Lgr5 is a potential marker of colorectal carcinoma stem cells that correlates with patient survival

Impact of enzymatic isolation on the propagation efficiency of patient-derived colorectal cancer organoids

Cancer organoids are three-dimensional in vitro models that closely replicate the genetic, phenotypic, and heterogeneity characteristics of original tumors, making them valuable tools in cancer research. However, the lack of standardized protocols limits their broader application. This study evaluates the role of enzymatic isolation in generating patient-derived organoids (PDOs) from colorectal cancer tissues by comparing four enzymatic methods: TrypLE, Trypsin-EDTA (T/E), Collagenase, and Hyaluronidase. Colorectal cancer tissues were processed using these enzymes, and cell viability, dissociation efficiency, and isolation quality were assessed via Trypan Blue exclusion assay and 7-AAD staining with flow cytometry. Cancer stem cells marked by LGR5 and CD133 were quantified via flow cytometry, while organoid generation and growth were monitored over 11 days using confocal microscopy. TrypLE and T/E demonstrated superior preservation of cell viability but limited dissociation efficiency, yielding lower cell count per milligram of tissue. In contrast, Collagenase and Hyaluronidase demonstrated superior tissue dissociation, yielding higher total cell counts and the highest proportions of LGR5positive and CD133positive stem cell populations. Collagenase produced the highest organoid counts, while Hyaluronidase supported the largest organoid expansion, with both enzymes generating larger organoid surface areas and a greater number of organoids compared to TrypLE and T/E. These results highlight Collagenase and Hyaluronidase as optimal choices for PDO generation, providing a framework for optimizing dissociation protocols. This study underscores the critical influence of enzymatic dissociation methods on the establishment and reliability of colorectal cancer patient-derived organoids, providing a foundation for optimizing PDO protocols and advancing their translational application in precision oncology.

Oncogenic KRAS Mutations Confer a Unique Mechanotransduction Response to Peristalsis in Colorectal Cancer Cells

Colorectal cancer tumors start as polyps on the inner lining of the colorectum, in which they are exposed to the mechanics of peristalsis. Our previous work leveraged a custom-built peristalsis bioreactor to demonstrate that colonic peristalsis led to cancer stem cell enrichment in colorectal cancer cells. However, this malignant mechanotransductive response was confined to select colorectal cancer lines that harbored an oncogenic mutation in the Kirsten rat sarcoma virus (KRAS) gene. In this study, we explored the involvement of activating KRAS mutations on peristalsis-associated mechanotransduction in colorectal cancer. Peristalsis enriched cancer stem cell marker Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) in KRAS mutant lines in a Wnt ligand-independent manner. Conversely, LGR5 enrichment in wild-type KRAS lines exposed to peristalsis were minimal. LGR5 enrichment downstream of peristalsis translated to increased tumorigenicity in vivo. Differences in mechanotransduction were apparent via unbiased gene set enrichment analysis, in which many unique pathways were enriched in wild-type versus mutant lines. Peristalsis also triggered β-catenin nuclear localization independent of Wnt ligands, particularly in KRAS mutant lines. The involvement of KRAS was validated via gain and loss of function strategies. Peristalsis-induced β-catenin activation and LGR5 enrichment depended on the activation of the MEK/ERK cascade. Taken together, our results demonstrated that oncogenic KRAS mutations conferred a unique peristalsis-associated mechanotransduction response to colorectal cancer cells, resulting in cancer stem cell enrichment and increased tumorigenicity. These mechanosensory connections can be leveraged in improving the sensitivity of emerging therapies that target oncogenic KRAS. Implications: Oncogenic KRAS empowers colorectal cancer cells to harness the mechanics of colonic peristalsis for malignant gain independent of other cooperating signals.

LGR5: An emerging therapeutic target for cancer metastasis and chemotherapy resistance

Cancer stem cells play an important role in tumor progression and chemotherapy resistance. Leucine-rich G repeat-containing protein-coupled receptor 5 (LGR5) has been identified as a cancer stem cell marker in several cancer types. LGR5 is involved in cancer development and progression via several pathways including WNT/β-catenin signaling pathway. LGR5 plays a role in tumor progression by promoting cancer cell migration, invasion, metastasis, and angiogenesis in many cancers including colorectal, brain, gastric, and ovarian cancer. This review summarises the current knowledge on the expression and functional role of LGR5 in cancers, the molecular mechanisms regulated by LGR5, and the relationship between LGR5 and chemotherapy resistance. The review also includes highlights potential strategies to inhibit LGR5 expression and function. The majority of functional studies have shown that LGR5 plays an important role in promoting cancer progression, metastasis and chemotherapy resistance however, in some contexts LGR5 can also activate tumor-suppressive pathways and LGR5 negative cells can also promote cancer progression. The review highlights that targeting LGR5 is a promising anti-cancer treatment but the functional effect of LGR5 on tumor cells is complex may be dependent on cancer type, tumor microenvironment and cross-talk with other molecules in the LGR5 signaling pathway.

Role of Leucine-Rich Repeat-Containing G-Protein-Coupled Receptors 4-6 (LGR4-6) in the Ovary and Other Female Reproductive Organs: A Literature Review

Leucine-rich repeat-containing G-protein-coupled receptors regulate stem cell activity and tissue homeostasis within female reproductive organs, primarily through their interaction with the Wnt/β-catenin signaling pathway. LGR4-6 are increasingly recognized for their roles in organ development, regeneration, and cancer. This review aims to provide a comprehensive overview of the roles of LGR4-6 in female reproductive organs, highlighting their significance in normal physiology and disease states, specifically in the context of ovarian cancer. LGR4 is essential for the proper development of the female reproductive system; its deficiency leads to significant reproductive abnormalities, including delayed menarche and follicle development issues. LGR5 is a well-established marker of stem cells in the ovary and fallopian tubes. It has been implicated in the pathogenesis of high-grade serous ovarian cancer. LGR6, while less studied, shares functional similarities with LGR5 and can maintain stemness. It contributes to chemoresistance in ovarian cancer. LGR6 is a marker for fallopian tube stem cells and is involved in stem cell maintenance and differentiation. LGR4-6 regulate the pathophysiology of female reproductive tissues. LGR4-6 are promising therapeutic targets for treating reproductive cancers and other related disorders. Molecular mechanisms underlying the functions of LGR4-6 should be studied.

Rectal Epithelial Stem Cell Kinetics in Acute Radiation Proctitis

The intestinal tract is a typical radiosensitive tissue, and radiation rectal injury is a severe side effect that limits the prescribed dose in radiotherapy of the abdominal and pelvic region. Understanding the post-irradiation kinetics of Lgr5-positive stem cells is crucial in comprehending this adverse process. In this study, we utilized Lgr5-EGFP knock-in mice expressing EGFP and LGR5 antibody fluorescence staining of wild-type mice. At the state of radiation injury, the qPCR analysis showed a significant decrease in the expression level of Lgr5 in the rectal epithelial tissue. The dose-response relationship analysis showed that at low to moderate doses up to 10 gray (Gy), Lgr5-clustered populations were observed at the base of the crypt, whereas at sublethal doses (20 Gy and 29 Gy), the cells exhibited a dot-like scatter pattern, termed Lgr5-dotted populations. During recovery, 30 days post-irradiation, Lgr5-clustered populations gradually re-emerged while Lgr5-dotted populations declined, implying that some of the Lgr5-dotted stem cell populations re-clustered, aiding regenerations. Based on statistical analysis of the dose-response relationship using wild-type mice, the threshold dose for destroying these stem cell structures is 18 Gy. These findings may help set doses in mouse abdominal irradiation experiments for radiation intestinal injury and for understanding the histological process of injury development.

Leucine-rich repeat-containing G protein-coupled receptor 5 expression in lymph node metastases of colorectal cancer: Clinicopathological insights and prognostic implications

Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), a significant cancer stem cell marker in colorectal cancer (CRC), lacks lymph node (LN) expression studies. In this study, we identified LGR5 expression by RNAscope, a highly sensitive RNA in situ method, and analyzed its association with clinicopathological characteristics. Tissue microarrays were generated from primary tumors (PTs) and LN metastases in paraffin-embedded blocks of 38 CRC surgical resection materials. LGR5 expression by RNAscope was evaluated by dividing the expression levels into negative and positive expression. In all but two cases of LN metastasis, LGR5-positive dots were detected in tumor cells, and there was a wide range of LGR5-positive cells. More LGR5-positive dots were identified in the gland-forming region. Twenty-three cases were classified into a high LGR5-expression group, and 15 cases were classified into a low LGR5-expression group. In the high LGR5-expression group, the histological grade was lower than in the low LGR5-expression group (p = 0.0159), while necrosis was significantly more prevalent (p = 0.0326), and the tumor, node, metastasis stage was significantly lower (p = 0.0302). There was no association between LGR5 expression levels in LN metastases and LGR5 expression levels in PT tissue. LGR5 expression in LN metastases may influence prognosis. Further analysis may lead to new therapeutic strategies.

Clinical Implications and Prognostic Value of Leucine-Rich G Protein-Coupled Receptor 5 Expression as A Cancer Stem Cell Marker in Malignancies: A Systematic Review and Meta-Analysis

Leucine-rich G protein-coupled receptor 5 (LGR5) is a marker of cancer stem cells (CSCs) in various cancers. Based on different studies, conflicting reports exist on correlation between LGR5 expression and poor prognosis/ clinicopathological parameters in cancer patients. Therefore, our purpose in conducting this study was to investigate correlation between LGR5 expression and outcomes of cancer patients under study through a systematic review and meta-analysis. Relevant articles were searched and collected using EMBASE, PubMed, Science Direct, and Scopus databases until December 21, 2022. This study was conducted to examine correlation between LGR5 expression and different clinical outcomes, such as recurrence-free survival (RFS), disease-free survival (DFS), overall survival (OS), and clinicopathological characteristics of the included cancer patients. To achieve this, hazard ratios (HRs) with 95% confidence intervals (CIs) and odds ratios (ORs) with 95% CIs were used as statistical measures. A meta-analysis was conducted using STATA 12.0 software. Finally, 53 studies including 9523 patients met the inclusion criteria. Significantly, high-level expression of LGR5 was related to poor prognosis in terms of OS, higher tumor stage, presence of distant metastasis, and presence of lymph node metastasis. It was discovered through subgroup analysis that several factors, including the study area, evaluation method, and type of cancer, can influence the correlation between LGR5 expression and negative prognosis in cancer patients. According to the results of our study, LGR5 overexpression was related to poor OS in cancer patients. In addition, clinicopathological data indicated an unfavorable prognosis in cancer patients with high LGR5 expression. In conclusion, LGR5 may serve as a potential prognostic marker for predicting survival in certain cancer types.

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.

Association between Ki67 expression and therapeutic outcome in colon cancer

Ki67 is a commonly used proliferation marker in pathological diagnosis of tumors; however, its prognostic value in colon cancer is controversial. A total of 312 consecutive patients with stage I-III colon cancer who underwent radical surgery with or without adjuvant chemotherapy were included in the present study. Ki67 expression was assessed using immunohistochemistry and was classified according to 25% intervals. The association between Ki67 expression and clinicopathological features was analyzed. Long-term postoperative survival, including disease-free survival (DFS) and overall survival, was calculated, and its association with Ki67 was analyzed. High Ki67 expression (>50%) was associated with improved DFS in patients treated with adjuvant chemotherapy postoperatively, but not in patients who received surgery alone (P=0.138). Ki67 expression was significantly associated with histological differentiation of the tumor (P=0.01), while it was not associated with other clinicopathological factors. Multivariate analysis demonstrated that pathological T and N stage were independent prognostic factors. In conclusion, high Ki67 expression was associated with a good therapeutic outcome in patients receiving adjuvant chemotherapy in colon cancer.

3D bioprinted colorectal cancer models based on hyaluronic acid and signalling glycans

In cancer microenvironment, aberrant glycosylation events of ECM proteins and cell surface receptors occur. We developed a protocol to generate 3D bioprinted models of colorectal cancer (CRC) crosslinking hyaluronic acid and gelatin functionalized with three signalling glycans characterized in CRC, 3'-Sialylgalactose, 6'-Sialylgalactose and 2'-Fucosylgalactose. The crosslinking, performed exploiting azide functionalized gelatin and hyaluronic acid and 4arm-PEG-dibenzocyclooctyne, resulted in biocompatible hydrogels that were 3D bioprinted with commercial CRC cells HT-29 and patient derived CRC tumoroids. The glycosylated hydrogels showed good 3D printability, biocompatibility and stability over the time. SEM and synchrotron radiation SAXS/WAXS analysis revealed the influence of glycosylation in the construct morphology, whereas MALDI-MS imaging showed that protein profiles of tumoroid cells vary with glycosylation, indicating that sialylation and fucosylation of ECM proteins induce diverse alterations to the proteome of the tumoroid and surrounding cells.

The importance of CA 72-4 and CA 19-9 dosing in gastric cancer

Serological analysis of tumor markers has emerged as a non-invasive method for monitoring cancer patients, including tumor recurrence and response to treatment. Tumor markers have the potential to aid in both the diagnosis and prognosis of cancer, but their most important role currently lies in the monitoring of tumor progression. Tumor markers can also provide valuable information on treatment effectiveness, with changes in plasma values indicating tumor regression or progression. This research aimed to investigate the correlation between the serum detection values of three tumor markers - CEA, CA 19-9, and CA 72-4 - and their utility in the diagnosis and prognosis of patients with gastric cancer. The study seeks to uncover the relationship between these tumor markers and the evolution of gastric cancer, providing insights into their potential use in clinical practice.

Over-Expression of ARID3B Suppresses Tumor Progression and Predicts Better Prognosis in Patients With Gastric Cancer

BACKGROUND

ARID3B (AT-rich interaction domain 3B) has been demonstrated to be associated with the progression and patient prognosis of several human tumors. We conducted the present study to investigate the biological behavior and clinical relevance of ARID3B in gastric cancer (GC).

METHODS

Detection of the expression level in GC tissues and cell lines were performed by Western blot and immunohistochemistry. We also retrospectively analyzed the correlation of ARID3B with clinicopathological characteristics and patient prognosis in gastric cancer. The biological functions of ARID3B in GC cells were further explored by transwell migration assays, wound healing assays and cell proliferation assay.

RESULTS

The present study suggested that the expression of ARID3B was significantly lower in GC tissues than in adjacent normal tissues. IHC staining in tissues of 406 GC patients from training and validation sets verified that ARID3B over-expression correlated with clinicopathological features, such as degree of differentiation and clinical stage. Meanwhile, ARID3B was proved to be an independent prognostic factor for GC prognosis. Furthermore, over-expression of ARID3B suppressed proliferation in GC cells according CCK8 assay. We found that over-expression of ARID3B inhibited GC cell migration by transwell assay and wound healing assay. Furthermore, EMT markers were detected in ARID3B over-expression GC cells, which showed that ARID3B may inhibit metastasis of GC cells.

CONCLUSION

Our results firstly revealed that the expression level of ARID3B was closely correlated with clinicopathological features and may serve as an independent prognostic factor for GC patients. More importantly, ARID3B could suppress GC progression, including cell proliferation, migration and metastasis.

Cancer stem cell marker expression and methylation status in patients with colorectal cancer

The number of individuals diagnosed with colorectal cancer (CRC) has been on an alarming upward trajectory over the past decade. In some countries, this cancer represents one of the most frequently diagnosed types of neoplasia. Therefore, it is an important demand to study the pathology underlying this disease to gain insights into the mechanism of resistance to treatment. Resistance of tumors to chemotherapy and tumor aggressiveness have been associated with a minor population of neoplastic cells, which are considered to be responsible for tumor recurrence. These types of neoplastic cells are known as cancer stem cells, which have been previously reported to serve an important role in pathogenesis of this malignant disease. Slovakia has one of the highest incidence rates of CRC worldwide. In the present study, the aim was to classify the abundance of selected stem cell markers (CD133, CD166 and Lgr5) in CRC tumors using flow cytometry. In addition, the methylation status of selected genomic regions of CRC biomarkers (ADAMTS16, MGMT, PROM1 (CD133), LGR5 and ALCAM) was investigated by pyrosequencing in a cohort of patients from Martin University Hospital, Martin, Slovakia. Samples from both primary tumors and metastatic tumors were tested. Analysis of DNA methylation in the genomic regions of indicated five CRC biomarkers was also performed, which revealed the highest levels of methylation in the A disintegrin and metalloproteinase with thrombospondin motifs 16 and O6-methyguanine-DNA methyl transferase genes, whereas the lowest levels of methylation were found in genes expressing prominin-1, leucine-rich repeat-containing G-protein-coupled receptor 5 and activated leukocyte cell adhesion molecule. Furthermore, tumor tissues from metastases showed significantly higher levels of CD133⁺ cells compared with that in primary tumors. Higher levels of CD133⁺ cells correlated with TNM stage and the invasiveness of CRC into the lymphatic system. Although relatively small number of samples was processed, CD133 marker was consider to be important marker in pathology of CRC.

Significant co-expression of putative cancer stem cell markers, EpCAM and CD166, correlates with tumor stage and invasive behavior in colorectal cancer

BACKGROUND

The crucial oncogenic role of cancer stem cells (CSCs) in tumor maintenance, progression, drug resistance, and relapse has been clarified in different cancers, particularly in colorectal cancer (CRC). The current study was conducted to evaluate the co-expression pattern and clinical significance of epithelial cell adhesion molecules (EpCAM) and activated leukocyte cell adhesion (CD166 or ALCAM) in CRC patients.

METHODS

This study was carried out on 458 paraffin-embedded CRC specimens by immunohistochemistry on tissue microarray (TMA) slides.

RESULTS

Elevated expression of EpCAM and CD166 was observed in 61.5% (246/427) and 40.5% (164/405) of CRC cases. Our analysis showed a significant positive association of EpCAM expression with tumor size (P = 0.02), tumor stage (P = 0.007), tumor differentiate (P = 0.005), vascular (P = 0.01), neural (P = 0.01), and lymph node (P = 0.001) invasion. There were no significant differences between CD166 expression and clinicopathological parameters. Moreover, the combined analysis demonstrated a reciprocal significant correlation between EpCAM and CD166 expression (P = 0.02). Interestingly, there was a significant positive correlation between EpCAM/CD166 phenotypes expression and tumor stage (P = 0.03), tumor differentiation (P = 0.05), neural, and lymph node invasion (P =0.01).

CONCLUSIONS

The significant correlation of EpCAM and CD166 expression and their association with tumor progression and aggressive behavior is the reason for the suggestion of these two CSC markers as promising targets to promote novel effective targeted-therapy strategies for cancer treatment in the present study.

Clinical Significance of Stem Cell Biomarkers EpCAM, LGR5 and LGR4 mRNA Levels in Lymph Nodes of Colon Cancer Patients

The significance of cancer stem cells (CSCs) in initiation and progression of colon cancer (CC) has been established. In this study, we investigated the utility of measuring mRNA expression levels of CSC markers EpCAM, LGR5 and LGR4 for predicting survival outcome in surgically treated CC patients. Expression levels were determined in 5 CC cell lines, 66 primary CC tumors and 382 regional lymph nodes of 121 CC patients. Prognostic relevance was determined using Kaplan-Meier survival and Cox regression analyses. CC patients with lymph nodes expressing high levels of EpCAM, LGR5 or LGR4 (higher than a clinical cutoff of 0.07, 0.06 and 2.558 mRNA copies/18S rRNA unit, respectively) had a decreased mean survival time of 32 months for EpCAM and 42 months for both LGR5 and LGR4 at a 12-year follow-up (p = 0.022, p = 0.005 and p = 0.011, respectively). Additional patients at risk for recurrence were detected when LGR5 was combined with the biomarkers CXCL17 or CEA plus CXCL16. In conclusion, the study underscores LGR5 as a particularly useful prognostic biomarker and illustrates the strength of combining biomarkers detecting different subpopulations of cancer cells and/or cells in the tumor microenvironment for predicting recurrence.

Clinical Significance of Stem Cell Biomarkers EpCAM, LGR5 and LGR4 mRNA Levels in Lymph Nodes of Colon Cancer Patients

The significance of cancer stem cells (CSCs) in initiation and progression of colon cancer (CC) has been established. In this study, we investigated the utility of measuring mRNA expression levels of CSC markers EpCAM, LGR5 and LGR4 for predicting survival outcome in surgically treated CC patients. Expression levels were determined in 5 CC cell lines, 66 primary CC tumors and 382 regional lymph nodes of 121 CC patients. Prognostic relevance was determined using Kaplan-Meier survival and Cox regression analyses. CC patients with lymph nodes expressing high levels of EpCAM, LGR5 or LGR4 (higher than a clinical cutoff of 0.07, 0.06 and 2.558 mRNA copies/18S rRNA unit, respectively) had a decreased mean survival time of 32 months for EpCAM and 42 months for both LGR5 and LGR4 at a 12-year follow-up (p = 0.022, p = 0.005 and p = 0.011, respectively). Additional patients at risk for recurrence were detected when LGR5 was combined with the biomarkers CXCL17 or CEA plus CXCL16. In conclusion, the study underscores LGR5 as a particularly useful prognostic biomarker and illustrates the strength of combining biomarkers detecting different subpopulations of cancer cells and/or cells in the tumor microenvironment for predicting recurrence.

Inverse correlation between PD-L1 expression and LGR5 expression in tumor budding of stage II/III colorectal cancer

We investigated the expression of LGR5, the most robust and reliable known cancer stem cell (CSC) marker of colorectal cancer, and PD-L1 in tumor budding (TB), as well as clinicopathological features. Tissue microarrays (TMAs) were generated from TB samples from 32 stage II/III colorectal adenocarcinoma patients, and LGR5 expression in TMAs was evaluated by RNAscope, an extremely sensitive RNA in situ hybridization technique. LGR5 expression was significantly lower in the PD-L1-positive group than in the PD-L1-negative group (P = 0.0256). In the PD-L1-positive group, the tumor-infiltrating lymphocytes (TILs) score tended to be higher while the TNM stage was lower compared with the PD-L1 negative group (P = 0.0822 and P = 0.0765, respectively). There was no significant difference in Overall Survival between the PD-L1-positive and PD-L1-negative groups (log-rank test, P = 0.8218). This study showed that PD-L1-positive patients are a unique population with low LGR5 expression, and that LGR5-positive cells may be a promising therapeutic target in PD-L1-negative patients.

The Expression Analysis of Intestinal Cancer Stem Cell Marker Lgr5 in Colorectal Cancer Patients and the Correlation with Histopathological Markers

INTRODUCTION

Cancer stem cells (CSCs) have frequently been utilized in the cell characterization and identified responsible for tumor development, metastasis, recurrence, and chemoresistance. CSC surface markers function in cancer cell signaling and are indicated as potential biomarkers for cancer diagnosis and prognosis. As well, dysregulation of cancer-related signaling pathways could promote CSC development and progression. Our aim was to evaluate the expression of colorectal CSC markers and their correlation with cancer proliferation and angiogenesis.

METHODS

In this case-control study, total RNA was extracted from a total of 74 colorectal tumors and 74 adjacent normal tissue biopsies. Then, using a quantitative real-time PCR, the relative expression levels of Lgr5 and Lrig1 were measured in all malignant and healthy samples. Also, immunohistochemical (IHC) staining of tumor tissues was performed for Ki-67 (proliferation) and CD34 (angiogenesis) markers, and the immunoexpression staining scores were obtained. The diagnostic value of the genes was evaluated using receiver operating characteristic (ROC) curve. Possible correlation between CSC markers and immunohistochemical markers in CRC was analyzed by Pearson's correlation test and linear regression.

RESULTS

The expression level of Lgr5 in tumor samples showed a significant increase compared with normal samples (p < 0.001) with a fold change of 2.54 (± 0.182). However, there was no significant difference in the relative expression of Lrig1 gene in tissue samples of healthy subjects and patients. The analysis of the ROC showed an AUC of 0.92 for Lgr5 and sensitivity 80% and specificity 96%. Further analysis revealed a significant correlation between mRNA levels of Lgr5 and immunoexpression of Ki-67 (r² = 0.680, p < 0.001).

CONCLUSION

The high expression levels of Lgr5 found in tumor tissues were correlated with histological parameters, indicating a significant role in CRC development and diagnosis.

The role of tumor budding in colorectal adenocarcinoma: Possible involvement of the intestinal cancer stem cell marker Lgr5

Background

Tumor budding (TB) is a promising prognostic factor in colorectal cancer (CRC) that is independent of tumor-node-metastasis (TNM) staging. Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is a stem cell marker and a member of the canonical Wnt-signaling cascade. It is involved in colorectal carcinogenesis. However, its role in CRC progression and TB needs to be clarified.

Materials and Methods

TB was assessed in both H and E and CK immunostained sections of 92 CRC cases. Associations between TB grade and different clinicopathological parameters were evaluated. Lgr5 expression in CRC cases and its association with TB grade and other clinicopathological features was also evaluated.

Results

H and E stained sections revealed low- and high-grade budding in 55 (59.8%) and 37 (40.2%) tumors, respectively, whereas Cytokeratin Immunohistochemistry (CK-IHC) showed low- and high-grade budding in 31 (33.7%) and 61 (66.3%) tumors, respectively. TB grade (in H and E and CK stained sections) was significantly associated with adverse pathological prognostic variables including vascular invasion (P = 0.03 and 0.001), lymph node metastasis (P = 0.001 and 0,001), advanced Dukes (P = 0.000 and 0.000), and TNM (P = 0.001 and 0.000) stages and inversely associated with Tumor infiltrating lymphocytes (TILS) (P = 0.02 and 0.0001) which is known to be a good prognostic indicator. Lgr5 protein was positively expressed in 52.2% (48/92) of the CRCs. Immunoreactivity of Lgr5 was significantly associated with histological grade (P = 0.01), lymph node metastasis (P = 0.002), vascular invasion (P = 0.02), TNM stage (P = 0.000), Dukes stage (P = 0.000), and TILS (P = 0.03). Furthermore, Lgr5 was found to be significantly associated with TB estimated in both H and E and CK stained tumors (P = 0.003 and 0.001 respectively).

Conclusion

This study supported the relevance of TB in the assessment of CRC aggressiveness. It also revealed that Lgr5 expression is related to morphologic features in the invasive front of CRC. Lgr5 could have an important role in forming a morphologic feature at the invasive front associated with the aggressiveness of the tumor.

Correlation of clinicopathological features and LGR5 expression in colon adenocarcinoma

Colon cancer stem cells (CSCs) are closely related to tumorigenesis and treatment response, and LGR5 is currently the most robust and reliable CSC marker in colorectal cancer (CRC). However, LGR5 expression in CRC tumor budding (TB) is not well understood. We examined the clinicopathological and prognostic significance of LGR5 in CRC TB. LGR5 expression was evaluated by RNAscope, a newly developed RNA in situ hybridization technique, using a tissue microarray consisting of 55 patient samples of TB in colon adenocarcinoma (CA) selected from the medical archives at our hospital. Patients were stratified into negative and positive LGR5 expression groups. Tumor-infiltrating lymphocytes (TILs) and histological grade were lower in the LGR5-positive group compared with the LGR5-negative group (P = .0407 and P = .0436, respectively). There was no significant difference in overall survival between the LGR5-positive group and the LGR5-negative group (log-rank test, P = .6931). LGR5 expression did not remain a predictor of prognosis in univariate analysis (OR = 0.84, 95% CI: 0.33-2.02, P = .6928). LGR5 expression may be affected by TILs, which have been demonstrated to be associated with worse prognosis in the budding area of CA and is an important potential marker of prognosis.

Advancements in Cancer Stem Cell Isolation and Characterization

Occurrence of stem cells (CSCs) in cancer is well established in last two decades. These rare cells share several properties including presence of common surface markers, stem cell markers, chemo- and radio- resistance and are highly metastatic in nature; thus, considered as valuable prognostic and therapeutic targets in cancer. However, the studies related to CSCs pave number of issues due to rare cell population and difficulties in their isolation ascribed to common stem cell marker. Various techniques including flow cytometry, laser micro-dissection, fluorescent nanodiamonds and microfluidics are used for the isolation of these rare cells. In this review, we have included the advance strategies adopted for the isolation of CSCs using above mentioned techniques. Furthermore, CSCs are primarily found in the core of the solid tumors and their microenvironment plays an important role in maintenance, self-renewal, division and tumor development. Therefore, in vivo tracking and model development become obligatory for functional studies of CSCs. Fluorescence and bioluminescence tagging has been widely used for transplantation assay and lineage tracking experiments to improve our understanding towards CSCs behaviour in their niche. Techniques such as Magnetic resonance imaging (MRI) and Positron emission tomography (PET) have proved useful for tracking of endogenous CSCs which could be helpful in their identification in clinical settings.

The prognostic value of leucine-rich repeat-containing G-protein (Lgr5) and its impact on clinicopathological features of colorectal cancer

Introduction

Colorectal cancer (CRC) constitutes one of the most prevalent malignancies in the world. Recent research suggests that cancer stem cells (CSCs) are responsible for tumor cell’s malignant behavior in CRC. This study has been designed to determinate clinical implications of CSC markers: CD44, DCLK1, Lgr5, and ANXA2 in CRC.

Materials and methods

The study was performed on tissue samples which were collected from 89 patients undergoing colectomy. Formalin-fixed paraffin-embedded tissue blocks with representative tumor areas were identified and corded. Immunohistochemical staining was performed using anti-CD44, anti-LGR5, anti-ANXA2, and anti-DCLK1 antibodies. The H-score system was utilized to determine the immunointensity of CRC cells.

Results

The lower expression of Lgr5 was significantly correlated with the presence of lymph-node metastases (p = 0.011), while high expression of Lgr5 was statistically significant in vascular invasion in examined cancer tissue samples (p = 0.027). Moreover, a high H-score value of Lgr5 expression was significantly related to a reduced overall survival rate (p = 0.043).

Conclusion

Our results suggest a strong relationship between CSC marker Lgr5 and vascular invasion, presence of lymph-node metastasis, and overall poor survival. The presence of Lgr5 might be an unfavorable prognostic factor, and its high level in cancer tissue is related to an aggressive course. This marker could also be used to access the effectiveness of the treatment.

Characterization of LGR5 expression in poorly differentiated colorectal carcinoma with mismatch repair protein deficiency

BACKGROUND

Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a promising intestinal stem cell and carcinoma stem cell marker. We examined the relationship between mismatch repair (MMR) protein deficiency and LGR5 expression in poorly differentiated (PD) colorectal carcinoma (CRC).

METHODS

In 29 cases of PD-CRC, deficiencies in MMR proteins (MLH1, PMS2, MSH2, MSH6) and β-catenin expression were identified by immunohistochemistry (IHC). LGR5 expression was examined by the RNAscope assay in tissue microarrays.

RESULTS

LGR5 H-scores in MMR-deficient (MMR-D) cases were significantly lower than those in MMR-proficient (MMR-P) cases (P = 0.0033). Nuclear β-catenin IHC scores in MMR-D cases were significantly lower than those in MMR-P cases (P = 0.0024). In all cases, there was a positive correlation between LGR5 H-score and nuclear β-catenin IHC score (r = 0.6796, P < 0.001). Even in MMR-D and MMR-P cases, there was a positive correlation between LGR5 H-score and nuclear β-catenin IHC score (r = 0.7180, P < 0.0085 and r = 0.6574, P < 0.003, respectively). MMR-D CRC cases showed low expression of LGR5, which may be due to low activation of the Wnt/β-catenin signaling pathway.

CONCLUSIONS

Our results reveal the relationship between LGR5 expression and MMR protein profiles in PD-CRC. A further study is warranted to confirm these findings.

Characterization of iPS87, a prostate cancer stem cell-like cell line

Prostate cancer affects hundreds of thousands of men and families throughout the world. Although chemotherapy, radiation, surgery, and androgen deprivation therapy are applied, these therapies do not cure metastatic prostate cancer. Patients treated by androgen deprivation often develop castration resistant prostate cancer which is incurable. Novel approaches of treatment are clearly necessary. We have previously shown that prostate cancer originates as a stem cell disease. A prostate cancer patient sample, #87, obtained from prostatectomy surgery, was collected and frozen as single cell suspension. Cancer stem cell cultures were grown, single cell-cloned, and shown to be tumorigenic in SCID mice. However, outside its natural niche, the cultured prostate cancer stem cells lost their tumor-inducing capability and stem cell marker expression after approximately 8 transfers at a 1:3 split ratio. Tumor-inducing activity could be restored by inducing the cells to pluripotency using the method of Yamanaka. Cultures of human prostate-derived normal epithelial cells acquired from commercial sources were similarly induced to pluripotency and these did not acquire a tumor phenotype in vivo. To characterize the iPS87 cell line, cells were stained with antibodies to various markers of stem cells including: ALDH7A1, LGR5, Oct4, Nanog, Sox2, Androgen Receptor, and Retinoid X Receptor. These markers were found to be expressed by iPS87 cells, and the high tumorigenicity in SCID mice of iPS87 was confirmed by histopathology. This research thus characterizes the iPS87 cell line as a cancer-inducing, stem cell-like cell line, which can be used in the development of novel treatments for prostate cancer.

Clinicopathologic and prognostic significance of LGR5, a cancer stem cell marker in patients with colorectal cancer

Aim:

To analyze the clinicopathologic and prognostic significance of Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a cancer stem cell marker expression in a cohort of colorectal cancer patients (CRC).

Patients & methods:

A total of 76 formalin-fixed paraffin-embedded tissue blocks of primary or metastatic tumors from 49 CRC patients were collected for duration 2009–2015. LGR5 expression was assessed through immunohistochemical staining of a tissue microarray.

Results:

LGR5 was significantly over expressed in CRC tissue samples and found to be a statistically significant independent prognostic marker for an improved overall survival.

Conclusion:

LGR5 expression was higher in colorectal cancer than in normal tissue. LGR5 was an independent prognostic marker for better clinical outcomes and might be used as a potential therapeutic target in CRCs.

The Pivotal Role of Long Noncoding RNA RAB5IF in the Proliferation of Hepatocellular Carcinoma Via LGR5 Mediated β-Catenin and c-Myc Signaling

In the current study, the function of long noncoding RNA (LncRNA) RAB5IF was elucidated in hepatocellular carcinoma (HCCs) in association with LGR5 related signaling. Here TCGA analysis revealed that LncRNA RAB5IF was overexpressed in HCC, and its overexpression level was significantly (p < 0.05) correlated with poor prognosis in patients with HCC. Furthermore, LncRNA RAB5IF depletion suppressed cell proliferation and colony formation, increased sub G1 population, cleavage of poly ADP-ribose polymerase (PARP) and cysteine aspartyl-specific protease (caspase 3) and attenuated the expression of procaspase 3, pro-PARP and B-cell lymphoma 2 (Bcl-2) in HepG2 and Hep3B cells. Furthermore, LncRNA RAB5IF depletion reduced the expression of LGR5 and its downstreams such as β-catenin and c-Myc in HepG2 and Hep3B cells. Notably, LGR5 depletion also attenuated the expression of pro-PARP, pro-caspase3, β-catenin and c-Myc in HepG2 and Hep3B cells. Conversely, LGR5 overexpression upregulated β-catenin and c-Myc in Alpha Mouse Liver 12 (AML-12) normal hepatocytes. Overall, these findings provide novel evidence that LncRNA RAB5IF promotes the growth of hepatocellular carcinoma cells via LGR5 mediated β-catenin and c-Myc signaling as a potent oncogenic target.

Targeting transcription factor TCF4 by γ-Mangostin, a natural xanthone

Given that colon cancer is the third most common cancer in incidence and cause of death in the United States, and current treatment modalities are insufficient, there is a need to develop novel agents. Towards this, here we focus on γ-Mangostin, a bioactive compound present in the Mangosteen (Garcinia mangostana) fruit. γ-Mangostin suppressed proliferation and colony formation, and induced cell cycle arrest and apoptosis of colon cancer cell lines. Further, γ-Mangostin inhibited colonosphere formation. Molecular docking and CETSA (Cellular thermal shift assay) binding assays demonstrated that γ-Mangostin interacts with transcription factor TCF4 (T-Cell Factor 4) at the β-catenin binding domain with the binding energy of -5.5 Kcal/mol. Moreover, γ-Mangostin treatment decreased TCF4 expression and reduced TCF reporter activity. The compound also suppressed the expression of Wnt signaling target proteins cyclin D1 and c-Myc, and stem cell markers such as LGR5, DCLK1 and CD44. To determine the effect of γ-Mangostin on tumor growth in vivo, we administered nude mice harboring HCT116 tumor xenografts with 5 mg/Kg of γ-Mangostin intraperitoneally for 21 days. γ-Mangostin treatment significantly suppressed tumor growth, with notably lowered tumor volume and weight. In addition, western blot analysis revealed a significant decrease in the expression of TCF4 and its downstream targets such as cyclin D1 and c-Myc. Together, these data suggest that γ-Mangostin inhibits colon cancer growth through targeting TCF4. γ-Mangostin may be a potential therapeutic agent for colon cancer.

Regulatory mechanisms of microRNAs in colorectal cancer and colorectal cancer stem cells

Colorectal cancer (CRC) is one of the most lethal and hard-to-treat cancers in the world, which in its advanced stages, surgery and chemotherapy are the main common treatment approaches. The microRNAs (miRNAs), as novel markers for CRC detection, promote their regulatory effects via the 3'-untranslated binding region (3'-UTR) of target messenger RNA in posttranscriptional regulation of genes and also play a pivotal role in modulating resistance to chemotherapeutic agents. These small noncoding RNAs have also a critical role in CRC stem cells (CRCSCs) regulation, comprising self-renewal, differentiation, and tumorigenesis. Cancer stem cells (CSCs) are distinctive cell types inside a tumor tissue that are believed to derive from normal somatic stem cells. The CSCs have self-renewal abilities, angiogenesis, as well as specific surface markers expression characteristics. Furthermore, they are frequently criticized for tumor maintenance, treatment resistance, tumor development, and distant metastasis. In this review, we discuss the current understandings of CRCSCs and their environment with a focus on the role of miRNAs on the regulation of CSCs and their targeting application in CRC treatment.

Knockdown of MSI1 inhibits the proliferation of human oral squamous cell carcinoma by inactivating STAT3 signaling

Musashi RNA-binding protein 1 (MSI1) is highly expressed in several types of cancer; however, its role in oral squamous cell carcinoma (OSCC) remains unknown. The purpose of this study was to investigate the probable mechanism underlying the involvement of MSI1 in OSCC. The results demonstrated that MSI1 was upregulated in OSCC tissues, but not in adjacent healthy tissues. MSI1 silencing resulted in decreased cell proliferative, invasive and migrative capacity. In addition, MSI1 silencing led to cell cycle arrest at the S phase, downregulation of c-Myc and cyclin D1, and upregulation of p21 and p27 levels. Additional studies demonstrated that MSI1 suppression inhibited the activation of signal transducer and activator of transcription 3 (STAT3) signaling. Accordingly, the findings of the present study suggested that MSI1 silencing can suppress OSCC cell proliferation and progression, in part by inhibiting the activation of the c-Myc/STAT3 pathway.

Correlation of clinicopathological features and LGR5 expression in colon adenocarcinoma

Colon cancer stem cells (CSCs) are closely related to tumorigenesis and treatment response, and LGR5 is currently the most robust and reliable CSC marker in colorectal cancer (CRC). However, LGR5 expression in CRC tumor budding (TB) is not well understood. We examined the clinicopathological and prognostic significance of LGR5 in CRC TB. LGR5 expression was evaluated by RNAscope, a newly developed RNA in situ hybridization technique, using a tissue microarray consisting of 55 patient samples of TB in colon adenocarcinoma (CA) selected from the medical archives at our hospital. Patients were stratified into negative and positive LGR5 expression groups. Inflammatory cell infiltration was weaker and histological grade was lower in the LGR5-positive group compared with the LGR5-negative group (P = 0.0407 and P = 0.0436, respectively). There was a significant difference in OS between the LGR5-positive group and LGR5-negative group (log-rank test, P = 0.0088). Cox proportional hazards models revealed that the LGR5-positive group (Overall survival (OS) = 0.37, 95% CI: 0.17-0.79, P = 0.0101) had better OS. LGR5 expression may be affected by inflammatory cell infiltration in the budding area of CA and is an important potential marker of prognosis.

Prognostic impact of mRNA levels of LGR5 transcript variants in OSCC patients

Background

The human leucine-rich, repeat-containing G protein-coupled receptor 5 (LGR5) is a stem cell marker in numerous adult tissues and is overexpressed in a large number of human carcinoma including colon cancer, breast cancer and oral squamous cell carcinomas (OSCC). The role of the full length transcript (LGR5FL) in progression and prognosis of several cancers was reported. However, the biological function of three splice variants of LGR5 (LGR5Δ5, LGR5Δ8 and LGR5Δ5–8) has yet to be thoroughly investigated.

Methods

Seventy-eight frozen tumor samples from adult OSCC patients were studied using quantitative real-time TaqMan™ PCR analysis. The mRNA levels of full length LGR5, the splice variant of LGR5 lacking exon 5 (LGR5Δ5), the splice variant of LGR5 lacking exon 8 (LGR5Δ8) and the mRNA level of all known transcript variants together (LGR5all) were quantified and correlated to overall and disease-specific survival of OSCC patients, clinical parameters and the mRNA level of different tumor-associated markers.

Results

An elevated level of tumoral LGR5Δ5 mRNA, but not LGR5FL, LGR5Δ8 or LGR5all mRNA was significantly associated with a poor prognosis for the overall and disease-specific survival of OSCC patients (hazard ratio (HR) = 2.0; p = 0.02; 95% CI: 1.1–3.7; HR = 3.2; p = 0.01; 95% CI: 1.3–8.0; multivariable Cox regression), respectively. Additionally, a higher tumoral level of LGR5Δ5 mRNA in primary tumors was associated with the occurrence of regional lymph node metastases in OSCC patients (odds ratio (OR) = 3.1; p = 0.022; 95% CI: 1.2–7.9; binary logistic regression). Furthermore, the mRNA levels of all investigated LGR5 transcript variants were significantly correlated with the mRNA expression of Wnt-target genes and markers of epithelial-to-mesenchymal transition (EMT).

Conclusion

The mRNA level of the LGR5 splice variant LGR5Δ5 is an independent negative prognostic marker for overall and disease-specific survival and metastasis in OSCC patients. Additionally, we suggest, all LGR5 transcript variants are involved in the EMT process mainly through activating the Wnt-signalling pathway.

Increased expression of Ki-67 is a poor prognostic marker for colorectal cancer patients: a meta analysis

Background

The prognostic value of Ki-67 expression in colorectal cancer patients was controversial. Therefore, this meta analysis was conducted to ascertain the prognostic value of Ki-67 expression in colorectal cancer patients.

Methods

The electronic databases, including EMBASE, PubMed, Cochrane Library and Web of Knowledge database, were searched from January 1970 to July 2017. The pooled hazard ratios and 95% confidence intervals were calculated to evaluate the prognostic value of Ki-67 expression for colorectal cancer patients.

Results

Totally 34 eligible studies and 6180 colorectal cancer patients were included in the present meta analysis. The pooled hazard ratios were 1.54(95% CI 1.17–2.02, P = 0.005) for overall survival and 1.43(1.12–1.83, P = 0.008) for disease free survival in univariate analysis. After adjustment of other prognostic factors, the pooled HR was 1.50(95% CI 1.02–2.22, P = 0.03) for overall survival in multivariate analysis.

Conclusion

The present meta analysis demonstrated that high Ki-67 expression is significantly correlated with poor overall survival and disease free survival, indicating that high Ki-67 expression may serve as a valuable predictive method for poor prognosis of colorectal cancer patients.

Expression Patterns for TETs, LGR5 and BMI1 in Cancer Stem-like Cells Isolated from Human Colon Cancer

BACKGROUND

Colon tumor is generated and maintained by a small subset of chemo-resistant cancer cells known as Cancer Stem-like Cells (CSCs) that are able to self-renew and differentiate into various cell types within the cancer milieu. CSCs are identified through expression of CD133 that is the most important surface marker of these cells. Epithelial Cell Adhesion Molecule (EpCAM) is another colon CSCs marker. Other markers that are probably involved in colon tumorigenesis are Leucine-rich repeat-containing G-protein-coupled Receptor 5 (LGR5), B cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) and Ten-Eleven Translocations (TETs).

METHODS

Here, mRNA expression rates of LGR5, BMI1 and TETs were surveyed by real-time PCR. After collection and digestion, colon samples were used to isolate CD133 and EpCAM positive CSCs through evaluation of AC133 EpCAM by Magnetic Activated Cell Sorting (MACS) and flow cytometry. Real-time PCR was carried out for assessing expressions of LGR5, BMI1 and TETs.

RESULTS

High expressions for LGR5, BMI1, TET1 and TET2 in the CD133 and EpCAM positive CSCs (p≤0.05 vs. non-CSCs) were found. TET3, however, showed no significant changes for mRNA expression in the CSCs.

CONCLUSION

In conclusion, high mRNA expressions for LGR5, BMI1, TET1 and TET2 in the CD133 and EpCAM positive CSCs may be a useful criterion for better identification of the cells involved in colon cancer in order to specify therapeutic targets against this type of cancer.

Leucine-rich repeat-containing G-protein-coupled receptor 5 expression and clinicopathological features of colorectal neuroendocrine neoplasms

LGR5 is expressed in various tumors and has been identified as a putative intestinal stem cell marker. Here we investigated LGR5 expression in colorectal neuroendocrine neoplasms and analyzed the correlation with pathological characteristics. We evaluated the clinicopathological features of 8 neuroendocrine tumor (NET) grade 1 (NET G1), 4 NET Grade 2 (NET G2), and 8 NET Grade 3 (NET G3; also termed neuroendocrine carcinoma, or NEC) cases. We examined LGR5 expression using an RNAscope, a newly developed RNA in situ hybridization technique, with a tissue microarray of the neuroendocrine neoplasm samples. LGR5 staining in individual tumor cells was semi-quantitatively scored using an H-score scale. We also performed a combination of LGR5 RNA in situ hybridization and synaptophysin immunohistochemistry. All cases contained tumor cells with some LGR5-positive dots. For all cases, H-scores showed a positive correlation with nuclear beta-catenin expression. In the NEC group, there was a strong positive correlation between H-score and beta-catenin expression. Our findings suggest that LGR5 may serve as a stem cell marker in NEC, as is the case in colon adenocarcinoma. The positive correlation between H-score and beta-catenin expression suggests that LGR5 expression might be affected by beta-catenin expression in neuroendocrine neoplasms and especially in NEC.

Expression Profile of LGR5 and Its Prognostic Significance in Colorectal Cancer Progression

We investigated the expression profile of leucine-rich, repeat-containing, G-protein-coupled receptor 5 (LGR5) during colorectal cancer (CRC) progression and determined the prognostic impact of LGR5 in a large cohort of CRC samples. LGR5 expression was higher in CRCs than in normal mucosa, and was not associated with other cancer stem cell markers. LGR5 positivity was observed in 68% of 788 CRCs and was positively correlated with older age, moderately to well-differentiated cells, and nuclear β-catenin expression. Enhanced LGR5 expression remained persistent during the adenoma-carcinoma transition, but markedly declined in the budding cancer cells at the invasive fronts, which was not due to altered wingless-type mouse mammary tumor virus integration site family (Wnt) or epithelial-mesenchymal transition signaling. LGR5 showed negative correlations with microsatellite instability and CpG island methylator phenotype, and was not associated with KRAS or BRAF mutation. Notably, LGR5 positivity was an independent prognostic marker for better clinical outcomes in CRC patients. LGR5 overexpression attenuated tumor growth by decreasing ERK phosphorylation along with decreased colony formation and migration abilities in DLD1 cells. Likewise, knockdown of LGR5 expression resulted in a decline in the colony-forming and migration capacities in LoVo cells. Taken together, our data suggest a suppressive role of LGR5 in CRC progression.

DEAD box protein DDX1 promotes colorectal tumorigenesis through transcriptional activation of the LGR5 gene

DDX1, a member of the DEAD box RNA helicase family, plays a critical role in testicular tumors. However, it remains to be clarified whether DDX1 is involved in other types of malignant tumors such as colorectal cancer. We disrupted the DDX1 gene in a human colorectal cancer cell line LoVo using the CRISPR/Cas9‐mediated gene‐targeting system. DDX1‐KO LoVo cells exhibited a much slower growth rate, produced fewer colonies in soft agar medium, and generated smaller solid tumors in nude mice than parental LoVo cells. Such phenotypes of the DDX1‐KO cells were mostly reversed by exogenous expression of DDX1. These results indicate that DDX1 is required for tumorigenicity of colorectal cancer cells. In the DDX1‐KO cells, the cancer stem cell marker genes LGR5, CD133, ALDH1 and SOX2 were markedly suppressed. Among them, expression of LGR5, which is essential for tumorigenicity of colorectal cancer cells, was restored in the DDX1‐transfected DDX1‐KO cells. Consistently, the DDX1‐KO cells lost sphere‐forming capacity in a DDX1‐dependent fashion. Reporter and chromatin immunoprecipitation assays revealed that DDX1 directly bound to the −1837 to −1662 region of the enhancer/promoter region of the human LGR5 gene and enhanced its transcription in LoVo cells. Repression of LGR5 by DDX1 knockdown was observed in 2 other human colorectal cancer cell lines, Colo320 and SW837. These results suggest that LGR5 is a critical effector of DDX1 in colorectal cancer cells. The DDX1‐LGR5 axis could be a new drug target for this type of malignant cancer.

Heterogeneous expression of Lgr5 as a risk factor for focal invasion and distant metastasis of colorectal carcinoma

Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is a downstream target gene of the Wnt/β-catenin signaling pathway and identified as a marker of cancer stem-like cells of colorectal carcinoma (CRC). Here, the heterogeneous expression pattern of Lgr5 and its clinical significance were studied by the method of immunohistochemistry in 204 CRC tumors at various pTNM stages. Lgr5 expression was found in 82.4% (168/204) cases, significantly more common in neoplastic cells at the infiltrative front (n = 59.5%, 110/185) or at the expanding front (n = 36.4%, 59/162) than at the tumor center (n = 16.7%, 34/204; P < 0.01). Tumor budding (TB) was discovered with significantly higher Lgr5 expression (n = 39.3%, 57/145, P = 0.03) and significantly positively correlated between Lgr5 expression and TB grade (r = 0.19, P = 0.02). Additionally, both positive Lgr5 expression and a high TB grade were significantly correlated to the depth of tumor invasion, lymph node metastasis, pTNM stage, and perineural invasion (P < 0.01). The study results suggest that heterogeneous expression of Lgr5 may be a risk factor for local invasion and distant metastasis of CRC.

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.

RNAi-mediated inhibition of Lgr5 leads to decreased angiogenesis in gastric cancer

Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) is a novel gastric cancer marker. However, it is unclear whether it can play roles in tumor angiogenesis. In this study, we aim to investigate the role of Lgr5 on gastric cancer angiogenesis. Lgr5, VEGF expression levels and microvessel density (MVD) were detected in tumor tissue. Then, Lgr5 mRNA was downregulated by small interference RNA technique. Western blotting and real-time quantitative PCR (qRT-PCR) were performed to detect the expression of Lgr5 and VEGF protein and mRNA in Lgr5 siRNA-transfected gastric cancer cells. The effect of silencing Lgr5 on angiogenesis was examined by assessing human umbilical vein endothelia cell (HUVEC) capillary tube formation. The results indicated that Lgr5 expression was upregulated in gastric cancer and positively correlated with VEGF (r=0.305, P=0.001) and MVD (r=0.312, P=0.001). Silencing of Lgr5 expression resulted in suppression of VEGF mRNA and protein (all P=0.001). Moreover, when HUVECs were stimulated with conditioned medium from Lgr5 siRNA-transfected gastric cancer cells, tube formation was significantly decreased (2.51 ± 0.19 mm/mm2) compared with the treatment with regular cell culture medium (DMEM) (7.34 ± 0.30 mm/mm2) or medium from control siRNA-transfected cells (7.18 ± 0.33 mm/mm2) (all P=0.001). In conclusion, Lgr5 plays important roles in angiogenesis. Lgr5-specific siRNA could be designed into an effective therapeutic agent to inhibit gastric cancer angiogenesis.

TROY is a promising prognostic biomarker in patients with colorectal cancer

Tumor necrosis factor receptor superfamily member 19 (TROY) is involved in the Wnt/β-catenin signaling pathway and interacts with leucine-rich repeat containing G-protein-coupled receptor 5 (LGR5), which is a well-known biomarker of cancer stem cells and a prognostic marker of colorectal cancer (CRC). Because there have been no studies to evaluate the prognostic significance of TROY, we performed the present study to determine whether TROY can be a prognostic biomarker in CRC patients. We evaluated TROY expression levels in 100 CRC tissues by quantitative real-time PCR and investigated the association of TROY expression levels with clinicopathologic features. Cancer stage and TROY expression level were found to be independent prognostic factors of disease-free survival. Moreover, TROY overexpression was the sole independent prognostic factor of disease-free survival in patients with stage II and III CRC. These results suggest that analysis of TROY might help predict clinical outcome in patients with CRC. To support our findings, confirmatory studies using independent data sets are needed.

Leucine-rich repeat-containing G protein-coupled receptor 5 and CD133 expression is associated with tumor progression and resistance to preoperative chemoradiotherapy in low rectal cancer

Preoperative chemoradiotherapy has been performed as a standard therapy for advanced low rectal cancer. Cancer stem cells (CSCs) have been reported to contribute to resistance to treatment and patient prognosis. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) and cluster of differentiation (CD133) are putative markers for CSCs. However, their prognostic ability remains unknown, and evaluation of a single marker can be insufficient due to the heterogeneity of cancer. LGR5 and CD133 expression was immunohistochemically evaluated in surgical specimens of 56 patients who received curative resection following chemoradiotherapy for advanced low rectal cancer. In addition, the correlations between their expression levels, and clinicopathological features and patient prognosis were asessed. LGR5 expression was significantly correlated with lymphatic invasion, lymph node metastasis, and tumor node metastasic (TNM) stage. CD133 expression was significantly correlated with vascular invasion and the tumor regression grade. Combined expression was significantly correlated with lymphatic invasion, tumor regression grade and TNM stage, but not with overall, and disease-free survival. LGR5 and CD133 expressions may represent useful markers associated with tumor progression and resistance to chemoradiotherapy in patients with low rectal cancer. Furthermore, combined expression of these markers may be a more useful marker compared with the expression of each single marker.

Knockdown of MSI1 inhibited the cell proliferation of human osteosarcoma cells by targeting p21 and p27

Osteosarcoma is the most common type of primary bone cancer in children and adolescents, but its mechanism remains unclear. Musashi RNA-binding protein 1 (MSI1) is highly expressed in certain cancer types and functions as a putative progenitor/stem cell marker. In the present study, it was demonstrated that MSI1 expression in osteosarcoma tissue was higher compared with in the paraneoplastic tissue samples. Knockdown of MSI1 using shRNA in MG-63 and HOS cells inhibited cell proliferation in vitro and tumor formation in vivo, suggesting that MSI1 serves an essential role in osteosarcomagenesis. Further investigations demonstrated that the knockdown of MSI1 leads to the cell cycle arrest at G₀/G₁ phase, and the upregulation of p21 and p27 protein expression in osteosarcoma cells. Additionally, luciferase assays demonstrated that MSI1 can bind to the 3′ untranslated regions of p21 and p27 mRNA. In conclusion, the results of the present study suggest that the knockdown of MSI11 can suppress cell proliferation of osteosarcoma by targeting p21 and p27 and subsequently inhibiting cell cycle progression.

Elevated expression of Tie1 is accompanied by acquisition of cancer stemness properties in colorectal cancer

The Tie receptors 1 and 2 (Tie1/2) play crucial roles in embryonic angiogenesis. Recent studies suggest enhanced expression of Tie1 in several types of cancer and negative correlations between Tie1 levels and clinical outcome. These observations suggest important functions of Tie1 not only for vascular formation but also in tumorigenesis. Ligands for Tie2, that is angiopoietins 1-4, have been identified, but not for Tie1. To determine the molecular functions of Tie1, its detailed characterization in tumors would be helpful. Herein, we report that Tie1 is up-regulated in colorectal cancer. Detailed analysis using tumor-bearing models and immunohistochemistry combined with Flow cytometric analysis and cell sorting (FACS) revealed that Tie1 protein was expressed in a small population of malignant tumor cells. Intriguingly, Tie1 expression was observed and could be maintained only in vivo. Further analysis using sphere-formation culture revealed that Tie1-positive cells are enriched within the population of tumor cells with cancer stemness properties. Indeed, Tie1-positive tumor cells derived from a murine model overexpressed Lgr5, a typical stemness marker for colorectal cancer. Our results provide a novel insight into Tie1 function in tumorigenesis and suggest clinical applications to target cancer stem cells.

Lgr5 is a marker for fetal mammary stem cells, but is not essential for stem cell activity or tumorigenesis

The search for the bipotent mammary stem cells that drive mammary development requires markers to enable their prospective isolation. There is general agreement that bipotent mouse mammary stem cells are abundant in late fetal development, but their existence in the adult is vigorously debated. Among markers useful for mammary stem cell identification, the Wnt co-receptor Lgr5 has been suggested by some to be both "necessary and sufficient" for bipotency and transplantation of adult mammary stem cell activity, though other studies disagree. Importantly, the relevance of Lgr5 to the bipotency of fetal mammary stem cells has not been studied. We show here that expression of a fluorescent protein driven by the endogenous Lgr5 promoter enables significant fetal mammary stem cell enrichment. We used lineage tracing to demonstrate embryonic cells expressing Lgr5 are bipotent, while their adult counterparts are myoepithelial restricted. Importantly, our data conclusively demonstrate that Lgr5 is dispensable for both fetal and adult mammary stem cell activity and for the development of mammary tumors.

LGR5 and CD133 as prognostic and predictive markers for fluoropyrimidine-based adjuvant chemotherapy in colorectal cancer

BACKGROUND

Expression of leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) gene is associated with a metastatic phenotype and poor prognosis in colorectal cancer (CRC). CD133 expression is a putative cancer stem cell marker and a proposed prognostic marker in CRC, whereas the predictive value of CD133 expression for effect of adjuvant chemotherapy in CRC is unclear.

MATERIAL AND METHODS

For the study of LGR5 mRNA and CD133 expression, tissue microarrays from 409 primary CRC stage II and III tumors, where patients had been randomized to adjuvant chemotherapy or surgery only, were available. LGR5 mRNA and CD133 expression were assessed by in situ hybridization (ISH) and immunohistochemistry (IHC), respectively. LGR5 mRNA and CD133 expression as prognostic and predictive markers were evaluated by univariate and multivariate analyses.

RESULTS

For all CRC patients, positive LGR5 mRNA and CD133 expression were associated with classic adenocarcinoma histology type (p = 0.001 and p = 0.014, respectively). Positive LGR5 mRNA expression was also associated with smaller tumor diameter for CRC stage II (p = 0.005), but not for CRC stage III (p = 0.054). For CRC stage II, lack of LGR5 mRNA expression was associated with longer time to recurrence (TTR) in Kaplan-Meier (p = 0.045) and in multivariate Cox analysis (HR 0.27, 95% CI 0.08-0.95, p = 0.041). For colon cancer stage III patients, lack of CD133 expression was associated with better effect of adjuvant chemotherapy (p = 0.016) in Kaplan-Meier univariate analysis, but the interaction between CD133 and adjuvant chemotherapy was not statistically significant in multivariate analysis (HR 0.59, 95% CI 0.18-1.89, p = 0.374).

CONCLUSION

LGR5 mRNA expression is a prognostic factor for CRC stage II patients, whereas the value of CD133 expression as prognostic and predictive biomarker is inconclusive.