Mechanisms of Action of the US Food and Drug Administration-Approved Antisense Oligonucleotide Drugs.

Antisense oligonucleotides (ASOs) are single stranded nucleic acids that target RNA. The US Food and Drug Administration has approved ASOs for several diseases. ASOs utilize three principal modes of action (MOA). The first MOA is initiated by base-pairing between the ASO and its target mRNA, followed by RNase H-dependent mRNA degradation. The second MOA is triggered by ASOs that occlude splice acceptor sites in pre-mRNAs leading to skipping of a mutation-bearing exon. The third MOA involves ASOs that sterically hinder mRNA function, often inhibiting translation. ASOs contain a variety of modifications to the sugar-phosphate backbone and bases that stabilize the ASO or render them resistant to RNase activity. RNase H-dependent ASOs include inotersen and eplontersen (for hereditary transthyretin amyloidosis), fomiversen (for opportunistic cytomegalovirus infection), mipomersen (for familial hypercholesterolemia), and tofersen [for amyotrophic lateral sclerosis (ALS)]. Splice modulating ASOs include nursinersen (for spinal muscular atrophy) and eteplirsen, golodirsen, viltolarsen, and casimersen (all for the treatment of Duchenne muscular dystrophy). In addition, a designer ASO, milasen, was used to treat a single individual afflicted with Batten disease. Since ASO design relies principally upon knowledge of mRNA sequence, the bench to bedside pipeline for ASOs is expedient compared with protein-directed drugs. [Graphical abstract available.].

Targeting the Liver with Nucleic Acid Therapeutics for the Treatment of Systemic Diseases of Liver Origin.

Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, α-1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.

Effect of concurrent beta-blocker use in patients receiving immune checkpoint inhibitors for advanced solid tumors.

PURPOSE: Stress-induced adrenergic signaling can suppress the immune system. In animal models, pharmacological beta-blockade stimulates CD8 + T-cell activity and improves clinical activity of immune checkpoint blockade (ICB) in inhibiting tumor growth. Herein, we investigated the effect of BB on clinical outcomes of patients receiving ICB in advanced solid tumors. METHODS: We retrospectively evaluated patients with solid tumors treated with ICB at our institution from January 1, 2011 to April 28, 2017. The primary clinical outcome was disease control. Secondary clinical outcomes were overall survival (OS), and duration of therapy (DoT). The primary predictor was use of BB. Association between disease control status and BB use was assessed in univariable and multivariable logistic regression. OS was calculated using hazard ratios of BB-recipient patients vs. BB non-recipient patients via Cox proportional hazards regression models. All tests were two-sided at a significance level of 0.05. RESULTS: Of 339 identified patients receiving ICB, 109 (32%) also received BB. In covariate-adjusted analysis, odds of disease control were significantly higher among BB recipients compared to BB-non-recipients (2.79; [1.54-5.03]; P = 0.001). While we did not observe significant association of OS with the use of BB overall, significant association with better OS was observed for the urothelial carcinoma cohort (HR: 0.24; [0.09, 0.62]; P = 0.0031). CONCLUSIONS: Concurrent use of BB may enhance the clinical activity of ICB and influence overall survival, particularly in patients with urothelial carcinoma. Our findings warrant further investigation to understand the interaction of beta adrenergic signaling and antitumor immune activity and explore a combination strategy.

Simultaneous Targeting of Multiple oncomiRs with Phosphorothioate or PNA-Based Anti-miRs in Lymphoma Cell Lines.

PURPOSE: MicroRNAs (miRNAs) are short (~ 22 nts) RNAs that regulate gene expression via binding to mRNA. MiRNAs promoting cancer are known as oncomiRs. Targeting oncomiRs is an emerging area of cancer therapy. OncomiR-21 and oncomiR-155 are highly upregulated in lymphoma cells, which are dependent on these oncomiRs for survival. Targeting specific miRNAs and determining their effect on cancer cell progression and metastasis have been the focus of various studies. Inhibiting a single miRNA can have a limited effect, as there may be other overexpressed miRNAs present that may promote tumor proliferation. Herein, we target miR-21 and miR-155 simultaneously using nanoparticles delivered two different classes of antimiRs: phosphorothioates (PS) and peptide nucleic acids (PNAs) and compared their efficacy in lymphoma cell lines. METHODS: Poly-Lactic-co-Glycolic acid (PLGA) nanoparticles (NPs) containing PS and PNA-based antimiR-21 and -155 were formulated, and comprehensive NP characterizations: morphology (scanning electron microscopy), size (differential light scattering), and surface charge (zeta potential) were performed. Cellular uptake analysis was performed using a confocal microscope and flow cytometry analysis. The oncomiR knockdown and the effect on downstream targets were confirmed by gene expression (real time-polymerase chain reaction) assay. RESULTS: We demonstrated that simultaneous targeting with NP delivered PS and PNA-based antimiRs resulted in significant knockdown of miR-21 and miR-155, as well as their downstream target genes followed by reduced cell viability ex vivo. CONCLUSIONS: This project demonstrated that targeting miRNA-155 and miR-21 simultaneously using nanotechnology and a diverse class of antisense oligomers can be used as an effective approach for lymphoma therapy.

Clinical factors associated with outcome in solid tumor patients treated with immune-checkpoint inhibitors: a single institution retrospective analysis.

OBJECTIVES: Response to immune checkpoint inhibitor (ICI) remains limited to a subset of patients and predictive biomarkers of response remains an unmet need, limiting our ability to provide precision medicine. Using real-world data, we aimed to identify potential clinical prognosticators of ICI response in solid tumor patients. METHODS: We conducted a retrospective analysis of all solid tumor patients treated with ICIs at the Mount Sinai Hospital between January 2011 and April 2017. Predictors assessed included demographics, performance status, co-morbidities, family history of cancer, smoking status, cancer type, metastatic pattern, and type of ICI. Outcomes evaluated include progression free survival (PFS), overall survival (OS), overall response rate (ORR) and disease control rate (DCR). Univariable and multivariable Cox proportional hazard models were constructed to test the association of predictors with outcomes. RESULTS: We identified 297 ICI-treated patients with diagnosis of non-small cell lung cancer (N = 81, 27.3%), melanoma (N = 73, 24.6%), hepatocellular carcinoma (N = 51, 17.2%), urothelial carcinoma (N = 51, 17.2%), head and neck squamous cell carcinoma (N = 23, 7.7%), and renal cell carcinoma (N = 18, 6.1%). In multivariable analysis, good performance status of ECOG ≤ 2 (PFS, ORR, DCR and OS) and family history of cancer (ORR and DCR) associated with improved ICI response. Bone metastasis was associated with worse outcomes (PFS, ORR, and DCR). CONCLUSIONS: Mechanisms underlying the clinical predictors of response observed in this real-world analysis, such as genetic variants and bone metastasis-tumor microenvironment, warrant further exploration in larger studies incorporating translational endpoints. Consistently positive clinical correlates may help inform patient stratification when considering ICI therapy.

The Impact of Androgen Deprivation Therapy on COVID-19 Illness in Men With Prostate Cancer.

BACKGROUND: TMPRSS2, a cell surface protease regulated by androgens and commonly upregulated in prostate cancer (PCa), is a necessary component for SARS-CoV-2 viral entry into respiratory epithelial cells. Previous reports suggested a lower risk of SARS-CoV-2 among PCa patients on androgen deprivation therapy (ADT). However, the impact of ADT on severe COVID-19 illness is poorly understood. METHODS: We performed a multicenter study across 7 US medical centers and evaluated patients with PCa and SARS-CoV-2 detected by polymerase-chain-reaction between March 1, 2020, and May 31, 2020. PCa patients were considered on ADT if they had received appropriate ADT treatment within 6 months of COVID-19 diagnosis. We used multivariable logistic and Cox proportional-hazard regression models for analysis. All statistical tests were 2-sided. RESULTS: We identified 465 PCa patients (median age = 71 years) with a median follow-up of 60 days. Age, body mass index, cardiovascular comorbidity, and PCa clinical disease state adjusted overall survival (hazard ratio [HR] = 1.16, 95% confidence interval [CI] = 0.68 to 1.98, P = .59), hospitalization status (HR = 0.96, 95% CI = 0.52 to 1.77, P = .90), supplemental oxygenation (HR 1.14, 95% CI = 0.66 to 1.99, P = .64), and use of mechanical ventilation (HR = 0.81, 95% CI = 0.25 to 2.66, P = .73) were similar between ADT and non-ADT cohorts. Similarly, the addition of androgen receptor-directed therapy within 30 days of COVID-19 diagnosis to ADT vs ADT alone did not statistically significantly affect overall survival (androgen receptor-directed therapy: HR = 1.27, 95% CI = 0.69 to 2.32, P = .44). CONCLUSIONS: In this retrospective cohort of PCa patients, the use of ADT was not demonstrated to influence severe COVID-19 outcomes, as defined by hospitalization, supplemental oxygen use, or death. Age 70 years and older was statistically significantly associated with a higher risk of developing severe COVID-19 disease.

Long Noncoding RNAs Hepatocyte Nuclear Factor 4A Antisense RNA 1 and Hepatocyte Nuclear Factor 1A Antisense RNA 1 Are Involved in Ritonavir-Induced Cytotoxicity in Hepatoma Cells.

Ritonavir (RTV), a pharmacoenhancer used in anti-HIV regimens, can induce liver damage. RTV is primarily metabolized by cytochrome P450 3A4 (CYP3A4) in the liver. HNF4A antisense RNA 1 (HNF4A-AS1) and HNF1A antisense RNA 1 (HNF1A-AS1) are long noncoding RNAs that regulate the expression of pregnane X receptor (PXR) and CYP3A4. This study investigated the role and underlying mechanisms of HNF4A-AS1 and HNF1A-AS1 in RTV-induced hepatotoxicity. HNF4A-AS1 and HNF1A-AS1 were knocked down by small hairpin RNAs in Huh7 and HepG2 cells. Lactate dehydrogenase and reactive oxygen species assays were performed to assess RTV-induced hepatotoxicity. Chromatin immunoprecipitation quantitative real-time polymerase chain reaction was used to detect PXR enrichment and histone modifications in the CYP3A4 promoter. HNF4A-AS1 knockdown increased PXR and CYP3A4 expression and exacerbated RTV-induced cytotoxicity, whereas HNF1A-AS1 knockdown generated the opposite phenotype. Mechanistically, enrichment of PXR and trimethylation of histone 3 lysine 4 (H3K4me3) in the CYP3A4 promoter was increased, and trimethylation of histone 3 lysine 27 (H3K27me3) was decreased after HNF4A-AS1 knockdown. However, PXR and H3K4me3 enrichment decreased after HNF1A-AS1 knockdown. Alterations in RTV-induced hepatotoxicity caused by decreasing HNF4A-AS1 or HNF1A-AS1 were reversed by knockdown or overexpression of PXR. Increased susceptibility to RTV-induced liver injury caused by the PXR activator rifampicin was attenuated by HNF4A-AS1 overexpression or HNF1A-AS1 knockdown. Taken together, these results revealed that HNF4A-AS1 and HNF1A-AS1 modulated RTV-induced hepatotoxicity by regulating CYP3A4 expression, primarily by affecting the binding of PXR and histone modification status in the CYP3A4 promoter. SIGNIFICANCE STATEMENT: HNF4A-AS1 and HNF1A-AS1, transcribed separately from neighboring antisense genes of the human transcription factor genes HNF4A and HNF1A, were identified as long noncoding RNAs that can affect RTV-induced hepatotoxicity and susceptibility to RTV-induced hepatotoxicity caused by rifampicin exposure, mainly by affecting the expression of CY3A4 via alterations in PXR enrichment and histone modification status in the CYP3A4 promoter. This discovery provides directions for further research on the mechanisms of RTV-induced liver injury.

Characterizing Prostate-Specific Antigen Levels at Death in Patients with Metastatic Castration-Resistant Prostate Cancer: Are We Underutilizing Imaging?

BACKGROUND: Prostate-specific antigen (PSA) is a valuable prognostic and predictive biomarker in prostate cancer; however, the significance of PSA at or near the time of death is not well understood. This study aimed to characterize the significance of PSA at death in patients with metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: The Mount Sinai Genitourinary Cancer Biorepository, an institutional review board-approved, single-institution database containing all consented genitourinary cancer patients seen between 2010 and 2018, was used to identify and stratify patients into the following cohorts based on their PSA at or near death: <100 ng/mL, 100-1000 ng/mL, and >1000 ng/mL. Analyses were performed to assess clinical characteristics of disease, treatment response, and outcomes. RESULTS: We identified 1097 patients with prostate cancer, and 101 were confirmed to be deceased following a diagnosis of mCRPC. In patients with mCRPC, cohorts of higher PSA level at death were associated with lower Gleason score at diagnosis and a trend toward longer time to mCRPC and longer time from diagnosis to death, despite a higher burden of disease at death. Conversely, subgroup analysis of PSA < 10 ng/mL at death was associated with lower rates of imaging within 6 months of death, lower treatment rate, and worse clinical outcomes. CONCLUSIONS: Cohorts of different PSA levels at death in mCRPC patients showed distinct patterns of disease characteristics and clinical outcomes, likely due to the underlying molecular phenotype differences. Imaging for the patient population with very low PSA levels may be underutilized and should be considered more routinely.

The impact of the globalization of cancer clinical trials on the enrollment of Black patients.

BACKGROUND: The enrollment of Black patients in cancer clinical trials continues to trend far below the true prevalence of disease in Black patients in the United States, limiting the generalizability of trial results. A potentially overlooked contributor to the underenrollment of Black patients may be the increasing enrollment of cancer trials in countries outside the United States. However, the impact of the globalization of cancer clinical trials on recruitment of racial minority patients has been understudied. METHODS: In this study, race and accrual location data for all cancer drugs approved by the US Food and Drug Administration (FDA) between 2015 and 2018 were analyzed. A disparity score was calculated for each approval, a metric comparing Black enrollment in clinical trials with the estimated burden of disease in Black patients. RESULTS: Of 49 global clinical trials supporting 35 FDA drug approvals with race data available, Black patients accounted for 2.5% of enrollment (range, 0%-10%), with a median disparity score of 0.19 (range, 0.01-0.98). In 21 clinical trials supporting 18 FDA drug approvals with both race and accrual location data available, 64% patients were enrolled outside the United States (range, 0%-100%). Black patients accounted for 3.2% of enrollment (range, 0.2%-10%), and the median disparity score was 0.23 (range, 0.01-0.98). There was a significant inverse correlation between the proportion of trial patients enrolled outside the United States and the disparity score (Pearson correlation, -0.61; P = .007). CONCLUSIONS: The globalization of cancer clinical trials is associated with a widening racial enrollment disparity gap in the United States. The impact of global trials on domestic clinical trial generalizability warrants further consideration from a regulatory and policy standpoint. LAY SUMMARY: Black patients continue to be underrepresented in cancer clinical trials; this disparity has worsened in recent years perhaps because of the globalization of cancer clinical trials. In an analysis of demographic information from 21 cancer clinical trials leading to US Food and Drug Administration approvals between 2015 and 2018, clinical trials conducted primarily outside the United States were 2-fold less likely to enroll Black participants than US clinical trials. Thus, the globalization of cancer clinical trials may have the unintended consequence of further exacerbating existing racial disparities in cancer clinical trial representation and ultimately the generalizability of trial results.

Risk Factors for Emergency Room and Hospital Care Among Patients With Solid Tumors on Immune Checkpoint Inhibitor Therapy.

OBJECTIVES: Immune checkpoint inhibitors (ICIs) are being increasingly used across cancer types. Emergency room (ER) and inpatient (IP) care, common in patients with cancer, remain poorly defined in this specific population, and risk factors for such care are unknown. METHODS: We retrospectively reviewed charts for patients with solid tumors who received >1 ICI dose at 1 of 2 sites from January 1, 2011 to April 28, 2017. Demographics, medical history, cancer diagnosis/therapy/toxicity details, and outcomes were recorded. Descriptive data detailing ER/IP care at the 2 associated hospitals during ICI therapy (from first dose to 3 mo after last dose) were collected. The Fisher exact test and multivariate regression analysis was used to study differences between patients with versus without ER/IP care during ICI treatment. RESULTS: Among 345 patients studied, 50% had at least 1 ER visit during ICI treatment and 43% had at least 1 IP admission. Six percent of ER/IP visits eventually required intensive care. A total of 12% of ER/IP visits were associated with suspected or confirmed immune-related adverse events. Predictors of ER care were African-American race (odds ratio [OR]: 3.83, P=0.001), Hispanic ethnicity (OR: 3.12, P=0.007), and coronary artery disease (OR: 2.43, P=0.006). Predictors of IP care were African-American race (OR: 2.38, P=0.024), Hispanic ethnicity (OR: 2.29, P=0.045), chronic kidney disease (OR: 3.89, P=0.006), angiotensin converting enzyme inhibitor/angiotensin receptor blocker medication use (OR: 0.44, P=0.009), and liver metastasis (OR: 2.32, P=0.003). CONCLUSIONS: Understanding demographic and clinical risk factors for ER/IP care among patients on ICIs can help highlight disparities, prospectively identify high-risk patients, and inform preventive programs aimed at reducing such care.

Derivation and validation of a novel comorbidity-based delirium risk index to predict postoperative delirium using national administrative healthcare database.

OBJECTIVE: To derive and validate a comorbidity-based delirium risk index (DRI) to predict postoperative delirium. DATA SOURCE/STUDY SETTING: Data of 506 438 hip fracture repair surgeries from 2006 to 2016 were collected to derive DRI and perform internal validation from the Premier Healthcare Database, which provided billing information on 20-25 percent of hospitalizations in the USA. Additionally, data of 1 130 569 knee arthroplasty surgeries were retrieved for external validation. STUDY DESIGN: Thirty-six commonly seen comorbidities were evaluated by logistic regression with the outcome of postoperative delirium. The hip fracture repair surgery cohort was separated into a training dataset (60 percent) and an internal validation (40 percent) dataset. The least absolute shrinkage and selection operator (LASSO) procedure was applied for variable selection, and weights were assigned to selected comorbidities to quantify corresponding risks. The newly developed DRI was then compared to the Charlson-Deyo Index for goodness-of-fit and predictive ability, using the Akaike information criterion (AIC), Bayesian information criterion (BIC), area under the ROC curve (AUC) for goodness-of-fit, and odds ratios for predictive performance. Additional internal validation was performed by splitting the data by four regions and in 4 randomly selected hospitals. External validation was conducted in patients with knee arthroplasty surgeries. DATA COLLECTION: Hip fracture repair surgeries, knee arthroplasty surgeries, and comorbidities were identified by using ICD-9 codes. Postoperative delirium was defined by using ICD-9 codes and analyzing billing information for antipsychotics (specifically haloperidol, olanzapine, and quetiapine) typically recommended to treat delirium. PRINCIPAL FINDINGS: The derived DRI includes 14 comorbidities and assigns comorbidities weights ranging from 1 to 6. The DRI outperformed the Charlson-Deyo Comorbidity Index with better goodness-of-fit and predictive performance. CONCLUSIONS: Delirium risk index is a valid comorbidity index for covariate adjustment and risk prediction in the context of postoperative delirium. Future work is needed to test its performance in different patient populations and varying definitions of delirium.

Histone Methyltransferase G9a Regulates Expression of Nuclear Receptors and Cytochrome P450 Enzymes in HepaRG Cells at Basal Level and in Fatty Acid Induced Steatosis.

Obesity and nonalcoholic fatty liver disease (NAFLD) affect expression and function of cytochrome P450 genes (P450s). The increased expression of inflammatory cytokines is a major driver of the downregulation of P450 expression in NAFLD. Decrease in P450 expression could potentially lead to drug-drug interaction, inefficient pharmacological effect of a drug, or hepatotoxicity. An epigenetic modifier, histone 3 lysine 9 methyl transferase enzyme (G9a), known to increase histone 3 lysine 9 methylation, is downregulated in diet-induced obesity animal models. In a liver-specific G9a knockout animal model, expression of P450s was downregulated. Currently, the role of G9a in regulation of P450s in steatosis is unknown. Our hypothesis is that in steatosis G9a plays a role in downregulation of P450 expression. In this study, we used HepaRG cells to induce steatosis using a combination of free fatty acids oleic acid and palmitic acid. The G9a was knocked down and overexpressed using small interfering RNA and adenovirus mediated approaches, respectively. Knockdown and overexpression of G9a in the absence of steatosis decreased and increased expression of nuclear receptors constitutive androstane receptor (CAR), pregnane X receptor, small heterodimer partner, and CYP2B6, 2E1, 2C8, 2C9, and 3A4, respectively. In steatotic conditions, overexpression of G9a prevented fatty acid mediated decreased expression of CAR, CYP2C19, 2C8, 7A1, and 3A4. Our current study suggests that G9a might serve as a key regulator of P450 expression at both the basal level and in early steatotic conditions. Single nucleotide polymorphism of G9a leading to loss/gain of function could lead to the poor metabolizer or ultrarapid metabolizer phenotypes. SIGNIFICANCE STATEMENT: The current study demonstrates that histone modification enzyme G9a is involved in the regulation of expression of nuclear receptors constitutive androstane receptor, pregnane X receptor, and small heterodimer partner as well as drug-metabolizing cytochrome P450s (P450s) at basal conditions and in fatty acid induced cellular model of steatosis. Histone 3 lysine 9 methylation should be considered together with histone 3 lysine 4 and histone 3 lysine 27 methylation as the epigenetic mechanisms controlling gene expression of P450s.

The Roles of Long Noncoding RNAs HNF1α-AS1 and HNF4α-AS1 in Drug Metabolism and Human Diseases.

Long noncoding RNAs (lncRNAs) are RNAs with a length of over 200 nucleotides that do not have protein-coding abilities. Recent studies suggest that lncRNAs are highly involved in physiological functions and diseases. lncRNAs HNF1α-AS1 and HNF4α-AS1 are transcripts of lncRNA genes HNF1α-AS1 and HNF4α-AS1, which are antisense lncRNA genes located in the neighborhood regions of the transcription factor (TF) genes HNF1α and HNF4α, respectively. HNF1α-AS1 and HNF4α-AS1 have been reported to be involved in several important functions in human physiological activities and diseases. In the liver, HNF1α-AS1 and HNF4α-AS1 regulate the expression and function of several drug-metabolizing cytochrome P450 (P450) enzymes, which also further impact P450-mediated drug metabolism and drug toxicity. In addition, HNF1α-AS1 and HNF4α-AS1 also play important roles in the tumorigenesis, progression, invasion, and treatment outcome of several cancers. Through interacting with different molecules, including miRNAs and proteins, HNF1α-AS1 and HNF4α-AS1 can regulate their target genes in several different mechanisms including miRNA sponge, decoy, or scaffold. The purpose of the current review is to summarize the identified functions and mechanisms of HNF1α-AS1 and HNF4α-AS1 and to discuss the future directions of research of these two lncRNAs.

Development of precision medicine approaches based on inter-individual variability of BCRP/ABCG2.

Precision medicine is a rapidly-developing modality of medicine in human healthcare. Based on each patient׳s unique characteristics, more accurate dosages and drug selection can be made to achieve better therapeutic efficacy and less adverse reactions in precision medicine. A patient׳s individual parameters that affect drug transporter action can be used to develop a precision medicine guidance, due to the fact that therapeutic efficacy and adverse reactions of drugs can both be affected by expression and function of drug transporters on the cell membrane surface. The purpose of this review is to summarize unique characteristics of human breast cancer resistant protein (BCRP) and the genetic variability in the BCRP encoded gene ABCG2 in the development of precision medicine. Inter-individual variability of BCRP/ABCG2 can impact choices and outcomes of drug treatment for several diseases, including cancer chemotherapy. Several factors have been implicated in expression and function of BCRP, including genetic, epigenetic, physiologic, pathologic, and environmental factors. Understanding the roles of these factors in controlling expression and function of BCRP is critical for the development of precision medicine based on BCRP-mediated drug transport.

The HNF1α-Regulated LncRNA HNF1α-AS1 Is Involved in the Regulation of Cytochrome P450 Expression in Human Liver Tissues and Huh7 Cells.

Expression of cytochrome P450s (P450s) is regulated by epigenetic factors, such as DNA methylation, histone modifications, and noncoding RNAs through different mechanisms. Among these factors, long noncoding RNAs (lncRNAs) have been shown to play important roles in the regulation of gene expression; however, little is known about the effects of lncRNAs on the regulation of P450 expression. The aim of this study was to explore the role of lncRNAs in the regulation of P450 expression by using human liver tissues and hepatoma Huh7 cells. Through lncRNA microarray analysis and quantitative polymerase chain reaction in human liver tissues, we found that the lncRNA hepatocyte nuclear factor 1 alpha antisense 1 (HNF1α-AS1), an antisense RNA of HNF1α, is positively correlated with the mRNA expression of CYP2C8, 2C9, 2C19, 2D6, 2E1, and 3A4 as well as pregnane X receptor (PXR) and constitutive androstane receptor (CAR). Gain- and loss-of-function studies in Huh7 cells transfected with small interfering RNAs or overexpression plasmids showed that HNF1α not only regulated the expression of HNF1α-AS1 and P450s, but also regulated the expression of CAR, PXR, and aryl hydrocarbon receptor (AhR). In turn, HNF1α-AS1 regulated the expression of PXR and most P450s without affecting the expression of HNF1α, AhR, and CAR. Moreover, the rifampicin-induced expression of P450s was also affected by HNF1α and HNF1α-AS1. In summary, the results of this study suggested that HNF1α-AS1 is involved in the HNF1α-mediated regulation of P450s in the liver at both basal and drug-induced levels.

Ontogenic mRNA expression of RNA modification writers, erasers, and readers in mouse liver.

RNA modifications are recently emerged epigenetic modifications. These diverse RNA modifications have been shown to regulate multiple biological processes, including development. RNA modifications are dynamically controlled by the "writers, erasers, and readers", where RNA modifying proteins are able to add, remove, and recognize specific chemical modification groups on RNAs. However, little is known about the ontogenic expression of these RNA modifying proteins in various organs, such as liver. In the present study, the hepatic mRNA expression of selected RNA modifying proteins involve in m6A, m1A, m5C, hm5C, m7G, and Ψ modifications was analyzed using the RNA-seq technique. Liver samples were collected from male C57BL/6 mice at several ages from prenatal through neonatal, infant, child to young adult. Results showed that most of the RNA modifying proteins were highly expressed in prenatal mouse liver with a dramatic drop at birth. After birth, most of the RNA modifying proteins showed a downregulation trend during liver maturation. Moreover, the RNA modifying proteins that belong to the same enzyme family were expressed at different abundances at the same ages in mouse liver. In conclusion, this study unveils that the mRNA expression of RNA modifying proteins follows specific ontogenic expression patterns in mice liver during maturation. These data indicated that the changes in expression of RNA modifying proteins might have a potential role to regulate gene expression in liver through alteration of RNA modification status.

Fibroblast Growth Factor 15-Dependent and Bile Acid-Independent Promotion of Liver Regeneration in Mice.

The role of intestine-derived factors in promoting liver regeneration after partial hepatectomy (PHx) are not entirely known, but bile acids (BAs) and fibroblast growth factor 15 (Fgf15) that is highly expressed in the mouse ileum could promote hepatocyte proliferation. Fgf15 strongly suppresses the synthesis of BAs, and emerging evidence indicates that Fgf15 is important for liver regeneration. The mechanisms by which Fgf15 promotes liver regeneration are unclear, but Fgf15 may do so indirectly by reducing BA levels and/or directly by promoting cell proliferation. However, it remains undetermined whether these two mechanisms are independent or integrated. In this study, we aimed to clarify these relationships by generating Fgf15 Tet-Off, transgenic mice (Fgf15 Tg) that had very low BA levels as a result from overexpressed Fgf15-mediated suppression of BA synthesis. Compared with wild-type mice, the Fgf15 Tg mice showed increased hepatocyte proliferation even without surgery, and a further induction of the genes in cell-cycle progression after PHx. Moreover, overexpression of Fgf15 by adeno-associated virus (AAV)-Fgf15 transduction or treatment with the recombinant Fgf15 protein led to increased cell proliferation in vivo. Furthermore, Fgf15 Tg mice exhibited an earlier and greater activation of mitogen-activated protein kinase, signal transducer and activator of transcription 3, and NF-κB signaling pathways in the priming stage, and a disruption of the hippo signaling pathway in the termination stage of liver regeneration. Conclusion: Direct in vivo evidence demonstrates that Fgf15 is critical in stimulating the phases of priming and termination of liver regeneration that are critical for cell survival and liver-size determination, independent of BA levels. (Hepatology 2018; 00:000-000).

Stromal Cell-Derived Factor-1α Alleviates Calcium-Sensing Receptor Activation-Mediated Ischemia/Reperfusion Injury by Inhibiting Caspase-3/Caspase-9-Induced Cell Apoptosis in Rat Free Flaps.

Surgical flaps are frequently affected by ischemia/reperfusion (I/R) injury. Calcium-sensing receptor (CaSR) and stromal cell-derived factor-1α (SDF-1α) are closely associated with myocardial I/R injury. This study was performed to evaluate the feasibility of applying SDF-1α to counteract CaSR activation-mediated I/R injury in ischemic free flaps. Free flaps that underwent ischemia for 3 h were equally randomized into five groups: CaCl2, NPS2143 + CaCl2, SDF-1α + CaCl2, AMD3100 + SDF-1α + CaCl2, and normal saline. The free flaps were harvested to evaluate flap necrosis and neovascularization after 2 h or 7 d of reperfusion. p-CaSR/CaSR was extensively expressed in vascular endothelial cells of free flaps after I/R injury, and activation of the SDF-1α/CXCR4 axis and NPS2143 could reduce the expression of cleaved caspase-3, caspase-9, FAS, Cyt-c, and Bax and increase Bcl-2 expression; the opposite was true after CaSR activation. Interestingly, initiation of the SDF-1α/CXCR4 axis might abrogate CaSR activation-induced I/R injury through enhancement of microvessel density. In conclusion, CaSR might become a novel therapeutic target of free flaps affected by I/R injury. Activation of the SDF-1α/CXCR4 axis and NPS2143 could counteract CaSR activation-mediated I/R injury and promote free flap survival through inhibition of caspase-3/caspase-9-related cell apoptosis and enhancement of neovascularization.

Adherence to colonoscopy at 1 year following resection of localized colon cancer: a retrospective cohort study.

BACKGROUND: For patients with stages I-III colon cancer who have undergone surgical resection, guidelines recommend surveillance colonoscopy at 1 year. However, limited data exist on adherence and associated factors. We aimed to determine the rate of adherence to surveillance colonoscopy at 1 year among nonmetastatic colon cancer patients who underwent resection and factors associated with adherence. METHODS: In this population-based retrospective cohort study, the Surveillance, Epidemiology, and End Results (SEER)-Medicare database was used. We identified patients with stages I-III colon cancer who underwent surgical resection and survived >3 years without recurrence (no chemotherapy after 8 months) from 2002-2011. Our primary outcome was a colonoscopy claim 10-15 months after resection. We used multivariable regression analysis to assess associations between sociodemographic and clinical factors and receipt of timely colonoscopy. RESULTS: Among 28,732 patients who survived >3 years without recurrence, 7967 (28%) did not undergo colonoscopy; 12,033 (42%) had it at one year, with 3159 (11%) before 10 months and 5573 (19%) after 15 months. Decreased adherence was associated with older age; being male versus female; being black or Hispanic versus white; higher tumor stage; left-sided tumors versus right sided; and increased comorbidities. Chemotherapy receipt was associated with increased adherence (odds ratio 2.06; 95% confidence interval 1.88-2.24). CONCLUSIONS: In a large population-based sample of individuals aged ⩾ 65 years, only 42% of colon cancer survivors underwent 1-year surveillance colonoscopy. Demographic and clinical factors were associated with adherence.

Estimating global treatment toxicity burden from adverse-event data.

BACKGROUND: A summary measure that reflects the global toxicity burden of a treatment is essential for comparing therapies. Current toxicity summaries are ad hoc and do not distinguish among the severities and types of toxicities. Here a clinically feasible method for estimating the toxicity burden, based on a prospective evaluation of the toxicity profile of a randomized clinical trial of 746 prostate cancer patients conducted by SWOG, is proposed. METHODS: For 308 patients who experienced severe toxicities, 2 physicians randomly selected from 14 physicians evaluated each toxicity profile and assigned a visual analogue scale score (0-10) based on their impression of the global burden of toxicities. With mixed-effects models, severity scores and a 10-point toxicity burden score (TBS) were derived from 27 predictors accounting for severe (grade 3) and life-threatening (grade 4) toxicities for each organ class of the Common Terminology Criteria for Adverse Events. RESULTS: For most organ classes, grade 3 toxicities had a TBS of 4.14 (95% confidence interval [CI], 3.65-4.63), but infections, cardiovascular events, and pulmonary events had a higher TBS with differences of 0.87 (95% CI, 0.53-1.21), 0.88 (95% CI, 0.51-1.25), and 0.73 (95% CI, 0.22-1.24), respectively. Moreover, most grade 4 events had a higher TBS than grade 3 events, except for hemorrhaging, pain, metabolic events, and musculoskeletal events. The intrarater and interrater correlations were 0.91 and 0.59, respectively. CONCLUSIONS: The burden of toxicity grades differs with toxicity types. A TBS provides a toxicity burden summary that incorporates physicians' perspectives and differentiates between severe and life-threatening toxicities and organ classes. Cancer 2018;124:858-64. © 2017 American Cancer Society.