Inhibition of non-small cell lung cancer (NSCLC) proliferation through targeting G6PD.

Background: Mounting evidence has linked cancer metabolic reprogramming with altered redox homeostasis. The pentose phosphate pathway (PPP) is one of the key metabolism-related pathways that has been enhanced to promote cancer growth. The glucose 6-phosphate dehydrogenase (G6PD) of this pathway generates reduced nicotinamide adenine dinucleotide phosphate (NADPH), which is essential for controlling cellular redox homeostasis. Objective: This research aimed to investigate the growth-promoting effects of G6PD in non-small cell lung cancer (NSCLC). Methods: Clinical characteristics and G6PD expression levels in lung tissues of 64 patients diagnosed with lung cancer at the King Chulalongkorn Memorial Hospital (Bangkok, Thailand) during 2009-2014 were analyzed. G6PD activity in NSCLC cell lines, including NCI-H1975 and NCI-H292, was experimentally inhibited using DHEA and siG6PD to study cancer cell proliferation and migration. Results: The positive expression of G6PD in NSCLC tissues was detected by immunohistochemical staining and was found to be associated with squamous cells. G6PD expression levels and activity also coincided with the proliferation rate of NSCLC cell lines. Suppression of G6PD-induced apoptosis in NSCLC cell lines by increasing Bax/Bcl-2 ratio expression. The addition of D-(-)-ribose, which is an end-product of the PPP, increased the survival of G6PD-deficient NSCLC cell lines. Conclusion: Collectively, these findings demonstrated that G6PD might play an important role in the carcinogenesis of NSCLC. Inhibition of G6PD might provide a therapeutic strategy for the treatment of NSCLC.

Evaluating the performance of automated UV enzymatic assay for screening of glucose 6-phosphate dehydrogenase deficiency.

INTRODUCTION: A precise and reliable screening assay for glucose 6-phosphate dehydrogenase (G6PD) deficiency would greatly help avoiding unwanted outcomes due to bilirubin neurotoxicity in neonatal jaundice and antimalarial-induced haemolytic anaemia in malaria patients. Currently, available assays are laborious and require sophisticated laboratory expertise. This study aimed to evaluate the performance of a recently introduced automated screening assay for G6PD deficiency by comparing with a routine spectrophotometric assay. METHODS: An automated UV-based enzymatic (Mindray, PRC) and spectrophotometric assays were performed simultaneously in parallel to determine G6PD activity in 251 blood samples from the subjects. RESULTS: The median G6PD activity value from spectrophotometric assay was significantly lower than that of from the automated assay. The mean difference was -2.0 U/g haemoglobin (-7.3 to 3.2; P < 0.0001). The mean activity values of both assays were strongly correlated with Pearson's correlation coefficient of r = 0.8. Cohen's kappa statistics between assays was 0.77 (0.70-0.83). The sensitivity, specificity, positive and negative predictive values of the automated assay were 85.7%, 99.2%, 85.7%, 99.2%, respectively. The sensitivity and positive predictive values of the automated assay for identifying intermediate G6PD activity levels were 40.0% and 25.0%, respectively. Genotyping was performed to confirm G6PD deficient and intermediate samples. The turnaround time for 40 samples was 60 minutes for the automated assay and 300 minutes for spectrophotometric assay. CONCLUSION: The automated assay for the detection of G6PD deficiency is comparable to a routine spectrophotometric assay and help reducing sample handling time. However, the assay shows limitation in identifying individuals with G6PD intermediate.

HAART has no major impact on hematological and plasma bilirubin changes in HIV-infected patients with congenital G-6-PD deficiency.

Hematological effects of antiretroviral (ARV) drugs in HIV-infected patients with glucose-6-phosphate dehydrogenase (G-6-PD) deficiency are unclear. The aim of this study was to assess effects of highly active antiretroviral therapy (HAART) on hematological and plasma bilirubin changes in these patients. A hundred and nine HIV-infected Thai patients were tested for G-6-PD deficiency and its variant by using fluorescent spot test and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, accordingly. Changes of hematological parameters and plasma bilirubin at baseline and 6 months of HAART were analyzed in G-6-PD deficiency patients. G-6-PD deficiency was found in 10 (9.17%) patients and G-6-PD Canton1376G>T was the most frequent. Of these, 3 patients had coinheritance of G-6-PD deficiency and thalassemia. Increased mean levels of lymphocyte counts, CD4⁺ T-cells, mean corpuscular hemoglobin (MCH) and hemoglobin from baseline to 6 months of HAART were observed. Whereas, mean levels of total bilirubin and direct bilirubin at baseline were not significantly different from those at 6 months of HAART. Therefore, HAART did not cause hemolytic anemia and hyperbilirubinemia in HIV-infected patients with G-6-PD deficiency. On the other hand, the effective use of HAART is associated with improvements in hemoglobin and MCH levels of these patients.