Silibinin Treatment Inhibits the Growth of Hedgehog Inhibitor-Resistant Basal Cell Carcinoma Cells via Targeting EGFR-MAPK-Akt and Hedgehog Signaling

The mechanism of USP43 in the development of tumor: a literature review

Ubiquitination of the proteins is crucial for governing protein degradation and regulating fundamental cellular processes. Deubiquitinases (DUBs) have emerged as significant regulators of multiple pathways associated with cancer and other diseases, owing to their capacity to remove ubiquitin from target substrates and modulate signaling. Consequently, they represent potential therapeutic targets for cancer and other life-threatening conditions. USP43 belongs to the DUBs family involved in cancer development and progression. This review aims to provide a comprehensive overview of the existing scientific evidence implicating USP43 in cancer development. Additionally, it will investigate potential small-molecule inhibitors that target DUBs that may have the capability to function as anti-cancer medicines.

Quercetin ameliorates thioacetamide-induced hepatic fibrosis and oxidative stress by antagonizing the Hedgehog signaling pathway

The Hedgehog (Hh) pathway has emerged as a potential target for effectual hepatic repair based on convincing clinical and preclinical evidence that proves its significance in regulating hepatic damage. The purpose of this study is to probe the effect of quercetin on liver fibrosis through the modulation of the Hh pathway. Healthy male Wistar rats were divided into four groups (n = 10). The control group was treated with saline, rats in the remaining three groups received twice a week intoxication with intraperitoneal injections of thioacetamide (200 mg/kg) for the induction of hepatic fibrosis for 6 weeks. After 28 days of quercetin and silymarin treatment, histological changes, serum biochemical index, antioxidant enzyme activity, key mediators of Hh pathway and inflammation were analyzed. Serological analysis showed statistically improved cholesterol, H.D.L-Cholesterol, and L.D.L-Cholesterol in the treatment groups. Superoxide dismutase and glutathione levels were found to be increased after the treatment with quercetin and silymarin. mRNA expression of important mediators of the Hh signaling, and inflammation including Shh, Ihh, Ptch-1, Smo, Hhip, Gli-3, TNF-α, NFκ-β, and Socs-3 were significantly downregulated after the use of quercetin and silymarin. Quercetin also minimized the thioacetamide-induced histopathological changes, as confirmed by a lower degree of hepatic lobule degeneration, the intralobular occurrence of inflammatory cells, and a lower degree of hepatocytic necrosis. Sudan Black B staining showed remarked lipids improvements in the treatment groups. Taken together, these findings demonstrate that quercetin could ameliorate hepatic fibrosis by antagonizing the hedgehog pathway and also suggest the hedgehog pathway as a potential therapeutic target for the treatment of liver fibrosis.

Chemopreventive efficacy of silibinin against basal cell carcinoma growth and progression in UVB-irradiated Ptch+/- mice

The factors (environmental and genetic) contributing to basal cell carcinoma (BCC) pathogenesis are well-established; however, effective agents for BCC prevention are marred by toxic side-effects. Herein, we assessed the efficacy of flavonolignan silibinin against ultraviolet B (UVB)-induced BCC in Ptch+/- (heterozygous patched homolog 1 gene) mouse model. Both male and female Ptch+/- mice were irradiated with a 240 mJ/cm2 UVB dose 3 times/week for 26 or 46 weeks, with or without topical application of silibinin (9 mg/200 µl in acetone, applied 30 min before or after UVB exposure). Results indicated that silibinin application either pre- or post-UVB exposure for 26 weeks significantly decreased the number of BCC lesions by 65% and 39% (P < 0.001 for both) and the area covered by BCCs (72% and 45%, P < 0.001 for both), respectively, compared to UVB alone. Furthermore, continuous UVB exposure for 46 weeks increased the BCC lesion number and the BCC area covered by ~6 and ~3.4 folds (P < 0.001), respectively. Notably, even in this 46 week prolonged UVB exposure, silibinin (irrespective of pre- or post-UVB treatment) significantly halted the growth of BCCs by 81-94% (P < 0.001) as well as other epidermal lesions; specifically, silibinin treated tissues had less epidermal dysplasia, fibrosarcoma, and squamous cell carcinoma. Immunohistochemistry and immunofluorescence studies revealed that silibinin significantly decreased basal cell proliferation (Ki-67) and the expression of cytokeratins (14 and 15), and Hedgehog signaling mediators Smo and Gli1 in the BCC lesions. Together, our findings demonstrate strong potential of silibinin to be efficacious in preventing the growth and progression of UVB-induced BCC.

Wogonin inhibits the growth of HT144 melanoma via regulating hedgehog signaling-mediated inflammation and glycolysis

Hedgehog (Hh) signaling has been proved to be closely associated with the occurrence of melanoma. Wogonin is one of the active components of flavonoids that extracts from Scutellariae radix. Previous studies showed that wogonin could inhibit the invasion and migration of B16F10 cells, and suppress the synthesis of melanin in A375 melanoma cells. However, the regulatory effects of Hh signaling in wogonin against melanoma and its potential mechanisms remain largely unknown. The present study aimed to investigate the effect of wogonin on the growth of HT144 melanoma, and to elucidate the role of Hh signaling in wogonin-induced antitumor effects by focusing on inflammation and glycolysis regulation. Wogonin inhibited the proliferation, colony formation and tumor growth of HT144 melanoma cells. Wogonin showed strong anti-inflammatory effect in HT144 melanoma, as shown by the decreased levels of pro-inflammatory factors, the increased level of anti-inflammatory factor and the decreased expression of inflammatory cytokines. Wogonin decreased the glucose consumption and the production of lactic acid and ATP, and decreased the activities of hexokinase (HK), phosphofructokinase(PFK) and pyruvate kinase (PK), and further inhibited the expression of monocarboxylate transporter 1 (MCT-1), MCT-4 and glucosecotransporter-1 (GLUT1), showing potent anti-glycolysis effect against HT144 melanoma. Wogonin inhibited the patched and Smo expression while increased Hhip expression in HT144 cells, suggesting that wogonin blocked the Hh signaling in HT144 cells. The Hh signaling inhibitor cyclopamine, like wogonin, inhibited the colony formation of HT144 cells, however, the inhibitory effect of wogonin on colony formation of HT144 cells was abrogated by the Hh signaling agonist SAG. In addition, SAG abrogated the inhibitory effect of wogonin on the secretion of inflammatory factors and the expression of inflammatory cytokines. Furthermore, SAG abrogated the inhibitory effect of wogonin on several key molecules controlling glycolysis. Overall, these findings suggested that the anti-tumor effect of wogonin can be attributed to the inhibition of Hh signaling-mediated regulation of inflammation and glycolysis in HT144 melanoma.

Hedgehog Signaling: Implications in Cancers and Viral Infections

The hedgehog (SHH) signaling pathway is primarily involved in embryonic gut development, smooth muscle differentiation, cell proliferation, adult tissue homeostasis, tissue repair following injury, and tissue polarity during the development of vertebrate and invertebrate organisms. GLIoma-associated oncogene homolog (GLI) family of zinc-finger transcription factors and smoothened (SMO) are the signal transducers of the SHH pathway. Both SHH ligand-dependent and independent mechanisms activate GLI proteins. Various transcriptional mechanisms, posttranslational modifications (phosphorylation, ubiquitination, proteolytic processing, SUMOylation, and acetylation), and nuclear-cytoplasmic shuttling control the activity of SHH signaling pathway proteins. The dysregulated SHH pathway is associated with bone and soft tissue sarcomas, GLIomas, medulloblastomas, leukemias, and tumors of breast, lung, skin, prostate, brain, gastric, and pancreas. While extensively studied in development and sarcomas, GLI family proteins play an essential role in many host-pathogen interactions, including bacterial and viral infections and their associated cancers. Viruses hijack host GLI family transcription factors and their downstream signaling cascades to enhance the viral gene transcription required for replication and pathogenesis. In this review, we discuss a distinct role(s) of GLI proteins in the process of tumorigenesis and host-pathogen interactions in the context of viral infection-associated malignancies and cancers due to other causes. Here, we emphasize the potential of the Hedgehog (HH) pathway targeting as a potential anti-cancer therapeutic approach, which in the future could also be tested in infection-associated fatalities.

Path of Silibinin from diet to medicine: A dietary polyphenolic flavonoid having potential anti-cancer therapeutic significance

In the last few decades, targeting cancer by the use of dietary phytochemicals has gained enormous attention. The plausible reason and believe or mind set behind this fact is attributed to either lesser or no side effects of natural compounds as compared to the modern chemotherapeutics, or due to their conventional use as dietary components by mankind for thousands of years. Silibinin is a naturally derived polyphenol (a flavonolignans), possess following biochemical features; molecular formula C₂₅H₂₂O₁₀, Molar mass: 482.44 g/mol, Boiling point 793 °C, with strikingly high antioxidant and anti-tumorigenic properties. The anti-cancer properties of Silibinin are determined by a variety of cellular pathways which include induction of apoptosis, cell cycle arrest, inhibition of angiogenesis and metastasis. In addition, Silibinin controls modulation of the expression of aberrant miRNAs, inflammatory response, and synergism with existing anti-cancer drugs. Therefore, modulation of a vast array of cellular responses and homeostatic aspects makes Silibinin an attractive chemotherapeutic agent. However, like other polyphenols, the major hurdle to declare Silibinin a translational chemotherapeutic agent, is its lesser bioavailability. After summarizing the chemistry and metabolic aspects of Silibinin, this extensive review focuses on functional aspects governed by Silibinin in chemoprevention with an ultimate goal of summarizing the evidence supporting the chemopreventive potential of Silibinin and clinical trials that are currently ongoing, at a single platform.

Alternative Options for Skin Cancer Therapy via Regulation of AKT and Related Signaling Pathways

Global environmental pollution has led to human exposure to ultraviolet (UV) radiation due to the damaged ozone layer, thereby increasing the incidence and death rate of skin cancer including both melanoma and non-melanoma. Overexpression and activation of V-akt murine thymoma viral oncogene homolog (AKT, also known as protein kinase B) and related signaling pathways are major factors contributing to many cancers including lung cancer, esophageal squamous cell carcinoma and skin cancer. Although BRAF inhibitors are used to treat melanoma, further options are needed due to treatment resistance and poor efficacy. Depletion of AKT expression and activation, and related signaling cascades by its inhibitors, decreases the growth of skin cancer and metastasis. Here we have focused the effects of AKT and related signaling (PI3K/AKT/mTOR) pathways by regulators derived from plants and suggest the need for efficient treatment in skin cancer therapy.

Metastatic Basal Cell Carcinoma of the Skin: A Comprehensive Literature Review, Including Advances in Molecular Therapeutics

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. In Europe, the incidence of BCC ranges from 44.6 to 128 cases per 100,000 inhabitants annually, whereas in the United States, the yearly incidence rate ranges between 500 and 1500. The global incidence has been calculated to be as high as 10 million cases of BCC per year. There are 2 main clinical patterns of BCC-the familial BCC in basal cell nevus syndrome and sporadic BCC. The etiology of cutaneous BCC is usually the result of the interaction between solar ultraviolet radiation and genetic factors. Somatic or germline mutations in the effector components of the hedgehog signaling pathway (ie, PTCH1, PTCH2, SMO or SUFU genes) are responsible for ∼90% of the cases of both sporadic and familial BCC, all causing a constitutive activation of the hedgehog pathway. Cutaneous BCC very rarely metastasizes, and diagnosis in metastatic sites can be very difficult. Metastatic BCC has weakly effective therapeutic options with a poor prognosis until few years ago. In 2012, small-molecule therapies, involving inactivation of the hedgehog signaling pathway, and capable of reducing tumor growth and progression have been introduced into clinical practice for advanced (locally advanced or metastatic) BCC. We performed a comprehensive literature review on metastatic BCC and found at least 915 cases reported to date. In addition, we extensively discussed the differential diagnosis of metastatic BCC, and outlined the advances in clinical therapeutics involving these small molecules.

Silibinin and non-melanoma skin cancers

Skin is the largest human organ that shields the inner body from contact with xenobiotic and genotoxic agents, and in this process, the skin's cellular genome faces continuous stress due to direct exposure to these noxious factors. Accumulation of genetic stress results in genomic alterations leading to undesirable gene or protein alteration/expression in skin cells, which eventually causes the formation of non-melanoma skin cancers (NMSCs). Ultraviolet B (UVB) radiation from sun is the most prominent factor contributing to ∼5 million skin cancer cases (which are mostly NMSCs) in the United States (US) and western countries. UVB exposure causes aberrations in a range of biochemical and molecular pathways such as: thymine dimer formation, DNA damage, oxidative stress, inflammatory responses, altered cellular signaling, which ultimately contribute to the development of NMSCs. The focus of this review is to summarize the protective and preventive potential of silymarin and/or silibinin against UVB-induced NMSC in pre-clinical skin cancer studies. Over two decades of research has shown the strong potential of silibinin, a biologically active flavonolignan (crude form Silymarin) derived from milk thistle plant, against a wide range of cancers, including NMSCs. Silibinin protects against UVB-induced thymine dimer formation and in turn promotes DNA repair and/or initiates apoptosis in damaged cells via an increase in p53 levels. Additionally, silibinin has shown strong efficacy against NMSCs via its potential to target aberrant signaling pathways, and induction of anti-inflammatory responses. Overall, completed comprehensive studies suggest the potential use of silibinin to prevent and/or manage NMSCs in humans.

Silibinin inhibits epithelial‑mesenchymal transition of renal cell carcinoma through autophagy‑dependent Wnt/β‑catenin signaling

Silibinin is a flavonoid extracted from milk thistle seeds which has been widely used as a hepatoprotective and antioxidant agent. Recently, accumulating evidence has demonstrated the anti-cancer effects of silibinin in various cancer models. It was previously reported that silibinin induced apoptosis and decreased metastasis by activating autophagy in renal cell carcinoma (RCC). However, the underlying molecular mechanisms by which silibinin regulates autophagy remain largely unknown. The aim of the present study was to investigate the effects of silibinin on RCC metastasis in vitro and in vivo, with a focus on autophagy-dependent Wnt/β-catenin signaling. Human RCC 786-O and ACHN cell lines were used as the model system in vitro and RCC xenografts of nude mice were used for in vivo studies. Silibinin inhibited metastasis and epithelial-mesenchymal transition (EMT) of RCC in vitro and in vivo, by regulating the Wnt/β-catenin signaling pathway. Furthermore, silibinin inhibited the Wnt/β-catenin signaling pathway in an autophagy-dependent manner. Autophagic degradation of β-catenin induced by silibinin was associated with the anti-metastatic effects of silibinin against RCC. These findings identify a novel mechanism by which silibinin inhibits EMT and metastasis of RCC, highlighting a potential novel strategy for treating metastatic RCC.

Silibinin inhibits ultraviolet B radiation-induced mast cells recruitment and bone morphogenetic protein 2 expression in the skin at early stages in Ptch(+/-) mouse model of basal cell carcinoma

Around 80% of nonmelanoma skin cancers (NMSCs) are basal cell carcinoma (BCC), still studies evaluating the efficacy of chemopreventive agents during early stage/s of BCC development are lacking. Accordingly, utilizing the well-established patched (Ptch)+/- mouse model of ultraviolet B (UVB) radiation-induced BCC formation, we excised skin samples from UVB exposed Ptch+/- and Ptch+/+ mice before tumor formation to study the promotion/progression of BCC and to determine the efficacy and target/s of silibinin, a well-known skin cancer chemopreventive agent. UVB exposure for 1 month increased the number of mast cells in Ptch+/- mice by ~48% (P < 0.05), which was completely inhibited by silibinin. Polymerase chain reaction profiler array analysis of skin samples showed strong molecular differences between Ptch+/+ and Ptch+/- mice which were either unexposed or UVB irradiated+/- silibinin treatment. Most notably, silibinin treatment significant decreased the expression of BMP-2, Bbc3, PUMA, and Ccnd1 in Ptch+/- mice irradiated with silibinin + UVB. Additional studies showed that silibinin targets UVB-induced expression of bone morphogenetic protein 2 (BMP-2) in Ptch+/- mouse skin. Last, our studies found that silibinin strongly attenuates UVB-induced BMP-2 expression and DNA damage in Ptch+/- mouse skin ex vivo only after single UVB exposure. Together, our results suggest a possible role of mast cell recruitment and BMP-2 activation in the early stages of BCC development; these are strongly inhibited by silibinin suggesting its possible chemopreventive efficacy against BCC formation in long-term UVB exposure regimen.

Transactivated Epidermal Growth Factor Receptor Recruitment of α-actinin-4 From F-actin Contributes to Invasion of Brain Microvascular Endothelial Cells by Meningitic Escherichia coli

Bacterial penetration of the blood-brain barrier requires its successful invasion of brain microvascular endothelial cells (BMECs), and host actin cytoskeleton rearrangement in these cells is a key prerequisite for this process. We have reported previously that meningitic Escherichia coli can induce the activation of host's epidermal growth factor receptor (EGFR) to facilitate its invasion of BMECs. However, it is unknown how EGFR specifically functions during this invasion process. Here, we identified an important EGFR-interacting protein, α-actinin-4 (ACTN4), which is involved in maintaining and regulating the actin cytoskeleton. We observed that transactivated-EGFR competitively recruited ACTN4 from intracellular F-actin fibers to disrupt the cytoskeleton, thus facilitating bacterial invasion of BMECs. Strikingly, this mechanism operated not only for meningitic E. coli, but also for infections with Streptococcus suis, a Gram-positive meningitis-causing bacterial pathogen, thus revealing a common mechanism hijacked by these meningitic pathogens where EGFR competitively recruits ACTN4. Ever rising levels of antibiotic-resistant bacteria and the emergence of their extended-spectrum antimicrobial-resistant counterparts remind us that EGFR could act as an alternative non-antibiotic target to better prevent and control bacterial meningitis.

Review of Common Alternative Herbal "Remedies" for Skin Cancer

BACKGROUND

Alternative herbal remedies for skin cancer are commonly found on the Internet. Many websites contain inaccurate or false information regarding side effects and efficacy.

OBJECTIVE

To review the evidence behind several commonly advertised herbal remedies that claim to cure skin cancer: black salve, eggplant, frankincense, cannabis, black raspberry, milk thistle, St. John's wort, and turmeric.

METHODS

A PubMed search was performed using the common and scientific names of frequently advertised herbal remedies along with the terms "nonmelanoma skin cancer," or "basal cell carcinoma" or "squamous cell carcinoma," or "melanoma."

RESULTS

Some preclinical studies have shown positive evidence that these substances can induce apoptosis in skin cancer, but clinical studies proving efficacy are either insufficient, nonexistent, or show negative evidence. Botanicals that were excluded are those that do not have published studies of their efficacy as skin cancer treatments.

CONCLUSION

Online advertising may tempt patients to use botanical agents while citing efficacy found in preclinical studies. However, many agents lack strong clinical evidence of efficacy. Dermatologists must be aware of common herbal alternatives for skin cancer treatment to maintain effective patient communication and education.

Imbalance of the reciprocally inhibitory loop between the ubiquitin-specific protease USP43 and EGFR/PI3K/AKT drives breast carcinogenesis

Hyperactivation of EGFR/PI3K/AKT is a prominent feature of various human cancers. Thus, understanding how this molecular cascade is balanced is of great importance. We report here that the ubiquitin-specific protease USP43 is physically associated with the chromatin remodeling NuRD complex and catalyzes H2BK120 deubiquitination. Functionally this coordinates the NuRD complex to repress a cohort of genes, including EGFR, which are critically involved in cell proliferation and carcinogenesis. We show that USP43 strongly suppresses the growth and metastasis of breast cancer in vivo. Interestingly, USP43 also exists in the cytoplasm, where it is phosphorylated by AKT, enabling its binding to the 14-3-3β/ε heterodimer and sequestration in the cytoplasm. Significantly, hyperactivation of EGFR/PI3K/AKT in breast cancer is associated with the cytoplasmic retention of USP43 and thus, the inhibition of its transcriptional regulatory function. Moreover, cancer-associated mutations of USP43 affect its subcellular localization and/or epigenetic regulatory functions. Nuclear USP43 is significantly reduced in breast carcinomas and is associated with EGFR accumulation and AKT hyperactivation. A low level of nuclear USP43 correlates with higher histologic grades and poor prognosis. Our study identifies USP43 to be an H2BK120 deubiquitinase and a potential tumor suppressor and reveals a reciprocally inhibitory loop between USP43 and EGFR/PI3K/AKT, whose imbalance drives breast carcinogenesis.

Regulation of Hedgehog Signaling in Cancer by Natural and Dietary Compounds

The aberrant Hedgehog (Hh) signaling induced by mutations or overexpression of the signaling mediators has been implicated in cancer, associated with processes including inflammation, tumor cell growth, invasion, and metastasis, as well as cancer stemness. Small molecules targeting the regulatory components of the Hh signaling pathway, especially Smoothened (Smo), have been developed for the treatment of cancer. However, acquired resistance to a Smo inhibitor vismodegib observed in clinical trials suggests that other Hh signaling components need to be explored as potential anticancer targets. Natural and dietary compounds provide a resource for the development of potent agents affecting intracellular signaling cascades, and numerous studies have been conducted to evaluate the efficacy of natural products in targeting the Hh signaling pathway. In this review, we summarize the role of Hh signaling in tumorigenesis, discuss results from recent studies investigating the effect of natural products and dietary components on Hh signaling in cancer, and provide insight on novel small molecules as potential Hh signaling inhibitors.

Epigallocatechin-3-O-gallate alleviates the malignant phenotype in A-431 epidermoid and SK-BR-3 breast cancer cell lines

In this study, we evaluated the effects of epigallocatechin-3-O-gallate (EGCG) in two cancer cell lines, A-431 overexpressing ErbB1 and SK-BR-3, overexpressing ErbB2. EGCG treatment showed dose-dependent collapse of mitochondrial membrane potential (Δψ_m), increase in reactive oxygen species (ROS) production, changes in nuclear morphology and reduced viability. Flow cytometry data indicated that EGCG partially decreases the phosphorylation of several proteins involved in cell proliferation and survival: pErbB1(Y1173, Y1068), pAkt(S473) and pERK(Y204). EGCG affected the clonogenic growth in both cell lines with an EC₅₀ of 2.5 and 5.4 µM for A-431 and SK-BR-3, respectively. Wound scratch assay demonstrated that EGCG inhibited the healing in dose-dependent manner and the effect was correlated with partial reduction in phosphorylation of pFAK(S910). Our data suggest that EGCG administration might reduce the unfavourable traits, particularly associated with ErbB1/EGFR overexpression.