Exploring cancer in LRRK2 mutation carriers and idiopathic Parkinson's disease

Impact of Parkinson's disease diagnosis validity on the association with cancer: A systematic review and meta-analysis

BACKGROUND

Meta-analyses have reported lower cancer incidence in patients with Parkinson's disease (PD) compared to the general population but with considerable data heterogeneity.

OBJECTIVE

To explore how the validity of the PD diagnoses is related to the association with cancer.

METHODS

We conducted a systematic review and meta-analysis in which studies were stratified into groups based on the diagnostic validity of Parkinson's disease. Studies investigating mortality data and those examining cancer risk within certain genetic subgroups of PD were excluded.

RESULTS

Thirty-four articles encompassing 533,102 patients with PD from 11 countries met the inclusion criteria. Stratified analyses revealed no association between PD and overall cancer risk preceding or following the PD diagnosis in studies using validated PD data. Studies utilizing less robust PD identification methods, the majority of which were cohort studies, demonstrated a neutral or decreased cancer risk among PD patients. In the studies with the most rigorous PD validation organ-specific analyses showed an increased risk of cutaneous melanoma but no decreased risk in any type of cancer. The positive association between PD and melanoma was more pronounced in the studies with more robust PD diagnosis validity.

CONCLUSIONS

The reported associations between PD and cancer are substantially influenced by the quality of PD data. Future investigations should concentrate on organ-specific cancers, instead of pooling cancers together, and use only PD cohorts with validated diagnosis.

Epidemiology of Parkinson's Disease: An Update

PURPOSE OF REVIEW

In recent decades, epidemiological understanding of Parkinson disease (PD) has evolved significantly. Major discoveries in genetics and large epidemiological investigations have provided a better understanding of the genetic, behavioral, and environmental factors that play a role in the pathogenesis and progression of PD. In this review, we provide an epidemiological update of PD with a particular focus on advances in the last five years of published literature.

RECENT FINDINGS

We include an overview of PD pathophysiology, followed by a detailed discussion of the known distribution of disease and varied determinants of disease. We describe investigations of risk factors for PD, and provide a critical summary of current knowledge, knowledge gaps, and both clinical and research implications. We emphasize the need to characterize the epidemiology of the disease in diverse populations. Despite increasing understanding of PD epidemiology, recent paradigm shifts in the conceptualization of PD as a biological entity will also impact epidemiological research moving forward and guide further work in this field.

Leveraging genetic diversity to understand monogenic Parkinson's disease's landscape in AfrAbia

Parkinson's disease may be caused by a single highly deleterious and penetrant pathogenic variant in 5-10% of cases (monogenic). Research into these mutational disorders yields important pathophysiological insights. This article examines the phenotype, genotype, pathophysiology, and geographic and ethnic distribution of genetic forms of disease. Well established Parkinson's disease (PD) causal variants can follow an autosomal dominant (SNCA, LRRK2, and VPS35) and autosomal recessive pattern of inheritance (PRKN, PINK1, and DJ). Parkinson's disease is a worldwide condition, yet the AfrAbia population is understudied in this regard. No prevalence or incidence investigations have been conducted yet. Few studies on genetic risk factors for PD in AfrAbia communities have been reported which supported the notion that the prevalence and incidence rates of PD in AfrAbia are generally lower than those reported for European and North American populations. There have been only a handful of documented genetic studies of PD in AfrAbia and very limited cohort and case-control research studies on PD have been documented. In this article, we provide a summary of prior conducted research on monogenic PD in Africa and highlight data gaps and promising new research directions. We emphasize that monogenic Parkinson's disease is influenced by distinctions in ethnicity and geography, thereby reinforcing the need for global initiatives to aggregate large numbers of patients and identify novel candidate genes. The current article increases our knowledge of the genetics of Parkinson's disease (PD) and helps to further our knowledge on the genetic factors that contribute to PD, such as the lower penetrance and varying clinical expressivity of known genetic variants, particularly in AfrAbian PD patients.

Investigation of Shared Genetic Risk Factors Between Parkinson's Disease and Cancers

BACKGROUND

Epidemiological studies that examined the association between Parkinson's disease (PD) and cancers led to inconsistent results, but they face a number of methodological difficulties.

OBJECTIVE

We used results from genome-wide association studies (GWASs) to study the genetic correlation between PD and different cancers to identify common genetic risk factors.

METHODS

We used individual data for participants of European ancestry from the Courage-PD (Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease; PD, N = 16,519) and EPITHYR (differentiated thyroid cancer, N = 3527) consortia and summary statistics of GWASs from iPDGC (International Parkinson Disease Genomics Consortium; PD, N = 482,730), Melanoma Meta-Analysis Consortium (MMAC), Breast Cancer Association Consortium (breast cancer), the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (prostate cancer), International Lung Cancer Consortium (lung cancer), and Ovarian Cancer Association Consortium (ovarian cancer) (N comprised between 36,017 and 228,951 for cancer GWASs). We estimated the genetic correlation between PD and cancers using linkage disequilibrium score regression. We studied the association between PD and polymorphisms associated with cancers, and vice versa, using cross-phenotypes polygenic risk score (PRS) analyses.

RESULTS

We confirmed a previously reported positive genetic correlation of PD with melanoma (Gcorr = 0.16 [0.04; 0.28]) and reported an additional significant positive correlation of PD with prostate cancer (Gcorr = 0.11 [0.03; 0.19]). There was a significant inverse association between the PRS for ovarian cancer and PD (odds ratio [OR] = 0.89 [0.84; 0.94]). Conversely, the PRS of PD was positively associated with breast cancer (OR = 1.08 [1.06; 1.10]) and inversely associated with ovarian cancer (OR = 0.95 [0.91; 0.99]). The association between PD and ovarian cancer was mostly driven by rs183211 located in an intron of the NSF gene (17q21.31).

CONCLUSIONS

We show evidence in favor of a contribution of pleiotropic genes to the association between PD and specific cancers. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Genetic Evidence for Endolysosomal Dysfunction in Parkinson’s Disease: A Critical Overview

Parkinson’s disease (PD) is the second most common neurodegenerative disorder in the aging population, and no disease-modifying therapy has been approved to date. The pathogenesis of PD has been related to many dysfunctional cellular mechanisms, however, most of its monogenic forms are caused by pathogenic variants in genes involved in endolysosomal function (LRRK2, VPS35, VPS13C, and ATP13A2) and synaptic vesicle trafficking (SNCA, RAB39B, SYNJ1, and DNAJC6). Moreover, an extensive search for PD risk variants revealed strong risk variants in several lysosomal genes (e.g., GBA1, SMPD1, TMEM175, and SCARB2) highlighting the key role of lysosomal dysfunction in PD pathogenesis. Furthermore, large genetic studies revealed that PD status is associated with the overall “lysosomal genetic burden”, namely the cumulative effect of strong and weak risk variants affecting lysosomal genes. In this context, understanding the complex mechanisms of impaired vesicular trafficking and dysfunctional endolysosomes in dopaminergic neurons of PD patients is a fundamental step to identifying precise therapeutic targets and developing effective drugs to modify the neurodegenerative process in PD.

NetRank Recovers Known Cancer Hallmark Genes as Universal Biomarker Signature for Cancer Outcome Prediction

Gene expression can serve as a powerful predictor for disease progression and other phenotypes. Consequently, microarrays, which capture gene expression genome-wide, have been used widely over the past two decades to derive biomarker signatures for tasks such as cancer grading, prognosticating the formation of metastases, survival, and others. Each of these signatures was selected and optimized for a very specific phenotype, tissue type, and experimental set-up. While all of these differences may naturally contribute to very heterogeneous and different biomarker signatures, all cancers share characteristics regardless of particular cell types or tissue as summarized in the hallmarks of cancer. These commonalities could give rise to biomarker signatures, which perform well across different phenotypes, cell and tissue types. Here, we explore this possibility by employing a network-based approach for pan-cancer biomarker discovery. We implement a random surfer model, which integrates interaction, expression, and phenotypic information to rank genes by their suitability for outcome prediction. To evaluate our approach, we assembled 105 high-quality microarray datasets sampled from around 13,000 patients and covering 13 cancer types. We applied our approach (NetRank) to each dataset and aggregated individual signatures into one compact signature of 50 genes. This signature stands out for two reasons. First, in contrast to other signatures of the 105 datasets, it is performant across nearly all cancer types and phenotypes. Second, It is interpretable, as the majority of genes are linked to the hallmarks of cancer in general and proliferation specifically. Many of the identified genes are cancer drivers with a known mutation burden linked to cancer. Overall, our work demonstrates the power of network-based approaches to compose robust, compact, and universal biomarker signatures for cancer outcome prediction.

Monogenic Parkinson’s Disease: Genotype, Phenotype, Pathophysiology, and Genetic Testing

Parkinson’s disease may be caused by a single pathogenic variant (monogenic) in 5–10% of cases, but investigation of these disorders provides valuable pathophysiological insights. In this review, we discuss each genetic form with a focus on genotype, phenotype, pathophysiology, and the geographic and ethnic distribution. Well-established Parkinson’s disease genes include autosomal dominant forms (SNCA, LRRK2, and VPS35) and autosomal recessive forms (PRKN, PINK1 and DJ1). Furthermore, mutations in the GBA gene are a key risk factor for Parkinson’s disease, and there have been major developments for X-linked dystonia parkinsonism. Moreover, atypical or complex parkinsonism may be due to mutations in genes such as ATP13A2, DCTN1, DNAJC6, FBXO7, PLA2G6, and SYNJ1. Furthermore, numerous genes have recently been implicated in Parkinson’s disease, such as CHCHD2, LRP10, TMEM230, UQCRC1, and VPS13C. Additionally, we discuss the role of heterozygous mutations in autosomal recessive genes, the effect of having mutations in two Parkinson’s disease genes, the outcome of deep brain stimulation, and the role of genetic testing. We highlight that monogenic Parkinson’s disease is influenced by ethnicity and geographical differences, reinforcing the need for global efforts to pool large numbers of patients and identify novel candidate genes.

Parkinson's disease and cancer: a systematic review and meta-analysis on the influence of lifestyle habits, genetic variants, and gender

PURPOSE

The relationship between Parkinson's disease (PD) and cancer has been debated. Gender and genetic influences on cancer development in PD is unclear.

METHODS

Using QUOROM guidelines, we conducted a systematic review and meta-analysis on potential clinical and genetic factors influencing the PD and subsequent cancer relationship. English articles published in PubMed, Web of Science, and SCOPUS from 2010 to 30 August 2020 were considered for suitability.

RESULTS

Of 46 studies identified, fourteen satisfied the inclusion criteria and were further analysed. Unadjusted risk ratios (RR) and 95% confidence intervals were computed to determine the PD and cancer relationship. PD patients have decreased subsequent cancer risks (RR = 0.87, 95% CI = 0.81-0.93), reduced risks of colon, rectal, and colorectal cancer (RR = 0.77, 95% CI = 0.63-0.94), lung cancer (RR = 0.62, 95% CI = 0.48-0.80), and increased brain cancer (R = 1.48, 95% CI = 1.02-2.13) and melanoma risk (R = 1.76, 95% CI = 1.23-2.50). Compared to idiopathic PD, LRRK2-G2019S carriers had increased general cancer risks (RR = 1.26, 95% CI = 1.09-1.46), particularly brain (RR = 2.41, 95% CI = 1.06-5.50), breast (RR = 2.57, 95% CI = 1.19-5.58), colon (RR = 1.83, 95% CI = 1.13-2.99), and haematological cancers (RR = 2.05, 95% CI = 1.07-3.92). Female PD patients have decreased general cancer risks compared to male PD patients in this analysis (RR = 0.83, 95% CI = 0.69-0.98).

CONCLUSION

PD patients have reduced risks of colon, rectal, colorectal cancer and lung cancers and increased risks of brain cancer and melanoma. LRRK2-G2019S carriers have increased cancer risks, particularly brain, breast, colon and blood cancers. Female gender was associated with reduced risks. The role of ethnicity, comorbidities, and lifestyle habits on PD patients' subsequent cancer risk should be further investigated.

LRRK2 correlates with macrophage infiltration in pan-cancer

Leucine-rich repeat kinase2 (LRRK2) influences the host immune responses and correlates with the pathogenesis of inflammation, cancer as well as Parkinson' Disease. Herein, we explored the oncogenic role of LRRK2 at pan-cancer level and validated the analysis by single cell RNA-sequencing and in-vitro experiments. As a result, LRRK2 significantly correlated with the survival events. Specifically, LRRK2 increased the risk of Low-Grade Glioma whereas improved the survival probability of patients with Skin Cutaneous Melanoma. Gene set enrichment analysis demonstrated the involvement of LRRK2 in the host immune responses. Within the tumor microenvironment, LRRK2 was positively associated with the recruitment of macrophages. Furthermore, scRNA-seq and co-culture experiments demonstrated that LRRK2 deficiency impaired macrophage functions, and influenced the neoplastic progression in a cancer type-specific manner. Therefore, the present study provided a therapeutic strategy for LGG based on the interference with LRRK2 expression and activity to prevent macrophage recruitment and promote tumor eradication.

Association of AXIN1 With Parkinson's Disease in a Taiwanese Population

Objective

A meta-analysis of locus-based genome-wide association studies recently identified a relationship between AXIN1 and Parkinson’s disease (PD). Few studies of Asian populations, however, have reported such a genetic association. The influences of rs13337493, rs758033, and rs2361988, three PD-associated genetic variants of AXIN1, were investigated in the present study because AXIN1 is related to Wnt/β-catenin signaling.

Methods

A total of 2,418 individuals were enrolled in our Taiwanese cohort for analysis of the genotypic and allelic frequency. Polymerase chain reaction–restriction fragment length polymorphism analysis was employed for rs13337493 genotyping, and the Agena MassARRAY platform (Agena Bioscience, San Diego, CA, USA) was used for rs758033 and rs2361988 genotyping in 672 patients with PD and 392 controls. Taiwan Biobank data of another 1,354 healthy controls were subjected to whole-genome sequencing performed using Illumina platforms at approximately 30× average depth.

Results

Our results revealed that rs758033 {odds ratios [OR] (95% confidence interval [CI]) = 0.267 [0.064, 0.795], p = 0.014} was associated with the risk of PD, and there was a trend toward a protective effect of rs2361988 (OR [95% CI] = 0.296 [0.071, 0.884], p = 0.026) under the recessive model. The TT genotype of rs758033 (OR [95% CI] = 0.271 [0.065, 0.805], p = 0.015) and the CC genotype of rs2361988 (OR [95% CI] = 0.305 [0.073, 0.913], p = 0.031) were less common in the PD group than in the non-PD group.

Conclusion

Our findings indicate that the rs758033 and rs2361988 polymorphisms of AXIN1 may affect the risk of PD in the Taiwanese population.

Cancer in Parkinson’s Disease, a Review of Literature

Background/Aim: The present study aimed to assess the conclusions of literature articles on the matter of cancer in Parkinson’s disease.

Patients and Methods: Studies and articles that contained information on epidemiology, pathophysiological, clinical as well as associations and correlations on the topic of Parkinson’s disease and cancer were incorporated in the research too.

Results: The prevalent part of the investigations and studies on the matter of Parkinson’s disease patients’ risk of cancer revealed a decreased lifetime risk in comparisson with non-PD subjects. In the literature, the most prevalent types of cancer among Parkinson’s disease patients were melanoma and other subtypes skin cancer and also, breast cancer.

Conclusion: Epigenetic factors, gene–environment interactions, and problematic events can have an impact in the occurance and progression of Parkinson’s disease. Further, the mentioned factors can also determine the developing of cancer. Therefore, a complex and interesting relation between the two diseases is further to be discovered.

LRRK2 is required for CD38-mediated NAADP-Ca2+ signaling and the downstream activation of TFEB (transcription factor EB) in immune cells

CD38 is a cell surface receptor capable of generating calcium-mobilizing second messengers. It has been implicated in host defense and cancer biology, but signaling mechanisms downstream of CD38 remain unclear. Mutations in LRRK2 (leucine-rich repeat kinase 2) are the most common genetic cause of Parkinson disease; it is also a risk factor for Crohn disease, leprosy, and certain types of cancers. The pathogenesis of these diseases involves inflammation and macroautophagy/autophagy, processes both CD38 and LRRK2 are implicated in. Here, we mechanistically and functionally link CD38 and LRRK2 as upstream activators of TFEB (transcription factor EB), a host defense transcription factor and the master transcriptional regulator of the autophagy/lysosome machinery. In B-lymphocytes and macrophages, we show that CD38 and LRRK2 exist in a complex on the plasma membrane. Ligation of CD38 with the monoclonal antibody clone 90 results in internalization of the CD38-LRRK2 complex and its targeting to the endolysosomal system. This generates an NAADP-dependent calcium signal, which requires LRRK2 kinase activity, and results in the downstream activation of TFEB. lrrk2 KO macrophages accordingly have TFEB activation defects following CD38 or LPS stimulation and fail to switch to glycolytic metabolism after LPS treatment. In overexpression models, the pathogenic LRRK2^G2019S mutant promotes hyperactivation of TFEB even in the absence of CD38, both by stabilizing TFEB and promoting its nuclear translocation via aberrant calcium signaling. In sum, we have identified a physiological CD38-LRRK2-TFEB signaling axis in immune cells. The common pathogenic mutant, LRRK2^G2019S, appears to hijack this pathway.

Abbreviations:ADPR: ADP-ribose; AMPK: AMP-activated protein kinase; BMDM: bone marrow-derived macrophage; cADPR: cyclic-ADP-ribose; COR: C-terminal of ROC; CTSD: cathepsin D; ECAR: extracellular acidification rate; EDTA: ethylenediaminetetraacetic acid; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; GPN: Gly-Phe β-naphthylamide; GSK3B/GSK3β: glycogen synthase kinase 3 beta; GTP: guanosine triphosphate; KD: knockdown; LAMP1: lysosomal-associated membrane protein 1; LRR: leucine rich repeat; LRRK2: leucine rich repeat kinase 2; mAb: monoclonal antibody; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK/ERK: mitogen-activated protein kinase; MCOLN1: mucolipin 1; MFI: mean fluorescence intensity; mRNA: messenger RNA; MTOR: mechanistic target of rapamycin kinase; NAADP: nicotinic acid adenine dinucleotide phosphate; NAD: nicotinamide adenine dinucleotide; NADP: nicotinamide adenine dinucleotide phosphate; PD: Parkinson disease; PPP3CB: protein phosphatase 3, catalytic subunit, beta isoform; q-RT-PCR: quantitative reverse transcription polymerase chain reaction; ROC: Ras of complex; siRNA: small interfering RNA; SQSTM1/p62: sequestome 1; TFEB: transcription factor EB; TPCN: two pore channel; TRPM2: transient receptor potential cation channel, subfamily M, member 2; ZKSCAN3: zinc finger with KRAB and SCAN domains 3

SNPs within microRNA binding sites and the prognosis of breast cancer

Single nucleotide polymorphisms (SNPs) within microRNA binding sites can affect the binding of microRNA to mRNA and regulate gene expression, thereby contributing to cancer prognosis. Here we performed a two-stage study of 2647 breast cancer patients to explore the association between SNPs within microRNA binding sites and breast cancer prognosis. In stage I, we genotyped 192 SNPs within microRNA binding sites using the Illumina Goldengate platform. In stage II, we validated SNPs associated with breast cancer prognosis in another dataset using the TaqMan platform. We identified 8 SNPs significantly associated with breast cancer prognosis in stage I (P<0.05), and only rs10878441 was statistically significant in stage II (AA vs CC, HR=2.21, 95% CI: 1.11-4.42, P=0.024). We combined the data from stage I and stage II, and found that, compared with rs10878441 AA genotype, CC genotype was associated with poor survival of breast cancer (HR=2.19, 95% CI: 1.30-3.70, P=0.003). Stratified analyses demonstrated that rs10878441 was related to breast cancer prognosis in grade II and lymph node-negative patients (P<0.05). The Leucine-rich repeat kinase 2 (LRRK2) rs10878441 CC genotype is associated with poor prognosis of breast cancer in a Chinese population and may be used as a potential prognostic biomarker for breast cancer.

• The LRRK2 rs10878441 CC genotype is associated with poor prognosis of breast cancer in a Chinese population.

• Stratified analyses demonstrated that rs10878441 was related to breast cancer prognosis in grade II patients and lymph node-negative patients.

Inflammatory Diseases Among Norwegian LRRK2 Mutation Carriers. A 15-Years Follow-Up of a Cohort

The first families with LRRK2 related Parkinson’s disease (PD) were presented around 15 years ago and numerous papers have described the characteristics of the LRRK2 phenotype. The prevalence of autosomal dominant PD varies around the world mainly depending on local founder effects. The highest prevalence of LRRK2 G2019S PD in Norway is located to the central part of the country and most families could be traced back to common ancestors. The typical Norwegian LRRK2 phenotype is not different from classical PD and similar to that seen in most other LRRK2 families. The discovery of LRRK2 PD has allowed us to follow-up multi-incident families and to study their phenotype longitudinally. In the Norwegian LRRK2 families there has been a significantly higher incidence of inflammatory diseases like multiple sclerosis and rheumatoid arthritis that seen in other PD populations. Recent studies in LRRK2 mechanisms have indicated that this protein may be crucial in initiating disease processes. In this short survey of 100 Norwegian mutation carriers followed through more than 15 years are presented. The prevalence of inflammatory diseases among these cases is highlighted. The role of LRRK2 in the conversion process from carrier status to PD phenotype is still unknown and disease generating mechanisms important for initiating LRRK2 PD are still to be identified.

A Report of Tamoxifen and Parkinson's Disease in a US Population and a Review of the Literature

BACKGROUND

Tamoxifen, a selective estrogen receptor modulator, has been shown to variably affect Parkinson's disease (PD) risk.

OBJECTIVE

The aim of this study was to review epidemiological literature and evaluate the rate of PD in women with breast cancer with tamoxifen exposure in a US population.

METHODS

A literature search was conducted to identify relevant studies. We performed a retrospective cohort analysis using the Nurses' Health Study Version One to report descriptive statistics.

RESULTS

Most studies suggest there may be a time-dependent effect of tamoxifen on PD risk, with the risk increasing with time from exposure. However, rates of PD in persons exposed to tamoxifen overall appear to be low. In our cohort, PD was evident in 6.2 per 1,000 of those with tamoxifen use and 3.6 per 1,000 of those without tamoxifen use. Time from breast cancer to PD diagnosis was 9.7 years among women with tamoxifen exposure and 11.7 among women without.

CONCLUSIONS

Tamoxifen may be associated with an increased risk for PD. Further research is needed to elucidate the role of estrogen and selective estrogen antagonism in PD. © 2021 International Parkinson and Movement Disorder Society.

Inhibition of the Activity of Cyclophilin A Impedes Prolactin Receptor-Mediated Signaling, Mammary Tumorigenesis, and Metastases

Prolactin (PRL) and its receptor (PRLr) play important roles in the pathogenesis of breast cancer. Cyclophilin A (CypA) is a cis-trans peptidyl-prolyl isomerase (PPI) that is constitutively associated with the PRLr and facilitates the activation of the tyrosine kinase Jak2. Treatment with the non-immunosuppressive prolyl isomerase inhibitor NIM811 or CypA short hairpin RNA inhibited PRL-stimulated signaling, breast cancer cell growth, and migration. Transcriptomic analysis revealed that NIM811 inhibited two-thirds of the top 50 PRL-induced genes and a reduction in gene pathways associated with cancer cell signaling. In vivo treatment of NIM811 in a TNBC xenograft lessened primary tumor growth and induced central tumor necrosis. Deletion of CypA in the MMTV-PyMT mouse model demonstrated inhibition of tumorigenesis with significant reduction in lung and lymph node metastasis. The regulation of PRLr/Jak2-mediated biology by NIM811 demonstrates that a non-immunosuppressive prolyl isomerase inhibitor can function as a potential breast cancer therapeutic.

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CypA inhibition or knockdown blocks breast cancer cell signaling, growth, and migration

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NIM811 inhibited PRL-induced genes and gene pathways relevant to cancer signaling

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Deletion of CypA has shown reduction in tumorigenesis and metastasis in mice

Somatic Mutations in LRRK2 Identify a Subset of Invasive Mammary Carcinomas Associated with High Mutation Burden

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of familial Parkinson disease. Although LRRK2-related Parkinson disease patients have a heightened risk of certain nonskin cancers, including breast cancer, it is unknown whether LRRK2 somatic mutations occur and are associated with breast cancer. The objective of this study was to evaluate the occurrence of LRRK2 somatic mutations in breast cancer and the clinicopathologic features associated with LRRK2-mutated tumors. Using The Cancer Genome Atlas Breast Cancer Project, somatic LRRK2 DNA sequence information was obtained for 93 cases, of which 17 cases (18%) with 18 mutations were identified. LRRK2-mutated mammary carcinomas are enriched with stop-gain, truncating mutations predicted to result in loss of function; missense mutations frequently targeted the GTPase and kinase domains. Tumors displayed predominantly high-grade morphology with abundant granular eosinophilic cytoplasm, resembling mitochondria-rich apocrine-like carcinomas. Exploration of the genomic landscape of LRRK2-mutated carcinomas yielded frequent TP53 deactivation and a remarkably high tumor mutation burden. More important, breast cancers with LRRK2 mutations are associated with reduced patient survival compared with The Cancer Genome Atlas Breast Cancer Project cohort. These findings, for the first time, show that somatic LRRK2 mutations occur frequently in breast cancer, and the high mutation burden seen in this subset of tumors suggests that LRRK2 mutations may herald benefit from immune checkpoint inhibition.

Comprehensive Genomic Analysis Reveals the Prognostic Role of LRRK2 Copy-Number Variations in Human Malignancies

Genetic alterations of leucine-rich repeat kinase 2 (LRRK2), one of the most important contributors to familial Parkinson’s disease (PD), have been hypothesized to play a role in cancer development due to demographical and preclinical data. Here, we sought to define the prevalence and prognostic significance of LRRK2 somatic mutations across all types of human malignancies by querying the publicly available online genomic database cBioPortal. Ninety-six different studies with 14,041 cases were included in the analysis, and 761/14,041 (5.4%) showed genetic alterations in LRRK2. Among these, 585 (76.9%) were point mutations, indels or fusions, 168 (22.1%) were copy number variations (CNVs), and 8 (1.0%) showed both types of alterations. One case showed the somatic mutation R1441C. A significant difference in terms of overall survival (OS) was noted between cases harboring somatic LRRK2 whole deletions, amplifications, and CNV-unaltered cases (median OS: 20.09, 57.40, and 106.57 months, respectively; p = 0.0008). These results suggest that both LRRK2 amplifications and whole gene deletions could play a role in cancer development, paving the way for future research in terms of potential treatment with LRRK2 small molecule inhibitors for LRRK2-amplified cases.

LRRK2 Is Associated with Recurrence-Free Survival in Intrahepatic Cholangiocarcinoma and Downregulation of LRRK2 Suppresses Tumor Progress In Vitro

BACKGROUND

The leucine-rich repeat kinase 2 (LRRK2) gene was confirmed to be associated with a variety of diseases, while the physiological function of LRRK2 remains poorly understood. Intrahepatic cholangiocarcinoma (ICC) has over the last 10 years become the focus of increasing concern largely. Despite recent progress in the standard of care and management options for ICC, the prognosis for this devastating cancer remains dismal.

METHODS

A total of 57 consecutive ICC patients who underwent curative hepatectomy in our institution were included in our study. We conduct a retrospective study to evaluate the prognostic value of LRRK2 in ICC after resection. The mechanism of LRRK2 in ICC development was also investigated in vitro.

RESULTS

All patients were divided into two groups according to the content of LRRK2 in the tissue microarray blocks via immunohistochemistry: low-LRRK2 group (n = 33) and high-LRRK2 group (n = 24). The recurrence-free survival rate of high-LRRK2 group was significantly poorer than that of low-LRRK2 group (P = 0.010). Multivariate analysis showed high-LRRK2 was the prognostic factor for recurrence-free survival after hepatectomy. We demonstrated that downregulation of LRRK2 depressed the proliferation and metastasis of ICC cells in vitro.

CONCLUSION

We provide evidence that LRRK2 was an independent prognostic factor for ICC in humans by participating in the proliferation and metastasis of ICC cells.

Cancer outcomes among Parkinson's disease patients with leucine rich repeat kinase 2 mutations, idiopathic Parkinson's disease patients, and nonaffected controls

BACKGROUND

Increased cancer risk has been reported in Parkinson's disease (PD) patients carrying the leucine rich repeat kinase 2 (LRRK2) G2019S mutation (LRRK2-PD) in comparison with idiopathic PD (IPD). It is unclear whether the elevated risk would be maintained when compared with unaffected controls.

METHODS

Cancer outcomes were compared among 257 LRRK2-PD patients, 712 IPD patients, and 218 controls recruited from 7 LRRK2 consortium centers using mixed-effects logistic regression. Data were then pooled with a previous study to examine cancer risk between 401 LRRK2-PD and 1946 IPD patients.

RESULTS

Although cancer prevalence was similar among LRRK2-PD patients (32.3%), IPD patients (27.5%), and controls (27.5%; P = 0.33), LRRK2-PD had increased risks of leukemia (odds ratio [OR] = 4.55; 95% confidence interval [CI], 1.46-10.61) and skin cancer (OR = 1.61; 95% CI, 1.09-2.37). In the pooled analysis, LRRK2-PD patients had also elevated risks of leukemia (OR = 9.84; 95% CI, 2.15-44.94) and colon cancer (OR = 2.34; 95% CI, 1.15-4.74) when compared with IPD patients.

CONCLUSIONS

The increased risks of leukemia as well as skin and colon cancers among LRRK2-PD patients suggest that LRRK2 mutations heighten risks of certain cancers. © 2019 International Parkinson and Movement Disorder Society.

Signals Getting Crossed in the Entanglement of Redox and Phosphorylation Pathways: Phosphorylation of Peroxiredoxin Proteins Sparks Cell Signaling

Reactive oxygen and nitrogen species have cell signaling properties and are involved in a multitude of processes beyond redox homeostasis. The peroxiredoxin (Prdx) proteins are highly sensitive intracellular peroxidases that can coordinate cell signaling via direct reactive species scavenging or by acting as a redox sensor that enables control of binding partner activity. Oxidation of the peroxidatic cysteine residue of Prdx proteins are the classical post-translational modification that has been recognized to modulate downstream signaling cascades, but increasing evidence supports that dynamic changes to phosphorylation of Prdx proteins is also an important determinant in redox signaling. Phosphorylation of Prdx proteins affects three-dimensional structure and function to coordinate cell proliferation, wound healing, cell fate and lipid signaling. The advent of large proteomic datasets has shown that there are many opportunities to understand further how phosphorylation of Prdx proteins fit into intracellular signaling cascades in normal or malignant cells and that more research is necessary. This review summarizes the Prdx family of proteins and details how post-translational modification by kinases and phosphatases controls intracellular signaling.