Etiologies of Melanoma Development and Prevention Measures: A Review of the Current Evidence

A multicenter case-control study comparing sun exposure habits and use of photoprotection measures in patients diagnosed with different types of skin cancer

BACKGROUND

While skin cancer awareness programs have significantly furthered public understanding about the harmful effects of the sun, there is a disparity between photoprotection knowledge and protection practices.

OBJECTIVE

To compare sun exposure habits and photoprotection measures in patients diagnosed with basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma versus controls.

METHODS

Multicentre case-control observational study carried out by 13 Spanish dermatologists between April 2020 and August 2022. Patients diagnosed with BCC, SCC, or melanoma were considered cases. The control group consisted of individuals with no history of skin cancer.

RESULTS

Of the 254 cases (56.2% female; mean age, 62.67 ± 15.65), 119 (31.2%) had BCC, 62 (16.27%) SCC, and 73 (19.1%) melanoma. The control group consisted of 127 (33.33%) individuals. Avoiding sun exposure between 12:00 and 16:00 was the most commonly used photoprotection measure (habitually/always: 63.1%), followed by the use of sunscreen (habitually/always: 58.9%). Patients with melanoma were less likely to use clothing and shade to avoid sun exposure (p < .05), whereas those with BCC and SCC reported greater use of head coverings (p = .01). BCC and SCC groups reported greater sun exposure 15 years prior, whereas controls reported greater use of sunscreen. However, at the time of this study all groups reported using SPF ≥ 21, and the majority SPF > 50. No differences were observed in photoprotection measures between people with and without a previous history of skin cancer.

CONCLUSIONS

We describe differences in photoprotection measures and sun exposure patterns among patients diagnosed with different skin tumor types. Whether these differences may influence the type of tumor each developed will require further investigation.

The effect of sulindac on redox homeostasis and apoptosis-related proteins in melanotic and amelanotic cells

BACKGROUND

Non-steroidal anti-inflammatory drugs have been shown to inhibit the development of induced neoplasms. Our previous research demonstrated that the cytotoxicity of sulindac against melanoma cells is comparable to dacarbazine, the drug used in chemotherapy. The aim of this study was to investigate the mechanism of sulindac cytotoxicity on COLO 829 and C32 cell lines.

METHODS

The influence of sundilac on the activity of selected enzymes of the antioxidant system (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) and the content of hydrogen peroxide as well as the level of proteins initiating (p53, Bax) and inhibiting (Bcl-2) apoptosis were measured in melanoma cells.

RESULTS

In melanotic melanoma cells, sulindac increased the activity of SOD and the content of H2O2 but decreased the activity of CAT and GPx. The level of p53 and Bax proteins rose but the content of Bcl-2 protein was lowered. Similar results were observed for dacarbazine. In amelanotic melanoma cells, sulindac did not cause an increase in the activity of measured enzymes or any significant changes in the level of apoptotic proteins.

CONCLUSION

The cytotoxic effect of sulindac in the COLO 829 cell line is connected to disturbed redox homeostasis by changing the activity of SOD, CAT, GPx, and level of H2O2. Sulindac also induces apoptosis by changing the ratio of the pro-apoptotic/anti-apoptotic protein. The presented studies indicate the possibility of developing target therapy against melanotic melanoma using sulindac.

Clinical, Dermoscopic, and Histological Characteristics of Melanoma Patients According to the Age Groups: A Retrospective Observational Study

BACKGROUND

Although the role of melanoma risk factors is well documented, their correlation with patients' age is less frequently analyzed.

METHOD

The analysis was performed among 189 melanoma patients in different age groups, including <30 years, 31-60 years, and >60 years, to investigate the risk factors, topography, and coexistence of morphological features of 209 melanomas (dermoscopic and histopathological).

RESULTS

Among the youngest age group, no correlation with the presence of estimated risk factors was found. The most common dermoscopic pattern was spitzoid and multicomponent asymmetric. The group of middle-aged patients was the most diverse in terms of the occurrence of risk factors, solar lentiginosis, dermoscopic patterns, topography, histological subtypes, and invasiveness of melanomas. The oldest group characterized a strong correlation between solar lentiginosis, NMSC comorbidity, the prevalence of facial melanomas, the dermoscopic pattern of melanoma arising on chronic sun-damaged skin, and regression.

CONCLUSION

The findings regarding the presence of age-specific features in melanoma patients, especially in the youngest and middle-aged groups, might be helpful for clinicians and to target secondary prevention efforts.

Binding of the B-Raf Inhibitors Dabrafenib and Vemurafenib to Human Serum Albumin: A Biophysical and Molecular Simulation Study

Drug binding to human serum albumin (HSA) significantly affects in vivo drug transport and biological activity. To gain insight into the binding mechanism of the two B-Raf tyrosine kinase inhibitors dabrafenib and vemurafenib to HSA, in this work, we adopted a combined strategy based on fluorescence spectroscopy, isothermal titration calorimetry (ITC), circular dichroism (CD), and molecular simulations. Both anticancer drugs are found to bind spontaneously and with a 1:1 stoichiometry within the same binding pocket, located in Sudlow's site II (subdomain IIIA) of the protein with comparable affinity and without substantially perturbing the protein secondary structure. However, the nature of each drug-protein interactions is distinct: whereas the formation of the dabrafenib/HSA complex is more entropically driven, the formation of the alternative vemurafenib/HSA assembly is prevalently enthalpic in nature. Kinetic analysis also indicates that the association rate is similar for the two drugs, whereas the residence time of vemurafenib within the HSA binding pocket is somewhat higher than that determined for the alternative B-Raf inhibitor.

The Anticancer Potential of Doxycycline and Minocycline-A Comparative Study on Amelanotic Melanoma Cell Lines

Malignant melanoma is still a serious medical problem. Relatively high mortality, a still-growing number of newly diagnosed cases, and insufficiently effective methods of therapy necessitate melanoma research. Tetracyclines are compounds with pleiotropic pharmacological properties. Previously published studies on melanotic melanoma cells ascertained that minocycline and doxycycline exerted an anti-melanoma effect. The purpose of the study was to assess the anti-melanoma potential and mechanisms of action of minocycline and doxycycline using A375 and C32 human amelanotic melanoma cell lines. The obtained results indicate that the tested drugs inhibited proliferation, decreased cell viability, and induced apoptosis in amelanotic melanoma cells. The treatment caused changes in the cell cycle profile and decreased the intracellular level of reduced thiols and mitochondrial membrane potential. The exposure of A375 and C32 cells to minocycline and doxycycline triggered the release of cytochrome c and activated initiator and effector caspases. The anti-melanoma effect of analyzed drugs appeared to be related to the up-regulation of ERK1/2 and MITF. Moreover, it was noticed that minocycline and doxycycline increased the level of LC3A/B, an autophagy marker, in A375 cells. In summary, the study showed the pleiotropic anti-cancer action of minocycline and doxycycline against amelanotic melanoma cells. Considering all results, it could be concluded that doxycycline was a more potent drug than minocycline.