Notch ligand Delta-like 1 promotes the metastasis of melanoma by enhancing tumor adhesion.

Notch signaling plays a vital role in tumorigenicity and tumor progression by regulating proliferation, invasion, and the tumor microenvironment. Previous research by our group indicated that Notch ligand Delta-like 1 (Dll1) is involved in angiogenesis in melanoma, and we noticed that it took a longer time to trypsinize Dll1-expressing B16 melanoma cells than the control cells. In this article, we extended our study to investigate the effects of Dll1 on tumor cell adhesion and metastasis. Dll1 overexpression activated Notch signaling in B16 tumor cells and significantly enhanced the adhering capacity of B16 tumor cells both in vitro and in vivo. B16-Dll1 cells also had a higher metastatic potential than their counterpart in the mouse model of lung metastasis. Along with increased Dll1 expression, N-cadherin, but not E-cadherin, was upregulated in B16-Dll1 cells. These data suggested that Notch ligand Dll1 may enhance the adhesion and metastasis of melanoma cells by upregulation of N-cadherin.

Notch ligand Delta-like 1 promotes the metastasis of melanoma by enhancing tumor adhesion

Notch signaling plays a vital role in tumorigenicity and tumor progression by regulating proliferation, invasion, and the tumor microenvironment. Previous research by our group indicated that Notch ligand Delta-like 1 (Dll1) is involved in angiogenesis in melanoma, and we noticed that it took a longer time to trypsinize Dll1-expressing B16 melanoma cells than the control cells. In this article, we extended our study to investigate the effects of Dll1 on tumor cell adhesion and metastasis. Dll1 overexpression activated Notch signaling in B16 tumor cells and significantly enhanced the adhering capacity of B16 tumor cells both in vitro and in vivo. B16-Dll1 cells also had a higher metastatic potential than their counterpart in the mouse model of lung metastasis. Along with increased Dll1 expression, N-cadherin, but not E-cadherin, was upregulated in B16-Dll1 cells. These data suggested that Notch ligand Dll1 may enhance the adhesion and metastasis of melanoma cells by upregulation of N-cadherin.

Selective proapoptotic activity of a secreted recombinant antibody/AIF fusion protein in carcinomas overexpressing HER2.

Apoptosis-inducing factor (AIF) represents a caspase-independent apoptotic pathway in the cell, and a mitochondrial localization sequence-truncated AIF (AIFDelta1-120) can be relocated from the cytoplasm to the nucleus and exhibit a constitutive proapoptotic activity. Here, we generated a chimeric immuno-AIF protein, which comprised an HER2 antibody, a Pseudomonas exotoxin translocation domain and AIFDelta1-120. Human Jurkat cells transfected with the immuno-AIF gene could express and secrete the chimeric protein, which selectively recognized HER2-overexpressing tumor cells and was endocytosed. Subsequent cleavage of truncated AIF from immuno-AIF and its release from the internalized vesicles resulted in apoptosis of tumor cells. Intramuscular injection of the immuno-AIF gene caused significant suppression of tumors and substantially prolonged mice survival in an HER2-overexpressing xenograft tumor model. Our study demonstrates the feasibility of the immuno-AIF gene as a novel approach to treating cancers that overexpress HER2.

[The effect of melatonin on enhancing immune function and inhibiting the ability of NO over-release in morphine dependent mice].

AIM: To observe the effects and mechanism of melatonin (MT) on the immune function of morphine dependent mice. METHODS: A physical dependent mice model was established by repeated subcutaneous injection of morphine. The intensity of morphine withdrawal syndrome was evaluated according to the weight of immune organs, the proliferation reaction of stimulated splenic lymphocytes by Con A, the phagoindex of blood primed macrophages and the content of NO induced in the peritoneal macrophage (pM phi). RESULTS: MT reversed the inhibitory effect of morphine on the proliferation ability of splenic lymphocytes and enhanced the phagocytosis of macrophages of morphine dependent mice obviously and prevented the over-release of NO from pM phi. The enhancing effects of MT on the phagocytosis can be prevented by naloxon. CONCLUSION: MT can significantly enhance the immune function of morphine dependent mice and inhibit NO excessive release from pM phi.

[Influence of intracerebroventricular injection of sodium nitroprusside L-arginine and NG-nitro-L-arginine on cardiovascular activity in conscious rats].

In order to study the cardiovascular effect of NO in conscious rats, sodium nitroprusside (SNP), the precursor of NO (L-Arginine, Arg-Arg) and one of the inhibitor of NOS (NG-nitro-L-arginine, NNLA) were intracerebroventricularly (icv) injected. Our experimental results indicated that, an apparent dose-dependent hypertensive effect was produced by icv administration of SNP (8, 16, 32 and 32 micrograms), a tachycardiac effect was also produced at the same time. In addition, hypertension and tachycardia were produced by icv L-arginine and the dipeptide Arg-Arg. Furthermore a hypotensive and bradycardiac effect can be produced by icv NNLA. These results suggest that there is a positive effect on cardiovascular activity due to increase of endogeneuse NO in the rat brain and a negative effect on cardiovascular activity due to decrease of endogeneuse NO in the rat brain.

[The cardiovascular reactions mediated by TPA and tamoxifen in spinal cord of conscious rats].

Intrathecal administration (ith) of phorbol 12-myristate (TPA), an activator of protein kinase C, (31.24, 26.5, 125 and 250 ng/10 micrograms) to conscious rats produced a marked dose-dependent pressor effect without significant change in heart rate (HR). Intrathecal administration of tamoxifen (3.125, 6.5 and 100 micrograms/10 microliters), one of the inhibitors of protein kinase C, produced a marked dose-dependent hypotensive effect. Intrathecal injection of exogenous DBcAMP (12.5, 25, 50 and 100 micrograms/10 microliters) also increased the mean arterial blood pressure (mABP) and markedly lowered HR. It was further observed that, based on the effect of DBcAMP (25 micrograms/10 microliters), the pressor effect of four doses of TPA can be augmented. The results indicate that TPA in spinal cord may exert hypertensive effect via activation of PKC and tamoxifen may exert a hypotensive effect via inhibition of PKC. In addition, the pressor effect of TPA could be augmented by preadministration of DBcAMP.

[The depressor effect of intracerebroventricular injection of BQ123 and endothelin (ET)--antiserum on hypertensive rats produced by aorta stenosis and hypersaline uptake].

An experimental model of hypertensive rat was made by abdominal aorta stenosis and hypersaline uptake. The blood pressure was significantly decreased by intracerebroventricular injection (i.c.v.) of BQ123 a potent antagonist of ET-1 receptor, in a dose-dependent manner. Negative chronotropic effect on the heart was produced by high dose of BQ123, while the depressor effect was produced by i.c.v. ET-antiserum. These results indicate that endothelin in CNS may play an important role in the pathological physiology of hypertension.

Serotonin receptor subtypes in spinal antinociception in the rat.

The aim of the present study was to clarify the subtypes of serotonin (5-HT) receptors involved in spinal antinociception in the rat. 1) Intrathecal (i.t.) injection of 5-HT (25-200 micrograms) produced a dose-dependent increase in tail-flick latency. 2) Intrathecal injection of fluoxetine, a 5-HT uptake blocker (25-40 micrograms), resulted in a bell-shaped dose-related antinociception with peak effects occurring at 10 micrograms. 3) A bell-shaped antinociceptive effect was obtained by i.t. injection of the 5-HT1A agonist (+)-hydroxy-2-(di-N-propylamino)tetralin (0.25-2 micrograms), with the maximal effect occurring at 0.5 micrograms, which can be prevented by the 5-HT1A antagonist spiperone (25 micrograms i.t.). 4) A similar dose-response curve was obtained following the i.t. injection of the 5-HT1B agonist 1-[3-(trifluoromethyl)phenyl]-piperazine maleate (1-125 micrograms) with the maximal effect observed at 25 micrograms. 5) Neither the 5-HT2 agonist (+/-)-alpha-methyl-5-HT-maleate nor the 5-HT3 agonist (+/-)-2-methyl-5-HT-maleate produced significant antinociceptive effects at doses up to 50 micrograms. Spontaneous tail-flicks emerged at doses higher than 50 micrograms. 6) The antinociceptive effect induced by 5-HT (200 micrograms i.t.) could be attenuated dose-dependently either by the 5-HT1A antagonist spiperone (5 and 25 micrograms i.t.) or by the 5-HT1C/2 antagonist mianserin (0.5-50 micrograms i.t.), but not by the 5-HT2 antagonist 1-(1-naphthyl)piperazine hydrochloride or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate.(ABSTRACT TRUNCATED AT 250 WORDS)

[The characterization of 5-HT1A receptor in the central nervous system of the spontaneously hypertensive rats].

With method of the radio binding assay (RBA), it was observed that in the present work that in normotensive Wistar rats, the specific binding of [3H] 8-OH-DPAT at 2.4 nmol/L concentration was about the same in hippocampus (7.62 +/- 0.24 pmol/mg), hypothalamus (8.18 +/- 0.63 pmol/mg) and lower brain stem (9.11 +/- 0.78 pmol/mg); whereas, in spontaneously hypertensive rats (SHR), these regional specific bindings were 2(+)-3+ times higher. Scatchard analyses showed that the Bmax was also higher than that of normotensive Wistar rats in hippocampus and hypothalamus, whereas the KD in hypothalamus was lower. The differences between SHR and normotensive rats in the 5-HT1A receptor contents in various brain regions appear to be related to one of the linking events in the generation of hypertension.

[The permissive action of glucocorticoid on the analgesic effect of kyotorphin and its analogue].

Kyotorphin (KTP) is an endogenous analgesic dipeptide which does not act on opiate receptors but may induce the release of endogenous opioid met-enkephalin. In order to investigate whether or not glucocorticoids have "permissive action" on KTP, hydrocortisone has been used to examine its action on the analgesic activities of KTP and its retro-isomer (riKTP) by employing thermal irradiation-tail flick method after intracerebroventricular injection. KTP and riKTP showed dose-dependent analgesic activity. Dose of KTP in the range of 6-24 mmol/L were effective, while the dose of riKTP at 6 mmol/L was shown to be ineffective. The analgesia of KTP was higher than that of riKTP. Hydrocortisone alone showed no significant analgesic effect. Linkers by connecting hydrocortisone with KTP or riKTP showed significantly higher analgesic effect compared with the corresponding dipeptides, not only in the duration of analgesia but also in potency. Solutions containing hydrocortisone and any one of the dipeptides exhibited the same effect as the linker. Pretreatment with sc naloxone (10 mg/kg) 15 min before icv of KTP or riKTP (24 mmol/L) could not block the analgesia. These findings implicate that: (1) Glucocorticoids have a permissive action on the analgesia of KTP and its retro-isomer. The glucocorticoids may exert its effects by acting on receptors in the membrane, and thus cause fast membrane effect. (2) KTP may also induce release of substances other than met-enkephalin to participate in the analgesia.

[Effects of different thyroid states on 5-HT1A receptor in adult rat brain].

The effects of dysthyroidism on central 5-HT1A receptor subtype in adult Wistar rats were investigated. Hyperthyroidism and hypothyroidism were respectively produced with the administration of T3 and propylthiouracil (PTU) via gavage for 2 weeks. Heart rate, oxygen consumption, anal temperature and plasma T3 concentration were increased in hyperthyroid rats and decreased in hypothyroid rats significantly. Radioligand binding assay showed that the specific binding of [3H] 8-hydroxy-2-(di-n-propylamino) tetralin ([3H] 8-OH-DPAT) at 0.6 nmol/L concentration was highest in hippocampus, next in cerebral cortex, and lowest in hypothalamus, brain stem and corpus striatum in euthyroid rats. Hyperthyroidism increased the binding significantly in hippocampus but decreased in cortex. No change was found in the other brain regions. Scatchard analyses revealed that the Bmax was increased in hippocampus and decreased in cortex, whereas the KD was not consistently affected in hyperthyroid rats in comparison with that in euthyroid rats. However, there were no significant changes mentioned above in all these brain regions of hypothyroid rats. Our results indicate that there seems to exist an imbalance of the serotonergic activity mediated via 5-HT1A receptor between hippocampus and cerebral cortex in hyperthyroids. This might be one of the mechanisms leading to psychoneural disorders in hyperthyroidism.

[Cardiovascular reactions mediated by 5-HT1A and 5-HT3 receptors in the spinal cord of conscious rats].

Intrathecal administration (ith) of 5-hydroxytryptamine (5-HT, 1.56, 3.125, 6.25 and 12.5 micrograms/10 microliters) to conscious rats produced a marked dose-dependent hypertensive effect without significant change in heart rate (HR). Ith administration of fluoxetine (10 micrograms/microliters), one of the presynaptic reuptake inhibitors of 5-HT, produced a marked increase in the mean arterial blood pressure (mABP). This effect could be prevented by a pretreatment with cinanserin (25 micrograms ith) as a blocker of 5-HT receptor. It was further observed that ith of 8-OH-DAPT (2.5, 5, 10 micrograms/10 microliters), a 5-HT1A receptor agonist, produced a dose-dependent increase of mABP and lowering of HR. However, ith of 5-HT3 receptor agonist 2-Methylserotonin (25, 50, 100 micrograms/10 microliters), decreased mABP markedly without change in HR. The results indicate that 5-HT in the spinal cord may extra hypertensive effect via 5-HT1A receptor and a hypotensive effect via 5-HT3 receptor. This gives a possible explanation about the conflicting reports concerning the effect of 5-HT in the central nervous system on blood pressure.

A multisectoral approach to primary health care in Fujian, China.

The government of Yongan in Fujian province has developed a multisectoral primary health care program in the rural community of Dahu with the aim of reaching "Health for All" by 1993. In keeping with the spirit of the Alma Ata declaration and the tradition of local self-reliance in China, the program has involved the entire community and is financed almost exclusively at the local level. Community leaders were trained in the importance of primary health care so that they could serve as role models. The project includes school health education, domestic hygiene education, reconstruction of homes to separate the kitchen, toilet and animals pens, road construction to eliminate dust, environmental sanitation, occupational health, and the upgrading of health care facilities. A number of local ordinances regarding construction, zoning and smoking have also been instituted. The results of the project's first year of implementation in two villages indicate that construction of the new road is near completion, and access to clean water is almost universal. Gains are also reported in the percentage of the population receiving physical examinations, the number of health stations that now meet state standards, and the number of homes that are constructed according to the new guidelines.