Botanical agents for the treatment of nonmelanoma skin cancer

Glioblastoma targeting by water-soluble hypericin derivate HHL-PVP and photodynamic tumour killing

Hypericin, a tumour-selective photosensitizer, has shown potential in cancer therapy, but its poor water solubility has limited clinical use. To address this, we developed a water-soluble variant called high hypericin-loaded polyvinylpyrrolidone (HHL-PVP) to enhance hypericin's applicability, particularly for treating glioblastoma, a typically terminal disease. We tested HHL-PVP in both in vitro and in vivo models, first confirming its fluorescent properties in the lab and then assessing its efficacy in more complex animal models. Using subcutaneous and orthotopic tumour mouse models, we combined HHL-PVP administration with fluorescence-guided surgery and photodynamic therapy (PDT) to target residual tumour cells. Histological analysis of both healthy and tumour tissue showed HHL-PVP's over 97 % sensitivity and 100 % specificity in distinguishing tumour tissue. In subcutaneous glioblastoma models, significant tumour necrosis and remission occurred after HHL-PVP administration and a 20-minute white light application through the skin. These results highlight HHL-PVP's effectiveness in targeting and eradicating glioblastoma cells. Our findings provide strong evidence that HHL-PVP is a promising therapeutic option for glioblastoma, with its high sensitivity, specificity, and potential for tumour remission through PDT. This approach warrants further investigation in clinical trials and could improve outcomes for a disease that has been difficult to treat.

P53 and the Ultraviolet Radiation-Induced Skin Response: Finding the Light in the Darkness of Triggered Carcinogenesis

This review delves into the significant cellular and molecular responses triggered by UVR exposure in human skin, emphasizing the pivotal role of mutant p53 (mutp53) in the carcinogenic process elicited by radiation. By underlining the role of a functional p53 in safeguarding skin cells from UVR-induced damage, this work underscores the potential significance of targeting mutp53, aiming to restore its wild-type-like activity (reactivation), as a protective strategy against skin cancer (SC), particularly NMSC. Most importantly, an interesting crosstalk between p53 and its vitamin D receptor (VDR) transcriptional target is also highlighted in the suppression of skin carcinogenesis, which opens the way to promising chemopreventive strategies involving synergistic combinations between mutp53 reactivators and vitamin D. Collectively, this review not only opens new avenues for future research, but also offers promising prospects for the development of novel beneficial approaches in the field of SC.

Skin Cancer: An Insight on its Association with Aging, Pathogenesis and Treatment Strategies

Skin cancer is one of the deadly diseases of the skin characterized by pain and uncontrolled growth of cells. The pathogenesis of skin cancer involves the uncontrolled division of abnormal cells in the part of the body affected by an accumulation of genome variation over the course of a lifetime. The incidence of skin cancer has been increasing all over the world and has been reported more in old-aged persons. Furthermore, aging plays a vital role in promoting malignancy. Cancer necessitates lifelong administration of drugs to maintain the quality of life. The major challenge of treatment is the side effects associated with these drugs. Novel and targeted approaches are now formulated to explore as an alternative measure to treat cancer. The current review summarizes the pathogenesis of cancer and its treatment strategies. These approaches are discussed with regard to the drugs, mechanism of action, causative factors, distribution of cancer, mortality rate, and treatment strategies.

Skin cancer: understanding the journey of transformation from conventional to advanced treatment approaches

Skin cancer is a global threat to the healthcare system and is estimated to incline tremendously in the next 20 years, if not diagnosed at an early stage. Even though it is curable at an early stage, novel drug identification, clinical success, and drug resistance is another major challenge. To bridge the gap and bring effective treatment, it is important to understand the etiology of skin carcinoma, the mechanism of cell proliferation, factors affecting cell growth, and the mechanism of drug resistance. The current article focusses on understanding the structural diversity of skin cancers, treatments available till date including phytocompounds, chemotherapy, radiotherapy, photothermal therapy, surgery, combination therapy, molecular targets associated with cancer growth and metastasis, and special emphasis on nanotechnology-based approaches for downregulating the deleterious disease. A detailed analysis with respect to types of nanoparticles and their scope in overcoming multidrug resistance as well as associated clinical trials has been discussed.

Formulation, Characterization, Anti-Inflammatory and Cytotoxicity Study of Sesamol-Laden Nanosponges

Sesamol (SES) possesses remarkable chemotherapeutic activity, owing to its anti-inflammatory and antioxidant potential. However, the activity of SES is mainly hampered by its poor physicochemical properties and stability issues. Hence, to improve the efficacy of this natural anti-inflammatory and cytotoxic agent, it was loaded into β-cyclodextrin nanosponges (NS) prepared using different molar ratios of polymer and crosslinker (diphenyl carbonate). The particle size of SES-laden NS (SES-NS) was shown to be in the nano range (200 to 500 nm), with a low polydispersity index, an adequate charge (-17 to -26 mV), and a high payload. Field emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the bioactive-loaded selected batch (SES-NS6). This batch of nanoformulations showed improved solubilization efficacy (701.88 µg/mL) in comparison to bare SES (244.36 µg/mL), polymer (β-CD) (261.43 µg/mL), and other fabricated batches. The drug release data displayed the controlled release behavior of SES from NS. The findings of the egg albumin denaturation assay revealed the enhanced anti-inflammatory potential of SES-NS as compared to bare SES. Further, the cytotoxicity assay showed that SES-NS was more effective against B16F12 melanoma cell lines than the bioactive alone. The findings of this assay demonstrated a reduction in the IC₅₀ values of SES-NS (67.38 μg/mL) in comparison to SES (106 μg/mL). The present investigation demonstrated the in vitro controlled release pattern and the enhanced anti-inflammatory and cytotoxic activity of SES-NS, suggesting its potential as a promising drug delivery carrier for topical delivery.

Cathelicidin-NV from Nanorana ventripunctata effectively protects HaCaT cells, ameliorating ultraviolet B-induced skin photoaging

Cathelicidins are diverse effector molecules in the vertebrate immune system and are related to immune regulation, inflammatory response, wound healing, and blood vessel formation. However, little is known about their free radical scavenging ability, especially in vivo. In this study, a cathelicidin molecule (cathelicidin-NV, ARGKKECKDDRCRLLMKRGSFSYV) previously identified from the spot-bellied plateau frog (Nanorana ventripunctata) (Anura, Dicroglossidae, Dicroglossinae) by us was shown to alleviate ultraviolet B (UVB)-induced skin photoaging in mice. Cathelicidin-NV effectively suppressed cytotoxicity, DNA fragmentation, apoptosis and reduced the protein expression levels of JNK, c-Jun, and MMP-1, which are involved in the regulation of collagen degradation in HaCaT cells induced by UVB irradiation. Furthermore, cathelicidin-NV also scavenged UVB-induced intracellular reactive oxygen species (ROS). Taken together, cathelicidin-NV directly scavenged excessive intracellular ROS to protect HaCaT cells, and subsequently alleviated UVB-induced skin photoaging. This study extends reports on the antioxidant function of the cathelicidin family. In addition, the properties of cathelicidin-NV make it an excellent candidate for the prevention and treatment of UV-induced skin photoaging.

Regular Intake of Green Tea Polyphenols Suppresses the Development of Nonmelanoma Skin Cancer through miR-29-Mediated Epigenetic Modifications

Previously, we and others have shown that the regular intake of green tea polyphenols (GTPs) reduces ultraviolet B (UVB) radiation-induced skin cancer by targeting multiple signaling pathways, including DNA damage, DNA repair, immunosuppression, and inflammation. Here, we determine the effect of GTPs on UVB-induced epigenetic changes, emphasizing DNA hypermethylation in UV-exposed skin and tumors and their association with miR-29, a key regulator of DNA methyltransferases (DNMTs). Skin cancer was induced in SKH-1 hairless mice following repeated exposures of UVB radiation (180 mJ/cm², three times/week, 24 weeks) with or without GTPs supplementation (0.2%) in drinking water. Regular intake of GTPs inhibited tumor growth by hindering the cascade of DNA hypermethylation events. GTPs supplementation significantly blocked UVB-induced DNA hypermethylation in the skin (up to 35%; p < 0.0001) and in tumors (up to 50%; p < 0.0001). Experimental results showed that the levels of DNA hypermethylation were higher in GTPs-treated mice than in the control group. The expressions of miR-29a, miR-29b, and miR-29c were markedly decreased in UV-induced skin tumors, and GTPs administration blocked UVB-induced miR-29s depletion. Furthermore, these observations were verified using the in vitro approach in human skin cancer cells (A431) followed by treatment with GTPs or mimics of miR-29c. Increased levels of miR-29 were observed in GTPs-treated A431 cells, resulting in increased TET activity and decreased DNA hypermethylation. In conclusion, UVB-mediated miR-29 depletion promotes DNA hypermethylation and leads to enhanced tumor growth by silencing tumor suppressors. Regular intake of GTPs rescued UVB-induced miR-29 depletion and prevented tumor growth by maintaining reduced DNA hypermethylation and activating tumor suppressors. Our observations suggest that miR-based strategies and regular consumption of GTPs could minimize the risk of UVB-induced skin cancers and contribute to better management of NMSCs.

Augmented Therapeutic Efficacy of Naringenin Through Microemulsion-Loaded Sericin Gel Against UVB-Induced Photoaging

Naringenin (NAR) is a flavonoid found in citrus fruits such as grapes and oranges. Recently, NAR has demonstrated its potential in inhibition of photoaging. The aim of the present study was to investigate the efficacy of sericin (SR) gel loaded with NAR microemulsion (ME) to inhibit UVB-induced photoaging and prevention of epidermoid carcinoma in animal model. NAR -ME was prepared and optimized through Box-Behnken design. The optimized ME was loaded into sericin (SR) gel. The formulations were subjected to various in vitro, in vivo and cytotoxicity studies over A431 cell lines. The optimized ME revealed a globule size of 249.05 ± 3.78 nm, 6.7 ± 0.5 pH and 73.1 ± 2.11% release over a period of 24 h respectively. Cytotoxicity studies revealed a depression in IC₅₀ value in NAR -ME (65.11 ± 1.54 μg/ml) when compared with NAR (118.1 ± 2.09 μg/ml). The NAR-ME-SR gel displayed enhanced therapeutic potential when compared with plain NAR, in terms of augmented antiproliferative activity. Graphical abstract.

Colloidal (-)-epigallocatechin-3-gallate vesicular systems for prevention and treatment of skin cancer: A comprehensive experimental study with preclinical investigation

Skin carcinogenesis is a common malignancy affecting humans worldwide, which could benefit from nutraceuticals as a solution to the drawbacks of conventional skin cancer treatment. (-)-epigallocatechin-3-gallate (EGCG) is a promising nutraceutical in this regard; however, it suffers chemical instability and low bioavailability resulting in inefficient delivery. Therefore, EGCG encapsulation in ultradeformable colloidal vesicular systems, namely: penetration enhancer-containing vesicles (PEVs), ethosomes and transethosomes (TEs) for topical administration has been attempted in this study to overcome the problems associated with the use of free EGCG. The prepared vesicles were characterized for their entrapment efficiency, TEM visualization, chemical compatibility, antioxidant properties, ex-vivo skin deposition, photodegradation and physical stability after storage. Most of the prepared vesicles exhibited reasonable skin deposition and preservation of the inherent antioxidant properties of EGCG with good physical stability. EGCG-loaded PEVs and TEs exhibited an inhibitory effect on epidermoid carcinoma cell line (A431) in addition to reduced tumor sizes in mice, confirmed with histopathological analysis and biochemical quantification of skin oxidative stress biomarkers; glutathione, superoxide dismutase and catalase, as well as lipid peroxidation. EGCG PEVs succeeded in offering an effective delivery system targeting skin cancer, which is worthy of further experimentation.

Histone deacetylase inhibitors potentiate photodynamic therapy in colon cancer cells marked by chromatin-mediated epigenetic regulation of CDKN1A

BACKGROUND

Hypericin-mediated photodynamic therapy (HY-PDT) has recently captured increased attention as an alternative minimally invasive anticancer treatment, although cancer cells may acquire resistance. Therefore, combination treatments may be necessary to enhance HY-PDT efficacy. Histone deacetylase inhibitors (HDACis) are often used in combination treatments due to their non-genotoxic properties and epigenetic potential to sensitize cells to external stimuli. Therefore, this study attempts for the first time to investigate the therapeutic effects of HDACis in combination with visible light-mediated PDT against cancer. Specifically, the colorectal cancer cell model was used due to its known resistance to HY-PDT.

RESULTS

Two chemical groups of HDACis were tested in combination with HY-PDT: the hydroxamic acids Saha and Trichostatin A, and the short-chain fatty acids valproic acid and sodium phenylbutyrate (NaPB), as inhibitors of all-class versus nuclear HDACs, respectively. The selected HDACis manifest a favorable clinical toxicity profile and showed similar potencies and mechanisms in intragroup comparisons but different biological effects in intergroup analyses. HDACi combination with HY-PDT significantly attenuated cancer cell resistance to treatment and caused the two HDACi groups to become similarly potent. However, the short-chain fatty acids, in combination with HY-PDT, showed increased selectivity towards inhibition of HDACs versus other key epigenetic enzymes, and NaPB induced the strongest expression of the otherwise silenced tumor suppressor CDKN1A, a hallmark gene for HDACi-mediated chromatin modulation. Epigenetic regulation of CDKN1A by NaPB was associated with histone acetylation at enhancer and promoter elements rather than histone or DNA methylation at those or other regulatory regions of this gene. Moreover, NaPB, compared to the other HDACis, caused milder effects on global histone acetylation, suggesting a more specific effect on CDKN1A chromatin architecture relative to global chromatin structure. The mechanism of NaPB + HY-PDT was P53-dependent and likely driven by the HY-PDT rather than the NaPB constituent.

CONCLUSIONS

Our results show that HDACis potentiate the antitumor efficacy of HY-PDT in colorectal cancer cells, overcoming their resistance to this drug and epigenetically reactivating the expression of CDKN1A. Besides their therapeutic potential, hypericin and these HDACis are non-genotoxic constituents of dietary agents, hence, represent interesting targets for investigating mechanisms of dietary-based cancer prevention.

Mechanisms of Photoaging and Cutaneous Photocarcinogenesis, and Photoprotective Strategies with Phytochemicals

Photoaging and photocarcinogenesis are primarily due to solar ultraviolet (UV) radiation, which alters DNA, cellular antioxidant balance, signal transduction pathways, immunology, and the extracellular matrix (ECM). The DNA alterations include UV radiation induced thymine-thymine dimers and loss of tumor suppressor gene p53. UV radiation reduces cellular antioxidant status by generating reactive oxygen species (ROS), and the resultant oxidative stress alters signal transduction pathways such as the mitogen-activated protein kinase (MAPK), the nuclear factor-kappa beta (NF-κB)/p65, the janus kinase (JAK), signal transduction and activation of transcription (STAT) and the nuclear factor erythroid 2-related factor 2 (Nrf2). UV radiation induces pro-inflammatory genes and causes immunosuppression by depleting the number and activity of the epidermal Langerhans cells. Further, UV radiation remodels the ECM by increasing matrixmetalloproteinases (MMP) and reducing structural collagen and elastin. The photoprotective strategies to prevent/treat photoaging and photocarcinogenesis include oral or topical agents that act as sunscreens or counteract the effects of UV radiation on DNA, cellular antioxidant balance, signal transduction pathways, immunology and the ECM. Many of these agents are phytochemical derivatives and include polyphenols and non-polyphenols. The flavonoids are polyphenols and include catechins, isoflavones, proanthocyanidins, and anthocyanins, whereas the non-flavonoids comprise mono phenolic acids and stilbenes. The natural sources of polyphenols include tea, cocoa, grape/wine, soy, pomegranate, and Polypodium leucotomos. The non-phenolic phytochemicals include carotenoids, caffeine and sulphoraphance (SFN). In addition, there are other phytochemical derivatives or whole extracts such as baicalin, flavangenol, raspberry extract, and Photomorphe umbellata with photoprotective activity against UVB radiation, and thereby carcinogenesis.

Modulation of viability and apoptosis of UVB-exposed human keratinocyte HaCaT cells by aqueous methanol extract of laver (Porphyra yezoensis)

We investigated the effect of 80% methanol extract of laver (Porphyra yezoensis) on the UVB-exposed HaCaT cells, human keratinocytes. The laver extract showed absorbance spectrum characteristic of porphyra-334 or shinorine, major mycosporine-like amino acids (MAAs) in red algae, and contained phenolic compounds. UVB exposure decreased cell viability and increased apoptotic cell fractions, and it also decreased the ratio of reduced (GSH) to oxidized glutathione (GSSG) and the total glutathione content. Post-treatment with the laver extract significantly increased the net viability and also the apoptotic cell fractions of UVB-exposed cells. The extract caused increase in GSH/GSSG ratio, yet it exacerbated the decrease in glutathione content in the UVB-exposed cells. These effects of the laver extract were also manifested in the sham-exposed cells, suggesting that those effects might be general phenomena caused by the laver extract. The extract treatment enhanced the UVB-induced phosphorylation of JNK and ERK, affecting more the latter. Our results suggest that the post-treatment with laver extract may protect UVB-exposed skin cells not only by increasing overall cell proliferation but also by enhancing apoptosis of damaged cells, via activating JNK and ERK signaling pathways, in which modulation of the content and redox status of glutathione may take significant parts.