Peptide-Based Vaccine against Breast Cancer: Recent Advances and Prospects.

Breast cancer is considered the second-leading cancer after lung cancer and is the most prevalent cancer among women globally. Currently, cancer immunotherapy via vaccine has gained great attention due to specific and targeted immune cell activity that creates a potent immune response, thus providing long-lasting protection against the disease. Despite peptides being very susceptible to enzymatic degradation and poor immunogenicity, they can be easily customized with selected epitopes to induce a specific immune response and particulate with carriers to improve their delivery and thus overcome their weaknesses. With advances in nanotechnology, the peptide-based vaccine could incorporate other components, thereby modulating the immune system response against breast cancer. Considering that peptide-based vaccines seem to show remarkably promising outcomes against cancer, this review focuses on and provides a specific view of peptide-based vaccines used against breast cancer. Here, we discuss the benefits associated with a peptide-based vaccine, which can be a mainstay in the prevention and recurrence of breast cancer. Additionally, we also report the results of recent trials as well as plausible prospects for nanotechnology against breast cancer.

Methylation Profile of Cancer Testis Antigens in Colorectal Cancer.

Background: Cancer testis antigens (CTAs) are a class of immune-stimulating antigens often overexpressed in many types of cancers. The usage of the CTAs as immunotherapy targets have been widely investigated in different cancers including melanoma, hematological malignancies, and colorectal cancer. Studies have indicated that the epigenetic regulation of the CTAs such as the methylation status may affect the expression of the CTAs. However, the report on the methylation status of the CTAs is conflicting. The general methylation profile of the CTAs, especially in colorectal cancer, is still elusive. Objective: To determine the methylation profile of the selected CTAs in our colorectal cancer patients. Methods: A total of 54 pairs of colorectal cancer samples were subjected to DNA methylation profiling using the Infinium Human Methylation 450K bead chip. Results: We found that most of the CTAs were hypomethylated, and CCNA1 and TMEM108 genes were among the few CTAs that were hypermethylated. Conclusion: Overall, our brief report has managed to show the overall methylation profile in over the 200 CTAs in colorectal cancer and this could be used for further refining any immunotherapy targets.

Immunomodulatory effects of extracellular vesicles in glioblastoma.

Glioblastoma (GB) is a type of brain cancer that can be considered aggressive. Glioblastoma treatment has significant challenges due to the immune privilege site of the brain and the presentation of an immunosuppressive tumor microenvironment. Extracellular vesicles (EVs) are cell-secreted nanosized vesicles that engage in intercellular communication via delivery of cargo that may cause downstream effects such as tumor progression and recipient cell modulation. Although the roles of extracellular vesicles in cancer progression are well documented, their immunomodulatory effects are less defined. Herein, we focus on glioblastoma and explain the immunomodulatory effects of extracellular vesicles secreted by both tumor and immune cells in detail. The tumor to immune cells, immune cells to the tumor, and intra-immune cells extracellular vesicles crosstalks are involved in various immunomodulatory effects. This includes the promotion of immunosuppressive phenotypes, apoptosis, and inactivation of immune cell subtypes, which affects the central nervous system and peripheral immune system response, aiding in its survival and progression in the brain.

Somatic mitochondrial DNA mutations in different grades of glioma.

Aim: Mitochondrial DNA (mtDNA) alterations play an important role in the multistep processes of cancer development. Gliomas are among the most diagnosed brain cancer. The relationship between mtDNA alterations and different grades of gliomas are still elusive. This study aimed to elucidate the profile of somatic mtDNA mutations in different grades of gliomas and correlate it with clinical phenotype. Materials & methods: Forty histopathologically confirmed glioma tissue samples and their matched blood were collected and subjected for mtDNA sequencing. Results & conclusion: About 75% of the gliomas harbored at least one somatic mutation in the mtDNA gene, and 45% of these mutations were pathogenic. Mutations were scattered across the mtDNA genome, and the commonest nonsynonymous mutations were located at complex I and IV of the mitochondrial respiratory chain. These findings may have implication for future research to determine the mitochondrial energetics and its downstream metabolomics on gliomas.

The interweaving relationship between extracellular vesicles and T cells in cancer.

The interdependency between cancer cells and immune cells is an important link in understanding cancer pathogenesis. T cells are important immune cells that are able to either impede or promote tumor growth. Extracellular vesicles or EVs are membrane-encapsulated vesicles that are released by both cancer and immune cells that can act as communicators. Studies have shown that tumor-derived EVs can interact with immune cells, particularly T cells. Vice versa, T cells-derived EVs have also been shown to possess immunomodulatory roles. Therefore, the purpose of this mini-review is to understand the role of tumor-derived EVs and T-cells derived EVs on cancer immunosuppression especially the interweaving role of different types of EVs and how it affects tumor immunity. We also discuss the role of EVs in different types of T cells namely CD8+, CD4+ Th17 and Treg cells. More importantly, we include the limitations and future directions involving this type of research. This will further elucidate our understanding of the important functions of these tiny mediators.

Whole genome sequencing of Malaysian colorectal cancer patients reveals specific druggable somatic mutations.

The incidences of colorectal cancer (CRC) are continuously increasing in some areas of the world, including Malaysia. In this study, we aimed to characterize the landscape of somatic mutations using the whole-genome sequencing approach and identify druggable somatic mutations specific to Malaysian patients. Whole-genome sequencing was performed on the genomic DNA obtained from 50 Malaysian CRC patients' tissues. We discovered the top significantly mutated genes were APC, TP53, KRAS, TCF7L2 and ACVR2A. Four novel, non-synonymous variants were identified in three genes, which were KDM4E, MUC16 and POTED. At least one druggable somatic alteration was identified in 88% of our patients. Among them were two frameshift mutations in RNF43 (G156fs and P192fs) predicted to have responsive effects against the Wnt pathway inhibitor. We found that the exogenous expression of this RNF43 mutation in CRC cells resulted in increased cell proliferation and sensitivity against LGK974 drug treatment and G1 cell cycle arrest. In conclusion, this study uncovered our local CRC patients' genomic landscape and druggable alterations. It also highlighted the role of specific RNF43 frameshift mutations, which unveil the potential of an alternative treatment targeting the Wnt/ß-Catenin signalling pathway and could be beneficial, especially to Malaysian CRC patients.

Regulation of signal transduction pathways in colorectal cancer: implications for therapeutic resistance.

Resistance to anti-cancer treatments is a critical and widespread health issue that has brought serious impacts on lives, the economy and public policies. Mounting research has suggested that a selected spectrum of patients with advanced colorectal cancer (CRC) tend to respond poorly to both chemotherapeutic and targeted therapeutic regimens. Drug resistance in tumours can occur in an intrinsic or acquired manner, rendering cancer cells insensitive to the treatment of anti-cancer therapies. Multiple factors have been associated with drug resistance. The most well-established factors are the emergence of cancer stem cell-like properties and overexpression of ABC transporters that mediate drug efflux. Besides, there is emerging evidence that signalling pathways that modulate cell survival and drug metabolism play major roles in the maintenance of multidrug resistance in CRC. This article reviews drug resistance in CRC as a result of alterations in the MAPK, PI3K/PKB, Wnt/ß-catenin and Notch pathways.

Liquid Biopsy-Based Colorectal Cancer Screening via Surface Markers of Circulating Tumor Cells.

Colorectal cancer (CRC) is ranked second for cancer-related deaths worldwide with approximately half of the patients being diagnosed at the late stages. The untimely detection of CRC results in advancement to the metastatic stage and nearly 90% of cancer-related deaths. The early detection of CRC is crucial to decrease its overall incidence and mortality rates. The recent introduction of circulating tumor cells (CTCs) has enabled a less invasive sampling method from liquid biopsies, besides revealing key information toward CRC metastasis. The current gold standard for CTC identification is the CellSearch® system (Veridex). This first-generation instrumentation relies on a single cell surface marker (CSM) to capture and count CTCs. Detection of CTCs allows the identification of patients at risk for metastasis, whereas CTC enumeration could improve risk assessment, monitoring of systemic therapy, and detection of therapy resistance in advanced metastatic CRC. In this review, we compared the pros and cons between single CSM-based CTC enrichment techniques and multi-marker-based systems. We also highlighted the challenges faced in the routine implementation of CSM-dependent CTC detection methods in CRC screening, prediction, prognosis, disease monitoring, and therapy selection toward precision medicine, as well as the dwelling on post-CTC analysis and characterization methods.

Extracellular Vesicles and DAMPs in Cancer: A Mini-Review.

Certain cancer therapy has been shown to induce immunogenic cell death in cancer cells and may promote tumor progression instead. The external stress or stimuli may induce cell death and contribute toward the secretion of pro inflammatory molecules. The release of damage-associated molecular patterns (DAMPs) upon induction of therapy or cell death has been shown to induce an inflammatory response. Nevertheless, the mechanism as to how the DAMPs are released and engage in such activity needs further in-depth investigation. Interestingly, some studies have shown that DAMPs can be released through extracellular vesicles (EVs) and can bind to receptors such as toll-like receptors (TCRs). Ample pre-clinical studies have shown that cancer-derived EVs are able to modulate immune responses within the tumor microenvironment. However, the information on the presence of such DAMPs within EVs is still elusive. Therefore, this mini-review attempts to summarize and appraise studies that have shown the presence of DAMPs within cancer-EVs and how it affects the downstream cellular process.

HER2/neu-Based Peptide Vaccination-Pulsed with B-Cell Epitope Induced Efficient Prophylactic and Therapeutic Antitumor Activities in TUBO Breast Cancer Mice Model.

Breast cancer is the most common invasive cancer diagnosed among women. A cancer vaccine has been recognized as a form of immunotherapy with a prominent position in the prevention and treatment of breast cancer. The majority of current breast cancer vaccination strategies aim to stimulate antitumor T-cell responses of the HER2/neu oncogene, which is abnormally expressed in breast cancer cells. However, the role of the B-cell humoral response is often underappreciated in the cancer vaccine design. We have advanced this idea by elucidating the role of B-cells in cancer vaccination by designing a chimeric antigenic peptide possessing both cytotoxic T lymphocytes (GP2) and B-cell (P4) peptide epitopes derived from HER2/neu. The chimeric peptide (GP2-P4) was further conjugated to a carrier protein (KLH), forming a KLH-GP2-P4 conjugate. The immunogenicity of KLH-GP2-P4 was compared with KLH-GP2 (lacking the B-cell epitope) in BALB/c mice. Mice immunized with KLH-GP2-P4 elicited more potent antigen-specific neutralizing antibodies against syngeneic TUBO cells (cancer cell line overexpressing HER2/neu) that was governed by a balanced Th1/Th2 polarization in comparison to KLH-GP2. Subsequently, these immune responses led to greater inhibition of tumor growth and longer survival in TUBO tumor-bearing mice in both prophylactic and therapeutic challenge experiments. Overall, our data demonstrated that the B-cell epitope has a profound effect in orchestrating an efficacious antitumor immunity. Thus, a multi-epitope peptide vaccine encompassing cytotoxic T-lymphocytes, T-helper and B-cell epitopes represents a promising strategy in developing cancer vaccines with a preventive and therapeutic modality for the effective management of breast cancer.

Microsatellite Instability in Colorectal Cancer Liquid Biopsy-Current Updates on Its Potential in Non-Invasive Detection, Prognosis and as a Predictive Marker.

Colorectal cancer (CRC) is the third most commonly-diagnosed cancer in the world and ranked second for cancer-related mortality in humans. Microsatellite instability (MSI) is an indicator for Lynch syndrome (LS), an inherited cancer predisposition, and a prognostic marker which predicts the response to immunotherapy. A recent trend in immunotherapy has transformed cancer treatment to provide medical alternatives that have not existed before. It is believed that MSI-high (MSI-H) CRC patients would benefit from immunotherapy due to their increased immune infiltration and higher neo-antigenic loads. MSI testing such as immunohistochemistry (IHC) and PCR MSI assay has historically been a tissue-based procedure that involves the testing of adequate tissue with a high concentration of cancer cells, in addition to the requirement for paired normal tissues. The invasive nature and specific prerequisite of such tests might hinder its application when surgery is not an option or when the tissues are insufficient. The application of next-generation sequencing, which is highly sensitive, in combination with liquid biopsy, therefore, presents an interesting possibility worth exploring. This review aimed to discuss the current body of evidence supporting the potential of liquid biopsy as a tool for MSI testing in CRC.

Nonalcoholic Fatty Liver Disease (NAFLD): Pathogenesis and Noninvasive Diagnosis.

The global prevalence of nonalcoholic fatty liver disease (NAFLD) or metabolic associated fatty liver disease (MAFLD), as it is now known, has gradually increased. NAFLD is a disease with a spectrum of stages ranging from simple fatty liver (steatosis) to a severe form of steatosis, nonalcoholic steatohepatitis (NASH), which could progress to irreversible liver injury (fibrosis) and organ failure, and in some cases hepatocellular carcinoma (HCC). Although a liver biopsy remains the gold standard for accurate detection of this condition, it is unsuitable for clinical screening due to a higher risk of death. There is thus an increased need to find alternative techniques or tools for accurate diagnosis. Early detection for NASH matters for patients because NASH is the marker for severe disease progression. This review summarizes the current noninvasive tools for NAFLD diagnosis and their performance. We also discussed potential and newer alternative tools for diagnosing NAFLD.

Extracellular Vesicles Derived From Colorectal Cancer Affects CD8 T Cells: An Analysis Based on Body Mass Index.

Colorectal cancer (CRC) is one of the most widely diagnosed cancers worldwide. It has been shown that the body-mass index (BMI) of the patients could influence the tumor microenvironment, treatment response, and overall survival rates. Nevertheless, the mechanism on how BMI affects the tumorigenesis process, particularly the tumor microenvironment is still elusive. Herein, we postulate that extracellular vesicles (EVs) from CRC patients and non-CRC volunteers with different BMI could affect immune cells differently, in CD8 T cells particularly. We isolated the EVs from the archived serum of CRC patients with high and low BMI, as well as healthy controls with similar BMI status. The EVs were further characterized via electron microscopy, western blot and dynamic light scattering. Then, functional analysis was performed on CD8 T cells including apoptosis, cell proliferation, gene expression profiling and cytokine release upon co-incubation with the different EVs. Our results suggest that CRC-derived EVs were able to regulate the CD8 T cells. In some assays, low BMI EVs were functionally different than high BMI EVs. This study highlights the possible difference in the regulatory mechanism of cancer patients-derived EVs, especially on CD8 T cells.

Extracellular Vesicles in the Development of the Non-Alcoholic Fatty Liver Disease: An Update.

Non-alcoholic fatty liver disease (NAFLD) is a broad spectrum of liver damage disease from a simple fatty liver (steatosis) to more severe liver conditions such as non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Extracellular vesicles (EVs) are a heterogeneous group of small membrane vesicles released by various cells in normal or diseased conditions. The EVs carry bioactive components in their cargos and can mediate the metabolic changes in recipient cells. In the context of NAFLD, EVs derived from adipocytes are implicated in the development of whole-body insulin resistance (IR), the hepatic IR, and fatty liver (steatosis). Excessive fatty acid accumulation is toxic to the hepatocytes, and this lipotoxicity can induce the release of EVs (hepatocyte-EVs), which can mediate the progression of fibrosis via the activation of nearby macrophages and hepatic stellate cells (HSCs). In this review, we summarized the recent findings of adipocyte- and hepatocyte-EVs on NAFLD disease development and progression. We also discussed previous studies on mesenchymal stem cell (MSC) EVs that have garnered attention due to their effects on preventing liver fibrosis and increasing liver regeneration and proliferation.

L1CAM, CA9, KLK6, HPN, and ALDH1A1 as Potential Serum Markers in Primary and Metastatic Colorectal Cancer Screening.

BACKGROUND: Colorectal cancer (CRC) screening at the earlier stages could effectively decrease CRC-related mortality and incidence; however, accurate screening strategies are still lacking. Considerable interest has been generated in the detection of less invasive tests requiring a small sample volume with the potential to detect several cancer biomarkers simultaneously. Due to this, the ELISA-based method was undertaken in this study. METHODS: Concentrations of neural cell adhesion molecule L1 (L1CAM), carbonic anhydrase IX (CA9), mesothelin (MSLN), midkine (MDK), hepsin (HPN), kallikrein 6 (KLK6), transglutaminase 2 (TGM2) aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), epithelial cell adhesion molecule (EpCAM), and cluster of differentiation 44 (CD44) from blood serum of 36 primary CRC and 24 metastatic CRC (mCRC) were calculated via MAGPIX® System (Luminex Corporation, USA). RESULTS: Significantly increased concentration (p < 0.05) of three serum biomarkers (L1CAM, CA9, and HPN) were shown in mCRC when compared with primary CRC. HPN and KLK6 showed significant differences (p < 0.05) in concentration among different stages of CRC. In contrast, levels of HPN and ALDH1A1 were significantly elevated (p < 0.05) in chemotherapy-treated CRC patients as compared with nontreated ones. Conclusion: Serum biomarkers could act as a potential early CRC diagnostics test, but further additional testings are needed.

The Landscape of Tumor-Specific Antigens in Colorectal Cancer.

Over the last few decades, major efforts in cancer research and treatment have intensified. Apart from standard chemotherapy approaches, immunotherapy has gained substantial traction. Personalized immunotherapy has become an important tool for cancer therapy with the discovery of immune checkpoint inhibitors. Traditionally, tumor-associated antigens are used in immunotherapy-based treatments. Nevertheless, these antigens lack specificity and may have increased toxicity. With the advent of next-generation technologies, the identification of new tumor-specific antigens is becoming more important. In colorectal cancer, several tumor-specific antigens were identified and functionally validated. Multiple clinical trials from vaccine-based and adoptive cell therapy utilizing tumor-specific antigens have commenced. Herein, we will summarize the current landscape of tumor-specific antigens particularly in colorectal cancer.

Antitumor and Anti-Metastatic Effects of Citral-Loaded Nanostructured Lipid Carrier in 4T1-Induced Breast Cancer Mouse Model.

Cancer nano-therapy has been progressing rapidly with the introduction of many novel drug delivery systems. The previous study has reported on the in vitro cytotoxicity of citral-loaded nanostructured lipid carrier (NLC-Citral) on MDA-MB-231 cells and some preliminary in vivo antitumor effects on 4T1 breast cancer cells challenged mice. However, the in vivo apoptosis induction and anti-metastatic effects of NLC-Citral have yet to be reported. In this study, the in vitro cytotoxic, anti-migration, and anti-invasion effects of NLC-Citral were tested on 4T1 breast cancer cells. In addition, the in vivo antitumor effects of oral delivery of NLC-Citral was also evaluated on BALB/c mice induced with 4T1 cells. In vitro cytotoxicity results showed that NLC-Citral and citral gave similar IC50 values on 4T1 cells. However, wound healing, migration, and invasion assays reflected better in vitro anti-metastasis potential for NLC-Citral than citral alone. Results from the in vivo study indicated that both NLC-Citral and citral have anti-tumor and anti-metastasis effects, whereby the NLC-Citral showed better efficacy than citral in all experiments. Also, the delay of tumor progression was through the suppression of the c-myc gene expression and induction of apoptosis in the tumor. In addition, the inhibition of metastasis of 4T1 cells to lung and bone marrow by the NLC-Citral and citral treatments was correlated with the downregulation of metastasis-related genes expression including MMP-9, ICAM, iNOS, and NF-kB and the angiogenesis-related proteins including G-CSF alpha, Eotaxin, bFGF, VEGF, IL-1alpha, and M-CSF in the tumor. Moreover, NLC-Citral showed greater downregulation of MMP-9, iNOS, ICAM, Eotaxin, bFGF, VEGF, and M-CSF than citral treatment in the 4T1-challenged mice, which may contribute to the better anti-metastatic effect of the encapsulated citral. This study suggests that NLC is a potential and effective delivery system for citral to target triple-negative breast cancer.

Integrative meta-analysis for the identification of hub genes in chemoresistant colorectal cancer.

Background: Finding a new target or a new drug to overcome chemoresistance is difficult due to the heterogenous nature of cancer. Meta-analysis was performed to combine the analysis of different microarray studies to get a robust discovery. Materials & methods: Herein, we analyzed three microarray datasets on combination of folinic acid, fluorouracil, and oxaliplatin drugs (FOLFOX) resistance that fit our inclusion/exclusion criteria and performed a meta-analysis using the OmiCC system. Results: We identified several deregulated genes and we discovered HNF4A as a hub gene. We performed functional validation and observed that by targeting HNF4A, HCT116 cells were more sensitive toward both oxaliplatin and 5-fluorouracil significantly. Conclusion: Our findings show that HNF4A could be a potential target in overcoming FOLFOX chemoresistance in colorectal cancer.

Genome-Wide Open Chromatin Methylome Profiles in Colorectal Cancer.

The methylome of open chromatins was investigated in colorectal cancer (CRC) to explore cancer-specific methylation and potential biomarkers. Epigenome-wide methylome of open chromatins was studied in colorectal cancer tissues using the Infinium DNA MethylationEPIC assay. Differentially methylated regions were identified using the ChAMP Bioconductor. Our stringent analysis led to the discovery of 2187 significant differentially methylated open chromatins in CRCs. More hypomethylated probes were observed and the trend was similar across all chromosomes. The majority of hyper- and hypomethylated probes in open chromatin were in chromosome 1. Our unsupervised hierarchical clustering analysis showed that 40 significant differentially methylated open chromatins were able to segregate CRC from normal colonic tissues. Receiver operating characteristic analyses from the top 40 probes revealed several significant, highly discriminative, specific and sensitive probes such as OPLAH cg26256223, EYA4 cg01328892, and CCNA1 cg11513637, among others. OPLAH cg26256223 hypermethylation is associated with reduced gene expression in the CRC. This study reports many open chromatin loci with novel differential methylation statuses, some of which with the potential as candidate markers for diagnostic purposes.