In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: These findings demonstrate that overexpression of p300 protects cardiac myocytes from doxorubicin - induced apoptosis and reduces the extent of acute heart failure in adult mice in vivo .
### Output Text:
These findings demonstrate that overexpression of p300 protects cardiac myocytes from <span class="chemical">doxorubicin</span> - induced apoptosis and reduces the extent of acute heart failure in adult mice in vivo . 