A novel hydrogen sulfide-releasing donor, HA-ADT, suppresses the growth of human breast cancer cells through inhibiting the PI3K/AKT/mTOR and Ras/Raf/MEK/ERK signaling pathways.

Breast cancer is one of the most frequent cancers among women worldwide. Hyaluronic acid (HA) is one of the best biopolymers in terms of safety issues and has been widely used in drug delivery and tissue engineering. 5-(4-hydroxyphenyl)-3H-1,2-dithiol-3-thione (ADT-OH) is a commonly used H2S donor. In this study, we designed and synthesized a conjugate, HA-ADT, by connecting HA with ADT-OH through chemical reactions. Our results indicated that HA-ADT could produce more H2S than NaHS and GYY4137. HA-ADT exerted more potent inhibitory effects than NaHS and GYY4137 in the proliferation, viability, migration, and invasion of human breast cancer cells. Similar trends were observed in the apoptosis and the protein levels of phospho (p)-PI3K, p-AKT, p-mTOR, H-RAS, p-RAF, p-MEK, and p-ERK in human breast cancer cells. Furthermore, HA-ADT exhibited more powerful inhibitory effects on the growth of human breast cancer xenograft tumors in nude mice. In conclusion, HA-ADT could suppress the growth of human breast cancer cells through the inhibition of the PI3K/AKT/mTOR and RAS/RAF/MEK/ERK signaling pathways. HA-ADT and its derivatives might be of great potential in the treatment of different types of cancer.

[Angiogenesis of brain after ischemia/reperfusion injury of brain in aged rats and changes in expressions of basic fibroblast growth factor and transformation growth factor-ß1].

OBJECTIVE: To elucidate the mechanism of angiogenesis after cerebral ischemia/reperfusion (I/R) in the aged rats by observing the changes in expressions of basic fibroblast growth factor (bFGF) and transformation growth factor-ß1 (TGF-ß1). METHODS: Young Sprague-Dawley (SD) rats were classified into groups by random digits table, and aged SD rats were stratified by different body weight. Rats were randomly divided into groups of sham operation, ischemia (I) 3 hours, I/R 1, 3, 6, 12 days, with 6 rats in each group. Focal cerebral I/R model was reproduced by intraluminal filament technique. Microvessel density (MVD) of brain tissue, sum area of lumens were observed, and the expressions of bFGF protein, TGF-ß1 protein and TGF-ß1 mRNA were assessed with immunohistochemistry and hybridization in situ. RESULTS: MVD in young model group began to increase at I 3 hours, peaking at I/R 6 days, maintained up to I/R 12 days. MVD in aged model group began to descend at I 3 hours and continued to I/R 12 days. Sum area of lumens in young model group increased markedly at I/R 1 day, gradually lowered at I/R 1-6 days, and increased obviously again at I/R 12 days. Sum area of lumens in aged model group reached peak at I/R 1 day, gradually decreased subsequently. MVD in aged sham operation group were higher than that in young sham operation group (6.88±1.60 vs. 5.50±1.53, P<0.01). MVD and sum area of lumens in aged model group at I/R 1, 3, 6, 12 days were lower than young model group. Expressions of bFGF protein, TGF-ß1 protein in young and aged model group were both gradually up-regulated, all of them reaching peak at I/R 3 days, and lowered gradually at I/R 3-12 days subsequently. Expressions of bFGF protein (grey level) in both aged sham operation group and those of model group at I 3 hours, I/R 1, 3, 12 days were lower than those of young sham operation and those of the model group at the same time points (176.80±5.10 vs. 172.82±1.53, 171.81±2.43 vs. 167.85±2.41, 167.99±5.51 vs. 164.90±2.15, 152.98±4.11 vs. 150.75±1.11, 165.67±3.55 vs. 161.73±1.29, P<0.05 or P<0.01). Expressions of TGF-ß1 protein (grey level) in both aged sham operation and those of model group at I 3 hours, I/R 1, 3, 6, 12 days were all lower than those of young sham operation and those of model group at the same time points (182.69±3.12 vs. 176.13±4.08, 176.89±2.30 vs. 170.56±7.47, 171.74±2.70 vs. 165.43±2.91, 157.17±5.20 vs. 150.43±4.28, 161.72±4.81 vs. 155.37±2.92, 167.69±2.18 vs. 160.28±3.59, all P<0.01). TGF-ß1 mRNA expressions in both young model group and aged model group reached peak at I/R 1 day, gradually lowered subsequently. Expressions of TGF-ß1 mRNA (gray level) in both aged sham operation and those of model group at I 3 hours, I/R 3, 6, 12 days were lower than those of young sham operation and also model group at the same time points (176.51±9.52 vs. 169.09±5.08, 176.75±5.74 vs. 165.36±4.78, 177.33±5.68 vs. 165.25±8.14, 178.46±4.91 vs. 170.51±4.29, 203.95±4.51 vs. 181.98±5.59, all P<0.01). CONCLUSION: Angiogenesis is obviously weak after cerebral I/R in the aged, and the mechanism of which might be related to the down-regulation of expressions of bFGF protein, TGF-ß1 protein and TGF-ß1 mRNA. Aging factor may be one of the main reasons which induce the down regulation of expressions mentioned above.

[Relationship between the changes in ischemia/reperfusion cerebro-microvessel basement membrane injury and gelatinase system in senile rat].

OBJECTIVE: To study the relationship of cerebro-microvessel basement membrane injury and gelatinase system after cerebral ischemia/reperfusion (I/R) in aged rats. METHODS: Cerebral I/R injury model was reproduced by intraluminal silk ligature thrombosis of the middle cerebral artery occlusion (MCAO). Rats were divided randomly into sham control and I/R groups in young rats [ischemia 3 hours (I 3 h) and reperfusion 6 hours (I/R 6 h), 12 hours (I/R 12 h), 24 hours (I/R 24 h), 3 days (I/R 3 d), 6 days (I/R 6 d)], and sham control group and I/R group in aged rats (I 3 h and I/R 6 h, I/R 12 h, I/R 24 h , I/R 3 d, I/R 6 d). The change in cerebro-cortex microvessel basement membrane structure, basement membrane type IV collagen (Col IV) and laminin (LN) contents, matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression in every group were determined with immunohistochemical method and zymogram analysis. RESULTS: With the increase in age, Col IV and LN contents of the microvessel basement membrane were increased, and MMP-2 and MMP-9 expressions were stronger. With prolongation of I/R, the degradation of microvessel basement membrane components (Col IV and LN) was positively correlated with the duration of cerebral I/R. MMP-2 expression was increased gradually, and MMP-9 and TIMP-1 expression increased at the beginning and decreased subsequently. Col IV(I 3 h, I/R 6 h , I/R 12 h), LN (I 3 h, I/R 6-24 h), MMP-2 (I 3 h, I/R 6 h-6 d) and MMP-9 (I 3 h, I/R 6-24 h) expression level in aged rats with I/R injury were higher, and TIMP-1 (I/R 24 h) expression was lower than those in young rats (P<0.05 or P<0.01). In addition, changes in MMP-2 and MMP-9 contents as determined by zymogram analysis method coincided with their immunoexpression. CONCLUSION: With the increase of age, alteration in membrane components of cerebro-microvessel basement membrane in rats is related with MMPs and TIMP. Cerebro-microvessel basement membrane injury is more serious in aged rats than that of young rats. Changes in cerebro-microvessel basement membrane injury in aged rats is related with gelatinase system change.

[Study on changes of neuron apoptosis after focal cerebral ischemia/reperfusion in the aged rats].

OBJECTIVE: To study ultrastructured change and neuron apoptosis after focal cerebral ischemia/reperfusion (I/R) in the aged rats. METHODS: The aged SD rats (20-21 months) and the young (4-5 months) were subjected to 3 hours of middle cerebral artery occulsion with the intraluminal filament technique, followed by reperfusion for 3 hours, 6 hours, 12 hours, 24 hours, 72 hours. The ultrastructure of brain, infarct zone and neuron apoptosis were observed. RESULTS: The cerebral infarct zone increased in the aged rats with ischemia for 3 hours and I/R for 12 hours compared with those in the young. The brain injury was obviously deteriorated with I/R time longer, which was serious in the aged than that in the young. The neuron apoptosis increase with I/R time longer, and showed earlier and lasted longer in the aged. CONCLUSION: The cerebral injury is serious and neuron apoptosis increase shows early and lasts longer.

Preliminary Study on Gene Therapy of PD Monkey Using Microcapsulated Rat Transgenetic Myoblasts.

Rat myoblast cells transfected with tyrosine hydroxylase gene were microcapsulated using the ALG/PLL system. These microcapsulated cells could survive grow and produce tyrosine hydroxylase(TH)for at least two months in vitro. After the implantation of these microcapsules into monkey striatum microcapsulated cells still survived one month more. No obvious gliosis was seen around implanted microcapsules. Then the microcapsules were transplanted into the striatum of PD monkeys and their typical PD rotation numbers were significantly decreased.