Prognostic impact of HERC2 protein and pink-eyed dilution protein in uveal melanoma

Deciphering the intricate relationship between macrophages, pigmentation, and prognosis in uveal melanoma

High pigmentation and the abundance of M2 macrophages have been identified as negative predictors in uveal melanoma (UM). Risk factors associated with UM that are prevalent in high-risk white populations are still present, though less common, in relatively low-risk Asian population. Research shows that proangiogenic M2 macrophages and monosomy 3 play a significant role in UM progression. Our aim is to investigate the impact of tumor-associated macrophages in UM and examine their correlation with monosomy 3 & pigmentation. TEM was used to analyze the morphology of macrophages in UM. Forty UM samples underwent FISH for monosomy 3 identification. Immunohistochemistry was done to assess M2/M1 macrophages on 82 UM tissue samples. IL-10 and IL-12 expression was quantified in UM serum samples by ELISA. Expression of all markers was correlated with pigmentation markers (TYRP1, TYRP2, SILV & MITF). Prognostic outcomes were determined using the Cox proportional hazard model & log-rank test. Increased expression of M2/M1 macrophages was observed in 31 UM cases, which correlated with high expression of pigmentation markers. IL-10 concentration was high in UM cases. Monosomy 3 was evident in 50% of UM cases and significantly associated with increased immunoexpression of M2/M1 macrophages and pigmentation markers. Reduced MFS was observed in UM patients with high M2/M1 macrophage expression (p=0.001). High pigmentation and increased M2 macrophage density could impact the tumor microenvironment in UM. This could contribute to ineffective antitumor immune responses in UM patients. Our findings suggest avenues for developing novel therapeutic approaches to counteract these immunosuppressive effects in UM.

Prognostic significance of melanogenesis pathway and its association with the ultrastructural characterisation of melanosomes in uveal melanoma

BACKGROUND

Pigmentation could be a relevant prognostic factor in uveal melanoma (UM) development. Microphthalmia-associated transcription factor (MITF) regulates melanin synthesis by activating tyrosinase-related protein 2 (TYRP2) and silver protein (SILV) that induce the melanogenesis pathway. Although their oncogenic potential has been observed in various malignancies but has not been investigated in UM Asian population. Our aim is to study the ultrastructure of melanosomes and the prognostic significance of pigmentation markers such as TYRP2, MITF and SILV in UM.

METHODS

Transmission electron microscopy was performed to compare the ultrastructure of melanosomes in the normal choroid and UM cases. Immunoexpression of TYRP2, SILV and MITF was analysed in 82 UM samples. The mRNA expression level of all genes was measured in 70 UM cases. A statistical correlation was performed to determine the prognostic significance of all markers.

RESULTS

Premelanosomes and mature melanosomes undergoing dedifferentiation were observed in high-pigmented UM cases as compared with low-pigmented UM cases. Seventy per cent of UM cases showed high SILV expression while TYRP2 and MITF expression was present in 58% and 56% of cases, respectively. At the mRNA level, upregulation of TYRP2, SILV and MITF markers was seen in around 50% of UM cases, which was statistically significant with high pigmentation. Reduced metastatic-free survival was statistically significant with the MITF protein expression.

CONCLUSION

Our results demonstrated that ultrastructural changes in melanosomes and high expression of TYRP2, MITF and SILV could dysregulate the melanogenesis pathway and might be responsible for the aggressive behaviour of UM.

HERC2 promotes inflammation-driven cancer stemness and immune evasion in hepatocellular carcinoma by activating STAT3 pathway

BACKGROUND

Hepatic inflammation is a common initiator of liver diseases and considered as the primary driver of hepatocellular carcinoma (HCC). However, the precise mechanism of inflammation-induced HCC development and immune evasion remains elusive and requires extensive investigation. This study sought to identify the new target that is involved in inflammation-related liver tumorigenesis.

METHODS

RNA-sequencing (RNA-seq) analysis was performed to identify the differential gene expression signature in primary human hepatocytes treated with or without inflammatory stimulus. A giant E3 ubiquitin protein ligase, HECT domain and RCC1-like domain 2 (HERC2), was identified in the analysis. Prognostic performance in the TCGA validation dataset was illustrated by Kaplan-Meier plot. The functional role of HERC2 in HCC progression was determined by knocking out and over-expressing HERC2 in various HCC cells. The precise molecular mechanism and signaling pathway networks associated with HERC2 in HCC stemness and immune evasion were determined by quantitative real-time PCR, immunofluorescence, western blot, and transcriptomic profiling analyses. To investigate the role of HERC2 in the etiology of HCC in vivo, we applied the chemical carcinogen diethylnitrosamine (DEN) to hepatocyte-specific HERC2-knockout mice. Additionally, the orthotopic transplantation mouse model of HCC was established to determine the effect of HERC2 during HCC development.

RESULTS

We found that increased HERC2 expression was correlated with poor prognosis in HCC patients. HERC2 enhanced the stemness and PD-L1-mediated immune evasion of HCC cells, which is associated with the activation of signal transducer and activator of transcription 3 (STAT3) pathway during the inflammation-cancer transition. Mechanically, HERC2 coupled with the endoplasmic reticulum (ER)-resident protein tyrosine phosphatase 1B (PTP1B) and limited PTP1B translocation from ER to ER-plasma membrane junction, which ameliorated the inhibitory role of PTP1B in Janus kinase 2 (JAK2) phosphorylation. Furthermore, HERC2 knockout in hepatocytes limited hepatic PD-L1 expression and ameliorated HCC progression in DEN-induced mouse liver carcinogenesis. In contrast, HERC2 overexpression promoted tumor development and progression in the orthotopic transplantation HCC model.

CONCLUSION

Our data identified HERC2 functions as a previously unknown modulator of the JAK2/STAT3 pathway, thereby promoting inflammation-induced stemness and immune evasion in HCC.

Novel Prognostic Immunohistochemical Markers in Uveal Melanoma-Literature Review

Simple Summary

The following study provides an overview of the English-language literature on the search for new prognostic factors for uveal melanoma. Uveal melanoma is the most common primary intraocular tumor in adults, and although it is a relatively rare disease, it poses a significant health problem. About half of the patients develop distant metastases, and unfortunately there are currently no effective treatments for the disease at such an advanced stage. The search for new prognostic factors is important to understand the biology of the disease and to be able to monitor patients more effectively. At the same time, it creates an opportunity to find new therapeutic targets. We focused our attention on immunohistochemical research because it is a widely used method, relatively cheap, technically simple, and gives reproducible results. The analysis of this study will enable other researchers to verify their research plans and may also be a source of inspiration for creating new ones.

Abstract

Uveal melanoma is the most common primary intraocular neoplasm in adults. As there are currently no effective methods of treating the disease in the metastatic stage, there is a need to search for new prognostic factors that would enable a reliable assessment of the patient’s condition and constitute a possible therapeutic target. In this review, we have prepared the results of English-language studies on new prognostic factors determined with immunohistochemical methods. We found 64 articles in which the expression of various proteins was associated in a statistically significant manner with the histopathological and clinical prognostic factors identified by AJCC. The results of our work clearly show that the biology of uveal melanoma is extraordinarily complex. Numerous studies have shed new light on the complexity of the processes involved in the development of this cancer. Moreover, a careful analysis of the expression of individual proteins may allow the identification of homogeneous groups of patients requiring different treatment regimens.

Association of TYRP1 with hypoxia and its correlation with patient outcome in uveal melanoma

PURPOSE

Molecular mechanisms of uveal melanoma development in association with high pigmentation are unclear. Tyrosinase Related Protein (TYRP1) is not only one of the important melanogenesis marker that contributes to melanin synthesis, but can also prevents the melanocyte death. The induction of melanogenesis leads to induction of HIF-1α which can affect the behavior of melanoma cells and its surrounding environment. The aim of our study was to determine the expression of TYRP1 and HIF-1α at the protein and RNA level and determine its prognostic significance.

METHODS

In the present study, the expression of TYRP1 and HIF-1α was investigated on 61 formalin-fixed paraffin-embedded choroidal melanoma samples by immunohistochemistry. Fresh 50 samples were validated by real-time PCR. Results were correlated with clinicopathological parameters and Kaplan-Meier was performed to determine the prognostic significance.

RESULTS

High immunoexpression of TYRP1 and HIF-1α was present in 61 and 54% of patients, respectively. Both TYRP1 and HIF-1α correlated well with high pigmentation and BAP1 (BRCA1 Associated Protein-1) loss (p < 0.05) at IHC level as well as transcriptional level. There was reduced metastatic free survival in patients with necrosis and this was statistically significant (p = 0.010).

CONCLUSION

Our findings indicate that TYRP1 can be used as a potential biomarker in the development of targeted therapy in UM. Further studies on melanogenesis markers associated with TYRP1 could provide us a better understanding in this field.