone appearance.

DISCUSSION

The results suggest that these three lines hae different gene profiles and are a useful system for analyzing the differentiation and function of MSC and progenitor cells.

A genomic analysis of adult T-cell leukemia

Adult T-cell leukemia (ATL) is an intractable malignancy of CD4+ T cells that is etiologically associated with infection by human T-cell leukemia virus-type I. Most individuals in the chronic stage of ATL eventually undergo progression to a highly aggressive acute stage. To clarify the mechanism responsible for this stage progression, we isolated CD4+ cells from individuals in the chronic (n=19) or acute (n=22) stages of ATL and subjected them to profiling of gene expression with DNA microarrays containing >44,000 probe sets. Changes in chromosome copy number were also examined for 24 cell specimens with the use of microarrays harboring approximately 50,000 probe sets. Stage-dependent changes in gene expression profile and chromosome copy number were apparent. Furthermore, expression of the gene for MET, a receptor tyrosine kinase for hepatocyte growth factor (HGF), was shown to be specific to the acute stage of ATL, and the plasma concentration of HGF was increased in individuals in either the acute or chronic stage. HGF induced proliferation of a MET-positive ATL cell line, and this effect was blocked by antibodies to HGF. The HGF-MET signaling pathway is thus a potential therapeutic target for ATL.

Epigenetic silencing of AXIN2 in colorectal carcinoma with microsatellite instability

Mutation or epigenetic silencing of mismatch repair genes, such as MLH1 and MSH2, results in microsatellite instability (MSI) in the genome of a subset of colorectal carcinomas (CRCs). However, little is yet known of genes that directly contribute to tumor formation in such cancers. To characterize MSI-dependent changes in gene expression, we have now compared transcriptomes between fresh CRC specimens positive or negative for MSI (n=10 for each) with the use of high-density oligonucleotide microarrays harboring >44,000 probe sets. Correspondence analysis of the expression patterns of isolated MSI-associated genes revealed that the transcriptome of MSI+ CRCs is clearly distinct from that of MSI- CRCs. Such MSI-associated genes included that for AXIN2, an important component of the WNT signaling pathway. AXIN2 was silenced, apparently as a result of extensive methylation of its promoter region, specifically in MSI+ CRC specimens. Forced expression of AXIN2, either by treatment with 5'-azacytidine or by transfection with AXIN2 cDNA, resulted in rapid cell death in an MSI+ CRC cell line. These data indicate that epigenetic silencing of AXIN2 is specifically associated with carcinogenesis in MSI+ CRCs.

Regulation of Amh during sex determination in chickens: Sox gene expression in male and female gonads

During mammalian sexual development, the SOX9 transcription factor up-regulates expression of the gene encoding anti-Müllerian hormone (AMH), but in chickens, Sox9 gene expression reportedly occurs after the onset of Amh expression. Here, we examined expression of the related gene Sox8 in chicken embryonic gonads during the sex-determining period. We found that cSox8 is expressed at similar levels in both sexes at embryonic day 6 and 7, and only at the anterior tip of the gonad, suggesting that SOX8 is not responsible for the sex-specifi c increase in cAmh gene expression at these stages. We also found that several other chicken Sox genes (cSox3, cSox4 and cSox11) are expressed in embryonic gonads, but at similar levels in both sexes. Our data suggest that the molecular mechanisms involved in the regulation of Amh genes of mouse and chicken are not conserved, despite similar patterns of Amh expression in both species.

DNA microarray analysis of natural killer cell-type lymphoproliferative disease of granular lymphocytes with purified CD3-CD56+ fractions

Natural killer (NK) cell-type lymphoproliferative disease of granular lymphocytes (LDGL) is characterized by the outgrowth of CD3(-)CD16/56(+) NK cells, and can be further subdivided into two distinct categories: aggressive NK cell leukemia (ANKL) and chronic NK lymphocytosis (CNKL). To gain insights into the pathophysiology of NK cell-type LDGL, we here purified CD3(-)CD56(+) fractions from healthy individuals (n=9) and those with CNKL (n=9) or ANKL (n=1), and compared the expression profiles of >12 000 genes. A total of 15 'LDGL-associated genes' were identified, and a correspondence analysis on such genes could clearly indicate that LDGL samples share a 'molecular signature' distinct from that of normal NK cells. With a newly invented class prediction algorithm, 'weighted distance method', all 19 samples received a clinically matched diagnosis, and, furthermore, a detailed cross-validation trial for the prediction of normal or CNKL status could achieve a high accuracy (77.8%). By applying another statistical approach, we could extract other sets of genes, expression of which was specific to either normal or LDGL NK cells. Together with sophisticated statistical methods, gene expression profiling of a background-matched NK cell fraction thus provides us a wealth of information for the LDGL condition.

DNA microarray analysis of hematopoietic stem cell-like fractions from individuals with the M2 subtype of acute myeloid leukemia

Acute myeloid leukemia (AML) may develop de novo or secondarily to myelodysplastic syndrome (MDS). Although the clinical outcome of MDS-related AML is worse than that of de novo AML, it is not easy to differentiate between these two clinical courses without a record of prior MDS. Large-scale profiling of gene expression by DNA microarray analysis is a promising approach with which to identify molecular markers specific to de novo or MDS-related AML. This approach has now been adopted with AC133-positive hematopoietic stem cell-like fractions purified from 10 individuals, each with either de novo or MDS-related AML of the M2 subtype. Sets of genes whose activity was associated with either disease course were identified. Furthermore, on the basis of the expression profiles of these genes, it was possible to predict correctly the clinical diagnosis for 17 (85%) of the 20 cases in a cross-validation trial. Similarly, different sets of genes were identified whose expression level was associated with clinical outcome after induction chemotherapy. These data suggest that, at least in terms of gene expression profiles, de novo AML and MDS-related AML are distinct clinical entities.