Understanding the colon cancer stem cells and perspectives on treatment

Pen2/ErbB4 signaling regulates stemness of pancreatic ductal carcinoma

Cancer stem cells (CSCs) are critical for progression, invasion, metastasis, and chemotherapy resistance of pancreatic ductal adenocarcinoma (PDAC). Presenilin enhancer 2 (Pen2), a vital component of the gamma-secretase complex, is overexpressed in various cancers and plays a significant role in carcinogenesis. Here, we investigated the association between Pen2 expression and the stem-like properties of PDAC cells. We analyzed Pen2 and its downstream target, Erb-B2 Receptor Tyrosine Kinase 4 (ErbB4), using public databases. The expression of Pen2 in CSC populations, marked by CD133+, CD44+, or epithelial cell adhesion molecule (EpCAM)+, was evaluated. Pen2-positive cells were sorted from Pen2-negative ones in PDAC cells transduced with a vector designed to express green fluorescent protein (GFP) under the Pen2 promoter. Stemness was examined in vitro and in vivo in Pen2-positive versus Pen2-negative cells. Our results showed that Pen2 was significantly upregulated, while ErbB4 was significantly downregulated in PDAC tissues compared to adjacent non-tumorous tissues, with an inverse relationship between Pen2 and Erbb4 levels. PDACs with high Pen2 expression are associated with considerably poorer patient survival. The CSC populations identified by CD133+, CD44+, and EpCAM+ markers displayed significantly higher Pen2 and lower EpCAM levels. Compared to Pen2-negative PDAC cells, Pen2-positive cells formed more tumor spheres, were more invasive and migratory, and showed significantly increased resistance to chemotherapy-induced apoptosis. Altering Pen2 levels reversed these oncogenic effects. In vivo, Pen2-positive cells formed larger tumors in immunodeficient mice. Overall, our findings suggest that Pen2 is highly expressed in CSCs within PDAC cells, being a novel therapeutic target.

Colorectal cancer: a comprehensive review of carcinogenesis, diagnosis, and novel strategies for classified treatments

Colorectal cancer is the third most common and the second deadliest cancer worldwide. To date, colorectal cancer becomes one of the most important challenges of the health system in many countries. Since the clinical symptoms of this cancer appear in the final stages of the disease and there is a significant golden time between the formation of polyps and the onset of cancer, early diagnosis can play a significant role in reducing mortality. Today, in addition to colonoscopy, minimally invasive methods such as liquid biopsy have received much attention. The treatment of this complex disease has been mostly based on traditional treatments including surgery, radiotherapy, and chemotherapy; the high mortality rate indicates a lack of success for current treatment methods. Moreover, disease recurrence is another problem of traditional treatments. Recently, new approaches such as targeted therapy, immunotherapy, and nanomedicine have opened new doors for cancer treatment, some of which have already entered the market, and many methods have shown promising results in clinical trials. The success of immunotherapy in the treatment of refractory disease, the introduction of these methods into neoadjuvant therapy, and the successful results in tumor shrinkage without surgery have made immunotherapy a tough competitor for conventional treatments. It seems that the combination of those methods with such targeted therapies will go through promising changes in the future of colorectal cancer treatment.

Reciprocal relationship between cancer stem cells and myeloid-derived suppressor cells: implications for tumor progression and therapeutic strategies

Recently, there has been an increased focus on cancer stem cells (CSCs) due to their resilience, making them difficult to eradicate. This resilience often leads to tumor recurrence and metastasis. CSCs adeptly manipulate their surroundings to create an environment conducive to their survival. In this environment, myeloid-derived suppressor cells (MDSCs) play a crucial role in promoting epithelial-mesenchymal transition and bolstering CSCs' stemness. In response, CSCs attract MDSCs, enhancing their infiltration, expansion and immunosuppressive capabilities. This interaction between CSCs and MDSCs increases the difficulty of antitumor therapy. In this paper, we discuss the interplay between CSCs and MDSCs based on current research and highlight recent therapeutic strategies targeting either CSCs or MDSCs that show promise in achieving effective antitumor outcomes.

The Antioxidant and Antitumor Efficiency of Litophyton sp. Extract in DMH-Induced Colon Cancer in Male Rats

One of the most common tumors to cause death worldwide is colon cancer. This study aims to investigate the antitumor potency of Litophyton sp. methanolic extract (LME) against DMH-induced colon cancer in adult male rats. Group (1) normal rats served as the control, group (2) normal rats were ip-injected with LME at a dose of 100 μg/kg/day, group (3) DMH-induced colon cancer animals, and group (4) colon cancer-modeled animals were treated with LME (100 μg/kg/day) for six weeks. The results revealed that injection of LME markedly regenerated the colon cancer pathophysiological disorders; this was monitored from the significant reduction in the values of serum biomarkers (CEA, CA19.9, AFP), cytokines (TNF-α and IL1β), and biochemical measurements (ALAT, ASAT, urea, creatinine, cholesterol, and triglycerides) matched significant increase of apoptotic biomarkers (CD4+); similarly, colon DNA fragmentation, MDA, and NO levels were down-regulated. In contrast, a remarkable upregulation in colon SOD, GPx, GSH, and CAT levels was noted. Moreover, the colon histopathological architecture showed obvious regenerations. Chromatography of LME resulted in the purification of two polyhydroxylated steroids (1 and 2) with potential cytotoxic activities. LME performed therapeutic potential colon tumorigenesis; therefore, LME may have a promising chemo-preventive feature against colon cancer, probably via enhancement of the apoptosis pathway, improvement of the immune response, reduction of inflammation, or/and restoration of the impaired oxidative stress.

Preventive cancer stem cell-based vaccination modulates tumor development in syngeneic colon adenocarcinoma murine model

BACKGROUND

Cancer stem cells (CSCs), a rare sub-fraction of tumor cells, with the capability of self-renewal and strong oncogenicity are tightly responsible for chemo and radio resistance and tumor metastasis in colorectal cancer. Hence, CSCs targeting would improve the efficacy of therapeutic strategies and clinical outcomes.

METHODS

Here, using three-dimensional CSC spheroids and syngeneic mice model, we evaluated the cancer preventive impact of CSCs-based vaccination. CSCs enrichment was performed via colonosphere formation from CT-26 cell line and CT-26-derived tumor biopsy and characterized by confirming high expression of key stemness genes (OCT4, SOX2, and NANOG) and CSC-related surface biomarkers (CD166, DCLK1, and CD133) via real-time PCR and flow cytometry, respectively. Then, the stemness phenotype and self-renewal in CSC-enriched spheroids were further confirmed by showing serial sphere formation capacity, clonogenicity potential, and enhanced in vivo tumorigenic capacity compared to their parental counterparts. CSCs lysates were used as vaccines in prophylactic settings compared to the parental cell lysate and PBS groups.

RESULT

Immunization of syngeneic mice with CSCs lysates was effective in the prevention of tumor establishment and significantly decreased tumor growth rate accompanied by an improvement in survival rate in tumor-bearing mice compared to groups subjected to parental cells lysate and PBS. These results, for the first time, showed that mice immunized with cell lysate from tumor biopsy-derived spheroids are resistant to tumor induction. Immunofluorescence staining indicated that only the serum antibodies from CSC-vaccinated mice reacted with colonospheres.

CONCLUSIONS

These findings represent CSCs lysate-based vaccination as a potential approach to hampering immunotherapy failure of colorectal cancer which along with other traditional therapies may effectively apply to prevent the establishment of aggressive tumors harboring stemness features.

Comparative Study between Curcumin and Nanocurcumin Loaded PLGA on Colon Carcinogenesis Induced Mice

Colorectal cancer is the third most common cancer. Because curcumin (CUR) has anti-inflammatory and anticancer properties, research has been undertaken to indicate that nanocurcumin compounds can be used to treat a variety of cancers. CUR in nanoform has been found to have a stronger effect than conventional CUR. The purpose of this study was to show that CUR-loaded poly lactic-co-glycolic acid nanoparticles (PLGA) (CUR-loaded PLGA) have anti-inflammatory and anticancer effects on colon carcinogenesis in male dimethyl hydrazine (DMH) mice as a comparative study between the nanoform of curcumin and normal curcumin, focusing on the anticancer effect of nanocurcumin. Mice were separated into six groups: No treatment was given to Group I (negative Group-I). Group II was treated with CUR. Group III was treated with CUR-loaded PLGA. Group IV was treated with DMH. Group V received DMH and curcumin. Group VI received DMH and CUR-loaded PLGA. At the conclusion of the trial, the animals were slain (6 weeks). Inflammatory indicators and vascular endothelial growth factor (VEGF) levels all changed significantly in this study, as the following inflammatory markers as TNF showed percent of change compared to the DMH group. Recovery percentage for Groups V and VI, respectively, were 9.18 and 55.31%. In addition, IL1 was 7.45 and 50.37% for Groups V and VI, respectively. The results of IL6 were 4.86 and 25.79% for Groups V and VI, respectively. The vascular endothelial growth factor (VEGF) recovery percent was 16.98 and 45.12% for Groups V and VI, respectively. Following the effect of DMH on colon mucosa shape, the researchers looked at the effect of CUR-loaded PLGA on colon histology. It was shown that CUR-loaded PLGA affects the cell cycle and PCNA expression. We conclude that nanocurcumin is an important anti-inflammatory and cancer-fighting agent.

Preoperative Absolute Lymphocyte Count to Carcinoembryonic Antigen Ratio Is a Superior Predictor of Survival in Stage I to III Colorectal Cancer

Background:

Preoperative absolute lymphocyte count (ALC) and carcinoembryonic antigen (CEA) are useful prognostic indicators in colorectal cancer (CRC); however, the role of the ALC-to-CEA ratio (LCR) has been less addressed.

Methods:

A total of 189 stage I to III CRC patients who underwent radical resection were enrolled retrospectively. The significance of the LCR in predicting disease-free survival (DFS) and overall survival (OS) was calculated and compared with other markers based on ALC. The DFS and OS differences among the low- and high-LCR subgroups and risk factors for the outcome were estimated by Kaplan–Meier analysis and the Cox proportional hazards model, respectively.

Results:

Taking 0.28 as the cutoff point, the LCR has a sensitivity and a specificity of 75.60% and 77.00%, respectively, in predicting OS. The prognostic efficacy of LCR was significantly superior to that of other markers based on ALC for predicting DFS and OS. A total of 34.92% (66/189) of patients displayed a low LCR (<0.28), and these patients were more likely to present poor cell differentiation (P = .03), tumor deposits (P < .01) and advanced T (P < .01) and liver metastasis (P = .02). Patients with a low LCR had significantly worse DFS (Log Rank = 34.98, P < .01) and OS (Log Rank = 43.17, P < .01) than those with a high LCR. The LCR was an independent prognostic factor for both DFS (hazard ratio (HR) = 0.35, 95% confidence interval (CI): 0.20-0.62, P < .01) and OS (HR = 0.18, 95% CI: 0.08-0.37, P < .01).

Conclusions:

The LCR is a superior predictor of survival in stage I to III CRC, and patients with a low LCR have an inferior outcome; however, additional studies are required to validate its prognostic role.

Chemosensitivity analysis and study of gene resistance on tumors and cancer stem cell isolates from patients with colorectal cancer

Colorectal cancer (CRC) is one of the main causes of mortality. Recent studies suggest that cancer stem cells (CSCs) can survive after chemotherapy and promote tumor invasiveness and aggression. According to a higher hierarchy complexity of CSC, different protocols for isolation, expansion, and characterization have been used; however, there are no available resistance biomarkers that allow predicting the clinical response of treatment 5‑fluorouracil (5FU) and oxaliplatin. Therefore, the primary aim of the present study was to analyze the expression of gene resistance on tumors and CSC‑derived isolates from patients CRC. In the present study, adenocarcinomas of the colon and rectum (CRAC) were classified based on an in vitro adenosine triphosphate‑based chemotherapy response assay, as sensitive and resistant and the percentage of CD24 and CD44 markers are evaluated by immunohistochemistry. To isolate resistant colon‑CSC, adenocarcinoma tissues resistant to 5FU and oxaliplatin were evaluated. Finally, all samples were sequenced using a custom assay with chemoresistance‑associated genes to find a candidate gene on resistance colon‑CSC. Results showed that 59% of the CRC tissue analyzed was resistant and had a higher percentage of CD44 and CD24 markers. An association was found in the expression of some genes between the tumor‑resistant tissue and CSC. Overall, isolates of the CSC population CD44+ resistant to 5FU and oxaliplatin demonstrated different expression profiles; however, the present study was able to identify overexpression of the KRT‑18 gene, in most of the isolates. In conclusion, the results of the present study showed overexpression of KRT‑18 in CD44+ cells is associated with chemoresistance to 5FU and oxaliplatin in CRAC.

Personalized medicine: Stem cells in colorectal cancer treatment

Treatment failure in primary as well as metastatic cancer patients, caused by chemo and radioresistance, has reinforced the research for the applicability of personalized medicine. The use of stem cells (SCs) and cancer stem cells (CSCs) in such a treatment approach will be reviewed in this study. Colorectal cancer (CRC) SCs prove to be a promising asset for CRC treatment optimization both by serving as biomarkers for the current therapy modalities, by means of treatment personalization and patient/tumor stratification, as well as in the development of targeted therapies, selective for the stem cell population. Similar conclusions are drawn, regarding mesenchymal stromal cells (MSCs) and their effect in CRC therapy; while resident stromal cells (RSCs) of tumor microenvironment (TME) seem to promote the tumorigenic and metastatic processes in addition to conferring to the chemo- and radioresistance, under certain conditions they are able to improve the treatment outcome of CRC chemotherapy, e.g. by targeted enzyme/prodrug treatment of CRC cells. This review, points out the dynamic potential of CSCs and other SCs types in CRC treatment personalization as well as, in the improvement of current treatment approaches, opting to a higher therapeutic rate, improved prognosis, survival and quality of life for CRC patients.

Leucine-rich repeat-containing G protein-coupled receptor 5 marks different cancer stem cell compartments in human Caco-2 and LoVo colon cancer lines

BACKGROUND

Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers. It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5)-expressing stem cells, these so-called “tumour-initiating” cells, reminiscent in their properties of the normal intestinal stem cells (ISCs), may explain the apparent heterogeneity of colon cancer cell lines. Also, colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5. Furthermore, in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.

AIM

To investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.

METHODS

A portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines (Caco-2 and LoVo). These cells were then characterized according to their proliferation capacity, gene expression signatures of ISC markers, and their tumorigenic properties in vivo and in vitro.

RESULTS

The data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2, but not from the LoVo, cell lines, in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog (+4 crypt) stem cells. This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny. Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein (EYFP) from this cell line exhibit tumorigenic-like properties in vivo and in vitro. In contrast, cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties. Thus, cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells, but not LoVo cells.

CONCLUSION

Our findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines. Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data. We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.

Molecular subtypes of colorectal cancer: An emerging therapeutic opportunity for personalized medicine

Molecular subtypes-based therapies offer new potential framework for desired and precise outcome in clinical settings. Current treatment strategies in colorectal cancer are largely 'one drug fit all' model for patients that display same pathological conditions. However, CRC is a very heterogenous set of malignancy that does not support for above criteria. Each subtype displays different pathological and genetic signatures. Based on these features, therapeutic stratification for individual patients may be designed, which may ultimately lead to improved therapeutic outcomes. In this comprehensive review, we have attempted to briefly outline major CRC pathways. A detailed overview of molecular subtypes and their clinical significance has been discussed. Present and future methods, governing CRC subtyping in the era of personalized therapy with a special emphasis on CMS subtypes of CRC has been reviewed. Together, discovery and validation of new CRC patient stratification methods, screening for novel therapeutic targets, and enhanced diagnosis of CRC may improve the treatment outcome.

Dendritic cells loaded with exosomes derived from cancer stem cell-enriched spheroids as a potential immunotherapeutic option

Cancer stem cells (CSCs) are responsible for therapeutic resistance and recurrence in colorectal cancer. Despite advances in immunotherapy, the inability to specifically eradicate CSCs has led to treatment failure. Hence, identification of appropriate antigen sources is a major challenge in designing dendritic cell (DC)‐based therapeutic strategies against CSCs. Here, in an in vitro model using the HT‐29 colon cancer cell line, we explored the efficacy of DCs loaded with exosomes derived from CSC‐enriched colonospheres (CSC_enr‐EXOs) as an antigen source in activating CSC‐specific T‐cell responses. HT‐29 lysate, HT‐29‐EXOs and CSC_enr lysate were independently assessed as separate antigen sources. Having confirmed CSCs enrichment in spheroids, CSC_enr‐EXOs were purified and characterized, and their impact on DC maturation was investigated. Finally, the impact of the antigen‐pulsed DCs on the proliferation rate and also spheroid destructive capacity of autologous T cells was assessed. CSC_enr‐EXOs similar to other antigen groups had no suppressive/negative impacts on phenotypic maturation of DCs as judged by the expression level of costimulatory molecules. Notably, similar to CSC_enr lysate, CSC_enr‐EXOs significantly increased the IL‐12/IL‐10 ratio in supernatants of mature DCs. CSC_enr‐EXO‐loaded DCs effectively promoted T‐cell proliferation. Importantly, T cells stimulated with CSC_enr‐EXOs disrupted spheroids' structure. Thus, CSC_enr‐EXOs present a novel and promising antigen source that in combination with conventional tumour bulk‐derived antigens should be further explored in pre‐clinical immunotherapeutic settings for the efficacy in hampering recurrence and metastatic spread.

CD133 peptide-conjugated pyropheophorbide-a as a novel photosensitizer for targeted photodynamic therapy in colorectal cancer stem cells

Colorectal cancer (CRC) is the third most common cancer around the world. Recent findings suggest that cancer stem cells (CSCs) play a pivotal role in the resistance to current therapeutic modalities, including surgery and chemotherapy. Photodynamic therapy (PDT) is a promising non-invasive therapeutic strategy for advanced metastatic CRC. Traditional photosensitizers such as pyropheophorbide-a (Pyro) lack tumor selectivity, causing unwanted treatment-related toxicity to the surrounding normal tissue. In order to enhance the targeting properties of Pyro, we synthesize a novel photosensitizer, CD133-Pyro, via the conjugation of Pyro to a peptide domain targeting CD133, which is highly expressed on CRC CSCs and correlated with poor prognosis of CRC patients. We demonstrate that CD133-Pyro possesses the targeted delivery capacity both in CRC CSCs derived from HT29 and SW620 cell lines and in a xenograft mouse model of tumor growth. CD133-Pyro PDT can promote the production of reactive oxygen species (ROS), suppress the stemness properties, and induce autophagic cell death in CRC CSCs. Furthermore, CD133-Pyro PDT has a potent inhibitory effect on CRC CSC-derived xenograft tumors in nude mice. These findings may offer a useful and important strategy for the treatment of CRC through targeting CSCs.

Radiosensitivity of Cancer Stem Cells Has Potential Predictive Value for Individual Responses to Radiotherapy in Locally Advanced Rectal Cancer

Simple Summary

Radiotherapy is often used as a neo-adjuvant treatment in locally advanced rectal cancer. While treatment generally induces an improvement in the outcome, some patients show resistance to treatment for reasons that still have to be elucidated. In this work, we report an in vitro and in vivo model based on patient-derived cancer stem cells. This model is able to predict individual responses to radiotherapy. The results indicate that cells found to be radiation-sensitive in vitro generated radiation-sensitive tumor xenografts upon subcutaneous implantation. Analogously, cancer stem cells (CSCs) that did not respond to in vitro radiation treatment generated radiation-resistant tumor xenografts. Moreover, radioresistant CSCs were generally isolated via biopsies of patients with poor responses to neo-adjuvant radiotherapy. This suggests that a cell-based in vitro test may itself be sufficient to predict outcomes in donor patients.

Abstract

Neo-adjuvant radiotherapy is frequently employed in the therapeutic management of locally advanced rectal cancer (LARC). Radiotherapy can both reduce local recurrence and improve the success of surgical procedures by reducing tumor mass size. However, some patients show a poor response to treatment, which results in primary resistance or relapse after apparent curative surgery. In this work, we report in vitro and in vivo models based on patient-derived cancer stem cells (CSCs); these models are able to predict individual responses to radiotherapy in LARC. CSCs isolated from colorectal cancer biopsies were subjected to in vitro irradiation with the same clinical protocol used for LARC patients. Animal models, generated by CSC xenotransplantation, were also obtained and treated with the same radiotherapy protocol. The results indicate that CSCs isolated from rectal cancer needle biopsies possess an intrinsic grade of sensitivity to treatment, which is also maintained in the animal model. Notably, the specific CSCs’ in vitro and in vivo sensitivity values correspond to patients’ responses to radiotherapy. This evidence suggests that an in vitro radiotherapy response predictivity assay could support clinical decisions for the management of LARC patients, thus avoiding radiation toxicity to resistant patients and reducing the treatment costs.

Nonalcoholic fatty liver disease and colorectal cancer: Correlation and missing links

Nonalcoholic fatty liver disease (NAFLD) is one of the major metabolic diseases that occur in almost one in every four global population, while colorectal cancer (CRC) is one of the leading causes of cancer related deaths in the world. Individuals with pre-existing NAFLD show a higher rate of developing CRC and liver metastasis, suggesting a causal relationship. Interestingly, both of these diseases are strongly associated with obesity, which is also a growing global health concern. In this current review, we will explore scientific findings that demonstrate the relationship between NAFLD, CRC and obesity, as well as the underlying mechanisms. We will also indicate the missing links and knowledge gaps that require more in-depth investigation.

Thymoquinone induces apoptosis and DNA damage in 5-Fluorouracil-resistant colorectal cancer stem/progenitor cells

The high recurrence rates of colorectal cancer have been associated with a small population of cancer stem cells (CSCs) that are resistant to the standard chemotherapeutic drug, 5-fluorouracil (5FU). Thymoquinone (TQ) has shown promising antitumor properties on numerous cancer systems both in vitro and in vivo; however, its effect on colorectal CSCs is poorly established. Here, we investigated TQ's potential to target CSCs in a three-dimensional (3D) sphere-formation assay enriched for a population of colorectal cancer stem/progenitor cells. Our results showed a significant decrease in self-renewal potential of CSC populations enriched from 5FU-sensitive and resistant HCT116 cells at 10-fold lower concentrations when compared to 2D monolayers. TQ decreased the expression levels of colorectal stem cell markers CD44 and Epithelial Cell Adhesion Molecule EpCAM and proliferation marker Ki67 in colonospheres derived from both cell lines and reduced cellular migration and invasion. Further investigation revealed that TQ treatment led to increased TUNEL positivity and a dramatic increase in the amount of the DNA damage marker gamma H2AX particularly in 5FU-resistant colonospheres, suggesting that the diminished sphere forming ability in TQ-treated colonospheres is due to induction of DNA damage and apoptotic cell death. The intraperitoneal injection of TQ in mice inhibited tumor growth of spheres derived from 5FU-sensitive and 5FU-resistant HCT116 cells. Furthermore, TQ induced apoptosis and inhibited NF-κB and MEK signaling in mouse tumors. Altogether, our findings document TQ's effect on colorectal cancer stem-like cells and provide insights into its underlying mechanism of action.

Decreased lncRNA, TINCR, promotes growth of colorectal carcinoma through upregulating microRNA-31

Abnormal expression in terminal differentiation-induced noncoding RNA (TINCR), a long non-coding RNA (lncRNA), has been reported in different human cancers, including colorectal carcinoma (CRC). Moreover, the molecular mechanisms that underlie the effects of TINCR on CRC remain unclear. Here, by a set of bioinformatics studies, we found that microRNA-31 (miR-31), the oncogenic miRNA that robustly upregulates in CRC, was a sponge miRNA for TINCR. TINCR and miR-31 levels were inversely correlated in both CRC tissues and CRC cell lines. Luciferase reporter assay revealed a specific binding site on TINCR for miR-31. Suppression of TINCR promoted CRC cell growth and migration in vitro, while overexpression of TINCR inhibited CRC cell growth and migration in vitro. TINCR depletion increased tumor xenograft growth in vivo, while TINCR overexpression inhibited it. Together, our study suggests that re-expressing TINCR may suppress invasive outgrowth of CRC through miR-31.

The heparan sulfate proteoglycan syndecan-1 regulates colon cancer stem cell function via a focal adhesion kinase-Wnt signaling axis

In colon cancer, downregulation of the transmembrane heparan sulfate proteoglycan syndecan-1 (Sdc-1) is associated with increased invasiveness, metastasis, and dedifferentiation. As Sdc-1 modulates signaling pathways relevant to stem cell function, we tested the hypothesis that it may regulate a tumor-initiating cell phenotype. Sdc-1 small-interfering RNA knockdown in the human colon cancer cell lines Caco2 and HT-29 resulted in an increased side population (SP), enhanced aldehyde dehydrogenase 1 activity, and higher expression of CD133, LGR5, EPCAM, NANOG, SRY (sex-determining region Y)-box 2, KLF2, and TCF4/TCF7L2. Sdc-1 knockdown enhanced sphere formation, cell viability, Matrigel invasiveness, and epithelial-to-mesenchymal transition-related gene expression. Sdc-1-depleted HT-29 xenograft growth was increased compared to controls. Decreased Sdc-1 expression was associated with an increased activation of β1-integrins, focal adhesion kinase (FAK), and wingless-type (Wnt) signaling. Pharmacological FAK and Wnt inhibition blocked the enhanced stem cell phenotype and invasive growth. Sequential flow cytometric SP enrichment substantially enhanced the stem cell phenotype of Sdc-1-depleted cells, which showed increased resistance to doxorubicin chemotherapy and irradiation. In conclusion, Sdc-1 depletion cooperatively enhances activation of integrins and FAK, which then generates signals for increased invasiveness and cancer stem cell properties. Our findings may provide a novel concept to target a stemness-associated signaling axis as a therapeutic strategy to reduce metastatic spread and cancer recurrence. DATABASES: The GEO accession number of the Affymetrix transcriptomic screening is GSE58751.

Peptide-enhanced tumor accumulation of upconversion nanoparticles for sensitive upconversion luminescence/magnetic resonance dual-mode bioimaging of colorectal tumors

Currently, it is still a great challenge to develop tumor targeting nanoparticles with high sensitivity and high resolution for improving the non-invasive detection ability of colorectal cancer (CRC) at an early stage. In this study, NaErF₄:Yb@NaGdF₄:Yb core@shell upconversion nanoparticles (UCNPs) were prepared with high upconversion luminescence (UCL) emission in red light region through adjusting the doping ratios of Er and Yb elements in the core. For biomedical applications, the carboxyl-terminated silica shell was introduced to transfer the as-prepared UCNPs from the organic phase to the aqueous phase, and allowed conjugation with peptide ligands derived from the l-SP5 peptide (i.e., l-SP5-H and l-SP5-C), respectively. Due to the tumor-targeting affinity of the PSP motif in the peptide ligands, the as-prepared peptide functionalized UCNPs (UCNP@SiO₂-l-SP5-H and UCNP@SiO₂-l-SP5-C) can be used as an active tumor targeting contrast agents for UCL/T₁-weighted magnetic resonance (MR) dual-mode imaging. Both the in vitro and in vivo experimental results demonstrated that UCNP@SiO₂-l-SP5-C has relatively high affinity for the HCT116 CRC subtype. Moreover, UCNP@SiO₂-l-SP5-C can visualize ultra-small subcutaneous xenografted HCT116 tumors (c.a. 13 mm³ in volume) by in vivo UCL imaging. STATEMENT OF SIGNIFICANCE: 1. High red emission UCNPs were synthesized for tumor-targeting dual-mode bioimaging. 2. With tumor-binding affinity peptide, UCNP@SiO₂-l-SP5-C shows high HCT116 tumor targeting ability. 3. UCNP@SiO₂-l-SP5-C successfully achieves sensitive detection of ultrasmall HCT116 tumors.

Indium-111-labeled CD166-targeted peptide as a potential nuclear imaging agent for detecting colorectal cancer stem-like cells in a xenograft mouse model

BACKGROUND

Cancer stem cells (CSCs) are involved in drug resistance, metastasis, and relapse of cancers, which can significantly affect tumor therapy. Hence, to develop specifically therapeutic target probe at CSCs for improvement of survival and quality of life of cancer patients is urgently needed. The CD166 protein has been suggested to be involved in colorectal cancer (CRC) tumorigenesis and to be considered a marker for colorectal CSCs (CRCSCs) detection. In this study, therefore, we attend to apply a nuclear imaging agent probe, Glycine₁₈-Cystine-linked CD166-targeted peptides (CD166tp-G₁₈C), to detect the changes of CD166 level in a CRC xenograft mouse model.

RESULTS

We isolated the CD166-positive cells from the HCT15 CRC cell line (CD166⁺HCT15) and evaluated their morphology and ability of clone formation, migration, protein expression, and drug resistance. The CD166-positive HCT15 cells display the CSCs characteristics. We discovered and designed a CD166-targeted peptide (CD166tp-G₁₈C) as a targeted probe of CRC stem-like cell for cell binding assay. The CD166tp-G₁₈C confirmed the CD166 protein targeting ability in CD166⁺HCT15 cells. The diethylenetriaminopentaacetic acid (DTPA)-conjugated CD166tp-G₁₈C further was labeled with indium-111 (¹¹¹In-DTPA-CD166tp-G₁₈C) as nuclear imaging agent for imaging and bio-distribution analysis in vivo. Finally, we observed that the ¹¹¹In-DTPA-CD166tp-G₁₈C was significantly enhanced in tumor tissues of CD166⁺HCT15 xenograft mice as compared to the non-CD166tp-G₁₈C control.

CONCLUSIONS

Our results indicated that the indium-111-labeled CD166tp-G₁₈C may be served as a powerful tool for colorectal CSCs nuclear imaging in the CRC patients.

Effects of pericytes and colon cancer stem cells in the tumor microenvironment

Colorectal cancer (CRC) is one type of tumor with the highest frequency and mortality worldwide. Although current treatments increase patient survival, it is important to detect CRC in early stages; however, most CRC, despite responding favorably to treatment, develop resistance and present recurrence, a situation that will inevitably lead to death. In recent years, it has been shown that the main reason for drug resistance is the presence of colon cancer stem cells (CSC). Pericytes are also capable of tumor homing and are important cellular components of the tumor microenvironment (TME), contributing to the formation of vessels and promoting metastasis; however, they have not been considered very important as a therapeutic target in cancer. In this review, we highlight the contribution of pericytes and cancer stem cells to some classical hallmarks of cancer, namely, tumor angiogenesis, growth, metastasis, and evasion of immune destruction, and discuss therapies targeting pericytes and cancer stem cells in CRC.

Long noncoding RNA UCA1 enhances sensitivity to oncolytic vaccinia virus by sponging miR-18a/miR-182 and modulating the Cdc42/filopodia axis in colorectal cancer

The promising anti-tumor effects of oncolytic vaccinia virus (OVV) have been demonstrated. Further, we previously showed that long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) enhances OVV cell-to-cell spread via the activation of Cdc42 in ovarian cancer. However, its role in other cancer types and the molecular mechanism underlying its effects remain to be explored. In this study, we first demonstrated that UCA1 upregulates OVV cell-to-cell spread but not its binding, entry, and replication in colorectal cancer cells. Functional analysis indicated that Cdc42 activation and filopodia formation play an important role in this process. Moreover, expression analysis of various miRNAs suggested that UCA1 inhibits both miR-18a and miR-182, thereby promoting Cdc42 activation, which in turn, regulates OVV cell-to-cell spread. Furthermore, UCA1 was found to modulate tumor malignancy, drug resistance, and sensitivity to OVV via different miRNAs in colorectal cancer. These findings indicate that a three-marker panel, which includes UCA1 expression, Cdc42 activation, and filopodia formation, could potentially be used to predict the therapeutic effect of OVV in colorectal cancer.

Modulation of CD44, EGFR and RAC Pathway Genes (WAVE Complex) in Epithelial Cancers

Cancer hallmarks help in understanding the diversity of various neoplasms. Epithelial cancers play an immense role in the tumor biology through Epithelial-Mesenchymal Transition (EMT) process. Receptor tyrosine kinase, as well as phosphatidyl ionositol-3 kinase pathways, play an important role in the regulation of cell proliferation, survival, and differentiation during EMT. Till date, numerous studies have shown modulation in the expression profile of potential targets like CD44, EGFR, and Rac in epithelial cancers. CD44 interacts with EGFR and recruits other molecules which further activate the Rac pathway intermediates. This review mainly focused on modulation of genes like CD44, EGFR, and Rac pathway intermediates which play a crucial role in the tumor progression, metastasis, proliferation, and invasion characteristics in epithelial cancers with EMT properties. Hence, targeting Rac pathway might be a more strategically relevant approach in treating epithelial cancers.

Correlation study of GAPDH, Bcl-2, and Bax protein immunoexpression in patients with colorectal adenocarcinoma

Introduction

Colorectal cancer (CRC) is the third and second most commonly diagnosed cancer worldwide in males and females, respectively. Despite prominent progress in diagnosis and treatment, the recurrence rates are still high. A tumour hypoxic environment leads to an increase in glycolytic metabolism. The crucial intermediate component of glycolysis, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), could play a significant role in cancer progression. An increased level of GAPDH has been described in oncogene-induced transformation and anti-apoptotic function. In other studies, GAPDH has been involved in apoptosis induction.

Aim

We examined colorectal adenocarcinoma samples to assess the immunoexpression of GAPDH protein. We also evaluated the correlation between the expression of GAPDH protein and apoptotic parameters including expression of Bcl2 and Bax.

Material and methods

Paraffin sections were incubated for 60 min with primary antibody against GAPDH, Bcl-2, and Bax.

Results

Results of our study have shown that GAPDH expression in colorectal cancer is upregulated. We revealed significant positive correlation between expression of this protein and grade and size of tumour, and regional lymph node involvement. In the case of apoptosis-associated proteins, e.g. Bcl-2 and Bax, we found negative correlations between expression of these proteins and grade and size of tumour, lymphovascular invasion, and regional lymph node involvement. Finally, we demonstrated that GAPDH up-regulation is connected with down-regulation in Bcl-2 and Bax.

Conclusions

Up-regulation of GAPDH protein and down-regulation of Bcl-2 and Bax may result in increased of cancer.

GLI1 promotes cancer stemness through intracellular signaling pathway PI3K/Akt/NFκB in colorectal adenocarcinoma

The role of Hedgehog (HH)/ glioma-associated oncogene homolog 1 (GLI1) pathway has been implicated in a variety of cancer entities, and the targeted pathway inhibition mediated by GLI1 is of therapeutic relevance. However, its oncogenicity and cross-talks with other cancer pathways including PI3K/Akt/NFκB, which modulates the HH/GLI1 signal strength, have rarely been explored in colorectal adenocarcinoma. We assessed the expression of GLI1 and its relationship with other cancer stemness genes, cell cycle markers, epithelial-mesenchymal transition (EMT), PI3K/Akt/NFκB signaling pathway genes, and HIF1α in 100 paraffin-embedded colorectal adenocarcinoma tissue samples using immunohistochemistry. We further addressed the effect of GLI1 on EMT, cell cycle, and its putative interaction with the PI3K/Akt/NFκB cascade in colorectal adenocarcinoma cell lines. The expression of GLI1 in colorectal adenocarcinoma tissues was found to correlate with the clinical stages, and distant metastasis. Moreover, GLI1 was found to be an independent predictor of poor overall survival and disease-free survival in colorectal adenocarcinoma. GLI1-expressing cancer cells also expressed their representative cancer stem-like cell (CSC) markers (SOX9 and CD133), as well as HIF1α. GLI1 expression was also strongly linked to EMT-related and PI3K/Akt/NFκB signaling genes. Downregulation of GLI1 by inhibitor treatment in colorectal adenocarcinoma cell lines resulted in reduced expression of CSC markers, cell clonogenicity, S-phase subpopulations, as well as the migration and invasion ability. Importantly, Akt inhibitor Perifosine significantly inhibited the expression of pAkt and GLI1 in colorectal adenocarcinoma cells. Combination of GLI1 inhibitor GANT61 and NFκB p65 inhibitor QZN exhibited much higher inhibition compared to using any of them individually on colorectal adenocarcinoma cells. We suggested that GLI1 may be a novel stem cell marker, and cancer stemness was activated via PI3K/Akt/NFκB pathway. In addition, co-targeting GLI1 and PI3K/Akt/NFκB signaling simultaneously might provide an alternative therapeutic strategy for colorectal adenocarcinoma patients.

Exosomes Regulate the Transformation of Cancer Cells in Cancer Stem Cell Homeostasis

In different biological model systems, exosomes are considered mediators of cell-cell communication between different cell populations. Exosomes, as extracellular vesicles, participate in physiological and pathological processes by transmitting signaling molecules such as proteins, nucleic acids, and lipids. The tumor's microenvironment consists of many types of cells, including cancer stem cells and mesenchymal cells. It is well known that these cells communicate with each other and thereby regulate the progression of the tumor. Recent studies have provided evidence that exosomes mediate the interactions between different types of cells in the tumor microenvironment, providing further insight into how these cells interact through exosome signaling. Cancer stem cells are a small kind of heterogeneous cells that existed in tumor tissues or cancer cell lines. These cells possess a stemness phenotype with a self-renewal ability and multipotential differentiation which was considered the reason for the failure of conventional cancer therapies and tumor recurrence. However, a highly dynamic equilibrium was found between cancer stem cells and cancer cells, and this indicates that cancer stem cells are no more special target and blocking the transformation of cancer stem cells and cancer cells seem to be a more significant therapy strategy. Whether exosomes, as an information transforming carrier between cells, regulated cancer cell transformation in cancer stem cell dynamic equilibrium and targeting exosome signaling attenuated the formation of cancer stem cells and finally cure cancers is worthy of further study.

ALDH1A inhibition sensitizes colon cancer cells to chemotherapy

Background

Recent evidence in cancer research, developed the notion that malignant tumors consist of different subpopulations of cells, one of them, known as cancer stem cells, being attributed many important properties such as enhanced tumorigenicity, proliferation potential and profound multidrug resistance to chemotherapy. Several key stem cells markers were identified in colon cancer. In our study we focused on the aldehyde dehydrogenase type 1 (ALDH1) expression in colon cancer-derived cell lines HT-29/eGFP, HCT-116/eGFP and LS-180/eGFP, and its role in the chemoresistance and tumorigenic potential.

Methods

The effect of pharmacological inhibition of ALDH activity by diethylaminobenzaldehyde (DEAB) and also effect of molecular inhibition by specific siRNA was evaluated in vitro in cultures of human colorectal cell lines. The expression level of different isoenzymes of aldehyde dehydrogenase was determined using qPCR. Changes in cell biology were evaluated by expression analysis, western blot and apoptosis assay. The efficiency of cytotoxic treatment in the presence of different chemotherapeutic drugs was analyzed by fluorimetric assay. Tumorigenicity of cells with specific ALDH1A1 siRNA was tested in xenograft model in vivo.

Results

Treatment by DEAB partially sensitized the tested cell lines to chemotherapeutics. Subsequently the molecular inhibition of specific isoforms of ALDH by ALDH1A1 or ALDH1A3 siRNA led to sensitizing of cell lines HT-29/eGFP, HCT-116/eGFP to capecitabine and 5-FU. On the model of athymic mice we observed the effect of molecular inhibition of ALDH1A1 in HT-29/eGFP cells by siRNA. We observed inhibition of proliferation of subcutaneous xenografts in comparison to control cells.

Conclusion

This research, verifies the significance of the ALDH1A isoforms in multidrug resistance of human colorectal cancer cells and its potential as a cancer stem cell marker. This provides the basis for the development of new approaches regarding the treatment of patients with colorectal adenocarcinoma and potentially the treatment of other tumor malignancies.

Uncovering the Binding Specificities of Lectins with Cells for Precision Colorectal Cancer Diagnosis Based on Multimodal Imaging

There is a high desire for novel targets/biomarkers to diagnose and treat colorectal cancer (CRC). Here, an approach starting from a polyacrylamide hydrogel-based lectin microarray is presented to screen the high expression of glycans on the CRC cell surface and to identify new lectin biomarkers for CRC. Three common CRC cell lines (SW480, SW620, and HCT116) and one normal colon cell line (NCM460) are profiled on the microarray with 27 lectins. The experimental results reveal that CRC cells highly express the glycans with d-galactose, d-glucose, and/or sialic acid residues, and Uelx Europaeus Agglutinin-I (UEA-I) exhibits reasonable specificity with SW480 cells. After conjugation of UEA-I with silica-coated NaGdF4:Yb3+, Er3+@NaGdF4 upconversion nanoparticles, the follow-up in vitro and in vivo experiments provide further evidence on that UEA-I can serve as tumor-targeting molecule to diagnose SW480 tumor by multimodal imaging including upconversion luminescence imaging, T1-weighted magnetic resonance imaging, and X-ray computed tomography imaging.

Inhibition of Fas associated phosphatase 1 (Fap1) facilitates apoptosis of colon cancer stem cells and enhances the effects of oxaliplatin

Fas associated phosphatase 1 (Fap1) is a ubiquitously expressed protein tyrosine phosphatase. Fap1 substrates include Fas and Gsk3β, suggesting a role in regulating cell survival. Consistent with this, increased Fap1 expression is associated with resistance to Fas or platinum induced apoptosis in some human colon cancer tumors or cell lines. In the current studies, we found that Fap1 expression was significantly greater in CD133⁺ colon cancer stem cells compared to CD133⁻ tumor cells. PTPN13 promoter activity (encoding Fap1) was repressed by interferon regulatory factor 2 (irf2), and expression of Fap1 and Irf2 were inversely correlated in CD133⁺ or CD133⁻ colon cancer cells. We determined that CD133⁺ cells were relatively resistant to Fas or oxaliplatin induced apoptosis, but this was reversed by Fap1-knockdown or a Fap1-blocking tripeptide (SLV). In a murine xenograft model of colon cancer, we found treatment with SLV peptide significantly decreased tumor growth and relative abundance of CD133⁺CD44⁺ cells; associated with increased phosphorylation of Fap1 substrates. SLV peptide also enhanced inhibitory effects of oxaliplatin on tumor growth and Fap1 substrate phosphorylation in this model. Our studies suggest that therapeutically targeting Fap1 may decrease persistence of colon cancer stem cells during treatment with platinum chemotherapy by activating Fap1 substrates. In a murine model of chronic myeloid leukemia, we previously determined that inhibition of Fap1 decreased persistence of leukemia stem cells during tyrosine kinase inhibitor treatment. Therefore, Fap1 may be a tissue agnostic target to increase apoptosis in malignant stem cells.

Chemopreventive activity of celastrol in drug-resistant human colon carcinoma cell cultures

Celastrol (tripterine) a pentacyclic triterpenoid extracted from the roots of Tripterygium wilfordii Hook f., exhibits potent antioxidant and anti-inflammatory activity and also exerts important anti-cancer effects, as induction of apoptosis and lowering the level of drug resistance of several cancers. Increased level of cellular resistance to cytostatic drugs is typical for colorectal cancers, and largely determines the failure of chemotherapy for this tumor. The purpose of our research was to evaluate the chemopreventive effect of celastrol on cultures of colon cancer cells resistant to doxorubicin (LOVO/DX). With the use of flow cytometry we have shown that celastrol reduces the cell size of the SP (side population; subpopulation of cancer cells enriched with cancer stem cells), increases frequency of apoptosis and binds to Pgp protein in cell membranes inhibiting its transport function. The inhibition of the Pgp transport function has been shown to increase the accumulation of rhodamine-123 and standard cytostatic- doxorubicin in LOVO/DX cells. Our results prove that celastrol exhibits significant chemopreventive and chemosensitizing activities on drug resistant colon cancer cells. Celastrol appears to be a good candidate for adjuvant medicine that can improve the effectiveness of standard cytostatic therapy in humans.

Anti-EGFR antibody sensitizes colorectal cancer stem-like cells to Fluorouracil-induced apoptosis by affecting autophagy

Recent reports suggest that colorectal carcinoma (CRC) may be sustained by a small subpopulation of cells, termed cancer stem cells (CSCs), which have drug resistance properties as a key reason for chemotherapy failure. The epidermal growth factor receptor (EGFR) controls CRC initiation and progression. Monoclonal antibody against EGFR (cetuximab) has been used in treatment of several cancers. However, the effects of cetuximab on CSCs in the CRC chemotherapy remain unclear. Here, we studied the effects of cetuximab on the CSC-like cells in Fluorouracil (5-FU)-treated CRC cells. CSC-like cells were independently isolated from CRC cells using CD133, CD44 or EphB2-high as markers and confirmed by tumor sphere formation assay. We found that 5-FU increased the apoptotic death of CSC-like CRC cells. Co-application of cetuximab augmented the apoptotic death of CSC-like CRC cells by 5-FU, seemingly through inhibition of 5-FU-induced increases in cell autophagy in CSC-like CRC cells. Together, our data suggest that EGFR monoclonal antibody may sensitize CSC-like CRC cells to 5-FU-induced apoptosis by affecting autophagy.

The glycosyltransferase ST6Gal-I is enriched in cancer stem-like cells in colorectal carcinoma and contributes to their chemo-resistance

PURPOSE

Presence of cancer stem cells (CSCs) contributes to tumor outgrowth, chemo-resistance and relapse in some cancers including colorectal carcinoma (CRC). The current characterization methods of CSCs in CRC only allows enrichment of CSCs but not their purification. Recent reports showed that ST6 beta-galactoside alpha-2,6-sialyltransferase 1 (ST6Gal-I) plays an essential role in protecting tumor cells against harsh environment like oxidative stress and nutrient deprivation. Therefore, whether ST6Gal-I may be highly expressed in CSCs or whether it may enhance resistance of tumor cells to chemotherapy deserves exploration.

METHOD

ST6Gal-I levels were determined in CRC specimens, compared to paired normal colorectal tissue, and examined in CD133+ vs CD133- CRC cells, and CD44+ vs CD44- CRC cells. ST6Gal-I levels and their association with patient survival were examined. In vivo, 2 CRC cell lines Caco-2 and SW48 were transduced with two lentiviruses, one lentivirus carrying a green fluorescent protein reporter and a luciferase reporter under a cytomegalovirus promoter to allow tracing tumor cells by both fluorescence and luciferase activity, and one lentivirus carrying a nuclear red fluorescent protein under the control of ST6Gal-I promoter to allow separation of ST6Gal-I+ vs ST6Gal-I- CRC cells. Tumor sphere formation, resistance to fluorouracil-induced apoptosis, and frequency of tumor formation after serial adoptive transplantation were done on ST6Gal-I+ vs ST6Gal-I- CRC cells.

RESULT

ST6Gal-I levels were significantly upregulated in clinically obtained CRC specimens, compared to paired normal colorectal tissue. Poorer patient survival was detected in ST6Gal-I-high CRC, compared to ST6Gal-I-low subjects. Higher levels of ST6Gal-I were detected in CD133+ CRC cells than CD133- CRC cells, and in CD44+ CRC cells than in CD44- CRC cells. Compared to ST6Gal-I- CRC cells, ST6Gal-I+ CRC cells generated significantly more tumor spheres in culture, were more resistant to fluorouracil-induced apoptosis likely through upregulating cell autophagy, and generated tumor more frequently after serial adoptive transplantation.

CONCLUSION

ST6Gal-I may be highly expressed in the cancer stem-like cells in CRC and enhances cancer cell resistance to chemotherapy.

Drug resistance related to aberrant glycosylation in colorectal cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths in the world. Drug resistance of tumour cells remains the main challenge toward curative treatments efficiency. Several epidemiologic studies link emergence and recurrence of this cancer to metabolic disorders. Glycosylation that modifies more than 80% of human proteins is one of the most widepread nutrient-sensitive post-translational modifications. Aberrant glycosylation participates in the development and progression of cancer. Thus, some of these glycan changes like carbohydrate antigen CA 19-9 (sialyl Lewis a, sLea) or those found on carcinoembryonic antigen (CEA) are already used as clinical biomarkers to detect and monitor CRC. The current review highlights emerging evidences accumulated mainly during the last decade that establish the role played by altered glycosylations in CRC drug resistance mechanisms that induce resistance to apoptosis and activation of signaling pathways, alter drug absorption and metabolism, and led to stemness acquisition. Knowledge in this field of investigation could aid to the development of better therapeutic approaches with new predictive biomarkers and targets tied in with adapted diet.

Bcl-2 Antiapoptotic Family Proteins and Chemoresistance in Cancer

Cancer is a daunting global problem confronting the world's population. The most frequent therapeutic approaches include surgery, chemotherapy, radiotherapy, and more recently immunotherapy. In the case of chemotherapy, patients ultimately develop resistance to both single and multiple chemotherapeutic agents, which can culminate in metastatic disease which is a major cause of patient death from solid tumors. Chemoresistance, a primary cause of treatment failure, is attributed to multiple factors including decreased drug accumulation, reduced drug-target interactions, increased populations of cancer stem cells, enhanced autophagy activity, and reduced apoptosis in cancer cells. Reprogramming tumor cells to undergo drug-induced apoptosis provides a promising and powerful strategy for treating resistant and recurrent neoplastic diseases. This can be achieved by downregulating dysregulated antiapoptotic factors or activation of proapoptotic factors in tumor cells. A major target of dysregulation in cancer cells that can occur during chemoresistance involves altered expression of Bcl-2 family members. Bcl-2 antiapoptotic molecules (Bcl-2, Bcl-xL, and Mcl-1) are frequently upregulated in acquired chemoresistant cancer cells, which block drug-induced apoptosis. We presently overview the potential role of Bcl-2 antiapoptotic proteins in the development of cancer chemoresistance and overview the clinical approaches that use Bcl-2 inhibitors to restore cell death in chemoresistant and recurrent tumors.

Targeted photodynamic therapy as potential treatment modality for the eradication of colon cancer and colon cancer stem cells

Colorectal cancer is commonly treated by tumour resection, as chemotherapy and radiation have proven to be less effective, especially if the tumour has metastasized. Resistance to therapies occurs in almost all patients with colorectal cancer, especially in those with metastatic tumours. Cancer stem cells have the ability to self-renew, and their slow rate of cycling enhances resistance to treatment and increases the likelihood of tumour recurrence. Most metastatic tumours are unable to be surgically removed, thus creating a need for treatment modalities that target cancers directly and destroy cancer stem cells. Photodynamic therapy involves a photosensitizer that when exposed to a light source of a particular wavelength becomes excited and produces a form of oxygen that kills cancer cells. Photodynamic therapy is currently being investigated as a treatment modality for colorectal cancer, and new studies are exploring enhancing photodynamic therapy efficacy with the aid of drug carriers and immune conjugates. These modifications could prove effective in targeting cancer stem cells that are thought to be resistant to photodynamic therapy. In order for photodynamic therapy to be an effective treatment in colorectal cancer, it requires treatment of both primary tumours and the metastatic secondary disease that is caused by colon cancer stem cells. This review focuses on current photodynamic therapy treatments available for colorectal cancer and highlights proposed actively targeted photosynthetic drug uptake mechanisms specifically mediated towards colon cancer stem cells, as well as identify the gaps in research which need to be investigated in order to develop a combinative targeted photodynamic therapy regime that can effectively control colorectal cancer primary and metastatic tumour growth by eliminating colon cancer stem cells.

CD133-targeted oncolytic adenovirus demonstrates anti-tumor effect in colorectal cancer

Oncolytic Adenoviruses (OAds) are one of the most promising anti-cancer agents that can induce cancer specific cell death. Recently, we generated infectivity-selective OAd, and the resultant OAd tumor-specific binding shows strong efficacy and mitigates toxicity. In this study, we applied this strategy based on adenovirus library screening system for generation of CD133-targeted OAd, and examined their oncolytic activity against colorectal cancer (CRC) in vitro and in vivo. CD133 (Prominin-1) is an important cell surface marker of cancer stem (like) cells (CSCs) in various cancers, including CRC. Elimination of CSCs has a high likelihood to improve CRC treatment because CSCs population in the tumor contributes to recurrence, metastases, chemotherapy resistance, and poor survival. The OAd with CD133-targeting motif (AdML-TYML) selectively infected CD133⁺ cultured cells and lysed them efficiently. Treatment with AdML-TYML prior to tumor inoculation inhibited the establishment of tumor of CD133⁺ CRC cell lines in nude mice. AdML-TYML also showed strong antitumor effect after intratumoral injections in already established CD133⁺ CRC subcutaneous xenografts. Our results indicate that CD133-targeted OAd selectively infected CD133⁺ CRC, and exhibited anti-tumorigenicity and therapeutic effect in established tumors. This novel infectivity selective virus could be a potent tool for the prevention of metastases and relapses in CRC.

Flt-1-positive cells are cancer-stem like cells in colorectal carcinoma

Recent evidence demonstrates an essential role of cancer stem cells (CSCs) in cancer initiation, progression, migration, metastasis as well as chemo-resistance. Nevertheless, identification of CSCs in different cancers has not been succeeded, since such CSCs are typically lack of a specific and unique marker. Therefore, the current strategy is basically using one or several markers to enrich CSCs, or to isolate CSC-like cells. Here, we showed that in clinically obtained colorectal carcinoma (CRC) specimens, Flt-1, the type 1 receptor for vascular endothelial growth factor A, was significantly upregulated. Moreover, more distal metastasis and poorer patient survival were detected in Flt-1^high CRC, compared to Flt1^low subjects. Two CRC cell lines were then labeled with both luciferase and red fluorescent protein (RFP) reporters. We found that in both lines, compared to Flt-1- CRC cells, Flt-1+ CRC cells generated significantly more tumor spheres in culture, appeared to be more resistant to fluorouracil-induced apoptosis, were more detectable in the circulation after subcutaneous transplantation, and had a higher chances to generate tumor after serial adoptive transplantation. Thus, we conclude that Flt-1 may be used as a surface marker to enrich CSC in CRC. Selective elimination of Flt-1+ CRC cells may improve the therapeutic outcome.

CD133-targeted oncolytic adenovirus demonstrates anti-tumor effect in colorectal cancer

Oncolytic Adenoviruses (OAds) are one of the most promising anti-cancer agents that can induce cancer specific cell death. Recently, we generated infectivity-selective OAd, and the resultant OAd tumor-specific binding shows strong efficacy and mitigates toxicity. In this study, we applied this strategy based on adenovirus library screening system for generation of CD133-targeted OAd, and examined their oncolytic activity against colorectal cancer (CRC) in vitro and in vivo. CD133 (Prominin-1) is an important cell surface marker of cancer stem (like) cells (CSCs) in various cancers, including CRC. Elimination of CSCs has a high likelihood to improve CRC treatment because CSCs population in the tumor contributes to recurrence, metastases, chemotherapy resistance, and poor survival. The OAd with CD133-targeting motif (AdML-TYML) selectively infected CD133+ cultured cells and lysed them efficiently. Treatment with AdML-TYML prior to tumor inoculation inhibited the establishment of tumor of CD133+ CRC cell lines in nude mice. AdML-TYML also showed strong antitumor effect after intratumoral injections in already established CD133+ CRC subcutaneous xenografts. Our results indicate that CD133-targeted OAd selectively infected CD133+ CRC, and exhibited anti-tumorigenicity and therapeutic effect in established tumors. This novel infectivity selective virus could be a potent tool for the prevention of metastases and relapses in CRC.

The role of pparγ and autophagy in ros production, lipid droplets biogenesis and its involvement with colorectal cancer cells modulation

Background

In cancer cells, autophagy can act as both tumor suppressor, when autophagic event eliminates cellular contends which exceeds the cellular capacity of regenerate promoting cell death, and as a pro-survival agent removing defective organelles and proteins and helping well-established tumors to maintain an accelerated metabolic state while still dealing with harsh conditions, such as inflammation. Many pathways can coordinate the autophagic process and one of them involves the transcription factors called PPARs, which also regulate cellular differentiation, proliferation and survival. The PPARγ activation and autophagy initiation seems to be interrelated in a variety of cell types.

Methods

Caco-2 cells were submitted to treatment with autophagy and PPARγ modulators and the relationship between both pathways was determined by western blotting and confocal microscopy. The effects of such modulations on Caco-2 cells, such as lipid bodies biogenesis, cell death, proliferation, cell cycle, ROS production and cancer stem cells profiling were analyzed by flow cytometry.

Results

PPARγ and autophagy pathways seem to be overlap in Caco-2 cells, modulating each other in different ways and determining the lipid bodies biogenesis. In general, inhibition of autophagy by 3-MA leaded to reduced cell proliferation, cell cycle arrest and, ultimately, cell death by apoptosis. In agreement with these results, ROS production was increased in 3-MA treated cells. Autophagy also seems to play an important role in cancer stem cells profiling. Rapamycin and 3-MA induced epithelial and mesenchymal phenotypes, respectively.

Conclusions

This study helps to elucidate in which way the induction or inhibition of these pathways regulate each other and affect cellular properties, such as ROS production, lipid bodies biogenesis and cell survive. We also consolidate autophagy as a key factor for colorectal cancer cells survival in vitro, pointing out a potential side effect of autophagic inhibition as a therapeutic application for this disease and demonstrate a novel regulation of PPARγ expression by inhibition of PI3K III.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0451-5) contains supplementary material, which is available to authorized users.

SATB2/β-catenin/TCF-LEF pathway induces cellular transformation by generating cancer stem cells in colorectal cancer

Recent studies have demonstrated the involvement of colorectal cancer (CRC) stem cells (CSC) in transformation, cancer progression and metastasis. The main goal of this paper was to examine the molecular mechanisms by which SATB2 induced malignant transformation of colorectal epithelial cells. SATB2 induced malignant transformation and these transformed cells gained the characteristics of CSCs by expressing stem cell markers (CD44, CD133, LGR5 and DCLK1) and transcription factors (c-Myc, Nanog and Sox2). Overexpression of SATB2 in normal colorectal epithelial cells increased cell motility, migration and invasion, which were associated with an increase in N-cadherin and Zeb1, and decrease in E-cadherin expression. SATB2 overexpression also upregulated XIAP and cyclin D1, suggesting its role in cell survival and cell cycle. Furthermore, the expression of SATB2 was positively correlated with β-catenin expression in CRC. In contrary, depletion of SATB2 inhibited cell proliferation, colony formation, cell motility and expression of β-catenin, Snail, Slug, Zeb1 and N-cadherin, and upregulated E-cadherin. Furthermore, SATB2 silencing inhibited the expression of stem cell markers, pluripotency maintaining transcription factors, cell cycle and cell proliferation/survival genes and TCF/LEF targets. Finally, β-catenin/TCF-LEF pathway mediated the biological effects of SATB2 in CSCs. These studies support the role of SATB2/β-catenin/TCF-LEF pathway in transformation and carcinogenesis.

SATB2/β-catenin/TCF-LEF pathway induces cellular transformation by generating cancer stem cells in colorectal cancer

Recent studies have demonstrated the involvement of colorectal cancer (CRC) stem cells (CSC) in transformation, cancer progression and metastasis. The main goal of this paper was to examine the molecular mechanisms by which SATB2 induced malignant transformation of colorectal epithelial cells. SATB2 induced malignant transformation and these transformed cells gained the characteristics of CSCs by expressing stem cell markers (CD44, CD133, LGR5 and DCLK1) and transcription factors (c-Myc, Nanog and Sox2). Overexpression of SATB2 in normal colorectal epithelial cells increased cell motility, migration and invasion, which were associated with an increase in N-cadherin and Zeb1, and decrease in E-cadherin expression. SATB2 overexpression also upregulated XIAP and cyclin D1, suggesting its role in cell survival and cell cycle. Furthermore, the expression of SATB2 was positively correlated with β-catenin expression in CRC. In contrary, depletion of SATB2 inhibited cell proliferation, colony formation, cell motility and expression of β-catenin, Snail, Slug, Zeb1 and N-cadherin, and upregulated E-cadherin. Furthermore, SATB2 silencing inhibited the expression of stem cell markers, pluripotency maintaining transcription factors, cell cycle and cell proliferation/survival genes and TCF/LEF targets. Finally, β-catenin/TCF-LEF pathway mediated the biological effects of SATB2 in CSCs. These studies support the role of SATB2/β-catenin/TCF-LEF pathway in transformation and carcinogenesis.

Primary patient-derived lung adenocarcinoma cell culture challenges the association of cancer stem cells with epithelial-to-mesenchymal transition

The cancer stem cell (CSC) and epithelial-to-mesenchymal transition (EMT) models have been closely associated and used to describe both the formation of metastasis and therapy resistance. We established a primary lung cell culture from a patient in a clinically rare and unique situation of primary resistant disease. This culture consisted of two biologically profoundly distinct adenocarcinoma cell subpopulations, which differed phenotypically and genotypically. One subpopulation initiated and sustained in spheroid cell culture (LT22s) whereas the other subpopulation was only capable of growth and proliferation under adherent conditions (LT22a). In contrast to our expectations, LT22s were strongly associated with the epithelial phenotype, and expressed additionally CSC markers ALDH1 and CD133, whereas the LT22a was characterized as mesenchymal with lack of CSC markers. The LT22s cells also demonstrated an invasive behavior and mimicked gland formation. Finally, LT22s were more resistant to Cisplatin than LT22a cells. We demonstrate a primary lung adenocarcinoma cell culture derived from a patient with resistant disease, with epithelial aggressive subpopulation of cells associated with stem cell features and therapy resistance. Our findings challenge the current model associating CSC and disease resistance mainly to mesenchymal cells and may have important clinical implications.

Inflammation and Colorectal Cancer

Colorectal cancer (CRC) is the fourth most common cancer in both men and women in the United States, resulting in over 55,000 deaths annually. Environmental and genetic factors influence the development of CRC, and inflammation is a critical hallmark of cancer that may arise from a variety of factors.

PURPOSE OF REVIEW

While patients with inflammatory bowel disease (IBD) have a higher risk of developing CRC, sporadic CRCs may engender or be potentiated by inflammation as well. In this review, we focus on recent advances in basic and translational research utilizing murine models to understand the contribution of inflammatory signaling pathways to CRC.

RECENT FINDINGS

We discuss advances in the utility of three-dimensional enteroid/colonoid/tumoroid cultures to understand immune-epithelial interactions in CRC, as well as the potential for utilizing patient-derived tumoroids for personalized therapies.

SUMMARY

This review underscores the importance of understanding the complex molecular mechanisms underlying inflammation in sporadic CRC and highlights up-and-coming or new avenues for CRC biomarkers or therapies.

Synergy between Auraptene, Ionizing Radiation, and Anticancer Drugs in Colon Adenocarcinoma Cells

Colorectal cancer is a growing health concern with increasing mortality rates, and resistance to anticancer drugs and radiotherapy is a serious drawback in its treatment. Auraptene is a natural prenyloxycoumarin with valuable anticancer effects. The aim of current study was to determine the synergy between auraptene, ionizing radiation, and chemotherapeutic drugs in colon adenocarcinoma cells for the first time. To do so, HT29 cells were treated with combination of auraptene + cisplatin, + doxorubicin, or + vincristine. Furthermore, cells were pretreated with nontoxic auraptene and then exposed to various doses of X-radiation. Assessment of cell viability not only indicated significant (p < 0.05) synergic effects of auraptene and anticancer agents, also revealed more significant (p < 0.01) increase in the toxicity of applied radiations in auraptene pretreated cells. Interesting synergy between auraptene and radiotherapy was then confirmed by morphological alterations, DAPI staining, and flow cytometric analysis of the cell cycle. Moreover, real-time reverse transcription polymerase chain reaction analysis indicated significant (p < 0.01) overexpression of p21, but not GATA6, in auraptene pretreated cells after radiotherapy, and also significant (p < 0.01) down regulation of CD44 and ALDH1 by auraptene. According to present results, auraptene could be considered as an effective natural coumarin to improve the outcome of current chemoradiotherapy options. Copyright © 2017 John Wiley & Sons, Ltd.