1. MSc Thesis Project (Skin Cancer)
Mechanistic Studies on the effect of Nisin and Doxorubicin in a DMBA – Induced Skin Cancer
Model (Cell Lines)
Currently working on: In view of the emergence of multidrug-resistant cancer cells,
there is a need for therapeutic alternatives. Keeping this in mind, the present study was
aimed at evaluating the synergism between nisin (an antimicrobial peptide) and doxorubicin
against DMBA-induced skin carcinogenesis. The synergy was evaluated in terms of animal
bioassay observations, changes in hisotological architecture of skin tissues and in situ
apoptosis assay (TUNEL assay). Moreover, the possible tumoricidal activity of the
combination in terms of oxidant and antioxidant status of the skin tissues was also
evaluated by measuring lipid peroxidation levels, generation of nitrite, superoxide
dismutase and catalase activity. In vivo synergy was evidenced by larger decreases in mean
tumor burden, tumor volume and tumor multiplicity in mice treated with the combination
than those treated with the drugs alone. Histological observations indicated that nisin +
doxorubicin therapy causes chromatin condensation and marginalisation of nuclear material
in skin tissues of treated mice which correlated well with the results of TUNEL assay wherein
a marked increase in the rate of apoptosis was revealed in tissues treated with the
combination. An increased oxidative stress in response to the adjunct therapy was revealed
by significantly higher levels of lipid peroxidation (LPO) and nitrite generation in skin tissues
exposed to the adjunct therapy. An enhancement in superoxide dismutase levels
corresponding with a decrease in catalase activity was also observed in the skin tissue of
nisin, dox and nisin + dox treated groups as compared to tumor groups. These results point
toward the possible use of nisin as an adjunct to doxorubicin may help in developing
alternate strategies to combat currently developing drug resistance in cancer cells.
By Navjot Saini
Panjab University Chandigarh