HuR-positive stress granules: Potential targets for age-related osteoporosis

Aging impairs osteoblast function and bone turnover, resulting in age-related bone degeneration. Stress granules (SGs) are membrane-less organelles that assemble in response to stress via the recruitment of RNA-binding proteins (RBPs), and have emerged as a novel mechanism in age-related diseases. Here, we identified HuR as a bone-related RBP that aggregated into SGs and facilitated osteogenesis during aging. HuR-positive SG formation increased during osteoblast differentiation, and HuR overexpression mitigated the reduction in SG formation observed in senescent osteoblasts. Moreover, HuR positively regulated the mRNA stability and expression of its target β-catenin by binding and recruiting β-catenin into SGs. As a potential therapeutic target, HuR activator apigenin (API) enhanced its expression and thus aided osteoblasts differentiation. API treatment increased HuR nuclear export, enhanced the recruitment of β-catenin into HuR-positive SGs, facilitated β-catenin nuclear translocation, and contributed osteogenesis. Our findings highlight the roles of HuR and its SGs in promoting osteogenesis during skeletal aging and lay the groundwork for novel therapeutic strategies against age-related skeletal disorders.

Ellagic acid inhibits CDK12 to increase osteoblast differentiation and alleviate osteoporosis in hindlimb-unloaded and ovariectomized mice

BACKGROUND

Osteoporosis is a highly prevalent bone disease occurred commonly in astronauts and postmenopausal women due to mechanical unloading and estrogen deficiency, respectively. At present, there are some traditional Chinese medicine compounds for preventing and treating osteoporosis induced by simulated microgravity, but the detailed components of the traditional Chinese medicines still need to be confirmed and osteoporosis is still untreatable due to a lack of effective small-molecule natural medicine.

PURPOSE

To explore the role of cyclin-dependent kinase 12 (CDK12) in osteoporosis induced by simulated microgravity and the therapeutic effect of CDK12-targeted Ellagic Acid (EA) on osteoporosis.

METHODS

Our previous study has suggested that CDK12 as a potential target for treating and preventing osteoporosis. In this study, the role of CDK12 in osteoblasts and mice bone tissues was further studied under simulated microgravity. And by targeting CDK12, natural small-molecule product EA was screened out based on a large scale through the weighted set similarity (WES) method and the therapeutic effects of EA on osteoporosis was investigated in hindlimb-unloaded (HU) mouse model and ovariectomized (OVX) model.

RESULTS

The results demonstrated that simulated microgravity inhibited bone formation and up-regulated the expression of CDK12. Furthermore, CDK12-siRNA or THZ531 (an inhibitor of CDK 12) promoted osteoblast differentiation, while the overexpression of CDK12 inhibited osteoblasts differentiation. And we further proved that CDK12-targeted EA showed a rescue effect on osteoblast differentiation inhibition caused by simulated microgravity. EA (50 mg·kg^-1·day^-1) daily intragastric administration alleviated the symptoms of osteoporosis and accompanied with the improvement of trabecular bone and cortical bone parameters with significantly overexpression of CDK12.

CONCLUSION

EA efficiently improves osteoporosis by targeting CDK12, which is a suppresser of osteoblast differentiation and a novel therapeutic target for treating osteoporosis.

[Mutational features of immunoglobulin heavy chain variable region gene in patients with chronic lymphocytic leukemia]

Objective: To investigate the mutational features of the immunoglobulin heavy chain variable region (IgHV) gene in patients with chronic lymphocytic leukemia (CLL) using immunophenotypic and molecular genetic methods. Methods: The laboratory results of 266 CLL patients who underwent IgHV gene examination at Sino-US diagnostics laboratory from February 2020 to February 2021 were analyzed for the IgVH mutational status and presence of specific IgVH fragments. In addition, their immunophenotypic, molecular, chromosomal karyotypic, and FISH profiles were investigated and correlated with the IgVH mutational status. Results: Among 266 patients, 172 were male and 94 were female, with a media age of 67 years (20-82 years).There were more patients with mutated IgHV (m-IgHV) than unmutated IgHV (un-IgHV) (69.2%∶30.8%). There was association of VH family and the presence of gene fragments: the overall incidence of VH families including VH3 family (142/266, 53.4%), VH4 family (75/266, 28.2%), and VH1 family (34/266, 12.8%) was about 95%, among which the proportion of VH4-34 (26/266, 9.8%), VH3-23 (25/266, 9.4%), VH3-7 (24/266, 9.0%), and VH4-39 (16/266, 6.0%) was about 35%. VH3-20 and VH3-49 only occurred in un-IgHV (P<0.05). In addition, the expression rates of CD38 (26.3% vs. 3.0%), CD79b (71.1%∶45.5%) and 11q deletion (25.5%∶5.3%) were higher in un-IgHV, and single trisomy 12 (37.9%∶5.6%) were more commonly found in m-IgHV (P<0.05). MYD88 was one of the major mutation genes in m-IgHV, while ATM had the highest mutation rate in un-IgHV. Conclusion: CLL patients have differential expression in terms of IgHV gene mutations, correlating to their immunophenotype and genetics characteristics.

Calycosin prevents bone loss induced by hindlimb unloading

Bone loss induced by microgravity exposure seriously endangers the astronauts’ health, but its countermeasures still have certain limitations. The study aims to find potential protective drugs for the prevention of the microgravity-induced bone loss. Here, we utilized the network pharmacology approach to discover a natural compound calycosin by constructing the compound-target interaction network and analyzing the topological characteristics of the network. Furthermore, the hind limb unloading (HLU) rats’ model was conducted to investigate the potential effects of calycosin in the prevention of bone loss induced by microgravity. The results indicated that calycosin treatment group significantly increased the bone mineral density (BMD), ameliorated the microstructure of femoral trabecular bone, the thickness of cortical bone and the biomechanical properties of the bone in rats, compared that in the HLU group. The analysis of bone turnover markers in serum showed that both the bone formation markers and bone resorption markers decreased after calycosin treatment. Moreover, we found that bone remodeling-related cytokines in serum including IFN-γ, IL-6, IL-8, IL-12, IL-4, IL-10 and TNF-α were partly recovered after calycosin treatment compared with HLU group. In conclusion, calycosin partly recovered hind limb unloading-induced bone loss through the regulation of bone remodeling. These results provided the evidence that calycosin might play an important role in maintaining bone mass in HLU rats, indicating its promising application in the treatment of bone loss induced by microgravity.

MiR-138-5p Targets MACF1 to Aggravate Aging-related Bone Loss

Senile osteoporosis is one of the major health problems in an aging society. Decreased bone formation due to osteoblast dysfunction may be one of the causes of aging-related bone loss. With increasing evidence suggesting that multiple microRNAs (miRNAs) play important roles in osteoblast function, the relationship between miRNAs and senile osteoporosis has become a popular research topic. Previously, we confirmed that mechanoresponsive miR-138-5p negatively regulated bone anabolic action. In this study, the miR-138-5p level was found to be negatively correlated with BMD and osteogenic markers in bone specimens of senile osteoporotic patients by bioinformatic analysis and experimental verification. Furthermore, high miR-138-5p levels aggravated the decrease of aged osteoblast differentiation in vitro and led to worse bone loss in aged osteoblastic miR-138-5p transgenic mice in vivo. We also previously identified that the target of miR-138-5p, microtubule actin cross-linking factor 1 (MACF1), could attenuate senile osteoporosis. Here, miR-138-5p was demonstrated to regulate aged osteoblast differentiation by targeting MACF1. Finally, the therapeutic inhibition of miR-138-5p counteracted the decrease in bone formation and aging-related bone loss in aged mice. Overall, our results highlight the crucial roles and the molecular mechanism of miR-138-5p in aging-related bone loss and may provide a powerful therapeutic target for ameliorating senile osteoporosis.

Piezo Channels: Awesome Mechanosensitive Structures in Cellular Mechanotransduction and Their Role in Bone

Piezo channels are mechanosensitive ion channels located in the cell membrane and function as key cellular mechanotransducers for converting mechanical stimuli into electrochemical signals. Emerged as key molecular detectors of mechanical forces, Piezo channels' functions in bone have attracted more and more attention. Here, we summarize the current knowledge of Piezo channels and review the research advances of Piezo channels' function in bone by highlighting Piezo1's role in bone cells, including osteocyte, bone marrow mesenchymal stem cell (BM-MSC), osteoblast, osteoclast, and chondrocyte. Moreover, the role of Piezo channels in bone diseases is summarized.

[Analysis of fusion gene expression in acute myeloid leukemia]

Objective: To analyze the genetic landscape of multiple fusion genes in patients with de novo acute myeloid leukemia (AML) and investigate the characteristics of immunophenotypes and mutations. Methods: The results of multiple fusion genes from 4192 patients with de novo AML were retrospectively analyzed from 2016 to 2020. In addition, the immunophenotypical data and the mutational results from high-through put method were statistically investigated and correlated as well. Results: ①Among the 52 targets, 29 different types of fusion genes were detected in 1948 patients (46.47%) with AML, which demonstrated an "exponential distribution" . ② As the age increased, the number of patients with fusion gene increased first and then decreased gradually. The total incidence rate of fusion genes and MLL rearrangment in children were significantly higher than those in adults (69.18% vs 44.76%, 15.35% vs 8.36%) . ③The mutations involving FLT3 and RAS signaling pathway contributed most in patients with MLL rearrangment. ④No specific immunophenotypic characteristics were found in AML patients with MLL or NUP98 rearrangements. Conclusion: Nearly half of AML patients were accompanied by specific fusion gene expression, the proportions of different fusion genes in pediatric and adults patients were different by multiple PCR. The gene mutations and immunophenotype of these AML patients have certain rules.

[Clinical and laboratory characteristics in patients with myeloid neoplasms complicated with clonal T large granular lymphocyte proliferation]

Objective: To analyze the clinical manifestations and laboratory features in patients with myeloid neoplasms complicated with clonal T large granular lymphocyte (T-LGL) proliferation. Methods: The clinical data of 5 patients with myeloid neoplasms complicated with clonal T-LGL proliferation from November 2017 to November 2018 in Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College were analyzed retrospectively. Results: The median age was 60 years old. All patients had a history of abnormal peripheral blood cell counts for over 6 months. The absolute lymphocyte count in peripheral blood was less than 1.0×10(9)/L. In addition to the typical T-LGL phenotype, the immunophenotype was heterogenous including CD4(+)CD8(-) in 2 patients, the other 3 CD4(-)CD8(+). Four patients were αβ type T cells, the other one was γδ type. STAT3 mutation was detected in 1 patient by next-generation sequencing, the other 4 cases were negative. Conclusions: Clonal T-LGL proliferation with myeloid neoplasm develops in an indolent manner, mainly in elderly patients. Hemocytopenia is the most common manifestation. The diagnosis of T-LGL proliferation does not have specific criteria, that it should be differentiated from other T cell proliferative disorders, such as T-cell clones of undetermined significance. STAT3 or STAT5b mutation may help distinguish.

[Prognostic factors of cyclosporine A combined with androgen in the treatment of transfusion dependent non-severe aplastic anemia]

目的

调查影响环孢素A（CsA）联合雄激素方案治疗输血依赖非重型再生障碍性贫血(TD-NSAA)获得血液学反应的因素。

方法

回顾性分析2010–2013年连续收治的77例TD-NSAA患者临床资料，单因素和多因素分析影响CsA联合雄激素治疗方案获得血液学反应患者的基线临床和血液学特征。

结果

77例TD-NSAA患者治疗后6个月和12个月获得血液学反应分别为43例（55.8％）和53例（68.8％），单因素分析基线血小板计数［19（6～61）×10⁹/L对13.5（5～45）×10⁹/L，P＝0.001］是影响6个月获得血液学反应的唯一因素；基线血小板计数［18（6～61）×10⁹/L对10.5（5～45）×10⁹/L，P<0.001］、网织红细胞绝对值［0.03（0.01～0.06）×10¹²/L对0.03（0.02～0.06）×10¹²/L，P＝0.043］、血小板输注依赖（P＝0.007）和红细胞及血小板输注依赖（P＝0.012）为治疗后12个月能否获得血液学反应相关因素。多因素分析显示基线血小板水平为获得血液学反应独立影响因素（P值分别为0.010和0.009）。受试者工作特征曲线（ROC曲线）方法显示基线PLT界值为15.5×10⁹/L。

结论

TD-NSAA患者初诊时较高的血小板基线水平、网织红细胞基线水平和不伴血小板输注依赖均提示预后较好，血小板水平≥15.5×10⁹/L时可以考虑采用CsA联合雄激素治疗。

[Application of immunophenotypic analysis and molecular genetics in the diagnosis of acute promyelocytic leukemia]

目的

研究免疫表型分析及分子遗传学在急性早幼粒细胞白血病（APL）诊断中的应用价值。

方法

对2012年5月–2017年12月门诊或住院的798例APL患者的流式细胞术（FCM）免疫分型、染色体核型及染色体荧光原位杂交（FISH）进行回顾性分析，并深入研究FCM免疫表型及分子遗传学在APL诊断中的应用价值。

结果

FCM诊断APL敏感性为91.9%，特异性为98.7%。APL具有独特免疫表型特点：典型APL的表型为侧向（SSC）偏大，CD34和HLA-DR表达缺失，表达或强表达CD33，均一表达CD13、CD9、CD123，可伴有CD56、CD7、CD2的表达。约10%的患者为非典型APL表型，一般伴有CD34和（或）HLA-DR表达，SSC减小，经常伴有CD2表达，而FCM免疫分型很难明确诊断为APL，需要依赖遗传学或者分子生物学检查结果。约1/3的患者除存在t（15;17）（q22;q21）外，还存在额外染色体异常；伴有t（15；17）的复杂核型、变异易位或者t（11;17）、t（5;17）等变异型的APL，FCM表型与单纯t（15；17）APL差异无统计学意义（P>0.05）。

结论

FCM能够快速诊断APL，伴有额外染色体异常患者和单纯t（15；17）患者FCM免疫表型没有明显差异。遗传学是诊断APL的金标准，免疫分型中约10%的患者依赖于分子遗传学来确诊。

[Screening of adult Ph-like acute lymphoblastic leukemia by multiplex real-time quantitative PCR]

目的

探讨多重实时荧光定量PCR法早期、快速筛查Ph样急性淋巴细胞白血病（ALL）的可行性，了解Ph样ALL的临床特征及预后。

方法

2010年10月至2016年3月收治的118例初诊成人B-ALL患者纳入研究，利用多重实时荧光定量PCR法检测其中58例BCR-ABL融合基因和MLL重排均阴性患者Ph样相关融合基因及细胞因子受体样因子2（CRLF2）表达情况。比较分析Ph样融合基因阳性和（或）CRLF2高表达患者的临床特征、疗效和预后。

结果

检出Ph样融合基因阳性患者9例（9/58，15.5%），CRLF2高表达患者10例（10/58，17.2%）。Ph样融合基因阳性和（或）CRLF2高表达组、Ph阳性组、MLL重排阳性组以及其他患者组在年龄、WBC、免疫分型、细胞遗传学、危险度分组方面差异有统计学意义（P值均<0.01）。四组患者的2年总生存率分别为65%、47%、64%、74%（P=0.043），2年无复发生存率分别为51%、39%、62%、70%（P=0.010）。

结论

采用多重实时荧光定量PCR法筛查Ph样ALL患者可行，Ph样ALL患者预后较差。

[Targeted sequencing analysis of hyper-eosinophilic syndrome and chronic eosinophilic leukemia]

Objective: Analysis of the molecular characteristics of eosinophilia. Methods: Targeting sequence to 24 patients with chronic eosinophilic leukemia (CEL) with rearrangement of PDGFRA, PDGFRB, or FGFR1 and 62 patients with hyper-eosinophilic syndrome (HES). Mutation annotation and analysis of amino acid mutation using authoritative databases to speculate on possible pathogenic mutation. Results: Thirty-seven kinds of clonal variant were detected from 17 patients with CEL, no recurrent mutation site and hot spot region were found. No pathogenic mutation was detected in 19 patients with PDGFRA rearrangement, but pathogenic mutations of ASXL1, RUNX1 and NRAS were detected from 2 patients with FGFR1 rearrangement who progressed to acute myeloid leukemia and 1 patient with PDGFRB rearrangement who progressed to T lymphoblastic lymphoma, respectively. One hundred and two kinds of clonal abnormalities were detected in 49 patients with HES. The main hot spot mutation regions included: CEBPA Exon1, TET2 Exon3, ASXL1 Exon12, IDH1 Y208C, and FGFR3 L164V. CRRLF2 P224L and PDGFRB R370C point mutations were detected separately in 2 patients with HES who treated with imatinib monotherapy and achieved hematologic remission. Conclusion: The pathogenesis of CEL with PDGFRA, PDGFRB or FGFR1 rearrangement is usually single, and the progression of the disease may involve other driver mutation. A variety of genes with hot mutation regions may be involved in the pathogenesis of HES, and some mutation sites are sensitive to tyrosine kinase inhibitors.

[Spectrum of somatic mutations and their prognostic significance in adult patients with B cell acute lymphoblastic leukemia]

Objective: To investigate the spectrum of gene mutations in adult patients with B-acute lymphoblastic leukemia (B-ALL), and to analyze the influences of different gene mutations on prognosis. Methods: DNA samples from 113 adult B-ALL patients who administered from June 2009 to September 2015 were collected. Target-specific next generation sequencing (NGS) approach was used to analyze the mutations of 112 genes (focused on the specific mutational hotspots) and all putative mutations were compared against multiple databases to calculate the frequency spectrum. The impact of gene mutation on the patients' overall survival (OS) and recurrence free survival (RFS) was analyzed by the putative mutations through Kaplan-Meier, and Cox regression methods. Results: Of the 113 patients, 103 (92.0%) harbored at least one mutation and 29 (25.6%) harbored more than 3 genes mutation. The five most frequently mutated genes in B-ALL are SF1, FAT1, MPL, PTPN11 and NRAS. Gene mutations are different between Ph+ B-ALL and Ph- B-ALL patients. Ph- B-ALL patients with JAK-STAT signal pathway related gene mutation, such as JAK1/JAK2 mutation showed a poor prognosis compared to the patients without mutation (OS: P=0.011, 0.001; RFS: P=0.014,<0.001). Patients with PTPN11 mutation showed better survival than those without mutation, but the difference was not statistically significant (P value > 0.05). Besides, in Ph+ B-ALL patients whose epigenetic modifications related signaling pathway genes were affected, they had a worse prognosis (OS: P=0.038; RFS: P=0.047). Conclusion: Gene mutations are common in adult ALL patients, a variety of signaling pathways are involved. The frequency and spectrum are varied in different types of B-ALL. JAK family gene mutation usually indicates poor prognosis. The co-occurrence of somatic mutations in adult B-ALL patients indicate the genetic complex and instability of adult B-ALL patients.

[Clinical characteristics of high-grade B-cell lymphomas with rearrangement of MYC, bcl-6 and bcl-2]

Objective: To investigate the clinicopathologic features of patients with high-grade B-cell lymphomas (HGBL) that have rearrangements of MYC, bcl-6 and bcl-2. Methods: One hundred and fifty-eight B-cell lymphomas patients from Institute of Hematology and Blood Diseases Hospital from January 2016 to April 2017 were detected by fluorescence in situ hybridization (FISH) with double color split-apart probes. Results: Among 158 B-cell lymphomas, 3 cases with MYC, bcl-2 and bcl-6 rearrangements were identified, 1 of which also had CCND1/IgH translocation. All three patients were of older age, with poor prognostic parameters, multiple organs involvements, elevated LDH and advanced-tumor stage. Two of the three patients were treated with high-intensity chemotherapy and had no remission with an overall survival of 9 months and 11 months respectively. One patient had follow-up with no treatment. Histologically, all three cases showed a spectrum of morphologic features. Although initially categorized as lymphoblastic lymphoma, diffuse large lymphoma and mantle cell lymphoma respectively, two cases were associated with germinal center B-cell (GCB) immunophenotype and 1 case with non-GCB immunophenotype. They had a high proliferation index as assessed by immunostaining for Ki-67 (60%-90%). Conclusions: MYC(+) bcl-2(+) bcl-6(+) HGBL is an aggressive disease with multiple organ involvement, high serum LDH levels, advanced stage disease, poor prognosis and shorter patient survival. The diagnosis should be made by histopathology combined with FISH analysis. Its separation from other types of B cell large cell lymphoma is of clinical importance.

A novel allele HLA-B*27:149 identified by sequence-based typing in a Chinese individual

HLA-B*27:149 differs from HLA-B*27:04:01 (488C->T, exon 3, A139V).

[Clinicopathologic characteristics of plasma cell myeloma with marrow fibrosis]

Objective: To study the clinicopathologic features of plasma cell myeloma(PCM) with bone marrow fibrosis (MF). Methods: The clinicopathologic data of 175 cases of newly diagnosed PCM patients were retrospectively analyzed. Based on reticular fiber staining, these cases were divided into PCM-MF and non-PCM-MF groups. Results: Sixty-three cases were PCM-MF(36%), 112 were non-PCM-MF (64%). No statistical difference in gender, age, hemoglobin level, platelet counts, the classification of immunoglobulin, ISS staging, immunohistochemical phenotypes and genetic features was found between PCM-MF and non-PCM-MF groups (P>0.05). Compared to non-PCM-MF group, lactate dehydrogenase (LDH)level and renal impairmentrate were higher in PCM-MF group (P<0.05). The degree of bone marrow hyperplasia, the percentage of myeloma cells and cells with plasmablastic morphology were significantly higher in PCM-MF group(P<0.05). Conclusion: The higher LDH level, renal impairment rate, and more significant bone marrow hyperplasia, proliferation of plasma cells and plasmablastic myeloma cells infiltration indicate poor prognosis of PCM-MF patients.

Identification of a novel HLA-C*06 variant allele, HLA-C*06:166, by sequence-based typing in a Chinese individual

HLA-C*06:166 differs from HLA-C*06:02:01:01 (146T → C, exon 2, V25A).

[Characterization of mutational pattern in patients with Ph negative myeloproliferative neoplasms]

OBJECTIVE

To characterize the molecular profile in patients with Ph negative myeloproliferative neoplasms (MPN) by exploring 49 gene mutations.

METHODS

Targeted gene sequencing were performed to analyze 49 MPN-associated genes in 51 patients with Ph negative MPN, of which CARL (exon 9), NPM1 (exon 12) and CEBPA (TAD, BZIP domains) were investigated by using Sanger sequencing simultaneously, while FLT3-ITD was assessed by PCR method.

RESULTS

Mutations were detected in 73.5% (36/49) of genes, and the mutational rates of JAK2-V617F, CALR (exon 9) and MPL were 60.8%(31/51), 7.8%(4/51) and 7.8%(4/51) respectively, whereas the mutational rates of ASXL1, SETBP1, and SF3B1 were around 10%. In addition, 96.1% (49/51) of patients harbored at least one mutation, and more than half of the patients (52.9%, 27/51) possessed 3 or 4 gene mutations. The amount of gene mutations was significantly higher in patients with JAK2-V617F mutation than those without JAK2-V617F or CALR (exon 9) mutation (P<0.05). The last finding was that there was no statistically significant difference in the amount of mutations among four MPN subtypes (PV, ET, PMF, and MPN-U).

CONCLUSION

Most patients with Ph negative MPN possesses three or more gene mutations, with various mutational profiles.

A new HLA-B allele, B*52:44, sequenced in a Chinese individual

One nucleotide replacement in codon 154 (GAG>GAT) of HLA-B*52:01:01:01 results in a novel allele formation, HLA-B*52:44.

Sequence-based typing identification of a novel HLA-A*33:95 variant in a Chinese family

One nucleotide replacement in codon 17 (CGC>CAC) of HLA-A*33:03:01 results in a novel allele, HLA-A*33:95.

Characterization of G3BPs: tissue specific expression, chromosomal localisation and rasGAP(120) binding studies

The G3BP (ras-GTPase-Activating Protein SH3-Domain-Binding Protein) family of proteins has been implicated in both signal transduction and RNA-metabolism. We have previously identified human G3BP-1, G3BP-2, and mouse G3BP-2. Here, we report the cloning of mouse G3BP-1, the discovery of two alternatively spliced isoforms of mouse, and human G3BP-2 (G3BP-2a and G3BP-2b), and the chromosomal localisation of human G3BP-1 and G3BP-2, which map to 5q14.2-5q33.3 and 4q12-4q24 respectively. We mapped the rasGAP(120) interactive region of the G3BP-2 isoforms and show that both G3BP-2a and G3BP-2b use an N-terminal NTF2-like domain for rasGAP(120) binding rather than several available proline-rich (PxxP) motifs found in members of the G3BPs. Furthermore, we have characterized the protein expression of both G3BP-1 and G3BP-2a/b in adult mouse tissues, and show them to be both tissue and isoform specific.

Growth inhibition and antimetastatic effect of antisense poly-DNP-RNA on human breast cancer cells

The RNase-resistant and membrane-permeable antisense poly-2'-O-(2,4-dinitrophenyl)-oligoribonucleotides (poly-DNP-RNA) against RIalpha subunit of protein kinase A (RIalpha/PKA) has been used to inhibit the growth of human breast cancer MDA-MB-231 cells in vitro and in vivo. This antisense poly-DNP-RNA, with oligonucleotide sequence GGGCGUGCCUCCUCACUGGC, was found to be an effective concentration-dependent inhibitor of MDA-MB-231 cell line, whereas the control poly-DNP-RNAs with either random or sense sequence were found completely inactive. In situ hybridization studies showed that this antisense inhibitor can permeate spontaneously into MDA-MB-231 cells and distribute itself throughout the cytoplasm. Intraperitoneal administration of this antisense RIalpha poly-DNP-RNA to SCID mice with transplanted MDA-MB-231 cells was found to inhibit the growth of the xenografts in a concentration-dependent way, prevent metastasis, and drastically reduce mortality.

Specific inhibition of breast cancer cells by antisense poly-DNP-oligoribonucleotides and targeted apoptosis

Two membrane-permeable and RNase-resistant antisense poly-2'-O-(2,4-dinitrophenyl)-oligoribonucleotides (poly-DNP-RNAs) have been synthesized as inhibitors of human breast cancer, with nucleotide sequences complementary to the genes of RIalpha subunit of protein kinase A (RIalpha/PKA) and erbB-2, respectively. Both compounds inhibit the proliferation of SK-Br-3 breast cancer cells in culture above the concentration of 10 microg/ml, but have no effect on nontumorigenic MCF-10A breast cells. These antisense inhibitors also block the cell colony formation in methylcellulose medium, whereas the control poly-DNP-RNA with either random or sense sequence has no effect. RT-PCR data show that the antisense inhibition decreases the concentration of the mRNA. TdT-mediated dUTP nick-end labeling (TUNEL) fluorescence assay indicates that the targeted antisense inhibition by poly-DNP-RNAs leads to apoptosis of SK-Br-3 cells but does not affect nontumorigenic MCF-10A cells. The control poly-DNP-RNAs with random or sense nucleotide sequence are completely inactive.

Cloning and expression analysis of a novel mouse gene with sequence similarity to the Drosophila fat facets gene

The Drosophila fat facets (faf) gene is a ubiquitin-specific protease necessary for the normal development of the eye and of the syncytial stage embryo in the fly. Using a gene trap approach in embryonic stem cells we have isolated a murine gene with extensive sequence similarity to the Drosophila faf gene and called it Fam (fat facets in mouse). The putative mouse protein shows colinearity and a high degree of sequence identity to the Drosophila protein over almost its entire length of 2554 amino acids. The two enzymatic sites characteristic of ubiquitin-specific proteases are very highly conserved between mice and Drosophila and this conservation extends to yeast. Fam is expressed in a complex pattern during postimplantation development. In situ hybridisation detected Fam transcripts in the rapidly expanding cell populations of gastrulating and neurulating embryos, in post-mitotic cells of the CNS as well as in the apoptotic regions between the digits, indicating that it is not associated with a single developmental or cellular event. The strong sequence similarity to faf and the developmentally regulated expression pattern suggest that Fam and the ubiquitin pathway may play a role in determining cell fate in mammals, as has been established for Drosophila.