Search Results (7)

Aberrant glycosylation plays a crucial role in tumour progression and invasiveness. Tumour-associated carbohydrate antigens (TACAs) represent a valuable set of targets for immunotherapeutic approaches. The poor immunogenicity of glycan structures, however, requires a more effective and well-directed way of targeting TACAs on the surface of cancer cells than antibodies. The glycosphingolipid globotriaosylceramide (Gb3) is a well-established TACA present in a multitude of cancer types. Its overexpression has been linked to metastasis, invasiveness, and multidrug resistance. In the present study, we propose to use a dimeric fragment of the Shiga toxin B-subunit (StxB) to selectively target Gb3-positive cancer cells in a StxB-scFv UCHT1 lectibody. The lectibody, comprised of a lectin and the UCHT1 antibody fragment, was produced in E. coli and purified via Ni-NTA affinity chromatography. Specificity of the lectibody towards Gb3-positive cancer cell lines and specificity towards the CD3 receptor on T cells, was assessed using flow cytometry. We evaluated the efficacy of the lectibody in redirecting T cell cytotoxicity towards Gb3-overexpressing cancer cells in luciferase-based cytotoxicity in vitro assays. The StxB-scFv UCHT1 lectibody has proven specific for Gb3 and could induce the killing of up to 80% of Gb3-overexpressing cancer cells in haemorrhagic and solid tumours. The lectibody developed in this study, therefore, highlights the potential that lectibodies and lectins in general have for usage in immunotherapeutic approaches to boost the efficacy of established cancer treatments. Full article

Modulation of the immune system has been demonstrated as a powerful approach to treating cancer. Immunotherapies are generally classified as active or passive according to their ability to trigger the immune system. During the last decades, information regarding the relevance of aberrant glycosylation as a major player in tumour biology encouraged expectations for the development of new therapeutic strategies directed at glycans. Several tumour-associated carbohydrate antigens (TACAs) have been identified and validated as suitable immunotherapeutic targets, leading to promising therapeutic developments. It is known that TACAs are poorly immunogenic since they are unable to trigger a proper immune response. Given that they are not presented by major histocompatibility complex (MHC) molecules and that they induce immune tolerance, the development of active immunotherapeutic strategies against TACAs is a real challenge. However, antitumor strategies based on mimetics of TACAs have been developed and show promising results. Active immunotherapies based on TACAs mimicry can currently be grouped into strategies based on the use of mimetic peptides and anti-idiotype (Id) antibodies. In this review, we discussed the scientific basis on which these strategies are based and the available therapeutic options that have shown the best results in preclinical studies and in clinical practice. Full article

Pancreatic cancer is one of the deadliest tumours worldwide, and its poor prognosis is due to an inability to detect the disease at the early stages, thereby creating an urgent need to develop non-invasive biomarkers. P-element–induced wimpy testis (PIWI) proteins work together with piwi-interacting RNAs (piRNAs) to perform epigenetic regulation and as such hold great potential as biomarkers for pancreatic cancer. PIWIL2 and PIWIL4 are associated with better prognosis, while PIWIL1 and PIWIL3 involvement appears to be associated with carcinogenesis. We aimed to discover PIWIL3- and PIWIL4-modulated piRNAs and determine their potential mechanisms in pancreatic cancer and the clinical implications. PIWIL3 or PIWIL4 was downregulated in pancreatic cancer-derived cell lines or in a non-tumour cell line. Differentially expressed piRNAs were analysed by next generation sequencing of small RNA. Nine fresh-frozen samples from solid human pancreases (three healthy pancreases, three intraductal papillary mucinous neoplasms, and three early-stage pancreatic cancers) were included in the sequencing analysis. Two piRNAs associated with PIWIL3 (piR-168112 and piR-162725) were identified in the neoplastic cells; in untransformed samples, we identified one piRNA associated with PIWIL4 (pir-366845). After validation in pancreatic cancer-derived cell lines and one untransformed pancreatic cell line, these piRNAs were evaluated in plasma samples from healthy donors (n = 27) or patients with pancreatic cancer (n = 45). Interestingly, piR-162725 expression identified pancreatic cancer patients versus healthy donors in liquid biopsies. Moreover, the potential of the serum carbohydrate antigen 19-9 (CA19-9) biomarker to identify pancreatic cancer patients was greatly enhanced when combined with piR-162725 detection. The enhanced diagnostic potential for the early detection of pancreatic cancer in liquid biopsies of these new small non-coding RNAs will likely improve the prognosis and management of this deadly cancer. Full article

Pancreatic cancer has one of the highest cancer mortality rates, as it is often detected in late stages, when unresectable tumours are present. Researchers have identified a biomarker associated with the early detection of pancreatic cancer, called Carbohydrate Antigen 19-9 (CA19-9)—researchers have recommended it for pancreatic cancer screening, and for the monitoring of the efficacy of pancreatic cancer treatments. The development of a biosensor for the detection of CA19-9 is discussed in this paper. The biosensor uses capacitive spectroscopy on gold interdigitated electrodes. This electrochemical transducer mechanism was selected as appropriate due to its increased popularity in point-of-care applications. Mouse monoclonal anti-CA19-9 antibodies were covalently bound to the gold surface using cysteamine hydrochloride and glutaraldehyde, and immobilization was verified with a Zeiss AxioObserver fluorescence microscope. Next, the antigen was prepared in different concentrations, and added to the prepared electrodes. Impedance spectroscopy was carried out using the PalmSens4 Electrochemical Interface, where five different concentrations of CA19-9 were detected in this process. The concentrations ranged from 10 U/mL to 300 U/mL, which includes the threshold concentration of CA19-9 for the detection of pancreatic cancer, of 37 U/mL. This biosensor is, therefore, suited to detect the CA19-9 concentrations needed for pancreatic cancer screening. Full article

Aberrant glycosylation in tumour progression is currently a topic of main interest. Tumour-associated carbohydrate antigens (TACAs) are expressed in a wide variety of epithelial cancers, being both a diagnostic tool and a potential treatment target, as they have impact on patient outcome and disease progression. Glycans affect both tumour-cell biology properties as well as the antitumor immune response. It has been ascertained that TACAs affect cell migration, invasion and metastatic properties both when expressed by cancer cells or by their extracellular vesicles. On the other hand, tumour-associated glycans recognized by C-type lectin receptors in immune cells possess immunomodulatory properties which enable tumour growth and immune response evasion. Yet, much remains unknown, concerning mechanisms involved in deregulation of glycan synthesis and how this affects cell biology on a major level. This review summarises the main findings to date concerning how aberrant glycans influence tumour growth and immunity, their application in cancer treatment and spotlights of unanswered challenges remaining to be solved. Full article

Telomerase reactivation during hepatocarcinogenesis is recurrently caused by two point mutations occurring most frequently at the nucleotide −124 (95%) and occasionally at the nucleotide −146 (<5%) upstream of the TERT translational start site in hepatocellular carcinoma (HCC). In this study, we designed a droplet digital PCR (ddPCR) assay to detect TERT promoter (TERTp) nucleotide change G>A at position −124 and to quantify the mutant allele frequency (MAF) in 121 primary liver cancers, including 114 HCC along with 23 autologous cirrhotic tissues, five cholangiocarcinoma (CC), and two hepato-cholangiocarcinoma (HCC-CC). All cases were evaluated for tumour markers such as α-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), and carcinoembryonic antigen (CEA). We compared the sensitivity of ddPCR and Sanger sequencing and investigated the prognostic relevance of TERTp mutations. The TERTp G>A transition was identified in 63.6% and 52.1% of HCC samples by ddPCR and Sanger sequencing, respectively. One out of 23 (4.3%) peri-tumour tissues tested positive only by ddPCR. One out of five CC (20%) and none of the HCC-CC were found concordantly mutated by the two methods. The TERTp MAF ranged from 2% to 66%, and the large majority (85.5%) of mutated samples showed a value above 20%. A statistically significant correlation was found between TERTp mutation and tumour size (p = 0.048), while an inverse correlation was observed with CA19-9 levels (p = 0.0105). Moreover, HCC patients with TERTp −124A had reduced survival. In conclusion, the single nucleotide variation G>A at position −124 in TERTp, detected either by ddPCR or by Sanger sequencing, showed a remarkable high frequency in HCC. Such mutation is associated with lower levels of CA19-9 and reduced survival in HCC patients suggesting that the TERTp status may represent a distinct signature of liver cancer subgroups. Full article

SRL is a cell wall associated developmental-stage specific lectin secreted by Sclerotium rolfsii, a soil-born pathogenic fungus. SRL displays specificity for TF antigen (Galβ1→3GalNAc-α-Ser//Thr) expressed in all cancer types and has tumour suppressing effects in vivo. Considering the immense potential of SRL in cancer research, we have generated two variant gene constructs of SRL and expressed in E. coli to refine the sugar specificity and solubility by altering the surface charge. SSR1 and SSR2 are two different recombinant variants of SRL, both of which recognize TF antigen but only SSR1 binds to Tn antigen (GalNAcα-Ser/Thr). The glycan array analysis of the variants demonstrated that SSR1 recognizes TF antigen and their derivative with high affinity similar to SRL but showed highest affinity towards the sialylated Tn antigen, unlike SRL. The carbohydrate binding property of SSR2 remains unaltered compared to SRL. The crystal structures of the two variants were determined in free form and in complex with N-acetylglucosamine at 1.7 Å and 1.6 Å resolution, respectively. Structural analysis highlighted the structural basis of the fine carbohydrate specificity of the two SRL variants and results are in agreement with glycan array analysis. Full article