Activity of the morpholino anthracycline 3′-deamino-3′-morpholino-13-deoxo-10-hydroxycarminomycin (MX2) against human tumor colony-forming unitsin vitro

Summary In several preclinical systems, the morpholino anthracycline MX2 has greater antitumor activity than doxorubicin, is less cardiotoxic, and is effective against multidrug resistant cancer cells. We used a human tumor soft-agar cloning assay to test the cytotoxicity of MX2 against single cell suspensions from freshly obtained human tumors. Tumor cells were exposed to MX2 at 0.05 and 0.5 g/ml either for 1 hour (201 specimens; 77 [38%] assessable) or continuously (231 specimens; 91 [39%] assessable). Superior antitumor activity was observed with continuous exposure (19%in vitro response at 0.05 g/ml and 69% at 0.5 g/ml) than with 1-hour exposure (1.3% at 0.05 g/ml and 12% at 0.5 g/ml). Activity was seen against all types of cancer tested including renal (91%), melanoma (88%), ovarian (73%), breast (71%) and non-small-cell lung (67%) cancer at a MX2 concentration of 0.5 g/ml after continuous exposure. If appropriate plasma levels can be achieved in patients, MX2 could have significant clinical activity in patients with those tumors.     

Syntenin‐a promotes spinal cord regeneration following injury in adult zebrafish

In contrast to mammals, adult zebrafish recover locomotor function after spinal cord injury, in part due to the capacity of the central nervous system to repair severed connections. To identify molecular cues that underlie regeneration, we conducted mRNA expression profiling and found that syntenin‐a expression is upregulated in the adult zebrafish spinal cord caudal to the lesion site after injury. Syntenin is a scaffolding protein involved in mammalian cell adhesion and movement, axonal outgrowth, establishment of cell polarity, and protein trafficking. It could thus be expected to be involved in supporting regeneration in fish. Syntenin‐a mRNA and protein are expressed in neurons, glia and newly generated neural cells, and upregulated caudal to the lesion site on days 6 and 11 following spinal cord injury. Treatment of spinal cord‐injured fish with two different antisense morpholinos to knock down syntenin‐a expression resulted in significant inhibition of locomotor recovery at 5 and 6 weeks after injury, when compared to control morpholino‐treated fish. Knock‐down of syntenin‐a reduced regrowth of descending axons from brainstem neurons into the spinal cord caudal to the lesion site. These observations indicate that syntenin‐a is involved in regeneration after traumatic insult to the central nervous system of adult zebrafish, potentially leading to novel insights into the cellular and molecular mechanisms that require activation in the regeneration‐deficient mammalian central nervous system.     

Inhibition of iridovirus protein synthesis and virus replication by antisense morpholino oligonucleotides targeted to the major capsid protein, the 18 kDa immediate-early protein, and a viral homolog of RNA polymerase II

Frog virus 3 (FV3) is a large DNA virus that encodes approximately 100 proteins. Although the general features of FV3 replication are known, the specific roles that most viral proteins play in the virus life cycle have not yet been elucidated. To address the question of viral gene function, antisense morpholino oligonucleotides (asMOs) were used to transiently knock-down expression of specific viral genes and thus infer their role in virus replication. We designed asMOs directed against the major capsid protein (MCP), an 18 kDa immediate-early protein (18K) that was thought to be a viral regulatory protein, and the viral homologue of the largest subunit of RNA polymerase II (vPol-IIalpha). All three asMOs successfully inhibited translation of the targeted protein, and two of the three asMOs resulted in marked phenotypic changes. Knock-down of the MCP resulted in a marked reduction in viral titer without a corresponding drop in the synthesis of other late viral proteins. Transmission electron microscopy (TEM) showed that in cells treated with the anti-MCP MO assembly sites were devoid of viral particles and contained numerous aberrant structures. In contrast, inhibition of 18K synthesis did not block virion formation, suggesting that the 18K protein was not essential for replication of FV3 in fathead minnow (FHM) cells. Finally, consistent with the view that late viral gene expression is catalyzed by a virus-encoded or virus-modified Pol-II-like protein, knock-down of vPol-IIalpha triggered a global decline in late gene expression and virus yields without affecting the synthesis of early viral genes. Collectively, these results demonstrate the utility of using asMOs to elucidate the function of FV3 proteins.     

Blocking expression of AHR2 and ARNT1 in zebrafish larvae protects against cardiac toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

The zebrafish (Danio rerio) has become an attractive vertebrate model for studying developmental processes, and is emerging as a model system for studying the mechanisms by which xenobiotic compounds perturb normal development. Embryos treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) shortly after fertilization exhibit a range of adverse effects on the heart: an early reduction in cardiac myocyte number, followed by a change in heart looping and morphology, with an apparent compaction of the ventricle and overall decrease in heart size. These changes are accompanied by impaired cardiac function including a decrease in cardiac output and eventually irreversible ventricular standstill. The mechanisms involved in mediating effects of TCDD on the heart remain unknown. However, it is widely accepted that aryl hydrocarbon receptor (AHR) activation mediates endpoints of TCDD toxicity in vertebrates. In zebrafish, there are multiple forms of AHR and AHR nuclear translocator protein (ARNT) raising the question about whether different endpoints of TCDD toxicity are mediated by different components of the AHR/ARNT pathway. To address this question we used morpholino oligonucleotide technology to specifically block the expression of zfAHR2, zfARNT1, zfARNT2, and zfCYP1A, and assessed the previously described effects of TCDD on heart morphology, size, and function in the developing morphants. We report that blocking zfAHR2 and zfARNT1 expression provided protection against the TCDD-mediated alteration in heart morphology, reduced cardiac myocyte number, decreased cardiac output and ventricular standstill in zebrafish larvae, while the zfarnt2 and zfcyp1a morpholinos did not block the TCDD-induced cardiac toxicity.     

HPLC法测定盐酸吲哚美辛2-[2-(6-甲氧基-2-萘基)吗啉基]乙酯的平衡溶解度和脂水分配系数

目的:测定盐酸吲哚美辛2-[2-(6-甲氧基-2-萘基)吗啉基]乙酯在乙醇、乙腈、丙酮、乙酸乙酯等溶剂中的平衡溶解度以及在正辛醇-水和正辛醇-缓冲液体系中的表观油水分配系数。方法:采用HPLC法测定盐酸吲哚美辛2-[2-(6-甲氧基-2-萘基)吗啉基]乙酯的浓度,采用摇瓶法测定其表观油水分配系数。结果:25℃时盐酸吲哚美辛2-[2-(6-甲氧基-2-萘基)吗啉基]乙酯在乙醇、乙腈、丙酮、乙酸乙酯中的平衡溶解度分别为31.36,141.50,575.77,598.68 g.L-1。pH=4时此目的化合物的平衡溶解度最小,而表观油水分配系数最大。结论:盐酸吲哚美辛2-[2-(6-甲氧基-2-萘基)吗啉基]乙酯的平衡溶解度及油水分配系数与介质的pH有关。其水溶性较差,脂溶性好。     

A deep intronic mutation in FGB creates a consensus exonic splicing enhancer motif that results in afibrinogenemia caused by aberrant mRNA splicing, which can be corrected in vitro with antisense oligonucleotide treatment

We previously described a novel homozygous point mutation (FGB c.115-600A>G) located deep within intron 1 of the fibrinogen beta gene (FGB), as a likely cause of afibrinogenemia. While this was the only mutation detected, its pathological mechanism was unclear. Here we show the mutation causes the inclusion of a 50-bp cryptic exon by creating a consensus heptad motif recognized by the spliceosome recruiting protein pre-mRNA splicing factor (SF2)/arginine/serine-rich alternative splicing factor (ASF) splicing factor 2/alternative splicing factor (SF2/ASF). Translation of the aberrant mRNA would result in truncation of the Bbeta chain, preventing fibrinogen synthesis. Selective introduction of a second mutation into the enhancer motif abolished the SF2/ASF binding motif and re-established normal pre-mRNA splicing. Subsequent introduction of antisense phosphorodiamidate morpholino oligonucleotides (PMOs) into transfected cells containing the mutant construct blocked the protein-RNA interaction and successfully restored normal splicing ( approximately 50% at 2 microM and approximately 90% at 10 microM). The molecular characterization of this case has revealed a unique disease mechanism, shown the importance of screening for deep intronic mutations, and provided evidence that antisense gene therapy is potentially practical for the treatment of diseases caused by this class of mutation.