Therapeutic strategies and potential implications of silver nanoparticles in the management of skin cancer

Abstract

Skin cancer (SC) is the most common carcinoma affecting 3 million people annually in the United States and millions of people worldwide. It is classified as melanoma SC (MSC) and non-melanoma SC (NMSC). NMSC represents approximately 80% of SC and includes squamous cell carcinoma and basal cell carcinoma. MSC, however, has a higher mortality rate than SC because of its ability to metastasize. SC is a major health problem in the United States with significant morbidity and mortality in the Caucasian population. Treatment options for SC include cryotherapy, excisional surgery, Mohs surgery, curettage and electrodessication, radiation therapy, photodynamic therapy, immunotherapy, and chemotherapy. Treatment is chosen based on the type of SC and the potential for side effects. Novel targeted therapies are being used with increased frequency for large tumors and for metastatic disease. A scoping literature search on PubMed, Google Scholar, and Cancer Registry websites revealed that traditional chemotherapeutic drugs have little effect against SC after the cancer has metastasized. Following an overview of SC biology, epidemiology, and treatment options, this review focuses on the mechanisms of advanced technologies that use silver nanoparticles in SC treatment regimens.

Keywords: basal cell carcinoma; biology; clinical manifestations; epidemiology; malignant melanoma; silver nanoparticles; skin cancer; squamous cell carcinoma; treatment.

Figure 1:

The characteristic histology of different forms of skin cancer: basal cell carcinoma: (a) nodular masses of basaloid cells extend into the dermis with peritumoral stroma (4×); (b) closer magnification highlights the peripheral palisading and tumor retraction artifact (10×); squamous cell carcinoma: (c) scanning magnification highlights a crater-like tumor with irregular masses of atypical keratinocytes invading the dermis. A pronounced surrounding inflammatory infiltrate is seen (4×); (d-1) and (d-2) invading tumor masses with atypical keratinocytes, dyskeratotic cells, and keratin pearls (10×); melanoma: (e) scanning magnification reveals a broad, atypical melanocytic proliferation which is asymmetric and poorly circumscribed (4×); (f) the epidermal proliferation is characterized by variably sized nests at and above the dermoepidermal junction. A robust lymphocytic inflammatory response is present (10×); (g) closer magnification again reveals nests at and above the dermoepidermal junction. The lesional cells are atypical, and single melanocytes are noted at all levels of the epidermis in a pagetoid arrangement (20×) (photographs were provided by Dr. Allison Cruse, Department of Dermatology, University of Mississippi Medical Center, Jackson, Mississippi, USA).

Figure 2:

Interactions between Shh, Ptch-1, and Gli-1.

Figure 3:

Clinical manifestations of different forms of skin cancer: (a) malignant melanoma distant view; (b) superficial BCC; (c) nodular BCC; (d) melanoma; (e) malignant melanoma with regression; (f) SCC (photographs were provided by Robert T. Brodell, MD, Professor and Chair, Department of Dermatology, University of Mississippi Medical Center, Jackson, Mississippi, USA).

Figure 4:

Signaling pathway of AgNP-induced apoptosis.