Potential association between ITPKC genetic variations and Hirschsprung disease

Immune-related genes STIM1, ITPKC and PELI1 polymorphisms are associated with risk of colorectal cancer

OBJECTIVES

STIM1, ITPKC and PELI1 are all immune-related genes that take part in the T cell activation, toll-like receptor and IL1 receptor pathways. The goal of this study was to evaluate the associations between STIM1, ITPKC and PELI1 polymorphisms and colorectal cancer (CRC) risk.

METHODS

Six single nucleotide polymorphisms (SNPs) in STIM1, ITPKC and PELI1 were genotyped using a MassARRAY platform in a discovery cohort including 480 CRC cases and 480 healthy individuals and validated in a replication cohort including 505 CRC cases and 510 controls.

RESULTS

The minor alleles of rs3794050, rs3750996 and rs2607420 were associated with an increased CRC risk (P < 0.05). In contrast, the minor allele of rs329497 was correlated with reduced disease risk (P = 0.025). Genetic model analysis showed that rs3794050 was related to an increased risk of disease in recessive and log-additive models (P < 0.05); rs3750996 had a strong correlation with CRC risk under all genetic models (P < 0.02); rs2607420 was correlated with an increased risk of disease in dominant and log-additive models (P < 0.01); whereas the protective effect of rs329497 on CRC risk was observed in dominant and log-additive models (P < 0.05). Finally, the association between the above SNPs and CRC risk was validated in a replication cohort (P < 0.05).

CONCLUSIONS

Our results could be helpful for the early screening of individuals with high CRC risk.

ITPKC as a Prognostic and Predictive Biomarker of Neoadjuvant Chemotherapy for Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with higher mortality than the others. Pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is considered as a surrogate to predict survival. Inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) is a negative regulator of T cell activation, and reduction in ITPKC function is known to promote Kawasaki disease. Given the role of tumor infiltrating lymphocytes in NAC and since TNBC has the most abundant immune cell infiltration in breast cancer, we hypothesized that the ITPKC expression level is associated with NAC response and prognosis in TNBC. The ITPKC gene was expressed in the mammary gland, but its expression was highest in breast cancer cells among other stromal cells in a bulk tumor. ITPKC expression was highest in TNBC, associated with its survival, and was its independent prognostic factor. Although high ITPKC was not associated with immune function nor with any immune cell fraction, low ITPKC significantly enriched cell proliferation-related gene sets in TNBC. TNBC with low ITPKC achieved a significantly higher pCR rate after NAC. To the best of our knowledge, this is the first report to demonstrate that ITPKC gene expression may be useful as a prognostic and predictive biomarker in TNBC.

Regulation of Hematopoietic Cell Development and Function Through Phosphoinositides

One of the most paramount receptor-induced signal transduction mechanisms in hematopoietic cells is production of the lipid second messenger phosphatidylinositol(3,4,5)trisphosphate (PIP₃) by class I phosphoinositide 3 kinases (PI3K). Defective PIP₃ signaling impairs almost every aspect of hematopoiesis, including T cell development and function. Limiting PIP₃ signaling is particularly important, because excessive PIP₃ function in lymphocytes can transform them and cause blood cancers. Here, we review the key functions of PIP₃ and related phosphoinositides in hematopoietic cells, with a special focus on those mechanisms dampening PIP₃ production, turnover, or function. Recent studies have shown that beyond “canonical” turnover by the PIP₃ phosphatases and tumor suppressors phosphatase and tensin homolog (PTEN) and SH2 domain-containing inositol-5-phosphatase-1 (SHIP-1/2), PIP₃ function in hematopoietic cells can also be dampened through antagonism with the soluble PIP₃ analogs inositol(1,3,4,5)tetrakisphosphate (IP₄) and inositol-heptakisphosphate (IP₇). Other evidence suggests that IP₄ can promote PIP₃ function in thymocytes. Moreover, IP₄ or the kinases producing it limit store-operated Ca²⁺ entry through Orai channels in B cells, T cells, and neutrophils to control cell survival and function. We discuss current models for how soluble inositol phosphates can have such diverse functions and can govern as distinct processes as hematopoietic stem cell homeostasis, neutrophil macrophage and NK cell function, and development and function of B cells and T cells. Finally, we will review the pathological consequences of dysregulated IP₄ activity in immune cells and highlight contributions of impaired inositol phosphate functions in disorders such as Kawasaki disease, common variable immunodeficiency, or blood cancer.