Abstract
Background:
Out of 25-30% of individuals do not respond to 5-Alpha Reductase Inhibitors (5-ARI) as a primary treatment of Benign Prostatic Hyperplasia (BPH), 7% experience disease progression despite treatment. Personalized medicine, which leverages human genomics, offers an approach to tailor treatments based on individual genetic profiles, facilitating early detection of drug resistance and optimizing therapeutic strategies.
Objective:
The aim of the study was to advance personalized medicine in BPH by identifying genetic factors that influence treatment outcomes, thus improving therapeutic efficacy.
Methods:
This cohort study involved patients responsive and resistant to treatment of BPH. After prostate resection, DNA was extracted and subjected to protein sequencing. The quality of the DNA was assessed, and next-generation sequencing (NGS) was performed. The sequencing data analyzed using FastQC, Samtools, MuTect2, ANNOVAR, and VEP. Whole-genome sequencing (WGS) data were compared to the Human GRCh38 reference genome. Single nucleotide polymorphisms (SNPs) and their positions were visualized through Integrated Genomics Viewer (IGV). Statistical analyses were conducted using R software.
Result:
Two genetic variants associated with BPH, was a single nucleotide polymorphism (SNP) in the NOS3 gene at rs1799983 (T>A/G), and an SNP at rs61767072 in the SRD5A2 gene. All samples that exhibited resistance to combination drug therapy showed mutations in SNP rs61767072, specifically a deletion at base A in the SRD5A2 gene. Strong correlation reported between SNP rs61767072 and resistance to BPH combination therapy while mutations involving base A and base G in the NOS3 gene did not exhibit any significant correlation with resistance to BPH combination therapy.
Conclusion:
Variations in genetic makeup significantly affect personalized medical care. Identification of specific SNPs such as rs61767072 may be the basis for the development of more personalized therapies. This study provides evidence that pharmacogenomic approaches are needed in urology practice to improve treatment outcomes.
Keywords: BPH, Genomic, Personalized Medicine, Whole Gene Sequencing
1. BACKGROUND
Benign Prostatic Hyperplasia (BPH) is a histological diagnosis that refers to the proliferation of smooth muscle and epithelial cells within the transitional zone of the prostate (1). BPH is a common urological disease in older men worldwide. Globally, there were 94 million cases of BPH in 2019, compared to 51.1 million cases in 2000, or an increase of 70.5% in BPH cases between 2000 and 2019. Previous studies have shown that BPH contributes to increased healthcare costs and decreased quality of life. In addition, BPH is also associated with complications such as urinary tract infections. Acute urinary retention, urinary tract stones, and acute renal failure (2).
Since the 1990s, drug therapy with alpha blockers (α-blockers) and/or 5-alpha reductase inhibitors (5-ARIs) has been the first-line treatment for BPH. α-blockers are the most commonly used drugs for Lower Urinary Tract Symptoms (LUTS). Selective α-blockers such as Tamsulosin, Alfuzosin and Silodosin have been approved for the treatment of BPH. Currently, there are two 5-ARIs, finasteride and dutasteride, that can be given to patients with BPH. Combination therapy of α-blockers and 5ARIs has been shown to reduce disease progression better than using either therapy alone. Although α-blockers and 5ARIs can improve symptoms and prevent disease progression, at least 25-30% of patients do not respond and 7% of patients experience progression despite therapy (3). Our previous study showed that 10.5% patient have pharmacological therapy failure and must proceed to operative management (4).
Table 1. Mutation Detected in Every Sample.Non res: Non resistace, Res: Resistance.
| Mutation SRD5A2 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Mutation NOS3 on Base A | ||||||||||
| Mutation NOS3 on Base G | ||||||||||
| Non res 1 | Non res 2 | Non res 3 | Non res 4 | Non res 5 | Non res 6 | Non res 7 | Non res 8 | Non res 9 | Non res 10 | |
| Mutation SRD5A2 | ||||||||||
| Mutation NOS3 on Base A | ||||||||||
| Mutation NOS3 on Base G | ||||||||||
| Res 1 | Res 2 | Res 3 | Res 4 | Res 5 | Res 6 | Res 7 | Res 8 | Res 9 | Res 10 |
Several genetic markers have been associated with an increased risk of BPH and drug resistance in BPH such as steroid alpha-reductase type II (SRD5A2) (5-7). Several genes such as IRX4, ITGA6, and RFX6 are also suspected of increasing the risk of BPH (8, 9). Although several genes have been suspected of being associated with BPH therapy resistance, the mechanism is still unknown. Therefore, studies on gene mutations that cause BPH patients to become resistant to α-blocker and 5-ARI therapy are needed as predictive factors in selecting appropriate therapy for the patient’s condition. In addition, genomic variations in the Indonesian population related to BPH have not been found until now. With this study, genomic data on the Indonesian population can be obtained and the cause of resistance to BPH treatment can be identified.
2. OBJECTIVE
The aim of this study was to advance personalized medicine in BPH by identifying genetic factors that influence treatment outcomes, thus improving therapeutic efficacy.
3. MATERIAL AND METHODS
The study design was a cohort. Where patients who were resistant to the Combination of Alpha Blocker (a-Blocker) and 5-Alpha Reductase Inhibitor (5-ARI) Therapy and underwent surgery were taken postoperative scrapings and sequencing was performed. Furthermore, patient history was checked through medical records. While samples of patients who were not resistant to treatment were obtained from patients who wanted surgery at their own request, not an indication of resistance. The study was conducted in July 2024 - October 2024. The study was conducted at Saiful Anwar Hospital and the Biomolecular Laboratory of Brawijaya University. The ethical clearance committee of Saiful Anwar General Hospital accepted the research with ethical number 400/258/K.3/302/2023.
Table 2. Mutations in SRD5A2 and NOS3 and BPH Combination Drug Therapy Resistance.
| Gen | Drug Resistance | Correlation | |
|---|---|---|---|
| r | p | ||
| SRD5A2 | Combination Drug | 1.000 | <0.001 |
| NOS3 base A | Combination Drug | 0.218 | 0.335 |
| NOS3 base G | Combination Drug | 0.140 | 0.556 |
Patients with BPH resistant and responsive to treatment underwent prostate resection, followed by DNA extraction and protein sequencing. DNA was extracted, assessed for quality, and processed for sequencing. NGS was evaluated with FastQC and Samtools. Somatic variants were detected using MuTect2, and results were annotated with ANNOVAR and VEP. Data WGS was compared to Human GRCh38. SNP changes and positions were viewed through IGV. All statistical analyses were performed using R software.
4. RESULTS
In the samples we obtained, the results identified two genetic variants associated with benign prostatic hyperplasia (BPH). The first was a single nucleotide polymorphism (SNP) in the NOS3 gene at rs1799983 (T>A/G), and the second was an SNP at rs61767072 in the SRD5A2 gene. Notably, all samples that exhibited resistance to combination drug therapy showed mutations in SNP rs61767072, specifically a deletion at base A in the SRD5A2 gene.
Further data analysis exploring the relationship between phenotype and genotype revealed a strong correlation between SNP rs61767072 and resistance to BPH combination therapy (r = 1.000, p < 0.001). In contrast, mutations involving base A and base G in the NOS3 gene did not exhibit any significant correlation with resistance to BPH combination therapy. These findings highlight the crucial role of genetic mutations in determining an individual’s response to urological treatments, particularly combination therapy involving α1-blockers and 5-Alpha Reductase Inhibitors (5-ARI).
5. DISCUSSION
The pathogenesis of benign prostatic hyperplasia (BPH) is a complex process, with genetic polymorphisms playing a significant role in its development and progression. Several single nucleotide polymorphisms (SNPs) have been identified in this study as potential factors influencing the efficacy of BPH medications. Our findings indicate that genetic mutations are critical determinants of an individual’s response to urological therapy, particularly combination treatment with α1-blockers and 5-Alpha Reductase Inhibitors (5-ARI). Genotype-phenotype analysis revealed a strong association between SNP rs61767072 and resistance to combination therapy, whereas SNP rs1799983 showed no significant correlation with treatment resistance. These results suggest that genetic mutations are not merely incidental factors but may serve as key determinants of therapeutic success in BPH management.
The discovery of a mutation at the SNP position rs1799983 T>A/G in the NOS3 gene provides new insights into the genetic factors that influence the effectiveness of BPH therapy although our research showed it has unsignificant effect on BPH combination therapy. The NOS3 gene encodes endothelial nitric oxide synthase (eNOS), an enzyme responsible for producing nitric oxide (NO) in endothelial cells. NO plays a crucial role in various physiological processes, including vasodilation, smooth muscle relaxation, and blood flow regulation. In the context of the urinary tract, NO is essential for the relaxation of smooth muscle in the prostate and bladder, which allows for proper urinary flow. This smooth muscle relaxation is key in alleviating symptoms of BPH, such as urinary retention and difficulty in urination, by reducing the pressure on the urethra (11).
A mutation in the NOS3 gene, particularly at the SNP rs1799983 (T>A/G), can disrupt the normal function of eNOS. This mutation may lead to either reduced NO production or dysfunctional NO signaling, impairing the relaxation of smooth muscle cells in the prostate and surrounding tissues. As a result, despite receiving α1-blocker therapy, which is designed to relax smooth muscle in the prostate, the patient may experience suboptimal therapeutic effects. α1-blockers work by inhibiting α1-adrenergic receptors in the smooth muscle of the prostate and bladder, but their efficacy depends, in part, on the presence of effective NO signaling to enhance relaxation (12).
Testosterone, the primary androgen in males is converted to its active form DHT by 5α-reductase type 2 encoded by the SRD5A2 gene. Type 2 5α-reductase is expressed in the skin and prostate, encoded by the SRD5A2 gene located on chromosome (2). SRD5A2 activity varies in different ethnic populations, and polymorphisms in the SRD5A2 gene are reported to affect enzyme activity. SRD5A2 activity is reported to be higher in black and Asian ethnicities. Our study found that resistance to combination drugs was caused by deletions in the A base in the SRD5A2 gene. This gene is likely related to androgen metabolism or enzyme function that is affected by 5-ARI. This deletion has the potential to reduce or eliminate the effectiveness of inhibiting the conversion of testosterone to dihydrotestosterone (DHT), so that resistance to 5-ARI occurs (13).
This genetic discovery opens up the possibility for more personalized therapy for BPH patients. With genetic tests that can detect specific genetic polymorphisms, doctors can more accurately predict treatment responses and tailor therapy from the outset. Moreover, with this finding, patients who are unlikely to respond to medication can be identified early, allowing for timely surgical intervention.
6. CONCLUSION
It can be concluded that variations in genetic makeup significantly affect personalized medical care. This study provides evidence that pharmacogenomic approaches are needed in urology practice to improve treatment outcomes. Identification of specific SNPs such as rs61767072 may be the basis for the development of more personalized therapies. Thus, genetic testing before therapy can help in determining the most effective drug for patients, while reducing the risk of drug resistance.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms.
Author’s contribution:
BD: conceptualization, methodology, writing-original draft, data curation, visualization, project administration; TNB: conceptualization, methodology, writing-original draft, supervision, validation; W: conceptualization, methodology, writing-original draft, investigation, supervision, validation; DA: Conceptualization, Formal analysis, writing-original draft, EPN: Methodology, Writing – review & editing Methodology; RAE: Conceptualization, Formal analysis, Writing – review & editing Methodology.
Conflicts of interest:
The authors declare that they have no conflict of interest..
Financial support and sponsorship:
The authors report no funding.
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