SOX9 Transcriptionally Regulates mTOR-Induced Proliferation of Basal Cell Carcinomas

Assessment of Mammalian Target of Rapamycin Pathway Activation in Basal Cell Carcinoma as a New Therapeutic Approach

ABSTRACT

Targeting the mammalian target of rapamycin (mTOR) pathway represents a potentially novel approach to treat basal cell carcinoma (BCC), but activation of this pathway has not been well described in human BCCs. The purpose of this study was to assess whether mTOR pathway activation occurs in BCCs (both sporadic and syndromic) and report a case of a patient with Gorlin syndrome (GS) whose clinically suspicious BCCs responded to mTOR inhibition through topical sirolimus treatment. After Stanford Institutional Review Board Approval, archived BCCs from patients with GS (n = 25), sporadic BCCs (n = 35), and control tissues were subjected to immunohistochemical analysis for the activation of mTOR pathway, and immunohistochemical staining intensity was evaluated by a dermatopathologist. BCCs (compared with normal skin) had elevated levels of eIF4EBP1 ( Padjusted = 0.0336), which is downstream of mTOR. a serine/threonine kinase Phospho-(AKT), which interacts with mTOR, was also significantly elevated (perinuclear: Padjusted < 0.0001; cytoplasmic: Padjusted = 0.0021). When off-label topical 1% sirolimus was used on a pediatric patient with GS, we noted reduction of new BCC development and decreased size of existing neoplasms clinically suspicious for BCCs. This treatment was well tolerated after 2 years of continuous use, with no other treatments needed during this period. Topical sirolimus is a promising therapeutic candidate against both sporadic and GS-associated BCC. Multicenter, prospective studies are needed to understand the efficacy and safety of topical mTOR inhibitors in BCC treatment, and ascertain whether the immunohistochemical markers downstream of mTOR could have predictive value in identifying BCCs most likely to respond to topical mTOR inhibitors, such as sirolimus.

LT and SOX9 expression are associated with gene sets that distinguish Merkel cell polyomavirus (MCPyV)-positive and MCPyV-negative Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive malignant neuroendocrine tumour. There are two subsets of MCC, one related to Merkel cell polyomavirus (MCPyV) and the other to ultraviolet radiation (UVR). MCPyV-positive and MCPyV-negative MCCs have been considered to be different tumours, as the former harbour few DNA mutations and are not related to UVR, and the latter usually arise in sun-exposed areas and may be found in conjunction with other keratinocytic tumours, mostly squamous cell carcinomas. Two viral oncoproteins, large T antigen (LT; coded by MCPyV_gp3) and small T antigen (sT; coded by MCPyV_gp4), promote different carcinogenic pathways.

OBJECTIVES

To determine which genes are differentially expressed in MCPyV-positive and MCPyV-negative MCC; to describe the mutational burden and the most frequently mutated genes in both MCC subtypes; and to identify the clinical and molecular factors that may be related to patient survival.

METHODS

Ninety-two patients with a diagnosis of MCC were identified from the medical databases of participating centres. To study gene expression, a customized panel of 172 genes was developed. Gene expression profiling was performed with nCounter technology. For mutational studies, a customized panel of 26 genes was designed. Somatic single nucleotide variants (SNVs) were identified following the GATK Best Practices workflow for somatic mutations.

RESULTS

The expression of LT enabled the series to be divided into two groups (LT positive, n = 55; LT negative, n = 37). Genes differentially expressed in LT-negative patients were related to epithelial differentiation, especially SOX9, or proliferation and the cell cycle (MYC, CDK6), among others. Congruently, LT displayed lower expression in SOX9-positive patients, and differentially expressed genes in SOX9-positive patients were related to epithelial/squamous differentiation. In LT-positive patients, the mean SNV frequency was 4.3; in LT-negative patients it was 10 (P = 0.03). On multivariate survival analysis, the expression of SNAI1 [hazard ratio (HR) 1.046, 95% confidence interval (CI) 1.007-1.086; P = 0.02] and CDK6 (HR 1.049, 95% CI 1.020-1.080; P = 0.001) were identified as risk factors.

CONCLUSIONS

Tumours with weak LT expression tend to co-express genes related to squamous differentiation and the cell cycle, and to have a higher mutational burden. These findings are congruent with those of earlier studies.

Itraconazole halts hepatocellular carcinoma progression by modulating sonic hedgehog signaling in rats: A novel therapeutic approach

Liver cancer stands as the fourth leading global cause of death, and its prognosis remains grim due to the limited effectiveness of current medical interventions. Among the various pathways implicated in the development of hepatocellular carcinoma (HCC), the hedgehog signaling pathway has emerged as a crucial player. Itraconazole, a relatively safe and cost-effective antifungal medication, has gained attention for its potential as an anticancer agent. Its primary mode of action involves inhibiting the hedgehog pathway, yet its impact on HCC has not been elucidated. The main objective of this study was to investigate the effect of itraconazole on diethylnitrosamine-induced early-stage HCC in rats. Our findings revealed that itraconazole exhibited a multifaceted arsenal against HCC by downregulating the expression of key components of the hedgehog pathway, shh, smoothened (SMO), and GLI family zinc finger 1 (GLI1), and GLI2. Additionally, itraconazole extended survival and improved liver tissue structure, attributed mainly to its inhibitory effects on hedgehog signaling. Besides, itraconazole demonstrated a regulatory effect on Notch1, and Wnt/β-catenin signaling molecules. Consequently, itraconazole displayed diverse anticancer properties, including anti-inflammatory, antiangiogenic, antiproliferative, and apoptotic effects, as well as the potential to induce autophagy. Moreover, itraconazole exhibited a promise to impede the transformation of epithelial cells into a more mesenchymal-like phenotype. Overall, this study emphasizes the significance of targeting the hedgehog pathway with itraconazole as a promising avenue for further exploration in clinical studies related to HCC treatment.

Strategic Approach to Heterogeneity Analysis of Cutaneous Adnexal Carcinomas Using Computational Pathology and Genomics

Cutaneous adnexal tumors are neoplasms that arise from skin appendages. Their morphologic diversity and phenotypic variability with rare progression to malignancy make them difficult to diagnose and classify, and there is currently no established treatment strategy. To overcome these difficulties, this study investigated the transcription factor SOX9 expression, morphology, and genetics of skin adnexal tumors for understanding their biology, especially their histogenesis. We showed that cutaneous adnexal tumors and their nontumor counterparts of skin and appendages exhibit expression patterns similar to that of SOX9. Its expression intensity and pattern, as well as histopathologic evaluation of tumors, were analyzed using digital images of 69 normal skin adnexal 9-type organs and 185 skin adnexal 29-type tumors as references. It was possible to distinguish basal cell carcinoma from squamous cell carcinoma, sebaceous carcinoma, and pilomatrixoma with significant differences, along with porocarcinoma from squamous cell carcinoma. Furthermore, unsupervised machine learning "computational pathology" was used to derive a multiregion whole-exome sequencing fusion method termed "genocomputed pathology." The genocomputed pathology of three representable adnexal carcinomas (porocarcinoma, hidradenocarcinoma, and spiradenocarcinoma) was evaluated for total nine cases. We showed that there was more heterogeneity than expected within the tumors as well as the coexistence of components lacking driver fusion genes. The presence or absence of potential driver genes, such as PIK3CA, YAP1, and PTEN, in each region was identified, highlighting a therapeutic strategy for cutaneous adnexal carcinoma encompassing heterogeneous tumors.

Segmental basaloid follicular hamartomas derive from a post-zygotic SMO p.L412F pathogenic variant and express hair follicle development-related proteins in a pattern that distinguish them from basal cell carcinomas

Basaloid follicular hamartomas (BFH) are benign small basaloid skin tumors that can present as solitary or multiple lesions. Congenital BFH lesions arranged in a segmental distribution have been described, suggesting they derive from a somatic post-zygotic mutational event. Previously, BFH were described in Happle-Tinschert syndrome, which results from a post-zygotic SMO variant and is characterized by segmental BFH with variable involvement of the teeth, skeleton, and central nervous system. Here, we describe two patients with isolated segmental BFH and no systemic involvement. Paired whole exome sequencing of BFH and normal tissue revealed a pathogenic SMO c.1234 C>T, p.L412F variant restricted to BFH tissue. We characterized the proliferation index and expression of Hedgehog and Wnt/beta-catenin pathway related proteins in segmental BFH compared to sporadic basal cell carcinomas (BCCs) and found that segmental BFH had a lower proliferation index. Although segmental BFH expressed a similar level of Gli-1 compared to BCCs, levels of LEF-1 and SOX-9 expression in BFH were weaker for both and patchier for LEF-1. Our results show that a somatic SMO activating variant causes segmental BFH. Since these patients are prone to developing BCCs, differences in SOX9, LEF1, and Ki-67 expression can help distinguish between these two basaloid lesions.

Prognostic value of SOX9 in cervical cancer: Bioinformatics and experimental approaches

Among gynecological cancers, cervical cancer is a common malignancy and remains the leading cause of cancer-related death for women. However, the exact molecular pathogenesis of cervical cancer is not known. Hence, understanding the molecular mechanisms underlying cervical cancer pathogenesis will aid in the development of effective treatment modalities. In this research, we attempted to discern candidate biomarkers for cervical cancer by using multiple bioinformatics approaches. First, we performed differential expression analysis based on cervical squamous cell carcinoma and endocervical adenocarcinoma data from The Cancer Genome Atlas database, then used differentially expressed genes for weighted gene co-expression network construction to find the most relevant gene module for cervical cancer. Next, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed on the module genes, followed by using protein–protein interaction network analysis and Cytoscape to find the key gene. Finally, we validated the key gene by using multiple online sites and experimental methods. Through weighted gene co-expression network analysis, we found the turquoise module was the highest correlated module with cervical cancer diagnosis. The biological process of the module genes focused on cell proliferation, cell adhesion, and protein binding processes, while the Kyoto Encyclopedia of Genes and Genomes pathway of the module significantly enriched pathways related to cancer and cell circle. Among the module genes, SOX9 was identified as the hub gene, and its expression was associated with cervical cancer prognosis. We found the expression of SOX9 correlates with cancer-associated fibroblast immune infiltration in immune cells by Timer2.0. Furthermore, cancer-associated fibroblast infiltration is linked to cervical cancer patients’ prognosis. Compared to those in normal adjacent, immunohistochemical and real-time quantitative polymerase chain reaction (qPCR) showed that the protein and mRNA expression of SOX9 in cervical cancer were higher. Therefore, the SOX9 gene acts as an oncogene in cervical cancer, interactive with immune infiltration of cancer-associated fibroblasts, thereby affecting the prognosis of patients with cervical cancer.

Single-cell analysis of human basal cell carcinoma reveals novel regulators of tumor growth and the tumor microenvironment

How basal cell carcinoma (BCC) interacts with its tumor microenvironment to promote growth is unclear. We use singe-cell RNA sequencing to define the human BCC ecosystem and discriminate between normal and malignant epithelial cells. We identify spatial biomarkers of tumors and their surrounding stroma that reinforce the heterogeneity of each tissue type. Combining pseudotime, RNA velocity-PAGA, cellular entropy, and regulon analysis in stromal cells reveals a cancer-specific rewiring of fibroblasts, where STAT1, TGF-β, and inflammatory signals induce a noncanonical WNT5A program that maintains the stromal inflammatory state. Cell-cell communication modeling suggests that tumors respond to the sudden burst of fibroblast-specific inflammatory signaling pathways by producing heat shock proteins, whose expression we validated in situ. Last, dose-dependent treatment with an HSP70 inhibitor suppresses in vitro vismodegib-resistant BCC cell growth, Hedgehog signaling, and in vivo tumor growth in a BCC mouse model, validating HSP70's essential role in tumor growth and reinforcing the critical nature of tumor microenvironment cross-talk in BCC progression.

Notch–Sox9 Axis Mediates Hepatocyte Dedifferentiation in KrasG12V-Induced Zebrafish Hepatocellular Carcinoma

Liver cancer is one of the most prevalent cancers in humans. Hepatocytes normally undergo dedifferentiation after the onset of hepatocellular carcinoma, which in turn facilitates the progression of cancer. Although the process of hepatocellular carcinoma dedifferentiation is of significant research and clinical value, the cellular and molecular mechanisms underlying it are still not fully characterized. We constructed a zebrafish liver cancer model based on overexpression of the oncogene krasG12V to investigate the hepatocyte dedifferentiation in hepatocellular carcinoma. We found that, after hepatocarcinogenesis, hepatocytes dedifferentiated and the Notch signaling pathway was upregulated in this progress. Furthermore, we found that inhibition of the Notch signaling pathway or deficiency of sox9b both prevented hepatocyte dedifferentiation following hepatocellular carcinoma induction, reducing cancer metastasis and improving survival. In conclusion, we found that hepatocytes undergo dedifferentiation after hepatocarcinogenesis, a process that requires Notch signaling and likewise the activation of Sox9.

Transcriptomics Reveals the Mevalonate and Cholesterol Pathways Blocking as Part of the Bacterial Cyclodipeptides Cytotoxic Effects in HeLa Cells of Human Cervix Adenocarcinoma

The incidence of human cervix adenocarcinoma (CC) caused by papillomavirus genome integration into the host chromosome is the third most common cancer among women. Bacterial cyclodipeptides (CDPs) exert cytotoxic effects in human cervical cancer HeLa cells, primarily by blocking the PI3K/Akt/mTOR pathway, but downstream responses comprising gene expression remain unstudied. Seeking to understand the cytotoxic and anti-proliferative effects of CDPs in HeLa cells, a global RNA-Seq analysis was performed. This strategy permitted the identification of 151 differentially expressed genes (DEGs), which were either up- or down-regulated in response to CDPs exposure. Database analysis, including Gene Ontology (COG), and the Kyoto Encyclopedia of Genes and Genomes (KEGG), revealed differential gene expression on cancer transduction signals, and metabolic pathways, for which, expression profiles were modified by the CDPs exposure. Bioinformatics confirmed the impact of CDPs in the differential expression of genes from signal transduction pathways such as PI3K-Akt, mTOR, FoxO, Wnt, MAPK, P53, TGF-β, Notch, apoptosis, EMT, and CSC. Additionally, the CDPs exposure modified the expression of cancer-related transcription factors involved in the regulation of processes such as epigenetics, DNA splicing, and damage response. Interestingly, transcriptomic analysis revealed the participation of genes of the mevalonate and cholesterol biosynthesis pathways; in agreement with this observation, total cholesterol diminished, confirming the blockage of the cholesterol synthesis by the exposure of HeLa cells to CDPs. Interestingly, the expression of some genes of the mevalonate and cholesterol synthesis such as HMGS1, HMGCR, IDI1, SQLE, MSMO1, SREBF1, and SOAT1 was up-regulated by CDPs exposure. Accordingly, metabolites of the mevalonate pathway were accumulated in cultures treated with CDPs. This finding further suggests that the metabolism of cholesterol is crucial for the occurrence of CC, and the blockade of the sterol synthesis as an anti-proliferative mechanism of the bacterial CDPs, represents a reasonable chemotherapeutic drug target to explore. Our transcriptomic study supports the anti-neoplastic effects of bacterial CDPs in HeLa cells shown previously, providing new insights into the transduction signals, transcription factors and metabolic pathways, such as mevalonate and cholesterol that are impacted by the CDPs and highlights its potential as anti-neoplastic drugs.

Sox9-Increased miR-322-5p Facilitates BMP2-Induced Chondrogenic Differentiation by Targeting Smad7 in Mesenchymal Stem Cells

Bone morphogenetic protein 2 (BMP2) induces effective chondrogenesis of mesenchymal stem cells (MSCs) by promoting Sox9 expression. However, BMP2 also induces chondrocyte hypertrophy and endochondral ossification by upregulating Smad7 expression, which leads to the disruption of chondrogenesis. In addition, Smad7 can be inhibited by Sox9. Therefore, the underlying mechanism is not clear. Currently, an increasing number of studies have shown that microRNAs play a pivotal role in chondrogenic and pathophysiological processes of cartilage. The purpose of this study was to determine which microRNA is increased by Sox9 and targets Smad7, thus assisting BMP2 in maintaining stable chondrogenesis. We found that miR-322-5p meets the requirement through next-generation sequencing (NGS) and bioinformatic analysis. The targeting relationship between miR-322-5p and Smad7 was confirmed by dual-luciferase reporter assays, qPCR, and western blotting (WB). The in vitro study indicated that overexpression of miR-322-5p significantly inhibited Smad7 expression, thus causing increased chondrogenic differentiation and decreased hypertrophic differentiation, while silencing of miR-322-5p led to the opposite results. Flow cytometry (FCM) analysis indicated that overexpression of miR-322-5p significantly decreased the rate of early apoptosis in BMP2-stimulated MSCs, while silencing of miR-322-5p increased the rate. A mouse limb explant assay revealed that the expression of miR-322-5p was negatively correlated with the length of the BMP2-stimulated hypertrophic zone of the growth plate. An in vivo study also confirmed that miR-322-5p assisted BMP2 in chondrogenic differentiation. Taken together, our results suggested that Sox9-increased miR-322-5p expression can promote BMP2-induced chondrogenesis by targeting Smad7, which can be exploited for effective tissue engineering of cartilage.

SRY-Box Transcription Factor 9 (SOX9) Affects the Proliferation, Invasion and Epithelial to Mesenchymal Transition (EMT) of Intrahepatic Cholangiocarcinoma by Regulating Transforming Growth Factor β (TGFβ)/Smad Signaling

Intrahepatic cholangiocarcinoma (ICC) develops rapidly with a high malignancy. SOX9 expression is increased in several tumors. However, its expression and role in intrahepatic cholangiocarcinoma have not yet been elucidated. Real time PCR and Western blot were done to assess SOX9 expression in tumor tissues and adjacent tissues of ICC. ICC cell line QBC939 cells were separated into control group, SOX9 overexpression group and SOX9 siRNA group followed by analysis of cell survival by MTT assay, cell migration by cell scratch assay, cell invasion by transwell chamber, E-cadherin and Vimentin level by western blot, TGFβ/Smad signaling protein level by real time PCR. SOX9 level in tumor tissues was significantly increased compared to adjacent tissues (P < 0.05) and it was associated with TNM stage, tissue type and metastasis, and survival time (P < 0.05). Transfection of pcDNA3.1-SOX9 upregulated SOX9, promoted cell proliferation, migration and invasion, downregulated E-cadherin, upregulated Vimentin, TGF-β1 and Smad4 (P < 0.05). SOX9 siRNA transfection into QBC939 cells could significantly reverse the above mentioned changes (P < 0.05). SOX9 level is increased in intrahepatic cholangiocarcinoma and targeting SOX9 can inhibit cell migration and invasion, and EMT via regulating TGFβ/Smad signaling.

PI3K Promotes Basal Cell Carcinoma Growth Through Kinase-Induced p21 Degradation

Basal cell carcinoma (BCC) is a locally invasive epithelial cancer that is primarily driven by the Hedgehog (HH) pathway. Advanced BCCs are a critical subset of BCCs that frequently acquire resistance to Smoothened (SMO) inhibitors and identifying pathways that bypass SMO could provide alternative treatments for patients with advanced or metastatic BCC. Here, we use a combination of RNA-sequencing analysis of advanced human BCC tumor-normal pairs and immunostaining of human and mouse BCC samples to identify a PI3K pathway expression signature in BCC. Pharmacological inhibition of PI3K activity in BCC cells significantly reduces cell proliferation and HH signaling. However, treatment of Ptch1^fl/fl; Gli1-Cre^ERT2 mouse BCCs with the PI3K inhibitor BKM120 results in a reduction of tumor cell growth with no significant effect on HH signaling. Downstream PI3K components aPKC and Akt1 showed a reduction in active protein, whereas their substrate, cyclin-dependent kinase inhibitor p21, showed a concomitant increase in protein stability. Our results suggest that PI3K promotes BCC tumor growth by kinase-induced p21 degradation without altering HH signaling.

MTOR promotes basal cell carcinoma growth through atypical PKC

Advanced basal cell carcinomas (BCCs) are driven by the Hedgehog (HH) pathway and often possess inherent resistance to SMO inhibitors. Identifying and targeting pathways that bypass SMO could provide alternative treatments for patients with advanced or metastatic BCC. Here, we use a combination of RNA-sequencing analysis of advanced human BCC tumor-normal pairs and immunostaining of human and mouse BCC samples to identify an MTOR expression signature in BCC. Pharmacological inhibition of MTOR activity in BCC cells significantly reduces cell proliferation without affecting HH signalling. Similarly, treatment of the Ptch1 ^fl/fl ; Gli1-Cre^ERT2 mouse BCC tumor model with everolimus reduces tumor growth. aPKC, a downstream target of MTOR, shows reduced activity, suggesting that MTOR promotes tumor growth by activating aPKC and demonstrating that suppressing MTOR could be a promising target for BCC patients.

Sex determining region Y-box 9 induced microtubule formation and epithelial⁃mesenchymal transition in human oral squamous cell carcinoma CAL27 cells

OBJECTIVES

This study aimed to explore the effect of sex determining region Y-box 9 (SOX9) on the microtubule formation and epithelial-mesenchymal transition (EMT) of human oral squamous cell carcinoma (OSCC) CAL27 and the underlying mechanism.

METHODS

SOX9-shRNA1 and SOX9-shRNA2 were designed and synthesized and then transfected into CAL27 cells. The expression of SOX9 was detected by quantitative real-time polymerase chain reaction. Microtubule formation assay was used to detect the change in the number of microtubule nodules after interfering with SOX9. Immunofluorescence was used to detect the Vimentin content. Western blot was used to detect the protein expression of EMT marker molecules and Wnt/β-catenin pathway-related proteins, such as E-cadherin, N-cadherin, Fibronectin, Wnt, β-catenin, T-cell factor-4 (TCF-4).

RESULTS

The expression level of SOX9 significantly decreased after transfection with SOX9-shRNA1 and SOX9-shRNA2 in CAL27 cells (F=578.000, P=0.000; F=96.850, P=0.000). Interference with SOX9 inhibited the EMT of OSCC. After interference with SOX9, the number of tubules and Vimentin positive cells decreased significantly (F=169.700, P=0.000). The expression level of E-cadherin significantly increased (F=181.400, P=0.000). The expression levels of N-cadherin, Fibronectin, Wnt, β-catenin, and TCF-4 proteins significantly decreased (N-cadherin: F=101.400, P=0.000; Fibronectin: F=122.300, P=0.000; Wnt: F=70.290, P=0.000; β-catenin: F=81.740, P=0.000; TCF-4: F=37.020, P=0.000).

CONCLUSIONS

Interference with SOX9 decreased Vimentin content and inhibited the microtubule formation and protein expression of EMT marker molecules, as well as the expression of proteins related to the Wnt/β-catenin pathway. Thus, SOX9 can induce microtubule formation and EMT in CAL27, which was related to the inhibition of the Wnt/β-catenin pathway activation.

SOX9: An emerging driving factor from cancer progression to drug resistance

Dysregulation of transcription factors is one of the common problems in the pathogenesis of human cancer. Among them, SOX9 is one of the critical transcription factors involved in various diseases, including cancer. The expression of SOX9 is regulated by microRNAs (miRNAs), methylation, phosphorylation, and acetylation. Interestingly, SOX9 acts as a proto-oncogene or tumor suppressor gene, relying upon kinds of cancer. Recent studies have reported the critical role of SOX9 in the regulation of the tumor microenvironment (TME). Additionally, activation of SOX9 signaling or SOX9 regulated signaling pathways play a crucial role in cancer development and progression. Accumulating evidence also suggests that SOX9 acquires stem cell features to induce epithelial-mesenchymal transition (EMT). Moreover, SOX9 has been broadly studied in the field of cancer stem cell (CSC) and EMT in the last decades. However, the link between SOX9 and cancer drug resistance has only recently been discovered. Furthermore, its differential expression could be a potential biomarker for tumor prognosis and progression. This review outlined the various biological implications of SOX9 in cancer progression and cancer drug resistance and elucidated its signaling network, which could be a potential target for designing novel anticancer drugs.

Histone demethylase JMJD2D activates HIF1 signaling pathway via multiple mechanisms to promote colorectal cancer glycolysis and progression

Hypoxia-inducible factor 1 (HIF1) signaling pathway plays a key role in cancer progression by enhancing glycolysis through activating the transcription of glycolytic genes. JMJD2D, a histone demethylase that specifically demethylates H3K9me2/3, can promote colorectal cancer (CRC) progression. However, it is unknown whether JMJD2D could promote CRC progression by enhancing glycolysis through activating HIF1 signaling pathway. In this study, we found that downregulation of JMJD2D inhibited the glycolysis in CRC cells through suppressing HIF1 signaling pathway to downregulate glycolytic gene expression. Restoring HIF1 signaling by enforced expression of HIF1α in JMJD2D-knockdown CRC cells partially recovered CRC cell glycolysis, proliferation, migration, invasion, xenograft growth, and metastasis, suggesting that JMJD2D promotes CRC progression by enhancing glycolysis through activating HIF1 signaling pathway. JMJD2D activated HIF1 signaling pathway through three different mechanisms: JMJD2D cooperated with the transcription factor SOX9 to enhance mTOR expression and then to promote HIF1α translation; JMJD2D cooperated with the transcription factor c-Fos to enhance HIF1β transcription; JMJD2D interacted and cooperated with HIF1α to enhance the expression of glycolytic gene. The demethylase-defective mutant of JMJD2D could not induce the expression of mTOR, HIF1α, HIF1β, and glycolytic genes, suggesting that the demethylase activity of JMJD2D is important for glycolysis through activating HIF1 signaling. Clinically, a highly positive correlation between the expression of JMJD2D and mTOR, HIF1β, and several glycolytic genes in human CRC specimens was identified. Collectively, our study reveals an important role of JMJD2D in CRC progression by enhancing glycolysis through activating HIF1 signaling pathway.

Recent Advances in Signaling Pathways Comprehension as Carcinogenesis Triggers in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common malignant skin tumor. BCC displays a different behavior compared with other neoplasms, has a slow evolution, and metastasizes very rarely, but sometimes it causes an important local destruction. Chronic ultraviolet exposure along with genetic factors are the most important risk factors involved in BCC development. Mutations in the PTCH1 gene are associated with Gorlin syndrome, an autosomal dominant disorder characterized by the occurrence of multiple BCCs, but are also the most frequent mutations observed in sporadic BCCs. PTCH1 encodes for PTCH1 protein, the most important negative regulator of the Hedgehog (Hh) pathway. There are numerous studies confirming Hh pathway involvement in BCC pathogenesis. Although Hh pathway has been intensively investigated, it remains incompletely elucidated. Recent studies on BCC tumorigenesis have shown that in addition to Hh pathway, there are other signaling pathways involved in BCC development. In this review, we present recent advances in BCC carcinogenesis.

miR-18a expression in basal cell carcinoma and regulatory mechanism on autophagy through mTOR pathway

BACKGROUND

Basal cell carcinoma (BCC) is the most common form of skin carcinoma.

AIM

To investigate the function of key micro(mi)RNAs and to explore the potential molecular mechanisms involved in BCC.

METHODS

The microarray dataset GSE34535, which comprises seven BCC samples and seven control samples, was downloaded from the Gene Expression Omnibus database. Differentially expressed miRNAs (DE-miRNAs) were identified. We collected tissue samples from 20 patients with BCC and 20 healthy controls (HCs), to compare the miR-18a expression in their tissue samples. Expression of miR-18a in A431 and HaCaT cells was also assayed. Following this, we upregulated and downregulated miR-18a expression in A431 cells to examine the effects on cell proliferation, migration and apoptosis. To further investigate the relative mechanism, the proteins LC3, Beclin 1, Akt and mammalian target of rapamycin (mTOR) were examined by quantitative real-time PCR and Western blotting. For further verification, we examined the expression of LC3 in the 20 BCC and 20 HC tissue samples.

RESULTS

In total, 19 DE-miRNAs (13 upregulated and 6 downregulated) that were common to the BCC and HC groups were identified. Levels of miR-18a were about three-fold higher in BCC tissues and A431 cells compared with their respective control groups. In vitro, downregulation of miR-18a was shown to inhibit cell proliferation and activate autophagy via the Akt/mTOR signalling pathway, while upregulation of miR-18a promoted proliferation of these cells. LC3 was decreased in BCC compared with HC tissue samples.

CONCLUSIONS

Our data support an oncogenic role of miR-18a through a novel Akt/mTOR/Beclin 1/LC3 axis, and suggest that the antitumour effects of miR-18a inhibitor may make it suitable for BCC therapy.

Combined mTORC1/mTORC2 inhibition blocks growth and induces catastrophic macropinocytosis in cancer cells

The mammalian target of rapamycin (mTOR) pathway, which plays a critical role in regulating cellular growth and metabolism, is aberrantly regulated in the pathogenesis of a variety of neoplasms. Here we demonstrate that dual mTORC1/mTORC2 inhibitors OSI-027 and PP242 cause catastrophic macropinocytosis in rhabdomyosarcoma (RMS) cells and cancers of the skin, breast, lung, and cervix, whereas the effects are much less pronounced in immortalized human keratinocytes. Using RMS as a model, we characterize in detail the mechanism of macropinocytosis induction. Macropinosomes are distinct from endocytic vesicles and autophagosomes in that they are single-membrane bound vacuoles formed by projection, ruffling, and contraction of plasma membranes. They are positive for EEA-1 and LAMP-1 and contain watery fluid but not organelles. The vacuoles then merge and rupture, killing the cells. We confirmed the inhibition of mTORC1/mTORC2 as the underpinning mechanism for macropinocytosis. Exposure to rapamycin, an mTORC1 inhibitor, or mTORC2 knockdown alone had little or reduced effect relative to the combination. We further demonstrate that macropinocytosis depends on MKK4 activated by elevated reactive oxygen species. In a murine xenograft model, OSI-027 reduced RMS tumor growth. Molecular characterization of the residual tumors was consistent with the induction of macropinocytosis. Furthermore, relative to the control xenograft tumors, the residual tumors manifested reduced expression of cell proliferation markers and proteins that drive the epithelial mesenchymal transition. These data indicate a role of mTORC2 in regulating tumor growth by macropinocytosis and suggest that dual inhibitors could help block refractory or recurrent RMS and perhaps other neoplasms and other cancer as well.

Inhibition of the hedgehog pathway for the treatment of cancer using Itraconazole

Itraconazole (ITZ) is an anti-fungal drug that has been used in clinical practice for nearly 35 years. Recently, numerous experiments have shown that ITZ possesses anti-cancer properties. The Hedgehog (Hh) pathway plays a pivotal role in fundamental processes, including embryogenesis, structure, morphology and proliferation in various species. This pathway is typically silent in adult cells, and inappropriate activity is linked to various tumor types. The most important mechanism of ITZ in the treatment of cancer is inhibition of the Hh pathway through the inhibition of smoothened receptors (SMO), glioma-associated oncogene homologs (GLI), and their downstream targets. In this review, we discuss the mechanisms of ITZ in the treatment of cancer through inhibition of the Hh pathway, which includes anti-inflammation, prevention of tumor growth, induction of cell cycle arrest, induction of apoptosis and autophagy, prevention of angiogenesis, and drug resistance. We also discuss the clinical use of ITZ in many types of cancers. We hope this review will provide more information to support future studies on ITZ in the treatment of various cancers.

New developments in the treatment of basal cell carcinoma: update on current and emerging treatment options with a focus on vismodegib

Basal cell carcinoma (BCC) is the most common form of skin cancer worldwide. Although most BCCs can be treated by relatively simple surgical or nonsurgical methods, some patients with BCC may eventually develop advanced disease which can either be locally destructive or even include metastatic spread. The present review summarizes the current literature on the treatment of both early and advanced BCC with a focus on the hedgehog inhibitor vismodegib which has become an integral part of the management of patients with advanced BCC since its regulatory approval in 2012.