Signatures of anti-Thomsen — friedenreich antigen antibody diversity in colon cancer patients

Aim: To determine whether the structural and functional diversities of naturally occurring antibodies to the Thomsen — Friedenreich (TF) antigen may be of diagnostic and prognostic value in colon cancer. Materials and Methods: Serum samples were taken from patients with colon cancer (n = 94) and healthy controls (n = 64). The level of TF-specific antibody isotypes and their sialylation were determined using ELISA and lectin-ELISA with synthetic TF-polyacrylamide conjugate as an antigen and a sialic acid-specific Sambucus nigra agglutinin (SNA). The avidity was determined using ammonium thiocyanate as a chaotrope. The accuracy of diagnostics was evaluated using the receiver operator characteristic curve analysis and the survival analysis employing the Kaplan — Meier method. Results: Compared to healthy controls, patients with colon cancer exhibited a lower level of anti-TF IgG antibodies, significantly lower ratios of TF-specific IgG/IgM and IgG/IgA, an increased SNA reactivity of anti-TF antibodies, mostly on account of IgG, and a lower avidity of TF-specific antibodies, especially their SNA-reactive subset. An increased SNA reactivity of anti-TF IgG was observed already at the early stages of cancer (p = 0.0004). The decrease of the ratio of IgG/IgM and IgG/IgA showed a good accuracy of diagnostics with about 60% sensitivity at 90% specificity. A similar potential was found for the SNA binding/IgG level index. The high level of TF-specific IgA antibodies was associated with a lower survival rate (hazard ratio = 0.34). Conclusion: This is the first report ever on the colon cancer-related signatures of anti-TF antibody diversity which show diagnostic potential, including in early cancer, and prognostic value. The hypersialylation of TF-specific antibodies appeared to be a common phenomenon in cancer. The signatures may be used as non-invasive antibody-based markers for colon cancer

H. pylori Seropositivity before Age 40 and Subsequent Risk of Stomach Cancer: A Glimpse of the True Relationship?

Stomach carcinogenesis involves mucosal and luminal changes that favor spontaneous disappearance of Helicobacter pylori. Therefore, the association between the infection and cancer risk might typically be underestimated. As acquisition of the infection almost invariably occurs before adulthood, the serostatus at age 16–40 should best reflect the lifetime occurrence of the infection. We therefore conducted a case-control study nested within a historic cohort of about 400,000 individuals who donated sera before age 40 to either of two large Swedish Biobanks between 1968 and 2006, and whose records were linked to complete nationwide registers. For each stomach adenocarcinoma case occurring at least 5 years after serum donation 2 controls were selected matched on age, sex and year of donation and biobank. Serum immunoglobulin G antibodies against H. pylori cell-surface antigens (Hp-CSAs) were measured with an enzyme–linked immunosorbent assay and antibodies against CagA with an immunoblot assay. Conditional logistic regression models were used to estimate odds ratios (ORs) for stomach adenocarcinoma among H. pylori infected relative to uninfected. We confirmed 59 incident cases of stomach adenocarcinoma (41 non-cardia tumors) during follow-up. ORs for non-cardia stomach adenocarcinoma among subjects with Hp-CSA antibodies (regardless of CagA serostatus), antibodies against CagA (regardless of Hp-CSA serostatus), and antibodies to both, relative to those who were seronegative to both, were 17.1 (95% confidence interval [CI] 4.0–72.9), 10.9 (95% CI 3.2–36.9), and 48.5 (95% CI 5.8–407.4), respectively. H. pylori infection is a much stronger risk factor for non-cardia stomach adenocarcinoma than initially realized. However, further studies are needed to answer whether it is a necessary cause, as the possibility of misclassification of H. pylori status could not be ruled out in our study

Down-regulation of HSP70 sensitizes gastric epithelial cells to apoptosis and growth retardation triggered by H. pylori

<p>Abstract</p> <p>Background</p> <p><it>H. pylori </it>infection significantly attenuated the expression of HSP70 in gastric mucosal cells. However, the role of HSP70 cancellation in <it>H. pylori</it>-associated cell damages is largely unclear.</p> <p>Methods</p> <p>Small interfering RNA (siRNA) was used to down-regulate HSP70 in gastric epithelial cell lines AGS. The transfected cells were then incubated with <it>H. pylori </it>and the functions of HSP70 suppression were observed by viability assay, cell cycle analyses and TUNEL assay. HSP70 target apoptotic proteins were further identified by Western blot.</p> <p>Results</p> <p>The inhibition of HSP70 has further increased the effect of growth arrest and apoptosis activation triggered by <it>H. pylori </it>in gastric epithelial cells. The anti-proliferation function of HSP70 depletion was at least by up-regulating p21 and cell cycle modulation with S-phase accumulation. An increase of apoptosis-inducing factor (AIF) and cytosolic cytochrome C contributes to the activation of apoptosis following down-regulation of intracellular HSP70. Extracellular HSP70 increased cellular resistance to apoptosis by suppression the release of AIF and cytochrome c from mitochondria, as well as inhibition of p21 expression.</p> <p>Conclusions</p> <p>The inhibition of HSP70 aggravated gastric cellular damages induced by <it>H. pylori</it>. Induction of HSP70 could be a potential therapeutic target for protection gastric mucosa from <it>H. pylori</it>-associated injury.</p