Crosstalk with keratinocytes causes GNAQ oncogene specificity in melanoma

Different melanoma subtypes exhibit specific and non-overlapping sets of oncogene and tumor suppressor mutations, despite a common cell of origin in melanocytes. For example, activation of the Gαq/11 signaling pathway is a characteristic initiating event in primary melanomas that arise in the dermis, uveal tract or central nervous system. It is rare in melanomas arising in the epidermis. The mechanism for this specificity is unknown. Here, we present evidence that in the mouse, crosstalk with the epidermal microenvironment actively impairs the survival of melanocytes expressing the GNAQQ209L oncogene. We found that GNAQQ209L, in combination with signaling from the interfollicular epidermis (IFE), stimulates dendrite extension, leads to actin cytoskeleton disorganization, inhibits proliferation and promotes apoptosis in melanocytes. The effect was reversible and paracrine. In contrast, the epidermal environment increased the survival of wildtype and BrafV600E expressing melanocytes. Hence, our studies reveal the flip side of Gaq/11 signaling, which was hitherto unsuspected. In the future, the identification of the epidermal signals that restrain the GNAQQ209L oncogene could suggest novel therapies for GNAQ and GNA11 mutant melanomas.

Targeting Oncogenic Gαq/11 in Uveal Melanoma

Uveal melanoma is the most common intraocular cancer in adults and arises from the transformation of melanocytes in the uveal tract. While treatment of the primary tumor is often effective, 36–50% of patients develop metastatic disease primarily to the liver. While various strategies have been used to treat the metastatic disease, there remain no effective treatments that improve survival. Significant insight has been gained into the pathways that are altered in uveal melanoma, with mutually exclusive activating mutations in the GNAQ and GNA11 genes being found in over 90% of patients. These genes encode the alpha subunits of the hetetrotrimeric G proteins, Gq and G11, and mutations result in activation of several important signaling pathways, including phospholipase C and activation of the transcription factor YAP. In this review, we discuss current efforts to target various signaling pathways in the treatment of uveal melanoma including recent efforts to target Gq and G11 in mouse models. While selective targeting of Gq and G11 provides a potential therapeutic strategy to treat uveal melanoma, it is evident that improved inhibitors and methods of delivery are needed.

The Cellular Composition of the Uveal Immune Environment

The uveal tract consists of the iris, the ciliary body and the choroid; these three distinct tissues form a continuous layer within the eye. Uveitis refers to inflammation of any region of the uveal tract. Despite being grouped together anatomically, the iris, ciliary body and choroid are distinct functionally, and inflammatory diseases may affect only one part and not the others. Cellular structure of tissues direct their function, and understanding the cellular basis of the immune environment of a tissue in health, the “steady state” on which the perturbations of disease are superimposed, is vital to understanding the pathogenesis of those diseases. A contemporary understanding of the immune system accepts that haematopoietic and yolk sac derived leukocytes, though vital, are not the only players of importance. An array of stromal cells, connective tissue cells such as fibroblasts and endothelial cells, may also have a role in the inflammatory reaction seen in several immune-mediated diseases. In this review we summarise what is known about the cellular composition of the uveal tract and the roles these disparate cell types have to play in immune homeostasis. We also discuss some unanswered questions surrounding the constituents of the resident leukocyte population of the different uveal tissues, and we look ahead to the new understanding that modern investigative techniques such as single cell transcriptomics, multi-omic data integration and highly-multiplexed imaging techniques may bring to the study of the uvea and uveitis, as they already have to other immune mediated inflammatory diseases.

Ocular manifestations in patients who underwent COVID-19 in the early stages after Phaco surgery with implantation of IOL

Purpose. To study the ocular manifestations in patients with pseudophakia who underwent COVID-19 during the rehabilitation period after surgery. Material and methods. 46 patients with Phaco with implantation of IOL who underwent COVID-19 in the period from 1 week to 2 months after surgery. Of the examined patients, there were 28 men (61%), 18 women (391%). The average age of the patients was 63±1,2 years. Results. In 78% of cases, vascular pathology of the anterior and posterior segments of the eyeball was observed in patients who underwent COVID-19 in the early postoperative period after Phaco with implantation of IOL. Conclusions. The main ocular symptoms from the anterior segment of the eyeball in patients in 17% of cases were the occurrence or intensification of previously existing manifestations of the «dry eye» syndrome, as well as inflammatory phenomena from the anterior part of the uveal tract. From the posterior segment of the eye, in 70% of cases, there was a progression of vascular disorders, as well as the appearance of complications associated with manifestations of hypercoagulation syndrome and systemic vasculopathy. Key words: Covid-19, cataract phacoemulsification, pseudophakia.

LAG3 and Its Ligands Show Increased Expression in High-Risk Uveal Melanoma

Uveal melanoma (UM) is a rare ocular malignancy which originates in the uveal tract, and often gives rise to metastases. Potential targets for immune checkpoint inhibition are lymphocyte-activation gene 3 (LAG3) and its ligands. We set out to analyse the distribution of these molecules in UM. The expression of mRNA was determined using an Illumina array in 64 primary UM from Leiden. The T lymphocyte fraction was determined by digital droplet PCR. In a second cohort of 15 cases from Leiden, mRNA expression was studied by Fluidigm qPCR, while a third cohort consisted of 80 UM from TCGA. In the first Leiden cohort, LAG3 expression was associated with the presence of epithelioid cells (p = 0.002), monosomy of chromosome 3 (p = 0.004), and loss of BAP1 staining (p = 0.001). In this Leiden cohort as well as in the TCGA cohort, LAG3 expression correlated positively with the expression of its ligands: LSECtin, Galectin-3, and the HLA class II molecules HLA-DR, HLA-DQ, and HLA-DP (all p < 0.001). Furthermore, ligands Galectin-3 and HLA class II were increased in monosomy 3 tumours and the expression of LAG3 correlated with the presence of an inflammatory phenotype (T cell fraction, macrophages, HLA-A and HLA-B expression: all p < 0.001). High expression levels of LAG3 (p = 0.01), Galectin-3 (p = 0.001), HLA-DRA1 (p = 0.002), HLA-DQA1 (p = 0.04), HLA-DQB2 (p = 0.03), and HLA-DPA1 (p = 0.007) were associated with bad survival. We conclude that expression of the LAG ligands Galectin-3 and HLA class II strongly correlates with LAG3 expression and all are increased in UM with Monosomy 3/BAP1 loss. The distribution suggests a potential benefit of monoclonal antibodies against LAG3 or Galectin-3 as adjuvant treatment in patients with high-risk UM.

Crosstalk with keratinocytes causes GNAQ oncogene specificity in melanoma

Different melanoma subtypes exhibit specific and non-overlapping sets of oncogene and tumor suppressor mutations, despite a common cell of origin in melanocytes. For example, activation of the Gαq/11 signaling pathway is a characteristic initiating event in primary melanomas that arise in the dermis, uveal tract or central nervous system. It is rare in melanomas arising in the epidermis. Here, we present evidence that in the mouse, crosstalk with the epidermal microenvironment actively impairs the survival of melanocytes expressing the GNAQQ209L oncogene, providing a new model for oncogene specificity in cancer. The presence of epidermal cells inhibited cell division and fragmented dendrites of melanocytes expressing GNAQQ209L in culture, while they promoted the growth of normal melanocytes. Differential gene expression analysis of FACS sorted epidermal melanocytes showed that cells expressing GNAQQ209L exhibit an oxidative stress and apoptosis signature previously linked to vitiligo. Furthermore, PLCB4, the direct downstream effector of Gαq/11 signaling, is frequently mutated in cutaneous melanoma alongside P53 and NF1. Our results suggest that a deficiency of PLCB4 promotes cutaneous melanomagenesis by reducing GNAQ driven signaling. Hence, our studies reveal the flip side of the GNAQ/PLCB4 signaling pathway, which was hitherto unsuspected. In the future, understanding how epidermal crosstalk restrains the GNAQQ209L oncogene could suggest novel melanoma therapies.

External Beam Radiation Therapy for Metastatic Tumor to the Iris: A Case Report and Brief Literature Review

Tumor metastases involving the iris are rare and represent about 3% of metastases to the uveal tract. The typical presentation is a patient with a known history of carcinoma who develops blurry vision, ocular pain, and/or eye redness, which may be erroneously diagnosed as uveitis. In this case, we report the workup, diagnosis, and treatment of a 76 year old man with a history of node negative multi-focal adenocarcinoma of the lung who was found to have a left iris metastasis. He presented with blurry vision and left eye pain. Exam revealed a 7 x 7 mm amelanotic ciliary body mass, which was ultimately biopsied and found to be consistent with his lung primary. He was treated with external beam radiation therapy, 3000cGy in 10 fractions, to the left globe. His three and nine-month follow up MRIs showed good treatment response and he is clinically without disease progression. EBRT is a safe and effective modality for the treatment of iris metastases.

Nepafenac loaded ophthalmic nanocarriers for treatment of uveitis: A review

Visual impairment (VI), a worldwide worry that is probably going to raise with delayed futures, has gained increasing attention in the domain of eye care. Now a days, new cases of visual impairment occur in older individuals, some children are born with visual impairments resulting from retinopathy of prematurity, a condition associated with premature birth. Other children experience vision loss because of congenital glaucoma or congenital cataracts, Uveitis and some experience vision loss of unknown etiology. Uveitis is an intraocular inflammation involving primarily the uveal tract. Vision is one of our most cherished senses. There are nearly 45 million people worldwide who are blind and a further 135 million people are visually disabled. Uveitis causes 0.6% - 11% of blindness in various studies. The ophthalmic preparations are available as buffered, sterile and isotonic solution. For the ocular delivery of drugs, several types of dosage forms are prepared and marketed. As drops are easier to administer so the most prescribed dosage form is the eye drop solution. Nepafenac is unique among ophthalmic NSAIDs in that it is a prodrug deaminated to amfenac, a highly effective non-selective cyclooxygenase inhibitor. The compiled data presented in this review will act as a good information resource and reference point for further research in the field of ocular drug delivery aiming non-invasive sustained release of drugs in the anterior and posterior segments of the eye.