The associations between Parkinson's disease and cancer: the plot thickens

Comprehensive Analysis and Experimental Validation of the Parkinson's Disease Lysosomal Gene ACP2 and Pan-cancer

The pivotal role of lysosomal function in preserving neuronal homeostasis is recognized, with its dysfunction being implicated in neurodegenerative processes, notably in Parkinson's disease (PD). Yet, the molecular underpinnings of lysosome-related genes (LRGs) in the context of PD remain partially elucidated. We collected RNA-seq data from the brain substantia nigra of 30 PD patients and 20 normal subjects from the GEO database. We obtained molecular classification clusters from the screened lysosomal expression patterns. The lysosome-related diagnostic model of Parkinson's disease was constructed by XGBoost and Random Forest. And we validated the expression patterns of signature LRGs in the diagnostic model by constructing a PD rat model. Finally, the linkage between PD and cancer through signature genes was explored. The expression patterns of the 33 LRGs screened can be divided into two groups of PD samples, enabling exploration of the variance in biological processes and immune elements. Cluster A had a higher disease severity. Subsequently, critical genes were sieved through the application of machine learning methodologies culminating in the identification of two intersecting feature genes (ACP2 and LRP2). A PD risk prediction model was constructed grounded on these signature genes. The model's validity was assessed through nomogram evaluation, which demonstrated robust confidence validity. Then we analyzed the correlation analysis, immune in-filtration, biological function, and rat expression validation of the two genes with common pathogenic genes in Parkinson's disease, indicating that these two genes play an important role in the pathogenesis of PD. We then selected ACP2, which had a significant immune infiltration correlation, as the entry gene for the pan-cancer analysis. The pan-cancer analysis revealed that ACP2 has profound associations with prognostic indicators, immune infiltration, and tumor-related regulatory processes across various neoplasms, suggesting its potential as a therapeutic target in a range of human diseases, including PD and cancers. Our study comprehensively analyzed the molecular grouping of LRGs expression patterns in Parkinson's disease, and the disease progression was more severe in cluster A. And the PD diagnosis model related to LRGs is constructed. Finally, ACP2 is a potential target for the relationship between Parkinson's disease and tumor.

Causal association between Parkinson's disease and cancer: a bidirectional Mendelian randomization study

Background

Previous observational research has indicated a correlation between Parkinson's disease (PD) and multiple cancers; but the causality remains unclear. Thus, we utilized Mendelian randomization (MR) analysis to explore the potential causal link between PD and various cancers.

Methods

We conducted a bidirectional two-sample Mendelian randomization (TSMR) of genetic variants associated with PD and 14 types of cancers. Summary statistics on PD and 14 types of cancers were obtained from the International Parkinson's Disease Genomics Consortium and the study by Sakaue et al. The primary method employed was inverse variance weighted (IVW), complemented by multiple sensitivity analyses to evaluate heterogeneity and pleiotropy. The false discovery rate (FDR) was employed to control the false positive rate of multiple hypothesis testing.

Results

Following rigorous sensitivity analyses and corrections, our findings revealed suggestive associations between PD and certain cancers. We observed that PD decreases the risk of gastric cancer and colorectal cancer (OR = 0.936, 95% CI = 0.881-0.995, p = 0.034, P FDR = 0.239; OR = 0.955, 95% CI = 0.912-0.999, p = 0.046, P FDR = 0.215), while increasing the risk of breast cancer (OR = 1.043, 95% CI = 1.004-1.084, p = 0.029, P FDR = 0.402). Notably, we found no evidence supporting a reverse causal relationship. Additionally, in the reverse pathway, skin cancer demonstrated a suggestive causal relationship with PD (OR = 0.913, 95% CI = 0.857-0.973, p = 0.005, P FDR = 0.066).

Conclusion

Our MR analysis provides evidence supporting unidirectional suggestive causal relationships between PD and certain cancers. These findings enrich our comprehension of the intricate interplay between PD and cancer, warranting further investigation into the underlying biological mechanisms.

Suppression of Glioblastoma Stem Cell Potency and Tumor Growth via LRRK2 Inhibition

Leucine-rich repeat kinase 2 (LRRK2), a large GTP-regulated serine/threonine kinase, is well-known for its mutations causing late-onset Parkinson's disease. However, the role of LRRK2 in glioblastoma (GBM) carcinogenesis has not yet been fully elucidated. Here, we discovered that LRRK2 was overexpressed in 40% of GBM patients, according to tissue microarray analysis, and high LRRK2 expression correlated with poor prognosis in GBM patients. LRRK2 and stemness factors were highly expressed in various patient-derived GBM stem cells, which are responsible for GBM initiation. Canonical serum-induced differentiation decreased the expression of both LRRK2 and stemness factors. Given that LRRK2 is a key regulator of glioma stem cell (GSC) stemness, we developed DNK72, a novel LRRK2 kinase inhibitor that penetrates the blood-brain barrier. DNK72 binds to the phosphorylation sites of active LRRK2 and dramatically reduced cell proliferation and stemness factors expression in in vitro studies. Orthotopic patient-derived xenograft mouse models demonstrated that LRRK2 inhibition with DNK72 effectively reduced tumor growth and increased survival time. We propose that LRRK2 plays a significant role in regulating the stemness of GSCs and that suppression of LRRK2 kinase activity leads to reduced GBM malignancy and proliferation. In the near future, targeting LRRK2 in patients with high LRRK2-expressing GBM could offer a superior therapeutic strategy and potentially replace current clinical treatment methods.

Head and Neck Cancer: A Potential Risk Factor for Parkinson's Disease?

Head and neck cancers (HNC) are frequently associated with neurodegeneration. However, the association between HNC and Parkinson's disease (PD) remains unclear. This study aimed to clarify the relationship between HNC and subsequent PD. This retrospective study used data from a nationally representative cohort. Patients with HNC were identified based on the presence of corresponding diagnostic codes. Participants without cancer were selected using 4:1 propensity score matching based on sociodemographic factors and year of enrollment; 2296 individuals without HNC and 574 individuals with HNC were included in the study. Hazard ratios (HR) for the incidence of PD in patients with HNC were calculated using 95% confidence intervals (CI). The incidence of PD was 4.17 and 2.18 per 1000 person-years in the HNC and control groups, respectively (adjusted HR = 1.89, 95% CI = 1.08-3.33). The HNC group also showed an increased risk of subsequent PD development. The risk of PD was higher in middle-aged (55-69 years) patients with HNC and oral cavity cancer. Our findings suggest that middle-aged patients with HNC have an increased incidence of PD, specifically those with oral cavity cancer. Therefore, our findings provide new insights into the development of PD in patients with HNC.

Association between Parkinson's Disease and Cancer: New Findings and Possible Mediators

Epidemiological evidence points to an inverse association between Parkinson's disease (PD) and almost all cancers except melanoma, for which this association is positive. The results of multiple studies have demonstrated that patients with PD are at reduced risk for the majority of neoplasms. Several potential biological explanations exist for the inverse relationship between cancer and PD. Recent results identified several PD-associated proteins and factors mediating cancer development and cancer-associated factors affecting PD. Accumulating data point to the role of genetic traits, members of the synuclein family, neurotrophic factors, the ubiquitin-proteasome system, circulating melatonin, and transcription factors as mediators. Here, we present recent data about shared pathogenetic factors and mediators that might be involved in the association between these two diseases. We discuss how these factors, individually or in combination, may be involved in pathology, serve as links between PD and cancer, and affect the prevalence of these disorders. Identification of these factors and investigation of their mechanisms of action would lead to the discovery of new targets for the treatment of both diseases.

Targeted upregulation of dMyc restricts JNK-mediated degeneration of dopaminergic neurons in the paraquat-induced Parkinson's disease model of Drosophila

Parkinson's disease is the second most common neurodegenerative disease characterized by the loss of dopaminergic neurons in the brain. Parkinson's disease has both familial and sporadic cases of origin governed differentially by genetic and/or environmental factors. Different epidemiological studies have proposed an association between the pathogenesis of cancer and Parkinson's disease; however, a precise correlation between these two illnesses could not be established yet. In this study, we examined the disease-modifying property of dmyc (a Drosophila homolog of human cmyc proto-oncogene) in the paraquat-induced sporadic Parkinson's disease model of Drosophila. We report for the first time that targeted upregulation of dMyc significantly restricts paraquat-mediated neurotoxicity. We observed that paraquat feeding reduces the cellular level of dMyc. We further noted that targeted upregulation of dMyc in paraquat-exposed flies mitigates degeneration of dopaminergic neurons by reinstating the aberrantly activated JNK pathway, and this in turn improves the motor performance and survival rate of the flies. Our study provides the first evidence that improved cellular level of dMyc could efficiently minimize the neurotoxic effects of paraquat, which could be beneficial in designing novel therapeutic strategies against Parkinson's disease.

Risk of Parkinson's disease-related death in cancer survivors: A population-based study in Japan

BACKGROUND

The risk of Parkinson's disease (PD)-related death in patients with cancer largely unexplored.

METHODS

We analyzed data from the Neoplasms ANd other causes of DEath (NANDE) study, which investigates the causes of death in patients with cancer in Japan. Standardized mortality ratios (SMRs) were calculated to compare the risk of PD-related deaths in patients with cancer to that of the general population. Poisson regression models were employed to estimate the relative risk of PD-related death in the subgroups.

RESULTS

The cohort included 548,485 patients with cancer, yielding 2,047,398 person-years at risk from 1995 to 2013. During the study period, 242,250 patients died and 145 deaths were attributable to PD. The SMR for PD-related death was 2.34 (95% confidence interval [CI]: 1.99-2.75). Patients who were diagnosed with cancer before 70 years of age had a high SMR (>5) for PD-related deaths. The SMR of patients with mouth-to-stomach cancers (lip, oral cavity, pharynx, esophagus, and stomach cancers) was 3.72 (95% CI: 2.84-4.86), while that of those with other cancers was 1.93 (95% CI: 1.57-2.37). The multivariate Poisson regression model revealed that patients with mouth-to-stomach cancers were more likely to die of PD than those without (relative risk 2.07, 95 % CI; 1.46-2.93).

CONCLUSIONS

Patients with cancer are at a high risk of PD-related death; particularly, mouth-to-stomach cancers and potentially obstructing medication for PD are attributable to a high mortality risk. Careful management, including adequate PD treatment, would benefit cancer survivors with PD and reduce the risk of PD-related death.

Glutamate Receptors and C-ABL Inhibitors: A New Therapeutic Approach for Parkinson's Disease

Parkinson's disease (PD) is the second-most prevalent central nervous system (CNS) neurodegenerative condition. Over the past few decades, suppression of BCR-Abelson tyrosine kinase (c-Abl), which serves as a marker of -synuclein aggregation and oxidative stress, has shown promise as a potential therapy target in PD. c-Abl inhibition has the potential to provide neuroprotection against PD, as shown by experimental results and the first-in-human trial, which supports the strategy in bigger clinical trials. Furthermore, glutamate receptors have also been proposed as potential therapeutic targets for the treatment of PD since they facilitate and regulate synaptic neurotransmission throughout the basal ganglia motor system. It has been noticed that pharmacological manipulation of the receptors can change normal as well as abnormal neurotransmission in the Parkinsonian brain. The review study contributes to a comprehensive understanding of the approach toward the role of c-Abl and glutamate receptors in Parkinson's disease by highlighting the significance and urgent necessity to investigate new pharmacotherapeutic targets. The article covers an extensive insight into the concept of targeting, pathophysiology, and c-Abl interaction with α-synuclein, parkin, and cyclin-dependent kinase 5 (Cdk5). Furthermore, the concepts of Nmethyl- D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPA) receptor, and glutamate receptors are discussed briefly. Conclusion: This review article focuses on in-depth literature findings supported by an evidence-based discussion on pre-clinical trials and clinical trials related to c-Abl and glutamate receptors that act as potential therapeutic targets for PD.

Longitudinal study of the inverse relationship between Parkinson's disease and cancer in Korea

Despite growing epidemiological evidence, the relationship between Parkinson's disease (PD) and cancer has not been conclusively demonstrated, and related studies are scarce in the Asian population. We aimed to determine the association between PD and subsequent development of various cancers from longitudinal data of a representative sample of Korean adults aged ≥40 years. We retrospectively identified 8381 patients diagnosed with PD from 2002 to 2019 using claims data among 514,866 people of random samples from the Korean National Health Insurance database. We sampled 33,524 age-, sex-, income-, and residential area-matched participants without PD from the same database. The longitudinal associations between PD and overall cancer, as well as 10 common types of cancer, were estimated using multivariable Cox proportional-hazards regression analysis. The adjusted hazard ratio (aHR) of all cancer types was 0.63 (95% confidence interval = 0.57-0.69) in patients with PD compared with matched controls. The aHRs of gastric, thyroid, colorectal, lung, hepatic, and pancreatic cancer and hematological malignancy were 0.69 (0.56-0.85), 0.60 (0.39-0.93), 0.56 (0.44-0.70), 0.71 (0.58-0.84), 0.64 (0.48-0.86), 0.37 (0.23-0.60), and 0.56 (0.36-0.87), respectively. The associations of bladder, gallbladder and biliary duct, and kidney cancer with PD were not statistically significant. Our findings show inverse associations between overall cancer and most cancer types in patients with PD. These inverse associations and their pathogeneses merit further investigation.

The Sherpa hypothesis: Phenotype-Preserving Disordered Proteins stabilize the phenotypes of neurons and oligodendrocytes

Intrinsically disordered proteins (IDPs), which can interact with many partner proteins, are central to many physiological functions and to various pathologies that include neurodegeneration. Here, we introduce the Sherpa hypothesis, according to which a subset of stable IDPs that we term Phenotype-Preserving Disordered Proteins (PPDP) play a central role in protecting cell phenotypes from perturbations. To illustrate and test this hypothesis, we computer-simulate some salient features of how cells evolve and differentiate in the presence of either a single PPDP or two incompatible PPDPs. We relate this virtual experiment to the pathological interactions between two PPDPs, α-synuclein and Tubulin Polymerization Promoting Protein/p25, in neurodegenerative disorders. Finally, we discuss the implications of the Sherpa hypothesis for aptamer-based therapies of such disorders.

Ovarian Cancer and Parkinson's Disease: A Bidirectional Mendelian Randomization Study

(1) Background: Ovarian cancer (OC) and Parkinson's disease (PD) represent a huge public health burden. The relationship of these two diseases is suggested in the literature while not fully understood. To better understand this relationship, we conducted a bidirectional Mendelian ran-domization analysis using genetic markers as a proxy. (2) Methods: Utilizing single nucleotide polymorphisms associated with PD risk, we assessed the association between genetically predicted PD and OC risk, overall and by histotypes, using summary statistics from previously conducted genome-wide association studies of OC within the Ovarian Cancer Association Consortium. Similarly, we assessed the association between genetically predicted OC and PD risk. The inverse variance weighted method was used as the main method to estimate odds ratios (OR) and 95% confidence intervals (CI) for the associations of interest. (3) Results: There was no significant association between genetically predicted PD and OC risk: OR = 0.95 (95% CI: 0.88-1.03), or between genetically predicted OC and PD risk: OR = 0.80 (95% CI: 0.61-1.06). On the other hand, when examined by histotypes, a suggestive inverse association was observed between genetically predicted high grade serous OC and PD risk: OR = 0.91 (95% CI: 0.84-0.99). (4) Conclusions: Overall, our study did not observe a strong genetic association between PD and OC, but the observed potential association between high grade serous OC and reduced PD risk warrants further investigation.

Neurotransmitter signaling: a new frontier in colorectal cancer biology and treatment

The brain-gut axis, a bidirectional network between the central and enteric nervous system, plays a critical role in modulating the gastrointestinal tract function and homeostasis. Recently, increasing evidence suggests that neuronal signaling molecules can promote gastrointestinal cancers, however, the mechanisms remain unclear. Aberrant expression of neurotransmitter signaling genes in colorectal cancer supports the role of neurotransmitters to stimulate tumor growth and metastatic spread by promoting cell proliferation, migration, invasion, and angiogenesis. In addition, neurotransmitters can interact with immune and endothelial cells in the tumor microenvironment to promote inflammation and tumor progression. As such, pharmacological targeting of neurotransmitter signaling represent a promising novel anticancer approach. Here, we present an overview of the current evidence supporting the role of neurotransmitters in colorectal cancer biology and treatment.

Parkinson’s Disease Etiology: Insights and Associations with Phosphate Toxicity

The present paper investigated the association of Parkinson’s disease etiology with phosphate toxicity, a pathophysiological condition in which dysregulated phosphate metabolism causes excessive inorganic phosphate sequestration in body tissue that damages organ systems. Excessive phosphate is proposed to reduce Complex I function of the mitochondrial electron transport chain in Parkinson’s disease and is linked to opening of the mitochondrial permeability transition pore, resulting in increased reactive oxygen species, inflammation, DNA damage, mitochondrial membrane depolarization, and ATP depletion causing cell death. Parkinson’s disease is associated with α-synuclein and Lewy body dementia, a secondary tauopathy related to hyperphosphorylation of tau protein, and tauopathy is among several pathophysiological pathways shared between Parkinson’s disease and diabetes. Excessive phosphate is also associated with ectopic calcification, bone mineral disorders, and low levels of serum vitamin D in patients with Parkinson’s disease. Sarcopenia and cancer in Parkinson’s disease patients are also associated with phosphate toxicity. Additionally, Parkinson’s disease benefits are related to low dietary phosphate intake. More studies are needed to investigate the potential mediating role of phosphate toxicity in the etiology of Parkinson’s disease.

Doxorubicin induced aggregation of α-synuclein: Insights into the mechanism of drug induced Parkinsonism

The aggregation of α-synuclein is a prominent feature of Parkinson's disease. It is induced by factors such as genetic mutations and presence of metal salts leading to Parkinson's like symptoms. Existing case studies show that patients undergoing cancer chemotherapeutics are also prone to developing Parkinson's like symptoms. However, the underlying cause behind onset of these symptoms is not understood. It is not clear whether the administration of chemotherapeutic drugs alter the structural stability of α-synuclein. In the present study, we address this question by looking into the effect of chemotherapeutic drug namely doxorubicin on the α-synuclein stability. Using complementary spectroscopic, molecular docking and imaging techniques, we observe that doxorubicin interacted with central aggregation prone region of α-synuclein and induces destabilization leading to aggregation. We also show that the combination of doxorubicin and L-DOPA drugs impedes the α-synuclein aggregation. This may explain the reason behind the effectiveness of using L-DOPA against Parkinson's like symptoms.

Comprehensive Profiling of Blood Coagulation and Fibrinolysis Marker Reveals Elevated Plasmin-Antiplasmin Complexes in Parkinson's Disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disease. Accumulating evidence demonstrates that alpha-synuclein (α-Syn), an apparently predominant neuronal protein, is a major contributor to PD pathology. As α-Syn is also highly abundant in blood, particularly in red blood cells (RBCs) and platelets, this in turn raises the question on the function of presumably dysfunctional α-Syn in "peripheral" cells and its putative effect on the other enclosed constituents. Herein, we detected the internal variance in erythrocytes of PD patients by Raman spectroscopy, but no measurable amount of erythrocytic behavioural change (eryptosis) or any haemoglobin variation was noticed. An elevated level of plasmin-antiplasmin complexes (PAP) was observed in the plasma of PD patients, indicating activation of the fibrinolytic system, but platelet activation after thrombin stimulation was not altered. Sex-specific patterns were noticed for blood coagulation factor XIII and factor XII activity in PD patients. Additionally, the alterations in homocysteine levels which have often been observed in PD patients were found to be independent from L-DOPA usage and PAP levels. Furthermore, a selective gene expression analysis identified subsets of genes related to different blood-associated compartments (RBCs, platelets, coagulation-fibrinolysis) also involved in PD-related pathways.

Parkinson's disease and cancer: a systematic review and meta-analysis of over 17 million participants

OBJECTIVE

To systematically review and qualitatively evaluate epidemiological evidence on associations between Parkinson's disease (PD) and cancer via meta-analysis.

DATA SOURCES

MEDLINE via PubMed, Web of Science and EMBASE, until March 2021.

STUDY SELECTION

Included were publications that (1) were original epidemiological studies on PD and cancer; (2) reported risk estimates; (3) were in English. Exclusion criteria included: (1) review/comments; (2) biological studies; (3) case report/autopsy studies; (4) irrelevant exposure/outcome; (5) treated cases; (6) no measure of risk estimates; (7) no confidence intervals/exact p values and (8) duplicates.

DATA EXTRACTION AND SYNTHESIS

PRISMA and MOOSE guidelines were followed in data extraction. Two-step screening was performed by two authors blinded to each other. A random-effects model was used to calculate pooled relative risk (RR).

MAIN OUTCOMES AND MEASURES

We included publications that assessed the risk of PD in individuals with vs without cancer and the risk of cancer in individuals with vs without PD.

RESULTS

A total of 63 studies and 17 994 584 participants were included. Meta-analysis generated a pooled RR of 0.82 (n=33; 95% CI 0.76 to 0.88; p<0.001) for association between PD and total cancer, 0.76 (n=21; 95% CI 0.67 to 0.85; p<0.001) for PD and smoking-related cancer and 0.92 (n=19; 95% CI 0.84 to 0.99; p=0.03) for non-smoking-related cancer. PD was associated with an increased risk of melanoma (n=29; pooled RR=1.75; 95% CI 1.43 to 2.14; p<0.001) but not for other skin cancers (n=17; pooled RR=0.90; 95% CI 0.60 to 1.34; p=0.60).

CONCLUSIONS

PD and total cancer were inversely associated. This inverse association persisted for both smoking-related and non-smoking-related cancers. PD was positively associated with melanoma. These results provide evidence for further investigations for possible mechanistic associations between PD and cancer.

PROSPERO REGISTRATION NUMBER

CRD42020162103.

Transcriptomic and Genetic Associations between Alzheimer's Disease, Parkinson's Disease, and Cancer

Simple Summary

Epidemiological studies have identified a link between neurodegenerative disorders and a reduced risk of overall cancer. Increases and decreases in the risk of site-specific cancers have also been reported. However, it is still unknown whether these associations arise due to shared genetic and molecular factors or are explained by other phenomena (e.g., biases in epidemiological studies or the use of medication). In this study, we aimed to investigate the potential molecular, genetic, and pharmacological links between Alzheimer’s and Parkinson’s diseases and a large panel of 22 cancer types. To examine the overlapping involvement of genes and pathways, we obtained differential gene expression profiles through meta-analyses of post-mortem brain tissues from Alzheimer’s and Parkinson’s disease patients, primary tumors, and tissue-matched controls, and compared them. Genetic similarities were assessed through network-based methods and the computation of genetic correlations. Finally, the potential impact of drugs indicated for each disorder in the identified associations was evaluated using transcriptomic methods. Our research extends previous work in the field by identifying new significant patterns of transcriptomic associations (direct and inverse) between Alzheimer’s disease, Parkinson’s disease, and different site-specific cancers. The results reveal significant genetic correlations between Parkinson’s disease, prostate cancer, and melanoma. In addition, to our knowledge, this is the first time that the role of drugs indicated for the treatment of both sets of disorders has been investigated in the context of their comorbid associations using transcriptomic methods.

Abstract

Alzheimer’s (AD) and Parkinson’s diseases (PD) are the two most prevalent neurodegenerative disorders in human populations. Epidemiological studies have shown that patients suffering from either condition present a reduced overall risk of cancer than controls (i.e., inverse comorbidity), suggesting that neurodegeneration provides a protective effect against cancer. Reduced risks of several site-specific tumors, including colorectal, lung, and prostate cancers, have also been observed in AD and PD. By contrast, an increased risk of melanoma has been described in PD patients (i.e., direct comorbidity). Therefore, a fundamental question to address is whether these associations are due to shared genetic and molecular factors or are explained by other phenomena, such as flaws in epidemiological studies, exposure to shared risk factors, or the effect of medications. To this end, we first evaluated the transcriptomes of AD and PD post-mortem brain tissues derived from the hippocampus and the substantia nigra and analyzed their similarities to those of a large panel of 22 site-specific cancers, which were obtained through differential gene expression meta-analyses of array-based studies available in public repositories. Genes and pathways that were deregulated in both disorders in each analyzed pair were examined. Second, we assessed potential genetic links between AD, PD, and the selected cancers by establishing interactome-based overlaps of genes previously linked to each disorder. Then, their genetic correlations were computed using cross-trait LD score regression and GWAS summary statistics data. Finally, the potential role of medications in the reported comorbidities was assessed by comparing disease-specific differential gene expression profiles to an extensive collection of differential gene expression signatures generated by exposing cell lines to drugs indicated for AD, PD, and cancer treatment (LINCS L1000). We identified significant inverse associations of transcriptomic deregulation between AD hippocampal tissues and breast, lung, liver, and prostate cancers, and between PD substantia nigra tissues and breast, lung, and prostate cancers. Moreover, significant direct (same direction) associations of deregulation were observed between AD and PD and brain and thyroid cancers, as well as between PD and kidney cancer. Several biological processes, including the immune system, oxidative phosphorylation, PI3K/AKT/mTOR signaling, and the cell cycle, were found to be deregulated in both cancer and neurodegenerative disorders. Significant genetic correlations were found between PD and melanoma and prostate cancers. Several drugs indicated for the treatment of neurodegenerative disorders and cancer, such as galantamine, selegiline, exemestane, and estradiol, were identified as potential modulators of the comorbidities observed between neurodegeneration and cancer.

Parkin: A targetable linchpin in human malignancies

Parkin, an E3 ubiquitin ligase has been found to be deregulated in a variety of human cancers. Our current understanding is endowed with strong evidences that Parkin plays crucial role in the pathogenesis of cancer by controlling/interfering with major hallmarks of cancer delineated till today. Consistent with the idea of mitophagy, the existing studies imitates the tumor suppressive potential of Parkin, resolved by its capacity to regulate cell proliferation, cell migration, angiogenesis, apoptosis and overall cellular survival. Dysfunction of Parkin has resulted in the loss of ubiquitination of cell cycle components followed by their accumulation leading to genomic instability, perturbed cell cycle and eventually tumor progression. In this review, we provide an overview of current knowledge about the critical role of Parkin in cancer development and progression and have focussed on its therapeutic implications highlighting the diagnostic and prognostic value of Parkin as a biomarker. We earnestly hope that an in-depth knowledge of Parkin will provide a linchpin to target in various cancers that will open a new door of clinical applications and therapeutics.

Parkin ubiquitinates phosphoglycerate dehydrogenase to suppress serine synthesis and tumor progression

Phosphoglycerate dehydrogenase (PHGDH), the first rate-limiting enzyme of serine synthesis, is frequently overexpressed in human cancer. PHGDH overexpression activates serine synthesis to promote cancer progression. Currently, PHGDH regulation in normal cells and cancer is not well understood. Parkin, an E3 ubiquitin ligase involved in Parkinson's disease, is a tumor suppressor. Parkin expression is frequently downregulated in many types of cancer, and its tumor-suppressive mechanism is poorly defined. Here, we show that PHGDH is a substrate for Parkin-mediated ubiquitination and degradation. Parkin interacted with PHGDH and ubiquitinated PHGDH at lysine 330, leading to PHGDH degradation to suppress serine synthesis. Parkin deficiency in cancer cells stabilized PHGDH and activated serine synthesis to promote cell proliferation and tumorigenesis, which was largely abolished by targeting PHGDH with RNA interference, CRISPR/Cas9 KO, or small-molecule PHGDH inhibitors. Furthermore, Parkin expression was inversely correlated with PHGDH expression in human breast cancer and lung cancer. Our results revealed PHGDH ubiquitination by Parkin as a crucial mechanism for PHGDH regulation that contributes to the tumor-suppressive function of Parkin and identified Parkin downregulation as a critical mechanism underlying PHGDH overexpression in cancer.

Loss of Parkinson's susceptibility gene LRRK2 promotes carcinogen-induced lung tumorigenesis

Pathological links between neurodegenerative disease and cancer are emerging. LRRK2 overactivity contributes to Parkinson’s disease, whereas our previous analyses of public cancer patient data revealed that decreased LRRK2 expression is associated with lung adenocarcinoma (LUAD). The clinical and functional relevance of LRRK2 repression in LUAD is unknown. Here, we investigated associations between LRRK2 expression and clinicopathological variables in LUAD patient data and asked whether LRRK2 knockout promotes murine lung tumorigenesis. In patients, reduced LRRK2 was significantly associated with ongoing smoking and worse survival, as well as signatures of less differentiated LUAD, altered surfactant metabolism and immunosuppression. We identified shared transcriptional signals between LRRK2-low LUAD and postnatal alveolarization in mice, suggesting aberrant activation of a developmental program of alveolar growth and differentiation in these tumors. In a carcinogen-induced murine lung cancer model, multiplex IHC confirmed that LRRK2 was expressed in alveolar type II (AT2) cells, a main LUAD cell-of-origin, while its loss perturbed AT2 cell morphology. LRRK2 knockout in this model significantly increased tumor initiation and size, demonstrating that loss of LRRK2, a key Parkinson’s gene, promotes lung tumorigenesis.

Bioinformatics and machine learning methodologies to identify the effects of central nervous system disorders on glioblastoma progression

Glioblastoma (GBM) is a common malignant brain tumor which often presents as a comorbidity with central nervous system (CNS) disorders. Both CNS disorders and GBM cells release glutamate and show an abnormality, but differ in cellular behavior. So, their etiology is not well understood, nor is it clear how CNS disorders influence GBM behavior or growth. This led us to employ a quantitative analytical framework to unravel shared differentially expressed genes (DEGs) and cell signaling pathways that could link CNS disorders and GBM using datasets acquired from the Gene Expression Omnibus database (GEO) and The Cancer Genome Atlas (TCGA) datasets where normal tissue and disease-affected tissue were examined. After identifying DEGs, we identified disease-gene association networks and signaling pathways and performed gene ontology (GO) analyses as well as hub protein identifications to predict the roles of these DEGs. We expanded our study to determine the significant genes that may play a role in GBM progression and the survival of the GBM patients by exploiting clinical and genetic factors using the Cox Proportional Hazard Model and the Kaplan-Meier estimator. In this study, 177 DEGs with 129 upregulated and 48 downregulated genes were identified. Our findings indicate new ways that CNS disorders may influence the incidence of GBM progression, growth or establishment and may also function as biomarkers for GBM prognosis and potential targets for therapies. Our comparison with gold standard databases also provides further proof to support the connection of our identified biomarkers in the pathology underlying the GBM progression.

Cancer and Parkinson's Disease: Common Targets, Emerging Hopes

Cancer and neurodegeneration are two major leading causes of morbidity and death worldwide. At first sight, the two fields do not seem to share much in common and, if anything, might be placed on opposite ends of a spectrum. Although neurodegeneration results in excessive neuronal cell death, cancer emerges from increased proliferation and resistance to cell death. Therefore, one might expect significant differences in the underlying pathophysiological mechanisms. However, the more we deepen our understanding of these two types of diseases, the more we appreciate the unexpected overlap between them. Although most epidemiological studies support an inverse association between the risk for development of neurodegenerative diseases and cancer, increasing evidence points to a positive correlation between specific types of cancer, like melanoma, and neurodegenerative diseases, like Parkinson's disease (PD). We believe that deciphering the molecular processes and pathways underlying one of these diseases may significantly increase our understanding about the other. Therefore, the identification of novel biomarkers and therapeutic approaches in cancer, may lead to improved diagnosis and treatment of neurodegeneration, and vice versa. In this Viewpoint, we summarize recent findings connecting both diseases and speculate that insights from one disease may inform on mechanisms, and help identify novel biomarkers and targets for intervention, possibly leading to improved management of both diseases. © 2020 International Parkinson and Movement Disorder Society.

Autophagy and Redox Homeostasis in Parkinson's: A Crucial Balancing Act

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated primarily from endogenous biochemical reactions in mitochondria, endoplasmic reticulum (ER), and peroxisomes. Typically, ROS/RNS correlate with oxidative damage and cell death; however, free radicals are also crucial for normal cellular functions, including supporting neuronal homeostasis. ROS/RNS levels influence and are influenced by antioxidant systems, including the catabolic autophagy pathways. Autophagy is an intracellular lysosomal degradation process by which invasive, damaged, or redundant cytoplasmic components, including microorganisms and defunct organelles, are removed to maintain cellular homeostasis. This process is particularly important in neurons that are required to cope with prolonged and sustained operational stress. Consequently, autophagy is a primary line of protection against neurodegenerative diseases. Parkinson's is caused by the loss of midbrain dopaminergic neurons (mDANs), resulting in progressive disruption of the nigrostriatal pathway, leading to motor, behavioural, and cognitive impairments. Mitochondrial dysfunction, with associated increases in oxidative stress, and declining proteostasis control, are key contributors during mDAN demise in Parkinson's. In this review, we analyse the crosstalk between autophagy and redoxtasis, including the molecular mechanisms involved and the detrimental effect of an imbalance in the pathogenesis of Parkinson's.

Uncovering cancer gene regulation by accurate regulatory network inference from uninformative data

The interactions among the components of a living cell that constitute the gene regulatory network (GRN) can be inferred from perturbation-based gene expression data. Such networks are useful for providing mechanistic insights of a biological system. In order to explore the feasibility and quality of GRN inference at a large scale, we used the L1000 data where ~1000 genes have been perturbed and their expression levels have been quantified in 9 cancer cell lines. We found that these datasets have a very low signal-to-noise ratio (SNR) level causing them to be too uninformative to infer accurate GRNs. We developed a gene reduction pipeline in which we eliminate uninformative genes from the system using a selection criterion based on SNR, until reaching an informative subset. The results show that our pipeline can identify an informative subset in an overall uninformative dataset, allowing inference of accurate subset GRNs. The accurate GRNs were functionally characterized and potential novel cancer-related regulatory interactions were identified.

Genetic parkinsonisms and cancer: a systematic review and meta-analysis

Genes associated with parkinsonism may also be implicated in carcinogenesis, but their interplay remains unclear. We systematically reviewed studies (PubMed 1967-2019) reporting gene variants associated with both parkinsonism and cancer. Somatic variants were examined in cancer samples, whereas germline variants were examined in cancer patients with both symptomatic and asymptomatic (carriers) genetic parkinsonisms. Pooled proportions were calculated with random-effects meta-analyses. Out of 9,967 eligible articles, 60 were included. Of the 28 genetic variants associated with parkinsonism, six were also associated with cancer. In cancer samples, SNCA was predominantly associated with gastrointestinal cancers, UCHL1 with breast cancer, and PRKN with head-and-neck cancers. In asymptomatic carriers, LRRK2 was predominantly associated with gastrointestinal and prostate cancers, PRKN with prostate and genitourinary tract cancers, GBA with sarcoma, and 22q11.2 deletion with leukemia. In symptomatic genetic parkinsonism, LRRK2 was associated with nonmelanoma skin cancers and breast cancers, and PRKN with head-and-neck cancers. Cancer was more often manifested in genetic parkinsonisms compared to asymptomatic carriers. These results suggest that intraindividual genetic contributions may modify the co-occurrence of cancer and neurodegeneration.

The Links between Parkinson's Disease and Cancer

Epidemiologic studies indicate a decreased incidence of most cancer types in Parkinson’s disease (PD) patients. However, some neoplasms are associated with a higher risk of occurrence in PD patients. Both pathologies share some common biological pathways. Although the etiologies of PD and cancer are multifactorial, some factors associated with PD, such as α-synuclein aggregation; mutations of PINK1, PARKIN, and DJ-1; mitochondrial dysfunction; and oxidative stress can also be involved in cancer proliferation or cancer suppression. The main protein associated with PD, i.e., α-synuclein, can be involved in some types of neoplastic formations. On the other hand, however, its downregulation has been found in the other cancers. PINK1 can act as oncogenic or a tumor suppressor. PARKIN dysfunction may lead to some cancers’ growth, and its expression may be associated with some tumors’ suppression. DJ-1 mutation is involved in PD pathogenesis, but its increased expression was found in some neoplasms, such as melanoma or breast, lung, colorectal, uterine, hepatocellular, and nasopharyngeal cancers. Both mitochondrial dysfunction and oxidative stress are involved in PD and cancer development. The aim of this review is to summarize the possible associations between PD and carcinogenesis.

High expression of MKK3 is associated with worse clinical outcomes in African American breast cancer patients

BACKGROUND

African American women experience a twofold higher incidence of triple-negative breast cancer (TNBC) and are 40% more likely to die from breast cancer than women of other ethnicities. However, the molecular bases for the survival disparity in breast cancer remain unclear, and no race-specific therapeutic targets have been proposed. To address this knowledge gap, we performed a systematic analysis of the relationship between gene mRNA expression and clinical outcomes determined for The Cancer Genome Atlas (TCGA) breast cancer patient cohort.

METHODS

The systematic differential analysis of mRNA expression integrated with the analysis of clinical outcomes was performed for 1055 samples from the breast invasive carcinoma TCGA PanCancer cohorts. A deep learning fully-convolutional model was used to determine the association between gene expression and tumor features based on breast cancer patient histopathological images.

RESULTS

We found that more than 30% of all protein-coding genes are differentially expressed in White and African American breast cancer patients. We have determined a set of 32 genes whose overexpression in African American patients strongly correlates with decreased survival of African American but not White breast cancer patients. Among those genes, the overexpression of mitogen-activated protein kinase kinase 3 (MKK3) has one of the most dramatic and race-specific negative impacts on the survival of African American patients, specifically with triple-negative breast cancer. We found that MKK3 can promote the TNBC tumorigenesis in African American patients in part by activating of the epithelial-to-mesenchymal transition induced by master regulator MYC.

CONCLUSIONS

The poor clinical outcomes in African American women with breast cancer can be associated with the abnormal elevation of individual gene expression. Such genes, including those identified and prioritized in this study, could represent new targets for therapeutic intervention. A strong correlation between MKK3 overexpression, activation of its binding partner and major oncogene MYC, and worsened clinical outcomes suggests the MKK3-MYC protein-protein interaction as a new promising target to reduce racial disparity in breast cancer survival.

Bidirectional Relation Between Parkinson's Disease and Glioblastoma Multiforme

Cancer and Parkinson's disease (PD) define two disease entities that include opposite concepts. Indeed, the involved mechanisms are at different ends of a spectrum related to cell survival - one due to enhanced cellular proliferation and the other due to premature cell death. There is increasing evidence indicating that patients with neurodegenerative diseases like PD have a reduced incidence for most cancers. In support, epidemiological studies demonstrate an inverse association between PD and cancer. Both conditions apparently can involve the same set of genes, however, in affected tissues the expression was inversely regulated: genes that are down-regulated in PD were found to be up-regulated in cancer and vice versa, for example p53 or PARK7. When comparing glioblastoma multiforme (GBM), a malignant brain tumor with poor overall survival, with PD, astrocytes are dysregulated in both diseases in opposite ways. In addition, common genes, that are involved in both diseases and share common key pathways of cell proliferation and metabolism, were shown to be oppositely deregulated in PD and GBM. Here, we provide an overview of the involvement of PD- and GBM-associated genes in common pathways that are dysregulated in both conditions. Moreover, we illustrate why the simultaneous study of PD and GBM regarding the role of common pathways may lead to a deeper understanding of these still incurable conditions. Eventually, considering the inverse regulation of certain genes in PD and GBM will help to understand their mechanistic basis, and thus to define novel target-based strategies for causative treatments.

Skin Cancer May Delay Onset but Not Progression of Parkinson's Disease: A Nested Case-Control Study

Objective: To evaluate the extent to which cancer, a biological opposite to neurodegenerative disorders, may affect the onset and progression of Parkinson's disease (PD). Methods: A nested case-control design in consecutive PD patients with (cases) vs. without (controls) cancer was used to compare time to clinical diagnosis and time to Hoehn & Yahr (H&Y) staging score ≥ 3 as a measure of progression. Further, we compared PD onset and progression between cases with cancer diagnosis before (cancer before PD group) and after (cancer after PD group) PD onset. Independent variables were age at PD onset, motor subscale of the Movement Disorders Society-Unified Parkinson's Disease Rating Scale, sex, cognitive impairment, falls, depression, anxiety, dementia, and autonomic symptoms. Time to H&Y ≥ 3 was determined using Cox proportional hazards, with adjusted results summarized as hazards ratio (HR). Group differences were evaluated using unpaired t-test or Fisher's exact test. Results: The clinical PD onset was later in cases vs. controls (median 67.2 vs. 59.8 years; p < 0.001), but the adjusted time to H&Y ≥ 3 was similar between groups (HR = 0.67; p = 0.13). Skin cancers constituted 75% of all cancers in cases. Amongst skin cancers, compared to controls, cases had an older age at PD onset (67.8 vs. 59.8 years; p < 0.001). There was no difference in risk of progression in PD patients with skin cancer compared to controls (HR = 0.54, p = 0.09). Conclusions: Cancer, in particular of the skin, may delay the onset but not the progression of PD. Future prospective observational studies are warranted to elucidate the complex interactions between these biologically divergent disorders.

RNA-Targeted Therapies and High-Throughput Screening Methods

RNA-binding proteins (RBPs) are involved in regulating all aspects of RNA metabolism, including processing, transport, translation, and degradation. Dysregulation of RNA metabolism is linked to a plethora of diseases, such as cancer, neurodegenerative diseases, and neuromuscular disorders. Recent years have seen a dramatic shift in the knowledge base, with RNA increasingly being recognised as an attractive target for precision medicine therapies. In this article, we are going to review current RNA-targeted therapies. Furthermore, we will scrutinise a range of drug discoveries targeting protein-RNA interactions. In particular, we will focus on the interplay between Lin28 and let-7, splicing regulatory proteins and survival motor neuron (SMN) pre-mRNA, as well as HuR, Musashi, proteins and their RNA targets. We will highlight the mechanisms RBPs utilise to modulate RNA metabolism and discuss current high-throughput screening strategies. This review provides evidence that we are entering a new era of RNA-targeted medicine.

Functional role of WW domain-containing proteins in tumor biology and diseases: Insight into the role in ubiquitin-proteasome system

The ubiquitin-proteasome system (UPS) governs the protein degradation process and balances proteostasis and cellular homeostasis. It is a well-controlled mechanism, in which removal of the damaged or excessive proteins is essential in driving signal pathways for cell survival or death. Accumulation of damaged proteins and failure in removal may contribute to disease initiation such as in cancers and neurodegenerative diseases. In this notion, specific protein-protein interaction is essential for the recognition of targeted proteins in UPS. WW domain plays an indispensable role in the protein-protein interactions during signaling. Among the 51 WW domain-containing proteins in the human proteomics, near one-quarter of them are involved in the UPS, suggesting that WW domains are crucial modules for driving the protein-protein binding and subsequent ubiquitination and degradation. In this review, we detail a broad spectrum of WW domains in protein-protein recognition, signal transduction, and relevance to diseases. New perspectives in dissecting the molecular interactions are provided.

Signal Transduction Pathways in Breast Cancer: The Important Role of PI3K/Akt/mTOR

Breast cancer is the cancer with the highest prevalence in women and is the number-one cause of cancer mortality worldwide. Cell transduction is a fundamental process in the development and progression of cancer. Modifications in various cell signalling pathways promote tumour cell proliferation, progression, and survival. The PI3K/Akt/mTOR pathway is an example of that, and it is involved in growth, proliferation, survival, motility, metabolism, and immune response regulation. Activation of this pathway is one of the main causes of cancer cell resistance to antitumour therapies. This makes PI3K/Akt/mTOR signalling a crucial object of study for understanding the development and progression of this disease. Thus, this pathway may have a role as a potential therapeutic target, as well as prognostic and diagnostic value, in patients with breast cancer. Despite the existence of selective PI3K/Akt/mTOR pathway inhibitors and current clinical trials, the cellular mechanisms are not yet known. The present review aims to understand the current state of this important disease and the paths that must be forged.

Microtubule-Associated Proteins with Regulatory Functions by Day and Pathological Potency at Night

The sensing, integrating, and coordinating features of the eukaryotic cells are achieved by the complex ultrastructural arrays and multifarious functions of the cytoskeleton, including the microtubule network. Microtubules play crucial roles achieved by their decoration with proteins/enzymes as well as by posttranslational modifications. This review focuses on the Tubulin Polymerization Promoting Protein (TPPP/p25), a new microtubule associated protein, on its "regulatory functions by day and pathological functions at night". Physiologically, the moonlighting TPPP/p25 modulates the dynamics and stability of the microtubule network by bundling microtubules and enhancing the tubulin acetylation due to the inhibition of tubulin deacetylases. The optimal endogenous TPPP/p25 level is crucial for its physiological functions, to the differentiation of oligodendrocytes, which are the major constituents of the myelin sheath. Pathologically, TPPP/p25 forms toxic oligomers/aggregates with α-synuclein in neurons and oligodendrocytes in Parkinson's disease and Multiple System Atrophy, respectively; and their complex is a potential therapeutic drug target. TPPP/p25-derived microtubule hyperacetylation counteracts uncontrolled cell division. All these issues reveal the anti-mitotic and α-synuclein aggregation-promoting potency of TPPP/p25, consistent with the finding that Parkinson's disease patients have reduced risk for certain cancers.

Lemur Tyrosine Kinase 2 (LMTK2) Level Inversely Correlates with Phospho-Tau in Neuropathological Stages of Alzheimer's Disease

: Alzheimer's disease (AD) is the most common neurodegenerative dementia. Mapping the pathomechanism and providing novel therapeutic options have paramount significance. Recent studies have proposed the role of LMTK2 in AD. However, its expression pattern and association with the pathognomonic neurofibrillary tangles (NFTs) in different brain regions and neuropathological stages of AD is not clear. We performed chromogenic (CHR) LMTK2 and fluorescent phospho-tau/LMTK2 double-labelling (FDL) immunohistochemistry (IHC) on 10-10 postmortem middle frontal gyrus (MFG) and anterior hippocampus (aHPC) samples with early and late neuropathological Braak tau stages of AD. MFG in early stage was our 'endogenous control' region as it is not affected by NFTs. Semiquantitative CHR-IHC intensity scoring revealed significantly higher (p < 0.001) LMTK2 values in this group compared to NFT-affected regions. FDL-IHC demonstrated LMTK2 predominance in the endogenous control region, while phospho-tau overburden and decreased LMTK2 immunolabelling were detected in NFT-affected groups (aHPC in early and both regions in late stage). Spearman's correlation coefficient showed strong negative correlation between phospho-tau/LMTK2 signals within each group. According to our results, LMTK2 expression is inversely proportionate to the extent of NFT pathology, and decreased LMTK2 level is not a general feature in AD brain, rather it is characteristic of the NFT-affected regions.

LRRK2 Biology from structure to dysfunction: research progresses, but the themes remain the same

Since the discovery of leucine-rich repeat kinase 2 (LRRK2) as a protein that is likely central to the aetiology of Parkinson’s disease, a considerable amount of work has gone into uncovering its basic cellular function. This effort has led to the implication of LRRK2 in a bewildering range of cell biological processes and pathways, and probable roles in a number of seemingly unrelated medical conditions. In this review we summarise current knowledge of the basic biochemistry and cellular function of LRRK2. Topics covered include the identification of phosphorylation substrates of LRRK2 kinase activity, in particular Rab proteins, and advances in understanding the activation of LRRK2 kinase activity via dimerisation and association with membranes, especially via interaction with Rab29. We also discuss biochemical studies that shed light on the complex LRRK2 GTPase activity, evidence of roles for LRRK2 in a range of cell signalling pathways that are likely cell type specific, and studies linking LRRK2 to the cell biology of organelles. The latter includes the involvement of LRRK2 in autophagy, endocytosis, and processes at the trans-Golgi network, the endoplasmic reticulum and also key microtubule-based cellular structures. We further propose a mechanism linking LRRK2 dimerisation, GTPase function and membrane recruitment with LRRK2 kinase activation by Rab29. Together these data paint a picture of a research field that in many ways is moving forward with great momentum, but in other ways has not changed fundamentally. Many key advances have been made, but very often they seem to lead back to the same places.

Neuropathological characterization of Lemur tyrosine kinase 2 (LMTK2) in Alzheimer's disease and neocortical Lewy body disease

Alzheimer's disease (AD) and neocortical Lewy body disease (LBD) are the most common neurodegenerative dementias, with no available curative treatment. Elucidating pathomechanism and identifying novel therapeutic targets are of paramount importance. Lemur tyrosine kinase 2 (LMTK2) is involved in several physiological and pathological cellular processes. Herewith a neuropathological characterization is presented in AD and neocortical LBD samples using chromogenic and fluorescent LMTK2 immunohistochemistry on post-mortem brain tissues and compared them to age-matched controls (CNTs). LMTK2 immunopositivity was limited to the neuronal cytoplasm. Neurons, including tau-positive tangle-bearing ones, showed decreased chromogenic and immunofluorescent labelling in AD in every cortical layer compared to CNT and neocortical LBD. Digital image analysis was performed to measure the average immunopositivity of groups. Mean grey values were calculated for each group after measuring the grey scale LMTK2 signal intensity of each individual neuron. There was significant difference between the mean grey values of CNT vs. AD and neocortical LBD vs. AD. The moderate decrease in neocortical LBD suggests the effect of coexisting AD pathology. We provide neuropathological evidence on decreased neuronal LMTK2 immunolabelling in AD, with implications for pathogenesis.

Association between Parkinson's Disease and Risk of Cancer: A PRISMA-compliant Meta-analysis

Previous studies exploring associations between Parkinson's disease (PD) and cancer risks provided controversial results. We conducted this study to examine the association between PD and cancer risks among different cancer types in worldwide populations. We searched for articles published before August 2019 in databases PubMed, Web of Science, EMBASE, Medline, and Google Scholar. The multivariate odds ratio (OR)/relative risk (RR) and 95% confidence intervals (CI) were computed to explore associations between PD and risks of different types of cancers. The present study indicated significantly negative associations between PD and risks of all types of cancers, digestive system cancers, lung cancers, and urinary system cancers. Additionally, no significant associations were shown between PD and risks of breast cancers, reproductive system cancers, or hematological malignancies. The study showed significantly positive associations between PD and risks of skin cancers and brain cancers. In conclusion, our investigation showed that PD patients showed reduced overall cancer risk and reduced risk of some types of cancers (digestive system cancers, lung cancers, and urinary system cancers). We need further studies to explore the underlying mechanism of the association between PD and cancers.

Antiviral Therapy in Patients With Chronic Hepatitis C Is Associated With a Reduced Risk of Parkinsonism

BACKGROUND

The risk of parkinsonism after antiviral treatment against chronic hepatitis C (CHC) is unclear.

OBJECTIVES

To investigate the association between CHC and parkinsonism and the efficacy of antiviral therapy.

METHODS

Using the National Health Insurance Research Database of Taiwan from 2004 to 2012, patients with and without CHC, patients receiving pegylated interferon-based antiviral therapy, and those without such therapy were matched by age, gender, and comorbidities by propensity scores and followed for new diagnoses of parkinsonism and Parkinson's disease (PD). Multivariable Cox proportional hazards regression analyses were performed.

RESULTS

Overall, 49,342 patients with CHC were matched with 49,342 non-CHC patients. After adjustment for confounding factors, there was a significantly increased risk (31%) of parkinsonism (hazard ratio [HR] 1.306; 95% confidence interval [CI], 1.208-1.412) in those with CHC and the risk of parkinsonism requiring anti-Parkinson medication (HR 1.323; 95% CI, 1.214-1.441). Furthermore, 23,647 untreated CHC patients were matched with 23,647 patients receiving antiviral therapy. Patients receiving antiviral therapy had a significantly lower risk of developing parkinsonism (38%; HR 0.618; 95% CI, 0.498-0.765) and a reduced risk of parkinsonism requiring anti-Parkinson medication (HR 0.651; 95% CI, 0.515-0.823). In sensitivity analyses, antiviral therapy significantly reduced the risk of parkinsonism and PD after adjustment for detection, selection, disease latency biases, and competing mortality. Our results suggest successful antiviral therapy associates with a reduced risk of hepatitis C virus-related parkinsonism compared with those with treatment failure.

CONCLUSIONS

CHC infection is associated with an increased risk of parkinsonism or PD. Antiviral therapy against CHC is associated with a reduced risk of parkinsonism or PD. © 2019 International Parkinson and Movement Disorder Society.

Partition: a surjective mapping approach for dimensionality reduction

MOTIVATION

Large amounts of information generated by genomic technologies are accompanied by statistical and computational challenges due to redundancy, badly behaved data and noise. Dimensionality reduction (DR) methods have been developed to mitigate these challenges. However, many approaches are not scalable to large dimensions or result in excessive information loss.

RESULTS

The proposed approach partitions data into subsets of related features and summarizes each into one and only one new feature, thus defining a surjective mapping. A constraint on information loss determines the size of the reduced dataset. Simulation studies demonstrate that when multiple related features are associated with a response, this approach can substantially increase the number of true associations detected as compared to principal components analysis, non-negative matrix factorization or no DR. This increase in true discoveries is explained both by a reduced multiple-testing challenge and a reduction in extraneous noise. In an application to real data collected from metastatic colorectal cancer tumors, more associations between gene expression features and progression free survival and response to treatment were detected in the reduced than in the full untransformed dataset.

AVAILABILITY AND IMPLEMENTATION

Freely available R package from CRAN, https://cran.r-project.org/package=partition.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Cancer risk in patients with Parkinson's disease in South Korea: A nationwide, population-based cohort study

INTRODUCTION

The association between Parkinson's disease (PD) and cancer development is controversial, especially in Asia. Therefore, we conducted a nationwide population-based cohort study to assess the overall cancer risk and risk for specific cancers in patients with PD in Korea.

METHODS

Using data from the Korean National Health Insurance Database, we analysed 52,009 patients diagnosed with PD between 2010 and 2015 and 260,045 individuals without PD. Patients previously diagnosed with cancer were excluded. The age- and sex-matched cohorts were followed up until 2016 for cancer development. Cox proportional hazards regression models were used to evaluate the relationship between PD and cancer.

RESULTS

Patients with PD had a lower overall cancer risk (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.74-0.82) after adjustment for multiple covariates during 2,022,852.6 person-years of follow-up. Patients with PD showed significantly lower risk of laryngeal cancer (HR, 0.45; 95% CI, 0.21-0.84), gastric cancer (HR, 0.72; 95% CI, 0.63-0.82), colorectal cancer (HR, 0.675; 95% CI, 0.60-0.76), liver cancer (HR, 0.80; 95% CI, 0.67-0.95), pancreatic cancer (HR, 0.75; 95% CI, 0.62-0.91), lung cancer (HR, 0.73; 95% CI, 0.63-0.84), leukaemia (HR, 0.49; 95% CI, 0.24-0.89), uterine cervical cancer (HR, 0.64; 95% CI, 0.40-0.99) and prostate cancer (HR, 0.78; 95% CI, 0.66-0.91).

CONCLUSION

This nationwide population-based cohort study revealed that patients with PD had lower overall cancer risk and lower risk of specific cancers. Contrary to the results of the recent Asian study, this large cohort study revealed that patients with PD were less likely to develop cancer than those without PD in Korea. Our results were consistent with those of previous Western studies, despite differences in ethnicity and environment.

Loss of parkin reduces lung tumor development by blocking p21 degradation

Several epidemiological studies have demonstrated the reciprocal relationship between the development of cancer and Parkinson’s disease (PD). However, the possible mechanisms underlying this relationship remain unclear. To identify this relationship, we first compared lung tumor growth in parkin knockout (KO) mice and wild-type (WT) mice. Parkin KO mice showed decreased lung tumor growth and increased expression of p21, a cell cycle arrester, as compared with WT mice. We also found that parkin interacts with p21, resulting in its degradation; however, parkin KO, knockdown, as well as mutation (R275W or G430D) reduced the degradation of p21. We investigated whether parkin KO increases the association of p21 with proliferating cell nuclear antigen (PCNA) or CDK2 by reducing p21 degradation, and, thus, arresting the cell cycle. The interaction between p21 and PCNA or CDK2 was also enhanced by parkin knockdown, and this increased interaction induced sub G0/G1 arrest, leading to cell death. Therefore, our data indicate that parkin KO reduces the development of lung tumors via cell cycle arrest by blocking the degradation of p21. These findings suggest that PD could be associated with lower lung cancer incidence.

Parkinson's Disease is Associated with Dysregulations of a Dopamine-Modulated Gene Network Relevant to Sleep and Affective Neurobehaviors in the Striatum

In addition to the characteristic motor symptoms, Parkinson’s disease (PD) often involves a constellation of sleep and mood symptoms. However, the mechanisms underlying these comorbidities are largely unknown. We have previously reconstructed gene networks in the striatum of a population of (C57BL/6J x A/J) F2 mice and associated the networks to sleep and affective phenotypes, providing a resource for integrated analyses to investigate perturbed sleep and affective functions at the gene network level. Combining this resource with PD-relevant transcriptomic datasets from humans and mice, we identified four networks that showed elevated gene expression in PD patients, including a circadian clock and mitotic network that was altered similarly in mouse models of PD. We then utilized multiple types of omics data from public databases and linked this gene network to postsynaptic dopamine signaling in the striatum, CDK1-modulated transcriptional regulation, and the genetic susceptibility of PD. These findings suggest that dopamine deficiency, a key aspect of PD pathology, perturbs a circadian/mitotic gene network in striatal neurons. Since the normal functions of this network were relevant to sleep and affective behaviors, these findings implicate that dysregulation of functional gene networks may be involved in the emergence of non-motor symptoms in PD. Our analyses present a framework for integrating multi-omics data from diverse sources in mice and humans to reveal insights into comorbid symptoms of complex diseases.

Large left posterior fossa meningioma presenting with quadriplegia in a woman with history of carbidopa-levodopa resistant parkinsonism

A 56-year-old Afro-Trinidadian woman with a history of a carbidopa-levodopa resistance Parkinsonian-like syndrome for 2 years, presented with acute onset spastic quadriplegia and decreased responsiveness. Diagnosis involved clinical and MR-imaging correlation consistent with a large left posterior fossa meningioma. Surgical removal of the tumor led to complete reversibility of the neurological manifestations associated with cerebellar tonsillar herniation beyond the foramen magnum and mass effect on the brainstem, cerebellum and midbrain regions. Pathological findings were typical of a meningioma. This case demonstrates the association of a large left posterior fossa meningioma and carbidopalevodopa resistant parkinsonism in an Afro-Trinidadian woman who presented with acute onset acute quadriplegia and decreased responsiveness. This case reminds clinicians that patients with dopa unresponsiveness and/or acute neurological deficit or deterioration should be worked up for other possible causes and adds to the literature on the association of parkinsonism and intracranial space occupying lesions.

Role of Sonification and Rhythmic Auditory Cueing for Enhancing Gait Associated Deficits Induced by Neurotoxic Cancer Therapies: A Perspective on Auditory Neuroprosthetics

Patients undergoing chemotherapy, radiotherapy, and immunotherapy experience neurotoxic changes in the central and peripheral nervous system. These neurotoxic changes adversely affect functioning in the sensory, motor, and cognitive domains. Thereby, considerably affecting autonomic activities like gait and posture. Recent evidence from a range of systematic reviews and meta-analyses have suggested the beneficial influence of music-based external auditory stimulations i.e., rhythmic auditory cueing and real-time auditory feedback (sonification) on gait and postural stability in population groups will balance disorders. This perspective explores the conjunct implications of auditory stimulations during cancer treatment to simultaneously reduce gait and posture related deficits. Underlying neurophysiological mechanisms by which auditory stimulations might influence motor performance have been discussed. Prompt recognition of this sensorimotor training strategy in future studies can have a widespread impact on patient care in all areas of oncology.

T cell dysfunction in chronic hepatitis B infection and liver cancer: evidence from transcriptome analysis

BACKGROUND

T cell dysfunction occurs in many diseases, especially in chronic virus infection and cancers. However, up to now, little is known on the distinctions in T cell exhaustion between cancer and chronic virus infection. The objective of this study is to explore the transcriptional similarities and differences in exhausted CD8 +T cell between chronic hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC).

METHODS

RNA sequencing was performed to compare the transcriptome of CD8 +T cells isolated from healthy donors' blood, tumour tissues of patients with HCC and chronic HBV infected HCC patients' paracancerous tissues. DESeq2 algorithm was used to determine differentially expressed genes. Gene ontology and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis was conducted for in-depth analysis of these differentially expressed genes.

RESULTS

A total number of 2109 and 2203 genes were differentially expressed in patients with chronic HBV infection and HCC, respectively. Comparing these two groups of differentially deregulated genes, we found that nearly half of them were shared, and these shared genes were further classified into several functional categories, such as metabolic process, binding and intracellular organelle. KEGG analysis revealed that these shared deregulated genes were involved in many important pathways such as Parkinson's disease, oxidative phosphorylation and messenger RNA surveillance. Interestingly, we reported that chronic HBV infection specific deregulated genes were mainly enriched in graft versus host disease, allograft rejection, phenylalanine, tyrosine and tryptophan biosynthesis pathways. Whereas, HCC-specific deregulated genes were highly enriched in oxidative phosphorylation, thyroid cancer and endometrial cancer pathways.

CONCLUSION

Our study demonstrated that T cell dysfunction associated with HCC and chronic HBV infection shares high similarities, however, each possesses its own features in terms of specific genes and signalling pathways. Uncovering the differences of T cells dysfunction would facilitate our understanding the diseases pathogenesis and developing innovative therapies in the future.