Influence of PSMB6 and PSMB9 Genetic Polymorphisms on Bortezomib-Based Therapy Response in Newly Diagnosed Multiple Myeloma

BACKGROUND

Bortezomib (BTZ)-based regimens play a crucial role in the treatment of multiple myeloma (MM), significantly improving patient outcomes. BTZ, a proteasome inhibitor, interferes with cellular processes essential for cancer cell growth and survival, resulting in high response rates. Its use in initial and recurrent treatment strategies has been associated with extended disease control and improved long-term outcomes, contributing to overall survival. This study aimed to delineate the clinical characteristics of newly diagnosed MM patients and investigate the influence of single nucleotide polymorphisms (SNPs) in PSMB6 and PSMB9 genes on the risk and response to BTZ-based chemotherapy, in comparison with the control group.

METHODS

This prospective study was conducted at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India, comprising 92 newly diagnosed MM cases and 92 controls. Patient selection was based on receiving first-line BTZ therapy with available outcome data. DNA was extracted from peripheral blood samples, followed by SNP analysis using real-time polymerase chain reaction (PCR) with appropriate validation and quality control measures. The patients were stratified into good responders and poor responders. The association of genetic polymorphism with the response to BTZ treatment was carried out using chi-square. Survival analysis was conducted using Kaplan-Meier to estimate the overall survival (OS) and progression-free survival (PFS).

RESULTS

In our study, the median age of participants was 55 years, with a predominant 71.7% being males. Backache (66.3%) emerged as the most commonly reported symptom in patients followed by myalgia (53.3%) and bony swelling (12%). The GA+AA genotype in PSMB6 (rs3169950) was significantly more prevalent in poor responders compared to good responders (odds ratio (OR)=3.20, p=0.011), indicating a potential genetic marker for treatment response. The presence of the GA+AA genotype in PSMB6 gene rs3169950 was significantly higher among poor responders compared to good responders (OR=3.200, p=0.011). Likewise, the GA+AA genotype of the PSMB9 gene (rs17587) was predominantly observed among poor responders (OR=3.08, p=0.011). However, no differences were noted in survival analysis.

CONCLUSION

The findings of this study represent a potential breakthrough, indicating that common genetic variants may significantly influence the development of MM and impact treatment response, providing valuable insights for predicting patient outcomes with BTZ-based therapies.

Defining the Molecular Intricacies of Human Papillomavirus-Associated Tonsillar Carcinoma

BackgroundThe past decade has shown a sharp incline in the human papillomavirus (HPV) infection associated oropharyngeal carcinoma cases, especially in men younger than 60 years old. Tonsils are one of the key sites, within the oropharyngeal region, which shows malignant changes due to HPV infection, and there is very limited literature to understand the specific dynamics in the tonsillar areas.ObjectiveThis critical review was undertaken to explore and unravel the bio-molecular interactions and the role of specific proteins associated with HPV infection induced tumorigenesis for the tonsils.DesignA systematic search of the literature was performed utilising keywords and MeSH terms related to HPV and tonsillar carcinoma in PubMed, Scopus, Embase, and Web of Science without restrictions on dates until July 2023. All studies that reported on molecular biomarkers or genes/genetic proteins in the context of HPV associated tonsillar carcinoma were included in the study.ResultsPreliminary searches revealed a total of 2734 studies of which 23 satisfied the final inclusion criteria and were included. More than 25 proteins and biomarkers were identified, and their role in the malignant process was extracted and compiled. This review also presents a short excerpt on each of the molecules identified to provide a better understanding of the pathogenesis.ConclusionGiven the rapidly increasing number of cases, there is an urgent need for more focused research on virally induced tonsillar cancers, to develop a better understanding, and for clarity of management and treatment.

Immunoproteasome Function in Normal and Malignant Hematopoiesis

The ubiquitin-proteasome system (UPS) is a central part of protein homeostasis, degrading not only misfolded or oxidized proteins but also proteins with essential functions. The fact that a healthy hematopoietic system relies on the regulation of protein homeostasis and that alterations in the UPS can lead to malignant transformation makes the UPS an attractive therapeutic target for the treatment of hematologic malignancies. Herein, inhibitors of the proteasome, the last and most important component of the UPS enzymatic cascade, have been approved for the treatment of these malignancies. However, their use has been associated with side effects, drug resistance, and relapse. Inhibitors of the immunoproteasome, a proteasomal variant constitutively expressed in the cells of hematopoietic origin, could potentially overcome the encountered problems of non-selective proteasome inhibition. Immunoproteasome inhibitors have demonstrated their efficacy and safety against inflammatory and autoimmune diseases, even though their development for the treatment of hematologic malignancies is still in the early phases. Various immunoproteasome inhibitors have shown promising preliminary results in pre-clinical studies, and one inhibitor is currently being investigated in clinical trials for the treatment of multiple myeloma. Here, we will review data on immunoproteasome function and inhibition in hematopoietic cells and hematologic cancers.

Genetic polymorphisms of proteasome subunit genes of the MHC-I antigen-presenting system are associated with cervical cancer in a Chinese Han population

Proteasome subunit beta types 8 and 9 (PSMB8, PSMB9) play critical roles in the human leukocyte antigen class I (HLA I)-presenting system. Studies have suggested that polymorphisms in the PSMB8 and PSMB9 genes may influence the immune functions of PSMB8 and PSMB9, and thus be associated with various human cancers. We investigated associations involving single nucleotide polymorphisms (SNPs) rs2071543 in PSMB8, rs1351383, rs17587 and rs2127675 in PSMB9 and risk of cervical intraepithelial neoplasia (CIN) and cervical cancer in a Chinese Han population. A total of 543 patients with CIN, 1008 patients with cervical cancer, and 1120 healthy individuals were enrolled. Agena MassArray was used for SNP genotyping of PSMB8 and PSMB9. Associations involving these SNPs and risk of CIN and cervical cancer were analysed. Our results showed that the PSMB8 T/T and T/G genotypes of rs2071543 may be associated with a higher risk of CIN (P = 0.011, OR = 1.35,95% CI: 1.07-1.70) and cervical cancer (P = 0.006, OR = 1.31, 95% CI: 1.08-1.59). For rs17587, the A allele (P = 0.001, OR = 1.303, 95% CI: 1.115-1.522), and the A/A and A/G genotypes (P = 0.001, OR = 1.36, 95% CI: 1.13-1.63) may be risk factors for cervical cancer. These results indicated that PSMB8 rs2071543 might influence susceptibility to CIN and cervical cancer, and PSMB9 rs17587 might influence cervical cancer susceptibility in a Chinese Han population.

Impact of LMP7 (rs2071543) gene polymorphism in increasing cancer risk: evidence from a meta-analysis and trial sequential analysis

Genetic variant LMP7 (low molecular weight polypeptide 7) –145 C > A may influence the function of immune surveillance of an individual and lead to cancer development. Various studies have investigated the relevance of LMP7 –145 C > A gene polymorphism with cancer risk; but, their results are conflicting and inconsistent. To obtain a comprehensive conclusion, a meta-analysis was performed by including eight eligible published studies retrieved from PubMed (Medline), EMBASE and Google Scholar web search until December 2016. Individuals with AA genotype (AA vs CC: p = 0.001; OR = 2.602, 95% CI = 1.780 to 3.803) of LMP7 -145 C > A were found to have 2 folds higher risk of cancer than those with CC genotype. The recessive genetic model (AA vs AC + CC) also indicated that individuals with AA genotype have 2 folds higher cancer risk than AC and CC genotypes (p = 0.001; OR = 2.216, 95% CI = 1.525 to 3.221). Also, significant increased cancer risk was observed in Asians but not in Caucasians. No publication bias was observed during the analysis. Trial sequential analysis also strengthened our current findings. These results suggest that genetic variant LMP7–145 C > A has significant role in increasing cancer risk in overall and Asian population, and could be useful as a prognostic marker for early cancer predisposition.

Genetic variability in LMP2 and LMP7 is associated with the risk of esophageal squamous cell carcinoma in the Kazakh population but is not associated with HPV infection

The Kazakh population in Xinjiang Province in northwestern China exhibits a high incidence of esophageal squamous cell carcinoma (ESCC). Although the etiology of esophageal carcinoma (EC) has not been elucidated, there are reports of the involvement of an immunologic mechanism. In the current study, 268 Kazakh ESCC patients and 500 age- and sex-matched control subjects were recruited. DNA was extracted from paraffin-embedded tumor specimens from the patients and peripheral blood lymphocytes from the controls and used for LMP2/LMP7 genotyping. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect LMP2/LMP7 gene single-nucleotide polymorphisms (SNPs). We found a clear increased risk of ESCC in the Kazakh population for the heterozygous LMP2 R/C genotype and the homozygous C/C genotype (OR = 1.470, 95%CI = 1.076–2.008, p = 0.015 forLMP2R/C; OR = 2.048, 95% CI = 1.168–3.591, p = 0.011 for LMP2 C/C). Conversely, the heterozygous LMP7 Q/K polymorphism was found to decrease the risk of ESCC in this population (OR = 0.421, 95% CI = 0.286–0.621, p = 8.83×10⁻⁶). Moreover, LMP2 R/C+C/C genotype was associated with increased tumor invasion depth (p = 0.041). Haplotype analysis showed that haplotype A, which includes wild-type homozygous LMP2/TAP1 and mutant LMP7, decreases susceptibility to ESCC in the Kazakh population; in contrast, haplotype E, which includes wild-type homozygous LMP2/LMP7/TAP1, acts as a risk factor for increased susceptibility to ESCC. This is the first study to report that the heterozygous LMP2 R/C and homozygous C/C genotypes increase susceptibility to ESCC in the Kazakh population and that the heterozygous LMP7 Q/K genotype decreases susceptibility to ESCC in this population. Nevertheless, neither LMP2 nor LMP7 was associated with human papillomavirus (HPV) infection. Understanding LMP2/LMP7 genetic variability will provide a new therapeutic perspective for Kazakh patients with ESCC.

Association between LMP2/LMP7 genetic variability and cancer susceptibility, especially among Asians: evidence from a meta-analysis

Low molecular mass protein (LMP) gene performs a critical role in the foreign antigen processing machine via the major histocompatibility complex-I (MHC-I) complex CD8+ cytotoxic T lymphocytes (CTL) pathway. Recent studies have reported the association of LMP2-60 G>A (rs17587) and LMP7-145 C>A (rs2071543) polymorphisms with various types of cancers, but the outcomes remained inconsistent. To obtain a reliable conclusion, we summarized available data and conducted a meta-analysis involving a total of 19 published studies. Evidences were obtained from the PubMed, Google Scholar, Web of Science and Chinese National Knowledge Infrastructure (CNKI) databases. The results demonstrated that the rs17587 and rs2071543 polymorphisms were associated with an increased cancer risk in the recessive and homozygote models. Stratified analyses by ethnicity indicated a significant association only in Asian population. Furthermore, rs17587 showed a greater susceptibility to gynecological cancers, while rs2071543 increased the risk of gastrointestinal and gynecological cancers. Our results indicate that the LMP2 rs17587 and LMP7 rs2071543 polymorphisms may act as risk factors for cancer, especially for Asian populations. Additional larger-scale multicenter studies should be performed to validate our results.

Elevated serum ferritin levels in patients with hematologic malignancies

PURPOSE

To retrospectively analyze variability and clinical significance of serum ferritin levels in Chinese patients with hematologic malignancies.

MATERIALS AND METHODS

Serum ferritin were measured by radioimmunoassay, using a kit produced by the Beijing Institute of Atomic Energy. Patients with hematologic malignancies, and treated in the Department of Hematology in Nanjing First Hospital and fulfilled study criteria were recruited.

RESULTS

Of 473 patients with hematologic malignancies, 262 patients were diagnosed with acute leukemia, 131 with lymphoma and 80 with multiple myeloma. Serum ferritin levels of newly diagnosed and recurrent patients were significantly higher than those entering complete remission stage or in the control group (p<0.001).

CONCLUSIONS

Serum ferritin lever in patients with hematologic malignancies at early stage and recurrent stage are significantly increased, so that detection and surveillance of changes of serum ferritin could be helpful in assessing conditions and prognosis of this patient cohort.

The role of the proteasome in AML

Acute myeloid leukemia (AML) is deadly hematologic malignancy. Despite a well-characterized genetic and molecular landscape, targeted therapies for AML have failed to significantly improve clinical outcomes. Over the past decade, proteasome inhibition has been demonstrated to be an effective therapeutic strategy in several hematologic malignancies. Proteasome inhibitors, such as bortezomib and carfilzomib, have become mainstays of treatment for multiple myeloma and mantle cell lymphoma. In light of this success, there has been a surge of literature exploring both the role of the proteasome and the effects of proteasome inhibition in AML. Pre-clinical studies have demonstrated that proteasome inhibition disrupts proliferative cell signaling pathways, exhibits cytotoxic synergism with other chemotherapeutics and induces autophagy of cancer-related proteins. Meanwhile, clinical trials incorporating bortezomib into combination chemotherapy regimens have reported a range of responses in AML patients, with complete remission rates >80% in some cases. Taken together, this preclinical and clinical evidence suggests that inhibition of the proteasome may be efficacious in this disease. In an effort to focus further investigation into this area, these recent studies and their findings are reviewed here.

Genetic polymorphisms associated with increased risk of developing chronic myelogenous leukemia

Little is known about inherited factors associated with the risk of developing chronic myelogenous leukemia (CML). We used a dedicated DNA chip containing 16 561 single nucleotide polymorphisms (SNPs) covering 1 916 candidate genes to analyze 437 CML patients and 1 144 healthy control individuals. Single SNP association analysis identified 139 SNPs that passed multiple comparisons (1% false discovery rate). The HDAC9, AVEN, SEMA3C, IKBKB, GSTA3, RIPK1 and FGF2 genes were each represented by three SNPs, the PSM family by four SNPs and the SLC15A1 gene by six. Haplotype analysis showed that certain combinations of rare alleles of these genes increased the risk of developing CML by more than two or three-fold. A classification tree model identified five SNPs belonging to the genes PSMB10, TNFRSF10D, PSMB2, PPARD and CYP26B1, which were associated with CML predisposition. A CML-risk-allele score was created using these five SNPs. This score was accurate for discriminating CML status (AUC: 0.61, 95%CI: 0.58-0.64). Interestingly, the score was associated with age at diagnosis and the average number of risk alleles was significantly higher in younger patients. The risk-allele score showed the same distribution in the general population (HapMap CEU samples) as in our control individuals and was associated with differential gene expression patterns of two genes (VAPA and TDRKH). In conclusion, we describe haplotypes and a genetic score that are significantly associated with a predisposition to develop CML. The SNPs identified will also serve to drive fundamental research on the putative role of these genes in CML development.

Association between LMP2 and LMP7 gene polymorphisms and the risk of gastric cancer: A case-control study

The integrality of low molecular weight protein (LMP)2/LMP7 function plays an important role in the processing of GC cell antigens. The purpose of the present hospital-based case-control study was to estimate the effect of polymorphisms in the LMP2 and LMP7 genes on the risk of GC. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to distinguish the Arg to His substitution at codon 60 of LMP2 (LMP2-60) and the Gln to Lys substitution at codon 145 of LMP7 (LMP7-145) in 502 gastric cancer patients and 502 age and gender-matched cancer-free control individuals. The Lys allele of the LMP7-145 variant was more frequent in GC patients compared with control individuals [P=0.004; adjusted odds ratio (OR), 1.39; 95% confidence interval (CI), 1.11-1.74]. The Gln/Lys and Lys/Lys genotypes increased the risk of GC compared with the Gln/Gln genotype (P=0.049 and P=0.041, respectively; adjusted OR, 1.32 and 2.13, respectively; 95% CI, 1.00-1.73 and 1.03-4.39, respectively). Compared with the Gln/Gln genotype, the LMP7-145 Gln/Lys and Lys/Lys variants of the LMP7 gene were also associated with increased susceptibility to GC (P=0.017; adjusted OR, 1.38; 95% CI, 1.06-1.80). Haplotype analysis revealed that the LMP2 (Arg)-LMP7 (Lys) haplotype was associated with increased risk of GC (P=0.013, adjusted OR=1.34, 95% CI=1.06-1.70). Stratified analysis revealed that the association between the risk of GC and the variant genotypes of LMP7-145 was stronger in older individuals (>59 years), males and non-smokers. However, no association between the LMP2-60 polymorphism and the risk of GC was observed. The present results suggest that the LMP7-145 genetic variant contributes to increased susceptibility to GC, and the Lys allele is an independent risk factor for GC.