Progression Of Cutaneous Squamous Cell Carcinoma Research Articles

Retracted] MicroRNA‑451a prevents cutaneous squamous cell carcinoma progression via the 3‑phosphoinositide‑dependent protein kinase‑1‑mediated PI3K/AKT signaling pathway.

[This retracts the article DOI: 10.3892/etm.2020.9548.].

Abstract 6872: A spatio-temporal approach to mapping the dynamics of cutaneous squamous cell carcinoma progression and immunotherapy response: A journey through TiME

Abstract Background: Cutaneous squamous cell carcinoma (cSCC), arising from proliferation of malignant epidermal keratinocytes, is the second most common non-melanoma skin cancer. cSCC accounts for 75% of all skin cancer related deaths excluding melanoma, and metastatic and immunotherapy-resistant cases pose an emerging global threat. Tumor development is a gradual process characterized by high mutational burden and an immunosuppressive tumor immune microenvironment (TiME); therefore, identifying the underlying changes across the spatial and temporal landscape of these tumors will be crucial to understanding the key cellular and molecular drivers of disease progression and response. Methods: In this longitudinal study, we used a single-cell, whole-slide approach to mapping key proteins of immune lineage, tissue architecture, cellular metabolism, and stress to study the spatial landscape of cSCC at baseline (pre-treatment) and multiple time points over the course of immunotherapy with the aim to develop a temporal atlas of the tumor. An ultra-high plex antibody panel encompassing over 50 major determinants in the tumor microenvironment was employed on the PhenoCycler®-Fusion spatial biology platform. Deep bioinformatic analyses was performed to identify cellular phenotypes, spatial neighborhoods, heterogenous functional states and cellular interactions by spatial proximity determinations. Results: Previous studies in our laboratory have identified unique phenotypes correlating with response and resistance to immunotherapies in pre-treatment cSCC biopsies. Our results expand on these findings with temporal data tracking the dynamic changes in the TiME over the course of immune checkpoint inhibitor therapy. Apart from differences in immune cell composition and spatial localization patterns, we also saw differences in macrophage polarization and expression of metabolic markers in the responder and non-responder cohorts. Conclusions: Overall, ultrahigh-plex spatio-temporal monitoring of cSCC revealed distinct signatures of response and resistance and identified key features in the TiME that reveal deeper insights into the pathobiology of the tumor. Our discovery-based approach identifies novel biomarkers for patient stratification and therapeutic modulation. Citation Format: Niyati Jhaveri, Bassem Ben Cheikh, Dmytro Klymyshyn, Ning Ma, Aditya Pratapa, James Monkman, Nadine Nelson, Arutha Kulasinghe. A spatio-temporal approach to mapping the dynamics of cutaneous squamous cell carcinoma progression and immunotherapy response: A journey through TiME [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6872.

Radix Tetrastigma Hemsleyani Flavone represses cutaneous squamous cell carcinoma via Janus kinase/signal transducer and activator of transcription 3 pathway inactivation

Cutaneous squamous cell carcinoma (CSCC) is the second most common malignant skin tumor and significantly affects patients’ quality of life and health. The Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway activation is involved in CSCC development. Radix Tetrastigma hemsleyani flavone (RTHF) is an active Radix Tetrastigma extract (RTE), which was recently reported to have promising inhibitory effects on CSCC. However, the underlying functional mechanisms of this inhibition remain unknown. In the present study, A431 cells or SCL-1 cells were incubated with 1, 5, and 10 mg/mL RTHF for 48 h, respectively. A significantly increased wound closure rate, decreased number of migrated and invaded cells, decreased colony number, and elevated apoptotic rate were observed after treatment with 1, 5, and 10 mg/mL RTHF. Furthermore, after incubation with RTHF, p-JAK1/JAK1, p-JAK2/JAK2, and p-STAT3/STAT3 levels were drastically reduced. An A431 xenograft model was constructed, followed by oral administration of 15, 30, or 60 mg/kg RTHF for 21 consecutive days. A significantly lower increase in tumor volume and reduced tumor weight were observed in all RTHF-treated groups. In addition, JAK/STAT3 signaling was drastically repressed in tumor tissues. Collectively, RTHF inhibited CSCC progression, which may be associated with JAK/STAT3 pathway inactivation.

MicroRNA-124 plays an inhibitory role in cutaneous squamous cell carcinoma cells via targeting SNAI2, an immunotherapy determinant

PurposeMicroRNAs (miRs) play multiple roles during cutaneous squamous cell carcinoma (CSCC) progression. Previous studies suggest miR-124 could inhibit cancer development in CSCC. Methods: Obtained 63 pairs of CSCC and adjacent tissues for analysis. Cultured HaCaT and two CSCC cell lines (A431 and SCL-1) in DMEM (10 % FBS). Transfected cells using Lipofectamine 2000 with various miR-124 mimics, inhibitors, or Snail family transcriptional repressor 2 (SNAI2) expression plasmid. Performed a series of assays, including real-time quantitative PCR, Western blot, CCK8, wound healing, transwell, and luciferase reporter gene assay, to examine the effects of miR-124 on CSCC cells. Results: An evident downregulation of miR-124 in CSCC tissues, which was related to advanced disease stage and nodal metastasis. Overexpressing miR-124 could reduce the proliferation, migration, and invasion abilities of CSCC cells. It was verified that miR-124 targets the SNAI2 in CSCC cells. Moreover, ectopic expression of SNAI2 rescued the suppressive effects on CSCC cells induced by miR-124 overexpression. Furthermore, miR-124 increased cell sensitivity to cisplatin. Besides, SNAI2 is a critical factor in the immune-related aspects of CSCC and its modulation may influence the response to immunotherapy. Conclusion: We demonstrate that miR-124 inhibits CSCC progression through downregulating SNAI2, and thus it may be a molecular candidate for treating CSCC in the clinic.

Implication of Amyloid Precursor-like Protein 2 Expression in Cutaneous Squamous Cell Carcinoma Pathogenesis.

Regulatory functions of amyloid precursor-like protein 2 (APLP2) expression in intracellular trafficking of major histocompatibility complex class I (MHC-I) and biological behavior of tumor cells have been reported in various types of malignancies but not in cutaneous squamous cell carcinoma (CSCC). This study aimed to investigate the role of APLP2 expression in the pathogenesis of CSCC. The expression of APLP2 and a key modulator of cancer immune escape, MHC-I, were determined in CSCC tissue samples obtained from 141 patients using immunohistochemistry. The regulatory effects of APLP2 expression on the biological behavior and surface expression of MHC-I in CSCC cells were investigated by trypan blue assay, Matrigel invasion assay, and in vivo xenograft analysis. APLP2 immunoreactivity was high in 73 (51.8%) tissue samples from patients with CSCC and was significantly related to subcutaneous fat invasion and poor prognosis in our cohort. Moreover, proliferation of and invasion by CSCC cells were significantly reduced after APLP2 knockdown in CSCC cells both in vitro and in vivo. A significant association was found between APLP2 and membrane MHC-I expression in patients with CSCC. In vivo xenograft analysis showed that APLP2 knockdown increased membrane MHC-I expression in CSCC cells. APLP2 not only acts as an oncogene in CSCC progression but also as a possible modulator of cancer immune escape by influencing MHC-I expression on the cell surface. APLP2 may serve as a novel molecular biomarker and therapeutic target for patients with CSCC.

MicroRNA-21 Contributes to Cutaneous Squamous Cell Carcinoma Progression via Mediating TIMP3/PI3K/AKT Signaling Axis [Retraction

MicroRNA-21 Contributes to Cutaneous Squamous Cell Carcinoma Progression via Mediating TIMP3/PI3K/AKT Signaling Axis [Retraction

CircIFFO1 suppresses tumor growth and metastasis of cutaneous squamous cell carcinoma by targeting the miR-424-5p/NFIB axis.

Cutaneous squamous cell carcinoma (CSCC) is a severe malignancy derived from the skin. Circular RNAs (circRNAs) play an important role in the pathological process of many malignant tumors. Moreover, circIFFO1 is reported to be down-regulated in CSCC tissues compared with non-lesional skin tissues. This study aimed to explore the specific role and potential mechanism of circIFFO1 in CSCC progression. Cell proliferation ability was analyzed by 3-(4, 5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU) incorporation, and colony-formation assays. Cell cycle progression and apoptosis were detected by flow cytometry. Cell migration and invasion were examined by transwell assays. The interaction between microRNA-424-5p (miR-424-5p) and circIFFO1 or nuclear factor I/B (NFIB) was validated by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. Xenograft tumor assay and immunohistochemistry (IHC) assay were employed to analyze the tumorigenesis in vivo. CircIFFO1 level was down-regulated in CSCC tissues and cell lines. CircIFFO1 overexpression suppressed the proliferation, migration, invasion, and promoted apoptosis of CSCC cells. CircIFFO1 acted as a molecular sponge for miR-424-5p. The anti-tumor effects mediated by circIFFO1 overexpression in CSCC cells could be reversed by miR-424-5p overexpression. miR-424-5p interacted with the 3' untranslated region (3'UTR) of Nuclear Factor I/B (NFIB). miR-424-5p knockdown suppressed the malignant behaviors of CSCC cells, and NFIB knockdown counteracted the anti-tumor effects of miR-424-5p absence in CSCC cells. Additionally, circIFFO1 overexpression restrained xenograft tumor growth in vivo. CircIFFO1 suppressed the malignant behaviors of CSCC by mediating the miR-424-5p/NFIB axis, which provided new insights into the pathogenesis of CSCC.

310 HSP27 promotes cutaneous squamous cell carcinoma progression by inhibiting ferroptosis

310 HSP27 promotes cutaneous squamous cell carcinoma progression by inhibiting ferroptosis

Circ_0068631 sponges miR-139-5p to promote the growth and metastasis of cutaneous squamous cell carcinoma by upregulating HOXB7.

Circular RNAs (circRNAs) are often dysregulated in cancers and closely related to cancer progression, including cutaneous squamous cell carcinoma (CSCC). However, the role and mechanism of circ_0068631 in CSCC progression have not been reported. The expression of circ_0068631, microRNA-139-5p (miR-139-5p), and homeobox B7 (HOXB7) was measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, and colony formation assay were used to measure cell proliferation. Cell apoptosis was assessed by flow cytometry. Cell migration was detected by transwell assay. The interaction between miR-139-5p and circ_0068631 or HOXB7 was confirmed by dual-luciferase reporter assay. A xenograft tumor model was established to confirm the function of circ_0068631 in vivo. Circ_0068631 was upregulated in CSCC tissues and cells, and its silencing could inhibit CSCC cell proliferation and metastasis while promoting apoptosis in vitro, as well as restrain CSCC tumor growth in vivo. Circ_0068631 acted as a sponge of miR-139-5p, and miR-139-5p inhibition reversed the repressive effect of circ_0068631 knockdown on CSCC cell progression. Furthermore, HOXB7 was a target of miR-139-5p, and miR-139-5p inhibited the malignant behaviors by downregulating HOXB7 expression in CSCC cells. Further, circ_0068631 sponged miR-139-5p to regulate HOXB7 expression. Circ_0068631 functioned as a novel oncogene in CSCC progression by regulating miR-139-5p/HOXB7 axis, suggesting that circ_0068631 may be a potential target for CSCC treatment. Circ_0068631 was overexpressed in CSCC tissues and cells. Circ_0068631 downregulation suppressed CSCC progression via miR-139-5p. Circ_0068631 regulated HOXB7 via sponging miR-139-5p.

Proteasome Subunit Alpha Type-7 Expression Suppresses Cutaneous Squamous Cell Carcinoma Progression by Inhibiting Cancer-associated Cytokines.

Cutaneous squamous cell carcinoma (cSCC) is a common non-melanoma skin cancer, and its incidence is increasing. Proteasome subunit alpha type-7 (PSMA7) has been found to be aberrantly expressed in several cancers. However, whether it functions as a tumor suppressor or oncogene in the pathogenesis of cancers, particularly cSCC, remains controversial. Here, we aimed to investigate the functions of PSMA7 in cSCC pathogenesis. Clinicopathological characteristics were evaluated in 131 patients with cSCC using tissue sections. The expression of PSMA7, nucleotide-binding oligomerization domain-containing protein 1 (NOD1), and mitochondrial antiviral signaling protein (MAVS) was determined in cSCC tissue sections using immunohistochemical staining. The effect of PSMA7 expression on the biological behavior of cSCC cells was investigated in vitro. High immunoreactivity of PSMA7 (high-PSMA7) was detected in 53 (40.5%) patients with cSCC and was significantly associated with histologic grade (p=0.008) and favorable recurrence-free survival (p=0.018). The expression of PSMA7 and NOD1 (p=0.026) and MAVS (p=0.032) was negatively correlated in cSCC tissues. Contrary to the results of the cohort study, cell viability and invasiveness significantly decreased after PSMA7 down-regulation in cSCC cells in vitro. mRNA expression of tumor necrosis factor-alpha, interleukin-1 alpha (IL-1α), IL-6, and IL-8 were significantly increased after PSMA7 down-regulation in cSCC cells (all p=0.002). PSMA7-mediated degradation of NOD1 and MAVS as well as the subsequent reduction of the cancer-associated cytokine network may be a crucial mechanism of the antitumoral function of PSMA7 in patients with cSCC.

T-box transcription factor 2 mediates antitumor immune response in cutaneous squamous cell carcinoma by regulating the expression of programmed death ligand 1.

Cutaneous squamous cell carcinoma (CSCC) is the second largest nonmelanoma skin cancer in humans; effective treatment options for metastatic CSCC are still in short. In this study, we aimed to explore the function of T-box transcription factor 2 (TBX2) in CSCC. The expression level of TBX2 was determined in CSCC samples and cell lines. Programmed death ligand 1 (PD-L1) expression was also analyzed in human CSCC samples. Furthermore, SCC13 cells were transfected with TBX2-DN (loss of function) or normal TBX2 to check its role in regulating PD-L1. The expression level of TBX2 was positively correlated with the stage of CSCC. CSCC tumor cell lines have significantly higher expression levels of TBX2 than normal skin cell lines, and SCC13 cells showed the highest expression. PD-L1 expressions were upregulated during the progression of CSCC, and positively correlated with TBX2. Furthermore, PD-L1 expression increased in SCC13 cells overexpressing TBX2. However, TBX2 did not regulate the activation of IFNγ signal, but mediated the expression of interferon regulatory factor 1 (IRF1) and PD-L1 in both SCC13 and PDV cells. TBX2 could mediate antitumor immune response in CSCC by regulating the expression of PD-L1 through IRF1. It might be a prognostic marker in CSCC and synergistic target for PD-1 immunotherapy.

Alkannin exerts antitumor properties in cutaneous squamous cell carcinoma by inducing apoptosis and shifting the M1/M2 polarization of tumor-associated macrophages by upregulating PTEN.

Cutaneous squamous cell carcinoma (CSCC) is a common cancer in humans and is the second major type of skin cancer that causes death in humans. In this article, we investigated the effects of alkannin on CSCC progression. We revealed that alkannin curbed CSCC cell viability in a dose-dependent manner and accelerated CSCC cell apoptosis. In addition, alkannin expedited macrophage M1 polarization while curbing M2 polarization. Moreover, alkannin elevated phosphatase and tensin homolog (PTEN) abundance in CSCC cells. The results of bioinformatics analysis revealed that alkannin might modulate CSCC via PTEN. Downregulation of PTEN reversed the effects of alkannin on apoptosis of CSCC cells and M1/M2 polarization of macrophages. Alkannin reduced CSCC tumor growth in a mouse xenograft model. In conclusion, alkannin curbed the advancement of CSCC by expediting apoptosis and facilitating M1 polarization of macrophages by upregulating PTEN. These data may offer a therapeutic approach against CSCC.

Knockdown of circRNA circEBF1 inhibits cutaneous squamous cell carcinoma progression by regulating the miR-1247-5p/CSF3 axis.

Cutaneous squamous cell carcinoma (CSCC) is one of the causes of cancer-related death worldwide. Circular RNAs (circRNAs) play a vital role in the pathological process of many malignant tumors. This study aimed to explore the specific role and potential mechanism of circRNA EBF transcription factor 1 (circEBF1) in CSCC. The levels of circEBF1, microRNA-1247-5p (miR-1247-5p) and colony stimulating factor 3 (CSF3) were determined by quantitative real-time PCR and Western blot. Cell proliferation was assessed by colony formation assay. Cell migration, invasion and apoptosis were evaluated by Transwell, wound healing, flow cytometry and Western blot assays. Cellular glycolysis, including glucose consumption, lactate production, and ATP level, was detected by commercial kits. The binding relationship between miR-1247-5p and circEBF1 or CSF3 was verified by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay. Xenograft experiment was conducted to analyze tumor growth in vivo. circEBF1 and CSF3 were up-regulated, while miR-1247-5p was down-regulated in CSCC tissues and cells. Interference of circEBF1 hindered the proliferation, migration, invasion, and glycolysis of CSCC cells and promoted apoptosis. In addition, circEBF1 sponged miR-1247-5p to regulate CSCC cell development. Also, miR-1247-5p suppressed CSCC cell progression by inhibiting CSF3. Moreover, depletion of circEBF1 blocked CSCC tumor growth in vivo. Down-regulation of circEBF1 impeded CSCC progression by regulating the miR-1247-5p/CSF3 pathway, suggesting that circEBF1 might be a promising therapeutic target for CSCC.

Circular RNA circFADS2 inhibits the progression of cutaneous squamous cell carcinoma by regulating miR-766-3p/HOXA9 axis.

Mounting evidence indicates that circular RNAs (circRNAs) play vital roles in human diseases, especially in cancers. However, the biological functions and underlying mechanism of circRNA fatty acid desaturase 2 (circFADS2) in cutaneous squamous cell carcinoma (CSCC) have not been reported. The expression levels of circFADS2, microRNA-766-3p (miR-766-3p) and homeobox A9 (HOXA9) were determined by quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was used to determine cell cycle distribution. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) and colony formation assays. Wound healing and transwell assays were used to assess cell migration and invasion abilities. Glycolysis was examined via the measurement of extracellular acidification rate (ECAR). All protein levels were detected by western blot assay. The interaction between miR-766-3p and circFADS2 or HOXA9 was predicted by bioinformatics software and confirmed by dual-luciferase reporter, RNA pull-down, and RNA Immunoprecipitation (RIP) assays. The mouse xenograft model was established to investigate the role of circFADS2 in vivo. CircFADS2 was downregulated in CSCC tissues and cells. CircFADS2 overexpression inhibited CSCC cell proliferation, metastasis and glycolysis. Moreover, miR-766-3p was able to directly bind to circFADS2, and circFADS2 played an anti-cancer role in CSCC by downregulating miR-766-3p. In addition, HOXA9 was a direct target of miR-766-3p, and miR-766-3p inhibition suppressed CSCC cell proliferation, metastasis and glycolysis by upregulating HOXA9. Furthermore, circFADS2 acted as a sponge of miR-766-3p to regulate HOXA9 expression. Besides, circFADS2 suppressed tumor growth in vivo. CircFADS2 suppressed CSCC progression by regulating miR-766-3p/HOXA9 axis, which might provide a promising therapeutic target for CSCC.

Artesunate restrains the malignant progression of human cutaneous squamous cell carcinoma cells via the suppression of the PI3K/AKT pathway

PurposeArtesunate (ART) is recognized for its anticancer activity, but a few studies concentrate on its anti-skin cancer effect. This study emphazied this aspect and preliminarily discussed the impact and mechanism of ART on cutaneous squamous cell carcinoma (CSCC). MethodsThe viability of HaCaT and CSCC cells treated with ART (0, 30, 60, 90, 120, 150, 180, or 210 μmol/L) for 48 h were assessed utilizing cell counting kit-8. Next, the migration, invasion, proliferation, apoptosis, and cell cycle of CSCC cells treated with ART were evaluated by dint of cell function experiments. Then, cell cycle-, apoptosis-, and phosphatidylinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway-related markers were examined via western blot or quantitative real-time PCR. Moreover, the influences of ART and PI3K/AKT agonist IGF-I on CSCC cell biological behaviors were gauged again. ResultsThe suppressive role of ART (30, 60, 90, 120, 150, 180, or 210 μmol/L) was stronger in viability of CSCC cells than in viability of HaCaT cells. ART evidently attenuated the migration, invasion and proliferation, lessened cell numbers at G2/M phase and triggered apoptosis of CSCC cells. At the molecular level, ART regulated cell cycle-, apoptosis-, and PI3K/AKT pathway-related markers in CSCC cells. Moreover, the suppression of ART on CSCC cell malignant phenotypes was reversed by PI3K/AKT agonist IGF-I. ConclusionART restrains the malignant progression of CSCC, which may be intensely related to the PI3K/AKT pathway repression.

Significant Biomarkers Identification Associated with Cutaneous Squamous Cell Carcinoma Progression.

BackgroundThis study aimed to identify significant genes associated with cutaneous squamous cell carcinoma (CSCC) initiation and development.MethodsThe overlapped differential expressed genes (DEGs) between normal and CSCC samples were firstly screened out, followed by KEGG analysis. The top 10 hub genes were then detected from the whole protein–protein interaction (PPI) network. Further, important biomarkers continuously associated with actinic keratosis (AK), CSCC, and CSCC invasion was successively filtrated. GSEA analysis was finally performed to reveal potential mechanisms associated with biomarkers.ResultsA total of 179 DEGs were identified, which were enriched in pathways in cancer, PI3K-Akt signaling pathway, and human papillomavirus infection. The 10 hub genes were firstly identified from the PPI network, and they were all highly expressed in AK tissues compared with normal tissues. Next, we found that 6 genes were overexpressed in CSCC compared with AK tissues. Further, we identified that the expression of 2 genes (MYBL2 and TK1) was higher in CSCC invasion groups compared with samples without invasion. Through a series of filtrations, we confirmed that MYBL2 and TK1 were the most significant biomarkers associated with CSCC initiation and progression. The pan-cancer analysis further supported their prognostic value in human cancers. GSEA analysis found that they positively correlated with N glycan biosynthesis and p53 signaling pathways.ConclusionMYBL2 and TK1 were proved to play a vital role in CSCC tumorigenesis and progression, which may act as promising biomarkers or therapeutic targets for accurate diagnosis and treatment of CSCC.

Circular RNA circ-LARP1B contributes to cutaneous squamous cell carcinoma progression by targeting microRNA-515-5p/TPX2 microtubule nucleation factor axis

ABSTRACT Circular RNAs (circRNAs) have shown pivotal regulatory roles in tumorigenesis and progression. Our purpose was to analyze the role of circRNA La ribonucleoprotein 1B (circ-LARP1B; hsa_circ_0070934) in cutaneous squamous cell carcinoma (CSCC) progression and its associated mechanism. Cell viability, colony formation ability, migration, and invasion were analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide (MTT) assay, colony formation assay, wound healing assay, and transwell invasion assay. Flow cytometry was performed to analyze cell apoptosis and cell cycle progression. Cell glycolytic metabolism was analyzed using Glucose Uptake Colorimetric Assay kit, Lactate Assay Kit II, and ATP colorimetric Assay kit. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to verify the interaction between microRNA-515-5p (miR-515-5p) and circ-LARP1B or TPX2 microtubule nucleation factor (TPX2). Circ-LARP1B expression was up-regulated in CSCC tissues and cell lines. Circ-LARP1B knockdown suppressed cell viability, colony formation ability, migration, invasion, cell cycle progression, and glycolysis and triggered cell apoptosis in CSCC cells. miR-515-5p was a direct target of circ-LARP1B in CSCC cells, and circ-LARP1B silencing-mediated anti-tumor effects were largely counteracted by miR-515-5p knockdown. miR-515-5p directly interacted with the 3ʹ untranslated region (3ʹUTR) of TPX2. TPX2 overexpression largely overturned miR-515-5p-mediated anti-tumor effects in CSCC cells. Circ-LARP1B could up-regulate TPX2 expression by sponging miR-515-5p in CSCC cells. Circ-LARP1B knockdown suppressed tumor growth in vivo. In conclusion, circ-LARP1B contributed to CSCC progression by targeting miR-515-5p/TPX2 axis. The circ-LARP1B/miR-515-5p/TPX2 axis might provide novel therapeutic targets for CSCC patients.

HOTAIR/Sp1/miR-199a critically regulates cancer stemness and malignant progression of cutaneous squamous cell carcinoma.

The long non-coding RNA (lncRNA), HOX antisense intergenic RNA (HOTAIR) is a well-characterized oncogene in multiple human cancers, but not in cutaneous squamous cell carcinoma (CSCC). In this study, we focused on investigating the potential role of HOTAIR in stemness of CSCC. By measuring its expression using RT-qPCR in CSCC vs. normal tissues, as well as in CSCC cell lines A431 or SCC13, A431- or SCC13-derived CSCC stem cells (CSCSCs), and normal skin fibroblasts (HSFs), we detected higher expression of HOTAIR in CSCC than in normal tissues, in recurrent than in non-recurrent CSCC tissues, in CSCCs and CSCSCs than in HSFs, and particularly, in CSCSCs than in CSCCs. Kaplan-Meier analysis suggested that higher expression of HOTAIR was positively correlated with worse overall survival of CSCC patients. Functional assays on colony formation, EdU incorporation, sphere formation, western blot on stem-cell biomarkers, and in vivo models showed that HOTAIR was essential in maintaining multiple stem cell phenotypes of CSCSCs in vitro and in vivo xenograft growth as well as metastasis. Mechanistically, HOTAIR directly interacted with and up-regulated Sp1. Sp1 then induced DNMT1-mediated promoter methylation and direct transcriptional repression of miR-199a-5p. Targeting Sp1 or DNMT1 further boosted the in vivo anti-tumor and anti-metastasis activities of targeting HOTAIR. In conclusion, HOTAIR, by up-regulating Sp1 and targeting miR-199a, promotes stemness and progression of CSCC. Targeting HOTAIR, Sp1 or the underlying mechanisms may thus benefit CSCC treatment.

A study of the effects of delayed patient presentation on cutaneous SCC progression

A cohort study of patients, who underwent cutaneous squamous cell carcinoma (SCC) excision, was undertaken to evaluate the effects of the COVID-19 pandemic on treatment times and histopathological features. We identified all patients who had SCCs excised in October 2020 (pandemic group); the control group included all patients who underwent excision of SCCs during October 2019 (pre-pandemic group). Collected data included SCC subtype, thickness, size, clearance margins, referral details, patient comorbidities and operative data. There were 140 patients (174 SCCs; pre-pandemic group=74; pandemic group=100) identified for study inclusion. Both groups were well matched for age, sex, previous history of cancer, cutaneous SCC and histological subtype. There was a delay in median patient presentation time to the GP in the pandemic versus pre-pandemic group (106 days vs. 56 days, p <0.001); this led to a longer overall time to surgery (167 days vs. 110.5 days, p<0.001). Pandemic group SCCs had larger median Breslow depths (4mm vs. 3mm, p=0.01), a greater proportion of Clark's level 4 and 5 lesions (76.9% vs. 61.1%, p=0.03), and a higher rate of high (20-40mm) and very high (>40mm) risk SCCs as defined by British Association of Dermatology diameter criteria (56.1% vs. 39.2%, p=0.03), versus the pre-pandemic group. There was a 57-day median SCC treatment delay, and an associated development of higher risk SCCs by the time of surgery. Despite the challenges of a pandemic, patients should seek early consultation for suspicious skin changes, and healthcare systems should maintain skin cancer treatment pathways.

Transposon mutagenesis identifies cooperating genetic drivers during keratinocyte transformation and cutaneous squamous cell carcinoma progression.

The systematic identification of genetic events driving cellular transformation and tumor progression in the absence of a highly recurrent oncogenic driver mutation is a challenge in cutaneous oncology. In cutaneous squamous cell carcinoma (cuSCC), the high UV-induced mutational burden poses a hurdle to achieve a complete molecular landscape of this disease. Here, we utilized the Sleeping Beauty transposon mutagenesis system to statistically define drivers of keratinocyte transformation and cuSCC progression in vivo in the absence of UV-IR, and identified both known tumor suppressor genes and novel oncogenic drivers of cuSCC. Functional analysis confirms an oncogenic role for the ZMIZ genes, and tumor suppressive roles for KMT2C, CREBBP and NCOA2, in the initiation or progression of human cuSCC. Taken together, our in vivo screen demonstrates an extremely heterogeneous genetic landscape of cuSCC initiation and progression, which can be harnessed to better understand skin oncogenic etiology and prioritize therapeutic candidates.