Expressions of p53, cyclinD1 and histopathological features in basal cell carcinomas

Molecular Mechanisms and Targeted Therapies of Advanced Basal Cell Carcinoma

Among human cutaneous malignancies, basal cell carcinoma is the most common. Solid advances in unveiling the molecular mechanisms of basal cell carcinoma have emerged in recent years. In Gorlin syndrome, which shows basal cell carcinoma predisposition, identification of the patched 1 gene (PTCH1) mutation was a dramatic breakthrough in understanding the carcinogenesis of basal cell carcinoma. PTCH1 plays a role in the hedgehog pathway, and dysregulations of this pathway are known to be crucial for the carcinogenesis of many types of cancers including sporadic as well as hereditary basal cell carcinoma. In this review, we summarize the clinical features, pathological features and hedgehog pathway as applied in basal cell carcinoma. Other crucial molecules, such as p53 and melanocortin-1 receptor are also discussed. Due to recent advances, therapeutic strategies based on the precise molecular mechanisms of basal cell carcinoma are emerging. Target therapies and biomarkers are also discussed.

TERTp mutations and p53 expression in head and neck cutaneous basal cell carcinomas with different aggressive features

Cutaneous basal cell carcinoma (cBCC) is an economic burden to health services, due to its great morbidity and increasing incidence in old people. Infiltrative cBCCs and cBCCs with micronodular pattern are considered as more aggressive. The role of p53 expression and TERTp mutation on cBCC behavior remains to be clarified. We aimed to assess TERTp mutations and p53 expression in relation to the cBCC histological subtype in a cohort of patients referred to an ENT Department of a tertiary Hospital of Northern Portugal. We performed a retrospective clinicopathological and histological review of the head and neck cBCCs followed-up at the otorhinolaryngology department of Trás-os-Montes e Alto Douro hospital (January 2007–June 2018). We assessed TERTp mutations in 142 cBCCs and p53 protein expression, through immunohistochemistry, in 157 cBCCs. We detected TERTp mutations in 43.7% of cBCCs and p53 overexpression in 60.5% of cBCCs. We spotted association of p53 overexpression and TERTp mutation with necrosis. In the infitrative-growth pattern cBCCs, there was no significant association with the clinical and histological features evaluated, except for necrosis. In the indolent-growth cBCCs, we identified a significant association of TERTp mutation status with female sex, necrosis, multiple cBCCs, and p53 positive expression. Our results suggest that TERTp mutation may be useful to identify more aggressive features in the indolent-growth pattern cBCCs (nodular and superficial subtypes). Further studies with larger cohorts are warranted to clarify the relevance of TERTp mutation in cBCCs.

Transcription factorIRX5 promotes hepatocellular carcinoma proliferation and inhibits apoptosis by regulating the p53 signalling pathway

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third most frequent cause of cancer-related death. The IRX5 transcription factor plays a different role in multiple cancers and contributes to the development of many tumours. However, little is known about the molecular mechanisms of IRX5 in HCC. In this study, we found that IRX5 was abnormally upregulated in HCC tissues compared with adjacent normal tissues. IRX5 promoted HCC cell proliferation and upregulated the expression of cyclin D1 and knockdown of IRX5 suppressed tumorigenicity in vivo. Furthermore, knockdown of IRX5 increased p53 and Bax expression and decreased Bcl-2 expression. Thus, IRX5 suppressed apoptosis in HCC cells by inhibiting the p53 signalling pathway, indicating its role as a treatment target for HCC. SIGNIFICANCE OF THE STUDY: Our study demonstrated that IRX5 was abnormally upregulated in HCC tissues compared with adjacent normal tissues. IRX5 promoted HCC cell proliferation and upregulated the expression of cyclin D1, and knockdown of IRX5 suppressed tumorigenicity in vivo. Furthermore, knockdown of IRX5 increased p53 and Bax expression and decreased Bcl-2 expression. IRX5 suppressed apoptosis in HCC cells by inhibiting the p53 signalling pathway, indicating its role as a treatment target for HCC.

Chemoprotective Effects of Dietary Grape Powder on UVB Radiation-Mediated Skin Carcinogenesis in SKH-1 Hairless Mice

Skin cancer is the most frequently diagnosed cancer in the United States, and solar UVR is an established causative factor for approximately 90% of these cases. Despite efforts aimed at UV protection, including use of sunscreen and clothing, annual cases of skin cancer continue to rise. Here, we report that dietary grape powder mitigates UVB-mediated skin carcinogenesis in an SKH-1 hairless mouse model. Using a UVB initiation-promotion protocol, whereby mice were exposed to 180 mJ/cm² UVB two times per week for 28 weeks, we determined the effects of a grape powder-fortified diet (3% or 5%) on skin carcinogenesis. Grape powder consumption at both doses resulted in marked inhibition in tumor incidence, as well as a delay in onset of tumorigenesis. Molecular analyses of skin and tumor tissue showed that grape powder-mediated protective response against UVB-induced skin cancer was accompanied by enhanced DNA damage repair, reduced proliferation, increased apoptosis, and modulations in several oxidative stress markers specifically related to inhibition of oxidative stress and increased reactive oxygen species metabolism. NRF2, an activator of cellular antioxidant response, was decreased by grape powder feeding, suggesting a supportive role in tumor cell survival. Overall, our study suggested that dietary grape, containing several antioxidants in natural amalgamation, may protect against UVB-mediated skin carcinogenesis.

Genital basal cell carcinoma, a different pathogenesis from sun-exposed basal cell carcinoma? A case-control study of 30 cases

BACKGROUND

Genital basal cell carcinoma (BCC) accounts for <1% of all BCCs. We aimed to elucidate the pathogenesis of genital BCC.

METHODS

We retrospectively evaluated cases of pathologically diagnosed genital BCC between 1990 and 2016 in an Asian tertiary referral center. The control group was composed of consecutive cases, from 2016, of BCCs occurring in sun-exposed areas. Presence of human papillomavirus (HPV) was evaluated by polymerase chain reaction (PCR). Immunohistochemical p16 and p53 staining was performed and analyzed.

RESULTS

We found 33 genital BCCs (33/1837, 1.8%) over 26 years. The mean follow-up duration was 30.0 ± 33.2 months. Genital BCCs had a larger size (14.05 vs 8.92 mm, P = 0.014), more common presence of ulcers (61.3% vs 32.0%, P = 0.035), shorter epidermal p53 clone (0.33 vs 1.20 mm, P = 0.007), and high p53 expression levels. Most cases (29/30, 96.7%) showed negative or faint spotty p16 staining. Patient age, tumor depth, presence of pigment, or histology subtype did not differ significantly. Thirty genital BCCs were negative for HPV.

CONCLUSIONS

HPV infection is mostly likely not involved in genital BCC pathogenesis. A greater level of p53 expression in genital BCCs implicates pathways other than ultraviolet (UV)-specific p53 mutations in their pathogenesis.

Polarization and Distribution of Tumor-Associated Macrophages and COX-2 Expression in Basal Cell Carcinoma of the Ocular Adnexae

PURPOSE

Basal cell carcinoma (BCC) is a locally invasive skin tumor which can be subdivided into a circumscribed nodular and an invasive fibrosing subtype. There is increasing evidence that macrophages play an important role in interacting between tumor cells and their microenvironment, thereby affecting not only the invasive potential but also the patients' prognosis. Thus, we wanted to compare these two BCC variants with regard to tumor-related inflammation, COX-2 expression, distribution, and polarization of tumor-associated macrophages.

MATERIAL AND METHODS

30 BCCs (nodular: n = 15; fibrosing: n = 15) of the ocular adnexae were investigated by histopathology and immunohistochemistry. The grade of inflammation was evaluated on hematoxylin and eosin stains (score: 0-3). Immunohistochemical stains for CD68 (macrophages), Ki67 (proliferative activity), and COX-2 as well as immunofluorescence stains for CD68 and CD163 (to distinguish M1 and M2 macrophage subtypes) were performed. SPSS was used for statistical analysis.

RESULTS

Fibrosing BCCs were predominantly located on the lower lid, while nodular BCCs showed a broader distribution (p = 0.013). The fibrosing BCC subtype was associated with a higher degree of inflammation (p < 0.001) and revealed a higher COX-2 immunoreactivity than nodular BCC (p = 0.012). COX-2-positive cells were predominantly located on the infiltrating edge of the tumor. Macrophage polarization was balanced regarding M1 and M2 macrophage subtypes. There was no difference in macrophage number (p = 0.389) or polarization (p = 0.161) between nodular and fibrosing BCC.

CONCLUSIONS

The findings indicate that COX-2 represents a factor for invasion of BCC. Macrophage polarization did not play a major role for aggressive behavior. However, other inflammatory components than tumor-associated macrophages seem to be involved in tissue destruction and thereby an invading growth pattern since fibrosing BCC revealed a significantly more intense inflammatory reaction in the surrounding tissue.

ClC-3 Chloride Channel Proteins Regulate the Cell Cycle by Up-regulating cyclin D1-CDK4/6 through Suppressing p21/p27 Expression in Nasopharyngeal Carcinoma Cells

It was shown in this study that knockdown of ClC-3 expression by ClC-3 siRNA prevented the activation of hypotonicity-induced chloride currents, and arrested cells at the G0/G1 phase in nasopharyngeal carcinoma CNE-2Z cells. Reconstitution of ClC-3 expression with ClC-3 expression plasmids could rescue the cells from the cell cycle arrest caused by ClC-3 siRNA treatments. Transfection of cells with ClC-3 siRNA decreased the expression of cyclin D1, cyclin dependent kinase 4 and 6, and increased the expression of cyclin dependent kinase inhibitors (CDKIs), p21 and p27. Pretreatments of cells with p21 and p27 siRNAs depleted the inhibitory effects of ClC-3 siRNA on the expression of CDK4 and CDK6, but not on that of cyclin D1, indicating the requirement of p21 and p27 for the inhibitory effects of ClC-3 siRNA on CDK4 and CDK6 expression. ClC-3 siRNA inhibited cells to progress from the G1 phase to the S phase, but pretreatments of cells with p21 and p27 siRNAs abolished the inhibitory effects of ClC-3 siRNA on the cell cycle progress. Our data suggest that ClC-3 may regulate cell cycle transition between G0/G1 and S phases by up-regulation of the expression of CDK4 and CDK6 through suppression of p21 and p27 expression.

Polysaccharides from Capsosiphon fulvescens stimulate the growth of gastrointestinal cells

Capsosiphon fulvescens is a green alga that is abundant along the southwest coast of South Korea. Although it is consumed for its purported health-enhancing properties, particularly as a treatment for stomach disorders and hangovers, the health effects of dietary C. fulvescens remain unclear. Polysaccharides extracted from C. fulvescens (Cf-PS) are investigated for their effects on the proliferation of rat small intestinal epithelial IEC-6 cells. Cf-PS stimulated IEC-6 cell proliferation in a dose-dependent manner. Further, Cf-PS treatment induced the translocation of β-catenin, an effector of the Wnt signaling pathway, from the cytosol to the nucleus and increased the expression of cyclinD1 and c-myc. Cf-PS also induced ERK1/2 phosphorylation, which is activated by mitogenic and proliferative stimuli such as growth factors, but the phosphorylation of JNK and p38 was not enhanced. Therefore, this chapter discusses the effect of Cf-PS on the growth of gastrointestinal cells.

Polysaccharides from Capsosiphon fulvescens stimulate the growth of IEC-6 Cells by activating the MAPK signaling pathway

Seaweed extracts show diverse bioactivities, such as antioxidant and antitumor activity. Capsosiphon fulvescens is a green alga that is abundant along the southwest coast of South Korea. Although it is consumed for its purported health-enhancing properties, particularly as a treatment for stomach disorders and hangovers, the health effects of dietary C. fulvescens remain unclear. We extracted polysaccharides from C. fulvescens (Cf-PS), investigated their effects on the proliferation of rat small intestinal epithelial IEC-6 cells, and determined the signaling cascade involved. We cultured IEC-6 cells in the presence of Cf-PS, which stimulated cell proliferation in a dose-dependent manner, and analyzed the Wnt and MAPK signaling pathways, which are related to cell proliferation. Cf-PS treatment induced the translocation of β-catenin, an effector of the Wnt signaling pathway, from the cytosol to the nucleus and increased the expression of cyclinD1 and c-myc. Cf-PS also induced ERK1/2 phosphorylation, which is activated by mitogenic and proliferative stimuli such as growth factors, but the phosphorylation of JNK and p38 was not enhanced. Our results show that Cf-PS regulates proliferation via stimulating the nuclear translocation of β-catenin and ERK1/2 activation in intestinal epithelial cells.