Oncogenic GNAQ and GNA11 mutations in uveal melanoma in Chinese

Design, synthesis and evaluation of quinazoline derivatives as Gαq/11 proteins inhibitors against uveal melanoma

Uveal melanoma (UM) represents the predominant ocular malignancy among adults, exhibiting high malignancy and proclivity for liver metastasis. GNAQ and GNA11 encoding Gαq and Gα11 proteins are key genes to drive UM, making the selective inhibition of Gαq/11 proteins to be a potential therapeutic approach for combating UM. In this study, forty-six quinazoline derivatives were designed, synthesized, and assessed for their ability to inhibit Gαq/11 proteins and UM cells. Compound F33 emerged as the most favorable candidate, and displayed moderate inhibitory activity against Gαq/11 proteins (IC50 = 9.4 μM) and two UM cell lines MP41 (IC50 = 6.7 μM) and 92.1 (IC50 = 3.7 μM). Being a small molecule inhibitor of Gαq/11 proteins, F33 could effectively suppress the activation of downstream signaling pathways in a dose-dependent manner, and significantly inhibits UM in vitro.F33 represents a promising lead compound for developing therapeutics for UM by targeting Gαq/11 proteins.

Molecular profiling of primary uveal melanoma: results of a Polish cohort

There is no published data regarding the molecular alterations of Polish patients with primary uveal melanoma. We performed whole exome sequencing of 20 primary uveal melanomas (UMs), 10 metastasizing and 10 non-metastasizing cases to identify significant molecular alterations. We detected mutations and copy number variants in the BAP1 gene in 50% (10 cases) of the cases. GNA11 mutations were detected in 50% (10 cases) including nine p.Q209L and one p.R183C. GNAQ mutations gene were detected in 40% (8 cases) and all were p.Q209P. SF3B1, EIF1AX, PLCB4 , and PALB2 mutations were detected in one case each. Genetic aberrations of FBXW7 were detected in 55% of cases, with copy number loss of 10 and missense mutation in one. Gain or loss of copy number was observed in 60%, 60%, and 10% of cases in MYC, MLH1 , and CDKN2A genes, respectively. BAP1 and GNAQ tumor suppressor genes are more often mutated in UM with metastasis, while GNA11 mutations are more frequently detected in non-metastasizing tumors. MYC copy gain was present twice as frequently (80% versus 40%) in cases with versus those without metastases. BAP1 mutation correlated with worse overall survival; while GNA11 mutation and CDKN2A loss correlated with better and worse progression-free survival, respectively. We have confirmed BAP1 prognostic potential and documented frequent MYC amplification in metastasizing cases. Although GNA11 mutation and CDKN2A loss significantly correlated with progression-free survival in our study, our sample size is small. The prognostic significance of GNAQ/GNA11 mutation and CDKN2A loss would require further investigation.

GNAQ and GNA11 Genes: A Comprehensive Review on Oncogenesis, Prognosis and Therapeutic Opportunities in Uveal Melanoma

The GNAQ and GNA11 genes are mutated in almost 80–90% of uveal melanomas in a mutually exclusive pattern. These genes encode the alpha subunits of the heterotrimeric G proteins, Gq and G11; thus, mutations of these genes result in the activation of several important signaling pathways, including phospholipase C, and activation of the transcription factor YAP. It is well known that both of them act as driver genes in the oncogenic process and it has been assumed that they do not play a role in the prognosis of these tumours. However, it has been hypothesised that mutations in these genes could give rise to molecularly and clinically distinct types of uveal melanomas. It has also been questioned whether the type and location of mutation in the GNAQ and GNA11 genes may affect the progression of these tumours. All of these questions, except for their implications in carcinogenesis, remain controversial. Uveal melanoma has a distinctive genetic profile, and specific recurrent mutations, which make it a potential candidate for treatment with targeted therapy. Given that the most frequent mutations are those observed in the GNAQ and GNA11 genes, and that both genes are involved in oncogenesis, these molecules, as well as the downstream signalling pathways in which they are involved, have been proposed as promising potential therapeutic targets. Therefore, in this review, special attention is paid to the current data related to the possible prognostic implications of both genes from different perspectives, as well as the therapeutic options targeting them.

Clinical features and survival outcomes of ocular melanoma in a multi-ethnic Asian cohort

Ocular melanomas are uncommon cancers in Southeast Asia unlike in the West. We conducted a retrospective review of patients (n = 44) with histologically-proven ocular melanoma within a multi-ethnic Asian cohort from Singapore. Clinicopathological features and relapse patterns were examined, and survival outcomes of interest included recurrence-free survival (RFS) and overall survival (OS). Survival analysis was performed using the Kaplan–Meier method and multivariable Cox proportional regression. The study cohort included 18 male and 26 female patients, with a median age of 52 years (range 8–78). Median follow-up was 154 months. For uveal melanomas (n = 29), the 5-year RFS and OS was 56.8% and 76.6%, respectively; whilst for conjunctival melanomas (n = 15), the 5-year RFS and OS was 30.1% and 68.8%, respectively. Fifteen patients (38.5%) eventually developed metastasis, following which the median survival was only 17 months. Multivariate analysis demonstrated that higher T stage was a significant independent predictor for both OS (HR 8.69, 95% CI 1.03 to 73.09, p = 0.047) and RFS (HR 11.62, 95% CI 2.45 to 55.00, p = 0.002). Smoking history was independently predictive of better RFS (HR 0.08, 95% CI 0.01 to 0.78, p = 0.030). In conclusion, our study demonstrates the poor ocular melanoma outcomes in Southeast Asians, highlighting the necessity for urgent research in this area of unmet clinical need.

Heterogeneity of GNAQ/11 mutation inversely correlates with the metastatic rate in uveal melanoma

PURPOSE

To determine whether the GNAQ/11 mutation correlated with the outcome of patients with uveal melanoma (UM) when genetic heterogeneity was considered.

METHODS

We performed a retrospective study of sixty-seven patients with UM. The heterogeneity of GNAQ/11 was examined by using droplet digital PCR. The correlation between metastasis and heterogeneity of the GNAQ/11 mutation was analysed. Disease free survival curves were constructed using the Kaplan-Meier method, and the Wilcoxon log-rank test was used to compare the curves.

RESULTS

The GNAQ/11 mutation ratio was varied between each case. Among these patients, 28.35% of them harboured homogeneous mutation of GNAQ/11, 62.69% present heterogeneous mutation and 8.96% didn't present either GNAQ or GNA11 mutation. The tumour with heterogeneous mutation of GNAQ/11 has a higher metastatic rate than that with homogeneous mutation (13/29 vs 1/18, p=0.027). In Kaplan-Meier analysis, metastasis-free survival was not significantly associated with either homogeneous or heterogeneous mutation of GNAQ/11.

CONCLUSION

The mutation ratio of GNAQ/11 in UM was quite variable. The tumour with heterogeneous mutation of GNAQ/11 is more likely to develop a poor prognosis than that with homogeneous mutation of GNAQ/11.

The Role of Mutation Rates of GNAQ or GNA11 in Cases of Uveal Melanoma in Japan

GNAQ and GNA11 mutations are thought to be important for the tumorigenesis of uveal melanoma. Although previous studies have reported on mutation rates in cases of uveal melanoma, presently, no such report for the Japanese population exists. In this study, we examined the frequency of GNAQ and GNA11 somatic mutations in cases of uveal melanoma in Japan and their relationship with clinicopathologic features or Ki-67-positive cell rates (Ki-67 labeling index: Ki-67 LI) using immunofluorescence methods. The study involved 19 cases of uveal melanoma. We extracted the template DNA from formalin-fixed, paraffin-embedded specimens using a DNA extraction kit. We amplified the DNA sequences of GNAQ and GNA11 using polymerase chain reaction and analyzed mutations by direct sequencing. We evaluated Ki-67 LI using immunofluorescence methods. The frequencies of GNAQ and GNA11 somatic mutations were 26.3% (5/19) and 31.6% (6/19), respectively. The GNAQ and GNA11 mutations were mutually exclusive, as indicated in previous reports. The frequency of GNA11 mutations was significantly higher in epithelioid cells; however, no significant association between GNAQ mutations and cell type was evident, and there was no significant difference in Ki-67 LI between the mutation-positive and mutation-negative tumors. GNAQ and GNA11 mutations were identified in cases of uveal melanoma in Japan, although at lower frequencies than in white counterparts. The mutation frequency of GNA11 was significantly higher in epithelioid cells.

Clinical spectrum, treatment and outcomes of uveal melanoma in a tertiary centre

INTRODUCTION

We aimed to describe the clinical characteristics, diagnostic challenges, treatment patterns and outcomes of uveal melanoma (UM) in a tertiary care centre.

METHODS

This is a retrospective case series of 11 consecutive patients with UM who were managed in a tertiary referral centre between 2002 and 2017. Epidemiological, clinical, pathological and radiological characteristics were reviewed. Classification of choroidal melanoma as small, medium or large was based on the criteria established by the Collaborative Ocular Melanoma Study.

RESULTS

Mean age at presentation was 42.9 (range 27‒67) years. In 7 (64%) patients, a definitive diagnosis of UM was made after a mean follow-up period of 6.4 (range 1‒17) months. There were one, six and four patients with small-, medium- and large-sized choroidal melanomas, respectively. Treatment was enucleation in 5 (45.5%) patients, plaque brachytherapy in 4 (36.4%) patients, transpupillary thermotherapy in 1 (9.1%) patient, and observation in 1 (9.1%) patient. Median follow-up was 29 months. Metastatic disease developed in 5 (45.5%) patients at the mean age of 46.6 (range 38‒56) years, with median overall survival of 20 months. Genetic mutations in three patients were monosomy 3 (n = 2), and gain of 3q and 8q (n = 1).

CONCLUSION

Our study supports the finding that UM in Chinese and Asian Indian patients presents at a younger age than in Caucasians. Although it is rare, ophthalmologists should remain mindful of this life-threatening disease. We propose establishing a national and regional registry for ocular tumours with genetic information to characterise the disease spectrum in Southeast Asia.

Prognostic value of chromosomal imbalances, gene mutations, and BAP1 expression in uveal melanoma

Uveal melanoma (UM) exhibits recurring chromosomal abnormalities and gene driver mutations, which are related to tumor evolution/progression. Almost half of the patients with UM develop distant metastases, predominantly to the liver, and so far there are no effective adjuvant therapies. An accurate UM genetic profile could assess the individual patient's metastatic risk, and provide the basis to determine an individualized targeted therapeutic strategy for each UM patient. To investigate the presence of specific chromosomal and gene alterations, BAP1 protein expression, and their relationship with distant progression free survival (DPFS), we analyzed tumor samples from 63 UM patients (40 men and 23 women, with a median age of 64 years), who underwent eye enucleation by a single cancer ophthalmologist from December 2005 to June 2016. UM samples were screened for the presence of losses/gains in chromosomes 1p, 3, 6p, and 8q, and for mutations in GNAQ, GNA11, BAP1, SF3B1, and EIF1AX. BAP1 protein expression was detected by immunohistochemistry (IHC). Multivariate analysis showed that the presence of monosomy 3, 8q gain, and loss of BAP1 protein were significantly associated to DPFS, while BAP1 gene mutation was not, mainly due to the presence of metastatic UM cases with negative BAP1 IHC and no BAP1 mutation detected by Sanger sequencing. Loss of BAP1 protein expression and monosomy 3 represent the strongest predictors of metastases, and may have important implications for implementation of patient surveillance, properly designed clinical trials enrollment, and adjuvant therapy.

CUT-PCR: CRISPR-mediated, ultrasensitive detection of target DNA using PCR

Circulating tumor DNA (ctDNA) has emerged as a tumor-specific biomarker for the early detection of various cancers. To date, several techniques have been devised to enrich the extremely small amounts of ctDNA present in plasma, but they are still insufficient for cancer diagnosis, especially at the early stage. Here, we developed a novel method, CUT (CRISPR-mediated, Ultrasensitive detection of Target DNA)-PCR, which uses CRISPR endonucleases to enrich and detect the extremely small amounts of tumor DNA fragments among the much more abundant wild-type DNA fragments by specifically eliminating the wild-type sequences. We computed that by using various orthologonal CRISPR endonucleases such as SpCas9 and FnCpf1, the CUT-PCR method would be applicable to 80% of known cancer-linked substitution mutations registered in the COSMIC database. We further verified that CUT-PCR together with targeted deep sequencing enables detection of a broad range of oncogenes with high sensitivity (<0.01%) and accuracy, which is superior to conventional targeted deep sequencing. In the end, we successfully applied CUT-PCR to detect sequences with oncogenic mutations in the ctDNA of colorectal cancer patients’ blood, suggesting that our technique could be adopted for diagnosing various types of cancer at early stages.

Racial Differences in Cancer Susceptibility and Survival: More Than the Color of the Skin?

Epidemiological studies point to race as a determining factor in cancer susceptibility. In US registries recording cancer incidence and survival by race (distinguishing 'black versus white'), individuals of African ancestry have a globally increased risk of malignancies compared with Caucasians and Asian Americans. Differences in socioeconomic status and health-care access play a key role. However, the lesser disease susceptibility of Hispanic populations with comparable lifestyles and socioeconomic status as African Americans (Hispanic paradox) points to the concomitant importance of genetic determinants. Here, we overview the molecular basis of racial disparity in cancer susceptibility ranging from genetic polymorphisms and cancer-driver gene mutations to obesity, chronic inflammation, and immune responses. We discuss implications for race-adapted cancer screening programs and clinical trials to reduce disparities in cancer burden.

The biology of uveal melanoma

Uveal melanoma (UM), a rare cancer of the eye, is distinct from cutaneous melanoma by its etiology, the mutation frequency and profile, and its clinical behavior including resistance to targeted therapy and immune checkpoint blockers. Primary disease is efficiently controlled by surgery or radiation therapy, but about half of UMs develop distant metastasis mostly to the liver. Survival of patients with metastasis is below 1 year and has not improved in decades. Recent years have brought a deep understanding of UM biology characterized by initiating mutations in the G proteins GNAQ and GNA11. Cytogenetic alterations, in particular monosomy of chromosome 3 and amplification of the long arm of chromosome 8, and mutation of the BRCA1-associated protein 1, BAP1, a tumor suppressor gene, or the splicing factor SF3B1 determine UM metastasis. Cytogenetic and molecular profiling allow for a very precise prognostication that is still not matched by efficacious adjuvant therapies. G protein signaling has been shown to activate the YAP/TAZ pathway independent of HIPPO, and conventional signaling via the mitogen-activated kinase pathway probably also contributes to UM development and progression. Several lines of evidence indicate that inflammation and macrophages play a pro-tumor role in UM and in its hepatic metastases. UM cells benefit from the immune privilege in the eye and may adopt several mechanisms involved in this privilege for tumor escape that act even after leaving the niche. Here, we review the current knowledge of the biology of UM and discuss recent approaches to UM treatment.

Uveal melanoma: epidemiology, etiology, and treatment of primary disease

Uveal melanoma (UM) is the most common intraocular malignancy and arises from melanocytes in the iris, ciliary body, or choroid. Early diagnosis and local treatment is crucial, as survival correlates with primary tumor size. However, approximately 50% of patients will develop metastatic disease with 6-12 months' survival from metastatic diagnosis. Genomic analyses have led to the development of gene-expression profiles that effectively predict metastatic progression; unfortunately, no adjuvant therapy has been shown to prolong survival to date. New insights into the molecular biology of UM have found frequent activating mutations in genes encoding for the G-protein α-subunit, GNAQ and GNA11, and improved understanding of the downstream signaling pathways MAPK, PI3K/Akt, and Hippo have afforded an array of new targets for treatment of this disease. Studies are under way with rationally developed regimens targeting these pathways, and novel agents are under development. We review the diagnosis, management, and surveillance of primary UM and the adjuvant therapy trials under way.

Clinicopathological Characteristics and Prognosis for Survival after Enucleation of Uveal Melanoma in Chinese Patients: Long-term Follow-up

PURPOSE

To summarize the clinicopathological characteristics and prognosis of uveal melanoma (UM) after enucleation in Chinese patients.

METHODS

Between 2003 and 2012, a series of 171 patients with UM received enucleation at the Eye & ENT Hospital of Fudan University in Shanghai. Patient clinical information was collected. Pathological examination and BAP1 staining of the enucleated eyes were conducted. Univariate and multivariate Cox proportional hazard regressions were conducted to determine the risk factors, and the survival rates were calculated and compared.

RESULTS

The study included 83 (49%) men and 88 (51%) women, with a mean age of 48.6 years. The mean largest basal tumor diameter and mean largest tumor thickness were 11.8 and 8.6 mm, respectively. Ciliary body involvement was observed in 19 tumors (11%). Spindle and nonspindle patterns were observed in 100 (58%) and 71 eyes (42%), respectively. Extrascleral extension was observed in three eyes (2%). BAP1 staining was negative in 34% (53/156) of all tumors and 53% (19/36) of the cases with melanoma-related metastasis. The mean follow-up period was 63.4 months for all patients with the exception of 11 patients, who were excluded because they were lost during follow-up. A large basal tumor diameter, ciliary body involvement, nonspindle cell type, extrascleral extension, and negative BAP1 staining were associated with a worse prognosis. The survival curves significantly differed between the BAP1-negative and BAP1-positive groups (P = 0.004). According to Kaplan-Meier analysis, the 5- and 10-year metastasis-free survival rates were 80% and 70%, respectively.

CONCLUSIONS

A large basal tumor diameter, ciliary body involvement, nonspindle cell type, extrascleral extension, and negative BAP1 staining may be risk factors for the prediction of the UM prognosis. A younger age at diagnosis and a similar prognosis between genders may be unique features in Asian patients compared to the Caucasian population.