Fig. 4.
Characterization of the HSP response to MWCNT-mediated photothermal therapy. Tumors that had been either untreated, treated with 30 sec of NIR laser alone, or treated with the combination of MWCNT plus laser were serially sectioned, and HSP expression was detected by immunofluorescent staining as described in Materials and Methods. (A) The top row of images depicts basal level of expression of HSP27, HSP70, and HSP90 in an untreated tumor. The middle two rows of images depict HSP expression in tumor sections taken at increasing tissue depths in a tumor treated with laser alone. Induction of HSPs proximate to the skin surface after 30 sec of NIR laser exposure is consistent with the superficial heating detected by MR thermometry (see Fig. 3). The lower two rows of images depict HSP expression in tumor sections taken at increasing tissue depths in a tumor treated with the combination of MWCNT plus laser. Thermoablative temperatures reached with the combination of MWCNTS and 30 sec of NIR laser exposure prevent HSP induction at the tumor surface. (B) HSP levels were quantified as described in Materials and Methods and expressed relative to untreated tumors (HSP expression in untreated tumors was the same throughout the tumor). Due to changes in tissue size imposed by processing, distances from the surface are presented as relative units: 1 is closest to the tumor surface (indicated as “surface” in A) and 4 is furthest from the surface (labeled “tumor base” in A). Means and standard deviations of 3 replicate 5-μm sections from 5 independently treated tumors in each group are shown.