Immunohistochemical analysis of the mechanistic target of rapamycin and hypoxia signalling pathways in basal cell carcinoma and trichoepithelioma

Exploring Nanocarriers as Treatment Modalities for Skin Cancer

Cancer is a progressive disease of multi-factorial origin that has risen worldwide, probably due to changes in lifestyle, food intake, and environmental changes as some of the reasons. Skin cancer can be classified into melanomas from melanocytes and nonmelanoma skin cancer (NMSC) from the epidermally-derived cell. Together it constitutes about 95% of skin cancer. Basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (CSCC) are creditworthy of 99% of NMSC due to the limited accessibility of conventional formulations in skin cancer cells of having multiple obstacles in treatment reply to this therapeutic regime. Despite this, it often encounters erratic bioavailability and absorption to the target. Nanoparticles developed through nanotechnology platforms could be the better topical skin cancer therapy option. To improve the topical delivery, the nano-sized delivery system is appropriate as it fuses with the cutaneous layer and fluidized membrane; thus, the deeper penetration of therapeutics could be possible to reach the target spot. This review briefly outlooks the various nanoparticle preparations, i.e., liposomes, niosomes, ethosomes, transferosomes, transethosomes, nanoemulsions, and nanoparticles technologies tested into skin cancer and impede their progress tend to concentrate in the skin layers. Nanocarriers have proved that they can considerably boost medication bioavailability, lowering the frequency of dosage and reducing the toxicity associated with high doses of the medication.

Hypoxia in Skin Cancer: Molecular Basis and Clinical Implications

Skin cancer is one of the most prevalent cancers in the Caucasian population. In the United States, it is estimated that at least one in five people will develop skin cancer in their lifetime, leading to significant morbidity and a healthcare burden. Skin cancer mainly arises from cells in the epidermal layer of the skin, where oxygen is scarce. There are three main types of skin cancer: malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Accumulating evidence has revealed a critical role for hypoxia in the development and progression of these dermatologic malignancies. In this review, we discuss the role of hypoxia in treating and reconstructing skin cancers. We will summarize the molecular basis of hypoxia signaling pathways in relation to the major genetic variations of skin cancer.

Trichoepithelioma presenting as leonine facies in a young female

Trichoepithelioma is a rare benign tumour of the pilosebaceous unit that originates from the hair follicles. Although it rarely results in facial disfigurement, it is thought to be the cause of leonine facies. We discuss a 27-year-old woman who presented with facies Leonine caused by trichoepitheliomas. The first line of treatment for these multiple symmetrical, firm, and round papules or nodules is excisional surgery.

Development and optimization of transethosomal gel of apigenin for topical delivery: In-vitro, ex-vivo and cell line assessment

The main aim of this study was to optimize the transethosomes of apigenin formulated by the thin film hydration method using surfactant Span 80. Response surface Box-Behnken design with three levels of three factors was used to design and optimize the formulations. The prepared transethosomal formulations were characterized for entrapment efficiency, vesicle size, and flux to obtain the optimized formulation batch. The optimized batch was further incorporated into the gel and characterized for the in-vitro, ex-vivo, and cytotoxic studies. The result showed the optimized transethosomes were smooth, nanosized, unilamellar, and spherical with an entrapment efficiency of 78.75 ± 3.14 %, a vesicle size of 108.75 ± 2.31 nm, and a flux of 4.10 ± 0.63 µg/cm²/h. In-vitro cumulative drug release of transethosomal gel of apigenin (TEL gel) and the conventional gel was 92.25 ± 3.5 % and 53.40 ± 3.10 %, respectively, after 24 h study. Ex-vivo permeation of TEL gel and conventional gel showed 86.20 ± 3.60 % and 51.20 ± 3.20 % permeation of apigenin at 24 h, respectively. A cytotoxic study confirmed that TEL gel significantly reduces cell viability compared to conventional gel. The results suggested that topical application of apigenin transethosomal gel may be a better treatment strategy for skin cancer because of the prolonged sustained release of the drug and the better permeability of apigenin through the skin.

The regulation of skin homeostasis, repair and the pathogenesis of skin diseases by spatiotemporal activation of epidermal mTOR signaling

The epidermis, the outmost layer of the skin, is a stratified squamous epithelium that protects the body from the external world. The epidermis and its appendages need constantly renew themselves and replace the damaged tissues caused by environmental assaults. The mechanistic target of rapamycin (mTOR) signaling is a central controller of cell growth and metabolism that plays a critical role in development, homeostasis and diseases. Recent findings suggest that mTOR signaling is activated in a spatiotemporal and context-dependent manner in the epidermis, coordinating diverse skin homeostatic processes. Dysregulation of mTOR signaling underlies the pathogenesis of skin diseases, including psoriasis and skin cancer. In this review, we discuss the role of epidermal mTOR signaling activity and function in skin, with a focus on skin barrier formation, hair regeneration, wound repair, as well as skin pathological disorders. We propose that fine-tuned control of mTOR signaling is essential for epidermal structural and functional integrity.

Recent Updates on the Involvement of PI3K/AKT/mTOR Molecular Cascade in the Pathogenesis of Hyperproliferative Skin Disorders

PhosphoInositide-3 Kinase (PI3K) represents a family of different classes of kinases which control multiple biological processes in mammalian cells, such as cell growth, proliferation, and survival. Class IA PI3Ks, the main regulators of proliferative signals, consists of a catalytic subunit (α, β, δ) that binds p85 regulatory subunit and mediates activation of AKT and mammalian Target Of Rapamycin (mTOR) pathways and regulation of downstream effectors. Dysregulation of PI3K/AKT/mTOR pathway in skin contributes to several pathological conditions characterized by uncontrolled proliferation, including skin cancers, psoriasis, and atopic dermatitis (AD). Among cutaneous cancers, basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) display PI3K/AKT/mTOR signaling hyperactivation, implicated in hyperproliferation, and tumorigenesis, as well as in resistance to apoptosis. Upregulation of mTOR signaling proteins has also been reported in psoriasis, in association with enhanced proliferation, defective keratinocyte differentiation, senescence-like growth arrest, and resistance to apoptosis, accounting for major parts of the overall disease phenotypes. On the contrary, PI3K/AKT/mTOR role in AD is less characterized, even though recent evidence demonstrates the relevant function for mTOR pathway in the regulation of epidermal barrier formation and stratification. In this review, we provide the most recent updates on the role and function of PI3K/AKT/mTOR molecular axis in the pathogenesis of different hyperproliferative skin disorders, and highlights on the current status of preclinical and clinical studies on PI3K-targeted therapies.

Development of Novel 18F-PET Agents for Tumor Hypoxia Imaging

Tumor hypoxia is a major factor responsible for tumor progression, metastasis, invasion, and treatment resistance, leading to low local tumor control and recurrence after radiotherapy in cancers. Here,¹⁸F-positron emission tomography (PET) probes are developed for visualizing viable hypoxic cells in biopsies. Pimonidazole derivatives and nitroimidazole-based agents bearing sulfonyl linkers were evaluated. A small-animal PET study showed that the tumor uptake of [¹⁸F]-23 [poly(ethylene glycols) (PEG)-sulfonyl linker] of 3.36 ± 0.29%ID/g was significantly higher (P < 0.01) than that of [¹⁸F]-20 (piperazine-linker tracer, 2.55 ± 0.49%ID/g) at 2 h postinjection in UPPL tumors. The tumor-to-muscle uptake ratio of [¹⁸F]-23 (2.46 ± 0.48 at 2 h pi) was well improved compared with that of [¹⁸F]-FMISO (1.25 ± 0.14 at 2 h pi). A comparable distribution pattern was observed between ex vivo autoradiography of [¹⁸F]-23 and pimonidazole staining of the neighboring slice, indicating that [¹⁸F]-23 is a promising PET agent for hypoxia imaging.

Management of multiple trichoepithelioma: A review of pharmacological therapies

Trichoepithelioma is a rare benign adnexal neoplasm that can occur in various forms including solitary, multiple, familial or nonfamilial. Multiple facial trichoepithelioma can be associated with significant psychosocial burden. Conventional treatment modalities such as surgical excision and ablative laser have variable results and can be associated with unacceptable complications and tumour regrowth. Pharmacological interventions such as topical and systemic agents are potentially effective but clinical data are limited and treatments are poorly standardised. We review the available evidence to determine the role of pharmacological therapies in the management of multiple trichoepithelioma. Demographic and clinical data were retrospectively collected from the available English literature. Majority of cases treated with pharmacological therapies (93.75%) had a positive treatment outcome, achieving partial lesion response. Adverse effects associated with pharmacological therapies were generally well tolerated and did not interrupt treatment. There are limitations as to how our results can be interpreted owing to the paucity of good quality evidence, spectrum of disease severity, and diversity of study designs utilised in the included articles. Nonetheless, the results of our study indicate that while most pharmacological interventions for multiple trichoepithelioma produce a partial response, they can be employed as effective suppressive therapies, either alone or in conjunction with conventional treatments. The current evidence for pharmacological therapies remains largely anecdotal justifying the need for further clinical studies in this area.

mTOR in Lung Neoplasms

With the discovery of rapamycin 45 years ago, studies in the mechanistic target of rapamycin (mTOR) field started 2 decades before the identification of the mTOR kinase. Over the years, studies revealed that the mTOR signaling is a master regulator of homeostasis and integrates a variety of environmental signals to regulate cell growth, proliferation, and metabolism. Deregulation of mTOR signaling, particularly hyperactivation, frequently occurs in human tumors. Recent advances in molecular profiling have identified mutations or amplification of certain genes coding proteins involved in the mTOR pathway (eg, PIK3CA, PTEN, STK11, and RICTOR) as the most common reasons contributing to mTOR hyperactivation. These genetic alterations of the mTOR pathway are frequently observed in lung neoplasms and may serve as a target for personalized therapy. mTOR inhibitor monotherapy has met limited clinical success so far; however, rational drug combinations are promising to improve efficacy and overcome acquired resistance. A better understanding of mTOR signaling may have the potential to help translation of mTOR pathway inhibitors into the clinical setting.

Novel NBQ-48 as marker of hypoxic cells in 2D and 3D colon cancer cells

This study presents the applicability of a novel nitro-substituted heterocyclic compound NBQ48, member of the family of compounds identified as 3 nitrobenzazolo[3, 2-a] quinolinium chloride salts (NBQS) as a screening tool to identify hypoxic tumor cells. The applicability was tested on COLO 205 colon cancer cells 2D and 3D cultures treated with NBQ48 to assess the formation of a bio-reduction fluorescent metabolite under hypoxic conditions in contrast, to those under aerobic environment. Hypoxic environment was created applying a controlled hypoxic gas chamber. Prior to testing the applicability of NBQ48 as a hypoxic fluorescent marker, cytotoxic studies where performed to identify a low-toxicity dose at 24 hours under aerobic and hypoxic environments that would allow the bio-reduction process with little toxicity. The differences in fluorescence emission after treatment was measured by fluorometer and fluorescence microscopy. Results indicated that cell treatments up to 24 hours with NBQ48 under aerobic environment did not reach an IC50 dose in COLO205 cells, however under hypoxic environment the IC50 reached at 100μM. The significant fluorescence increment after 24 and 48 hrs in 2D and 3D cultures treated with NBQ48 (75uM) at hypoxic in contrast to aerobic environments clearly demonstrated the need of a low oxygen content for the bio-reduction of the parent NBQ48. This study confirms the applicability of NBQ48 as markers for hypoxia in metabolically active 2D and 3D cultures. This hydrophilic hypoxic marker could additionally aid researchers in testing hypoxia activated pro-drugs for therapeutic applications in cancer as well as on other diseases where cellular hypoxia is a significant risk factor.

SOX9 Transcriptionally Regulates mTOR-Induced Proliferation of Basal Cell Carcinomas

Currently available smoothened targeted therapies in patients with basal cell nevus syndrome are associated with substantial tumor recurrence and clinical resistance. Strategies bypassing smoothened and/or identifying additional downstream components of the Hedgehog pathway could provide novel antitumor targets with a better therapeutic index. Sry-related high mobility group box 9 (SOX9) is a Hedgehog/glioma-associated oncogene homolog-regulated transcription factor known to be overexpressed in basal cell carcinomas (BCCs). A sequence motif search for SOX9-responsive elements identified three motifs in the promoter region of mammalian target of rapamycin (mTOR). In murine BCC cells, SOX9 occupies the mTOR promoter and induces its transcriptional activity. Short hairpin RNA (shRNA)-mediated knockdown of SOX9, as well as smoothened inhibition by itraconazole and vismodegib, reduces mTOR expression and the phosphorylation of known downstream mTOR targets. These effects culminate in diminishing the proliferative capacity of BCC cells, demonstrating a direct mechanistic link between the Hedgehog and mTOR pathways capable of driving BCC growth. Furthermore, rapamycin, a pharmacologic mTOR inhibitor, suppressed the growth of UV-induced BCCs in Ptch1^+/-/SKH-1 mice, a model that closely mimics the accelerated BCC growth pattern of patients with basal cell nevus syndrome. Our data demonstrate that Hedgehog signaling converges on mTOR via SOX9, and highlight the SOX9-mTOR axis as a viable additional target downstream of smoothened that could enhance tumor elimination in patients with BCC.

[Analysis of BNIP3 expression and clinical research in salivary adenoid cystic carcinoma]

OBJECTIVE

This study investigated the expression of BNIP3 in salivary adenoid cystic carcinoma (SACC) and its correlations to the clinicopathological features and prognosis of patients with SACC. The role of BNIP3 in the progress of hypoxia-induced autophagy was elucidated.

METHODS

The expression levels of BNIP3, hypoxia inducible factor (HIF)-1α, and LC3 in 65 SACC cases were detected by immunohistochemical staining method, and the correlation between the expression of BNIP3 and the clinicopathological features in SACC was analyzed. In addition, the correlations of BNIP3 gene expression with HIF-1α and LC3 gene expression were analyzed. The survival rate of patients with SACC was evaluated by univa-riate survival analysis.

RESULTS

BNIP3 was considerably expressed in SACC in all three histological patterns, and was positive in 41 cases (63.1%). BNIP3 gene expression was significantly correlated with histological grade (P=0.001) and HIF-1α gene expression (P=0.011). By contrast, BNIP3 gene expression was not significantly correlated with LC3 gene expression (P=
0.167). The overall survival rate of patients with negative BNIP3 expression was better than that of patients with positive BNIP3 expression (P<0.05).

CONCLUSIONS

BNIP3 might play a vital role in the tumorigenesis of SACC and may be a new target for gene therapy.
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