Comprehensive pan-cancer analysis reveals SIRT5 is a predictive biomarker for prognosis and immunotherapy response.

BACKGROUND: Sirtuin 5 (SIRT5) is a promising therapeutic target involved in regulating multiple metabolic pathways in cells and organisms. The role of SIRT5 in cancer is currently unclear, and a comprehensive systematic pan-cancer analysis is required to explore its value in diagnosis, prognosis, and immune function. METHODS: We investigated the role of SIRT5 in tumorigenesis, diagnosis, prognosis, metabolic pathways, the immune microenvironment, and pan-cancer therapeutic response. Moreover, we explored chemicals affecting the expression of SIRT5 and computed the relationship between SIRT5 and drug sensitivity. Finally, the role of SIRT5 in melanoma was analyzed using a series of experiments in vitro and in vivo. RESULTS: We found that SIRT5 is differentially expressed and shows early diagnostic value in various tumors and that somatic cell copy number alterations and DNA methylation contribute to its aberrant expression. SIRT5 expression correlates with clinical features. Besides, it is negatively (positively) correlated with several metabolic pathways and positively (negatively) correlated with several important metastasis-related and immune-related pathways. High SIRT5 expression predicts poor (or good) prognosis in various tumors and can affect drug sensitivity. We also demonstrated that SIRT5 expression significantly correlates with immunomodulator-associated molecules, lymphocyte subpopulation infiltration, and immunotherapeutic response biomarkers. In addition, we showed that SIRT5 is differentially expressed in immunotherapy cohorts. In addition, we explored various chemicals that may affect SIRT5 expression. In conclusion, we demonstrated that SIRT5 is a key pathogenic gene that promotes melanoma progression. CONCLUSION: Our study provides a systematic analysis of SIRT5 and its regulatory genes. SIRT5 has excellent diagnostic and prognostic capabilities for many cancers. This may remodel the tumor microenvironment. The potential of SIRT5-based cancer therapies is emphasized and helps predict the response to immunotherapy.

Morusin shows potent antitumor activity for melanoma through apoptosis induction and proliferation inhibition.

BACKGROUND: The discovery of new anti-melanoma drugs with low side effect is urgently required in the clinic. Recent studies showed that morusin, a flavonoid compound isolated from the root bark of Morus Alba, has the potential to treat multiple types of cancers, including breast cancer, gastric cancer, and prostate cancer. However, the anti-cancer effect of morusin on melanoma cells has not been investigated. METHODS: We analyzed the effects of morusin on the proliferation, cell cycle, apoptosis, cell migration and invasion ability of melanoma cells A375 and MV3, and further explored the effects of morusin on tumor formation of melanoma cell. Finally, the effects of morusin on the proliferation, cycle, apoptosis, migration and invasion of A375 cells after knockdown of p53 were detected. RESULTS: Morusin effectively inhibits the proliferation of melanoma cells and induces cell cycle arrest in the G2/M phase. Consistently, CyclinB1 and CDK1 that involved in the G2/M phase transition were down-regulated upon morusin treatment, which may be caused by the up-regulation of p53 and p21. In addition, morusin induces cell apoptosis and inhibits migration of melanoma cells, which correlated with the changes in the expression of the associated molecules including PARP, Caspase3, E-Cadherin and Vimentin. Moreover, morusin inhibits tumor growth in vivo with little side effect on the tumor-burden mice. Finally, p53 knockdown partially reversed morusin-mediated cell proliferation inhibition, cell cycle arrest, apoptosis, and metastasis. CONCLUSION: Collectively, our study expanded the spectrum of the anti-cancer activity of morusin and guaranteed the clinical use of the drug for melanoma treatment.

Morusinol extracted from Morus alba induces cell cycle arrest and apoptosis via inhibition of DNA damage response in melanoma by CHK1 degradation through the ubiquitin-proteasome pathway.

BACKGROUD: Flavonoids have a variety of biological activities, such as anti-inflammation, anti-tumor, anti-thrombosis and so on. Morusinol, as a novel isoprene flavonoid extracted from Morus alba root barks, has the effects of anti-arterial thrombosis and anti-inflammatory in previous studies. However, the anti-cancer mechanism of morusinol remains unclear. PURPOSE: In present study, we mainly studied the anti-tumor effect of morusinol and its mode of action in melanoma. METHODS: The anti-cancer effect of morusinol on melanoma were evaluated by using the MTT, EdU, plate clone formation and soft agar assay. Flow cytometry was used for detecting cell cycle and apoptosis. The É£-H2AX immunofluorescence and the alkaline comet assay were used to detect DNA damage and the Western blotting analysis was used to investigate the expressions of DNA-damage related proteins. Ubiquitination and turnover of CHK1 were also detected by using the immunoprecipitation assay. The cell line-derived xenograft (CDX) mouse models were used in vivo to evaluate the effect of morusinol on tumorigenicity. RESULTS: We demonstrated that morusinol not only had the ability to inhibit cell proliferation, but also induced cell cycle arrest at G0/G1 phase, caspase-dependent apoptosis and DNA damage in human melanoma cells. In addition, morusinol effectively inhibited the growth of melanoma xenografts in vivo. More strikingly, CHK1, which played an important role in maintaining the integrity of cell cycle, genomic stability and cell viability, was down-regulated in a dose- and time-dependent manner after morusinol treatment. Further research showed that CHK1 was degraded by the ubiquitin-proteasome pathway. Whereafter, morusinol-induced cell cycle arrest, apoptosis and DNA damage were partially salvaged by overexpressing CHK1 in melanoma cell lines. Herein, further experiments demonstrated that morusinol increased the sensitivity of dacarbazine (DTIC) to chemotherapy for melanoma in vitro and in vivo. CONCLUSION: Morusinol induces CHK1 degradation through the ubiquitin-proteasome pathway, thereby inducing cell cycle arrest, apoptosis and DNA damage response in melanoma. Our study firstly provided a theoretical basis for morusinol to be a candidate drug for clinical treatment of cancer, such as melanoma, alone or combinated with dacarbazine.

Corrigendum: Dihydrocapsaicin inhibits cell proliferation and metastasis in melanoma via down-regulating ß-catenin pathway.

[This corrects the article DOI: 10.3389/fonc.2021.648052.].

Erratum: Lycorine hydrochloride inhibits melanoma cell proliferation, migration and invasion via down-regulating p21Cip1/WAF1.

[This corrects the article on p. 1391 in vol. 11, PMID: 33948364.].

Lycorine hydrochloride inhibits melanoma cell proliferation, migration and invasion via down-regulating p21Cip1/WAF1.

Lycorine hydrochloride (LH) is an active ingredient sourced from the medicinal herb Lycoris radiata. Previous studies have suggested that LH exerts tumor suppression activity in several human cancers. However, the anti-cancer effect of LH in melanoma and the potential molecular mechanisms still need to be further studied. p21Cip1/WAF1, unlike its traditional cyclin-dependent kinase (CDK) inhibitor role, is believed to act as an oncogene under certain cellular conditions. In this research, an increased expression of p21Cip1/WAF1 was found in human melanoma tissues and positively related to the tumor invasion depth. High level of p21Cip1/WAF1 was found to correlate with bad outcomes of melanoma patients by Kaplan-Meier survival analysis. Functional experiments demonstrated that the proliferation, migration and invasion ability of A375 and MV3 melanoma cells was powerfully inhibited by LH through inducing S phase cell cycle arrest and regulating epithelial-mesenchymal transition (EMT). In NOD/SCID mice model, LH effectively inhibited the xenograft tumor growth and lung metastasis of A375 cells. Further research revealed that LH reduced p21Cip1/WAF1 protein by accelerating its ubiquitination. Importantly, the LH-induced suppression of cell proliferation and metastasis was rescued by p21Cip1/WAF1 overexpression, both in vitro an in vivo. Taken together, LH, which suppresses the proliferation and metastasis of melanoma cells via down-regulating p21Cip1/WAF1, is expected to be developed as an effective medicine for melanoma therapy.

Dihydrocapsaicin Inhibits Cell Proliferation and Metastasis in Melanoma via Down-regulating ß-Catenin Pathway.

Dihydrocapsaicin (DHC) is one of the main components of capsaicinoids in Capsicum. It has been reported that DHC exerts anti-cancer effects on diverse malignant tumors, such as colorectal cancer, breast cancer, and glioma. However, studies focused on the effect of DHC upon melanoma have rarely been done. In the present study, melanoma A375 and MV3 cell lines were treated with DHC and the cell proliferation, migration, and invasion were significantly suppressed. Furthermore, DHC effectively inhibited xenograft tumor growth and pulmonary metastasis of melanoma cells in NOD/SCID mice model. It was identified that ß-catenin, which plays significant roles in cell proliferation and epithelial-mesenchymal transition, was down-regulated after DHC treatment. In addition, cyclin D1, c-Myc, MMP2, and MMP7, which are critical in diverse cellular process regulation as downstream proteins of ß-catenin, were all decreased. Mechanistically, DHC accelerates ubiquitination of ß-catenin and up-regulates the beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) in melanoma cells. The DHC induced suppression of cell proliferation, migration, and invasion were partly rescued by exogenous ß-catenin overexpression, both in vitro and in vivo. Taken together, DHC may serve as a candidate natural compound for human melanoma treatment through ß-catenin pathway.

CSN6 promotes melanoma proliferation and metastasis by controlling the UBR5-mediated ubiquitination and degradation of CDK9.

As a critical subunit of the constitutive photomorphogenesis 9 (COP9) signalosome (CSN), CSN6 is upregulated in some human cancers and plays critical roles in tumorigenesis and progression, but its biological functions and molecular mechanisms in melanoma remain unknown. Our study showed that CSN6 expression was upregulated in melanoma patients and cells, and correlated with poor survival in melanoma patients. In melanoma cells, CSN6 knockdown remarkably inhibited cell proliferation, tumorigenicity, migration, and invasion, whereas CSN6 recovery rescued the proliferative and metastatic abilities. Notably, we identified that CSN6 stabilized CDK9 expression by reducing CDK9 ubiquitination levels, thereby activating CDK9-mediated signaling pathways. In addition, our study described a novel CSN6-interacting E3 ligase UBR5, which was negatively regulated by CSN6 and could regulate the ubiquitination and degradation of CDK9 in melanoma cells. Furthermore, in CSN6-knockdown melanoma cells, UBR5 knockdown abrogated the effects caused by CSN6 silencing, suggesting that CSN6 activates the UBR5/CDK9 pathway to promote melanoma cell proliferation and metastasis. Thus, this study illustrates the mechanism by which the CSN6-UBR5-CDK9 axis promotes melanoma development, and demonstrate that CSN6 may be a potential biomarker and anticancer target in melanoma.

ZC3H15 Correlates with a Poor Prognosis and Tumor Progression in Melanoma.

Zinc figure CCCH-type containing 15 (ZC3H15), also called developmentally regulated GTP-binding protein 1 (DRG1) family regulatory protein 1 (DFRP1), is a zinc finger containing protein. Despite playing a role in cellular signaling, it is found overexpressed in acute myeloid leukemia and also an independent prognostic marker in hepatocellular carcinoma patients. However, the biological effect of ZC3H15 in malignant melanoma (MM) remains unexplored. The expression of ZC3H15 in patients was analyzed using the R2: Genomics Analysis and Visualization Platform database. Immunohistochemical analysis, western blot, and qRT-PCR were used to detect ZC3H15 expression in melanoma tissues and cell lines. MTT, BrdU, flow cytometry assay, transwell, and western blot were performed to explore the proliferation, cell cycle, invasion, and migration of melanoma cells. We undertaken colony formation assay in vitro and tumor xenograft in vivo to detect the tumorigenicity of melanoma cells. In the present study, ZC3H15 was demonstrated highly expressed in melanoma tissues and cells. Elevated ZC3H15 impairs the survival of melanoma patients. Meanwhile, attenuation of ZC3H15 in melanoma cells inhibited cell proliferation and induced cycle arrest at G0/G1 phase. Consistently, the expression of cell cycle-related proteins cyclin dependent kinase 4 (CDK4), CDK6, and cyclin D1 (CCND1) was decreased while p21 was upregulated. Furthermore, we found the migration and invasion abilities were inhibited in ZC3H15-knockdown melanoma cells. In addition, downregulation of ZC3H15 resulted in inhibition of colony formation abilities in vitro and tumorigenesis in vivo. ZC3H15 promotes proliferation, migration/invasion, and tumorigenicity of melanoma cells. As a promising biomarker and therapeutic target in MM, ZC3H15 is worthy of further exploration.

Dehydrocorydaline inhibits cell proliferation, migration and invasion via suppressing MEK1/2-ERK1/2 cascade in melanoma.

Purpose: Alkaloids are naturally occurring chemical compounds that are widely distributed in plants, and have pharmaceutical values and low toxicity. In recent years, some of them have been demonstrated to be promising therapeutic drug candidates for cancer treatment. Herein, we tried to explore the antitumor effect of dehydrocorydaline (DHC), a natural alkaloid isolated from Corydalis, on malignant melanoma. Methods: We treated two malignant metastatic melanoma cell lines, A375 and MV3, and a normal melanocyte cell line, PIG1, with various concentrations of DHC for set amounts of time, and detected cell proliferation, migration, and invasion by using MTT, BrdU, transwell, Western blot and soft agar assay in vitro and tumorigenicity in the xenografts in vivo. Results: Our results showed that DHC dramatically blocked cell proliferation and led to cell cycle arrest at G0/G1 phase and downregulated the expressions of cell cycle regulators CDK6 and Cyclin D1 in melanoma cells. However, DHC had little inhibitory effect on normal melanocyte cell line PIG-1. Meanwhile, DHC suppressed cell invasion and migration through modulating the epithelial-mesenchymal transition (EMT) markers including E-cadherin, vimentin, as well as ß-catenin. In addition, DHC also significantly attenuated tumor growth in vivo. The expressions of cell cycle-related and metastasis-related proteins were further confirmed by immunohistochemical staining in the xenografts. Importantly, MEK1/2-ERK1/2 cascade was inactivated after DHC treatment and ERK activator t-butylhydroquinone (tBHQ) treatment rescued DHC-induced cell proliferation inhibition. Conclusions: Our results indicated that DHC inhibited cell proliferation and migration/invasion via inactivating MAPK signaling, and showed that DHC might be a potential novel drug to treat malignant melanoma.

Inactivation/deficiency of DHODH induces cell cycle arrest and programed cell death in melanoma.

Malignant melanoma (MM) is one of the most malignant tumors and has a very poor prognosis. However, there are no effective drugs to treat this disease. As a kind of iron flavin dependent enzyme, dihydroorotate dehydrogenase (DHODH, EC 1.3.3.1) is the fourth and a key enzyme in the de novo biosynthesis of pyrimidines. Herein, we found that DHODH inactivation/deficiency inhibited melanoma cell proliferation, induced cell cycle arrest at S phase and lead to autophagy in human melanoma cells. Meanwhile, leflunomide treatment induced cell apoptosis and deficiency of DHODH sensitized cells to drug-induced apoptosis in BCL-2 deficient melanoma cells, while not in BCL-2 abundant melanoma cells. Then we found that BCL-2 could rescue apoptosis induced by DHODH inactivation/deficiency. Moreover, BCL-2 also showed to promote cell cycle arrest and to inhibit autophagy induced by leflunomide. To explore the mechanisms underlying autophagy induced by DHODH inhibition, we found that AMPK-Ulk1 axis was activated in this process. Besides, JNK was phosphorylated and activated to phosphorylate BCL-2, which abrogated the interaction between BCL-2 and Beclin1 and then abolished autophagy. Our findings provided evidences for the potential of DHODH used as a drug target for melanoma treatment.

Comparison of topical anesthesia and subcutaneous infiltration anesthesia with regard to effect of plasma skin regeneration system.

The plasma skin regeneration (PSR) system is a safe device for skin regeneration, which is usually carried out under local anesthetic to control the pain. Topical anesthesia and subcutaneous infiltration anesthesia are the common and safe anesthetizations. This study was undertaken to evaluate the effects of PSR after using topical anesthetization as compared with subcutaneous infiltration anesthesia, thereby inquiring into the effect of subcutaneous infiltration anesthesia in PSR and increasing electivity for clinical work. 14 Sprague Dawley rats were randomly utilized in this experiment. After adequate sedation and depilation, the rat's back was randomly divided into three experimental regions marked as A, B, and C. A and B were treated with lidocaine cream and lidocaine hydrochloride, respectively, before PSR. C was treated solely with PSR without any anesthesia. Biopsies were taken from all treatment sites at 4 and 30 days after treatment to observe the skin necrosis and thickness of new collagen fiber. Histopathologic examination was performed by observers blinded to the treatment conditions. In this analysis, there was a statistically significant reduction (P < 0.01) in the skin necrosis and thickness of new collagen fiber in the topical anesthesia group compared with that in the other two groups, while a statistically significant increase (P < 0.01) in the subcutaneous infiltration anesthesia group. The results suggest that subcutaneous infiltration anesthesia group showed a deeper range of tissue effects via the treatment of PSR as compared with the topical anesthesia and the control groups. Meanwhile, the effect of the topical anesthesia was the lowest. So we conclude that subcutaneous infiltration anesthesia for PSR treatment was superior to that of the topical anesthesia.