Over-expression of LGR5 correlates with poor survival of colon cancer in mice as well as in patients

QPH-FR: A Novel Quinoa Peptide Enhances Chemosensitivity by Targeting Leucine-Rich Repeat-Containing G Protein-Coupled Receptor 5 in Colorectal Cancer

Chemoresistance is one of the difficulties in the treatment of colorectal cancer (CRC), and the enhanced stemness of tumor cells is the underlying contributing factor. Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a classical marker of CRC stem cells and can be an important potential target for CRC chemotherapy. Quinoa, a protein-rich plant, offers potential as a source of high-quality active peptides. Novelly, the study obtained quinoa protein hydrolysate (QPH) from whole quinoa grains by simulated digestion. In vivo experiments revealed that the tumor volume in the 5-FU+QPH group decreased from 145.90 ± 13.35 to 94.49 ± 13.05 mm3 in the 5-FU group, suggesting that QPH enhances the chemosensitivity of CRC. Further, the most effective peptide QPH-FR from 631 peptides in QPH was screened by activity prediction, molecular docking, and experimental validation. Mechanistically, QPH-FR competitively suppressed the formation of the LGR5/RSPO1 complex by binding to LGR5, causing RNF43/ZNRF3 to ubiquitinate the FZD receptor, thereby suppressing the Wnt/β-catenin signaling pathway and exerting stemness inhibition. In summary, the study proposes that a novel peptide QPH-FR from quinoa elucidates the mechanism by which QPH-FR targets LGR5 to enhance chemosensitivity, providing theoretical support for the development of chemotherapeutic adjuvant drugs based on plant peptides.

Colorectal Cancer Stem Cell Biomarkers: Biological Traits and Prognostic Insights

Due to self-renewal, differentiation, and limitless proliferation properties, Cancer Stem Cells (CSCs) increase the probability of tumor development. These cells are identified by using CSC markers, which are highly expressed proteins on the cell surface of CSCs. Recently, the therapeutic application of CSCs as novel biomarkers improved both the prognosis and diagnosis outcome of colorectal Cancer. In the present review, we focused on a specific panel of colorectal CSC markers, including LGR5, ALDH, CD166, CD133, and CD44, which offers a targeted and comprehensive analysis of their functions. The selection criteria for these markers cancer were based on their established significance in Colorectal Cancer (CRC) pathogenesis and clinical outcomes, providing novel insights into the CSC biology of CRC. Through this approach, we aim to elevate understanding and stimulate further research for developing effective diagnostic and therapeutic strategies in CRC.

The Expression of Stem Cell Marker LGR5 and Its Coexpression with Β-Catenin in Sporadic Colorectal Carcinoma and Adenoma: A Comparative Immunohistochemical Study

Background: LGR5 is one of the most important stem cell markers for colorectal cancer (CRC), as it potentiates Wnt/Β-catenin signaling. The well-characterized deregulation of Wnt/Β-catenin signaling that occurs during adenoma/carcinoma sequence in CRC renders LGR5 a hopeful therapeutic target. We assessed the immunohistochemical expression of LGR5 and Β-catenin in normal colonic and tumorous lesions with a clinicopathological correlation. Methods: Tissue blocks and clinical data of 50 selected cases were included: 8 from normal mucosa, 12 cases of adenoma, and 30 cases of CRC, where sections were cut and re-examined and the immunohistochemical technique was conducted using anti-LGR5 and anti-Β-catenin to measure the staining density. Results: There was no expression of LGR5 in normal mucosa compared to samples of adenoma and CRC samples. The association analysis showed that CRC specimens were more likely to have strong LGR5 and Β-catenin expressions than the other two groups (p = 0.048 and p < 0.001, respectively). Specimens with high-grade dysplastic adenoma were more likely to express moderate-to-strong expression of LGR5 and Β-catenin (p = 0.013 and p = 0.036, respectively). In contrast, there were no statistically significant associations between LGR5 and Β-catenin expression with grade and stage. Conclusion: These results suggest and support the possible role of LGR5 as a potential marker of cancer stem cells in sporadic colorectal carcinogenesis in addition to a prognostic value for LGR5 and Β-catenin in adenomatous lesions according to immunohistochemical expression density. A potential therapeutic role of LGR5 in CRC is suggested for future studies based on its role in pathogenesis.

Enhanced binding of β-catenin and β-TrCP mediates LMPt's anti-CSCs activity in colorectal cancer

Cancer stem cells (CSCs), a subpopulation of tumor cells with the features of self-renewal, tumor initiation, and insensitivity to common physical and chemical agents, are the key to cancer relapses, metastasis, and resistance. Accessible CSCs inhibitory strategies are primarily based on small molecule drugs, yet toxicity limits their application. Here, we report a liposome loaded with low toxicity and high effectiveness of miriplatin, lipo-miriplatin (LMPt) with high miriplatin loading, and robust stability, exhibiting a superior inhibitory effect on CSCs and non-CSCs. LMPt predominantly inhibits the survival of oxaliplatin-resistant (OXA-resistant) cells composed of CSCs. Furthermore, LMPt directly blocks stemness features of self-renewal, tumor initiation, unlimited proliferation, metastasis, and insensitivity. In mechanistic exploration, RNA sequencing (RNA-seq) revealed that LMPt downregulates the levels of pro-stemness proteins and that the β-catenin-mediated stemness pathway is enriched. Further research shows that either in adherent cells or 3D-spheres, the β-catenin-OCT4/NANOG axis, the vital pathway to maintain stemness, is depressed by LMPt. The consecutive activation of the β-catenin pathway induced by mutant β-catenin (S33Y) and OCT4/NANOG overexpression restores LMPt's anti-CSCs effect, elucidating the key role of the β-catenin-OCT4/NANOG axis. Further studies revealed that the strengthened binding of β-catenin and β-TrCP initiates ubiquitination and degradation of β-catenin induced by LMPt. In addition,the Apc^Min/+transgenicmouse model, in which colon tumors are spontaneously formed, demonstrates LMPt's potent anti-non-CSCs activity in vivo.

High IGKC-Expressing Intratumoral Plasma Cells Predict Response to Immune Checkpoint Blockade

Resistance to Immune Checkpoint Blockade (ICB) constitutes the current limiting factor for the optimal implementation of this novel therapy, which otherwise demonstrates durable responses with acceptable toxicity scores. This limitation is exacerbated by a lack of robust biomarkers. In this study, we have dissected the basal TME composition at the gene expression and cellular levels that predict response to Nivolumab and prognosis. BCR, TCR and HLA profiling were employed for further characterization of the molecular variables associated with response. The findings were validated using a single-cell RNA-seq data of metastatic melanoma patients treated with ICB, and by multispectral immunofluorescence. Finally, machine learning was employed to construct a prediction algorithm that was validated across eight metastatic melanoma cohorts treated with ICB. Using this strategy, we have unmasked a major role played by basal intratumoral Plasma cells expressing high levels of IGKC in efficacy. IGKC, differentially expressed in good responders, was also identified within the Top response-related BCR clonotypes, together with IGK variants. These results were validated at gene, cellular and protein levels; CD138+ Plasma-like and Plasma cells were more abundant in good responders and correlated with the same RNA-seq-defined fraction. Finally, we generated a 15-gene prediction model that outperformed the current reference score in eight ICB-treated metastatic melanoma cohorts. The evidenced major contribution of basal intratumoral IGKC and Plasma cells in good response and outcome in ICB in metastatic melanoma is a groundbreaking finding in the field beyond the role of T lymphocytes.

PD-L1 interacts with Frizzled 6 to activate β-catenin and form a positive feedback loop to promote cancer stem cell expansion

Cancer stem cells (CSCs) drive tumor initiation, progression, metastasis, and drug resistance. We report here that programmed cell death ligand 1 (PD-L1) is constitutively expressed in cancer cells to maintain and expand CSC through a novel mechanism in addition to promoting cancer cell immune evasion. We discovered that PD-L1 interacts with receptor Frizzled 6 to activate β-catenin signaling and increase β-catenin-targeted gene expression, such as a putative stem cell marker leucine-rich-repeat-containing G-protein-coupled receptor 5. Blockage of PD-L1 function, using a specific small hairpin RNA or a specific antibody, inhibits disease progression by reducing the CSC population in both colorectal and breast tumors. Moreover, β-catenin conversely regulates PD-L1 expression through a β-catenin complex binding site in the PD-L1 promoter. Our discoveries reveal that besides assistant tumor cell immune escaping, PD-L1 and β-catenin signaling form a positive feedback loop to promote cancer progression through CSC maintenance and expansion.

Drug screening by uniform patient derived colorectal cancer hydro-organoids

As the importance of organoids increases, the need to develop organoid culture systems suitable for basic biological and clinical applications is being emphasized. However, there is still an unmet need to produce functionally complex and scalable uniform organoids. Here, we demonstrate a scalable organoid production platform with 8 well strips and a total of 8 × 9 microwells per strip using organoids derived from colorectal cancer tissue. The new culture platform is a format in which single cells are self-organized into organoids in culture medium supplemented with 2% Matrigel. It is functionally compatible with existing 96 well plates and Matrigel based conventional organoid culture methods. The consistency, uniformity and reproducibility of organoid produced on the new platform have been significantly improved compared to those of conventional plates. Importantly, Hydro-organoids are functionally identical to conventional Matrigel organoids, but show better consistency in drug screening. Our results show the possibility that Hydro-organoids can be used in high-throughput assays and incorporated into drug screening models to predict clinical outcomes.

Immune infiltration and immune gene signature predict the response to fluoropyrimidine-based chemotherapy in colorectal cancer patients

Fluoropyrimidine-based chemotherapy is an essential component of systemic chemotherapy for colorectal cancer (CRC). The immune response is implicated in chemotherapy-induced cytotoxicity. Here, we reported an immune risk (Imm-R) model for prognostic prediction in patients receiving fluoropyrimidine-based chemotherapy. Gene expression profiles and corresponding clinical information were collected from four data sets and divided into training set (n = 183) and validation set (validation set1: n = 34; validation set2: n = 99). The composition of 22 tumor-infiltrating immune cells (TIICs) populations was characterized with the CIBERSORT deconvolution algorithm. A prognostic Imm-R model for predicting overall survival was established by performing least absolute shrinkage and selection operator (LASSO) penalized COX regression analysis. T follicular helper cells and M0 macrophages were associated with better survival, while eosinophils were associated with worse survival. TIICs signature was constructed based on the above three immune cell types. Furthermore, a Imm-R model was created by integrating TIICs signature with immune-related genes (IRGs), which effectively in distinguishing CRC patients with poorer prognosis. The Imm-R model was associated with activation of the TGF-beta signaling and suppression of DNA damage. Results of this research provide new insights into the role of immunity for in fluoropyrimidine-based chemotherapy as well as a useful tools to predict the outcome of CRC patients receiving fluoropyrimidine-based chemotherapy.

Differential mechanisms of autophagy in cancer stem cells: Emphasizing gastrointestinal cancers

Gastrointestinal (GI) cancers are one of the most common forms of malignancies and still are the most important cause of cancer-related mortality worldwide. Autophagy is a conserved catabolic pathway involving lysosomal degradation and recycling of whole cellular components, which is essential for cellular homeostasis. For instance, it acts as a pivotal intracellular quality control and repair mechanism but also implicated in cell reformation during cell differentiation and development. Indeed, GI cancer stem cells (CSCs) are thought to be responsible for tumour initiation, traditional therapies resistance, metastasis and tumour recurrence. Molecular mechanisms of autophagy in normal vs CSCs gain great interest worldwide. Here, we shed light on the role of autophagy in normal stem cells differentiation for embryonic progression and its role in maintaining the activity and self-renewal capacity of CSCs which offer novel viewpoints on promising cancer therapeutic strategies based on the differential roles of autophagy in CSCs.

Clinical implications of cancer stem cells in digestive cancers: acquisition of stemness and prognostic impact

Digestive system cancers are the most frequent cancers worldwide and often associated with poor prognosis because of their invasive and metastatic characteristics. Recent studies have found that the plasticity of cancer cells can impart cancer stem-like properties via the epithelial-mesenchymal transition (EMT). Cancer stem-like properties such as tumor initiation are integral to the formation of metastasis, which is the main cause of poor prognosis. Numerous markers of cancer stem cells (CSCs) have been identified in many types of cancer. Therefore, CSCs, via their stem cell-like functions, may play an important role in prognosis after surgery. While several reports have described prognostic analysis using CSC markers, few reviews have summarized CSCs and their association with prognosis. Herein, we review the prognostic potential of eight CSC markers, CD133, CD44, CD90, ALDH1A1, EPCAM, SOX2, SOX9, and LGR5, in digestive cancers including those of the pancreas, colon, liver, gastric, and esophagus.

Prognostic implication of ABC transporters and cancer stem cell markers in patients with stage III colon cancer receiving adjuvant FOLFOX-4 chemotherapy

Cancer stem cell (CSC) and ATP-binding cassette (ABC) transporters are associated with treatment resistance and outcomes of patients with cancer. The present study investigated the prognostic implications of pre-therapeutic expression of ABC transporters and CSC markers in patients with colon cancer (CC) who received adjuvant 5-fluorouracil, leucovorin and oxaliplatin combination therapy (FOLFOX-4). The immunohistochemical expression of 3 ABC transporters, including ABC subfamily C member 2 (ABCC2), ABCC3 and ABC subfamily G member 2 (ABCG2), and 3 CSC markers, including sex determining region Y-box 2 (SOX2), leucine-rich repeat-containing G protein-coupled receptor 5 and aldehyde dehydrogenase 1, were determined in 164 CC tissues from patients with stage III CC, who underwent postoperative FOLFOX-4 chemotherapy. The association between the protein expression and patients' prognoses was statistically analyzed. ABCG2 was associated with favorable overall survival rate (OS; P=0.001), and ABCC2, ABCG2 and SOX2 were associated with increased disease-free survival rate (DFS; P=0.001, 0.002 and 0.013, respectively). In multivariate analyses, ABCG2 was an independent prognostic factor for OS [hazard ratio (HR)=2.877; P=0.046], and ABCC2 and SOX2 were independent prognostic factors for DFS (HR=2.831; P=0.014; HR=2.558, P=0.020, respectively). ABCC2, ABCG2 and SOX2 may be promising prognostic markers for patients with CC receiving FOLFOX-4 therapy.

Overexpression of cancer stem cell marker Lgr5 in colorectal cancer patients and association with clinicopathological findings

BACKGROUND

To determine the expression of cancer stem cell marker Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) in colorectal carcinoma samples compared to normal adjacent tissue and any possible association with clinicopathological findings.

METHODS

This study was performed on forty samples of cancerous colorectal tissues (case group) and their adjacent normal mucosa (control group) in Imam Khomeini Hospital (Sari, Mazandaran, Iran). Expression of Lgr5 in tissue sections was done by immunohistochemistry. Statistical analysis was carried out using SPSS software.

RESULTS

Forty colorectal cancer patients including 21 males (57.8±11.6 years) and 19 females (58.4±12.77 years) were enrolled. Lgr5 was overexpressed in tumoral samples than normal adjacent tissues (77.5% vs 27.5%, p<0.001). Also, no association was found between primary tumor, regional lymph nodes, invasion, histological type, grade, distant metastasis and IHC results. Patients with low Lgr5 expression had a better survival rate than patients with high expression but this was not statistically significant (p=0.121).

CONCLUSION

The higher immunoreactivity of Lgr5 in colorectal cancer tissues may indicate its role as a cancer stem cell marker in tumor carcinogenesis and patient's survival however; Lgr5 is not associated with pathological prognostic variables.

Mesenchymal marker and LGR5 expression levels in circulating tumor cells correlate with colorectal cancer prognosis

PURPOSE

The presence of circulating tumor cells (CTCs) has been found to correlate with colorectal cancer (CRC) prognosis, whereas epithelial-mesenchymal transition (EMT) in CTCs has been found to be associated with CRC metastasis. LGR5 is a known target of Wnt signaling and plays an important role in CRC development. The aim of this study was to assess the clinical relevance of EMT and LGR5 expression in CTCs from CRC patients.

METHODS

Sixty-six CRC patients were included in this study. The detection and expression of EMT phenotypes in CTCs from these patients were assessed using CanPatrol™ CTC enrichment and mRNA in situ hybridization (ISH), respectively. LGR5 expression in the CTCs was assessed using mRNA ISH.

RESULTS

CTCs were detected in 86.4% (57/66) of the CRC patients included. Both the numbers of total CTCs and of CTCs displaying a mesenchymal phenotype (M+ CTCs) were found to significantly correlate with advanced disease stages and the occurrence of metastasis (p < 0.05). An adjusted multivariate analysis also indicated that the number of M+ CTCs significantly correlated with the occurrence of metastasis (p = 0.031). Additionally, we found that a high LGR5 expression level significantly correlated with the occurrence of metastasis (p < 0.05). We also found that the presence of ≥ 6 CTCs or ≥ 3 M+ CTCs per 5 ml blood significantly correlated with disease progression (p < 0.05). Patients with ≥ 6 CTCs or ≥ 3 M+ CTCs per 5 ml blood were found to exhibit poorer progression-free survival (PFS) and overall survival (OS) rates (p < 0.05 in all cases). Using Cox regression analyses, we found that only total CTC numbers remained as independent prognostic factors for a worse PFS (p = 0.043).

CONCLUSIONS

From our data we conclude that CTC numbers and EMT phenotypes may serve as prognostic markers for disease progression and metastasis in CRC patients. In addition, we conclude that LGR5 expression in CTCs may serve as a marker for CRC metastasis.

Targeting LGR5 in Colorectal Cancer: therapeutic gold or too plastic?

Leucine-rich repeat-containing G-protein coupled receptor (LGR5 or GPR49) potentiates canonical Wnt/β-catenin signalling and is a marker of normal stem cells in several tissues, including the intestine. Consistent with stem cell potential, single isolated LGR5⁺ cells from the gut generate self-organising crypt/villus structures in vitro termed organoids or 'mini-guts', which accurately model the parent tissue. The well characterised deregulation of Wnt/β-catenin signalling that occurs during the adenoma-carcinoma sequence in colorectal cancer (CRC) renders LGR5 an interesting therapeutic target. Furthermore, recent studies demonstrating that CRC tumours contain LGR5⁺ subsets and retain a degree of normal tissue architecture has heightened translational interest. Such reports fuel hope that specific subpopulations or molecules within a tumour may be therapeutically targeted to prevent relapse and induce long-term remissions. Despite these observations, many studies within this field have produced conflicting and confusing results with no clear consensus on the therapeutic value of LGR5. This review will recap the various oncogenic and tumour suppressive roles that have been described for the LGR5 molecule in CRC. It will further highlight recent studies indicating the plasticity or redundancy of LGR5⁺ cells in intestinal cancer progression and assess the overall merit of therapeutically targeting LGR5 in CRC.

Jade family PHD finger 3 (JADE3) increases cancer stem cell-like properties and tumorigenicity in colon cancer

Jade family PHD finger 3 (JADE3) plays a role in inducing histone acetylation during transcription, and is involved in the progression of several human cancers; however, its role in colon cancer remains unclear. Herein, we found that JADE3 was markedly upregulated in colon cancer tissues and significantly correlated with cancer progression, and predicted shorter patient survival. Further, JADE3 was expressed much higher in colon cancer cell lines that are enriched with a stem-like signature. Overexpression of JADE3 increased, while silencing JADE3 reduced cancer stem cell-like traits in colon cancer cells in vitro and in vivo. Importantly, silencing of JADE3 strongly impaired the tumor initiating capacity of colon cancer cells in vivo. Furthermore, JADE3 interacted with the promoters of colon stem cell marker LGR5 and activated its transcription, by increasing the occupancy of p300 acetyltransferase and histone acetylation on the promoters. Finally, we found that JADE3 expression was substantially induced by Wnt/β-catenin signaling. These findings suggest an oncogenic role of JADE3 by regulating cancer stem cell-like traits in the colon cancer, and therefore JADE3 might be a potential therapeutic target for the treatment of colon cancer.

Expression and functional regulation of stemness gene Lgr5 in esophageal squamous cell carcinoma

Cancer stem cells (CSCs) are defined as a rare subpopulation of undifferentiated cells with biological characteristics that include the capacity for self-renewal, differentiation into various lineages, and tumor initiation. To explore the mechanism of CSCs in esophageal squamous cell carcinoma (ESCC), we focused on Leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), a target gene of the Wnt signaling pathway, which has been identified as a marker of intestinal stem cells and shown to be overexpressed in several human malignancies. Lgr5 expression was significantly correlated with lymph node metastasis, increased depth of invasion, increased tumor size, advanced differentiation, higher AJCC stage and poorer survival. Silencing of Lgr5 expression in the ESCC cell line KYSE450 by small interfering RNA (siRNA) strongly inhibited cell proliferation, migration and invasion ability, the expression of CSCs-related genes and Wnt/β-catenin signaling. In addition, Lgr5 was highly expressed in ESCC spheroid body cells, which were identified by high expression of CSCs-related genes, and high tumorigenicity in vivo. Taken together, these results demonstrate that Lgr5 activation of Wnt/β-catenin signaling is a potential mechanism to promote the progression of ESCC and ESCC stem cell renewal, and Lgr5 may be used as a molecular target for the development of treatments for ESCC.

Colon cancer-induced interleukin-35 inhibits beta-catenin-mediated pro-oncogenic activity

The occurrence and development of colon cancer is closely related to inflammation. Therefore, this study was conducted a current retrospective research to study the effect of IL-35 (interleukin 35), a newly identified anti-infective factor, on colon cancer development. The expression of IL-35 in colon cancer samples and their adjacent normal mucosa by real-time PCR, ELISA (enzyme-linked immunosorbent assay). The effect of IL-35 on patient survival, colon cancer progression, and its effect on Wnt/β-catenine signaling pathway was also assessed. IL-35 is minimally expressed in colon cancer tissues but is highly expressed in adjacent normal tissues. The down-regulation of IL-35 was significantly associated with the American Cancer Joint Committee stage and overall survival of colon cancer patients. The overexpression of IL-35 in colon cancer cells inhibits cell migration, invasion, proliferation, colony formation and cancer stem cells by inhibiting beta-catenin. IL-35 inhibits colon neoplasms in mouse. Our results suggest that IL-35 has an inhibitory effect on the development of colon cancer as a novel prognostic indicator and potential therapeutic target.

LGR5 expression is regulated by EGF in early colorectal adenomas and governs EGFR inhibitor sensitivity

Background:

LGR5 serves as a co-receptor for Wnt/β-catenin signalling and marks normal intestinal stem cells; however, its role in colorectal cancer (CRC) remains controversial. LGR5⁺ cells are known to exist outside the stem cell niche during CRC progression, and the requirement for epidermal growth factor (EGF) signalling within early adenomas remains to be fully elucidated.

Methods:

Epidermal growth factor and gefitinib treatments were performed in EGF-responsive LGR5⁺ early adenoma RG/C2 cells. 2D growth assays were measured using an IncuCyte. LGR5 or MEK1/2 silencing studies were executed using siRNA and LGR5 expression was assessed by qRT–PCR and immunoblotting. Ki67 level and cell cycle status were analysed by flow cytometry.

Results:

Epidermal growth factor suppresses expression of LGR5 at both the transcript and protein level in colorectal adenoma and carcinoma cells. Suppression of LGR5 reduces the survival of EGF-treated adenoma cells by increasing detached cell yield but also inducing a proliferative state, as evidenced by elevated Ki67 level and enhanced cell cycle progression. Repression of LGR5 further increases the sensitivity of adenoma cells to EGFR inhibition.

Conclusions:

LGR5 has an important role in the EGF-mediated survival and proliferation of early adenoma cells and could have clinical utility in predicting response of CRC patients to EGFR therapy.

Distribution of Lgr5-positive cancer cells in intramucosal gastric signet-ring cell carcinoma

Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is a putative intestinal stem cell marker that is also expressed in various tumors. To analyze its pathological characteristics in mucosal gastric signet-ring cell carcinoma (SRCC), we investigated Lgr5 expression in 35 intramucosal gastric SRCC patients using RNAscope, a newly developed RNA in situ hybridization technique. Lgr5 expression in individual tumor cells was scored semi-quantitatively from 0 to 400. Ki67 was also examined by immunohistochemistry, with a linear arrangement of Ki67-expressing cells present in 20 of 35 cases. This area of Ki67-expressing cells was topographically divided into upper, middle, and lower regions. All cases with linear Ki67 expression patterns also had Lgr5-positive cells arranged in a linear fashion in the lower area-which was distinct from the area of high Ki67 expression. The rate of Ki67 positivity in Lgr5-positive cells was significantly lower than that of Lgr5-negative cells in areas of high Ki67 expression. In intramucosal SRCC, the low mitotic activity of Lgr5-positive cells suggests that they may represent cancer stem cells as seen in other types of stomach carcinomas. Intramucosal SRCC may therefore contain stem cells expressing Lgr5 in the lower area of the lamina propria, akin to normal gastric pyloric mucosa.

Critical role of microbiota within cecal crypts on the regenerative capacity of the intestinal epithelium following surgical stress

Cecal crypts represent a unique niche that are normally occupied by the commensal microbiota. Due to their density and close proximity to stem cells, microbiota within cecal crypts may modulate epithelial regeneration. Here we demonstrate that surgical stress, a process that invariably involves a short period of starvation, antibiotic exposure, and tissue injury, results in cecal crypt evacuation of their microbiota. Crypts devoid of their microbiota display pathophysiological features characterized by abnormal stem cell activation as judged by leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) staining, expansion of the proliferative zone toward the tips of the crypts, and an increase in apoptosis. In addition, crypts devoid of their microbiota display loss of their regenerative capacity as assessed by their ability to form organoids ex vivo. When a four-member human pathogen community isolated from the stool of a critically ill patient is introduced into the cecum of mice with empty crypts, crypts become occupied by the pathogens and further disruption of crypt homeostasis is observed. Fecal microbiota transplantation restores the cecal crypts' microbiota, normalizes homeostasis within crypts, and reestablishes crypt regenerative capacity. Taken together, these findings define an emerging role for the microbiota within cecal crypts to maintain epithelial cell homeostasis in a manner that may enhance recovery in response to the physiological stress imposed by the process of surgery.

NEW & NOTEWORTHY

This study provides novel insight into the process by which surgical injury places the intestinal epithelium at risk for colonization by pathogenic microbes and impairment of its regenerative capacity via loss of its microbiota. We show that fecal transplant restores crypt homeostasis in association with repopulation of the microbiota within cecal crypts.

The role of cancer stem cells in tumor heterogeneity and resistance to therapy

Cancer is a heterogenous disease displaying marked inter- and intra-tumoral diversity. The existence of cancer stem cells (CSCs) has been experimentally demonstrated in a number of cancer types as a subpopulation of tumor cells that drives the tumorigenic and metastatic properties of the entire cancer. Thus, eradication of the CSC population is critical for the complete ablation of a tumor. This is, however, confounded by the inherent resistance of CSCs to standard anticancer therapies, eventually leading to the outgrowth of resistant tumor cells and relapse in patients. The cellular mechanisms of therapy resistance in CSCs are ascribed to several factors including a state of quiescence, an enhanced DNA damage response and active repair mechanisms, up-regulated expression of drug efflux transporters, as well as the activation of pro-survival signaling pathways and inactivation of apoptotic signaling. Understanding the mechanisms underlying the acquisition of resistance to therapy may hold the key to targeting the CSC population.

Current understanding concerning intestinal stem cells

In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same.

LGR5 is associated with tumor aggressiveness in papillary thyroid cancer

PURPOSE

Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a cancer stem cell marker and a down-stream target in Wnt/β-catenin signaling. In human papillary thyroid cancer (PTC), over activation of Wnt/β-catenin has been associated with tumor aggressiveness.

PATIENTS AND METHODS

Using established human cell lines (TPC-1, KTC-1, Nthy-ori-3–1), we report LGR5 and R-spondin (RSPO1–3) overexpression in PTC and manipulate LGR5 and Wnt/β-catenin signaling via both pharmacologic and genetic interventions. We test the association of LGR5 tumor expression with markers of PTC aggressiveness using a Discovery Cohort (n = 26 patients) and a Validation Cohort (n = 157 patients). Lastly, we explore the association between LGR5 and the BRAFV600E mutation (n = 33 patients).

RESULTS

Our results reveal that LGR5 and its ligand, RSPO, are overexpressed in human PTC, whereby Wnt/β-catenin signaling regulates LGR5 expression and promotes cellular migration. In two separate cohorts of patients, LGR5 and RSPO2 were associated with markers of tumor aggressiveness including: lymph node metastases, vascular invasion, increased tumor size, aggressive histology, advanced AJCC TNM stage, microscopic extra thyroidal extension, capsular invasion, and macroscopic invasion. As a biomarker, LGR5 positivity predicts lymph node metastasis with 95.5% sensitivity (95% CI 88.8%-98.7%) and 61% specificity (95% CI: 48.4%–72.4%) and has a negative predictive value (NPV) of 91.3% (95% CI 79.2%–97.5%) for lymph node metastatic disease. In human PTC, LGR5 is also strongly associated with the BRAFV600E mutation (p = 0.005).

CONCLUSION

We conclude that overexpression of LGR5 is associated with markers of tumor aggressiveness in human PTC. LGR5 may serve as a future potential biomarker for patient risk stratification and loco regional metastases in PTC.

Lgr5 expression is a valuable prognostic factor for colorectal cancer: evidence from a meta-analysis

Background

Lgr5 has recently been identified as a reliable biomarker of cancer stem cells (CSCs) in colorectal cancer (CRC); however, its prognostic value is still controversial.

Methods

We searched PubMed, Web of Science, and Wanfang databases with identical strategies to retrieve articles. We evaluated the impact of Lgr5 expression on survival of CRC patients through meta-analysis.

Results

A total of 12 studies comprising 2600 patients revealed that Lgr5 overexpression was negatively associated with overall survival (OS) (HR = 1.73, 95 % CI: 1.28–2.33; P = 0.00) and disease free survival (DFS) (HR = 2.89, 95 % CI: 1.89–4.44; P = 0.000) in CRC patients. Subgroup analysis suggested that Lgr5 overexpression was significantly associated with worse OS in subgroups with IHC as the method of Lgr5 assessment (HR = 2.01, 95 % CI: 1.39–2.89; P = 0.001), patients from Asia (HR = 1.81, 95 % CI: 1.27–2.58; P = 0.000), and NOS scores greater than 6 (HR = 2.12, 95 % CI: 1.41–3.19; P = 0.000). Furthermore, sensitivity analysis showed that the estimated HR ranged from 1.6 to 1.86 upon excluding one study sequentially from each analysis. In addition, Lgr5 overexpression was significantly associated with deep invasion of CRC (OR = 0.39, 95 % CI: 0.17–0.87; P = 0.002), lymphnode metastasis (OR = 0.45, 95 % CI: 0.26–0.76; P = 0.003), distant metastasis (OR = 0.37, 95 % CI: 0.22–0.62; P = 0.000), and AJCC stage (OR = 0.35, 95 % CI: 0.15–0.78; P = 0.01). However, Lgr5 overexpression was not correlated with tumor grade (OR = 0.75 95 % CI: 0.37–1.54; P = 0.433).

Conclusions

This study shows that Lgr5 can be a valuable and reliable prognostic factor of colorectal cancer progression.

Lgr5 expression is a valuable prognostic factor for colorectal cancer: evidence from a meta-analysis

Background

Lgr5 has recently been identified as a reliable biomarker of cancer stem cells (CSCs) in colorectal cancer (CRC); however, its prognostic value is still controversial.

Methods

We searched PubMed, Web of Science, and Wanfang databases with identical strategies to retrieve articles. We evaluated the impact of Lgr5 expression on survival of CRC patients through meta-analysis.

Results

A total of 12 studies comprising 2600 patients revealed that Lgr5 overexpression was negatively associated with overall survival (OS) (HR = 1.73, 95 % CI: 1.28–2.33; P = 0.00) and disease free survival (DFS) (HR = 2.89, 95 % CI: 1.89–4.44; P = 0.000) in CRC patients. Subgroup analysis suggested that Lgr5 overexpression was significantly associated with worse OS in subgroups with IHC as the method of Lgr5 assessment (HR = 2.01, 95 % CI: 1.39–2.89; P = 0.001), patients from Asia (HR = 1.81, 95 % CI: 1.27–2.58; P = 0.000), and NOS scores greater than 6 (HR = 2.12, 95 % CI: 1.41–3.19; P = 0.000). Furthermore, sensitivity analysis showed that the estimated HR ranged from 1.6 to 1.86 upon excluding one study sequentially from each analysis. In addition, Lgr5 overexpression was significantly associated with deep invasion of CRC (OR = 0.39, 95 % CI: 0.17–0.87; P = 0.002), lymphnode metastasis (OR = 0.45, 95 % CI: 0.26–0.76; P = 0.003), distant metastasis (OR = 0.37, 95 % CI: 0.22–0.62; P = 0.000), and AJCC stage (OR = 0.35, 95 % CI: 0.15–0.78; P = 0.01). However, Lgr5 overexpression was not correlated with tumor grade (OR = 0.75 95 % CI: 0.37–1.54; P = 0.433).

Conclusions

This study shows that Lgr5 can be a valuable and reliable prognostic factor of colorectal cancer progression.

Lgr5 Methylation in Cancer Stem Cell Differentiation and Prognosis-Prediction in Colorectal Cancer

OBJECTIVE

Leucine-rich-repeat-containing G-protein-coupled receptor 5 (lgr5) is a candidate marker for colorectal cancer stem cells (CSC). In the current study, we investigated the methylation status within thelgr5 promoter and evaluated its relationship with CSC differentiation, prognosis for colorectal cancer, and its clinicopathological features.

METHODS

The methylation status within Lgr5 promoter was detected with a methylation-specific PCR in six colorectal cancer cell lines as well as 169 primary colorectal tumor tissues. Differentiation of CSC was examined with immunofluorescence and immunocytochemistry. Down-regulation of lgr5 was achieved with gene-specific siRNA. The associations between lgr5 methylation and the clinicopathological features as well as survival of patients were analyzed with statistical methods.

RESULTS

The lgr5 promoter was methylated to different degrees for the six colorectal cell lines examined, with complete methylation observed in HCT116 cells in which the lgr5 expression was partially recovered following DAC treatment. The stem-cell sphere formation from HCT116 cells was accompanied by increasing methylation within the lgr5 promoter and decreasing expression of lgr5. Knocking down lgr5 by siRNA also led to stem-cell spheres formation. Among primary colorectal tumors, 40% (67/169) were positive for lgr5 methylation, while none of the normal colon tissues were positive for lgr5 methylation. Furthermore, lgr5 methylation significantly associated with higher tumor grade, and negative distant metastasis (p < 0.05), as well as better prognosis (p = 0.001) in patients with colorectal cancer.

CONCLUSIONS

Our data suggests that lgr5 methylation, through the regulation of lgr5 expression and colorectal CSC differentiation, may constitute a novel prognostic marker for colorectal cancer patients.

A conditional transgenic mouse line for targeted expression of the stem cell marker LGR5

LGR5 is a known marker of embryonic and adult stem cells in several tissues. In a mouse model, Lgr5+ cells have shown tumour-initiating properties, while in human cancers, such as basal cell carcinoma and colon cancer, LGR5 expression levels are increased: however, the effect of increased LGR5 expression is not fully understood. To study the effects of elevated LGR5 expression levels we generated a novel tetracycline-responsive, conditional transgenic mouse line expressing human LGR5, designated TRELGR5. In this transgenic line, LGR5 expression can be induced in any tissue depending on the expression pattern of the chosen transcriptional regulator. For the current study, we used transgenic mice with a tetracycline-regulated transcriptional transactivator linked to the bovine keratin 5 promoter (K5tTA) to drive expression of LGR5 in the epidermis. As expected, expression of human LGR5 was induced in the skin of double transgenic mice (K5tTA;TRELGR5). Inducing LGR5 expression during embryogenesis and early development resulted in macroscopically and microscopically detectable phenotypic changes, including kink tail, sparse fur coat and enlarged sebaceous glands. The fur and sebaceous gland phenotypes were reversible upon discontinued expression of transgenic LGR5, but this was not observed for the kink tail phenotype. There were no apparent phenotypic changes if LGR5 expression was induced at three weeks of age. The results demonstrate that increased expression of LGR5 during embryogenesis and the neonatal period alter skin development and homeostasis.

LGR5, a relevant marker of cancer stem cells, indicates a poor prognosis in colorectal cancer patients: a meta-analysis

BACKGROUND

Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) has been identified as a putative intestinal stem cell marker. However, the clinical prognosis of Lgr5 is still controversial in colorectal cancer (CRC). To systematically summarize the clinical prognostic function of Lgr5 in colorectal cancer, we performed this meta-analysis.

METHODS

Published articles which assessed the clinical or prognostic role of Lgr5 was searched in Pubmed, Embase and Springer and collected until the publication month of February 2014. The association of Lgr5 expression with clinical outcomes was investigated by a meta- analysis.

RESULTS

A total of 8 studies have been up to the inclusion standard, comprised 2139 patients. Lgr5 showed no relationship with the gender of patients (OR=0.919, 95% CI=0.730-1.157, P=0.473) and the depth of invasion (OR=2.616, CI 95%=0.947-7.221, P=0.063). Lgr5 was significantly associated with lymph node metastasis (OR=2.248, 95%CI=1.205-4.192, P=0.011), tumor distance metastasis (OR=3.872, 95%CI=2.792-5.370, P<0.001) and classification of TNM (pooled OR=3.264, 95% CI=1.731-6.155, P<0.001). Overall, overexpression of Lgr5 was statistically related to the reduced overall survival (HR=6.130, 95% CI=2.845-13.210, P<0.001).

CONCLUSIONS

Lgr5 participates in the progression of CRC as a putative factor. Overexpression of Lgr5 was distinctly correlated with poor patient survival. These findings suggested that Lgr5 might serve as an efficient biomarker for prognostic indicator, and could be a new molecular target in colorectal cancer therapy.

Rab27b is a potential predictor for metastasis and prognosis in colorectal cancer

Objective. Rab27b is reported to correlate with cancer development and progression. However, the association between Rab27b expression and the clinical characteristics of colorectal cancer (CRC) is barely investigated. Methods. One-step quantitative reverse transcription-polymerase chain reaction (qPCR) test with 18 fresh-frozen CRC samples and immunohistochemistry (IHC) analysis in 113 CRC cases were performed to explore the relationship between Rab27b expression and the clinicopathological features of CRC. Cox regression and Kaplan-Meier survival analyses were executed to evaluate the prognosis of CRC. Results. The results demonstrated that the expression levels of Rab27b mRNA and protein were significantly higher in CRC tissues than that in matched noncancerous tissues (P < 0.05). Rab27b protein expression in CRC was statistically correlated with serum CEA level (P = 0.004), lymph node metastasis (P = 0.001), distant metastasis (P = 0.009), and TNM stage (P = 0.001). Cox multifactor analysis and Kaplan-Meier method suggested that higher Rab27b protein expression (P = 0.041) and tumor differentiation (P = 0.001) were significantly associated with the overall survival of CRC patients. Conclusions. The data indicated that higher expression of Rab27b was observed in CRC tissues and Rab27b may be identified as a useful predictor of metastasis and prognosis for CRC.

MicroRNA-100 functions as a tumor suppressor by inhibiting Lgr5 expression in colon cancer cells

Previous studies have demonstrated that microRNAs (miRNAs), a class of single‑stranded RNA molecules that are 18‑27 nucleotides in length, serve a critical function in tumorigenesis, including in the development of colon cancer. In the current study, miR‑100 levels were demonstrated to be reduced in colon cancer tissues compared with the levels in matched adjacent normal tissues. Forced overexpression of miR‑100 by transfection with miR‑100 mimics substantially inhibited the proliferation, migration and invasion of SW480 and HCT116 cells, whereas reduced expression, resulting from transfection of antisense oligonucleotides, promoted these processes. At the molecular level, miR‑100 was observed to reduce the levels of leucine‑rich repeat‑containing G protein‑coupled receptor 5 (Lgr5), by binding to its 3'‑untranslated region. As a result of this, Wnt/β‑catenin signaling was affected by fluctuations in the level of miR‑100 mimics or antisense. Collectively, the results of the current study elucidate a novel regulatory pathway involving miR‑100 and Lgr5 in colon cancer cells, which may present a potential therapeutic target.

Prognostic value of LGR5 in colorectal cancer: a meta-analysis

Objective

Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) has recently been reported to be a marker of cancer stem cells (CSCs) in colorectal cancer (CRC), and the prognostic value of LGR5 in CRC has been evaluated in several studies. However, the conclusions remain controversial. In this study, we aimed to evaluate the association between the expression of LGR5 and the outcome of CRC patients by performing a meta-analysis.

Methods

We systematically searched for relevant studies published up to February 2014 using the PubMed, Web of Science, EMBASE and Wangfang databases. Only articles in which LGR5 expression was detected by immunohistochemistry were included. A meta-analysis was performed using STATA 12.0, and pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the strength of the association between LGR5 expression and the prognosis of CRC patients.

Results

A total of 7 studies comprising 1833 CRC patients met the inclusion criteria, including 6 studies comprising 1781 patients for overall survival (OS) and 3 studies comprising 528 patients for disease-free survival (DFS). Our results showed that high LGR5 expression was significantly associated with poor prognosis in terms of OS (HR: 1.87, 95% CI: 1.23–2.84; P = 0.003) and DFS (HR: 2.44, 95% CI: 1.49–3.98; P<0.001). Further subgroup analysis revealed that many factors, including the study region, number of patients, follow-up duration and cutoff value, affected the significance of the association between LGR5 expression and a worse prognosis in patients with CRC. In addition, there was no evidence of publication bias, as suggested by Begg’s and Egger’s tests.

Conclusions

The present meta-analysis indicated that high LGR5 expression was associated with poor prognosis in patients with CRC and that LGR5 is an efficient prognostic factor in CRC.