PAIP1 binds to pre-mRNA and regulates alternative splicing of cancer pathway genes including VEGFA.

BACKGROUND: Poly (A) binding protein interacting protein 1 (PAIP1) has been shown to causally contribute to the development and progression of cancer. However, the mechanisms of the PAIP1 regulation in tumor cells remain poorly understood. RESULTS: Here, we used a recently developed UV cross-linking and RNA immunoprecipitation method (iRIP-seq) to map the direct and indirect interaction sites between PAIP1 and RNA on a transcriptome-wide level in HeLa cells. We found that PAIP1 not only binds to 3'UTRs, but also to pre-mRNAs/mRNAs with a strong bias towards the coding region and intron. PAIP1 binding sites are enriched in splicing enhancer consensus GA-rich motifs. RNA-seq analysis revealed that PAIP1 selectively modulates the alternative splicing of genes in some cancer hallmarks including cell migration, the mTOR signaling pathway and the HIF-1 signaling pathway. PAIP1-regulated alternative splicing events were strongly associated with PAIP1 binding, demonstrating that the binding may promote selection of the nearby splice sites. Deletion of a PAIP1 binding site containing seven repeats of GA motif reduced the PAIP1-mediated suppression of the exon 6 inclusion in a VEGFA mRNA isoform. Proteomic analysis of the PAIP1-interacted proteins revealed the enrichment of the spliceosome components and splicing factors. CONCLUSIONS: These findings suggest that PAIP1 is both a polyadenylation and alternative splicing regulator, that may play a large role in RNA processing via its role in alternative splicing regulation.

Expression of Ubiquitin-specific protease 7 in oral squamous cell carcinoma promotes tumor cell proliferation and invasion.

Oral Squamous Cell Carcinoma (OSCC) is the most common malignant cancer affecting oral cavity. Recent studies have demonstrated that Ubiquitin-specific protease 7 (USP7) was upregulated in several types of cancers. USP7 expression was associated with various proto-oncogenes and tumor suppressor genes. However, USP7 expression level and its functional role in OSCC is unclear. In the current study, we showed that USP7 expression in OSCC tissues was generally upregulated compared to normal adjacent tissues by using IHC. Furthermore, statistical analysis uncovered that USP7 expression was positively correlated with Ki-67, MMP2, VEGF in OSCC tissues. Importantly, high USP7 expression was significantly correlated with lymph node metastasis and histological differentiation in OSCC patients. So, our hypothesis is that USP7 plays a tumor-promoting role in OSCC. Knocking down of USP7 in tumor cells not only suppressed HSC3 cells proliferation, migration and invasion, but also promoted cell apoptosis. Moreover, USP7 siRNA blocked the activation of Akt/ERK signaling pathway. In conclusion, data presented here suggests that USP7 promotes the progression of OSCC. USP7 may be used as a new therapeutic target for OSCC diagnosis and treatment.

Cinnamic Acid (CINN) Induces Apoptosis and Proliferation in Human Nasopharyngeal Carcinoma Cells.

BACKGROUND/AIMS: CINN is the main ingredient of the traditional Chinese medicine cinnamon. The purpose of the present study was to investigate the effects of CINN on the proliferation and apoptosis of NPC cells and to elucidate the underlying molecular mechanisms. MATERIALS AND METHODS: CNE2 human NPC cells were treated with various CINN concentrations. The effects of CINN on the proliferation and apoptosis of CNE2 NPC cells were examined using the MTT assay and flow cytometric analysis. Additionally, western blotting was performed to analyze the expression of a number of cell cycle- and apoptosis-related proteins. RESULTS: The proliferation of CNE2 cells was significantly inhibited after treatment with different CINN concentrations for various lengths of time. The inhibitory effect of CINN was concentration-and time-dependent. Flow cytometric analysis showed that 2 mmol/L CINN displayed a significant apoptosis-inducing effect. The western blot analysis results showed that KLF6, Fas-L, Bax, P53 and caspase-3 protein expression was drastically increased in the CNE2 cells after treatment with 2 mmol/L CINN, whereas Bcl-2 and cyclin D1 protein expression was markedly reduced. CONCLUSION: CINN inhibits the proliferation and induces the apoptosis of CNE2 cells. Therefore, CINN possesses a potential anti-tumor effect.

The Effect of Hippocampal Cognitive Impairment and XIAP on Glucose and Lipids Metabolism in Rats.

BACKGROUND/AIMS: To investigate the effect of cognitive impairment and X-linked inhibitor of apoptosis protein (XIAP) on glucolipid metabolism. MATERIALS AND METHODS: ß-amyloid (Aß 1-42) was injected into the hippocampus of rats to establish a cognitive impairment model. Trans-activator of transcription (TAT)-XIAP fusion protein (the TAT-XIAP group), PBS (the model group), or XIAP antisense oligonucleotides (the ASODN group) was injected into the lateral ventricles of the rats to increase and decrease the activity of XIAP in the hippocampus. To determine the level of blood glucose and lipids, adenosine monophosphate-activated protein kinase (AMPK) expression of liver and hipppocamual neuronal apoptosis. RESULTS: The levels of FPG, TG, TC and LDL were significantly higher in the TAT-XIAP group, the model group and the ASODN group than in the blank group (P < 0.05); however, the HDL level showed no significant change in all groups of rats. The apoptosis indexes of the rat hippocampal CA1 neuron were 68.44 ± 4.31%, 13.21 ± 2.30%, 56.68 ± 4.771%, and 87.51 ± 6.63% in the model group, the blank group, the TAT-XIAP group and the ASODN group, respectively. Gastrointestinal motility was less frequent (per time unit) in the model group, the ASODN group and the TAT-XIAP group than in the blank group. Compared with the model group, gastrointestinal motility was significantly less frequent in the ASODN group and was significantly more frequent in the TAT-XIAP group. Compared with the blank group, the model group had a significantly lower gastric emptying rate and intestinal propulsive rate. Compared with the model group, the gastric emptying rate and intestinal propulsive rate were significantly lower in the ASODN group and were significantly higher in the TAT-XIAP group. Compared with the blank group, the expressions of AMPK mRNA, and AMPK protein were significantly reduced in the model group, the TAT-XIAP group, and the ASODN group. AMPK expression was significantly increased in the TAT-XIAP group and was significantly decreased in the ASODN group than in the model group. CONCLUSION: Cognitive impairment and hippocampal neuron apoptosis can cause glucose and lipids metabolic abnormalities, possibly by regulating gastrointestinal motility and AMPK expression in the liver. The changes in the function of XIAP, which is an anti-apoptotic protein in the hippocampus, may affect the metabolism of glucose and lipids.

Functionalized Exosomes Promote Neural Differentiation of P19 Cells by Activating the Wnt Signaling Pathway.

BACKGROUND: Global population growth and population aging continue to accelerate, and lead to a further increase in the risk of neurological diseases worldwide. Extracellular vesicles secreted by mesenchymal stem cells carry many proteins, lipids, and genetic material that mediate cell-to-cell communication and improve therapeutic outcomes for neurological disorders. Stem cells from human exfoliated deciduous teeth are considered a suitable cell source for tissue regeneration, which exerts therapeutic effects via the secretion of exosomes. METHODS: This study was performed to assess the effect of functionalized exosomes on neural differentiation of embryonic carcinoma cell line P19. We stimulated stem cells from human exfoliated deciduous teeth with the glycogen synthase kinase-3ß inhibitor TWS119 and then extracted its exosomes. P19 cells were induced to differentiate using functionalized exosomes, and the biological functions and involved signaling pathways of differentially expressed genes were analyzed by RNA-sequencing. Immunofluorescence techniques detected neuronal specific markers. RESULTS: It was found that TWS119 activated the Wnt signaling pathway in stem cells from human exfoliated deciduous teeth. RNA-sequencing showed that upregulated differentially expressed genes in the functionalized exosome-treated group were responsible for cell differentiation, neurofilament, and structural constituent of the synapse. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that the functionalized exosome-treated group activated the Wnt signaling pathway. Immunofluorescence showed that functionalized exosomes induced neurite outgrowth in P19 cells. CONCLUSION: Our results demonstrated that functionalized exosomes promoted neural differentiation of P19 cells by activating the Wnt signaling pathway.

Implantation with SHED sheet induced with homogenate protein of spinal cord promotes functional recovery from spinal cord injury in rats.

Introduction: After spinal cord injury (SCI) occurs, the lesion is in a growth inhibitory microenvironment that severely hinders neural regeneration. In this microenvironment, inhibitory factors are predominant and factors that promote nerve regeneration are few. Improving neurotrophic factors in the microenvironment is the key to treating SCI. Methods: Based on cell sheet technology, we designed a bioactive material with a spinal cord-like structure -SHED sheet induced with homogenate protein of spinal cord (hp-SHED sheet). Hp-SHED sheet was implanted into the spinal cord lesion for treating SCI rats with SHED suspensions as a control to investigate the effects on nerve regeneration. Results: Hp-SHED sheet revealed a highly porous three-dimensional inner structure, which facilitates nerve cell attachment and migration. Hp-SHED sheet in vivo restored sensory and motor functions in SCI rats by promoting nerve regeneration, axonal remyelination, and inhibiting glial scarring. Discussion: Hp-SHED sheet maximally mimics the microenvironment of the natural spinal cord and facilitate cell survival and differentiation. Hp-SHED sheet could release more neurotrophins and the sustained action of neurotrophins improves the pathological microenvironment, which effectively promotes nerve regeneration, axonal extension, and inhibits glial scarring, thereby promoting the in situ centralis neuroplasticity. Hp-SHED sheet therapy is a promising strategy for effective treatment of SCI based on neurotrophins delivery.

Bioactive Spinal Cord Scaffold Releasing Neurotrophic Exosomes to Promote In Situ Centralis Neuroplasticity.

Spinal cord injury (SCI), one of the most serious injuries of the central nervous system, causes physical functional dysfunction and even paralysis in millions of patients. As a matter of necessity, redressing the neuroleptic pathologic microenvironment to a neurotrophic microenvironment is essential in order to alleviate this dilemma and facilitate the recovery of the spinal cord. Herein, based on cell-sheet technology, two functional cell types─uninduced and neural-induced stem cells from human exfoliated deciduous teeth─were formed into a composite membrane that subsequently self-assembled to form a bioactive scaffold with a spinal-cord-like structure, called a spinal cord assembly (SCA). In a stable extracellular matrix microenvironment, SCA continuously released SCA-derived exosomes containing various neurotrophic factors, which effectively promoted neuronal regeneration, axonal extension, and angiogenesis and inhibited glial scar generation in a rat model of SCI. Neurotrophic exosomes significantly improved the pathological microenvironment and promoted in situ centralis neuroplasticity, ultimately eliciting a strong repair effect in this model. SCA therapy is a promising strategy for the effective treatment of SCI based on neurotrophic exosome delivery.

Proteome Dynamics Analysis Reveals the Potential Mechanisms of Salinity and Drought Response during Seed Germination and Seedling Growth in Tamarix hispida.

Understanding the molecular mechanisms of seed germination and seedling growth is vital for mining functional genes for the improvement of plant drought in a desert. Tamarix hispida is extremely resistant to drought and soil salinity perennial shrubs or trees. This study was the first to investigate the protein abundance profile of the transition process during the processes of T. hispida seed germination and seedling growth using label-free proteomics approaches. Our data suggested that asynchronous regulation of transcriptomics and proteomics occurs upon short-term seed germination and seedling growth of T. hispida. Enrichment analysis revealed that the main differentially abundant proteins had significant enrichment in stimulus response, biosynthesis, and metabolism. Two delta-1-pyrroline-5-carboxylate synthetases (P5CS), one Ycf3-interacting protein (Y3IP), one low-temperature-induced 65 kDa protein-like molecule, and four peroxidases (PRX) were involved in both water deprivation and hyperosmotic salinity responses. Through a comparative analysis of transcriptomics and proteomics, we found that proteomics may be better at studying short-term developmental processes. Our results support the existence of several mechanisms that enhance tolerance to salinity and drought stress during seedling growth in T. hispida.

Expression of USP22 and the chromosomal passenger complex is an indicator of malignant progression in oral squamous cell carcinoma.

Oral cancer is a common cancer of the head and neck. Oral squamous cell carcinoma (OSCC) represents almost 90% of the total cases of head and neck cancer. Ubiquitin-specific protease 22 (USP22) is a deubiquitinating hydrolase, and it is highly expressed in various types of cancer, which also typically have a poor prognosis. Aurora-B and Survivin, which belong to the chromosomal passenger complex, are also highly expressed in a number of types of cancer. In the present study, USP22 expression and its associations with Aurora-B and Survivin, and the clinicopathological features in OSCC were explored. USP22 is highly expressed in OSCC. Overexpression of USP22 is associated with lymph node metastasis and histological grade (P<0.01). Additionally, the expression of USP22 was positively associated with Aurora-B (P<0.01), Survivin (P<0.01), and Ki-67 (P<0.01). Furthermore, USP22 small interfering RNA inhibited cell growth and reduced the expression levels of Aurora-B, Survivin and Cyclin B, together with the upregulation of cyclin-dependent kinase inhibitor 1A (p21). These data suggest that USP22, Aurora-B and Survivin promote the OSCC development and may represent novel targets for OSCC diagnosis and treatment in the future.

Aurora Kinase Inhibitors in Head and Neck Cancer.

Aurora kinases are a group of serine/threonine kinases responsible for the regulation of mitosis. In recent years, with the increase in Aurora kinase-related research, the important role of Aurora kinases in tumorigenesis has been gradually recognized. Aurora kinases have been regarded as a new target for cancer therapy, resulting in the development of Aurora kinase inhibitors. The study and application of these small-molecule inhibitors, especially in combination with chemotherapy drugs, represent a new direction in cancer treatment. This paper reviews studies on Aurora kinases from recent years, including studies of their biological function, their relationship with tumor progression, and their inhibitors.

Expression of survivin, MUC2 and MUC5 in colorectal cancer and their association with clinicopathological characteristics.

Survivin is a bifunctional protein that suppresses apoptosis and regulates cell division, and is highly expressed in various cancer types. Mucins are high-molecular-weight, heavily glycosylated proteins. In the present study, the association between survivin, mucin 2 (MUC2) and MUC5 expression, and the clinicopathological features of colorectal cancer (CRC) were investigated. The immunohistochemistry and western blotting results demonstrated that survivin was highly expressed in CRC tissues and rarely expressed in normal colon tissues. Moreover, the overexpression of survivin and MUC5 was strongly associated with lymph node metastasis, poor cellular differentiation, advanced tumor stage and a poor prognosis in CRC. By contrast, low expression of MUC2 was significantly associated with lymph node metastasis, poor cellular differentiation and an advanced tumor stage in CRC. The results of the present study suggest that survivin, MUC2 and MUC5 levels may be associated with tumor progression and could be used to aid the early diagnosis and clinical characterization of CRC.

PARP6 acts as a tumor suppressor via downregulating Survivin expression in colorectal cancer.

Poly (ADP-ribose) polymerases (PARPs) are enzymes that transfer ADP-ribose groups to target proteins and are involved in a variety of biological processes. PARP6 is a novel member, and our previous findings suggest that PARP6 may act as a tumor suppressor via suppressing cell cycle progression. However, it is still unclear that PARP6 function besides growth suppression in colorectal cancer (CRC). In this study, we examined tumor suppressive roles of PAPR6 in CRC cells both in vitro and in vivo. We found that PARP6 inhibited colony formation, invasion and migration as well as cell proliferation. Moreover, ectopic overexpression of PARP6 decreased Survivin expression, which acts as an oncogene and is involved in apoptosis and mitosis. We confirmed the inverse correlation between PARP6 and Survivin expression in CRC cases by immunohistochemistry. Importantly, CRC cases with downregulation of PARP6 and upregulation of Survivin showed poor prognosis. In summary, PARP6 acts as a tumor suppressor via downregulating Survivin expression in CRC. PARP6 can be a novel diagnostic and therapeutic target together with Survivin for CRC.