Alkaloid Escholidine and Its Interaction with DNA Structures

Berberine, the most known quaternary protoberberine alkaloid (QPA), has been reported to inhibit the SIK3 protein connected with breast cancer. Berberine also appears to reduce the bcl-2 and XIAP expression-proteins responsible for the inhibition of apoptosis. As some problems in the therapy with berberine arose, we studied the DNA binding properties of escholidine, another QPA alkaloid. CD, fluorescence, and NMR examined models of i-motif and G-quadruplex sequences present in the n-myc gene and the c-kit gene. We provide evidence that escholidine does not induce stabilization of the i-motif sequences, while the interaction with G-quadruplex structures appears to be more significant.

MicroRNA-5100 Modulates Lung Cancer Cell Proliferation and Apoptosis via Inhibiting X-Linked Inhibitor of Apoptosis Protein (XIAP) Expression

This study assesses the miR-5100 expression and its function in human lung cancer. The expression of miR-5100 was analyzed by miScript miRNA method. Cancer cells were transfected with miR-5100 mimics (miR-5100), miR-5100 inhibitors (ASO-miR-5100), XIAP inhibitors (si-XIAP), negative controls (NC) followed by analysis of cell proliferation by MTT and apoptosis by flow cytometry, the expression of XIAP related proteins by Western blot. miR-5100’ target was predicted by bioinformatics website and verified by dual luciferase assay. Finally, a xenogeneic tumor inhibition model was established to detect tumor progression after treatments. Lung cancer cells and tissues exhibited significantly reduced miR-5100 level. Dual luciferase assay showed that miR-5100 bound XIAP 3′-UTR and reduced XIAP mRNA and protein level. Further, miR-5100 inhibited cell proliferation, increased apoptosis and the expression of cleaved-capsase-3 and cleaved-capsase-9, the XIAP downstream factor. Finally, miR-5100 inhibited tumor growth, decreased cellular proliferation and promoted apoptosis, accompanied by reduced XIAP expression in vivo. miR-5100 inhibits lung cancer cell proliferation and enhances apoptosis through inhibiting XIAP expression in vitro and in vivo.

LncRNA SLCO4A1-AS1 Accelerates Growth and Metastasis of Gastric Cancer via Regulation of the miR-149/XIAP Axis

ObjectiveRecently, long noncoding RNA SLCO4A1 antisense RNA 1 (SLCO4A1-AS1) has been shown to act as an oncogene in several cancer types; however, its role in gastric cancer (GC) and its underlying molecular mechanisms are yet to be elucidated.MethodsUsing the ENCORI database, we identified SLCO4A1-AS1, miR-149-5p (miR-149), and the X-linked inhibitor of apoptosis (XIAP) whose expressions were obviously changed in GC samples, and analyzed the correlation between their expressions in GC samples. Moreover, we explored the expression of SLCO4A1-AS1, miR-149, and XIAP in clinical samples and GC cell lines using RT-qPCR and western blotting assay; the correlation between them was analyzed using RNA immunoprecipitation and dual-luciferase reporter. CCK-8, colony formation, and Transwell assays were conducted to determine the effects of SLCO4A1-AS1, miR-149, and XIAP expression on cell proliferation, migration, and invasion, respectively. A nude mouse xenograft model was used to explore their function in xenograft growth.ResultsSLCO4A1-AS1 was significantly upregulated in the GC samples and cell lines, and a high level of SLCO4A1-AS1 was associated with an advanced tumor stage and shortened patient survival. Mechanistically, SLCO4A1-AS1 post-transcriptionally regulated XIAP by functioning as competing endogenous RNA in GC to sponge miR-149. Further functional assays revealed that the overexpression of miR-149 and knockdown of XIAP considerably inhibited GC cell viability and its migratory and invasive characteristics in vitro. SLCO4A1-AS1 knockdown also determined the function of GC cells but was diminished by the miR-149 inhibitor in vitro. Finally, we demonstrated that the deletion of SLCO4A1-AS1 suppressed tumor growth and metastasis in vivo.ConclusionsAltogether, these findings suggest that SLCO4A1-AS1 functions as a crucial oncogenic lncRNA in GC and it can facilitate GC tumor growth and metastasis by interacting with miR-149 and enhancing XIAP expression. Therefore, SLCO4A1-AS1 is a potential novel therapeutic target in GC treatment.

Expression of X-Linked Inhibitor of Apoptosis Protein (XIAP) in Breast Cancer Is Associated with Shorter Survival and Resistance to Chemotherapy

XIAP, the most potent inhibitor of cell death pathways, is linked to chemotherapy resistance and tumor aggressiveness. Currently, multiple XIAP-targeting agents are in clinical trials. However, the characterization of XIAP expression in relation to clinicopathological variables in large clinical series of breast cancer is lacking. We retrospectively analyzed non-metastatic, non-inflammatory, primary, invasive breast cancer samples for XIAP mRNA (n = 2341) and protein (n = 367) expression. XIAP expression was analyzed as a continuous value and correlated with clinicopathological variables. XIAP mRNA expression was heterogeneous across samples and significantly associated with younger patients’ age (≤50 years), pathological ductal type, lower tumor grade, node-positive status, HR+/HER2- status, and PAM50 luminal B subtype. Higher XIAP expression was associated with shorter DFS in uni- and multivariate analyses in 909 informative patients. Very similar correlations were observed at the protein level. This prognostic impact was significant in the HR+/HER2- but not in the TN subtype. Finally, XIAP mRNA expression was associated with lower pCR rate to anthracycline-based neoadjuvant chemotherapy in both uni- and multivariate analyses in 1203 informative patients. Higher XIAP expression in invasive breast cancer is independently associated with poorer prognosis and resistance to chemotherapy, suggesting the potential therapeutic benefit of targeting XIAP.

Verification of X-linked lymphoproliferative syndrome type 1 and 2 using a flow cytometry method

Х-linked lymphoproliferative syndrome (XLP) is a life-threatening primary immunodeficiency, characterized by hemophagocytic lymphohistiocytosis, lymphoproliferation and hypogammaglobulinemia. The most frequent forms of XLP – XLP1 and XLP2 – are caused by mutations of the SH2D1A and BIRС4/XIAP genes, coding for SAP and XIAP proteins, respectively. Early diagnosis is important as it allows to prevent severe complications by introducing specific therapy and proceed to hematopoietic stem cell transplantation. Here we describe validation of precise and fast flow cytometry-based method of XLP1 and XLP2 laboratory diagnostics. This study is supported by the Independent Ethics Committee and approved by the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. 89 patients from 2 months to 18 years of age seen at our Center from July 2016 to February 2020 with symptoms suspicious of XLP were included in the study. Decrease of SAP intracellular expression was found in 9 patients, and XIAP – in 10 patients. In all of them XLP diagnosis was confirmed by detection of SH2D1A or XIAP mutations, respectively. Female mutations carries from the families of these patients demonstrated abnormal expression of respective proteins. Analysis of the data allowed to calculated the optimized cut-off numbers for the SAP and XIAP expression, which was 50% and 80% in T lymphocytes (respectively) and 45% и 75% in NK lymphocytes (respectively). Specificity and sensitivity of the method was 100% for both proteins. Therefore the method of assessment of SAP and XIAP intracellular expression via flow cytometry allows fast and precise diagnostics of XLP1 and XLP2.

MON-LB77 Inhibitors of XIAP as Novel Therapeutic Agents in Thyroid Cancer

Treatment options for radioiodine-refractory epithelial thyroid cancer (ETC) are limited to tyrosine kinase inhibitors (TKIs), which are associated with significant adverse effects and are not curative. The inhibitors of apoptosis (IAP) family have oncogenic properties and overexpression of X-linked IAP (XIAP) in papillary thyroid carcinoma (PTC) is associated with a poor prognosis. Our group has previously reported a synergistic interaction between SMAC mimetics (SM) (IAP antagonists with XIAP and cIAP1 specificity), and PPARgamma agonists in granulosa cell tumors (1). Such an approach has not been explored in ETC. We hypothesize that SM may be efficacious alone or in combination with a secondary agent to inhibit proliferation, induce cell death and/or promote differentiation to resensitize cells to radioiodine. Four ETC-derived cell lines (K1, Nthy-ori 3-1, TPC-1 and SW-1736) were examined for cIAP1, cIAP2 and XIAP expression by RT-PCR. The K-1 and TPC-1 cell lines (PTC origin, BRAFV600E and PI3KCA mutation positive) were chosen to investigate the effects of an SM in combination with either a PPARgamma agonist (rosiglitazone) or a broad-spectrum TKI (sorafenib). Cell proliferation was examined using xCELLigence Real-Time Cell Analysis. Viability was assessed using total cell counts at 24 and 48 hours. In the four cell lines, we found abundant cIAP1 and XIAP expression and low cIAP2 expression. When an SM was used in combination with either rosiglitazone or sorafenib, we observed significant impairment of cell proliferation and viability with a clear morphological response. These effects appear SM-dependent, as SM treatment alone also showed significant effects on proliferation. However, these effects were enhanced when combined with sorafenib, which was ineffective alone. Markers of differentiation are currently being examined. Our findings suggest a novel role for SM in treating or redifferentiating radioiodine-refractory ETC. Clinically, this may involve lower doses of individual agents than when used alone, thereby reducing adverse effects. References1. Leung, D.T.H., et al., Combined PPARgamma Activation and XIAP Inhibition as a Potential Therapeutic Strategy for Ovarian Granulosa Cell Tumors. Mol Cancer Ther, 2019. 18(2): p. 364-375.

X-linked lymphoproliferative syndrome in mainland China: review of clinical, genetic, and immunological characteristic

X-linked lymphoproliferative syndrome (XLP) is a rare primary immunodeficiency disease that can be divided into two types: SAP deficiency (XLP1) and XIAP deficiency (XLP2), caused by mutations in the SH2D1A and XIAP genes, respectively. Few cases of XLP (particularly XIAP deficiency) have been reported in mainland China; hence, little is known about the characteristics of Chinese patients with XLP. We identified 13 and 7 patients with SAP and XIAP deficiency, respectively, in our center. Of our 20 patients, 19/20 (95%) presented with disease symptoms at a very early age: six in infancy and 13 in childhood. One XIAP- and three SAP-deficient patients died, while 3/7(42.9%) and 4/13(30.8%), respectively, developed hemophagocytic lymphohistiocytosis (HLH). Epstein-Barr virus (EBV) infection was significantly more common in SAP-deficient 10/13 (76.9%) than XIAP-deficient 2/7 (28.6%) patients, as was hypogammaglobulinemia (10/13 (76.9%) vs. 1/7 (14.3%)). None of the seven XIAP-deficient patients had colitis or lymphoma. Nine SAP-deficient patients and five XIAP-deficient patients showed markedly deficient SAP and XIAP expression, respectively, in lymphocytes. Significantly reduced levels of switched memory B cells were observed in six SAP-deficient patients with persistent hypogammaglobulinemia. One of 13 (7.7%) SAP-deficient patients and 1 of 7 (12.3%) XIAP-deficient patients have received HSCT treatment and are now alive and well; the other alive patients were waiting for HSCT. We also summarized clinical, genetic, and immunological characteristics of all 55 patients (including our 20 patients) reported in the literature in mainland China today.Conclusion: The overall characteristics of SAP deficiency in mainland China were consistent with those in previous reports, whereas manifestations of XIAP deficiency varied significantly. None of inflammatory bowel disease (IBD) has been reported among XIAP-deficient patients in our center; however, whether Chinese XIAP-deficient patients will develop colitis in the future warrants further investigation. HSCT is the only curative therapy for XLP and this therapy should be urgently considered.What is Known:• SAP and XIAP deficiencies share common clinical feature, HLH, whereas they also have their own specific manifestations.• IBD affects 25–30% of XIAP-deficient patients, which has been reported in other countries especially in European country and Japan.What is New:• This is the largest patient cohort study of XLP in China.• We firstly summarized the clinical features and outcomes of Chinese XIAP-deficient patients and found only 1 in 22 patients developed IBD and diet background may contribute to it; Asian SAP-deficient patients carrying SH2D1A R55X mutation were more prone to HLH.