Recombinant Escherichia coli as a gene delivery vector into airway epithelial cells

Abstract To transfer genes into airway epithelial cells, we have generated auxotrophic dap Escherichia coli BM2710 mutant that expresses the invasin of Yersinia pseudotuberculosis and the listeriolysin of Listeria monocytogenes. E. coli BM2710 harboring a plasmid carrying the gfp gene was incubated with immortalized normal or cystic fibrosis (CF) airway epithelial cells or with primary bronchial epithelial cells grown as an explant-outgrowth cell culture model. Approximately 2% of immortalized cells expressed GFP. Few primary cells were transfected that were always poorly differentiated and located at the edge of the outgrowth. This was consistent with the expression of h1-integrins only on these cells and with the required interaction for cell entry of E. coli expressing the invasin with h1-integrins. The subsequent intracellular trafficking of E. coli BM2710 studied by confocal and electronic microscopy showed that the E. coli-containing phagosomes rapidly matured into phagolysosomes. This is the first demonstration that recombinant bacteria are able to transfer genes into primary airway epithelial cells, provided that they are able to invade the cells

Galectin-3 immunodetection in follicular thyroid neoplasms: a prospective study on fine-needle aspiration samples

Fine-needle aspiration cytology, which is well established to be accurate for the diagnosis of thyroid cancer, may be inconclusive for the follicular thyroid neoplasms. As galectin-3 was suggested to be a marker of malignant thyrocytes, we investigated whether this protein might be helpful in the diagnosis of aspirates classified as undeterminate by cytology. After establishing an easy processing of aspirates for galectin-3 immunodetection, a series of aspirates categorised as benign (n=63), malignant (n=17) or undeterminate (n=34) was prospectively analysed for galectin-3. Only the patients with malignant or undeterminate lesions underwent surgery. Most lesions (86%) diagnosed as malignant by cytology or after surgery were positive for galectin-3. The majority of lesions (94%) classified as benign by cytology or after surgery was negative for galectin-3. The positive and negative predictive values were 83 and 95%, respectively. When focusing on the undeterminate lesions, the sensitivity and specificity were 75 and 90%, respectively, while the positive and negative predictive values were 82 and 87%, respectively. The specificity and the positive predictive value were higher (100%) when considering the percentage of stained cells. Altogether these results show that galectin-3 constitutes a useful marker in the diagnosis of thyroid lesions classified as undeterminate by conventional cytology

Triple Therapy for Cystic Fibrosis Phe508del–Gating and –Residual Function Genotypes

BACKGROUND Elexacaftor–tezacaftor–ivacaftor is a small-molecule cystic fibrosis transmembrane conductance regulator (CFTR) modulator regimen shown to be efficacious in patients with at least one Phe508del allele, which indicates that this combination can modulate a single Phe508del allele. In patients whose other CFTR allele contains a gating or residual function mutation that is already effectively treated with previous CFTR modulators (ivacaftor or tezacaftor–ivacaftor), the potential for additional benefit from restoring Phe508del CFTR protein function is unclear. METHODS We conducted a phase 3, double-blind, randomized, active-controlled trial involving patients 12 years of age or older with cystic fibrosis and Phe508del–gating or Phe508del–residual function genotypes. After a 4-week run-in period with ivacaftor or tezacaftor–ivacaftor, patients were randomly assigned to receive elexacaftor–tezacaftor–ivacaftor or active control for 8 weeks. The primary end point was the absolute change in the percentage of predicted forced expiratory volume in 1 second (FEV1) from baseline through week 8 in the elexacaftor–tezacaftor–ivacaftor group. RESULTS After the run-in period, 132 patients received elexacaftor–tezacaftor–ivacaftor and 126 received active control. Elexacaftor–tezacaftor–ivacaftor resulted in a percentage of predicted FEV1 that was higher by 3.7 percentage points (95% confidence interval [CI], 2.8 to 4.6) relative to baseline and higher by 3.5 percentage points (95% CI, 2.2 to 4.7) relative to active control and a sweat chloride concentration that was lower by 22.3 mmol per liter (95% CI, 20.2 to 24.5) relative to baseline and lower by 23.1 mmol per liter (95% CI, 20.1 to 26.1) relative to active control (P<0.001 for all comparisons). The change from baseline in the Cystic Fibrosis Questionnaire–Revised respiratory domain score (range, 0 to 100, with higher scores indicating better quality of life) with elexacaftor–tezacaftor–ivacaftor was 10.3 points (95% CI, 8.0 to 12.7) and with active control was 1.6 points (95% CI, −0.8 to 4.1). The incidence of adverse events was similar in the two groups; adverse events led to treatment discontinuation in one patient (elevated aminotransferase level) in the elexacaftor–tezacaftor–ivacaftor group and in two patients (anxiety or depression and pulmonary exacerbation) in the active control group. CONCLUSIONS Elexacaftor–tezacaftor–ivacaftor was efficacious and safe in patients with Phe508del–gating or Phe508del–residual function genotypes and conferred additional benefit relative to previous CFTR modulators. (Funded by Vertex Pharmaceuticals; VX18-445-104 ClinicalTrials.gov number, NCT04058353.

Decreased transcription-coupled nucleotide excision repair capacity is associated with increased p53- and MLH1-independent apoptosis in response to cisplatin

Abstract Background One of the most commonly used classes of anti-cancer drugs presently in clinical practice is the platinum-based drugs, including cisplatin. The efficacy of cisplatin therapy is often limited by the emergence of resistant tumours following treatment. Cisplatin resistance is multi-factorial but can be associated with increased DNA repair capacity, mutations in p53 or loss of DNA mismatch repair capacity. Methods RNA interference (RNAi) was used to reduce the transcription-coupled nucleotide excision repair (TC-NER) capacity of several prostate and colorectal carcinoma cell lines with specific defects in p53 and/or DNA mismatch repair. The effect of small inhibitory RNAs designed to target the CSB (Cockayne syndrome group B) transcript on TC-NER and the sensitivity of cells to cisplatin-induced apoptosis was determined. Results These prostate and colon cancer cell lines were initially TC-NER proficient and RNAi against CSB significantly reduced their DNA repair capacity. Decreased TC-NER capacity was associated with an increase in the sensitivity of tumour cells to cisplatin-induced apoptosis, even in p53 null and DNA mismatch repair-deficient cell lines. Conclusion The present work indicates that CSB and TC-NER play a prominent role in determining the sensitivity of tumour cells to cisplatin even in the absence of p53 and DNA mismatch repair. These results further suggest that CSB represents a potential target for cancer therapy that may be important to overcome resistance to cisplatin in the clinic

Increasing the bactofection capacity of a mammalian expression vector by removal of the f1 ori

Bacterial-mediated cancer therapy has shown great promise in in vivo tumour models with increased survival rates post-bacterial treatment. Improving efficiency of bacterial-mediated tumour regression has focused on controlling and exacerbating bacterial cytotoxicity towards tumours. One mechanism that has been used to carry this out is the process of bactofection where post-invasion, bacteria deliver plasmid-borne mammalian genes into target cells for expression. Here we utilised the cancer-targeting Salmonella Typhimurium strain, SL7207, to carry out bactofection into triple negative breast cancer MDA-MB-231 cells. However, we noted that post-transformation with the commonly used mammalian expression vector pEGFP, S. Typhimurium became filamentous, attenuated and unable to invade target cells efficiently. Filamentation did not occur in Escherichia coli-transformed with the same plasmid. Further investigation identified the region inducing S. Typhimurium filamentation as being the f1 origin of replication (f1 ori), an artefact of historic use of mammalian plasmids for single stranded DNA production. Other f1 ori-containing plasmids also induced the attenuated phenotype, while removal of the f1 ori from pEGFP restored S. Typhimurium virulence and increased the bactofection capacity. This work has implications for interpretation of prior bactofection studies employing f1 ori-containing plasmids in S. Typhimurium, while also indicating that future use of S. Typhimurium in targeting tumours should avoid the use of these plasmids

Severity of chronic asthma

How is the severity of chronic asthma best assessed and what are the mechanisms that determine its severity? These two questions are diYcult to answer because, until we understand what asthma is, it is not possible to describe its severity in a given individual. In the shorter Oxford English Dictionary severity in relation to disease is defined as “vio-lence or acuteness of illness ” or “grievousness of aZiction”. The former definition is useful for exacerba-tions or attacks. Clinicians have had little diYculty in agreeing on defining the severity of attacks.1 2 The latter definition seems relevant to the severity of the chronic dis-ease which is the subject of these comments. Until recently the severity of asthma was rarely assessed, but with the increasing use of guidelines and drug trials the concept of severity has emerged. The GINA guidelines1 classify th