KIF3A inhibits nasopharyngeal carcinoma proliferation, migration and invasion by interacting with ß-catenin to suppress its nuclear accumulation.

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor prevalent in southern China and Southeast Asia. Previous studies have shown that Kinesin Family Member 3A (KIF3A) plays a critical role in the oncogenesis of various cancer types. However, the role of KIF3A in NPC tumorigenesis and the mechanism underlying its function have not been reported. In this study, we found that KIF3A was significantly downregulated in NPC cells and tissues, and KIF3A expression in NPC patients was associated with tumor stage and was positively corrected with overall survival. In vitro and in vivo experiments indicated that overexpression of KIF3A inhibited NPC cell proliferation, migration, and invasion. Mechanistic studies found that KIF3A bound ß-catenin and attenuated ß-catenin aggregation in the nucleus. Moreover, rescue experiments demonstrated that the inhibitory effect of KIF3A on NPC proliferation, migration and invasion was partially dependent on ß-catenin. Taken together, our data suggest that KIF3A interacts with ß-catenin and attenuates NPC proliferation, migration, and invasion by suppressing the intranuclear aggregation of ß-catenin. KIF3A may be a promising therapeutic target of patients with NPC.

Novel Chiral Ru(II) Complexes as Potential c-myc G-quadruplex DNA Stabilizers Inducing DNA Damage to Suppress Triple-Negative Breast Cancer Progression.

Currently, effective drugs for triple-negative breast cancer (TNBC) are lacking in clinics. c-myc is one of the core members during TNBC tumorigenesis, and G-rich sequences in the promoter region can form a G-quadruplex conformation, indicating that the c-myc inhibitor is a possible strategy to fight cancer. Herein, a series of chiral ruthenium(II) complexes ([Ru(bpy)2(DPPZ-R)](ClO4)2, Λ/Δ-1: R = -H, Λ/Δ-2: R = -Br, Λ/Δ-3: R = -C≡C(C6H4)NH2) were researched based on their interaction with c-myc G-quadruplex DNA. Λ-3 and Δ-3 show high affinity and stability to decrease their replication. Additional studies showed that Λ-3 and Δ-3 exhibit higher inhibition against different tumor cells than other molecules. Δ-3 decreases the viability of MDA-MB-231 cells with an IC50 of 25.51 µM, which is comparable with that of cisplatin, with an IC50 of 25.9 µM. Moreover, Δ-3 exhibits acceptable cytotoxic activity against MDA-MB-231 cells in a zebrafish xenograft breast cancer model. Further studies suggested that Δ-3 decreases the viability of MDA-MB-231 cells predominantly through DNA-damage-mediated apoptosis, which may be because Δ-3 can induce DNA damage. In summary, the results indicate that Ru(II) complexes containing alkinyl groups can be developed as c-myc G-quadruplex DNA binders to block TNBC progression.

Expression of hydrogen sulfide synthases and Hh signaling pathway components correlate with the clinicopathological characteristics of papillary thyroid cancer patients.

OBJECTIVE: To examine whether the expression levels of endogenous H2S synthases and hedgehog (Hh) signaling pathway components correlate with the clinicopathological characteristics of papillary thyroid cancer (PTC) patients. METHODS: A retrospective analysis was conducted of clinicopathological data obtained from 176 patients diagnosed with PTC, and immunohistochemical methods were used to detect the expression levels of endogenous H2S synthases cystathionine γ-lyase (CSE), cystathionine ß-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (MPST), as well as three molecules in the Hh signaling pathway: sonic hedgehog (SHH), patched (PTCH), and smoothened (SMO). Specimens of PTC tissue (n=176) and normal para-cancerous thyroid tissue (n=134) were obtained from 176 patients who underwent a total thyroidectomy or thyroid glandular follicle and isthmus resection and analyzed by immunohistochemical methods for their levels of CSE, CBS, MPST, SHH, PTCH, and SMO expression. RESULTS: We found that CSE was overexpressed in PTC tissues, while CBS and MPST were only slightly expressed in PTC tissues at levels similar to those in adjacent normal tissues. The levels of CSE expression were positively correlated with tumor size, extrathyroidal extension (ETE), and lymph node metastasis (LNM), but were not correlated with patient gender, age, or TNM stage. SHH, PTCH, and SMO Hh signaling pathway components were widely expressed in PTC tissues, and their expression correlated with larger tumor size, ETE, and LNM, but not with patient gender, age, or TNM stage, suggesting that activation of the Hh signaling pathway is involved in thyroid tumor progression. CONCLUSIONS: These data suggest that a high level of CSE expression accompanied by Hh signaling pathway activation is involved in the pathogenesis and progression of PTC.

Spinal MCP-1 contributes to the development of morphine antinociceptive tolerance in rats.

BACKGROUND: The chemokine monocyte chemoattractant protein-1 (MCP-1) has been shown to contribute to neuropathic pain. However, whether MCP-1 is involved in the development of morphine antinociceptive tolerance is incompletely understood. METHODS: Morphine antinociceptive tolerance was induced by intrathecal administration of 15 µg of morphine daily for 7 days. Immunohistochemistry was used to test the changes in the morphology of spinal MCP-1 immunoreactivity and OX-42-IR. The role of MCP-1 in morphine antinociceptive tolerance is explored by hot-water tail-flick test. RESULTS: Our findings showed that intrathecal chronic morphine exposure obviously increased MCP-1 immunoreactivity in the spinal cord. Moreover, the increased MCP-1 immunoreactivity was observed mainly in the spinal neurons. Intrathecal injections of MCP-1-neutralizing antibody significantly reduced the development of morphine antinociceptive tolerance, suggesting that spinal neuronal MCP-1 contributes to tolerance to morphine antinociception. Treatment with MCP-1-neutralizing antibody also reduced the spinal microglial activation induced by chronic morphine treatment. CONCLUSIONS: This study revealed for the first time that spinal neuronal MCP-1 is a key mediator of the spinal microglial activation and that spinal MCP-1 is involved in morphine antinociceptive tolerance. Inhibition of MCP-1 may provide a new therapy for morphine tolerance management.

Heat shock protein 90 mediates cytoprotection by H2S against chemical hypoxia-induced injury in PC12 cells.

1. Increasing evidence indicates that hydrogen sulphide (H2S) may serve as an important biological cytoprotective agent. Heat shock protein (Hsp) 90 can attenuate stress-induced injury. However, whether Hsp90 mediates the cytoprotective effect of H2S against chemical hypoxia-induced injury in PC12 cells is not known. 2. In the present study, CoCl2 (a chemical hypoxia mimetic) was used to treat PC12 cells to create a model of chemical hypoxia. To explore the role of Hsp90 in the cytoprotection afforded by H2S against chemical hypoxia-induced injury, 2 µmol/L 17-allylaminogeldanamycin (17-AAG), a selective inhibitor of Hsp90, was administered for 30 min prior to preconditioning with 400 µmol/L NaHS, followed by chemical hypoxia. 3. Cobalt chloride reduced cell viability (by 52.7 ± 1.5%), increased PC12 cell apoptosis (by 42.1 ± 1.5%), induced reactive oxygen species (ROS) by 3.79% compared with control and induced the dissipation of mitochondrial membrane potential (MMP) by 2.56% compared with control. 4. Pretreatment of PC12 cells with 100-400 µmol/L sodium hydrosulphide (NaHS), an H2S donor, for 3 h prior to exposure to 600 µmol/L CoCl2 provided significant, concentration-dependant protection to PC12 cells against CoCl2-induced cytotoxicity. Specifically, pretreatment of PC12 cells with 400 µmol/L NaHS decreased apoptosis to 16.77 ± 1.77% and blocked the CoCl2-induced increase in ROS production and loss of MMP. 5. At 400 µmol/L, NaHS upregulated Hsp90 in a time-dependant manner (over the period 0-180 min). In addition to its effects on Hsp90 expression, NaHS pretreatment of PC12 cells augmented the overexpression of Hsp90 induced by 600 µmol/L CoCl2 by 1.38-fold (P < 0.01). 6. Treatment of PC12 cells with 2 µmol/L 17-AAG for 30 min prior to NaHS pretreatment blocked the overexpression of Hsp90 induced by NaHS preconditioning, as evidenced by decreased cell viability (by 54.2 + 1.2%; P < 0.01), increased PC12 cell apoptosis (by 36.6 ± 1.2%; P < 0.01) and increasing ROS production. 7. The findings of the present study provide novel evidence that Hsp90 mediates H2S-induced neuroprotection against chemical hypoxia-induced injury via anti-oxidant and anti-apoptotic effects.

Hydrogen sulphide protects H9c2 cells against chemical hypoxia-induced injury.

1. The aim of the present study was to investigate the effect of hydrogen sulphide (H(2)S) on cobalt chloride (CoCl(2))-induced injury in H9c2 embryonic rat cardiac cells. 2. After 36 h incubation in the presence of 600 micromol/L CoCl(2), reduced cell viability of H9c2 cells was observed, as well as the induction of apoptosis. In addition, CoCl(2) (600 micromol/L) enhanced the production of reactive oxygen species (ROS) and the expression of cleaved caspase 3, induced a loss of mitochondrial membrane potential (MMP) and decreased reduced glutathione (GSH) production. These results suggest that CoCl(2) induces similar responses to hypoxia/ischaemia. 3. Pretreatment of cells with 400 micromol/L NaHS (a H(2)S donor) for 30 min prior to exposure to CoCl(2) (600 micromol/L) significantly protected H9c2 cells against CoCl(2)-induced injury. Specifically, increased cell viability and decreased apoptosis were observed. In addition, NaHS pretreatment blocked the CoCl(2)-induced increases in ROS production and cleaved caspase 3 expression, as well as the decreases in GSH production and loss of MMP. 4. Pretreatment of cells with 2000 micromol/L N-acetylcysteine (NAC), a ROS scavenger, for 1 h prior to CoCl(2) exposure significantly protected H9c2 cells against CoCl(2)-induced injury, specifically enhancing cell viability, decreasing ROS production and preventing loss of MMP. 5. The findings of the present study suggest that H(2)S protects H9c2 cells against CoCl(2)-induced injury by suppressing oxidative stress and caspase 3 activation.

[Estrogen protects the dopaminergic neurons in substantia nigra against damage induced by 6-hydroxydopamine].

Substantial evidence strongly implies that sensory gating P50 (also called P50 auditory evoked potential, P50) and dopaminergic neurotransmitters are related. In animal experiment, P50 can be recorded in an awake and quiet state with freedom of movement. Until now there is lack of animal experimental data on the supportive effect of estrogen on function of dopaminergic neurons in substantia nigra (SN) in physiological state. In the present study, female Sprague-Dawley (SD) rats were used as subjects. The animals were divided randomly into four groups: (1) control group (normal animals); (2) Parkinson's disease (PD) model group: the right SN was lesioned with 6-hydroxydopamine (6-OHDA); (3) PD model with bilateral ovariectomized group (OVX-PD): bilateral ovariectomy was performed before administration with 6-OHDA; (4) estrogen + PD model with bilateral ovariectomized group (OVX-E(2)-PD): physiological dose of estrogen was given to the bilateral ovariectomy animals before administration with 6-OHDA. P50 induced by two brief acoustic stimuli were recorded in the right SN and the number of TH(+) dopaminergic neurons in the SN stained by immunohistochemistry was calculated after the determination of P50. The results showed that in the PD model group, the testing/conditioning (T/C) ratio of P50 decreased by 40.60% and the number of TH(+) cells in the right SN decreased by 64.74% as compared with that in the control group (P<0.01); In the OVX-PD group, the T/C ratio of P50 decreased by 45.88% and the number of TH(+) cells was reduced by 57.26% as compared with that in the PD group (P<0.01). Administration with 6-OHDA into the SN pars compacta of ovariectomized rats caused more decrease in the number of TH(+) cells as well as more damage to the function of sensory gating in SN. While in OVX-E(2)-PD group, intramuscular injection with estrogen at physiological dose 3 d before 6-OHDA administration decreased the degree of damage to the SN functionally and morphologically, and its degree of injury corresponded to PD group. These results indicate that the mechanism of protection of dopaminergic neurons in the SN provided by physiological level of estrogen is by promoting the resistibility of the neurons to harmful stimulation. If the gonads are resected resulting in a lack of estrogen, the degree of injury to the function and morphology of dopaminergic neurons in SN induced by 6-OHDA increases. Replacement of estrogen at physiological level on time is necessary. Sensory gating P50 in SN may reflect dynamically the protection of estrogen against dopaminergic neurons depletion in vivo.

[Sexual dimorphisms of dopaminergic neurons in rat substantia nigra].

There are sex differences in some brain areas in mammalians. Parkinson's disease (PD), caused by the mesencephalic substantia nigra (SN) dopaminergic neuronal loss, displays sexual difference, i.e., the incidence is higher and the symptoms are more intense in males than that in females. However, it has not been known whether sexual dimorphisms exist in the SN. Sixty adult Sprague-Dawley rats were randomly divided into 5 groups: (1) Female intact group (F-INT group); (2) Male intact group (M-INT group); (3) Ovariectomized group (OVX group); (4) Castration group (CAST group); (5) Ovariectomized + estrogen-replaced group (OVX-E(2) group): The rats received sequentially physiological dose of estrogen for 3 d from the 7th day after ovariectomization. P50 auditory evoked potential (P50) was recorded for 14 d from electrodes inserted in the rat right SN in quiet and awake state. After recording, the brain tissues were dissected and the tyrosine hydroxylase (TH)-expressing neurons in the compact zone of the SN were counted using immunohistochemical method. The results showed that the number of TH-positive (TH(+)) cells in the SN of normal male animals was less than that in normal female rats (P<0.05), and the T/C ratio of P50 in normal males was significantly less than that in normal females (P<0.01), indicating that there exists sexual difference in function and structure in the SN. No differences in the T/C ratio of P50 or the number of TH(+) cells were found between M-INT and CAST groups. The T/C ratio of P50 and the number of TH(+) cells in the SN in OVX group were reduced significantly compared with those in F-INT group (P<0.01). There was no significant difference in the T/C ratio of P50 and the number of TH(+) cells in the SN between OVX- E(2) and F-INT groups 15-20 d after estrogen replacement, suggesting that estrogen can promote the survival and functional recovery of dopaminergic neurons in the SN. The results suggest that there exist sex-specific differences in the dopaminergic neurons in the SN structurally and functionally. The difference of estrogen level in cerebra between male and female animals may account for the sexual differences. Endogenous estrogen plays an important role in maintaining the integrity and modulating the functional activity of dopamine system in the SN.