Forkhead Box O3 (FOXO3) is a tumor suppressor whose activity is fine-tuned by post-translational modifications (PTMs). In this study, using the BT474 breast cancer cells and a recently established lapatinib resistant (BT474-Lap^R) cell line, we observed that higher FOXO3 and acetylated (Ac)-FOXO3 levels correlate with lapatinib sensitivity. Subsequent ectopic expression of EP300 led to an increase in acetylated-FOXO3 in sensitive but not in resistant cells. Drug sensitivity assays revealed that sensitive BT474 cells show increased lapatinib cytotoxicity upon over-expression of wild-type but not acetylation-deficient EP300. Moreover, FOXO3 recruitment to target gene promoters is associated with target gene expression and drug response in sensitive cells and the inability of FOXO3 to bind its target genes correlates with lapatinib-resistance in BT474-Lap^R cells. In addition, using SIRT1/6 specific siRNAs and chemical inhibitor, we also found that sirtuin 1 and -6 (SIRT1 and -6) play a part in fine-tuning FOXO3 acetylation and lapatinib sensitivity. Consistent with this, immunohistochemistry results from different breast cancer subtypes showed that high SIRT6/1 levels are associated with constitutive high FOXO3 expression which is related to FOXO3 deregulation/inactivation and poor prognosis in breast cancer patient samples. Collectively, our results suggest the involvement of FOXO3 acetylation in regulating lapatinib sensitivity of HER2-positive breast cancers.

The tannery industry produces one of the worst contaminants, and unsafe disposal in nearby waterbodies and landfills has become an imminent threat to public health, especially when the resulting multidrug-resistant bacteria and heavy metals enter community settings and animal food chains. In this study, we have collected 10 tannery wastewater (TWW) samples and 10 additional non-tannery wastewater (NTW) samples to compare the chemical oxygen demand (COD), pH, biological oxygen demand (BOD), dissolved oxygen (DO), total dissolved solids (TDS), chromium concentration, bacterial load, and antibiotic resistance profiles. While COD, pH, and chromium concentration data were previously published from our lab, this part of the study uncovers that TWW samples had a significantly higher bacterial load, compared to the non-tannery wastewater samples (5.89 × 10⁴ and 9.38 × 10³ cfu/mL, respectively), higher BOD and TDS values, and significantly lower DO values. The results showed that 53.4, 46.7, 40.0, and 40.0% of the TWW isolates were resistant to ceftriaxone, erythromycin, nalidixic acid, and azithromycin, respectively. On the other hand, 20.0, 30.0, 50.0, and 40.0% of the NTW isolates were resistant to the same antibiotics, respectively. These findings suggest that the TWW isolates were more resistant to antibiotics than the NTW isolates. Moreover, the TWW isolates exhibited higher multidrug resistance than the NTW isolates, 33.33, and 20.00%, respectively. Furthermore, spearman correlation analysis depicts that there is a negative correlation between BOD and bacterial load up to a certain level (r = − 0.7749, p = 0.0085). In addition, there is also a consistent negative correlation between COD and bacterial load (r = − 0.7112, p = 0.0252) and TDS and bacterial load (r = − 0.7621, p = 0.0104). These findings suggest that TWW could pose a significant risk to public health and the environment and highlight the importance of proper wastewater treatment in tannery industries.

Urinary tract infections (UTIs) caused by Escherichia coli pose significant public health risks, particularly in developing countries like Bangladesh. This study aimed to elucidate resistance patterns among UTI isolates and comprehensively investigate the mutational spectrum and its impact on drug-microbe interactions. We collected and identified E. coli isolates from hospitalized UTI patients at Dhaka Medical College Hospital and determined their resistance patterns using the disc diffusion method and broth microdilution. Quinolone resistance-determining regions (QRDRs) of the target genes (gyrA, gyrB, parC, and parE) associated with fluoroquinolone resistance were amplified by polymerase chain reaction (PCR) and analyzed through BTSeq™ sequencing for mutations, followed by molecular docking analysis using PyMOL and AutoDock for the protein-quinolone binding affinity (PQBA) study. All isolates (100 %) displayed multidrug resistance, with chloramphenicol (16 % resistant) and colistin (28 % resistant) demonstrating superior efficacy compared to other antibiotics. The isolates resistant to colistin, as determined by disc diffusion testing, exhibited remarkably high minimum inhibitory concentrations (MICs), with one isolate registering an MIC exceeding 512 µg/mL. Alarming resistance rates were observed for five antibiotic classes, except for polymyxins (28 % resistant) and protein synthesis inhibitors (48 % resistant). Fifty-two percent (52 %) of the isolates exhibited resistance to all five tested quinolones. Sequence analysis revealed a novel L88Q mutation in ParC, affecting PQBA and binding conformation. Additionally, three ParC mutations (S80I, E84V, and E84G) and two ParE mutations (S458A and I529L) were identified, which had not been previously reported in Bangladesh. Among these, S80I appeared in all isolates. Double-mutations (S83L+D87N) in GyrA, L88Q and S80I in ParC, and I529L in ParE were identified as key drivers of fluoroquinolone resistance. Our findings underscore the accumulation of significant mutations within QRDRs of UTI isolates, potentially compromising fluoroquinolone efficacy. The emergence of these novel mutations warrants further investigation to impede their dissemination and combat quinolone resistance.

Multidrug resistance (MDR) is one of the deadliest public health concerns of the 21st century, rendering many powerful antibiotics ineffective. The current study provides important insights into the prevalence and mechanisms of antibiotic resistance in hospital wastewater isolates. In this study, we determined the MDR profile of 68 bacterial isolates collected from five different hospitals in Dhaka, Bangladesh. Of them, 48 bacterial isolates were identified as Enterobacteriaceae. Additionally, we investigated the prevalence and distribution of five beta-lactam resistance genes, as well as quinolone resistance mechanisms among the isolates. The results of this study showed that 87% of the wastewater isolates were resistant to at least three different antibiotic classes, as revealed using the disc diffusion method. Resistance to β-lactams was the most common, with 88.24% of the isolates being resistant, closely followed by macrolides (80.88% resistant). Polymyxin was found to be the most effective against wastewater isolates, with 29.41% resistant isolates. The most common β-lactam resistance genes found in wastewater isolates were bla_TEM (76.09%), bla_CTX-M1 (71.74%), and bla_NDM (67.39%). Two missense mutations in the quinolone resistance-determining region (QRDR) of gyrA (S83L and D87N) and one in both parC (S80I) and parE (S458A) were identified in all isolates, and one in parE (I529L), which had not previously been identified in Bangladesh. These findings suggest that hospital wastewater acts as an important reservoir of antibiotic-resistant bacteria wherein resistance mechanisms to β-lactams and fluoroquinolones are obvious. Our data also emphasize the need for establishing a nationwide surveillance system for antibiotic resistance monitoring to ensure that hospitals sanitize their wastewater before disposal, and regulation to ensure hospital wastewater is kept away from community settings.