Overview of biomarkers in metastatic colorectal cancer: tumour, blood and patient-related factors

BioMOF-Based Anti-Cancer Drug Delivery Systems

A variety of nanomaterials have been developed specifically for biomedical applications, such as drug delivery in cancer treatment. These materials involve both synthetic and natural nanoparticles and nanofibers of varying dimensions. The efficacy of a drug delivery system (DDS) depends on its biocompatibility, intrinsic high surface area, high interconnected porosity, and chemical functionality. Recent advances in metal-organic framework (MOF) nanostructures have led to the achievement of these desirable features. MOFs consist of metal ions and organic linkers that are assembled in different geometries and can be produced in 0, 1, 2, or 3 dimensions. The defining features of MOFs are their outstanding surface area, interconnected porosity, and variable chemical functionality, which enable an endless range of modalities for loading drugs into their hierarchical structures. MOFs, coupled with biocompatibility requisites, are now regarded as highly successful DDSs for the treatment of diverse diseases. This review aims to present the development and applications of DDSs based on chemically-functionalized MOF nanostructures in the context of cancer treatment. A concise overview of the structure, synthesis, and mode of action of MOF-DDS is provided.

Preclinical Molecular PET-CT Imaging Targeting CDCP1 in Colorectal Cancer

Colorectal cancer (CRC) is the third most common malignancy in the world, with 22% of patients presenting with metastatic disease and a further 50% destined to develop metastasis. Molecular imaging uses antigen-specific ligands conjugated to radionuclides to detect and characterise primary cancer and metastases. Expression of the cell surface protein CDCP1 is increased in CRC, and here we sought to assess whether it is a suitable molecular imaging target for the detection of this cancer. CDCP1 expression was assessed in CRC cell lines and a patient-derived xenograft to identify models suitable for evaluation of radio-labelled 10D7, a CDCP1-targeted, high-affinity monoclonal antibody, for preclinical molecular imaging. Positron emission tomography-computed tomography was used to compare zirconium-89 (⁸⁹Zr)-10D7 avidity to a nonspecific, isotype control ⁸⁹Zr-labelled IgGκ1 antibody. The specificity of CDCP1-avidity was further confirmed using CDCP1 silencing and blocking models. Our data indicate high avidity and specificity for of ⁸⁹Zr-10D7 in CDCP1 expressing tumors at. Significantly higher levels than normal organs and blood, with greatest tumor avidity observed at late imaging time points. Furthermore, relatively high avidity is detected in high CDCP1 expressing tumors, with reduced avidity where CDCP1 expression was knocked down or blocked. The study supports CDCP1 as a molecular imaging target for CRC in preclinical PET-CT models using the radioligand ⁸⁹Zr-10D7.

miR‑1 inhibits the progression of colon cancer by regulating the expression of vascular endothelial growth factor

MicroRNA (miR)-1 is associated with various human malignancies through repressing tumor growth, migration and angiogenesis. Recently, high-throughput transcriptional profiling confirmed that miR-1 is markedly downregulated in metastatic colorectal cancer; however, its biological functions and the specific underlying mechanisms in colorectal cancer (CRC) require further investigation. In this study, the expression of miR-1 in 111 CRC and paired normal tissue samples was measured using quantitative polymerase chain reaction analysis, and the association between miR-1 expression and clinical characteristics was evaluated. miR-1 was found to be significantly downregulated in CRC tissues compared with paired normal tissues, and in CRC cell lines compared with non-cancer cells (P<0.001), and was negatively associated with tumor size (P=0.001), differentiation (P=0.011), lymph node metastasis (P=0.001) and TNM stage (P=0.001). Further experiments revealed that miR-1 inhibited the migration and invasion of HCT116 and ClonA1 cells, and inhibited cell proliferation by affecting the cell cycle. Vascular endothelial growth factor (VEGF) was found to be a potential target of miR-1 by biological prediction, and further investigation confirmed that miR-1 significantly inhibited the expression and paracrine function of VEGF. In CRC tissues, the expression of VEGF was negatively correlated with miR-1. The low expression of miR-1 in CRC may be one of the reasons for the abnormally high expression of VEGF; the upregulation of miR-1 expression may inhibit cancer progression by downregulating VEGF. These findings indicate that treatment with miR-1 may be a novel method of tumor suppression, and provide a theoretical and experimental basis for the further targeted treatment of CRC through the regulation of miR-1 and VEGF expression.

Characterisation of the oxysterol metabolising enzyme pathway in mismatch repair proficient and deficient colorectal cancer

Oxysterols are oxidised derivatives of cholesterol, formed by the enzymatic activity of several cytochrome P450 enzymes and tumour-derived oxysterols have been implicated in tumour growth and survival. The aim of this study was to profile the expression of oxysterol metabolising enzymes in primary colorectal cancer and assess the association between expression and prognosis.

Immunohistochemistry was performed on a colorectal cancer tissue microarray containing 650 primary colorectal cancers using monoclonal antibodies to CYP2R1, CYP7B1, CYP8B1, CYP27A1, CYP39A1, CYP46A1 and CYP51A1, which we have developed. Unsupervised hierarchical cluster analysis was used to examine the overall relationship of oxysterol metabolising enzyme expression with outcome and based on this identify an oxysterol metabolising enzyme signature associated with prognosis.

Cluster analysis of the whole patient cohort identified a good prognosis group (mean survival=146 months 95% CI 127-165 months) that had a significantly better survival (δ²=12.984, p<0.001, HR=1.983, 95% CI 1.341-2.799) than the poor prognosis group (mean survival=107 months, 95% CI 98-123 months). For the mismatch repair proficient cohort, the good prognosis group had a significantly better survival (δ²=8.985, p=0.003, HR=1.845, 95% CI 1.227-2.774) than the poor prognosis group. Multi-variate analysis showed that cluster group was independently prognostically significant in both the whole patient cohort (p=0.02, HR=1.554, 95% CI 1.072-2.252) and the mismatch repair proficient group (p=0.04, HR=1.530, 95% CI 1.014-2.310).

Individual oxysterol metabolising enzymes are overexpressed in colorectal cancer and an oxysterol metabolising enzyme expression profile associated with prognosis has been identified in the whole patient cohort and in mismatch repair proficient colorectal cancers.

Role of Biologics in First-Line Treatment of Colorectal Cancer

In the past decade, significant advances have been made in the treatment of advanced colorectal cancer. Multiple cytotoxic agents and targeted therapies have been approved for management of metastatic colorectal cancer, leading to improvement of median overall survival in clinical trials to more than 30 months. Of note, before the introduction of biologics into treatment algorithms for metastatic colorectal cancer, median survival in phase III trials never exceeded 24 months. In 2016, the most common treatment approach in first line is a combination of chemotherapy with a biologic agent. The choice of therapy is influenced by patient factors (eg, age, comorbidities), tumor characteristics (eg, overall tumor burden, pattern of metastatic spread, mutation signature), potential adverse effects of therapy, and goals of treatment. The choice between irinotecan- or oxaliplatin-based cytotoxic chemotherapy regimen is primarily based on differential toxicity profile because they have similar efficacy. Currently, three biologic agents-bevacizumab, cetuximab, and panitumumab-are approved for first-line treatment of metastatic colorectal cancer. For patients with mutant RAS and likely mutant BRAF V600E tumors, bevacizumab is the only biologic agent that can be used in conjunction with cytotoxic chemotherapy. The choice of anti-epidermal growth factor antibody or anti-vascular endothelial growth factor antibody in RAS wild-type tumors is based on the specific clinical scenario. Recently, some clinical and molecular biomarkers have emerged that may help in decision making. In this review, we discuss the role of biologics in the management of first-line treatment of metastatic colorectal cancer.

Differential Immune Reactivity Pattern of SW48 and SW1116 Colorectal Cancer Cell Lines with Colorectal Cancer Patients Sera

BACKGROUND

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide. It is also known as the second leading cause of deaths as the early stage detection is not yet available by current methods. So identification of biomarkers can also be functional in early diagnosis and prognosis.

MATERIALS AND METHODS

We examined sera from 60 CRC patients of different stages as a source of auto-antibody as well as two human CRC cell lines with different invasive capacities (SW48 and SW1116) as the source of antigens. The pattern of immune reactivity in immuneblotting tests between mentioned cell lines and CRC patients' sera were evaluated by ImageJ software.

RESULTS

The Immune reactivity pattern of two cell lines (SW48 and SW1116) with CRC patients' sera were different in band intensities and the most immune reactivity intensity was observed in SW48 cell lysate with sera from Stage III CRC patients.

CONCLUSION

Due to the humoral immune response, sera from Stage III CRC patients contained autoantibodies that demonstrated higher immune reactivity. Moreover, SW48 cell line with high aggressive behavior reacted to CRC patients' sera with greater intensity compared with less aggressive behavior cell line (SW1116). Therefore, it is required to use other techniques such as two-dimensional electrophoresis and mass spectrometry.

Ultrasensitive electrochemical aptasensor based on sandwich architecture for selective label-free detection of colorectal cancer (CT26) cells

Colorectal cancer is one of the most common cancers in the world and has no effective treatment. Therefore, development of new methods for early diagnosis is instantly required. Biological recognition probes such as synthetic receptor and aptamer is one of the candidate recognition layers to detect important biomolecules. In this work, an electrochemical aptasensor was developed by fabricating an aptamer-cell-aptamer sandwich architecture on an SBA-15-3-aminopropyltriethoxysilane (SBA-15-pr-NH₂) and Au nanoparticles (AuNPs) modified graphite screen printed electrode (GSPE) surface for the selective, label-free detection of CT26 cancer cells. Based on the incubation of the thiolated aptamer with CT26 cells, the electron-transfer resistance of Fe (CN)₆^3-/4- redox couple increased considerably on the aptasensor surface. The results obtained from cyclic voltammetry and electrochemical impedance spectroscopy studies showed that the fabricated aptasensor can specifically identify CT26 cells in the concentration ranges of 10-1.0×10⁵cells/mL and 1.0×10⁵-6.0×10⁶ cells/mL, respectively, with a detection limit of 2cells/mL. Applying the thiol terminated aptamer (5TR1) as a recognition layer led to a sensor with high affinity for CT26 cancer cells, compared to control cancer cells of AGS cells, VERO Cells, PC3 cells and SKOV-3 cells. Therefore a simple, rapid, label free, inexpensive, excellent, sensitive and selective electrochemical aptasensor based on sandwich architecture was developed for detection of CT26 Cells.

Gemcitabine-based polymer-drug conjugate for enhanced anticancer effect in colon cancer

In this study, we have demonstrated gemcitabine (GEM)-conjugated amphiphilic biodegradable polymeric drug carriers. Our aim was to increase the chemotherapeutic potential of GEM in colon cancer by forming a unique polymer-drug conjugates. The polymer-drug conjugate micelles were nanosized with a typical spherical shape. The GEM-conjugated methoxy poly(ethylene glycol)-poly(lactic acid) (GEM-PL) exhibited a controlled release of drug in both the pH conditions. The developed GEM-PL efficiently killed the HT29 cancers cells in a typical time dependent manner. The clonogenic assay further confirmed the superior anticancer effect of GEM-PL which showed least number of colonies. GEM-PL formulation exhibited a significantly higher apoptosis of cancer cells (∼25%) when stained using Annexin-V/PI kit. Conjugation of GEM to the mPEG-PLA significantly enhanced the blood circulation potential in animal model compared to that of free GEM. GEM-PL could prevent quick elimination of the drug and can provide sufficient time for the greater accumulation of GEM at the tumor sites. GEM-PL showed a remarkable tumor regression effect as evident from the lowest tumor volume in HT-29 containing tumor model. Overall, mPEG-PLA/GEM conjugates showed the potential of polymer-based drug targeting and might hold significant clinical potential in the treatment of colon cancers.

Stratifying risk of recurrence in stage II colorectal cancer using deregulated stromal and epithelial microRNAs

MicroRNAs (miRNAs) enable colonic epithelial cells to acquire malignant characteristics and metastatic capabilities. Recently, cancer relevant miRNAs deregulated during disease progression have also been identified in tumor-associated stroma.By combining laser-microdissection (LMD) with high-throughput screening and high-sensitivity quantitation techniques, miRNA expression in colorectal cancer (CRC) specimens and paired normal colonic tissue was independently characterized in stromal and epithelial tissue compartments. Notably, deregulation of the key oncogene miR-21 was identified exclusively as a stromal phenomenon and miR-106a, an epithelial phenomenon in the malignant state.MiRNAs identified in this study successfully distinguished CRC from normal tissue and metastatic from non-metastatic tumor specimens. Furthermore, in a separate cohort of 50 consecutive patients with CRC, stromal miR-21 and miR-556 and epithelial miR-106a expression predicted short disease free survival (DFS) and overall survival (OS) in stage II disease: miR-21 (DFS: HR = 2.68, p = 0.015; OS: HR = 2.47, p = 0.029); miR-556 (DFS: HR = 2.60, p = 0.018); miR-106a (DFS: HR = 2.91, p = 0.008; OS: HR = 2.25, p = 0.049); combined (All High vs. All Low. DFS: HR = 5.83, p = 0.002; OS: HR = 4.13, p = 0.007).These data support the notion that stromal as well as epithelial miRNAs play important roles during disease progression, and that mapping patterns of deregulated gene expression to the appropriate tumor strata may be a valuable aid to therapeutic decision making in CRC.

Prognostic factors in relation to racial disparity in advanced colorectal cancer survival

INTRODUCTION

Colorectal cancer mortality rates are significantly greater in AA than in EA individuals, and the disparity is worsening. We investigated the relationship between race and metastatic CRC (mCRC) survival in younger and older patients.

PATIENTS AND METHODS

Using data from the Hollings Cancer Center (Charleston, SC), we studied the role of clinical, pathologic, and treatment-related factors on the disparity in survival. We carried out a retrospective cohort study of 82 mCRC patients (26 AA, 56 EA). The data source was medical record data from June 1, 2004 through May 31, 2008 with follow-up through June 30, 2010. Using Kaplan-Meier methods, we generated median survival time according to race and age (< 61, ≥ 61 years). Cox proportional hazards regression models were used to model the risk of death according to race.

RESULTS

The median age was 56.7 years for AA and 61.6 years for EA patients. Compared with EA, median survival in AA patients was 59% worse in younger patients (12.7 vs. 31.0 months) and 29% worse in older patients (11.7 vs. 16.4 months). The risk of death among younger AA compared with EA patients was 2.45 (95% confidence interval [CI], 1.15-5.23) and among older patients was 1.16 (95% CI, 0.49-2.73).

CONCLUSION

Our results highlight the importance of considering younger age, clinical prognostic markers, and tumor phenotypes as potential sources of the disparity in advanced stage CRC.

The expression and prognostic significance of retinoic acid metabolising enzymes in colorectal cancer

Colorectal cancer is one of the most common types of cancer with over fifty percent of patients presenting at an advanced stage. Retinoic acid is a metabolite of vitamin A and is essential for normal cell growth and aberrant retinoic acid metabolism is implicated in tumourigenesis. This study has profiled the expression of retinoic acid metabolising enzymes using a well characterised colorectal cancer tissue microarray containing 650 primary colorectal cancers, 285 lymph node metastasis and 50 normal colonic mucosal samples. Immunohistochemistry was performed on the tissue microarray using monoclonal antibodies which we have developed to the retinoic acid metabolising enzymes CYP26A1, CYP26B1, CYP26C1 and lecithin retinol acyl transferase (LRAT) using a semi-quantitative scoring scheme to assess expression. Moderate or strong expression of CYP26A1was observed in 32.5% of cancers compared to 10% of normal colonic epithelium samples (p<0.001). CYP26B1 was moderately or strongly expressed in 25.2% of tumours and was significantly less expressed in normal colonic epithelium (p<0.001). CYP26C1 was not expressed in any sample. LRAT also showed significantly increased expression in primary colorectal cancers compared with normal colonic epithelium (p<0.001). Strong CYP26B1 expression was significantly associated with poor prognosis (HR = 1.239, 95%CI = 1.104-1.390, χ(2) = 15.063, p = 0.002). Strong LRAT was also associated with poorer outcome (HR = 1.321, 95%CI = 1.034-1.688, χ(2) = 5.039, p = 0.025). In mismatch repair proficient tumours strong CYP26B1 (HR = 1.330, 95%CI = 1.173-1.509, χ(2)= 21.493, p<0.001) and strong LRAT (HR = 1.464, 95%CI = 1.110-1.930, χ(2) = 7.425, p = 0.006) were also associated with poorer prognosis. This study has shown that the retinoic acid metabolising enzymes CYP26A1, CYP26B1 and LRAT are significantly overexpressed in colorectal cancer and that CYP26B1 and LRAT are significantly associated with prognosis both in the total cohort and in those tumours which are mismatch repair proficient. CYP26B1 was independently prognostic in a multivariate model both in the whole patient cohort (HR = 1.177, 95%CI = 1.020-1.216, p = 0.026) and in mismatch repair proficient tumours (HR = 1.255, 95%CI = 1.073-1.467, p = 0.004).

Current opinion on optimal treatment for colorectal cancer

The medical treatment of colorectal cancer (CRC) has evolved greatly in the last 10 years, involving complex combined chemotherapy protocols and, in more recent times, new biologic agents. Advances in adjuvant therapy have been limited to the addition of oxaliplatin and the substitution of oral fluoropyrimidine (e.g., capecitabine) for intravenous 5-fluorouracil with no evidence for improved outcome with biological agents. Clinical benefit from the use of the targeted monoclonal antibodies, bevacizumab, cetuximab and panitumumab, in the treatment of metastatic CRC is now well established, but the optimal timing of their use requires careful consideration to derive the maximal benefit. Evidence to date suggests potentially distinct roles for bevacizumab and EGF receptor-targeted biological agents (cetuximab and panitumumab) in the treatment of metastatic CRC. This article reviews the evidence in support of modern treatments for CRC and the decision-making behind the treatment choices, their benefits and toxicities.

Epirubicin loaded super paramagnetic iron oxide nanoparticle-aptamer bioconjugate for combined colon cancer therapy and imaging in vivo

Every year a large number of new cases of colorectal cancer are diagnosed in the world. Application of Epirubicin (Epi) in treatment of cancer has been limited due to its cardiotoxicity. Specific delivery of chemotherapy drugs is an important factor in reducing the side effects of drugs used in chemotherapy. Enhanced permeability, retention effect and magnetic resonance (MR) traceability of super paramagnetic iron oxide nanoparticles (SPION) make them a great candidate in cancer therapy and imaging. In this study, Epirubicin-5TR1 aptamer-SPION tertiary complex was evaluated for the imaging and treatment of murine colon carcinoma cells (C26 cells, target). For cytotoxic studies (MTT assay), C26 and CHO-K1 (Chinese hamster ovary cells, nontarget) cells were treated with either Epi or Epi-Apt-SPION tertiary complex. Internalization was evaluated by flow cytometry. Finally, Apt-SPION bioconjugate was used for imaging of cancer in vivo. Flow cytometric analysis showed that the tertiary complex was internalized effectively to C26 cells, but not to CHO-K1 cells. Cytotoxicity of Epi-Apt-SPION tertiary complex also confirmed internalization data. The complex was less cytotoxic in CHO-K1 cells when compared to Epi alone. No significant change in viability between Epi- and complex-treated C26 cells was observed. Magnetic resonance imaging (MRI) indicated a high level of accumulation of the nano-magnets within the tumor site. In conclusion Epi-Apt-SPION tertiary complex is introduced as an effective system for targeted delivery of Epi to C26 cells. Moreover this complex could efficiently detect tumors when analyzed by MRI and inhibit tumor growth in vivo.