ABSTRACT
Chronic lymphocytic leukemias (CLLs) with unmutated (U-CLL) or mutated (M-CLL) IGHV have variable features of immunosuppression, possibly influenced by those CLL cells activated to produce interleukin 10 (IL-10). The two subsets differ in their levels of anergy, defined by low surface immunoglobulin M levels/signaling capacity, and in their DNA methylation profile, particularly variable in M-CLL. We have now found that levels of IL-10 produced by activated CLL cells were highly variable. Levels were higher in M-CLL than in U-CLL and correlated with anergy. DNA methylation analysis of IL10 locus revealed two previously uncharacterized 'variably methylated regions' (CLL-VMRs1/2) in the gene body, but similarly low methylation in the promoter of both U-CLL and M-CLL. CLL-VMR1/2 methylation was lower in M-CLL than in U-CLL and inversely correlated with IL-10 induction. A functional signal transducer and activator of transcription 3 (STAT3) binding site in CLL-VMR2 was confirmed by proximity ligation and luciferase assays, whereas inhibition of SYK-mediated STAT3 activation resulted in suppression of IL10. The data suggest epigenetic control of IL-10 production. Higher tumor load may compensate the reduced IL-10 production in U-CLL, accounting for clinical immunosuppression in both subsets. The observation that SYK inhibition also suppresses IL-10 provides a potential new rationale for therapeutic targeting and immunological rescue by SYK inhibitors in CLL.
Subject(s)
DNA Methylation , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Variable Region/genetics , Interleukin-10/biosynthesis , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Mutation , Humans , Interleukin-10/genetics , STAT3 Transcription Factor/metabolism , Syk Kinase/antagonists & inhibitors , Syk Kinase/physiologyABSTRACT
Actinic keratoses (AK) are common, premalignant lesions cause mainly by UV DNA damage. Progression into squamous cell carcinoma may be influenced by other several factors such as chronic chemical exposure or viral infection. A carcinogenic role of Human Papillomaviruses (HPV) in early steps of skin tumour development was recently hypothesized; moreover the presence of HPV DNA seems to be higher in cancer precursor lesions. The aim of this work is to identify the presence of HPV DNA in biopsies from Actinic Keratoses (AK) and from normal skin samples collected from dermatological healthy subjects in Italy, in order to evaluate the severity and the clinical evolution of the HPV positive lesions. The DNA test revealed 37% HPV positivity in AK patients versus 0% in the control group; many different genotypes and variants were identified by direct sequencing of PCR product. The HPV positive AK were usually clinically indistinguishable from the HPV negative. All AK lesions were removed by laser treatment, but AK lesions recurred in all HPV positive patients after a period of 45-60 days whereas the same disappeared in the HPV negative ones. These data permit to hypothesize that the presence of HPV DNA could be an aggravating factor for AK lesion severity and recurrence.
