Chemopreventive effect of 4'-demethyl epipodophyllotoxin on DMBA/TPA-induced mouse skin carcinogenesis

Dhawan, Deepika; Balasubramanian, S.; Amonkar, A.J.; Singh, Neeta

doi:10.1093/carcin/20.6.997

Cited by 34 publications

(26 citation statements)

References 22 publications

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“…Also the invasive growth of keratin inward, into the epidermis was observed in skin tumors of this group. These results are supported by previous findings that DMBA/TPA treatment results in necrotic keratinized pearls, suggesting invasive squamous cell carcinoma (26). Whereas in DMBA/TPA+ LAM treatment (group III), the extent of lesions was less as compared to group II.…”

Section: Discussionsupporting

confidence: 90%

“…The reduction in body weights can be attributed to the initiation of carcinogenesis induced by DMBA/TPA, which might be a result of metabolic changes. Similarly, decrease in average body weight in the conditions of DMBAinduced squamous cell carcinoma of skin (26,28). However supplementation of LA and LAM to DMBA/TPA treated mice did not show any significant change when compared with DMBA/TPA treated mice.…”

Section: Discussionmentioning

confidence: 85%

“…They modulate gene expression by epigenetic mechanism [25]. Topical application of 12-Otetradecanoylphorbol-13-acetate (TPA) has been reported to increased release of ROS and hence may play an intermediate role in the induction of tumor promotion related genes [26].…”

Section: Introductionmentioning

confidence: 99%

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Antitumor Activity of Lantadenes in DMBA/TPA Induced Skin Tumors in Mice: Expression of Transcription Factors

Kaur¹,

Sharma

Sharma³

et al. 2010

Am. J. Biomed. Sci.

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Various triterpenoids extracted from plants have been shown as chemopreventive agents in cancer. Lantadene A (22β-angeoloxyloxy-3-oxoolean-12-en-28-oic acid; LA) is a pentacyclic triterpenoid, isolated from a weed Lantana camara L. and semisynthetically modified to its methyl ester (Methyl22β-angeoloxyloxy-3-oxoolean-12-en-28-oate; LAM) were used for the present studies. LA and LAM were studied for its chemopreventive effect on 7, 12-dimethylbenz[a]anthracene (DMBA) followed by 12-Otetradecanoylphorbol-13-acetate (TPA) induced squamous cell carcinoma in Swiss albino mice. The skin lesions were induced by the twice-weekly topical application of DMBA (100nmol/100µl of acetone) for two weeks followed by TPA (1.7nmol/100µl of acetone) on the depilated back of mice. LA and LAM were administered orally at a dose of 50mg/kg body weight twice a week, one week before the topical application of DMBA and continued 20 weeks thereafter. Histopathology of tumors was evaluated in all treatment groups. Previous studies in authors laboratory revealed a significant decrease in incidence and average number of papillomas in mice as compared to DMBA/TPA alone at the end of study. Transcription factors; activator protein-1 (AP-1; c-jun and c-fos), Nuclear factor-kappa B (NF-κB; p65) and p53 were evaluated by using RT-PCR. A significant decrease in the mRNA expression of AP-1 (c-jun and c-fos), NF-kB (p-65) and p53 was observed in LAM and LA treated mice skin tumors. These findings were supported by histopathological studies. From the results, it can be inferred that LAM and LA possesses potential chemopreventive activity and may be linked to the expression of transcription factors.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 85%

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Antitumor Activity of Lantadenes in DMBA/TPA Induced Skin Tumors in Mice: Expression of Transcription Factors

Kaur¹,

Sharma

Sharma³

et al. 2010

Am. J. Biomed. Sci.

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“…Pretreatment with glycyrrhizin and subsequent exposure of mice with TPA led to significant increase in the above antioxidant enzymes. This might have been possible because GST, GR and GPx are secondary oxidant enzymes which might have helped in the detoxification of reactive oxygen species by decreasing the peroxide level or by maintaining a steady supply of glutathione [31]. Considering the importance of oxidative damage in carcinogenesis, induction of the detoxification of enzymes by naturally occurring or synthetic agents represents a promising strategy for cancer prevention [32].…”

Section: Discussionmentioning

confidence: 99%

Glycyrrhizin exhibits potential chemopreventive activity on 12-O-tetradecanoyl phorbol-13-acetate-induced cutaneous oxidative stress and tumor promotion in swiss albino mice

Rahman¹,

Sultana²

2007

Journal of Enzyme Inhibition and Medicinal Chemistry

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“…ROS have been suggested as causative factors in mutagenesis, carcinogenesis and tumor promotion and have been implicated in the etiology and pathophysiology of many human diseases [21]. They induce strand breaks and cause oxidative modification of DNA bases [22].…”

Section: Discussionmentioning

confidence: 99%

Prior exposure to restraint stress enhances 7,12‐dimethylbenz(a)anthracene (DMBA) induced DNA damage in rats

2006

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Over the years, several lines of evidence have emerged supporting the role of stress in the development and progression of cancer. Stress can cause an increase in the production of reactive oxygen species (ROS) and decrease in the in vivo antioxidant defense systems. A ROS-induced DNA damage in peripheral lymphocytes, liver and skin cells may be revealed by Comet assay. To test whether DNA is damaged by stress/ DMBA/stress and DMBA, rats were exposed to multiple doses of DMBA in the presence and absence of restraint stress, and DNA damage was evaluated. Insignificant differences were detected in all the three cells tested (peripheral lymphocytes, liver and skin cells) between control and stress treatment in terms of frequencies of damaged DNA. The extent of DNA migration was enhanced in DMBA treated rats in a dose dependent manner. Pre-stress DMBA treatment showed still higher frequencies of damage in comparison with control, stress alone or DMBA alone groups. Thus, prior exposure to stress clearly enhanced the DMBA induced DNA damage, especially so in the skin cells (target organ of the carcinogen application) than liver and peripheral lymphocytes as observed on the basis of the extent of DNA migration (tail DNA) during single cell gel electrophoresis.

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Chemopreventive effect of 4'-demethyl epipodophyllotoxin on DMBA/TPA-induced mouse skin carcinogenesis

Cited by 34 publications

References 22 publications

Antitumor Activity of Lantadenes in DMBA/TPA Induced Skin Tumors in Mice: Expression of Transcription Factors

Antitumor Activity of Lantadenes in DMBA/TPA Induced Skin Tumors in Mice: Expression of Transcription Factors

Glycyrrhizin exhibits potential chemopreventive activity on 12-O-tetradecanoyl phorbol-13-acetate-induced cutaneous oxidative stress and tumor promotion in swiss albino mice

Prior exposure to restraint stress enhances 7,12‐dimethylbenz(a)anthracene (DMBA) induced DNA damage in rats

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