Cleomycin A2

Bleomycin is a clinically potent anticancer drug used for the treatment of germ-cell tumors, lymphomas and squamous-cell carcinomas. Unfortunately, the therapeutic efficacy of bleomycin is severely hampered by the development of pulmonary fibrosis. However, the mechanisms underlying bleomycin-induced pulmonary fibrosis, particularly the molecular target of bleomycin, remains unknown. Here, using a chemical proteomics approach, we identify ANXA2 (annexin A2) as a direct binding target of bleomycin. The interaction of bleomycin with ANXA2 was corroborated both in vitro and in vivo. Genetic depletion of anxa2 in mice mitigates bleomycin-induced pulmonary fibrosis. We further demonstrate that Glu139 (E139) of ANXA2 is required for bleomycin binding in lung epithelial cells. A CRISPR-Cas9-engineered ANXA2E139A mutation in lung epithelial cells ablates bleomycin binding and activates TFEB (transcription factor EB), a master regulator of macroautophagy/autophagy, resulting in substantial acceleration of autophagic flux. Pharmacological activation of TFEB elevates bleomycin-initiated autophagic flux, inhibits apoptosis and proliferation of epithelial cells, and ameliorates pulmonary fibrosis in bleomycin-treated mice. Notably, we observe lowered TFEB and LC3B levels in human pulmonary fibrosis tissues compared to normal controls, suggesting a critical role of TFEB-mediated autophagy in pulmonary fibrosis. Collectively, our data demonstrate that ANXA2 is a specific bleomycin target, and bleomycin binding with ANXA2 impedes TFEB-induced autophagic flux, leading to induction of pulmonary fibrosis. Our findings provide insight into the mechanisms of bleomycin-induced fibrosis and may facilitate development of optimized bleomycin therapeutics devoid of lung toxicity.

Background: Foam sclerotherapy is an effective treatment strategy for venous malformations. Both polidocanol (POL) and bleomycin are effective sclerosants; however, no studies have reported POL-bleomycin foam. Objective: To introduce a method for producing POL-bleomycin foam and evaluate the stability of POL-bleomycin foam with bleomycin concentrations. Materials and methods: Group A: 2 mL of 1% POL + 8 mL of air; Group B: 2 mL of 1% POL + 3 U bleomycin + 8 mL of air; Group C: 2 mL of 1% POL + 6 U bleomycin + 8 mL of air; Group D: 2 mL of 1% POL + 12 U bleomycin + 8 mL of air. Tessari method was used for foam generation. The foam half-life time (FHT) was used to evaluate foam stability. Five recordings were made for each group. Results: The FHT was 148.6 ± 2.9 seconds in Group A, 148.8 ± 4.0 seconds in Group B, 148.4 ± 2.6 seconds in Group C, and 148.8 ± 1.6 seconds in Group D. The FHT in different groups showed no significant differences. Conclusion: The POL-bleomycin foam was prepared successfully and its FHT was as long as the POL foam.

Background: Vascular malformations are congenital anomalies of the vascular system. Intralesional bleomycin injections are commonly used to treat vascular malformations. However, pulmonary fibrosis could potentially be a severe complication, known from systemic bleomycin therapy for malignancies. In this study, the authors investigate the effectiveness and safety of bleomycin (A2, B2, and A5) injections for vascular malformations, when possible relative to other sclerosants. Methods: The authors performed a PubMed, Embase, Cochrane Central Register of Controlled Trials, and gray literature search for studies (1995 to the present) reporting outcome of intralesional bleomycin injections in patients with vascular malformations (n ≥ 10). Predefined outcome measures of interest were size reduction, symptom relief, quality of life, adverse events (including pulmonary fibrosis), and patient satisfaction. Results: Twenty-seven studies enrolling 1325 patients were included. Quality of evidence was generally low. Good to excellent size reduction was reported in 84 percent of lymphatic and 87 percent of venous malformations. Pulmonary fibrosis was never encountered. Meta-analysis of four studies on venous malformations treated with bleomycin versus other sclerosants showed similar size reduction (OR, 0.67; 95 percent CI, 0.24 to 1.88) but a significantly lower adverse event rate (OR, 0.1; 95 percent CI, 0.03 to 0.39) and fewer severe complications after bleomycin. Symptom relief, quality of life, and patient satisfaction were reported inadequately. Conclusions: The authors' data suggest that bleomycin is effective in reducing the size of lymphatic and venous malformations, and leads to a lower adverse event rate and fewer severe complications than other sclerosants. The included literature does not provide evidence that pulmonary fibrosis is a complication of intralesional bleomycin injections. This study represents the "best available" evidence; however, only low- to moderate-quality studies were available. Clinical question/level of evidence: Therapeutic, IV.