Epigenetic SMAD3 Repression in Tumor-Associated Fibroblasts Impairs Fibrosis and Response to the Antifibrotic Drug Nintedanib in Lung Squamous Cell Carcinoma.

The tumor-promoting fibrotic stroma rich in tumor-associated fibroblasts (TAF) is drawing increased therapeutic attention. Intriguingly, a trial with the antifibrotic drug nintedanib in non-small cell lung cancer reported clinical benefits in adenocarcinoma (ADC) but not squamous cell carcinoma (SCC), even though the stroma is fibrotic in both histotypes. Likewise, we reported that nintedanib inhibited the tumor-promoting fibrotic phenotype of TAFs selectively in ADC. Here we show that tumor fibrosis is actually higher in ADC-TAFs than SCC-TAFs in vitro and patient samples. Mechanistically, the reduced fibrosis and nintedanib response of SCC-TAFs was associated with increased promoter methylation of the profibrotic TGFß transcription factor SMAD3 compared with ADC-TAFs, which elicited a compensatory increase in TGFß1/SMAD2 activation. Consistently, forcing global DNA demethylation of SCC-TAFs with 5-AZA rescued TGFß1/SMAD3 activation, whereas genetic downregulation of SMAD3 in ADC-TAFs and control fibroblasts increased TGFß1/SMAD2 activation, and reduced their fibrotic phenotype and antitumor responses to nintedanib in vitro and in vivo. Our results also support that smoking and/or the anatomic location of SCC in the proximal airways, which are more exposed to cigarette smoke particles, may prime SCC-TAFs to stronger SMAD3 epigenetic repression, because cigarette smoke condensate selectively increased SMAD3 promoter methylation. Our results unveil that the histotype-specific regulation of tumor fibrosis in lung cancer is mediated through differential SMAD3 promoter methylation in TAFs and provide new mechanistic insights on the selective poor response of SCC-TAFs to nintedanib. Moreover, our findings support that patients with ADC may be more responsive to antifibrotic drugs targeting their stromal TGFß1/SMAD3 activation. SIGNIFICANCE: This study implicates the selective epigenetic repression of SMAD3 in SCC-TAFs in the clinical failure of nintedanib in SCC and supports that patients with ADC may benefit from antifibrotic drugs targeting stromal TGFß1/SMAD3.

Occupation, smoking, and chronic obstructive respiratory disorders: a cross sectional study in an industrial area of Catalonia, Spain.

BACKGROUND: Few studies have investigated the independent effects of occupational exposures and smoking on chronic bronchitis and airflow obstruction. We assessed the association between lifetime occupational exposures and airflow obstruction in a cross-sectional survey in an urban-industrial area of Catalonia, Spain. METHODS: We interviewed 576 subjects of both sexes aged 20-70 years (response rate 80%) randomly selected from census rolls, using the ATS questionnaire. Forced spirometry was performed by 497 subjects according to ATS normative. RESULTS: Lifetime occupational exposure to dust, gases or fumes was reported by 52% of the subjects (63% in men, 41% in women). Textile industry was the most frequently reported job in relation to these exposures (39%). Chronic cough, expectoration and wheeze were more prevalent in exposed subjects with odds ratios ranging from 1.7 to 2.0 being highest among never-smokers (2.1 to 4.3). Lung function differences between exposed and unexposed subjects were dependent on duration of exposure, but not on smoking habits. Subjects exposed more than 15 years to dusts, gases or fumes had lower lung function values (FEV1 -80 ml, 95% confidence interval (CI) -186 to 26; MMEF -163 ml, CI -397 to 71; FEV1/FVC ratio -1.7%, CI -3.3 to -0.2) than non-exposed. CONCLUSION: Chronic bronchitis symptoms and airflow obstruction are associated with occupational exposures in a population with a high employment in the textile industry. Lung function impairment was related to the duration of occupational exposure, being independent of the effect of smoking.

Benefits of low weekly doses of methotrexate in steroid-dependent asthmatic patients. A double-blind, randomized, placebo-controlled study.

BACKGROUND: Though several drugs have been tested, the choice of the ideal steroid-sparing agent in steroid-dependent asthmatic patients remains unclear. Our objective was to evaluate the efficacy and tolerance of methotrexate in low weekly doses in order to decrease chronic oral steroid requirements in asthmatic patients. DESIGN: double blind randomized placebo-controlled study. SETTING: The study was performed in a 760-bed teaching hospital. PATIENTS: 46 steroid-dependent asthmatic patients were randomized. INTERVENTIONS: PATIENTS received 10mg of methotrexate or placebo once weekly for a year. The 6-methylprednisolone was progressively tapered (2mg/day every two weeks) until FEV1 diminished by 5% or more; 6-methylprednisolone was then increased until the previous FEV1 was reached, and the procedure was repeated throughout follow-up. MEASUREMENTS: Blood and urine analyses and bone densitometry were performed at entry and at the end of the study. Pulmonary function was tested monthly during the first three months and then every three months until the end. RESULTS: Thirty-nine patients were evaluated at interim analysis. A 54.8% decrease (9.5+/-4.9 mg/day) in 6-methylprednisolone dose was observed in the methotrexate group and a 4.4% decrease (0.5+/-7.2 mg/day) in the placebo group (P<0.001). There was no significant decrease of FEV1 in either group. No changes in bone metabolism were observed except for a non-statistically significant increase in osteocalcin levels in the treated group compared to a decrease in the placebo group. Toxicity was mild. CONCLUSIONS: (1) Methotrexate is an effective steroid-sparing agent. (2) A dosage lower than the one recommended in the literature is effective. (3) Tolerance is good. (4) No benefit or detrimental effects in bone metabolism were observed after one year.