LGR4 and LGR6 are differentially expressed and of putative tumor biological significance in gastric carcinoma

Study on the mechanism of macrophages activated by phosphoesterified rehmanniae polysaccharide on human gastric cancer cells

Gastric cancer(GC)is one of the most common gastrointestinal malignant tumors in the world, requiring the development of novel therapeutic agents with reduced toxicity. Rehmannia polysaccharide (RPS) possesses immunomodulatory and anti-tumor properties, yet its efficacy is suboptimal. To enhance its biological activity, we subjected RPS to molecular modifications, resulting in phosphorylated Rehmannia polysaccharides (P-RPS). Using the mixed phosphate method, we synthesized P-RPS and optimized the synthesis conditions through a combination of single-factor and response surface methodologies. In vitro studies on P-RPS's anti-tumor activity showed no direct influence on the viability of GC cells. However, P-RPS induced the transformation of PMA-activated THP-1 cells into the M1 phenotype. We collected conditioned medium (CM) of THP-1 cells to stimulate gastric cancer cells and CM-P-RPS significantly promoted apoptosis of gastric cancer cells and inhibited cell proliferation, and reduced cell migration. Mechanistically, CM-P-RPS inhibits the Wnt/β-catenin signaling pathway through LGR6, leading to the suppression of tumor growth. Furthermore, P-RPS demonstrated a significant inhibitory effect on tumor growth in vivo, suggesting its potential as a promising therapeutic agent for GC treatment.

The G protein-coupled receptor-related gene signatures for predicting prognosis and immunotherapy response in bladder urothelial carcinoma

Bladder urothelial carcinoma (BLCA) is the most common malignant tumor of the urinary tract with a high lethality rate, and its immunotherapy resistance and tumor recurrence have become a major challenge in its clinical treatment. G Protein-Coupled Receptors (GPRs) are the largest family of receptors on the cell membrane surface, involved in multiple signaling pathways, and are excellent targets for oncology drug action. The transcriptome profile, single cell transcriptome profile, and clinical data of BLCA were extracted and integrated from TCGA and GEO databases, respectively. The GPR-related genes were obtained from GSEA-MSigDB database. The GPR-related gene signatures of 15 genes were constructed by using the methods of least absolute shrinkage and selection operator regression, multifactor Cox model. At the same time, tumor microenvironment (TME)-score signatures were constructed based on the immune microenvironment of BLCA, and GPR-TME-score signature was further constructed. The stability of this model was verified by using the external dataset GSE160693. We constructed risk groups by combining BLCA patient prognostic information, and with the help of BLCA scRNA transcriptome profiling, we explored differences in prognosis, immune scores, cell-cell interactions, tumor mutational burden, immune checkpoints, and response to immunotherapy in each risk group. We found that the GPR-TME-score signature was an independent prognostic factor for BLCA patients. the TME-score was a protective factor for the prognosis of BLCA patients. Among BLCA patients, GPR-high + TME-low risk group had the worst prognosis, while GPR-high + TME-high risk group had the best prognosis, and the latter had better immune score and immunotherapy response. The above differences in immune response among the subgroups may be related to the higher immune cell infiltration in the GPR-high + TME-high group. GPR-related gene signatures and TME are closely related to BLCA prognosis and immunotherapy, and GPR-related gene signature can be a useful tool to assess BLCA prognosis and immunotherapy response.

ERR-activated GPR35 promotes immune infiltration level of macrophages in gastric cancer tissues

Enhancer release and retargeting (ERR) events could activate disease-causing gene promoters for increasing the expression level of oncogenes. Meanwhile, class A orphan GPCRs (oGPCRs) are known as potential biomarkers or drug targets for various cancers, such as gastric cancer (GC). Hence, systemic investigation of ERR events for class A oGPCRs in GC could help to explore biomarkers for GC. In this study, ENCODE and GTEx eQTL data were utilized to define ERR events in GC. Only GPR35 was then detected that could be activated by ERR in GC based on these data and ChIP-seq. Then, activated GPR35 functional in GC cells were explored by flow cytometry, cell-based wound healing assay, Transwell migration assay, and M2 polarization of macrophages assay. Meanwhile, according to TCGA and GEO database, overall survival, immune-related gene expression, and immune cell infiltration level in different GPR35 expressions were calculated. Here, we found ERR event activate GPR35 results in GC cells proliferation and migration, and partly immune cells significance exhaustion (CD8 + T-cells and CD4 + memory T-cells) and/or infiltration (T-cells and macrophage). Meanwhile, high GRP35 level leads to a poor prognosis in GC patients, probably partly due to it promoting the immune infiltration level of macrophages and then inducing polarization of M2 macrophages. Notably, GPR35’s high expression in CTSB+ and CD68 + macrophage could be a genetic indicator for early warning of primary GC. Hence, our findings provide a novel activation approach for oGPCRs, and GPR35 could be determined as a new drugable receptor and early genetic indicator for GC.

Resolution of inflammation: An organizing principle in biology and medicine

The resolution of inflammation has emerged as a critical endogenous process that protects host tissues from prolonged or excessive inflammation that can become chronic. Failure of the resolution of inflammation is a key pathological mechanism that drives the progression of numerous inflammation-driven diseases. Essential polyunsaturated fatty acid (PUFA)-derived autacoid mediators termed 'specialized pro-resolving mediators' (SPMs) regulate endogenous resolution programs by limiting further neutrophil tissue infiltration and stimulating local immune cell (e.g., macrophage)-mediated clearance of apoptotic polymorphonuclear neutrophils, cellular debris, and microbes, as well as counter-regulating eicosanoid/cytokine production. The SPM superfamily encompasses lipoxins, resolvins, protectins, and maresins. Our understanding of the resolution phase of acute inflammation has grown exponentially in the past three decades with the discovery of novel pro-resolving lipid mediators, their pro-efferocytosis mechanisms, and their receptors. Technological advancement has further facilitated lipid mediator metabolipidomic based profiling of healthy and diseased human tissues, highlighting the extraordinary therapeutic potential of SPMs across a broad array of inflammatory diseases including cancer. As current front-line cancer therapies such as surgery, chemotherapy, and radiation may induce various unwanted side effects such as robust pro-inflammatory and pro-tumorigenic host responses, characterizing SPMs and their receptors as novel therapeutic targets may have important implications as a new direction for host-targeted cancer therapy. Here, we discuss the origins of inflammation resolution, key discoveries and the failure of resolution mechanisms in diseases with an emphasis on cancer, and future directions focused on novel therapeutic applications for this exciting and rapidly expanding field.

The Role of LGR4 (GPR48) in Normal and Cancer Processes

Leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) is a receptor that belongs to the superfamily of G protein-coupled receptors that can be activated by R-spondins (RSPOs), Norrin, circLGR4, and the ligand of the receptor activator of nuclear factor kappa-B (RANKL) ligands to regulate signaling pathways in normal and pathological processes. LGR4 is widely expressed in different tissues where it has multiple functions such as tissue development and maintenance. LGR4 mainly acts through the Wnt/β-catenin pathway to regulate proliferation, survival, and differentiation. In cancer, LGR4 participates in tumor progression, invasion, and metastasis. Furthermore, recent evidence reveals that LGR4 is essential for the regulation of the cancer stem cell population by controlling self-renewal and regulating stem cell properties. This review summarizes the function of LGR4 and its ligands in normal and malignant processes.

LGR4 overexpression is associated with clinical parameters and poor prognosis of serous ovarian cancer

OBJECTIVE

LGR4 expression in serous ovarian cancer paraffin-embedded tissues and fresh tissues were investigated, and its expression associated with clinicopathological parameters and prognosis in serous ovarian cancer was explored.

METHODS

From Dec, 2009 to Jan, 2020, 122 paraffin-embedded serous ovarian cancer patients and 41 paired paratumor tissues who were both diagnosed and operated at the memorial hospital of Sun Yat-sen University and Integrated Hospital of Traditional Chinese Medicine, Southern Medical University were selected in this research, respectively, and all of these tissues were performed by immunohistochemistry (IHC) with a polyclonal antibody for LGR4. Meanwhile, from Aug, 2013 to Mar, 2019, 15 cases of serous ovarian cancer fresh tissues and 15 cases of paratumor fresh tissues who were operated at Integrated Hospital of Traditional Chinese Medicine, Southern Medical University were performed with Quantitative Real-time PCR to detect the mRNA expression of LGR4, respectively.

RESULTS

LGR4 expression was much higher both in paraffin-embedded and fresh cancer tissues than that in paratumor tissues, respectively, and its expression was associated with recurrence free survival and overall survival in serous ovarian cancer patients. Moreover, in a multivariate model LGR4 was an indeed independent predictor of poor survival in serous ovarian cancer patients.

CONCLUSION

LGR4 is upregulated in serous ovarian cancer, and LGR4 is an indeed useful independent prognostic predictor in serous ovarian cancer, and it may provide important clinical value of serous ovarian cancer.

LGR6 is a potential diagnostic and prognostic marker for esophageal squamous cell carcinoma

BACKGROUND

Leucine-rich repeat-coupled receptor 6 (LGR6) is a marker of the skin, nails, and other types of adult tissue stem cells and has been widely found to be related to the development and progression of a variety of cancer types. The clinical significance and biological function of LGR6 in esophageal squamous cell carcinoma (ESCC) have not been determined.

METHODS

The expression of LGR6 at the transcriptional level was analyzed by searching the TCGA and UCSC data sets. Immunohistochemistry, WB, and q-PCR were used to detect the expression of LGR6 in ESCC and adjacent normal tissues. LGR6 PPI networks and KEGG pathways were used to analyze the potential biological functions of LGR6.

RESULTS

The expression of LGR6 in ESCC tissues was significantly higher than that in normal tissues and was negatively correlated with the differentiation degree of ESCC and the prognosis of the patients but not closely correlated with the TNM stage of ESCC. PPI networks showed that LGR6 had a close interaction with RSPO1, RSPO2, RSPO3, and RSPO4. KEGG pathway analysis showed that LGR6 activated the Wnt/β-catenin signaling pathway by binding with RSPO ligands to promote the progression of ESCC.

CONCLUSION

LGR6 can serve as a potential diagnostic and prognostic marker for ESCC.

Immunoexpression of LGR4 and Β-Catenin in Gastric Cancer and Normal Gastric Mucosa

Background:

We evaluated the immunoexpression of LGR4 and β-catenin in primary gastric carcinomas, lymph node metastases and histologically normal gastric mucosa in the surgical margins of gastric primary tumours.

Methods:

We performed a cross-sectional, observational study, based on 75 gastric carcinoma specimens from gastrectomies conducted at the hospital of the Federal University of Ceará, Brazil. The samples were analysed by tissue microarray and immunohistochemistry. Chi-square, Fisher’s exact test and Pearson’s linear regression were used in this study.

Results:

LGR4 expression was greater in the histologically normal gastric mucosa (basal third of the epithelial thickness) of the tumour surgical resection margin than in the cases of primary carcinomas (P<0.001, mainly diffuse-histotype cancer margins), and also in the number of cells stained in the normal mucosa (P<0.0001). Primary intestinal-type carcinomas showed greater positivity for LGR4 than diffuse tumours (59% vs 13%, P<0.0001) and in these the positivity was higher in the metastases (P=0.0242). The membranous immunoexpression of β-catenin was ubiquitous in the normal mucosa and present in 2/3 of the positive carcinomas. In only one case, nuclear β-catenin expression was observed. Most LGR4-positive cases were stained for membranous β-catenin but not the opposite (P<0.01).

Conclusion:

LGR4 is a likely biomarker of stem cells in the normal gastric mucosa and carcinomas of the stomach, not specific to cancer cells and positively associated with cell proliferation. LGR4 immunoexpression is more frequent and found in a larger number of cells in normal tissues than in tumour samples. Expression of β-catenin in the junctional membrane-complex occurred predominantly, in positive cases of gastric carcinomas and very rarely in the nucleus. LGR4 apparently influenced the membranous expression of β-catenin. These findings suggest a controversial role for LGR4, related to proliferative status and inversely related to tumour progression, in contrast to most previous reports.

G protein-coupled receptor LGR6 is an independent risk factor for colon adenocarcinoma

LGR6 is a member of the G protein-coupled receptor family that plays a tumor-suppressive role in colon cancer. However, the relationship between LGR6 expression in patients and clinicopathological factors remains unclear. This study aimed to clarify whether the expression level of LGR6 is correlated with colon adenocarcinoma progression. Immunohistochemistry was used to detect LGR6 expression in colon adenoma tissues (n = 21), colon adenocarcinoma tissues (n = 156), and adjacent normal tissues (n = 124). The expression levels of LGR6 in colon adenoma and adenocarcinoma were significantly higher than those in normal colon epithelial tissues (P < 0.001). Low LGR6 expression predicted a short overall survival in patients with colon adenocarcinoma (log-rank test, P = 0.016). Univariate and multivariate survival analyses showed that, in addition to N and M classification, LGR6 expression served as an independent prognostic factor. Thus, low expression of LGR6 can be used as an independent prognostic parameter in patients with colon adenocarcinoma.

Downregulation of Lgr6 inhibits proliferation and invasion and increases apoptosis in human colorectal cancer

The aim of the present study was to analyze the role of leucine‑rich repeat‑containing G‑protein coupled receptor 6 (Lgr6) in the proliferation and invasion of colorectal cancer (CRC) cells, and to investigate its possible mechanisms. The expression of Lgr6 in CRC tissues was observed by real time‑quantitative polymerase chain reaction and western blotting. Then cell viability, apoptosis and cell invasion was measured by MTT, flow cytometry or Matrigel‑Transwell system, respectively in CRC cells after transfected with Lgr6 siRNA or Lgr6 vector. Furthermore, the expression of apoptosis‑associated protein and PI3K/AKT signaling (phosphorylated‑PI3K, phosphorylated‑AKT, t‑PI3K, t‑AKT) were measured by real‑time PCR/or western blot analysis. The results demonstrated that the level of Lgr6 was higher in CRC tissues than that in adjacent tissues, and Lgr6 overexpression increased CRC proliferation, and invasion of CRC cells in vitro. Notably, suppressing the expression of Lgr6 in CRC cells increased the expression of B‑cell lymphoma-2 (Bcl‑2)‑associated X protein and caspase‑3, but decreased the expression of Bcl‑2 at the mRNA and protein levels. Lgr6 also had the ability to regulate the phosphoinositide 3‑kinase/AKT signaling pathway. It was concluded that Lgr6 has a tumor‑promoting role in the development of CRC, and may serve as a potential diagnostic and prognostic biomarker for the disease.

JTC-801 exerts anti-proliferative effects in human osteosarcoma cells by inducing apoptosis

BACKGROUND

The research of G protein-coupled receptors (GPCRs) is a promising strategy for drug discovery. In cancer therapy, there is a need to discover novel agents that can inhibit proliferation and induce apoptosis in cancer cells. JTC-801 is a novel GPCR antagonist with the function of reversing pain and anxiety symptoms. This study aims to investigate the antitumor effects of JTC-801 on human osteosarcoma cells (U2OS) and elucidate the underlying mechanism.

MATERIALS AND METHODS

The Cell Counting Kit-8 assay was used to detect the viability of U2OS cells treated with JTC-801 in vitro. The cell apoptosis was evaluated using a flow cytometry assay with Annexin V-FITC/PI double staining. The inhibitory effect of JTC-801 on invasion and migration of U2OS cells were determined by the Transwell assays. Western blot assay was performed to measure the levels of proteins related to cell apoptosis and its mechanism.

RESULTS

The JTC-801 significantly decreased the viability of U2OS cells (p < .05) as a result of its anti-proliferative effect through induction of apoptosis associated with activation of BAX, Caspase-3 and down-regulating BCL-2 expression. The invasive and migratory cells were obviously reduced after JTC-801 treatment (p < .05). Further, the phosphorylated AKT, mTOR and active p70 S6 protein kinase in the PI3K/AKT signaling pathway were obviously lessened in the JTC-801 treated U2OS group (p < .05).

CONCLUSIONS

JTC-801 may exert osteosarcoma cell growth inhibition by promoting cell apoptosis, through PI3K/AKT signaling pathway participation.

Upregulation of RSPO2-GPR48/LGR4 signaling in papillary thyroid carcinoma contributes to tumor progression

The signaling pathway involving the R-spondins and its cognate receptor, GPR48/LGR4, is crucial in development and carcinogenesis. However, the functional implications of the R-spondin-GPR48/LGR4 pathway in thyroid remain to be identified. The aim of this study was to investigate the role of R-spondin-GPR48/LGR4 signaling in papillary thyroid carcinomas. We retrospectively reviewed a total of 214 patients who underwent total thyroidectomy and cervical lymph node dissection for papillary thyroid carcinoma. The role of GPR48/LGR4 in proliferation and migration was examined in thyroid cancer cell lines. R-spondin 2, and GPR48/LGR4 were expressed at significantly higher levels in thyroid cancer than in normal controls. Elevated GPR48/LGR4 expression was significantly associated with tumor size (P=0.049), lymph node metastasis (P=0.004), recurrence (P=0.037), and the BRAFV600E mutation (P=0.003). Moreover, high GPR48/LGR4 expression was an independent risk factor for lymph node metastasis (P=0.027) and the BRAFV600E mutation (P=0.009). in vitro assays demonstrated that elevated expression of GPR48/LGR4 promoted proliferation and migration of thyroid cancer cells, whereas downregulation of GPR48/LGR4 decreased proliferation and migration by inhibition of the β-catenin pathway. Moreover, treatment of thyroid cancer cells with exogenous R-spondin 2 induced activation of the β-catenin pathway through GPR48/LGR4. The R-spondin 2-GPR48/LGR4 signaling axis also induced the phosphorylation of ERK, as well as phosphorylation of LRP6 and serine 9 of GSK3β. Our findings demonstrate that upregulation of the R-spondin 2-GPR48/LGR4 pathway contributes to tumor aggressiveness in papillary thyroid carcinoma by promoting ERK phosphorylation, suggesting that this pathway represents a novel therapeutic target for treatment of differentiated thyroid cancer.

LGR5 and LGR6 in stem cell biology and ovarian cancer

Wnt signaling plays a fundamental role in patterning of the embryo and maintenance of stem cells in numerous epithelia. Epithelial stem cells are closeted in niches created by surrounding differentiated cells that express secreted Wnt and R-spondin proteins that influence proliferation rate and fate determination of stem cell daughters. R-spondins act through the LGR receptors to enhance Wnt signaling. This close association of stem cells with more differentiated regulatory cells expressing Wnt-pathway ligands is a feature replicated in all of the epithelial stem cell systems thus far examined. How the stem cell niche operates through these short-range interactions is best understood for the crypts of the gastrointestinal epithelium and skin. Less well understood are the stem cells that function in the ovarian surface epithelium (OSE) and fallopian tube epithelium (FTE). While the cuboidal OSE appears to be made up of a single cell type, the cells of the FTE progress through a life cycle that involves differentiation into ciliated and secretory subtypes that are eventually shed into the lumen in a manner similar to the gastrointestinal epithelium. Available evidence suggests that high grade serous ovarian carcinoma (HGSOC) originates most often from stem cells in the FTE and that Wnt signaling augmented by LGR6 supports tumor development and progression. This review summarizes current information on LGR5 and LGR6 in the OSE and FTE and how their niches are organized relative to that of the gastrointestinal epithelium and skin.

Leucine-rich repeat-containing G protein-coupled receptor 4 (Lgr4) is necessary for prostate cancer metastasis via epithelial-mesenchymal transition

Prostate cancer is a highly penetrant disease among men in industrialized societies, but the factors regulating the transition from indolent to aggressive and metastatic cancer remain poorly understood. We found that men with prostate cancers expressing high levels of the G protein-coupled receptor LGR4 had a significantly shorter recurrence-free survival compared with patients with cancers having low LGR4 expression. LGR4 expression was elevated in human prostate cancer cell lines with metastatic potential. We therefore generated a novel transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model to investigate the role of Lgr4 in prostate cancer development and metastasis in vivo TRAMP Lgr4^-/- mice exhibited an initial delay in prostate intraepithelial neoplasia formation, but the frequency of tumor formation was equivalent between TRAMP and TRAMP Lgr4^-/- mice by 12 weeks. The loss of Lgr4 significantly improved TRAMP mouse survival and dramatically reduced the occurrence of lung metastases. LGR4 knockdown impaired the migration, invasion, and colony formation of DU145 cells and reversed epithelial-mesenchymal transition (EMT), as demonstrated by up-regulation of E-cadherin and decreased expression of the EMT transcription factors ZEB, Twist, and Snail. Overexpression of LGR4 in LNCaP cells had the opposite effects. Orthotopic injection of DU145 cells stably expressing shRNA targeting LGR4 resulted in decreased xenograft tumor size, reduced tumor EMT marker expression, and impaired metastasis, in accord with our findings in TRAMP Lgr4^-/- mice. In conclusion, we propose that Lgr4 is a key protein necessary for prostate cancer EMT and metastasis.

GPCR48/LGR4 promotes tumorigenesis of prostate cancer via PI3K/Akt signaling pathway

G-protein-coupled receptor (GPCR) 48, also known as leucine-rich repeat-containing G-protein-coupled receptor (LGR) 4, is an orphan receptor belonging to the GPCR superfamily, which plays an important role in the development of various organs and multiple cancers. However, the function of GPCR48/LGR4 in prostate cancer has not been fully investigated. Herein, GPCR48/LGR4 was overexpressed and silenced in prostate cancer cells via plasmid and shRNA transfection, respectively. The expression of GPCR48/LGR4 in mRNA and protein levels was analyzed using RT-qPCR and Western blotting, respectively. Subsequently, we demonstrated the effects of GPCR48/LGR4 on the migration, invasion, proliferation and apoptosis of prostate cancer cells, including Du145 and PC-3 cells. Next, we investigated the relationship between GPCR48/LGR4 and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt signaling pathway. The results showed that the overexpression of GPCR48/LGR4 was associated with the up-regulation of Akt, a key effector of PI3K/Akt signaling pathway, which meantime up-regulated the expression of mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3β (GSK-3β), while down-regulated forkhead box, class O (FOXO), all of whom are the downstream targets of PI3K/Akt signaling pathway. Hence, the results suggested that GPCR48/LGR4 may regulate prostate cancer cells and tumor growth via the PI3K/Akt signaling pathway and could provide a better therapeutic target for the diagnosis and treatment of prostate cancer.

Hunting for the function of orphan GPCRs - beyond the search for the endogenous ligand

Seven transmembrane-spanning proteins (7TM), also called GPCRs, are among the most versatile and evolutionary successful protein families. Out of the 400 non-odourant members identified in the human genome, approximately 100 remain orphans that have not been matched with an endogenous ligand. Apart from the classical deorphanization strategies, several alternative strategies provided recent new insights into the function of these proteins, which hold promise for high therapeutic potential. These alternative strategies consist of the phenotypical characterization of organisms silenced or overexpressing orphan 7TM proteins, the search for constitutive receptor activity and formation of protein complexes including 7TM proteins as well as the development of synthetic, surrogate ligands. Taken together, a variety of ligand-independent functions can be attributed to orphan 7TM proteins that range from constitutive activity to complex formation with other proteins and include 'true' orphans for which no ligand exist and 'conditional' orphans that behave like orphans in the absence of ligand and as non-orphans in the presence of ligand.

[Ways to personalized medicine for gastric cancer]

Gastric cancer is the fourth most common tumor and the second most common cause of cancer-related deaths in the world. Approximately 70 % of the patients already have lymph node metastases at the time of the diagnosis leading to a median overall survival time of 16.7 months. Complete resection of the primary tumor with D2 lymphadenectomy offers the only chance of cure in the early stages of the disease. Survival of more locally advanced gastric cancer was improved by the introduction of perioperative, adjuvant and palliative chemotherapy of gastric cancer; however, the identification of novel predictive and diagnostic targets is urgently needed. Our own studies on gastric cancer biology identified several putative tumor biologically relevant G-protein-coupled receptors (e.g. AT1R, AT2R, CXCR4, FZD7, LGR4, LGR5, LGR6). Some of these receptors are also putative stem cell markers and may serve as future targets of an individualized therapy of gastric cancer.

A novel autoantibody test for the detection of pre-neoplastic lung lesions

Background

Atypical adenomatous hyperplasia (AAH) and squamous cell dysplasia (SCD) are associated with the development of malignant lesions in the lung. Accurate diagnosis of AAH and SCD could facilitate earlier clinical intervention and provide useful information for assessing lung cancer risk in human populations. Detection of AAH and SCD has been achieved by imaging and bronchoscopy clinically, but sensitivity and specificity remain less than satisfactory. We utilized the ability of the immune system to identify lesion specific proteins for detection of AAH and SCD.

Methods

AAH and SCD tissue was surgically removed from six patients of Chinese descent (3 AAH and 3 SCD) with corresponding serum samples. Total RNA was extracted from the tissues and a cDNA library was generated and incorporated into a T7 bacteriophage vector. Following enrichment to remove "normal" reactive phages, a total of 200 AAH related and 200 SCD related phage clones were chosen for statistical classifier development and incorporation into a microarray. Microarray slides were tested with an independent double-blinded population consisting of 100 AAH subjects, 100 SCD subjects and 200 healthy control subjects.

Results

Sensitivity of 82% and specificity of 70% were achieved in the detection of AAH using a combination of 9 autoantibody biomarkers. Likewise, 86% sensitivity and 78% specificity were achieved in the detection of SCD using a combination of 13 SCD-associated markers. Sequencing analysis identified that most of these 22 autoantibody biomarkers had known malignant associations.

Conclusions

Both diagnostic values showed promising sensitivity and specificity in detection of pre-neoplastic lung lesions. Hence, this technology could be a useful non-invasive tool to assess lung cancer risk in human populations.

GPR48, a poor prognostic factor, promotes tumor metastasis and activates β-catenin/TCF signaling in colorectal cancer

G-protein-coupled receptor 48 (GPR48) is an orphan receptor belonging to the G-protein-coupled receptors family, which plays an important role in the development of various organs and cancer development and progression such as gastric cancer and colorectal cancer (CRC). However, the prognostic value of GPR48 expression in patients with CRC has not been reported. In this study, we observed that GPR48 was overexpressed in primary CRC and metastatic lymph nodes and closely correlated with tumor invasion and metastasis. Multivariate analysis indicated that high GPR48 expression was a poor prognostic factor for overall survival in CRC patients. In vitro and in vivo assays demonstrated that enforced expression of GPR48 contributed to enhance migration and invasion of cancer cells and tumor metastasis. In addition, we found that GPR48 increased nuclear β-catenin accumulation, T-cell factor 4 (TCF4) transcription activity, and expression of its target genes including Cyclin D1 and c-Myc in CRC cells. Correlation analysis showed that GPR48 expression in CRC tissues was positively associated with β-catenin expression. Upregulation of GPR48 resulted in increased phosphorylation of glycogen synthase kinase 3β, Akt and extracellular signal-regulated kinase 1/2 (ERK1/2) in CRC cells, while inhibition of PI3K/Akt and mitogen-activated protein kinase /ERK1/2 pathways was sufficient to abolish the effect of GPR48 on β-catenin/TCF signaling. Taken together, GPR48 could serve as both a prognostic biomarker and a therapeutic target for resectable CRC patients.