Optimum modality for photodynamic therapy of tumors: gels containing liposomes with hydrophobic photosensitizers

Gel Formulations for Topical Treatment of Skin Cancer: A Review

Skin cancer, with all its variations, is the most common type of cancer worldwide. Chemotherapy by topical application is an attractive strategy because of the ease of application and non-invasiveness. At the same time, the delivery of antineoplastic agents through the skin is difficult because of their challenging physicochemical properties (solubility, ionization, molecular weight, melting point) and the barrier function of the stratum corneum. Various approaches have been applied in order to improve drug penetration, retention, and efficacy. This systematic review aims at identifying the most commonly used techniques for topical drug delivery by means of gel-based topical formulations in skin cancer treatment. The excipients used, the preparation approaches, and the methods characterizing gels are discussed in brief. The safety aspects are also highlighted. The combinatorial formulation of nanocarrier-loaded gels is also reviewed from the perspective of improving drug delivery characteristics. Some limitations and drawbacks in the identified strategies are also outlined and considered within the future scope of topical chemotherapy.

Enhanced expression of proproliferative and antiapoptotic genes in ulcerative colitis-associated neoplasia

BACKGROUND

Inflammatory bowel diseases including long-standing ulcerative colitis (UC) have an increased risk of evolving into colorectal cancer (CRC). The overexpression of some proproliferative and antiapoptotic genes, such as survivin, telomerase catalytic subunit (hTERT), integrin-linked kinase (ILK), and regulatory factors c-MYB and Tcf-4, has been implicated in the development and progression of several human malignancies including CRC.

METHODS

In this study we analyzed the expression alterations of these markers and proinflammatory enzymes cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) during the transition of colonic mucosa from chronic inflammation to epithelial neoplasia in biopsies of UC patients using quantitative real-time polymerase chain reaction and immunohistochemistry; additionally, we compared the expression profiles of this gene panel in samples of patients with CRC after tumor resection and in human tumor xenografts of SW620 malignant colonic cells.

RESULTS

The transcript levels of survivin, c-MYB, COX-2, iNOS, and Tcf-4 showed a statistically significant increase during neoplastic transformation of UC patient colonic mucosa, whereas hTERT and ILK were not elevated. In contrast, the specimens of CRC showed upregulated expression of not only survivin, c-MYB, Tcf-4, COX-2, and iNOS but also hTERT. A similar expression profile was observed in human tumor xenografts in which all transcripts with the exception of c-MYB were upregulated.

CONCLUSIONS

These results suggest that telomerase and ILK activation occurs during the later stages of carcinoma progression, whereas upregulation of survivin, c-MYB, and Tcf-4 is a feature of the early stage of development of neoplasia, and thus, they might serve as early indicators for UC-associated colorectal carcinogenesis.