Azadirachta indica Modulates Electrical Properties and Type of Cell Death in NDEA-Induced Hepatic Tumors

Electrical conductivity spectra of hepatic tumors reflect hepatocellular carcinoma progression in mice

Background:Electrical impedance spectroscopy is a technique which evaluates differences in dielectric properties of tissues for cancer identification.Methods:Murine hepatic cancer model was developed by intraperitoneal administration of N-nitrosodiethylamine to male BALB/c mice. Tumors obtained were evaluated for their conductivity in frequency range of (4 Hz-5 MHz). All tumors were subjected to histopathological grading and parameters such as free spacing, necrosis, and cell density were estimated on histological slides. The status of gap junctions and gap junction intercellular communication (GJIC) were studied using enzyme-linked immunosorbent assay, immunohistochemistry, dye transfer assay, and electron microscopy.Results:Histopathological investigation revealed the presence of moderately to poorly-differentiated hepatocellular carcinoma (HCC) in mice. All types of tumors showed higher electrical conductivity than normal liver tissue in frequency range (4 Hz-1 kHz). However, in frequency range (10 kHz-5 MHz) only poorly-differentiated tumors showed higher conductivity compared to normal tissue. The most prominent findings in moderately-differentiated and poorly-differentiated HCC were increased visible free spaces and necrosis respectively. The status of cell gap junctions were significantly deteriorated in tumors and a corresponding significant reduction in GJIC was also observed. These biological indicators were correlated with electrical conductivity of hepatic tumors.Conclusion:Variations in electrical conductivity spectra of hepatic tumors reflect progression of HCC.General significance:Future studies can be planned to perform hierarchical clustering of dielectric parameters with more number of tumor samples to establish dielectric spectroscopy-based classification or staging of hepatic tumors.

Mito-TEMPO, a mitochondria-targeted antioxidant, prevents N-nitrosodiethylamine-induced hepatocarcinogenesis in mice

BACKGROUND

Oxidative stress and mitochondrial dysfunction play a significant role in hepatocarcinogenesis. Mitochondria are source organelle as well as target for free radicals. The oxidative damage to mitochondria can be prevented by mitochondria-targeted antioxidant, mito-TEMPO. However, its efficacy in prevention of hepatocellular carcinoma has not been investigated so far.

METHODS

Murine model of hepatocarcinogenesis was developed by intraperitoneal administration of N-nitrosodiethylamine to male BALB/c mice. Mito-TEMPO was administered intraperitoneally at weekly intervals, till the completion of the study. The tumours were histopathologically analysed and anti-cancer efficacy of mito-TEMPO was evaluated in terms of survival index, tumour incidence, tumour multiplicity and tumour dielectric parameters. The antioxidant defence status and molecular composition of tumours were assessed. Gap junctions and gap-junctional intercellular communication (GJIC) were studied using ELISA, IHC and Lucifer yellow assay.

RESULTS

Mito-TEMPO treatment increased survival of animals by 30%, decreased tumour incidence (25%) and tumour multiplicity (39%). The dielectric parameters of tumours in Mito-TEMPO group were indicative of retarded carcinogenesis. Mito-TEMPO administration normalized mean saturation levels in phospholipids and improved glycogen content of the hepatic tissue. Gap junctions and GJIC which were severely impaired in hepatocarcinogenesis, improved after mito-TEMPO treatment.

CONCLUSION

Mito-TEMPO was effective in combating hepatocarcinogenesis.

Effect of nisin and doxorubicin on DMBA-induced skin carcinogenesis--a possible adjunct therapy

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 (DOX) against DMBA-induced skin carcinogenesis. The possible tumoricidal activity of the combination was evaluated in terms of animal bioassay observations, changes in hisotological architecture of skin tissues, in situ apoptosis assay (TUNEL assay) and in terms of oxidant and antioxidant status of the skin tissues. In vivo additive effect of the combination was evidenced by larger decreases in mean tumour burden and tumour volume in mice treated with the combination than those treated with the drugs alone. Histological observations indicated that nisin-DOX 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. A slightly increased oxidative stress in response to the adjunct therapy as compared to dox-alone-treated group was revealed by levels of lipid peroxidation (LPO) and nitrite generation in skin tissue-treated mice. An almost similar marginal enhancement in superoxide dismutase levels corresponding with a decrease in catalase activity could also be observed in nisin + DOX-treated groups as compared to nisin and dox-alone-treated groups. These results point towards 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.