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

Peristalsis-Associated Mechanotransduction Drives Malignant Progression of Colorectal Cancer

Introduction

In the colorectal cancer (CRC) tumor microenvironment, cancerous and precancerous cells continuously experience mechanical forces associated with peristalsis. Given that mechanical forces like shear stress and strain can positively impact cancer progression, we explored the hypothesis that peristalsis may also contribute to malignant progression in CRC. We defined malignant progression as enrichment of cancer stem cells and the acquisition of invasive behaviors, both vital to CRC progression.

Methods

We leveraged our peristalsis bioreactor to expose CRC cell lines (HCT116), patient-derived xenograft (PDX1,2) lines, or non-cancerous intestinal cells (HIEC-6) to forces associated with peristalsis in vitro. Cells were maintained in static control conditions or exposed to peristalsis for 24 h prior to assessment of cancer stem cell (CSC) emergence or the acquisition of invasive phenotypes.

Results

Exposure of HCT116 cells to peristalsis significantly increased the emergence of LGR5+ CSCs by 1.8-fold compared to static controls. Peristalsis enriched LGR5 positivity in several CRC cell lines, notably significant in KRAS mutant lines. In contrast, peristalsis failed to increase LGR5+ in non-cancerous intestinal cells, HIEC-6. LGR5+ emergence downstream of peristalsis was dependent on ROCK and Wnt activity, and not YAP1 activation. Additionally, HCT116 cells adopted invasive morphologies when exposed to peristalsis, with increased filopodia density and epithelial to mesenchymal gene expression, in a Wnt dependent manner.

Conclusions

Peristalsis associated forces drive malignant progression of CRC via ROCK, YAP1, and Wnt-related mechanotransduction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00776-w.

The role of microvesicles as biomarkers in the screening of colorectal neoplasm

Background

Colorectal cancer (CRC) is the second cause of cancer death worldwide. The role of circulating microvesicles as a screening tool is a novel, yet effective approach that warrants prioritised research.

Methods

In a two‐gate diagnostic accuracy study, 35 patients with benign colorectal polyps (BCRP) (n = 16) and colorectal cancer (CRC) (n = 19) were compared to 17 age‐matched healthy controls. Total annexin‐V positive microvesicles and sub‐populations positive for selected biomarkers relevant to bowel neoplasm were evaluated in patients' plasma using flow cytometry. Statistical methods including factor analysis utilising two component factors were performed to obtain optimal diagnostic accuracy of microvesicles in identifying patients with colorectal neoplasms.

Results

Total plasma microvesicles, and sub‐populations positive for CD31, CD42a, CD31+/CD42a‐, EPHB2, ICAM and LGR5 (component factor‐1) were able to identify patients with BCRP and CRC with a receiver operator curve (AUC) accuracy of a 100% (95% CI: 100%–100%) and 95% (95% CI: 88%–100%), respectively. To identify patients with BCRP, a cut‐off point value of component factor‐1761 microvesicles/μl demonstrated a 100% sensitivity, specificity and negative predictive value (NPV) and a 93% positive predictive value (PPV). To identify patients with CRC, a cut‐off value of component factor‐1 ³439 microvesicles/μl demonstrated a 100% sensitivity, specificity and NPV and a 65% PPV. CEA+ microvesicles sub‐population were significantly (p < 0.02) higher in CRC in comparison to BCRP.

Conclusions

Microvesicles as biomarkers for the early and accurate detection of CRC is a simple and effective tool that yields a potential breakthrough in clinical management.

Disruption of the crypt niche promotes outgrowth of mutated colorectal tumor stem cells

Recent data establish a logarithmic expansion of leucine rich repeat containing G protein coupled receptor 5–positive (Lgr5⁺) colonic epithelial stem cells (CESCs) in human colorectal cancer (CRC). Complementary studies using the murine 2-stage azoxymethane–dextran sulfate sodium (AOM-DSS) colitis-associated tumor model indicate early acquisition of Wnt pathway mutations drives CESC expansion during adenoma progression. Here, subdivision of the AOM-DSS model into in vivo and in vitro stages revealed DSS induced physical separation of CESCs from stem cell niche cells and basal lamina, a source of Wnt signals, within hours, disabling the stem cell program. While AOM delivery in vivo under non-adenoma-forming conditions yielded phenotypically normal mucosa and organoids derived thereof, niche injury ex vivo by progressive DSS dose escalation facilitated outgrowth of Wnt-independent dysplastic organoids. These organoids contained 10-fold increased Lgr5⁺ CESCs with gain-of-function Wnt mutations orthologous to human CRC driver mutations. We posit CRC originates by niche injury–induced outgrowth of normally suppressed mutated stem cells, consistent with models of adaptive oncogenesis.

The involvement of epithelial-to-mesenchymal transition in doxorubicin resistance: Possible molecular targets

Considering the fact that cancer cells can switch among various molecular pathways and mechanisms to ensure their progression, chemotherapy is no longer effective enough in cancer therapy. As an anti-tumor agent, doxorubicin (DOX) is derived from Streptomyces peucetius and can induce cytotoxicity by binding to topoisomerase enzymes to suppress DNA replication, leading to apoptosis and cell cycle arrest. However, efficacy of DOX in suppressing cancer progression is restricted by development of drug resistance. Cancer cells elevate their metastasis in triggering DOX resistance. The epithelial-to-mesenchymal transition (EMT) mechanism participates in transforming epithelial cells into mesenchymal cells that have fibroblast-like features. The EMT diminishes intercellular adhesion and enhances migration of cells that are necessary for carcinogenesis. Various oncogenic molecular pathways stimulate EMT in cancer. EMT can induce DOX resistance, and in this way, upstream mediators such as ZEB proteins, microRNAs, Twist1 and TGF-β play a significant role. Identification of molecular pathways involved in EMT regulation and DOX resistance has resulted in using gene therapy such as microRNA transfection and siRNA in overcoming chemoresistance. Furthermore, curcumin and formononetin, owing to their cytotoxicity against cancer cells, can suppress EMT in mediating DOX sensitivity. For promoting efficacy in DOX sensitivity, nanoparticles have been developed for boosting ability in EMT inhibition.

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.

Most colitis associated carcinomas lack expression of LGR5: a preliminary study with implications for unique pathways of carcinogenesis compared to sporadic colorectal carcinoma

Background

Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a component of the Wnt receptor complex, is thought to lineage label gastric and intestinal stem cells. LGR5 expression is increased in colorectal carcinoma (CRC) compared to normal tissue. Colitis associated colorectal adenocarcinoma (CAC) often shows distinct morphologic and molecular phenotypes compared to sporadic cases. However, the expression profile of LGR5, and by extension the potential role of an intestinal stem cell phenotype, has not been well described in a series of human CAC.

Method

RNA in situ hybridization (ISH) for LGR5 expression on 30 CACs (12 cases with conventional morphology and 18 cases with non-conventional type morphology) from 29 inflammatory bowel disease (IBD) patients was performed and compared the expression profile to a control group of 10 sporadic CRCs. Immunohistochemistry for beta-catenin and SATB2 was performed on the 30 CACs.

Result

LGR5 was positive in 30% (9/30) of CAC cases and 90% (9/10) of sporadic CRCs (p = 0.002). A large majority (89%) of LGR5 positive CACs were of the conventional histologic type, and conventional type CAC showed a significantly higher LGR5 score (median 3.0; interquartile range 1.75–3.25) than non-conventional type CAC (median 1.5; interquartile range 1.00–2.00) (p = 0.034). CAC with conventional morphology did have a lower level of LGR5 expression than sporadic CRC. Sporadic CRCs showed a significantly higher LGR5 level score than non-conventional type CACs (p < 0.001). Nuclear translocation of beta-catenin was strongly associated with LGR5 expression (p = 0.003), however no significant association was identified between SATB2 expression and LGR5 expression status in CACs.

Conclusion

These findings suggest that the wider spectrum of tumor morphology in CAC may be associated with absence of a LGR5-expressing intestinal stem cell phenotype.

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.

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.

m6A methyltransferase METTL3 maintains colon cancer tumorigenicity by suppressing SOCS2 to promote cell proliferation

N⁶-methyladenosine (m⁶A) RNA modification maintained by N6-methyltransferases and demethylases is involved in multiple biological functions. Methyltransferase like 3 (METTL3) is a major N⁶-methyltransferase. However, the role of METTL3 and its installed m⁶A modification in colorectal tumorigenesis remains to be fully elucidated. METTL3 is highly expressed as indicated in colorectal cancer samples in the TCGA and Oncomine databases, implying its potential role in colon tumorigenesis. SW480 cell line with stable METTL3 knockout (METTL3-KO) was generated using CRISPR/Cas9 and were confirmed by the loss of METTL3 expression and suppression of m⁶A modification. The proliferation of METTL3-KO cells was significantly inhibited compared with that of control cells. METTL3-KO decreased the decay rate of suppressor of cytokine signaling 2 (SOCS2) RNA, resulting in elevated SOCS2 protein expression. m⁶A-RNA immunoprecipitation-qPCR (MeRIP-qPCR) revealed that SOCS2 mRNA was targeted by METTL3 for m⁶A modification. Similar to METTL3-KO SW480 cells, SW480 cells treated with 3-deazaadenosine, an RNA methylation inhibitor, exhibited elevated SOCS2 protein expression. Increased levels of SOCS2 in METTL3-KO SW480 cells were associated with decreased expression of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), contributing to the inhibition of cell proliferation. The underlying associations among METTL3, SOCS2, and LGR5 were further confirmed in SW480 cells transfected with si-METTL3 and in tumor samples from patients with colorectal cancer. Taken together, our data demonstrate that an increased level of METTL3 may maintain the tumorigenicity of colon cancer cells by suppressing SOCS2.

Targeting Cancer Stem Cells by Genetically Engineered Chimeric Antigen Receptor T Cells

The term cancer stem cell (CSC) starts 25 years ago with the evidence that CSC is a subpopulation of tumor cells that have renewal ability and can differentiate into several distinct linages. Therefore, CSCs play crucial role in the initiation and the maintenance of cancer. Moreover, it has been proposed throughout several studies that CSCs are behind the failure of the conventional chemo-/radiotherapy as well as cancer recurrence due to their ability to resist the therapy and their ability to re-regenerate. Thus, the need for targeted therapy to eliminate CSCs is crucial; for that reason, chimeric antigen receptor (CAR) T cells has currently been in use with high rate of success in leukemia and, to some degree, in patients with solid tumors. This review outlines the most common CSC populations and their common markers, in particular CD133, CD90, EpCAM, CD44, ALDH, and EGFRVIII, the interaction between CSCs and the immune system, CAR T cell genetic engineering and signaling, CAR T cells in targeting CSCs, and the barriers in using CAR T cells as immunotherapy to treat solid cancers.

Correlation of Clinicopathological Features and LGR5 Expression in Triple-Negative Breast Cancer

LGR5 is the most robust known stem cell marker for gastrointestinal tumors, but there are few reports in breast cancer. Triple negative breast cancer (TNBC) is the most malignant subtype of breast cancer, and thus identification of new cancer stem cell populations in TNBC may help to identify targeted therapies. LGR5 expression was evaluated by RNAscope, a newly developed RNA in situ hybridization technique, using a tissue microarray consisting of 43 patient samples of TNBC selected from the medical archives at our hospital. Patients were stratified into negative and positive LGR5 expression groups. Tumor necrosis was greater in the LGR5-positive group compared with the LGR5-negative group (P = .026). Mitosis tended to show a high value in the LGR5-positive group compared with the LGR5-negative group (P = .0831), while stage tended to show a high stage in the LGR5-positive group compared with the LGR5-negative group (P = .0617). Cox proportional hazards models revealed that the LGR5-positive group (overall survival (OS) = 2.12; 95% CI: 2.12-2.12; P = 0.1575) had no relationship with OS. LGR5 expression is associated with tumor necrosis of TNBC and suggested higher malignant potential.

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.

Lgr5-mediated p53 Repression through PDCD5 leads to doxorubicin resistance in Hepatocellular Carcinoma

The devastating prognosis of hepatocellular carcinoma (HCC) is partially attributed to chemotherapy resistance. Accumulating evidence suggests that the epithelial-mesenchymal transition (EMT) is a key driving force of carcinoma metastasis and chemoresistance in solid tumors. Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5), as an EMT inducer, is involved in the potentiation of Wnt signaling in HCC. This study proposes uncovering the roles of Lgr5 in Doxorubicin (Dox) resistance of HCC to improve treatment efficacy for HCC.

Methods: We investigated the expression and significance of Lgr5 in HCC tissue and different cell lines. The effect of Lgr5 in EMT and Dox resistance was analyzed in HCC cells and implanted HCC tumor models. A two-hybrid analysis, using the Lgr5 gene as the bait and a HCC cDNA library, was used to screen targeted proteins that interact with Lgr5. The positive clones were identified by coimmunoprecipitation (Co-IP) and Glutathione-S-transferase (GST) pull-down. The impact of the interaction on Dox resistance was investigated by a series of assays in vitro and in vivo .

Result: We found that Lgr5 was upregulated and positively correlated with poor prognosis in HCC. Additionally, it functioned as a tumor promoter to increase cell migration and induce EMT in HCC cells and increase the resistance to Dox. We identified programmed cell death protein 5 (PDCD5) as a target gene of Lgr5 and we found that PDCD5 was responsible for Lgr5-mediated Dox resistance. Further analysis with Co-IP and GST pull-down assays showed that the N-terminal extracellular domain of Lgr5 could directly bind to PDCD5. Lgr5 induced p53 degradation by blocking the nuclear translocation of PDCD5 and leading to the loss of p53 stabilization. Lgr5 showed a protection against the inhibition of Dox on the growth of tumor subcutaneously injected. Moreover, Lgr5 suppressed Dox-induced apoptosis via the p53 pathway and attenuated the cytotoxicity of Dox to HCC.

Conclusion: Lgr5 induces the EMT and inhibits apoptosis, thus promoting chemoresistance by regulating the PDCD5/p53 signaling axis. Furthermore, Lgr5 may be a potential target gene for overcoming Dox resistance.

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.

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.

Overexpression of leucine-rich repeat-containing G protein-coupled receptor 5 predicts poor prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and the fifth leading cause of cancer-related death worldwide. Novel prognostic biomarkers are urgently needed for patients with HCC. Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) overexpression may promote tumor metastasis in HCC. However, few studies investigate the prognosis predictive role of LGR5 in patients with HCC. Herein, we aimed to examine the expression level of LGR5 in tumors and its correlation with clinical characteristics and survivals of patients with HCC. LGR5 expression in tumor specimens and adjacent tissue resected from 66 patients were detected by immunohistochemistry. The results showed that the expression of LGR5 was markedly higher in HCC than in normal adjacent tissues (P = .006). High expression of LGR5 was significantly correlated with later disease stage (P = .009). In addition, high LGR5 expression was remarkably correlated with short overall survival than those with low LGR5 expression (P < .05). The median overall survival of patients with high LGR5 expression was 12 months, whereas that of patients with low LGR5 expression was still not reached (longer than 70 months). Notably, in our limited cases, we did not detect any difference in tumor size, lymphatic invasion, or metastasis in patients with high or low expression of LGR5. In conclusion, high protein level of LGR5 was associated with poor prognosis of these patients. LGR5 appears to be a valuable prognostic predictor clinically and a potential target in HCC therapy.

Verrucarin J inhibits ovarian cancer and targets cancer stem cells

Ovarian Cancer is the fifth leading cause of death among women from cancer. Cancer stem cells are a small population of cells present in cancer and the cause of chemoresistance and recurrence of cancer. We tested a new compound "Verrucarin J (VJ)", a metabolite of the Myrothecium fungus family, and showed that VJ significantly inhibits cell proliferation of both cisplatin-sensitive (A2780 and OVCAR5) and cisplatin-resistant (A2780/CP70) cell lines in a dose- and time-dependent manner with IC₅₀ value of approximately 10 nM after 48 h of treatment. VJ was found to induce apoptosis, DNA damage, and generation of reactive oxygen species (ROS). Treatment of A2780 cells with VJ resulted in a significant suppression of expression of CSCs markers including ALDH1, LGR5, NANOG and OCT4 in a dose-dependent manner, elimination of ALDH1⁺ CSC population and inhibition of expression of Notch1 and Wnt1 signaling pathways. Our study also showed that VJ inhibited the tumorigenic potential (spheroid formation on ultralow attachment plates) of isolated ALDH1⁺ CSCs in vitro and tumor growth and metastasis in vivo. VJ resulted downregulation of expression of securin an "oncogene" involved in tumor growth and progression, indicating that securin may serve as a downstream signaling gene to mediate antitumor effects of VJ.

Logarithmic expansion of LGR5+ cells in human colorectal cancer

Stem cells of the small and large intestine are marked by expression of the Wnt target gene LGR5, a leucine-rich-repeat-containing G protein-coupled receptor. Previous studies reported increased expression of LGR5 in human colorectal cancer (CRC) compared to normal tissue either by immunohistochemistry or in situ hybridization (ISH). However, as these studies were semi-quantitative they did not provide a numerical estimate of the magnitude of this effect. While we confirm that LGR5⁺ cells are exclusively located at the base of normal human small and large intestinal crypts, representing approximately 6% of total crypt cells, we show this cell population is 10-fold expanded in all grades of CRC, representing as much as 70% of the cells of tumor crypt-like structures. This expansion of the LGR5 compartment coincides with maintenance of crypt-like glandular structure (adenomas, and well and moderately differentiated adenocarcinomas), and is reduced in poorly differentiated CRC, where crypt-like glandular architecture is lost, accompanied by reduced epithelial terminal differentiation. Altogether these results indicate that LGR5⁺ cell expansion is a hallmark of CRC tumorigenesis occurring during progression to adenoma, supporting CRC as a stem cell disease with implications for CRC therapy.

Inhibiting clathrin-mediated endocytosis of the leucine-rich G protein-coupled receptor-5 diminishes cell fitness

The leucine-rich G protein-coupled receptor-5 (LGR5) is expressed in adult tissue stem cells of many epithelia, and its overexpression is negatively correlated with cancer prognosis. LGR5 potentiates WNT/β-catenin signaling through its unique constitutive internalization property that clears negative regulators of the WNT-receptor complex from the membrane. However, both the mechanism and physiological relevance of LGR5 internalization are unclear. Therefore, a natural product library was screened to discover LGR5 internalization inhibitors and gain mechanistic insight into LGR5 internalization. The plant lignan justicidin B blocked the constitutive internalization of LGR5. Justicidin B is structurally similar to more potent vacuolar-type H⁺-ATPase inhibitors, which all inhibited LGR5 internalization by blocking clathrin-mediated endocytosis. We then tested the physiological relevance of LGR5 internalization blockade in vivo A LGR5-rainbow (LBOW) mouse line was engineered to express three different LGR5 isoforms along with unique fluorescent protein lineage reporters in the same mouse. In this manner, the effects of each isoform on cell fate can be simultaneously assessed through simple fluorescent imaging for each lineage reporter. LBOW mice express three different forms of LGR5, a wild-type form that constitutively internalizes and two mutant forms whose internalization properties have been compromised by genetic perturbations within the carboxyl-terminal tail. LBOW was activated in the intestinal epithelium, and a year-long lineage-tracing course revealed that genetic blockade of LGR5 internalization diminished cell fitness. Together these data provide proof-of-concept genetic evidence that blocking the clathrin-mediated endocytosis of LGR5 could be used to pharmacologically control cell behavior.

T-cell leukemia/lymphoma-1A predicts the clinical outcome for patients with stage II/III colorectal cancer

T-cell leukemia/lymphoma-1A (TCL1A) as a stem cell marker is abundantly expressed in embryonic stem cells and has been identified as an oncogene in various hematological malignancies such as chronic lymphocytic leukemia and B-cell lymphoma. However, with regard to its role in solid tumors, few studies are available and less are for colorectal cancer (CRC). In this study, we aim to investigate the expression and clinical significance of TCL1A in a cohort of 278 stage II/III CRC patients. As a result, we find TCL1A expression is higher in CRC tissues than that in adjacent normal tissues, and significantly correlated with tumor differentiation, TNM stage and Ki-67 positive rate. The prognostic analysis suggests that TCL1A expression is an independent factor affecting CRC-specific and disease-free survival of these patients. Furthermore, we find stage II/III patients with high TCL1A expression have a significantly higher rate of postoperative local recurrence and metastasis than those with low TCL1A expression. Finally, through subgroup analysis, we find TCL1A expression can stratify the outcome of stage II/III patients who received standard adjuvant chemotherapy. Taken together, our findings suggest TCL1A is not only a useful biomarker for prognostic evaluation in stage II/III CRC patients, but also a promising therapeutic target for improving their clinical outcome.

Clinical Significance of Disseminated Pluripotent Tumor Cell Signature Expression in the Bone Marrow from Patients with Colorectal Cancer

Purpose:

Disseminated tumor cells (DTCs) are critically involved in tumor relapse and survival in several invasive tumors. We previously showed that the ATP-binding cassette (ABC) transporter, ABCB5, is a chemoresistance mediator expressed on specific cell subsets in colorectal cancer (CRC) and other malignancies. This study evaluated the molecular signature expression and its clinical relevance of DTCs in bone marrow from patients with colon cancer.

Methods:

This study included 49 consecutive patients (UICC stage I-IV) that underwent curatively intended or palliative surgery for CRC. We analyzed cells from bone marrow aspirates obtained before surgery and derived from patients that had completed minimally a 5-year follow-up. The gene expression of ABCB5 in comparison to CD133 (molecule for identifying cancer initiating cells), Lgr5 (an intestinal stem cell marker) as well as Cytokeratin (CK) 20 (terminally differentiated tumor cells of epithelial origin) in these cells was evaluated.

Results:

Bone marrow analysis showed differential expression between the analyzed genes. ABCB5 and Lgr5 and to lesser extent CD133 and CK20 genes were significantly expressed in the analyzed cells from bone marrow aspirates while only ABCB5 and Lgr5 were significantly negative associated with tumor progress and overall survival.

Conclusion:

Overexpression of ABCB5 and Lgr5 in bone marrow negatively influenced patient survival pointing to a specific chemo resistant and pluripotent cell subgroup of DTCs in the bone marrow. ABCB5 like Lgr5 positive cells seem to be involved in limited tumor related patient survival, suggesting that ABCB5- and Lgr5-positive cells may be relevant for specific clinical intervention strategies

Genome-wide analysis of DNA copy number alterations in early and advanced gastric cancers

To better understand progressive changes in gastric cancer (GC), early and advanced GCs (EGC and AGC, respectively) were examined for copy number alterations (CNAs). A crypt isolation method was used to isolate DNA from tumors and normal glands in 20 AGCs, and fresh tumor samples were obtained from 45 EGCs. We assessed CNAs for differentiated-type GCs using an Infinium HumanCytoSNP-12v2.1 BeadChip in EGCs and AGCs. The most frequent aberrations in EGC were gains at 8q23.3 (42.2%) and 8q23.2 (40%), and loss of heterozygosity (LOH) at 3p14.2 (24.2%), suggesting that these CNAs were involved in the development of EGC. On the other hand, the highest frequencies of gains in AGC were found at 8q24.21 (65%) and 8q24.3 (60%). The most frequent LOHs in AGC were at 11q24.3-25, 11q23.2-24.1, 11q14.1, and 12p11.21-13.33, whereas that in EGC was at 3p14.2. In addition, regions of copy-neutral LOHs in AGC were detected at 11q21, 11q13.3-14.3, 11q11, 11p13-15.3, 12q21.1, 12q12-13.3 and 5q33.3-35.1. Comparisons of gains in EGC and AGC showed significant differences at 12q22-q23.2, 12q21.33, 11p12, 11p14.1, 12q21.31-32.32, 3p12.3, 3p14.1, 10p15.1, 1q24.2 and 2q12.1. Copy neutral LOHs were significantly higher in AGC than in EGC at 14q32.11-32.33, 14q21.3, 14q11.2, 5q11.2, 5q 13.3, 14q21.1-23.2, 14q13.2-13.3, 5q12.1-12.3, 5q11.1, and 17p13.3. The total lengths of the CNAs were significantly greater in AGC than in EGC. We found that the pattern of CNAs in AGC was quite different from that in EGC. We suggest that increasing numbers of CNAs are associated with disease progression from EGC to AGC. © 2016 Wiley Periodicals, Inc.