Competition of commensal and probiotic bacteria with pathogens for adhesion and colonization is one of the important protective mechanisms of gastrointestinal tract. In this study, we examined the ability of Lactobacillus paracasei to inhibit the adhesion of pathogenic Salmonella enterica to human colon adenocarcinoma Caco‐2 cells. Caco‐2 cells were grown for 6 or 21 days to obtain nondifferentiated or well‐differentiated cells, respectively. In adhesion experiments, bacteria were added to the cells for 2 or 4 hours. The number of attached bacteria was expressed as colony‐forming units (CFUs), Caco‐2 cells were counted in hematocytometer. Both bacterial strains used adhered better to well‐differentiated than to nondifferentiated Caco‐2 cells, however, the amount of Salmonella adhered to Caco‐2 after 2 hours of contact was 12‐fold higher in comparison to L. paracasei and almost 27‐fold higher after 4 hours of contact. Two types of experiments were done: coincubation (both bacteria were added to Caco‐2 cells simultaneously), and preincubation (L. paracasei was incubated with Caco‐2 cells first, and then S. enterica was added). In coincubation experiment, the presence of L. paracasei decreased S. enterica adhesion by 4‐fold and in preincubation experiment even 7‐fold. Generally, Lactobacillus spent culture supernatants (SCSs) acted weaker as inhibitors of Salmonella adhesion in comparison to the whole L. paracasei culture in coincubation experiment. In conclusion, the displacement of pathogens by lactic acid bacteria and its secretions showed here depends on the time of bacteria‐epithelial cell contact, and also on the stage of Caco‐2 differentiation.

Colorectal cancer is the third most widely diagnosed cancer. Extracts from snails may modulate growth and development of colorectal cancer cells. The objective of this study was to determine the chemical composition of tissues derived from Helix aspersa Müller and red-ox properties of tissue extracts. Then, the influence of extracts and their fractions of different molecular weights on viability of Caco-2 cells was examined. Tissue lyophilisates contained antioxidants that could be important in the prevention of colorectal cancer. Moreover, we confirmed the presence of a wide array of compounds that might be used in treatment of this disease. The decrease of cell viability after the application of extracts from lyophilized mucus and foot tissues was affirmed. The effect of extract from mucus could be related to the content of some proteins and peptides, proper essential amino acids (EAA)/non-essential amino acids (NEAA) ratio, Met restriction and the presence of Cu, Ca, Zn, Se. The influence of the extract from foot tissues could be assigned additionally to the presence of eicosapentaenoic, α-linolenic, linoleic and γ-linolenic acids. The opposite effect was demonstrated by extract from lyophilized shells which increased cell viability. Further studies are needed to know whether dietary supplying of H. aspersa Müller tissues can be used as an approach in colorectal cancer management.

The growth hormone (GH) plays a key role in the regulation of metabolic processes in an organism. Determination of the correct structure and functioning of the growth hormone receptor (GHR) allowed for a more detailed research of its post-receptor regulators, which substantially influences its signal transduction. This review is focused on the description of the post-receptor inhibitors of the GHR-JAK2-STAT pathway, which is one of the most important pathways in the transduction of the somatotropic axis signal. The aim of this review is the short characterization of the main post-receptor inhibitors, such as: cytokine-inducible SH2-containing protein (CIS), Suppressors of Cytokine Signaling (SOCS) 1, 2 and 3, sirtuin 1 (SIRT1), protein inhibitors of activated STAT (PIAS) 1, 3 and PIAS4, protein tyrosine phosphatases (PTP) 1B and H1, Src homology 2 (SH2) domain containing protein tyrosine phosphatase (SHP) 1, 2 and signal regulatory protein (SIRP) α1. The equilibrium between these regulators activity and inhibition is of special concern because, as many studies showed, even slight imbalance may disrupt the GH activity causing serious diseases. The regulation of the described inhibitors expression and activity may be a point of interest for pharmaceutical industry.