Prognostic Value of Cancer Stem Cell Marker ALDH1 Expression in Colorectal Cancer: A Systematic Review and Meta-Analysis

Aldehyde dehydrogenase 1 family: A potential molecule target for diseases

Aldehyde dehydrogenase 1 (ALDH1), a crucial aldehyde metabolizing enzyme, has six family members. The ALDH1 family is expressed in various tissues, with a significant presence in the liver. It plays a momentous role in several pathophysiological processes, including aldehyde detoxification, oxidative stress, and lipid peroxidation. Acetaldehyde detoxification is the fundamental function of the ALDH1 family in participating in vital pathological mechanisms. The ALDH1 family can catalyze retinal to retinoic acid (RA) that is a hormone-signaling molecule and plays a vital role in the development and adult tissues. Furthermore, there is a need for further and broader research on the role of the ALDH1 family as a signaling molecule. The ALDH1 family is widely recognized as a cancer stem cell (CSC) marker and plays a significant role in the proliferation, invasion, metastasis, prognosis, and drug resistance of cancer. The ALDH1 family also participates in other human diseases, such as neurodegenerative diseases, osteoarthritis, diabetes, and atherosclerosis. It can inhibit disease progression by inhibiting/promoting the expression/activity of the ALDH1 family. In this review, we comprehensively analyze the tissue distribution, and functions of the ALDH1 family. Additionally, we review the involvement of the ALDH1 family in diseases, focusing on the underlying pathological mechanisms and briefly talk about the current status and development of ALDH1 family inhibitors. The ALDH1 family presents new possibilities for treating diseases, with both its upstream and downstream pathways serving as promising targets for therapeutic intervention. This offers fresh perspectives for drug development in the field of disease research.

Global research landscape and trends of cancer stem cells from 1997 to 2023: A bibliometric analysis

Cancer stem cells (CSCs) are a subset of cells with self-renewal ability and tumor generating potential. Accumulated evidence has revealed that CSCs were shown to contribute to tumorigenesis, metastasis, recurrence and resistance to chemoradiotherapy. Therefore, CSCs were regarded as promising therapeutic targets in cancer. This study is the first to reveal the development process, research hotspots, and trends of entire CSCs research field through bibliometric methods. All relevant publications on CSCs with more than 100 citations (notable papers) and the 100 most cited papers (top papers) during 1997 to 2023 were extracted and analyzed. Cancer research published the largest number of papers (184 papers). The USA accounted for the most publications (1326 papers). Rich, JN was the author with the most publications (56 papers) and the highest M-index (3.111). The most contributive institution was the University of Texas System (164 papers). Before 2007, research mainly focused on the definition and recognition of CSCs. Between 2007 and 2016, with the emergence of the terms such as "sonic hedgehog," "metabolism," "oxidative phosphorylation," and "epithelial mesenchymal transition," research began to shift toward exploring the mechanisms of CSCs. In 2016, the focus transitioned to the tumor microenvironment and the ecological niches. The analysis of papers published in major journals since 2021 showed that "transcription," "inhibition," and "chemoresistance" emerged as new focused issues. In general, the research focus has gradually shifted from basic biology to clinical transformation. "Tumor microenvironment" and "chemo-resistance" should be given more attention in the future.

MACC1 Regulates LGR5 to Promote Cancer Stem Cell Properties in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. The high mortality is directly associated with metastatic disease, which is thought to be initiated by colon cancer stem cells, according to the cancer stem cell (CSC) model. Consequently, early identification of those patients who are at high risk for metastasis is crucial for improved treatment and patient outcomes. Metastasis-associated in colon cancer 1 (MACC1) is a novel prognostic biomarker for tumor progression and metastasis formation independent of tumor stage. We previously showed an involvement of MACC1 in cancer stemness in the mouse intestine of our MACC1 transgenic mouse models. However, the expression of MACC1 in human CSCs and possible implications remain elusive. Here, we explored the molecular mechanisms by which MACC1 regulates stemness and the CSC-associated invasive phenotype based on patient-derived tumor organoids (PDOs), patient-derived xenografts (PDXs) and human CRC cell lines. We showed that CD44-enriched CSCs from PDO models express significantly higher levels of MACC1 and LGR5 and display higher tumorigenicity in immunocompromised mice. Similarly, RNA sequencing performed on PDO and PDX models demonstrated significantly increased MACC1 expression in ALDH1(+) CSCs, highlighting its involvement in cancer stemness. We further showed the correlation of MACC1 with the CSC markers CD44, NANOG and LGR5 in PDO models as well as established cell lines. Additionally, MACC1 increased stem cell gene expression, clonogenicity and sphere formation. Strikingly, we showed that MACC1 binds as a transcription factor to the LGR5 gene promoter, uncovering the long-known CSC marker LGR5 as a novel essential signaling mediator employed by MACC1 to induce CSC-like properties in human CRC patients. Our in vitro findings were further substantiated by a significant positive correlation of MACC1 with LGR5 in CRC cell lines as well as CRC patient tumors. Taken together, this study indicates that the metastasis inducer MACC1 acts as a cancer stem cell-associated marker. Interventional approaches targeting MACC1 would potentially improve further targeted therapies for colorectal cancer patients to eradicate CSCs and prevent cancer recurrence and distant metastasis formation.

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 Clinical Significance and Prognostic Value of ALDH1 Expression in Non-small Cell Lung Cancer: A Systematic Review and Meta-analysis

BACKGROUND

The results of the association between aldehyde dehydrogenase 1 (ALDH1) expression and prognosis of non-small cell lung cancer (NSCLC) are contradictory. We conducted this meta-analysis to investigate the clinical significance and prognostic value of ALDH1 in NSCLC.

METHODS

The databases PubMed, Web of Science, EMBASE, the Cochrane Library, Wanfang, and CNKI were systematically queried to identify eligible studies. The retrieval time was from database establishment to August 2023. We evaluated the correlation between ALDH1 expression and clinical features of NSCLC by employing odds ratios (ORs) and 95% confidence intervals (95% CIs). In addition, we used hazard ratios (HRs) and 95% CIs to evaluate the role of ALDH1 expression in the prognosis of NSCLC.

RESULTS

Our study included 21 literatures involving 2721 patients. The expression of ALDH1 in NSCLC was higher than that in normal tissues (OR = 6.04, 95% CI: 1.25-29.27, P = 0.026). The expression of ALDH1 was related to TNM stage (OR = 1.81, 95% CI: 1.06-3.09, P = 0.029), tumor grade (OR = 0.29, 95% CI: 0.17-0.48, P < 0.0001), lymph node metastasis (OR = 2.60, 95% CI: 1.52-4.45, P = 0001) and histological subtype (OR = 0.67, 95% CI: 0.52-0.86, P = 0.002). In patients with NSCLC, we found that the over-expression of ALDH1 was significantly associated with poor overall survival (OS) (HR = 1.44, 95% CI: 1.15-1.81, P = 0.002) and disease-free survival (DFS) (HR = 1.74, 95% CI: 1.45-2.10, P < 0.0001).

CONCLUSION

The expression of ALDH1 is closely associated with the clinicopathologic characteristics and prognosis of NSCLC. ALDH1 may serve as a valuable clinical assessment tool and prognostic predictor in NSCLC.

Comprehensive analysis reveals signal and molecular mechanism of mitochondrial energy metabolism pathway in pancreatic cancer

Pancreatic cancer (PAAD) is one of the most malignant tumors with the worst prognosis. The abnormalities in the mitochondrial energy metabolism pathway are intimately correlated with the occurrence and progression of cancer. For the diagnosis and treatment of pancreatic cancer, abnormal genes in the mitochondrial energy metabolism system may offer new targets and biomarkers. In this study, we compared the dysregulated mitochondrial energy metabolism-associated pathways in PAAD based on pancreatic cancer samples in the Cancer Genome Atlas (TCGA) database and normal pancreas samples from the Genotype Tissue Expression project (GTEx) database. Then identified 32 core genes of mitochondrial energy metabolism pathway-related genes (MMRG) were based on the gene set enrichment analysis (GSEA). We found most of these genes were altered among different clinical characteristic groups, and showed significant prognostic value and association with immune infiltration, suggesting critical roles of MMRG involve tumor genesis of PAAD. Therefore, we constructed a four-gene (LDHA, ALDH3B1, ALDH3A1, and ADH6) prognostic biomarker after eliminating redundant factors, and confirming its efficiency and independence. Further analysis indicated the potential therapeutic compounds based on the mitochondrial energy metabolism-associated prognostic biomarker. All of the above analyses dissected the critical role of mitochondrial energy metabolism signaling in pancreatic cancer and gave a better understanding of the clinical intervention of PAAD.

Co-expression of cancer stem cell markers, SALL4/ALDH1A1, is associated with tumor aggressiveness and poor survival in patients with serous ovarian carcinoma

Background

Spalt-like transcription factor 4 (SALL4) and aldehyde dehydrogenase1 family member A1 (ALDH1A1) expressing cells have been characterized as possessing stem cell-like properties known as cancer stem cell marker in serous ovarian carcinoma (SOC).

Methods

The association between SALL4 and ALDH1A1 was observed based on literature review and bioinformatics tools. Therefore, this study aimed to investigate the association between the co-expression of SALL4/ALDH1A1 proteins and clinicopathological parameters and their prognostic value in SOC patients using immunohistochemical staining on tissue microarrays (TMAs). Furthermore, benign tumors and normal tissue samples were compared with the expression of the tumor tissue samples.

Results

Increased co-expression of SALL4/ALDH1A1 was found to be significantly associated with the advanced FIGO stage (P = 0.047), and distant metastasis (P = 0.028). The results of Kaplan–Meier survival analysis indicated significant differences between disease- specific survival (DSS; P = 0.034) or progression-free survival (PFS; P = 0.018) and the patients with high and low co-expression of SALL4/ALDH1A1, respectively. Furthermore, high level co-expression of SALL4/ALDH1A1 was a significant predictor of worse DSS and PFS in the univariate analysis. The data also indicated that the co-expression of SALL4/ALDH1A1 was an independent prognostic factor affecting PFS. Moreover, the co-expression of SALL4/ALDH1A1 added prognostic values of DSS in patients with SOC who had grade III versus grade I in multivariate analysis.

Conclusions

Our data demonstrated that high co-expression of SALL4/ALDH1A1 was found to be significantly associated with tumor aggressiveness and worse DSS or PFS in SOC patients. Therefore, co-expression of SALL4/ALDH1A1 may serve as a potential prognostic biomarker of cancer progression in these cases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00921-x.

Anticancer Activity of Ω-6 Fatty Acids through Increased 4-HNE in Breast Cancer Cells

Simple Summary

Epidemiological evidence suggests that breast cancer risk is lowered by Ω-3 and increased by Ω-6 polyunsaturated fatty acids (PUFAs). Paradoxically, the Ω-6 PUFA metabolite 4-hydroxynonenal (4-HNE) inhibits cancer cell growth. This duality prompted us to study whether arachidonic acid (AA) would enhance doxorubicin (dox) cytotoxicity towards breast cancer cells. We found that supplementing AA or inhibiting 4-HNE metabolism potentiated doxorubicin (dox) toxicity toward Her2-dependent breast cancer but spared myocardial cells. Our results suggest that Ω-6 PUFAs could improve outcomes of dox chemotherapy in Her2-overexpressing breast cancer.

Abstract

Her2-amplified breast cancers resistant to available Her2-targeted therapeutics continue to be a challenge in breast cancer therapy. Dox is the mainstay of chemotherapy of all types of breast cancer, but its usefulness is limited by cumulative cardiotoxicity. Because oxidative stress caused by dox generates the pro-apoptotic Ω-6 PUFA metabolite 4-hydroxynonenal (4-HNE), we surmised that Ω-6 PUFAs would increase the effectiveness of dox chemotherapy. Since the mercapturic acid pathway enzyme RALBP1 (also known as RLIP76 or Rlip) that limits cellular accumulation of 4-HNE also mediates dox resistance, the combination of Ω-6 PUFAs and Rlip depletion could synergistically improve the efficacy of dox. Thus, we studied the effects of the Ω-6 PUFA arachidonic acid (AA) and Rlip knockdown on the antineoplastic activity of dox towards Her2-amplified breast cancer cell lines SK-BR-3, which is sensitive to Her2 inhibitors, and AU565, which is resistant. AA increased lipid peroxidation, 4-HNE generation, apoptosis, cellular dox concentration and dox cytotoxicity in both cell lines while sparing cultured immortalized cardiomyocyte cells. The known functions of Rlip including clathrin-dependent endocytosis and dox efflux were inhibited by AA. Our results support a model in which 4-HNE generated by AA overwhelms the capacity of Rlip to defend against apoptosis caused by dox or 4-HNE. We propose that Ω-6 PUFA supplementation could improve the efficacy of dox or Rlip inhibitors for treating Her2-amplified breast cancer.

Aldehyde dehydrogenase 3B2 promotes the proliferation and invasion of cholangiocarcinoma by increasing Integrin Beta 1 expression

Aldehyde dehydrogenases (ALDHs) play an essential role in regulating malignant tumor progression; however, their role in cholangiocarcinoma (CCA) has not been elucidated. We analyzed the expression of ALDHs in 8 paired tumor and peritumor perihilar cholangiocarcinoma (pCCA) tissues and found that ALDH3B1 and ALDH3B2 were upregulated in tumor tissues. Further survival analysis in intrahepatic cholangiocarcinoma (iCCA, n = 27), pCCA (n = 87) and distal cholangiocarcinoma (dCCA, n = 80) cohorts have revealed that ALDH3B2 was a prognostic factor of CCA and was an independent prognostic factor of iCCA and pCCA. ALDH3B2 expression was associated with serum CEA in iCCA and dCCA, associated with tumor T stage, M stage, neural invasion and serum CA19-9 in pCCA. In two cholangiocarcinoma cell lines, overexpression of ALDH3B2 promoted cell proliferation and clone formation by promoting the G1/S phase transition. Knockdown of ALDH3B2 inhibited cell migration, invasion, and EMT in vitro, and restrained tumor metastasis in vivo. Patients with high expression of ALDH3B2 also have high expression of ITGB1 in iCCA, pCCA, and dCCA at both mRNA and protein levels. Knockdown of ALDH3B2 downregulated the expression of ITGB1 and inhibited the phosphorylation level of c-Jun, p38, and ERK. Meanwhile, knockdown of ITGB1 inhibited the promoting effect of ALDH3B2 overexpression on cell proliferation, migration, and invasion. ITGB1 is also a prognostic factor of iCCA, pCCA, and dCCA and double-positive expression of ITGB1 and ALDH3B2 exhibits better performance in predicting patient prognosis. In conclusion, ALDH3B2 promotes tumor proliferation and metastasis in CCA by regulating the expression of ITGB1 and upregulating its downstream signaling pathway. The double-positive expression of ITGB1 and ALDH3B2 serves as a better prognostic biomarker of CCA.

FBXW11 contributes to stem-cell-like features and liver metastasis through regulating HIC1-mediated SIRT1 transcription in colorectal cancer

Colorectal tumorigenesis is a heterogeneous disease driven by multiple genetic and epigenetic alterations. F-box and WD repeat domain containing 11 (FBXW11) is a member of the F-box protein family that regulates the ubiquitination of key factors associated with tumor growth and aggressiveness. Our study aimed to explore the role of FBXW11 in the development and metastasis of colorectal cancer (CRC). FBXW11 was overexpressed in colorectal tumor tissues and its overexpression was associated with a poor prognosis of CRC patients. The upregulation of FBXW11 not only promoted cell proliferation, invasion, and migration, but also contributed to maintaining stem-cell features in colorectal tumor cells. Further analysis revealed that FBXW11 targeted hypermethylated in cancer 1 (HIC1) and reduced its stability in CRC cells through ubiquitination. Moreover, the expression of sirtuin 1 (SIRT1), a deacetylase in tumor cells was upregulated by FBXW11 via regulating HIC1 expression. The mouse xenograft models of CRC confirmed that FBXW11 knockdown impeded colorectal tumor growth and liver metastasis in vivo. In summary, our study identified FBXW11 as an oncogenic factor that contributed to stem-cell-like properties and liver metastasis in CRC via regulating HIC1-mediated SIRT1 expression. These results provide a rationale for the development of FBXW11-targeting drugs for CRC patients.

Boman B. Retinoids in Treatment of Colorectal Cancer

Retinoids are vitamin A metabolites best known for their role in embryonic development. Indeed, retinoid acid (RA) signaling plays a key role in regulating the development of the embryo body-plan by controlling embryonic stem cells (SCs). Retinoids function through their ability to induce cellular differentiation. Mutations in RA signaling pathway genes occur in most human cancers. The classic example is the chromosomal translocation involving RA receptor alpha in acute promyelocytic leukemia (APL). Because all-trans retinoic acid (ATRA) is a highly effective and often curative treatment for APL patients, determining if retinoids are efficacious for other cancer types is imperative. We review the current research on retinoids in colorectal cancer (CRC) and provide bioinformatics analyses of RA signaling. Our results show that most RA pathway genes are overexpressed and often mutated in CRC. Moreover, aberrant expression of many RA signaling proteins predicts decreased CRC patient survival. We also review aldehyde dehydrogenase (ALDH) expression in CRC because ALDH is a key enzyme in RA signaling, which regulates colonic SCs. Further investigation of RA signaling mechanisms that regulate colon SCs and how dysregulation contributes to the SC overpopulation that drives CRC growth should provide insight into strategies for designing new SC-targeted therapies for CRC.

ALDH1 expression predicts progression of premalignant lesions to cancer in Type I endometrial carcinomas

In type 1 endometrial cancer, unopposed estrogen stimulation is thought to lead to endometrial hyperplasia which precedes malignant progression. Recent data from our group and others suggest that ALDH activity mediates stemness in endometrial cancer, but while aldehyde dehydrogenase 1 (ALDH1) has been suggested as a putative cancer stem cell marker in several cancer types, its clinical and prognostic value in endometrial cancer remains debated. The aim of this study was to investigate the clinical value of ALDH1 expression in endometrial hyperplasia and to determine its ability to predict progression to endometrial cancer. Interrogation of the TCGA database revealed upregulation of several isoforms in endometrial cancer, of which the ALDH1 isoforms collectively constituted the largest group. To translate its expression, a tissue microarray was previously constructed which contained a wide sampling of benign and malignant endometrial samples. The array contained a metachronous cohort of samples from individuals who either developed or did not develop endometrial cancer. Immunohistochemical staining was used to determine the intensity and frequency of ALDH1 expression. While benign proliferative and secretory endometrium showed very low levels of ALDH1, slightly higher expression was observed within the stratum basalis. In disease progression, cytoplasmic ALDH1 expression showed a step-wise increase between endometrial hyperplasia, atypical hyperplasia, and endometrial cancer. ALDH1 was also shown to be an early predictor of EC development, suggesting that it can serve as an independent prognostic indicator of patients with endometrial hyperplasia with or without atypia who would progress to cancer (p = 0.012).

The antioxidant response in Barrett's tumorigenesis: A double-edged sword

Esophageal adenocarcinoma (EAC) is the dominant form of esophageal malignancies in the United States and other industrialized countries. The incidence of EAC has been rising rapidly during the past four decades. Barrett's esophagus (BE) is the main precancerous condition for EAC, where a metaplastic columnar epithelium replaces normal squamous mucosa of the lower esophagus. The primary risk factor for BE and EAC are chronic gastroesophageal reflux disease (GERD), obesity and smoking. During the BE-dysplasia-EAC sequence, esophageal cells are under a tremendous burden of accumulating reactive oxygen species (ROS) and oxidative stress. While normal cells have intact antioxidant machinery to maintain a balanced anti-tumorigenic physiological response, the antioxidant capacity is compromised in neoplastic cells with a pro-tumorigenic development antioxidant response. The accumulation of ROS, during the neoplastic progression of the GERD-BE-EAC sequence, induces DNA damage, lipid peroxidation and protein oxidation. Neoplastic cells adapt to oxidative stress by developing a pro-tumorigenic antioxidant response that keeps oxidative damage below lethal levels while promoting tumorigenesis, progression, and resistance to therapy. In this review, we will summarize the recent findings on oxidative stress in tumorigenesis in the context of the GERD-BE-EAC process. We will discuss how EAC cells adapt to increased ROS. We will review APE1 and NRF2 signaling mechanisms in the context of EAC. Finally, we will discuss the potential clinical significance of applying antioxidants or NRF2 activators as chemoprevention and NRF2 inhibitors in treating EAC patients.

Enrichment of cancer-initiating cells from colon cancer cells through porous polymeric membranes by a membrane filtration method

Cancer-initiating cells (CICs) or cancer stem cells (CSCs) are primarily responsible for tumor initiation, growth, and metastasis and represent a few percent of the total tumor cell population. We designed a membrane filtration protocol to enrich CICs (CSCs) from the LoVo colon cancer cell line via nylon mesh filter membranes with 11 and 20 μm pore sizes and poly(lactide-co-glycolic acid)/silk screen (PLGA/silk screen) porous membranes (pore sizes of 20-30 μm). The colon cancer cell solution was filtered through the membranes to obtain a permeate solution. Subsequently, the cell culture medium was filtered through the membranes to collect the recovery solution where the cells attached to the membranes were rinsed off into the recovery solution. Then, the membranes were cultivated in the cultivation medium to collect the migrated cells from the membranes. The cells migrated from any membrane had higher expression of the CSC surface markers CD44 and CD133, had higher colony formation levels, and produced more carcinoembryonic antigen (CEA) than the colon cancer cells cultivated on conventional tissue culture plates (control). We established a method to enrich the CICs (CSCs) of colon cancer cells from migrated cells through porous polymeric membranes by the membrane filtration protocol developed in this study.

Cancer Stem Cells-Key Players in Tumor Relapse

Tumor relapse and treatment failure are unfortunately common events for cancer patients, thus often rendering cancer an uncurable disease. Cancer stem cells (CSCs) are a subset of cancer cells endowed with tumor-initiating and self-renewal capacity, as well as with high adaptive abilities. Altogether, these features contribute to CSC survival after one or multiple therapeutic approaches, thus leading to treatment failure and tumor progression/relapse. Thus, elucidating the molecular mechanisms associated with stemness-driven resistance is crucial for the development of more effective drugs and durable responses. This review will highlight the mechanisms exploited by CSCs to overcome different therapeutic strategies, from chemo- and radiotherapies to targeted therapies and immunotherapies, shedding light on their plasticity as an insidious trait responsible for their adaptation/escape. Finally, novel CSC-specific approaches will be described, providing evidence of their preclinical and clinical applications.

Clinicopathological Significance of Tumor Stem Cell Markers ALDH1 and CD133 in Colorectal Carcinoma

Background & Objective:

Colorectal cancer (CRC) is the third most common cancer worldwide with a high mortality rate. The main causes of death in patients are recurrence and metastasis which are mainly attributed to the small subpopulation of cells within tumors called cancer stem cells (CSCs). This study aimed to evaluate the correlation between the expression of ALDH1 and CD133 as CSC associated markers and clinicopathological characteristics in CRC.

Methods:

In this cross-sectional study, a total of 483 CRC tumor samples were immunohistochemically stained for detection of CD133 and ALDH1 markers. Correlations of marker expression with clinicopathological factors were also evaluated.

Results:

There was a significant correlation between the luminal intensity of CD133 and neural invasion (P=0.05) and between the cytoplasmic intensity of CD133 and metastasis (P=0.05). In terms of H-score, a positive significant relation was observed between cytoplasmic expression of CD133 and lymph node (P=0.02), neural (P=0.04) and vascular invasion (P=0.02). The ALDH1 cytoplasmic expression showed a significant correlation with tumor size (P=0.001).

Conclusion:

Our findings showed that increased expression of CD133 and ALDH1 is associated with tumor progression and worse outcomes in CRC patients. These markers can be good candidates for localized targeting of CSCs using antibodies. Future researches need to be improved approaches for early detection of CRC, and treatment monitoring for CRC and other cancers.

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.

The SOX9-Aldehyde Dehydrogenase Axis Determines Resistance to Chemotherapy in Non-Small-Cell Lung Cancer

Chemotherapy resistance and tumor relapse are the major contributors to low patient survival, and both have been largely attributed to cancer stem-like cells (CSCs) or tumor-initiating cells (TICs). Moreover, most conventional therapies are not effective against CSCs, which necessitates the discovery of CSC-specific biomarkers and drug targets. Here, we demonstrated that the embryonic transcription factor SOX9 is an important regulator of acquired chemoresistance in non-small-cell lung cancer (NSCLC). Our results show that SOX9 expression is elevated in NSCLC cells after treatment with the chemotherapeutic cisplatin and that overexpression of SOX9 correlates with worse overall survival in lung cancer patients. We further demonstrated that SOX9 knockdown increases cellular sensitivity to cisplatin, whereas its overexpression promotes drug resistance. Moreover, this transcription factor promotes the stem-like properties of NSCLC cells and increases their aldehyde dehydrogenase (ALDH) activity, which was identified to be the key mechanism of SOX9-induced chemoresistance. Finally, we showed that ALDH1A1 is a direct transcriptional target of SOX9, based on chromatin immunoprecipitation and luciferase reporter assays. Taken together, our novel findings on the role of the SOX9-ALDH axis support the use of this CSC regulator as a prognostic marker of cancer chemoresistance and as a potential drug target for CSC therapy.

The Prognostic Value of Cancer Stem Cell Markers (Notch1, ALDH1, and CD44) in Primary Colorectal Carcinoma

BACKGROUND

Cancer stem cells proved to have a vital role in cell migration, invasion, metastasis, and treatment resistance of colorectal cancer (CRC) that subsequently lead to poor clinical outcomes. These stem cells may be a novel therapeutic target for the management of CRC progression. Signals of the Notch-1 pathway are responsible for acquisition of stem cell characters. ALDH1 and CD44 are usually detected in stem cells in colorectal cancer.

AIM

The aims of this work are to evaluate the immunohistochemical expression of cancer stem cell markers ALDH1, Notch1, and CD44 in colorectal cancer and investigate their correlation with clinicopathological characters and patient survival.

METHODS

Paraffin-embedded specimens of 70 patients with primary colorectal carcinoma were analyzed for Notch 1, ALDH1, and CD44 expressions by immunohistochemistry.

RESULTS

Notch1 was mainly located in the cytoplasm of CRC tissues, rarely expressed in adjacent normal tissues. A highly statistically significant relationship was found between grading, lymphovascular invasion, the degree of lymphocytic infiltration, peritumoral budding, lymph node ratio, lymph node metastasis, and Notch1 expression (p < 0.001). There was a highly statistically significant relationship found between AJCC stage and Notch1 expression (p < 0.001). CD44 was mainly located in the cell membrane of CRC tissues. A highly statistically significant relationship was found between grading (p = 0.006), lymphovascular invasion, the degree of lymphocytic infiltration, peritumoral budding, lymph node metastasis, lymph node ratio, and CD44 expression (p < 0.001). There was a highly statistically significant relationship found between AJCC stage and CD44 expression (p < 0.001). ALDH1 was detected in the cytoplasm of the CRC tissue. A highly statistically significant relationship was found between grading, lymphovascular invasion, the degree of lymphocytic infiltration, peritumoral budding, lymph node metastasis, lymph node ratio, and ALDH1 expression (p < 0.001). There was a highly statistically significant relationship found between AJCC stage and ALDH1 expression (p < 0.001). There is a highly statistically significant direct correlation between Notch1, CD44 expression, and ALDH1 expression (p < 0.001).

CONCLUSIONS

There is a substantial correlation between Notch 1, ALDH1, and CD44 as cancer stem cell markers and lymph node metastasis, advanced stage and tumor recurrence in colorectal carcinoma.

CONCLUSION

Expression of stem cell markers ALDH1, Notch1, and CD44 correlates with poor prognosis in a CRC and represents an independent prognostic factor. They are associated with a feature of epithelial-mesenchymal transition evidenced by their association with high tumor burden.

Mithramycin A Inhibits Colorectal Cancer Growth by Targeting Cancer Stem Cells

The pivotal role of cancer initiating stem cells (CSCs) in tumor initiation, growth, metastasis and drug resistance has led to the postulation of a 'total cancer therapy' paradigm, which involves targeting both cancer cells and CSCs for effective therapy. However, the progress in identifying drugs for total cancer therapy has been limited. Herein, we show for the first time that mithramycin A (Mit-A) can successfully inhibit CSC proliferation, in addition to inhibiting bulk cancer cells in a model of colorectal cancer (CRC), the second leading cause of death among men and women in the United States. To this end, a polymeric nanofiber scaffold culture system was established to develop 3D tumor organoids (tumoroids) from CRC cell lines such as HT29, HCT116, KM12, CT26 and MC38 as well as ex vivo mouse tumors. These tumoroids possessed increased expression of CSC markers and transcription factors, expanded the number of CSCs in culture and increased CSC functional properties measured by aldehyde dehydrogenase activity. Screening of an NCI library of FDA approved drugs led to the identification of Mit-A as a potential total cancer therapy drug. In both sphere and tumoroid culture, Mit-A inhibits cancer growth by reducing the expression of cancer stemness markers. In addition, Mit-A inhibits the expression of SP1, a previously known target in CRCs. Moreover, Mit-A significantly reduces growth of tumoroids in ex vivo cultures and CRC tumor growth in vivo. Finally, a dose-dependent treatment on CRC cells indicate that Mit-A significantly induces the cell death and PARP-cleavage of both CSC and non-CSC cells. Taken together the results of these in vitro, ex vivo and in vivo studies lead to the inference that Mit-A is a promising drug candidate for total cancer therapy of CRCs.

Cancer stem cells in esophageal squamous cell cancer

Cancer stem cells (CSCs) are hypothesized to govern the origin, progression, drug resistance, recurrence and metastasis of human cancer. CSCs have been identified in nearly all types of human cancer, including esophageal squamous cell cancer (ESCC). Four major methods are typically used to isolate or enrich CSCs, including: i) fluorescence-activated cell sorting or magnetic-activated cell sorting using cell-specific surface markers; ii) stem cell markers, including aldehyde dehydrogenase 1 family member A1; iii) side population cell phenotype markers; and iv) microsphere culture methods. ESCC stem cells have been identified using a number of these methods. An increasing number of stem cell signatures and pathways have been identified, which have assisted in the clarification of molecular mechanisms that regulate the stemness of ESCC stem cells. Certain viruses, such as human papillomavirus and hepatitis B virus, are also considered to be important in the formation of CSCs, and there is a crosstalk between stemness and viruses-associated genes/pathways, which may suggest a potential therapeutic strategy for the eradication of CSCs. In the present review, findings are summarized along these lines of inquiry.

P53-R273H mutation enhances colorectal cancer stemness through regulating specific lncRNAs

Background

TP53 is one of the most frequently mutated genes among all cancer types, and TP53 mutants occur more than 60% in colorectal cancer (CRC). Among all mutants, there are three hot spots, including p53-R175H, p53-R248W and p53-R273H. Emerging evidence attributes cancer carcinogenesis to cancer stem cells (CSCs). Long noncoding RNAs (lncRNAs) play crucial roles in maintaining the stemness of CSCs. However, it is unknown if mutant p53-regulated lncRNAs are implicated in the maintenance of CSC stemness.

Methods

RNA-sequencing (RNA-seq) and ChIP-sequencing (ChIP-seq) were used to trace the lncRNA network regulated by p53-R273H in HCT116 endogenous p53 point mutant spheroid cells generated by the somatic cell knock-in method. RT-qPCR was used to detect lncRNA expression patterns, verifying the bioinformatics analysis. Transwell, spheroid formation, fluorescence activated cell sorter (FACS), xenograft nude mouse model, tumor frequency assessed by extreme limiting dilution analysis (ELDA), Western blot assays and chemoresistance analysis were performed to elucidate the functions and possible mechanism of lnc273–31 and lnc273–34 in cancer stem cells.

Results

p53-R273H exhibited more characteristics of CSC than p53-R175H and p53-R248W. RNA-seq profiling identified 37 up regulated and 4 down regulated differentially expressed lncRNAs regulated by p53-R273H. Combined with ChIP-seq profiling, we further verified two lncRNAs, named as lnc273–31 and lnc273–34, were essential in the maintenance of CSC stemness. Further investigation illustrated that lnc273–31 or lnc273–34 depletion dramatically diminished colorectal cancer migration, invasion, cancer stem cell self-renewal and chemoresistance in vitro. Moreover, the absence of lnc273–31 or lnc273–34 dramatically delayed cancer initiation and tumorigenic cell frequency in vivo. Also, lnc273–31 and lnc273–34 have an impact on epithelial-to mesenchymal transition (EMT). Finally, lnc273–31 and lnc273–34 were significantly highly expressed in CRC tissues with p53-R273H mutation compared to those with wildtype p53.

Conclusions

The present study unveiled a high-confidence set of lncRNAs regulated by p53-R273H specific in colorectal CSCs. Furthermore, we demonstrated that two of them, lnc273–31 and lnc273–34, were required for colorectal CSC self-renewal, tumor propagation and chemoresistance. Also, the expression of these two lncRNAs augmented in colorectal cancer patient samples with p53-R273H mutation. These two lncRNAs may serve as promising predictors for patients with p53-R273H mutation and are vital for chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1375-9) contains supplementary material, which is available to authorized users.

Radiogenomics-based cancer prognosis in colorectal cancer

Radiogenomics aims at investigating the relationship between imaging radiomic features and gene expression alterations. This study addressed the potential prognostic complementary value of contrast enhanced computed tomography (CE-CT) radiomic features and gene expression data in primary colorectal cancers (CRC). Sixty-four patients underwent CT scans and radiomic features were extracted from the delineated tumor volume. Gene expression analysis of a small set of genes, previously identified as relevant for CRC, was conducted on surgical samples from the same tumors. The relationships between radiomic and gene expression data was assessed using the Kruskal–Wallis test. Multiple testing was not performed, as this was a pilot study. Cox regression was used to identify variables related to overall survival (OS) and progression free survival (PFS). ABCC2 gene expression was correlated with N (p = 0.016) and M stages (p = 0.022). Expression changes of ABCC2, CD166, CDKNV1 and INHBB genes exhibited significant correlations with some radiomic features. OS was associated with Ratio 3D Surface/volume (p = 0.022) and ALDH1A1 expression (p = 0.042), whereas clinical stage (p = 0.004), ABCC2 expression (p = 0.035), and Entropy_{GLCM_E} (p = 0.0031), were prognostic factors for PFS. Combining CE-CT radiomics with gene expression analysis and histopathological examination of primary CRC could provide higher prognostic stratification power, leading to improved patient management.

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

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

Cell biological profiling of reprogrammed cancer stem cell-like colon cancer cells maintained in culture

Cancer stem cells (CSCs) are specific targets for therapeutic applications, but the rarity of CSCs within tumors makes the isolation of CSCs difficult. To overcome these problems, we generated CSCs in vitro using established reprogramming techniques. We transduced four previously established reprogramming factors, Oct3/4, Sox2, Klf4, and L-myc, into the colon cancer cell lines LoVo and OUMS-23, and investigated the biological characteristics of these lines. Tra-1-60+ cells were obtained from reprogrammed induced pluripotent stem (iPS) cell-like colonies and showed CSC properties, including colony formation, maintenance of colonies by repeated passages, and feeder cell dependency, as well as increased expressions of CSC markers such as CD133 and ALDH1. The CSC-like cells showed increased chemoresistance to 5-fluorouracil and elevated tumorigenicity upon transplantation into kidneys of immune-deficient mice. These tumors shifted to a poorly differentiated stage with many atypical cells, cytoplasmic mucin, and focal papillary components, with demonstrated dedifferentiation. The principal component analysis from DNA microarrays showed that though both cell lines moved to iPS cells after reprogramming, they were not completely identical to iPS cells. Significantly elevated gene expression of Decorin and CD90 was observed in CSC-like cells. Together, these results show that reprogramming of cancer cells produced not pluripotent stem cells but CSC-like cells, and these findings will provide biological information about genuine CSCs and help establish new CSC-targeted therapies.

ALDH1A3 upregulation and spontaneous metastasis formation is associated with acquired chemoresistance in colorectal cancer cells

Background

Efficiency of colorectal carcinoma treatment by chemotherapy is diminished as the resistance develops over time in patients. The same holds true for 5-fluorouracil, the drug used in first line chemotherapy of colorectal carcinoma.

Methods

Chemoresistant derivative of HT-29 cells was prepared by long-term culturing in increasing concentration of 5-fluorouracil. Cells were characterized by viability assays, flow cytometry, gene expression arrays and kinetic imaging. Immunomagnetic separation was used for isolation of subpopulations positive for cancer stem cells-related surface markers. Aldehyde dehydrogenase expression was attenuated by siRNA. In vivo studies were performed on SCID/bg mice.

Results

The prepared chemoresistant cell line labeled as HT-29/EGFP/FUR is assigned with different morphology, decreased proliferation rate and 135-fold increased IC₅₀ value for 5-fluorouracil in comparison to parental counterparts HT-29/EGFP. The capability of chemoresistant cells to form tumor xenografts, when injected subcutaneously into SCID/bg mice, was strongly compromised, however, they formed distant metastases in mouse lungs spontaneously. Derived cells preserved their resistance in vitro and in vivo even without the 5-fluorouracil selection pressure. More importantly, they were resistant to cisplatin, oxaliplatin and cyclophosphamide exhibiting high cross-resistance along with alterations in expression of cancer-stem cell markers such as CD133, CD166, CD24, CD26, CXCR4, CD271 and CD274. We also detected increased aldehyde dehydrogenase (ALDH) activity associated with overexpression of specific ALDH isoform 1A3. Its inhibition by siRNA approach partially sensitized cells to various agents, thus linking for the first time the ALDH1A3 and chemoresistance in colorectal cancer.

Conclusion

Our study demonstrated that acquired chemoresistance goes along with metastatic and migratory phenotype and can be accompanied with increased activity of aldehyde dehydrogenase. We describe here the valuable model to study molecular link between resistance to chemotherapy and metastatic dissemination.

ATP-binding cassette member B5 (ABCB5) promotes tumor cell invasiveness in human colorectal cancer

ABC member B5 (ABCB5) mediates multidrug resistance (MDR) in diverse malignancies and confers clinically relevant 5-fluorouracil resistance to CD133-expressing cancer stem cells in human colorectal cancer (CRC). Because of its recently identified roles in normal stem cell maintenance, we hypothesized that ABCB5 might also serve MDR-independent functions in CRC. Here, in a prospective clinical study of 142 CRC patients, we found that ABCB5 mRNA transcripts previously reported not to be significantly expressed in healthy peripheral blood mononuclear cells are significantly enriched in patient peripheral blood specimens compared with non-CRC controls and correlate with CRC disease progression. In human-to-mouse CRC tumor xenotransplantation models that exhibited circulating tumor mRNA, we observed that cancer-specific ABCB5 knockdown significantly reduced detection of these transcripts, suggesting that the knockdown inhibited tumor invasiveness. Mechanistically, this effect was associated with inhibition of expression and downstream signaling of AXL receptor tyrosine kinase (AXL), a proinvasive molecule herein shown to be produced by ABCB5-positive CRC cells. Importantly, rescue of AXL expression in ABCB5-knockdown CRC tumor cells restored tumor-specific transcript detection in the peripheral blood of xenograft recipients, indicating that ABCB5 regulates CRC invasiveness, at least in part, by enhancing AXL signaling. Our results implicate ABCB5 as a critical determinant of CRC invasiveness and suggest that ABCB5 blockade might represent a strategy in CRC therapy, even independently of ABCB5's function as an MDR mediator.

Precision Medicine for CRC Patients in the Veteran Population: State-of-the-Art, Challenges and Research Directions

Colorectal cancer (CRC) accounts for ~9% of all cancers in the Veteran population, a fact which has focused a great deal of the attention of the VA's research and development efforts. A field-based meeting of CRC experts was convened to discuss both challenges and opportunities in precision medicine for CRC. This group, designated as the VA Colorectal Cancer Cell-genomics Consortium (VA4C), discussed advances in CRC biology, biomarkers, and imaging for early detection and prevention. There was also a discussion of precision treatment involving fluorescence-guided surgery, targeted chemotherapies and immunotherapies, and personalized cancer treatment approaches. The overarching goal was to identify modalities that might ultimately lead to personalized cancer diagnosis and treatment. This review summarizes the findings of this VA field-based meeting, in which much of the current knowledge on CRC prescreening and treatment was discussed. It was concluded that there is a need and an opportunity to identify new targets for both the prevention of CRC and the development of effective therapies for advanced disease. Also, developing methods integrating genomic testing with tumoroid-based clinical drug response might lead to more accurate diagnosis and prognostication and more effective personalized treatment of CRC.

Colorectal cancer liver metastases organoids retain characteristics of original tumor and acquire chemotherapy resistance

BACKGROUND

Colorectal cancer (CRC) liver metastasis is highly unfavorable for patient outcome and is a leading cause of cancer-related death. Pre-clinical research of CRC liver metastasis predominately utilizes CRC cell lines grown in tissue culture. Here, we demonstrate that CRC liver metastases organoids derived from human specimens recapitulate some aspects of human disease.

METHODS

Human CRC liver metastases pathological specimens were obtained following patient consent. Tumor disaggregates were plated and organoids were allowed to expand. CRC markers were identified by immunofluorescence. Stem cell genes were analysed by QPCR and flow cytometry. Response to drug therapy was quantified using time-lapse imaging and MATLAB analysis.

RESULTS

Organoids showed global expression of the epithelial marker, EpCAM and the adenocarcinoma marker, CEA CAM1. Flow cytometry analysis demonstrated that organoids express the stem cell surface markers CD24 and CD44. Finally, we demonstrated that CRC liver metastases organoids acquire chemotherapy resistance and can be utilized as surrogates for drug testing.

CONCLUSION

These data demonstrate that CRC liver metastases organoids recapitulate some aspects of human disease and may provide an invaluable resource for investigating novel drug therapies, chemotherapy resistance and mechanism of metastasis.

Molecular profiling of ALDH1+ colorectal cancer stem cells reveals preferential activation of MAPK, FAK, and oxidative stress pro-survival signalling pathways

Tumour heterogeneity leads to variable clinical response and inaccurate diagnostic and prognostic assessment. Cancer stem cells (CSCs) represent a subpopulation responsible for invasion, metastasis, therapeutic resistance, and recurrence in many human cancer types. However, the true identity of colorectal cancer (CRC) SCs remains elusive. Here, we aimed to characterize and define the gene expression portrait of CSCs in CRC-model SW403 cells. We found that ALDH⁺ positive cells are clonogenic and highly proliferative; their global gene expression profiling-based molecular signature revealed gene enrichment related to DNA damage, MAPK, FAK, oxidative stress response, and Wnt signalling. ALDH⁺ cells showed enhanced ROS stress resistance, whereas MAPK/FAK pathway pharmacologic inhibition limited their survival. Conversely, 5-fluorouracil increased the ALDH⁺ cell fraction among the SW403, HCT116 and SW620 CRC models. Notably, analysis of ALDH1A1 and POU5F1 expression levels in cohorts of 462 or 420 patients for overall (OS) or disease-free (DFS) survival, respectively, obtained from the Cancer Genome Atlas CRC dataset, revealed strong association between elevated expression and poor OS (p = 0.006) and poor DFS (p = 0.05), thus implicating ALDH1A1 and POU5F1 in CRC prognosis. Our data reveal distinct molecular signature of ALDH⁺ CSCs in CRC and suggest pathways relevant for successful targeted therapies and management of CRC.

CD133 expression predicts post-operative recurrence in patients with colon cancer with peritoneal metastasis

Despite extensive research on cancer stem cells in colorectal cancer, the impact of stem cell markers on patient survival remains unclear, particularly in those with distant metastasis. In this study, we focused on colon cancer with peritoneal metastasis and investigated the association between the expression of CD133, aldehyde dehydrogenase-1 (ALDH1) and leucine-rich repeating G-protein coupled receptor-5 (Lgr5), and disease prognosis. Putative stem cell marker expression was immunohistochemically evaluated in samples from 142 primary tumours and 75 peritoneal nodules. The associations between the expression of these markers and clinicopathological characteristics, overall survival and disease-free survival were analysed. The expression of CD133, ALDH1 and Lgr5 was found to be positive in 55.6, 47.2 and 78.9% of the primary tumour samples, respectively. While their expression was not associated with overall survival, disease-free survival was significantly worse in the CD133‑negative group (36.1 vs. 13.7%, P=0.041). Multivariable analysis confirmed that a negative CD133 expression was an independent risk factor for a reduced disease-free survival (P=0.005). Furthermore, the benefit of systemic chemotherapy was significantly greater in the CD133-negative group (P=0.039). On the whole, our data indicated that patients with colon cancer with CD133-negative expression had a reduced disease-free survival. Thus, we propose that CD133 expression may be a useful clinical biomarker in the treatment of colon cancer with peritoneal metastasis.

Suppression of cancer stemness by upregulating Ligand-of-Numb protein X1 in colorectal carcinoma

Cancer stem-like cells (CSCs) have been reported to play major roles in tumorigenesis, tumor relapse, and metastasis after therapy against colorectal carcinoma (CRC). Therefore, identification of colorectal CSC regulators could provide promising targets for CRC. Ligand-of-Numb protein X1 (LNX1) is one E3 ubiquitin ligase which mediates the ubiquitination and degradation of Numb. Although several studies indicate LNX1 could be a potential suppressor of cancer diseases, the functions of LNX1 in mediating cancer stemness remain poorly understood. In this study, LNX1 was identified as a negative regulator of cancer stemness in CRC, which was downregulated in colonospheres or side population (SP) cells. Furthermore, the coxsackievirus and adenovirus receptor (CXADR) was found to be one critical downstream mediator of cancer stemness regulated by LNX1. Interestingly, the anti-breast cancer drug tamoxifen was found to be an agonist of LNX1 and suppress cancer stemness in CRC. In sum, this study provided the evidences that LNX1 signaling plays important roles in regulating the stemness of colon cancer cells.

Cancer stem cell-related gene expression as a potential biomarker of response for first-in-class imipridone ONC201 in solid tumors

Cancer stem cells (CSCs) correlate with recurrence, metastasis and poor survival in clinical studies. Encouraging results from clinical trials of CSC inhibitors have further validated CSCs as therapeutic targets. ONC201 is a first-in-class small molecule imipridone in Phase I/II clinical trials for advanced cancer. We have previously shown that ONC201 targets self-renewing, chemotherapy-resistant colorectal CSCs via Akt/ERK inhibition and DR5/TRAIL induction. In this study, we demonstrate that the anti-CSC effects of ONC201 involve early changes in stem cell-related gene expression prior to tumor cell death induction. A targeted network analysis of gene expression profiles in colorectal cancer cells revealed that ONC201 downregulates stem cell pathways such as Wnt signaling and modulates genes (ID1, ID2, ID3 and ALDH7A1) known to regulate self-renewal in colorectal, prostate cancer and glioblastoma. ONC201-mediated changes in CSC-related gene expression were validated at the RNA and protein level for each tumor type. Accordingly, we observed inhibition of self-renewal and CSC markers in prostate cancer cell lines and patient-derived glioblastoma cells upon ONC201 treatment. Interestingly, ONC201-mediated CSC depletion does not occur in colorectal cancer cells with acquired resistance to ONC201. Finally, we observed that basal expression of CSC-related genes (ID1, CD44, HES7 and TCF3) significantly correlate with ONC201 efficacy in >1000 cancer cell lines and combining the expression of multiple genes leads to a stronger overall prediction. These proof-of-concept studies provide a rationale for testing CSC expression at the RNA and protein level as a predictive and pharmacodynamic biomarker of ONC201 response in ongoing clinical studies.

Aldehyde dehydrogenase 1 expression is correlated with poor prognosis in breast cancer

Breast cancer (BC) is one of the most common cancers worldwide, and is a major cause of death in women. Aldehyde dehydrogenase 1 (ALDH1) is a marker of stem cells and cancer stem cells, and its activity correlates with the outcome of various tumors, including BC. This study aimed to analyze the relationship between ALDH1 expression and clinicopathological characters in BC and the prognostic significance of ALDH1.We used quantitative reverse-transcription PCR (qRT-PCR) to detect ALDHA1 mRNA levels in 25 fresh frozen BC samples and matched noncancerous samples. Immunohistochemistry on tissue microarrays was used to analyze protein expression in 137 paraffin-embedded BC tissues and corresponding noncancerous tissues. STATA 16.0 software was used for statistical analysis.The results suggested that levels of both ALDH1 mRNA and protein in BC were significantly higher than in corresponding adjacent breast samples (3.856 ± 0.3442 vs 1.385 ± 0.1534, P < .001; 52.6% vs 25.5%, P < .001, respectively). ALDH1 protein expression was also significantly associated with histological grade (P  =  .017), tumor size (P  =  .017), and tumor-node-metastasis (TNM) stage (P  =  .038). Multivariate analysis using the Cox regression model demonstrated that ALDH1 expression (P  =  .024), molecular typing (P  =  .046), and TNM classification (P  =  .034) were independent predictive factors for the outcome of BC. Kaplan-Meier analysis and the log-rank test indicated that patients with high ALDH1 expression, triple-negative BC, and advanced TNM stage had a reduced overall survival time.These data suggest that ALDH1 could be used as a prognostic factor for BC and may provide a useful therapeutic target in the treatment of BC.

Exploring the clonal evolution of CD133/aldehyde-dehydrogenase-1 (ALDH1)-positive cancer stem-like cells from primary to recurrent high-grade serous ovarian cancer (HGSOC). A study of the Ovarian Cancer Therapy-Innovative Models Prolong Survival (OCTIPS) Consortium

BACKGROUND

High-grade serous ovarian cancer (HGSOC) causes 80% of all ovarian cancer (OC) deaths. In this setting, the role of cancer stem-like cells (CSCs) is still unclear. In particular, the evolution of CSC biomarkers from primary (pOC) to recurrent (rOC) HGSOCs is unknown. Aim of this study was to investigate changes in CD133 and aldehyde dehydrogenase-1 (ALDH1) CSC biomarker expression in pOC and rOC HGSOCs.

METHODS

Two-hundred and twenty-four pOC and rOC intrapatient paired tissue samples derived from 112 HGSOC patients were evaluated for CD133 and ALDH1 expression using immunohistochemistry (IHC); pOCs and rOCs were compared for CD133 and/or ALDH1 levels. Expression profiles were also correlated with patients' clinicopathological and survival data.

RESULTS

Some 49.1% of the patient population (55/112) and 37.5% (42/112) pOCs were CD133+ and ALDH1+ respectively. CD133+ and ALDH1+ samples were detected in 33.9% (38/112) and 36.6% (41/112) rOCs. CD133/ALDH1 coexpression was observed in 23.2% (26/112) and 15.2% (17/112) of pOCs and rOCs respectively. Pairwise analysis showed a significant shift of CD133 staining from higher (pOCs) to lower expression levels (rOCs) (p < 0.0001). Furthermore, all CD133 + pOC patients were International Federation of Gynaecology and Obstetrics (FIGO)-stage III/IV (p < 0.0001) and had significantly worse progression-free interval (PFI) (p = 0.04) and overall survival (OS) (p = 0.02). On multivariate analysis, CD133/ALDH1 coexpression in pOCs was identified as independent prognostic factor for PFI (HR: 1.64; 95% CI: 1.03-2.60; p = 0.036) and OS (HR: 1.71; 95% CI: 1.01-2.88; p = 0.045). Analysis on 52 pts patients with known somatic BRCA status revealed that BRCA mutations did not influence CSC biomarker expression.

CONCLUSIONS

The study showed that CD133/ALDH1 expression impacts HGSOC patients' survival and first suggests that CSCs might undergo phenotypic change during the disease course similarly to non stem-like cancer cells, providing also a first evidence that there is no correlation between CSCs and BRCA status.

Garcinol from Garcinia indica Downregulates Cancer Stem-like Cell Biomarker ALDH1A1 in Nonsmall Cell Lung Cancer A549 Cells through DDIT3 Activation

Nonsmall cell lung cancer (NSCLC) is the predominant type of lung cancer. Patients with NSCLC show high mortality rates because of failure to clean up cancer stem cells (CSCs). The anticancer activity of phytochemical garcinol has been identified in various cancer cell models. However, the effect of garcinol on NSCLC cell lines is still lacking. Of the NSCLC cell lines we tested, A549 cells were the most sensitive to garcinol. Interestingly, Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1) was preferentially expressed in A549 cells and downregulated by the addition of garcinol. We also found that garcinol enriched DNA damage-inducible transcript 3 (DDIT3) and then altered DDIT3-CCAAT-enhancer-binding proteins beta (C/EBPβ) interaction resulting in a decreased binding of C/EBPβ to the endogenous ALDH1A1 promoter. Furthermore, garcinol's inhibition of ALDH1A1 was identified in a xenograft mice model. Garcinol repressed ALDH1A1 transcription in A549 cells through alterations in the interaction between DDIT3 and C/EBPβ. Garcinol could be a potential dietary phytochemical candidate for NSCLCs patients whose tumors harbored high ALDH1A1 expression.

Clinicopathological, prognostic and predictive value of CD166 expression in colorectal cancer: a meta-analysis

CD166 has been identified as an important cancer stem cell (CSC) marker in colorectal cancer (CRC). The purpose of our study was to investigate the relationship between CD166 expression and clinical features and to examine the role of CD166 expression on the survival of patients with CRC. A total of 15 studies with 3,332 cases were identified in this meta-analysis. The pooled OR indicated that CD166 expression was significantly higher in CRC than in colonic adenomas or normal colonic mucosa (OR = 3.48, P = 0.002 and OR = 55.13, P = 0.017, respectively). CD166 expression was found to be negatively correlated with vascular invasion (OR = 0.75, P = 0.017), but it was not associated with gender, tumor location, lymph node status, distant metastasis, clinical stage, T classification or tumor differentiation. Meanwhile, CD166 expression was not associated with the prognosis of overall survival (OS) (HR = 1.20, 95% CI = 0.45-3.22, P = 0.72) in multivariate regression analysis. One study reported that CD166 expression may be a predictor of survival in stage II CRC patients using multivariate logistic regression analysis (OS: OR = 9.97, P = 0.035; disease-specific survival: OR = 29.02, P = 0.011). Our findings suggest that CD166 expression may be correlated with CRC carcinogenesis and a decreased risk of vascular invasion, and it may become a predictive biomarker of survival for stage II CRC patients, but additional studies with large sample sizes are essential to validate the prognostic and predictive values of CD166 expression.

Clinical value of octamer-binding transcription factor 4 as a prognostic marker in patients with digestive system cancers: A systematic review and meta-analysis

BACKGROUND AND AIM

The role of octamer-binding transcription factor 4 (Oct4) has been implicated in the clinical prognosis of various kinds of digestive system cancers, but the results remain controversial. The purpose of this meta-analysis is to assess the potential role of Oct4 as a prognostic marker in digestive system tumors.

METHODS

Relevant articles were retrieved from Pubmed, Web of Science, and Cochrane Library up to July 2016. The software Stata 12.0 was used to analyze the outcomes, including overall survival (OS), disease-free survival, recurrence-free survival, and clinicopathological characteristics.

RESULTS

A total of 13 eligible studies with 1538 patients were included. Elevated Oct4 expression was significantly associated with poor OS (pooled hazard ratio [HR] = 2.183, 95% confidence interval [CI]: 1.824-2.612), disease-free survival (pooled HR = 1.973, 95% CI: 1.538-2.532), and recurrence-free survival (pooled HR = 2.209, 95% CI: 1.461-3.338) of digestive system malignancies. Subgroup analyses showed that cancer type, sample size, study quality, and laboratory detection method did not alter the significant prognostic value of Oct4. Additionally, Oct4 expression was found to be an independent predictive factor for OS (HR = 2.068, 95% CI: 1.633-2.619). No significant association was found between Oct4 and clinicopathological features of digestive system malignancies.

CONCLUSION

This study provided evidence of Oct4 and/or its closely related homolog protein as a predictive factor for patients with digestive system cancers. More large-scale clinical studies on the prognostic value of Oct4 are warranted.

PDGF-D promotes cell growth, aggressiveness, angiogenesis and EMT transformation of colorectal cancer by activation of Notch1/Twist1 pathway

Platelet-derived growth factor-D (PDGF-D) plays a crucial role in the progression of several cancers. However, its role in colorectal cancer (CRC) remains unclear. Our study showed that PDGF-D was highly expressed in CRC tissues and was positively associated with the clinicopathological features. Down-regulation of PDGF-D inhibited the tumor growth, migration and angiogenesis of SW480 cells in vitro and in vivo. Whereas up-regulation of PDGF-D promoted the malignant behaviors of HCT116 cells. Moreover, PDGF-D up-regulated the expression of Notch1 and Twist1 in CRC cells. In addition, PDGF-D expression promoted Epithelial to mesenchymal transition (EMT), which was accompanied with decreased E-cadherin and increased Vimentin expression. Consistently, PDGF-D, Notch1, and Twist1 are obviously up-regulated in transforming growth factor-beta 1 (TGF-β1) treated HCT116 cells. Since Notch1 and Twist1 play an important role in EMT and tumor progression, we examined whether there is a correlation between Notch1 and Twist1 in EMT status. Our results showed that up-regulation of Notch1 was able to rescue the effects of PDGF-D down-regulation on Twist1 expression in SW480 cells, whereas down-regulation of Notch1 reduced Twist1 expression in HCT116 cells. Furthermore, we found that Twist1 promoted EMT and aggressiveness of CRC cells. These results suggest that PDGF-D promotes tumor growth and aggressiveness of CRC, moreover, down-regulation of PDGF-D inactivates Notch1/Twist1 axis, which could reverse EMT and prevent CRC progression.

Evaluation of the Role of ALDH1 as Cancer Stem Cell Marker in Colorectal Carcinoma: An Immunohistochemical Study

INTRODUCTION

Colorectal Carcinoma (CRC) is the third most commonly diagnosed cancer in males. Stem Cells (SC) may be involved in tumour growth, including colon cancer. Aldehyde Dehydrogenase 1 (ALDH1) is a detoxifying enzyme that might modulate SC proliferation.

AIMS

To evaluate the immunohistochemical expression of ALDH1 as stem cell marker in the pathogenesis of colorectal carcinoma.

MATERIALS AND METHODS

This retrospective study included 71 colorectal specimens (49 colorectal carcinoma, 13 adenoma and 9 normal cases) that were collected from Pathology Department, Faculty of Medicine, Menoufia University during the period from 2011 to 2015. All cases were stained by ALDH 1 antibody. Survival data were available for 31cases.

RESULTS

There was a statistical significant association between epithelial positivity of ALDH1 and younger age (p=0.003), right sided tumour (p=0.038), presence of lymph node invasion (p= 0.04), ulcerating gross picture (p=0.01) and presence of vascular invasion (p=0.05). Moreover, there was statistical significant association between stromal positivity of ALDH1 and smaller tumour size (p=0.03) and inverse association between stromal expression of ALDH1 and grade of tumour (p=0.000) and perineural invasion (p= 0.05). Furthermore, there was an inverse significant relation between CD44 and ALDH1 expression (p=0.001). Univariate recurrence free survival analysis revealed the bad prognostic impact of high grade (p=0.03) and female sex (p=0.02) on patient outcome.

CONCLUSION

Epithelial expression of ALDH1 might be associated with poor prognosis while its stromal expression might be associated with good prognosis.

Correlation of DAPK1 methylation and the risk of gastrointestinal cancer: A systematic review and meta-analysis

OBJECTIVE

One of the critical mechanisms of gastrointestinal cancer pathogenesis is the silencing of death associated protein kinase 1 (DAPK1), which could be caused by aberrant methylation of the promoter. However, the relationship between DAPK1 methylation and the risk of gastrointestinal cancer is still controversial. Hence, we conducted this study to determine the potential correlation.

METHODS

Eligible publications were searched in the Pubmed, Embase, and Cochrane Library through November 2016 according to the inclusion criteria and exclusion criteria. Revman 5.3 and Stata 12.0 software were used to analyze the relevant data regarding the association between the frequency of DAPK1 methylation and gastrointestinal cancer.

RESULTS

A total of 22 studies with 2406 patients were included in this meta analysis. Methylation of DAPK1 was positively related with the risk of gastrointestinal cancer (odds ratio [OR] = 5.35, 95% confidence interval [CI]: 2.76-10.38, P<0.00001, random effects model). The source of heterogeneity was analyzed by sensitivity analysis and subgroup analysis. After omitting one heterogeneous study, the I2 decreased and the OR increased in pooled analysis. Also, the heterogeneity decreased most significantly in the subgroup of studies that had a sample size of less than 60 cases. Then, the correlations between DAPK1 methylation and clinicopathological features of gastrointestinal cancer were assessed. DAPK1 methylation was positively correlated with the lymph node (N) stage (positive vs. negative, OR = 1.45, 95%CI: 1.01-2.06, P = 0.04, fixed effects model) and poor differentiation (OR = 1.55, 95%CI: 1.02-2.35, P = 0.04, fixed effects model) in gastric cancer, and the association was significant among Asian patients. However, among cases of gastrointestinal cancer, the association between DAPK1 methylation and tumor (T) stage, N stage, distant metastasis (M) stage, and cancer differentiation were not statistically significant.

CONCLUSIONS

DAPK1 methylation is a potential biomarker for the early diagnosis of gastrointestinal cancer. Further analysis of the clinicopathological features indicated that aberrant methylation of DAPK1 is positively associated with the tumorigenesis of gastrointestinal cancer, and metastasis of gastric cancer.

The biological complexity of colorectal cancer: insights into biomarkers for early detection and personalized care

Colorectal cancer has been ranked the third and second most prevalent of all cancers in men and women, respectively, and it represents the fourth most common cause of cancer deaths. In 2012, there were 1.4 million estimated cases of colorectal cancer worldwide, and 700,000 estimated deaths, which implies significant impact on public health, especially in economically-developed countries. In recent years, there has been an increase in the number of tumors, although this has been accompanied by decreased mortality, due to more appropriate and available information, earlier diagnosis, and improvements in treatment. Colorectal cancers are characterized by great genotypic and phenotypic heterogeneity, including tumor microenvironment and interactions between healthy and cancer cells. All of these traits confer a unique peculiarity to each tumor, which can thus be considered as an individual disease. Well conducted molecular and clinical characterization of each colorectal cancer is essential with a view to the implementation of precision oncology, and thus personalized care. This last aims at standardization of therapeutic plans chosen according to the genetic background of each specific neoplasm, to increase overall survival and reduce treatment side effects. Thus, prognostic and predictive molecular biomarkers assume a critical role in the characterization of colorectal cancer and in the determination of the most appropriate therapy.

The prognostic roles of ALDH1 isoenzymes in gastric cancer

Increased aldehyde dehydrogenase 1 (ALDH1) activity has been determined to be present in the stem cells of several kinds of cancers including gastric cancer (GC). Nevertheless, which ones of ALDH1's isoenzymes are leading to ALDH1 activity remains elusive. In this study, we examined the prognostic value and hazard ratio (HR) of individual ALDH1 isoenzymes in patients with GC using "The Kaplan-Meier plotter" database. mRNA high expression level of ALDH1A1 was not found to be significantly correlated with the overall survival (OS) of all patients with GC followed for 20 years, HR =0.86 (95% confidence interval [CI]: 0.7-1.05), P=0.13. mRNA high expression level of ALDH1A2 was also not significantly correlated with OS for all patients with GC, HR =1.13 (95% CI: 0.91-1.41), P=0.25. mRNA high expression level of ALDH1A3 was found to be significantly correlated with worsened OS in either intestinal-type patients, HR =2.24 (95% CI: 1.44-3.49), P=0.00026, or diffuse-type patients, HR =1.91 (95% CI: 1.02-3.59), P=0.04. Interestingly, mRNA high expression level of ALDH1B1 was found to be significantly correlated with better OS for all patients with GC, HR =0.66 (95% CI: 0.53-0.81), P=7.8e-05, and mRNA high expression level of ALDH1L1 was found to be significantly correlated with worsened OS for all patients with GC, HR =1.23 (95% CI: 1-1.51), P=0.048. Furthermore, our results also indicate that ALDH1A3 and ALDH1L1 are potential major contributors to the ALDH1 activity in GC, since mRNA high expression levels of ALDH1A3 and ALDH1L1 were found to be significantly correlated with worsened OS for all patients with GC. Based on our study, ALDH1A3 and ALDH1L1 are potential prognostic markers and therapeutic targets for patients with GC.