Lijie Ma

Differential regulation of β-arrestin 1 and β-arrestin 2 gene expression in rat brain by morphine

Abstract β-Arrestins are a family of regulatory and scaffold proteins functioning in signal transduction of G protein-coupled receptors including opioid receptors. Upon agonist stimulation, β-arrestins bind to opioid receptors phosphorylated by G protein-coupled receptor kinases and promote receptor internalization and desensitization. Studies indicated that β-arrestins are required in the development of morphine tolerance in mice. In the current study, we investigated the potential regulatory effects of morphine administration on β-arrestin 1 and β-arrestin 2 mRNA levels in different brain regions in rat using in situ hybridization method. Our results showed that the acute morphine administration (10 mg/kg) resulted in approximately 30% reduction in both β-arrestin 1 and β-arrestin 2 mRNA levels in hippocampus while the chronic morphine treatment (10 mg/kg, b.i.d., for 9 days) caused no significant change in level of either β-arrestin mRNA. In locus coeruleus, both acute and chronic morphine treatments resulted in significant decreases (over 50%) in β-arrestin 1 mRNA level but failed to induce any change in the level of β-arrestin 2 gene expression. The acute morphine administration had no significant effect on β-arrestin 1 or β-arrestin 2 mRNA level in periaqueductal gray and cerebral cortex. However, after chronic morphine treatment, β-arrestin 2 mRNA level decreased by 40% in periaqueductal gray and increased by 25% in cerebral cortex, in strong contrast to the unchanged β-arrestin 1 mRNA level in these two brain regions. Furthermore, spontaneous or naloxone-precipitated withdrawal of morphine that did not affect the level of β-arrestin 1 mRNA resulted in an aberrant increase (100% over control) in β-arrestin 2 mRNA level in hippocampus. Our results thus demonstrated for the first time that opiate administration regulates level of β-arrestin mRNAs in brain and the expression of β-arrestin 1 and β-arrestin 2 subtypes is differentially regulated in locus coeruleus, periaqueductal gray, and cerebral cortex by morphine. These data suggest that β-arrestin 1 and β-arrestin 2 may play different roles in the development of opioid tolerance and dependence.

CD86+/CD206+, Diametrically Polarized Tumor-Associated Macrophages, Predict Hepatocellular Carcinoma Patient Prognosis

Tumor-associated macrophages (TAMs), the most abundant infiltrating immune cells in tumor microenvironment, have distinct functions in hepatocellular carcinoma (HCC) progression. CD68+ TAMs represent multiple polarized immune cells mainly containing CD86+ antitumoral M1 macrophages and CD206+ protumoral M2 macrophages. TAMs expression and density were assessed by immunohistochemical staining of CD68, CD86, and CD206 in tissue microarrays from 253 HCC patients. Clinicopathologic features and prognostic value of these markers were evaluated. We found that CD68+ TAMs were not associated with clinicopathologic characteristics and prognosis in HCC. Low presence of CD86+ TAMs and high presence of CD206+ TAMs were markedly correlated with aggressive tumor phenotypes, such as multiple tumor number and advanced tumor-node-metastasis (TNM) stage; and were associated with poor overall survival (OS) (p = 0.027 and p = 0.024, respectively) and increased time to recurrence (TTR) (p = 0.037 and p = 0.031, respectively). In addition, combined analysis of CD86 and CD206 provided a better indicator for OS (p = 0.011) and TTR (p = 0.024) in HCC than individual analysis of CD86 and CD206. Moreover, CD86+/CD206+ TAMs predictive model also had significant prognosis value in α-fetoprotein (AFP)-negative patients (OS: p = 0.002, TTR: p = 0.005). Thus, these results suggest that combined analysis of immune biomarkers CD86 and CD206 could be a promising HCC prognostic biomarker.

Protein tyrosine phosphatase PTP4A1 promotes proliferation and epithelial-mesenchymal transition in intrahepatic cholangiocarcinoma via the PI3K/AKT pathway

The protein tyrosine phosphatase PTP4A1 is a key molecule that activates tyrosine phosphorylation, which is important for cancer progression and metastasis. However, the clinical implications and biological function of PTP4A1 in intrahepatic cholangiocarcinoma (ICC) remains unknown. Here, we showed that PTP4A1 was frequently overexpressed in ICC versus adjacent non-tumor tissues. This overexpression significantly correlated with aggressive tumor characteristics like the presence of lymph node metastasis and advanced tumor stages. Survival analysis further indicated that high PTP4A1 expression was significantly and independently associated with worse survival and increased recurrence in ICC patients. Moreover, through forced overexpression and knock-down of PTPT4A1, we demonstrated that PTP4A1 could significantly promote ICC cells proliferation, colony formation, migration, and invasion in vitro, and markedly enhance tumor progression in vivo. Mechanistically, PTP4A1 was involved in PI3K/AKT signaling and its downstream molecules, such as phosphorylation level of GSK3β and up-regulation of CyclinD1, in ICC cells to promote proliferation. Importantly, PTP4A1 induced ICC cells invasion was through activating PI3K/AKT signaling controlled epithelial-mesenchymal transition (EMT) process by up-regulating Zeb1 and Snail. Thus, PTP4A1 may serve as a potential oncogene that was a valuable prognostic biomarker and therapeutic target for ICC.

CAPS1 Negatively Regulates Hepatocellular Carcinoma Development through Alteration of Exocytosis-Associated Tumor Microenvironment

The calcium-dependent activator protein for secretion 1 (CAPS1) regulates exocytosis of dense-core vesicles (DCVs) in neurons and neuroendocrine cells. The role of CAPS1 in cancer biology remains unknown. The purpose of this study was to investigate the role of CAPS1 in hepatocellular carcinoma (HCC). We determined the levels of CAPS1 in eight hepatoma cell lines and 141 HCC specimens. We evaluated the prognostic value of CAPS1 expression and its association with clinical parameters. We investigated the biological consequences of CAPS1 overexpression in two hepatoma cell lines in vitro and in vivo. The results showed that loss of CAPS1 expression in HCC tissues was markedly correlated with aggressive tumor phenotypes, such as high-grade tumor node metastasis (TNM) stage (p = 0.003) and absence of tumor encapsulation (p = 0.016), and was associated with poor overall survival (p = 0.008) and high recurrence (p = 0.015). CAPS1 overexpression inhibited cell proliferation and migration by changing the exocytosis-associated tumor microenvironment in hepatoma cells in vitro. The in vivo study showed that CAPS1 overexpression inhibited xenograft tumor growth. Together, these results identified a previously unrecognized tumor suppressor role for CAPS1 in HCC development.

CCL15 recruits suppressive monocytes to facilitate immune escape and disease progression in hepatocellular carcinoma

Chemokines play a key role in orchestrating the recruitment and positioning of myeloid cells within the tumor microenvironment. However, the tropism regulation and functions of these cells in hepatocellular carcinoma (HCC) are not completely understood. Herein, by scrutinizing the expression of all chemokines in HCC cell lines and tissues, we found that CCL15 was the most abundantly expressed chemokine in human HCC. Further analyses showed that CCL15 expression was regulated by genetic, epigenetic, and microenvironmental factors, and negatively correlated with patient clinical outcome. In addition to promoting tumor invasion in an autocrine manner, CCL15 specifically recruited CCR1+ cells toward HCC invasive margin, approximately 80% of which were CD14+ monocytes. Clinically, a high density of marginal CCR1+CD14+ monocytes positively correlated with CCL15 expression and was an independent index for dismal survival. Functionally, these tumor‐educated monocytes directly accelerated tumor invasion and metastasis through bursting various pro‐tumor factors and activating signal transducer and activator of transcription 1/3, extracellular signal‐regulated kinase 1/2, and v‐akt murine thymoma viral oncogene homolog signaling in HCC cells. Meanwhile, tumor‐derived CCR1+CD14+ monocytes expressed significantly higher levels of programmed cell death‐ligand 1, B7‐H3, and T‐cell immunoglobulin domain and mucin domain‐3 that may lead to immune suppression. Transcriptome sequencing confirmed that tumor‐infiltrating CCR1+CD14+ monocytes were reprogrammed to upregulate immune checkpoints, immune tolerogenic metabolic enzymes (indoleamine and arginase), inflammatory/pro‐angiogenic cytokines, matrix remodeling proteases, and inflammatory chemokines. Orthotopic animal models confirmed that CCL15‐CCR1 axis forested an inflammatory microenvironment enriched with CCR1+ monocytes and led to increased metastatic potential of HCC cells. Conclusion: A complex tumor‐promoting inflammatory microenvironment was shaped by CCL15‐CCR1 axis in human HCC. Blockade of CCL15‐CCR1 axis in HCC could be an effective anticancer therapy.

FXR Acts as a Metastasis Suppressor in Intrahepatic Cholangiocarcinoma by Inhibiting IL-6-Induced Epithelial-Mesenchymal Transition

Background/Aims: Intrahepatic cholangiocarcinoma (ICC) is a complicated condition, with difficult diagnosis and poor prognosis. The expression and clinical significance of the farnesoid X receptor (FXR), an endogenous receptor of bile acids, in ICC is not well understood. Methods: Western blotting and immunochemical analyses were used to determine the levels of FXR in 4 cholangiocarcinoma cell lines, a human intrahepatic biliary epithelial cell line (HIBEpic) and 322 ICC specimens, respectively, while quantitative reverse transcription polymerase chain reaction was used to detect the mRNA levels of FXR in cholangiocarcinoma cell lines. We evaluated the prognostic value of FXR expression and its association with clinical parameters. We determined the biological significance of FXR in ICC cell lines by agonist-mediated activation and lentivirus-mediated silence. IL-6 expression was tested by an enzyme-linked immunosorbent assay and flow cytometry. In vitro, cell proliferation was examined by Cell Counting Kit-8, migration and invasion were examined by wound healing and transwell assays; in vivo, tumor migration and invasion were explored in NOD-SCID mice. Results: FXR was downregulated in ICC cell lines and clinical ICC specimens. Loss of FXR was markedly correlated with aggressive tumor phenotypes and poor prognosis in patients with ICC. Moreover, FXR expression also had significant prognostic value in carbohydrate antigen 19-9 (CA19-9) negative patients. The expression of FXR was negatively correlated with IL-6 levels in clinical ICC tissues. FXR inhibited the proliferation, migration, invasion and epithelial mesenchymal transition (EMT) of ICC cells via suppression of IL-6 in vitro. Obeticholic acid, an agonist of FXR, inhibited IL-6 production, tumor growth and lung metastasis of ICC in vivo. Conclusions: FXR could be a promising ICC prognostic biomarker, especially in CA19-9 negative patients with ICC. FXR inhibits the tumor growth and metastasis of ICC via IL-6 suppression.

Telomere length variation in tumor cells and cancer‐associated fibroblasts: potential biomarker for hepatocellular carcinoma

The role of telomere dysfunction and aberrant telomerase activities in hepatocellular carcinoma (HCC) has been overlooked for many years. This study aimed to delineate the variation and prognostic value of telomere length in HCC. Telomere‐specific fluorescence in situ hybridization (FISH) and qPCR were used to evaluate telomere length in HCC cell lines, tumor tissues, and isolated non‐tumor cells within the tumor. Significant telomere attrition was found in tumor cells and cancer‐associated fibroblasts (CAFs) compared to their normal counterparts, but not in intratumor leukocytes or bile duct epithelial cells. Clinical relevance and prognostic value of telomere length were investigated on tissue microarrays of 257 surgically treated HCC patients. Reduced intensity of telomere signals in tumor cells or CAFs correlated with larger tumor size and the presence of vascular invasion (p < 0.05). Shortened telomeres in tumor cells or CAFs associated with reduced survival and increased recurrence, and were identified as independent prognosticators for HCC patients (p < 0.05). These findings were validated in an independent HCC cohort of 371 HCC patients from The Cancer Genome Atlas (TCGA) database, confirming telomere attrition and its prognostic value in HCC. We also showed that telomerase reverse transcriptase promoter (TERTp) mutation correlated with telomere shortening in HCC. Telomere variation in tumor cells and non‐tumor cells within the tumor microenvironment of HCC was a valuable prognostic biomarker for this fatal malignancy.

FOXP3 Is a HCC suppressor gene and Acts through regulating the TGF-β/Smad2/3 signaling pathway

BackgroundFOXP3 has been discovered to be expressed in tumor cells and participate in the regulation of tumor behavior. Herein, we investigated the clinical relevance and biological significance of FOXP3 expression in human hepatocellular carcinoma (HCC).MethodsExpression profile of FOXP3 was analyzed using real-time RT-PCR, western blotting and immunofluorescence on HCC cell lines, and immunostaing of a tissue microarray containing of 240 primary HCC samples. The potential regulatory roles of FOXP3 were dissected by an integrated approach, combining biochemical assays, analysis of patient survival, genetic manipulation of HCC cell lines, mouse xenograft tumor models and chromatin immunoprecipitation (ChIP) sequencing.ResultsFOXP3 was constitutively expressed in HCC cells with the existence of splice variants (especially exon 3 and 4 deleted, Δ3,4-FOXP3). High expression of FOXP3 significantly correlated with low serum α-fetoprotein (AFP) level, absence of vascular invasion and early TNM stage. Survival analyses revealed that increased FOXP3 expression was significantly associated with better survival and reduced recurrence, and served as an independent prognosticator for HCC patients. Furthermore, FOXP3 could potently suppress the proliferation and invasion of HCC cells in vitro and reduce tumor growth in vivo. However, Δ3,4-FOXP3 showed a significant reduction in the tumor-inhibiting effect. The inhibition of FOXP3 on HCC aggressiveness was acted probably by enhancing the TGF-β/Smad2/3 signaling pathway.ConclusionOur findings suggest that FOXP3 suppresses tumor progression in HCC via TGF-β/Smad2/3 signaling pathway, highlighting the role of FOXP3 as a prognostic factor and novel target for an optimal therapy against this fatal malignancy.