VPAC2 Receptor Signaling Promotes Growth and Immunosuppression in Pancreatic Cancer.

Pancreatic cancer (PDAC) harbors a complex tumor microenvironment (TME), and crosstalk between cells in the TME can contribute to drug resistance and relapse. Vasoactive intestinal peptide (VIP) is overexpressed in PDAC, and VIP receptors expressed on T cells are a targetable pathway that sensitizes PDAC to immunotherapy. In this study, we showed that pancreatic cancer cells engage in autocrine VIP signaling through VIP receptor 2 (VPAC2). High co-expression of VIP with VPAC2 correlated with reduced relapse-free survival in PDAC patients. VPAC2 activation in PDAC cells upregulated piwi-like RNA-mediated gene silencing 2 (Piwil2), which stimulated cancer cell clonogenic growth. In addition, VPAC2 signaling increased expression of TGF-ß1 to inhibit T cell function. Loss of VPAC2 on PDAC cells led to reduced tumor growth and increased sensitivity to anti-PD1 immunotherapy in mouse models of PDAC. Overall, these findings expand our understanding of the role of VIP/VPAC2 signaling in PDAC and provide the rationale for developing potent VPAC2-specific antagonists for treating PDAC patients.

The Role of Bioactives in Inflammation.

As a physiological defense mechanism, inflammation is a complex response to harmful stimuli [...].

Chrysophanol Suppresses Cell Growth via mTOR/PPAR-α Regulation and ROS Accumulation in Cultured Human Tongue Squamous Carcinoma SAS Cells.

Oral cancer, a type of head and neck cancer, can pose a significant risk of death unless diagnosed and treated early. Alternative treatments are urgently needed owing to the high mortality rate, limitations of conventional treatments, and many complications. The anthraquinone compound chrysophanol acts as a tumor suppressor on some types of cancer cells. To date, it has not been clarified how chrysophanol affects human tongue squamous carcinoma. This study was aimed to examine the effects of chrysophanol on oral cancer treatment. The results show that chrysophanol caused cell death, reduced the expression of the mammalian target of rapamycin (mTOR)/peroxisome proliferator-activated receptor-alpha (PPAR-α), and increased reactive oxygen species (ROS) production. We also used two ion chelators, deferoxamine (DFO) and liproxstatin-1 (Lipro), to further determine whether chrysophanol inhibits cell growth and regulates mTOR/PPAR-α expression and ROS production, both of which are involved in iron homeostasis. The results show that DFO and Lipro reversed the increase in cell death, downregulation of mTOR/PPAR-α, and decrease in ROS accumulation. In conclusion, chrysophanol inhibits the growth of oral squamous cell carcinoma cells by modulating mTOR/PPAR-α and by causing ROS accumulation.

Interleukin-6 and Interleukin-8 Regulate STAT3 Activation Migration/Invasion and EMT in Chrysophanol-Treated Oral Cancer Cell Lines.

The tumor microenvironment plays a critical role in the control of metastasis. The epithelial-mesenchymal transition (EMT) is strongly associated with tumor metastasis, and consists of several protein markers, including E-cadherin and vimentin. We discovered that chrysophanol causes oral cancer cell apoptosis and the inhibition of migration/invasion and EMT. However, the detailed mechanisms of chrysophanol and its role in oral cancer with respect to the tumor microenvironment remain unknown. In the clinic, proinflammatory cytokines, such as IL-6 and IL-8, exhibit a higher expression in patients with oral cancer. However, the effect of chrysophanol on the production of IL-6 and IL-8 is unknown. We evaluated the expression of IL-6 and IL-8 in human SAS and FaDu oral cancer cell lines in the presence or absence of chrysophanol. The migration and invasion abilities were also determined using a Boyden chamber assay. Our results showed that treatment with chrysophanol significantly decreased the expression of IL-6 and IL-8, as well as the invasion ability of oral cancer cells. Moreover, chrysophanol also attenuated the EMT by increasing the expression of E-cadherin and reducing the expression of vimentin. Mechanistically, chrysophanol inhibited IL-6- and IL-8-induced invasion and STAT3 phosphorylation. IL-6 and IL-8 promote EMT and cell invasion, which is potentially related to the STAT3 signaling pathway in oral cancer. These findings provide insight into new aspects of chrysophanol activity and may contribute to the development of new therapeutic strategies for oral cancer.

Role of Chrysophanol in Epithelial-Mesenchymal Transition in Oral Cancer Cell Lines via a Wnt-3-Dependent Pathway.

Oral cancer belongs to the group of head and neck cancers. If not diagnosed or treated early, it can be life threatening. Epithelial-mesenchymal transition (EMT) plays an important role in tumor formation and progression. An increase in the presence of the EMT phenotype causes tumor cell proliferation, migration, invasion, and poor prognosis. Therefore, attenuating carcinogenesis via EMT inhibition is a good strategy. Herein, we will determine the pharmacological effects of chrysophanol on the EMT in FaDu cells. To analyze EMT, we detected the expression EMT markers, including α-SMA, ß-catenin, vimentin, N-cadherin, E-cadherin, phospho-GSK-3ß, and nuclear translocations of p65 and ß-catenin by western blotting. Additionally, accumulating evidence indicates that reactive oxygen species (ROS) mediate EMT. Our results showed that the level of ROS was significantly increased after chrysophanol treatment. We further speculated that chrysophanol-mediated EMT and metastasis are involved in the Wnt-3-dependent signaling pathway. The inhibition of the EMT phenotype and metastasis and accumulation of ROS caused by chrysophanol was reversed by treatment with the Wnt-3 agonist Bml 284. Therefore, our findings indicated that chrysophanol altered EMT formation, ROS accumulation, and metastasis via the Wnt-3-dependent signaling pathway.

Chrysophanol Regulates Cell Death, Metastasis, and Reactive Oxygen Species Production in Oral Cancer Cell Lines.

BACKGROUND: Oral cancer belongs to the class of head and neck cancers and can be life threatening if not diagnosed and treated early. Activation of cell death via apoptosis or reactive oxygen species (ROS) accumulation and inhibition of cell cycle progression, migration, and epithelial-to-mesenchymal transition (EMT) may be a good strategy to arrest the development of oral cancer. In this study, we analyzed the possible action of chrysophanol isolated from the rhizomes of Rheum palmatum on the oral cancer cell lines FaDu (human pharynx squamous cell carcinoma) and SAS (human tongue squamous carcinoma) by investigating whether chrysophanol could influence cell death. METHOD: Cell viability was measured by using the MTT assay. For the detection of apoptosis, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and subG1 population analysis were used. We also examined cell cycle progression and ROS levels by flow cytometry. Additionally, the expression of p53, p21, procaspase 3, cyclin D1, CDK4, cdc2, CDK2, E-cadherin, vimentin, and PCNA was evaluated by western blotting. CONCLUSION: Chrysophanol has an anticancer effect on FaDu and SAS cell lines. There is an increase in subG1 accumulation, ROS production, and cell cycle G1 arrest after treatment with chrysophanol. On the other hand, chrysophanol inhibited cell migration/metastasis and EMT. We proposed that chrysophanol may be a good candidate compound on oral cancer treatment in the further.

Wwox deficiency leads to neurodevelopmental and degenerative neuropathies and glycogen synthase kinase 3ß-mediated epileptic seizure activity in mice.

Human WWOX gene resides in the chromosomal common fragile site FRA16D and encodes a tumor suppressor WW domain-containing oxidoreductase. Loss-of-function mutations in both alleles of WWOX gene lead to autosomal recessive abnormalities in pediatric patients from consanguineous families, including microcephaly, cerebellar ataxia with epilepsy, mental retardation, retinal degeneration, developmental delay and early death. Here, we report that targeted disruption of Wwox gene in mice causes neurodevelopmental disorders, encompassing abnormal neuronal differentiation and migration in the brain. Cerebral malformations, such as microcephaly and incomplete separation of the hemispheres by a partial interhemispheric fissure, neuronal disorganization and heterotopia, and defective cerebellar midline fusion are observed in Wwox-/- mice. Degenerative alterations including severe hypomyelination in the central nervous system, optic nerve atrophy, Purkinje cell loss and granular cell apoptosis in the cerebellum, and peripheral nerve demyelination due to Schwann cell apoptosis correspond to reduced amplitudes and a latency prolongation of transcranial motor evoked potentials, motor deficits and gait ataxia in Wwox-/- mice. Wwox gene ablation leads to the occurrence of spontaneous epilepsy and increased susceptibility to pilocarpine- and pentylenetetrazol (PTZ)-induced seizures in preweaning mice. We determined that a significantly increased activation of glycogen synthase kinase 3ß (GSK3ß) occurs in Wwox-/- mouse cerebral cortex, hippocampus and cerebellum. Inhibition of GSK3ß by lithium ion significantly abolishes the onset of PTZ-induced seizure in Wwox-/- mice. Together, our findings reveal that the neurodevelopmental and neurodegenerative deficits in Wwox knockout mice strikingly recapitulate the key features of human neuropathies, and that targeting GSK3ß with lithium ion ameliorates epilepsy.