Abstract. Our aim was to determine the association of human papillomavirus (HPV) infection with the expression of ATPase family AAA domain containing 3A (ATAD3A), an anti-autophagy factor, in uterine cervical cancer (UCC). The HPV genotype was determined by an Easychip HPV blot assay. ATAD3A expression was determined by immunohistochemical staining. High-risk HPV (hrHPV) was detected in 184 (88.9%) of 207 UCC cases. ATAD3A expression was detected in 164 (79.2%) UCC cases. A significant correlation was found between ATAD3A expression and the presence of hrHPV (p<0.001), FIGO stage (p=0.014), lymph node involvement (p=0.001), c-MET expression (p<0.001), interleukin-8 (p=0.03) and patient survival (p=0.0016). Interestingly, silencing of E6/E7 expression decreased ATAD3A expression and cell survival. Moreover, knockdown of ATAD3A (ATAD3A kd ) expression or addition of resveratrol, increased cellular autophagy and apoptosis and reduced drug resistance. Resveratrol reduced ATAD3A expression, and increased abrasion of the mitochondrial outer membrane as well as numbers of autophagosomes, the phenomena that were frequently found in ATAD3A kd cells. In conclusion, our results show that HPV infection correlates with increased ATAD3A expression and drug resistance in UCC. Persistent HPV infection may stabilize ATAD3A expression to inhibit cell autophagy and apoptosis as well as to increase drug resistance. IntroductionUterine cervical cancer (UCC) is the most prevalent cancer, and the fifth leading cause of cancer-related deaths in Taiwanese women (1). High incidence and mortality of the disease was in part due to the conservative attitude toward the Papanicolaou smear, because even though the disease could be detected at the early stages the method was considered intrusive, and in part due to the high infection rate of human papillomavirus (HPV) among the diseased women (2). HPV infection is a potential etiologic cause for UCC development (3,4). Among 95 known HPV (5), genotypes 16, 18, 52 and 58 are categorized as high-risk and most frequently detected in Taiwanese UCC patients (6-9). Carcinogenicity of the high-risk HPV (hrHRV) is closely associated with E6 and E7 proteins, which can respectively inhibit activities of tumor suppressors, p53 and retinoblastoma protein (pRB), to interrupt cell growth regulation (10). Besides carcinogenesis, persistent HPV infection further correlates with tumor recurrence, cancer cell radiosensitivity and the resulting poor prognosis (11-13).Oncogene activation is also crucial for tumorigenesis and cancer progression; in particular, genes that are associated with disease advancement and, possibly, resistance to irradiation and anticancer chemotherapeutics. By using differential display, we have identified overexpression of dihydrodiol dehydrogenase (DDH) in non-small cell lung cancer (14). Using microarrays, we further found that DDH was overexpressed in cisplatin-resistant ovarian cancer cells (15). Clinically, patients with elevated DDH have a higher tumor recurrence rate and lymph node...
Streptococcus sanguinis, dominant in the oral microbiome, is the only known streptococcal species possessing a pil gene cluster for the biosynthesis of type IV pili (Tfp). Although this cluster is commonly present in the genome of S. sanguinis, most of the strains do not express Tfp-mediated twitching motility. Thus, this study was designed to investigate the biological functions encoded by the cluster in the twitching-negative strain S. sanguinis SK36. We found that the cluster was transcribed as an operon, with three promoters located 5= to the cluster and one in the intergenic region between SSA_2307 and SSA_2305. Studies using promoter-cat fusion strains revealed that the transcription of the cluster was mainly driven by the distal 5= promoter, which is located more than 800 bases 5= to the first gene of the cluster, SSA_2318. Optimal expression of the cluster occurred at the early stationary growth phase in a CcpA-dependent manner, although a CcpA-binding consensus is absent in the promoter region. Expression of the cluster resulted in a short hairlike surface structure under transmission electron microscopy. Deletion of the putative pilin genes (SSA_2313 to SSA_2315) abolished the biosynthesis of this structure and significantly reduced the adherence of SK36 to HeLa and SCC-4 cells. Mutations in the pil genes downregulated biofilm formation by S. sanguinis SK36. Taken together, the results demonstrate that Tfp of SK36 are important for host cell adherence, but not for motility, and that expression of the pil cluster is subject to complex regulation. IMPORTANCE The proteins and assembly machinery of the type IV pili (Tfp) are conserved throughout bacteria and archaea, and yet the function of this surface structure differs from species to species and even from strain to strain. As seen in Streptococcus sanguinis SK36, the expression of the Tfp gene cluster results in a hairlike surface structure that is much shorter than the typical Tfp. This pilus is essential for the adherence of SK36 but is not involved in motility. Being a member of the highly diverse dental biofilm, perhaps S. sanguinis could more effectively utilize this structure to adhere to host cells and to interact with other microbes within the same niche.
BackgroundStreptococcus salivarius is an abundant isolate of the human oral microbiota. Since both pH and glucose availability fluctuate frequently in the oral cavity, the goal of this study was to investigate regulation by CodY, a conserved pleiotropic regulator of Gram positive bacteria, in response to these two signals. The chemostat culture system was employed to precisely control the growth parameters, and the transcriptomes of wild-type S. salivarius 57.I and its CodY-null derivative (ΔcodY) grown at pH 7 and 5.5, with limited and excessive glucose supply were determined.ResultsThe transcriptomic analysis revealed that CodY was most active at pH 7 under conditions of glucose limitation. Based on whether a CodY binding consensus could be located in the 5′ flanking region of the identified target, the transcriptomic analysis also found that CodY shaped the transcriptome via both direct and indirect regulation. Inactivation of codY reduced the glycolytic capacity and the viability of S. salivarius at pH 5.5 or in the presence of H2O2. Studies using the Galleria mellonella larva model showed that CodY was essential for the toxicity generated from S. salivarius infection, suggesting that CodY regulation was critical for immune evasion and systemic infections. Furthermore, the CodY-null mutant strain exhibited a clumping phenotype and reduced attachment in biofilm assays, suggesting that CodY also modulates cell wall metabolism. Finally, the expression of genes belonging to the CovR regulon was affected by codY inactivation, but CodY and CovR regulated these genes in opposite directions.ConclusionsMetabolic adaptation in response to nutrient availability and growth pH is tightly linked to stress responses and virulence expression in S. salivarius. The regulation of metabolism by CodY allows for the maximal utilization of available nutrients and ATP production. The counteractive regulation of the CovR regulon could fine tune the transcriptomes in response to environmental changes.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4781-z) contains supplementary material, which is available to authorized users.
GlnR-mediated repression of the GlnR regulon at acidic pH is required for optimal acid tolerance in Streptococcus mutans, the etiologic agent for dental caries. Unlike most streptococci, the GlnR regulon is also regulated by newly identified PmrA (SMUGS5_RS05810) at the transcriptional level in S. mutans GS5. Results from gel mobility shift assays confirmed that both GlnR and PmrA recognized the putative GlnR box in the promoter regions of the GlnR regulon genes. By using a chemostat culture system, we found that PmrA activated the expression of the GlnR regulon at pH 7, and that this activation was enhanced by excess glucose. Deletion of pmrA (strain ΔPmrA) reduced the survival rate of S. mutans GS5 at pH 3 moderately, whereas the GlnR mutant (strain ΔGlnR) exhibited an acid-sensitive phenotype in the acid killing experiments. Elevated biofilm formation in both ΔGlnR and ΔPmrA mutant strains is likely a result of indirect regulation of the GlnR regulon since GlnR and PmrA regulate the regulon differently. Taken together, it is suggested that activation of the GlnR regulon by PmrA at pH 7 ensures adequate biosynthesis of amino acid precursor, whereas repression by GlnR at acidic pH allows greater ATP generation for acid tolerance. The tight regulation of the GlnR regulon in response to pH provides an advantage for S. mutans to better survive in its primary niche, the oral cavity.
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