Identification of putative immunologic targets for colon cancer prevention based on conserved gene upregulation from preinvasive to malignant lesions

MiR-3960 inhibits bladder cancer progression via targeting of DEXI

PURPOSE

MicroRNAs (miRNAs) are dominant cargo in exosomes and act as master regulators of cell function, inhibiting mRNA translation and affecting gene silencing. Some aspects of tissue-specific miRNA transport in bladder cancer (BC) and its role in cancer progression are not fully understood.

MATERIALS AND METHODS

A microarray was used to identify miRNAs in mouse bladder carcinoma cell line MB49 exosomes. Real-time reverse transcription polymerase chain reaction was used to examine the expression of miRNAs in BC and healthy donor serum. Western blotting and immunohistochemical staining were used to examine the expression of dexamethasone-induced protein (DEXI) in patients with BC. CRISPR-Cas 9 was used to knock out Dexi in MB49, and flow cytometry was performed to test cell proliferation ability and apoptosis under chemotherapy. Human BC organoid culture, miR-3960 transfection, and 293T-exosome-loaded miR-3960 delivery were used to analyze the effect of miR-3960 on BC progression.

RESULTS

The results showed that miR-3960 levels in BC tissue were positively correlated with patient survival time. Dexi was a major target of miR-3960. Dexi knockout inhibited MB49 cell proliferation and promoted cisplatin- and gemcitabine-induced apoptosis. Transfection of miR-3960 mimic inhibited DEXI expression and organoid growth. In parallel, 293T-exosome-loaded miR-3960 delivery and Dexi knockout significantly inhibited subcutaneous growth of MB49 cells in vivo.

CONCLUSION

Our results demonstrate the potential role of miR-3960-mediated inhibition of DEXI as a therapeutic strategy against BC.

Anti-tumor activity of a T-helper 1 multiantigen vaccine in a murine model of prostate cancer

Prostate cancer is one of the few malignancies that includes vaccination as a treatment modality. Elements of an effective cancer vaccine should include the ability to elicit a Type I T-cell response and target multiple antigenic proteins expressed early in the disease. Using existing gene datasets encompassing normal prostate tissue and tumors with Gleason Score ≤ 6 and ≥ 8, 10 genes were identified that were upregulated and conserved in prostate cancer regardless of the aggressiveness of disease. These genes encoded proteins also expressed in prostatic intraepithelial neoplasia. Putative Class II epitopes derived from these proteins were predicted by a combination of algorithms and, using human peripheral blood, epitopes which selectively elicited IFN-γ or IL-10 dominant antigen specific cytokine secretion were determined. Th1 selective epitopes were identified for eight antigens. Epitopes from three antigens elicited Th1 dominant immunity in mice; PSMA, HPN, and AMACR. Each single antigen vaccine demonstrated significant anti-tumor activity inhibiting growth of implanted Myc-Cap cells after immunization as compared to control. Immunization with the combination of antigens, however, was superior to each alone in controlling tumor growth. When vaccination occurred simultaneously to tumor implant, multiantigen immunized mice had significantly smaller tumors than controls (p = 0.002) and a significantly improved overall survival (p = 0.0006). This multiantigen vaccine shows anti-tumor activity in a murine model of prostate cancer.

Uncovering potential genes in colorectal cancer based on integrated and DNA methylation analysis in the gene expression omnibus database

Background

Colorectal cancer (CRC) is major cancer-related death. The aim of this study was to identify differentially expressed and differentially methylated genes, contributing to explore the molecular mechanism of CRC.

Methods

Firstly, the data of gene transcriptome and genome-wide DNA methylation expression were downloaded from the Gene Expression Omnibus database. Secondly, functional analysis of differentially expressed and differentially methylated genes was performed, followed by protein-protein interaction (PPI) analysis. Thirdly, the Cancer Genome Atlas (TCGA) dataset and in vitro experiment was used to validate the expression of selected differentially expressed and differentially methylated genes. Finally, diagnosis and prognosis analysis of selected differentially expressed and differentially methylated genes was performed.

Results

Up to 1958 differentially expressed (1025 up-regulated and 993 down-regulated) genes and 858 differentially methylated (800 hypermethylated and 58 hypomethylated) genes were identified. Interestingly, some genes, such as GFRA2 and MDFI, were differentially expressed-methylated genes. Purine metabolism (involved IMPDH1), cell adhesion molecules and PI3K-Akt signaling pathway were significantly enriched signaling pathways. GFRA2, FOXQ1, CDH3, CLDN1, SCGN, BEST4, CXCL12, CA7, SHMT2, TRIP13, MDFI and IMPDH1 had a diagnostic value for CRC. In addition, BEST4, SHMT2 and TRIP13 were significantly associated with patients’ survival.

Conclusions

The identified altered genes may be involved in tumorigenesis of CRC. In addition, BEST4, SHMT2 and TRIP13 may be considered as diagnosis and prognostic biomarkers for CRC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09185-0.

Identification of a 3-gene signature for predicting the prognosis of stage II colon cancer based on microsatellite status

Background

Though colon cancer (CC) is one of the most malignant tumors across the world, CC patients with microsatellite instability-high (MSI-H) in stage II seem to have a better prognosis. However, the molecular mechanisms underlying the phenomena haven't been elucidated yet.

Methods

This study enrolled 322 CCs with known microsatellite status from GSE143985, GSE39582 and GSE92921 in the Gene Expression Omnibus (GEO) database. Robust rank aggregation (RRA) analysis, univariate Cox regression analysis and multivariate Cox stepwise regression analysis were performed to identify genes and construct risk score signature. Kaplan-Meier and receiver operating characteristic (ROC) curves analyses were used to evaluate the prognostic value of the signature. The potential mechanisms underlying this signature were assessed in the Metascape database, gene set enrichment analysis (GSEA) and immune infiltration analysis.

Results

RRA analysis identified 40 differently expressed genes (DEGs). A 3-gene risk score signature (MKQ signature) associated with disease-free survival (DFS) was generated. DFS was significantly longer in CC patients with lower than higher scores (P=0.0046). The areas under curves (AUCs) of the time-dependent ROC curves of MKQ signature at 1-, 3- and 5-year DFS were 1, 0.963 and 0.961 respectively. Recurrence-free survival (RFS) was significantly longer in patients in GSE39582 with lower than higher risk scores (P=0.032). The AUCs for 1-, 3- and 5-year RFS in GSE39582 were 0.63, 0.618 and 0.583, respectively, validating the value of the MKQ signature. Functional annotation and GSEA revealed that the MKQ signature was associated with multiple immune-related pathways. Immune cell infiltration was found to differ in patients differing in the MKQ signature.

Conclusions

Gene expression and microsatellite status identified a 3-gene signature (MKQ signature) that could facilitate risk-stratified management in patients with stage II CC. Dysregulation of MSMB, KRT23, and QPRT can serve as prognostic markers in stage II CC.

Breast cancer vaccines for treatment and prevention

Breast cancer is immunogenic and a variety of vaccines have been designed to boost immunity directed against the disease. The components of a breast cancer vaccine, the antigen, the delivery system, and the adjuvant, can have a significant impact on vaccine immunogenicity. There have been numerous immunogenic proteins identified in all subtypes of breast cancer. The majority of these antigens are weakly immunogenic nonmutated tumor-associated proteins. Mutated proteins and neoantigen epitopes are found only in a small minority of patients and are enriched in the triple negative subtype. Several vaccines have advanced to large randomized Phase II or Phase III clinical trials. None of these trials met their primary endpoint of either progression-free or overall survival. Despite these set-backs investigators have learned important lessons regarding the clinical application of breast cancer vaccines from the type of immune response needed for tumor eradication, Type I T-cell immunity, to the patient populations most likely to benefit from vaccination. Many therapeutic breast cancer vaccines are now being tested in combination with other forms of immune therapy or chemotherapy and radiation. Breast cancer vaccines as single agents are now studied in the context of the prevention of relapse or development of disease. Newer approaches are designing vaccines to prevent breast cancer by intercepting high-risk lesions such as ductal carcinoma in situ to limit the progression of these tumors to invasive cancer. There are also several efforts to develop vaccines for the primary prevention of breast cancer by targeting antigens expressed during breast cancer initiation.

Multi-Epitope-Based Vaccines for Colon Cancer Treatment and Prevention

Background

Overexpression of nonmutated proteins involved in oncogenesis is a mechanism by which such proteins become immunogenic. We questioned whether overexpressed colorectal cancer associated proteins found at higher incidence and associated with poor prognosis could be effective vaccine antigens. We explored whether vaccines targeting these proteins could inhibit the development of intestinal tumors in the azoxymethane (AOM)-induced colon model and APC Min mice.

Methods

Humoral immunity was evaluated by ELISA. Web-based algorithms identified putative Class II binding epitopes of the antigens. Peptide and protein specific T-cells were identified from human peripheral blood mononuclear cells using IFN-gamma ELISPOT. Peptides highly homologous between mouse and man were formulated into vaccines and tested for immunogenicity in mice and in vivo tumor challenge. Mice treated with AOM and APC Min transgenic mice were vaccinated and monitored for tumors.

Results

Serum IgG for CDC25B, COX2, RCAS1, and FASCIN1 was significantly elevated in colorectal cancer patient sera compared to volunteers (CDC25B p=0.002, COX-2 p=0.001, FASCIN1 and RCAS1 p<0.0001). Epitopes predicted to bind to human class II MHC were identified for each protein and T-cells specific for both the peptides and corresponding recombinant protein were generated from human lymphocytes validating these proteins as human antigens. Some peptides were highly homologous between mouse and humans and after immunization, mice developed both peptide and protein specific IFN-γ-secreting cell responses to CDC25B, COX2 and RCAS1, but not FASCIN1. FVB/nJ mice immunized with CDC25B or COX2 peptides showed significant inhibition of growth of the syngeneic MC38 tumor compared to control (p<0.0001). RCAS1 peptide vaccination showed no anti-tumor effect. In the prophylactic setting, after immunization with CDC25B or COX2 peptides mice treated with AOM developed significantly fewer tumors as compared to controls (p<0.0002) with 50% of mice remaining tumor free in each antigen group. APC Min mice immunized with CDC25B or COX2 peptides developed fewer small bowel tumors as compared to controls (p=0.01 and p=0.02 respectively).

Conclusions

Immunization with CDC25B and COX2 epitopes consistently suppressed tumor development in each model evaluated. These data lay the foundation for the development of multi-antigen vaccines for the treatment and prevention of colorectal cancer.

Meeting Report: Translational Advances in Cancer Prevention Agent Development Meeting

The Division of Cancer Prevention of the National Cancer Institute (NCI) and the Office of Disease Prevention of the National Institutes of Health co-sponsored the Translational Advances in Cancer Prevention Agent Development Meeting on August 27 to 28, 2020. The goals of this meeting were to foster the exchange of ideas and stimulate new collaborative interactions among leading cancer prevention researchers from basic and clinical research; highlight new and emerging trends in immunoprevention and chemoprevention as well as new information from clinical trials; and provide information to the extramural research community on the significant resources available from the NCI to promote prevention agent development and rapid translation to clinical trials. The meeting included two plenary talks and five sessions covering the range from pre-clinical studies with chemo/immunopreventive agents to ongoing cancer prevention clinical trials. In addition, two NCI informational sessions describing contract resources for the preclinical agent development and cooperative grants for the Cancer Prevention Clinical Trials Network were also presented.

Novel Protein-Based Vaccine against Self-Antigen Reduces the Formation of Sporadic Colon Adenomas in Mice

Simple Summary

Colorectal cancer remains a leading cause of cancer-related mortality worldwide. However, high-risk populations with a genetic predisposition for colorectal cancer could benefit greatly from novel and efficacious immunopreventive strategies that afford long-lasting protection. The achaete-scute family bHLH transcription factor 2 (Ascl2) has been identified as a promising target for immunoprevention of colorectal cancer, based on its induction during the formation and progression of colorectal tumors and its minimal expression observed in healthy tissue. The goal of the present study was to determine the efficacy of a protein-based vaccine targeting Ascl2 in combination with an anti-PD-1 treatment in a spontaneous colorectal cancer mouse model. This novel vaccine strategy promotes potent tumor-specific immunity, and prevents the formation of colon adenomas in mice. The results demonstrate that Ascl2 is a promising target for immunoprevention for individuals at elevated risk of developing colorectal cancer.

Abstract

Novel immunopreventive strategies are emerging that show great promise for conferring long-term protection to individuals at high risk of developing colorectal cancer. The KISIMA vaccine platform utilizes a chimeric protein comprising: (1) a selected tumor antigen; (2) a cell-penetrating peptide to improve antigen delivery and epitope presentation, and (3) a TLR2/4 agonist to serve as a self-adjuvant. This study examines the ability of a KISIMA vaccine against achaete-scute family bHLH transcription factor 2 (Ascl2), an early colon cancer antigen, to reduce colon tumor formation by stimulating an anti-tumor immune response. Vaccine administrations were well-tolerated and led to circulating antibodies and antigen-specific T cells in a mouse model of colorectal cancer. To assess preventive efficacy, the vaccine was administered to mice either alone or in combination with the immune checkpoint inhibitor anti-PD-1. When delivered to animals prior to colon tumor formation, the combination strategy significantly reduced the development of colon microadenomas and adenomas, as compared to vehicle-treated controls. This response was accompanied by an increase in the intraepithelial density of CD3+ T lymphocytes. Together, these data indicate that the KISIMA-Ascl2 vaccine shows great potential to be a safe and potent immunopreventive intervention for individuals at high risk of developing colorectal cancer.

Colorectal cancer prevention: Immune modulation taking the stage

Prevention or early detection is one of the most promising strategies against colorectal cancer (CRC), the second leading cause of cancer death in the US. Recent studies indicate that antitumor immunity plays a key role in CRC prevention. Accumulating evidence suggests that immunosurveillance represents a critical barrier that emerging tumor cells have to overcome in order to sustain the course of tumor development. Virtually all of the agents with cancer preventive activity have been shown to have an immune modulating effect. A number of immunoprevention studies aimed at triggering antitumor immune response against early lesions have been performed, some of which have shown promising results. Furthermore, the recent success of immune checkpoint blockade therapy reinforces the notion that cancers including CRC can be effectively intervened via immune modulation including immune normalization, and has stimulated various immune-based combination prevention studies. This review summarizes recent advances to help better harness the immune system in CRC prevention.

Over-expression of AURKA, SKA3 and DSN1 contributes to colorectal adenoma to carcinoma progression

Development of colorectal cancer (CRC) involves sequential transformation of normal mucosal tissues into benign adenomas and then adenomas into malignant tumors. The identification of genes crucial for malignant transformation in colorectal adenomas (CRAs) has been based primarily on cross-sectional observations. In this study, we identified relevant genes using autologous samples. By performing genome-wide SNP genotyping and RNA sequencing analysis of adenocarcinomas, adenomatous polyps, and non-neoplastic colon tissues (referred as tri-part samples) from individual patients, we identified 68 genes with differential copy number alterations and progressively dysregulated expression. Aurora A, SKA3, and DSN1 protein levels were sequentially up-regulated in the samples, and this overexpression was associated with chromosome instability (CIN). Knockdown of SKA3 in CRC cells dramatically reduced cell growth rates and increased apoptosis. Depletion of SKA3 or DSN1 induced G2/M arrest and decreased migration, invasion, and anchorage-independent growth. AURKA and DSN1 are thus critical for chromosome 20q amplification-associated malignant transformation in CRA. Moreover, SKA3 at chromosome 13q was identified as a novel gene involved in promoting malignant transformation. Evaluating the expression of these genes may help identify patients with progressive adenomas, helping to improve treatment.

The dawn of vaccines for cancer prevention

An important role of the immune system is in the surveillance for abnormal or transformed cells, which is known as cancer immunosurveillance. Through this process, the first changes to normal tissue homeostasis caused by infectious or other inflammatory insults can be detected by the immune system through the recognition of antigenic molecules (including tumour antigens) expressed by abnormal cells. However, as they develop, tumour cells can acquire antigenic and other changes that allow them to escape elimination by the immune system. To bias this process towards elimination, immunosurveillance can be improved by the administration of vaccines based on tumour antigens. Therapeutic cancer vaccines have been extensively tested in patients with advanced cancer but have had little clinical success, which has been attributed to the immunosuppressive tumour microenvironment. Thus, the administration of preventive vaccines at pre-malignant stages of the disease holds promise, as they function before tumour-associated immune suppression is established. Accordingly, immunological and clinical studies are yielding impressive results.

Expression of Wnt-signaling pathway genes and their associations with miRNAs in colorectal cancer

The Wnt-signaling pathway functions in regulating cell growth and thus is involved in the carcinogenic process of several cancers, including colorectal cancer. We tested the hypothesis that multiple genes in this signaling pathway are dysregulated and that miRNAs are associated with these dysregulated genes. We used data from 217 colorectal cancer (CRC) cases to evaluate differences in Wnt-signaling pathway gene expression between paired CRC and normal mucosa and identify miRNAs that are associated with these genes. Gene expression data from RNA-Seq and miRNA expression data from Agilent Human miRNA Microarray V19.0 were analyzed. We focused on genes most strongly associated with CRC (fold change (FC) of >1.5 or <0.67) and that were statistically significant after adjustment for multiple comparisons. Of the 138 Wnt-signaling pathway genes examined, 27 were significantly down-regulated (FC<0.67) and 32 genes were significantly up-regulated (FC>1.50) after adjusting for multiple comparisons. Thirteen of the 66 Wnt-signaling genes that were differentially expressed in CRC tumors were associated with differential expression of miRNAs. A total of 93 miRNA:mRNA associations were detected for these 13 genes. Of these 93 associations, 36 miRNA seed-region matches were observed, suggesting that miRNAs have both direct and indirect effects on Wnt-signaling pathway genes. In summary, our data supports the hypothesis that the Wnt-signaling pathway is dysregulated in CRC and suggest that miRNAs may importantly influence that dysregulation.

Biomarkers in Tumorigenesis Using Cancer Cell Lines: A Systematic Review

Cancer is a leading cause of death worldwide. Despite many research advancements in the field, the genetic changes regulating the transformation of normal oral cells into malignant cells have not been fully elucidated. Several studies have evaluated carcinogenesis at the molecular level. Cancer cell lines are commonly used in biomedical research because they provide an unlimited source of cells and represent various stages of initiation and progression of carcinogenesis in vitro. Aims: The objective of the study was to review original research articles using cancer cell lines as a tool to understand carcinogenesis and to identify the genes involved in tumor development. Additionally, we also examined the application of the genes as predictive biomarkers. Methods and Materials: Several databases, including PubMed, Google Scholar, Ebsco, and Science Direct, were searched from 1985 to December 2016 using various combinations of the following key words: “mouth neoplasm”, “cell lines”, and “tumorigenesis”. Original experimental studies published in English were included. We excluded letters to the editor, historic reviews, and unpublished data from the analysis. Results: There were 17 studies (in vitro) included in the analysis. There were 14 genes and 4 miRNAs involved in malignant transformation of oral keratinocytes into cancer cells. The most commonly studied genes were p53, cyclin D1, and hTERT. Conclusion: Additional reviews and studies are needed to identify a panel of genes specific to various potentially malignant disorders and to aid in the early detection of oral squamous cell carcinoma (OSCC) because tumorigenesis involves the mutation of multiple genes. Furthermore, improving advanced cost-effective diagnostic methods may benefit the public health sector.

Meta-analysis of possible role of cadherin gene methylation in evolution and prognosis of hepatocellular carcinoma with a PRISMA guideline

BACKGROUND

Cadherins (CDHs) have been reported to be associated with cancer. However, the clinical significance of CDH gene methylation in hepatocellular carcinoma (HCC) remains unclear.

METHODS

Based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement criteria, available studies were identified from online electronic database. The overall odds ratio (OR) and the corresponding 95% confidence interval (95% CI) were calculated and analyzed.

RESULTS

A total of 29 eligible studies with 2562 HCC samples and 1685 controls were included. E-cadherin (CDH1) hypermethylation was observed to be significantly higher in HCC than in benign, adjacent, or normal samples. Moreover, CDH1 hypermethylation was not associated with gender, tumor grade, clinical stage, hepatitis B virus (HBV), or hepatitis C virus (HCV) infection in HCC patients. H-cadherin (CDH13), protocadherin-10 (PCDH10), P-cadherin (CDH3), and M-cadherin (CDH15) methylation may have an increased risk of HCC in fewer than 4 studies, and methylated cadherin 8, type 2 (CDH8) and OB-cadherin (CDH11) had a similar OR in HCC and adjacent samples. When HCC samples were compared with normal samples, the analysis of sample type revealed a significantly higher OR in normal blood samples than in normal tissues for hypermethylated CDH1 (50.82 vs 4.44).

CONCLUSION

CDH1 hypermethylation may play a key role in the carcinogenesis of HCC. However, CDH1 hypermethylation was not correlated with clinicopathological features. Methylated CDH13, PCDH10, CDH3, and CDH15, but not methylated CDH8 or CDH11, may lead to an increased risk of HCC. Hypermethylated CDH1 may become a noninvasive blood biomarker. Further studies with more data are necessary.

Current modalities in cancer immunotherapy: Immunomodulatory antibodies, CARs and vaccines

Successes of immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cell therapy in curing patients with otherwise lethal cancers have validated immunotherapy as a treatment for cancer and have inspired excitement for its broader potential. Most promising is the ability of each approach to eliminate bulky and advanced-stage cancers and to achieve durable cures. Despite this success, to date only a subset of cancer patients and a limited number of cancer types respond to these therapies. A major goal now is to expand the types of cancer and number of patients who can be successfully treated. To this end a multitude of immunotherapies are being tested clinically in new combinations, and many new immunomodulatory antibodies and CARs are in development. A third major immunotherapeutic approach with renewed interest is cancer vaccines. While over 20years of therapeutic cancer vaccine trials have met with limited success, these studies have laid the groundwork for the use of therapeutic vaccines in combination with other immunotherapies or alone as prophylactic cancer vaccines. Prophylactic vaccines are now poised to revolutionize cancer prevention as they have done for the prevention of infectious diseases. In this review we examine three major cancer immunotherapy modalities: immunomodulatory antibodies, CAR T cell therapy and vaccines. For each we describe the current state of the art and outline major challenges and research directions forward.

Transforming Cancer Prevention through Precision Medicine and Immune-oncology

We have entered a transformative period in cancer prevention (including early detection). Remarkable progress in precision medicine and immune-oncology, driven by extraordinary recent advances in genome-wide sequencing, big-data analytics, blood-based technologies, and deep understanding of the tumor immune microenvironment (TME), has provided unprecedented possibilities to study the biology of premalignancy. The pace of research and discovery in precision medicine and immunoprevention has been astonishing and includes the following clinical firsts reported in 2015: driver mutations detected in circulating cell-free DNA in patients with premalignant lesions (lung); clonal hematopoiesis shown to be a premalignant state; molecular selection in chemoprevention randomized controlled trial (RCT; oral); striking efficacy in RCT of combination chemoprevention targeting signaling pathway alterations mechanistically linked to germline mutation (duodenum); molecular markers for early detection validated for lung cancer and showing promise for pancreatic, liver, and ovarian cancer. Identification of HPV as the essential cause of a major global cancer burden, including HPV16 as the single driver of an epidemic of oropharyngeal cancer in men, provides unique opportunities for the dissemination and implementation of public health interventions. Important to immunoprevention beyond viral vaccines, genetic drivers of premalignant progression were associated with increasing immunosuppressive TME; and Kras vaccine efficacy in pancreas genetically engineered mouse (GEM) model required an inhibitory adjuvant (Treg depletion). In addition to developing new (e.g., epigenetic) TME regulators, recent mechanistic studies of repurposed drugs (aspirin, metformin, and tamoxifen) have identified potent immune activity. Just as precision medicine and immune-oncology are revolutionizing cancer therapy, these approaches are transforming cancer prevention. Here, we set out a brief agenda for the immediate future of cancer prevention research (including a "Pre-Cancer Genome Atlas" or "PCGA"), which will involve the inter-related fields of precision medicine and immunoprevention - pivotal elements of a broader domain of personalized public health.

Cancer immunoprevention

Cancer immunotherapy is now a reality. The results are phenomenal but the cost is outrageous. Even if the cost eventually comes down and immunotherapy becomes more broadly available, using the knowledge derived from immunotherapy to apply to immunoprevention would be a good strategy. The most likely approach to cancer immunoprevention is cancer vaccines. To date, cancer vaccines have been tested mostly in the setting of advanced disease. Numerous immunosuppressive mechanisms have been identified in the tumor microenvironment as well as systemically that compromise the ability of cancer patients to respond to the vaccines. Multiple approaches are being tested to improve therapeutic cancer vaccine efficacy, including combinations with other immunotherapies. An alternative approach is to administer the vaccines to individuals without cancer but at high risk for cancer. Data in support of this approach and immunoprevention in general is accumulating and clinical testing has started.

Gene-expression analysis of a colorectal cancer-specific discriminatory transcript set on formalin-fixed, paraffin-embedded (FFPE) tissue samples

BACKGROUND

A recently published transcript set is suitable for gene expression-based discrimination of normal colonic and colorectal cancer (CRC) biopsy samples. Our aim was to test the discriminatory power of the CRC-specific transcript set on independent biopsies and on formalin-fixed, paraffin-embedded (FFPE) tissue samples.

METHODS

Total RNA isolations were performed with the automated MagNA Pure 96 Cellular RNA Large Volume Kit (Roche) from fresh frozen biopsies stored in RNALater (CRC (n = 15) and healthy colonic (n = 15)), furthermore from FFPE specimens including CRC (n = 15) and normal adjacent tissue (NAT) (n = 15) specimens next to the tumor. After quality and quantity measurements, gene expression analysis of a colorectal cancer-specific marker set with 11 genes (CA7, COL12A1, CXCL1, CXCL2, CHI3L1, GREM1, IL1B, IL1RN, IL8, MMP3, SLC5A7) was performed with array real-time PCR using Transcriptor First Strand cDNA Synthesis Kit (Roche) and RealTime ready assays on LightCycler480 System (Roche). In situ hybridization for two selected transcripts (CA7, CXCL1) was performed on NAT (n = 3), adenoma (n = 3) and CRC (n = 3) FFPE samples.

RESULTS

Although analytical parameters of automatically isolated RNA samples showed differences between fresh frozen biopsy and FFPE samples, both quantity and the quality enabled their application in gene expression analyses. CRC and normal fresh frozen biopsy samples could be distinguished with 93.3% sensitivity and 86.7% specificity and FFPE samples with 96.7 and 70.0%, respectively. In situ hybridization could confirm the upregulation of CXCL1 and downregulation of CA7 in colorectal adenomas and tumors compared to healthy controls.

CONCLUSION

According to our results, gene expression analysis of the analyzed colorectal cancer-specific marker set can also be performed from FFPE tissue material. With the addition of an automated workflow, this marker set may enhance the objective classification of colorectal neoplasias in the routine procedure in the future.

Cancer immunoprevention--the next frontier

Cancer immunotherapy is a rapidly developing field, but limited in its success by a high tumor burden and immune tolerance. In contrast, immunoprevention has the potential to prevent cancer before the development of immune tolerance, and to prevent cancer recurrence in the setting of minimal residual disease. Although immunoprevention for viral-induced cancers has been successful in the setting of hepatitis B and human papillomavirus vaccination, primary prevention of nonviral-induced cancers is in its infancy. In contrast, prevention of cancer recurrence after adjuvant treatment (secondary prevention) is gaining steam. This review provides an overview of the scope of research in cancer immunoprevention over the last three years and directions for future research.

MiR-3960 binding sites with mRNA of human genes

The importance of miRNA in cellular regulation is gaining momentum. Therefore, it is of interest to study miRNA in human genes. Hence, the humanmRNA sequences (12,175) were searched for miRNA binding sites and 2,563predicted sites were found. We observed that the miR-3960 has more than 1000mRNA binding sites with high affinity (with ΔG/ΔGm values greater than or equal to 90%) for 375genes. The miR-3960 has 565 binding sites in the 5'UTRs and 515 sites in theCDS of mRNAs. Nucleotide sequences of the binding sites in CDS encode for polyalanine orpolyproline. It is observed that miR-3960 has binding sites in 73 mRNAs of target genesencoded transcription factors. Thus, we document predictedproperties (polysites, sites in CDS) of uncharacterized miR-3960 binding sites. The studying of the miRNA properties is important for creation of diagnostic methods of cancer.