Identification of protamine 1 as a novel cancer-testis antigen in early chronic lymphocytic leukaemia

Population-enriched innate immune variants may identify candidate gene targets at the intersection of cancer and cardio-metabolic disease

Both cancer and cardio-metabolic disease disparities exist among specific populations in the US. For example, African Americans experience the highest rates of breast and prostate cancer mortality and the highest incidence of obesity. Native and Hispanic Americans experience the highest rates of liver cancer mortality. At the same time, Pacific Islanders have the highest death rate attributed to type 2 diabetes (T2D), and Asian Americans experience the highest incidence of non-alcoholic fatty liver disease (NAFLD) and cancers induced by infectious agents. Notably, the pathologic progression of both cancer and cardio-metabolic diseases involves innate immunity and mechanisms of inflammation. Innate immunity in individuals is established through genetic inheritance and external stimuli to respond to environmental threats and stresses such as pathogen exposure. Further, individual genomes contain characteristic genetic markers associated with one or more geographic ancestries (ethnic groups), including protective innate immune genetic programming optimized for survival in their corresponding ancestral environment(s). This perspective explores evidence related to our working hypothesis that genetic variations in innate immune genes, particularly those that are commonly found but unevenly distributed between populations, are associated with disparities between populations in both cancer and cardio-metabolic diseases. Identifying conventional and unconventional innate immune genes that fit this profile may provide critical insights into the underlying mechanisms that connect these two families of complex diseases and offer novel targets for precision-based treatment of cancer and/or cardio-metabolic disease.

Peripheral Blood Mononuclear Cell derived Biomarker detection using eXplainable Artificial Intelligence (XAI) provides better diagnosis of Breast Cancer

The incidence and mortality rate of breast cancer increases yearly by an average of 1.44 % and 0.23 %, respectively. Till 2021, there were 7.8 million women who had been diagnosed with breast cancer within 5 years. Biopsies of tumors are often expensive and invasive and raise the risk of serious complications like infection, excessive bleeding, and puncture damage to nearby tissues and organs. Early detection biomarkers are often variably expressed in different patients and may even be below the detection level at an early stage. Hence PBMC that shows alteration in gene profile as a result of interaction with tumor antigens may serve as a better early detection biomarker. Also, such alterations in immune gene profile in PBMCs are more prone to detection despite variability in different breast cancer mutants.This study aimed to identify potential diagnostic biomarkers for breast cancer using eXplainable Artificial Intelligence (XAI) on XGBoost machine learning (ML) models trained on a binary classification dataset containing the expression data of PBMCs from 252 breast cancer patients and 194 healthy women.After effectively adding SHAP values further into the XGBoost model, ten important genes related to breast cancer development were discovered to be effective potential biomarkers. Our studies showed that SVIP, BEND3, MDGA2, LEF1-AS1, PRM1, TEX14, MZB1, TMIGD2, KIT, and FKBP7 are key genes that impact model prediction. These genes may serve as early, non-invasive diagnostic and prognostic biomarkers for breast cancer patients.

Protamine 1 as a secreted colorectal cancer-specific antigen facilitating G1/S phase transition under nutrient stress conditions

PURPOSE

Cancer testis antigens (CTAs) are optimal tumor diagnostic markers and involved in carcinogenesis. However, colorectal cancer (CRC) related CTAs are less reported with impressive diagnostic capability or relevance with tumor metabolism rewiring. Herein, we demonstrated CRC-related CTA, Protamine 1 (PRM1), as a promising diagnostic marker and involved in regulation of cellular growth under nutrient deficiency.

METHODS

Transcriptomics of five paired CRC tissues was used to screen CRC-related CTAs. Capability of PRM1 to distinguish CRC was studied by detection of clinical samples through enzyme linked immunosorbent assay (ELISA). Cellular functions were investigated in CRC cell lines through in vivo and in vitro assays.

RESULTS

By RNA-seq and detection in 824 clinical samples from two centers, PRM1 expression were upregulated in CRC tissues and patients` serum. Serum PRM1 showed impressive accuracy to diagnose CRC from healthy controls and benign gastrointestinal disease patients, particularly more sensitive for early-staged CRC. Furthermore, we reported that when cells were cultured in serum-reduced medium, PRM1 secretion was upregulated, and secreted PRM1 promoted CRC growth in culture and in mice. Additionally, G1/S phase transition of CRC cells was facilitated by PRM1 protein supplementation and overexpression via activation of PI3K/AKT/mTOR pathway in serum deficient medium.

CONCLUSIONS

In general, our research presented PRM1 as a specific CRC antigen and illustrated the importance of PRM1 in CRC metabolism rewiring. The new vulnerability of CRC cells was also provided with the potential to be targeted in future. Diagnostic value and grow factor-like biofunction of PRM1 A represents the secretion process of PRM1 regulated by nutrient deficiency. B represents activation of PI3K/AKT/mTOR pathway of secreted PRM1.

The expression, function, and utilization of Protamine1: a literature review

Objective

Protamine 1 (PRM1) is specific in sperm and plays essential roles in fertilization, also a member of cancer testis antigen (CTA) family. This study aims to summarize the expression and function of PRM1 in spermatogenesis, and to broaden the current knowledge and inspire future development of PRM1-based therapeutic strategies in cancer treatment and nanomedicine.

Background

The protamine proteins, are characterized by an arginine-rich core and cysteine residues. Humans express two types of protamine: PRM1 and PRM2. The abnormal expression or proportion of PRM1 and PRM2 is known to be associated with subfertility and infertility, especially for PRM1 which is highly evolutionary conserved in mammalians and expressed in all vertebrates. Biological functions of PRM1 have been unveiled in diverse cellular processes, such as tumorigenesis, somatic cell nucleus transfer, and drug delivery systems. Moreover, PRM1 is identified as a CTA in chronic leukemia (CLL) and colorectal cancer (CRC).

Methods

Literature was obtained using PubMed and the keywords protamine 1, PRM1, or P1, from January 1, 1980, through July 20, 2021. We also collect the additional evidence through screening references of articles identified through the PubMed searches.

Conclusions

PRM1 is well-studied in male infertility, and further researches and attempts to develop PRM1 as novel tumor marker, as well as drug delivery vector, will be of important clinical significance.

Impact of protamine I on colon cancer proliferation, invasion, migration, diagnosis and prognosis

This paper investigates protamine I (PRM1) expression and its effects on proliferation, invasion and migration of colon cancer cells as well as its function in clinical diagnosis and prognosis. Gene chips were used to screen differentially expressed genes. PRM1 expression was detected by Western blotting and quantitative real time-polymerase chain reaction (qRT-PCR). Hematoxylin and eosin (HE) staining and immunohistochemistry were utilized to compare the expression of PRM1 from multiple differentiation levels of colon cancer tissues. Cell viability, cell apoptosis and cell cycle were tested using the MTT assay and flow cytometry. Cell invasion and migration capability were tested using the Transwell assay and wound healing. In vivo effects of PRM1 on colon cancer were explored using a xenograft model. PRM1 expression in serum was detected by enzyme-linked immunosorbent assay (ELISA). The expression level of PRM1 was significantly higher in colon cancer tissues and the staining degree of PRM1 in poorly-differentiated was stronger. pcDNA3.1-PRM1 decreased cell apoptosis while it increased the proliferation, cell invasion and migration. The si-PRM1 group displayed an opposite tendency. The serum PRM1 level was significantly higher and could serve as a diagnostic biomarker for colon cancer.

Comparative expression profiling of testis-enriched genes regulated during the development of spermatogonial cells

The testis has been identified as the organ in which a large number of tissue-enriched genes are present. However, a large portion of transcripts related to each stage or cell type in the testis still remains unknown. In this study, databases combined with confirmatory measurements were used to investigate testis-enriched genes, localization in the testis, developmental regulation, gene expression profiles of testicular disease, and signaling pathways. Our comparative analysis of GEO DataSets showed that 24 genes are predominantly expressed in testis. Cellular locations of 15 testis-enriched proteins in human testis have been identified and most of them were located in spermatocytes and round spermatids. Real-time PCR revealed that expressions of these 15 genes are significantly increased during testis development. Also, an analysis of GEO DataSets indicated that expressions of these 15 genes were significantly decreased in teratozoospermic patients and polyubiquitin knockout mice, suggesting their involvement in normal testis development. Pathway analysis revealed that most of those 15 genes are implicated in various sperm-related cell processes and disease conditions. This approach provides effective strategies for discovering novel testis-enriched genes and their expression patterns, paving the way for future characterization of their functions regarding infertility and providing new biomarkers for specific stages of spematogenesis.

New hypotheses for large-scale epigenome alterations in somatic cancer cells: a role for male germ-cell-specific regulators

Oncogenic cell transformation is consistently associated with alterations of the cell epigenome leading to aberrant gene repression and activation. Some of these events, such as the DNA-methylation-based silencing of tumor suppressor genes, are considered to be oncogenic themselves. A much less-studied consequence of these epigenetic misregulations is the abnormal activation of tissue-specific genes in precancerous and transformed cells. Here, we explore the idea that the aberrant expression of germ-cell-specific genes in somatic cancer cells could contribute to malignant cell transformation and cancer progression. Indeed, a significant number of papers have reported the abnormal activation of germ cell-specific genes in various somatic cancers (known as cancer testis [C/T] antigens or factors). Although in most cases the physiological function of these genes remains unknown, functional investigations suggest that they can act as potent genome, epigenome and cellular reorganizers. Hence, in view of the existing literature, we discuss the hypothesis that C/T activation in somatic cells is not only a consequence of global epigenetic deregulation, but also a cause of further large-scale alterations of the epigenome, which themselves have direct oncogenic consequences for the affected cells. Finally, we highlight the fact that C/T factors have the potential to serve as valuable markers for cancer detection, as well as provide promising targets for developing new therapeutical strategies.

Cancer-testis antigens: the current status on antigen regulation and potential clinical use

Immunotherapy is theoretically an attractive therapeutic option for patients with hematological malignancies. Various laboratory studies suggested the importance of the choice of tumor antigen for successful immunotherapy. Cancer-testis antigens (CTAs) are potentially suitable molecules for tumor vaccines of hematological malignancies because of their high immunogenicity in vivo, even in cancer-bearing patients, and their relatively restricted normal tissue distribution. Tumor cell kill using a CTA-based immunotherapy will, therefore, be more specific and associated with less toxicities when compared to chemotherapy. Many CTAs have been identified in various hematologic malignancies. In this review, we will take the readers through the journey of hopes and the disappointments arisen from the discovery of CTAs. We will describe the features of CTAs and their expression in hematologic malignancies. We will also discuss the mechanisms regulating the expression of these CTAs, from a primary regulatory mechanism involving DNA methylation to secondary controls by cytokines. Finally, we will address the potential obstacles that will prevent the successful use of CTAs as targets for tumor immunotherapy.

Detection of elevated antibodies against SR protein kinase 1 in the serum of Alzheimer's disease patients

Autoantibodies targeting specific cellular antigens are often present in sera and cerebrospinal fluids (CSFs) of patients with Alzheimer's disease (AD) and could play a role in the onset and/or progression of the disease. In this study we identified SR Protein Kinase 1 (SRPK1) as a new autoantigen elevated in AD. SRPK1, the prototype of the serine/arginine family of kinases, has been implicated in the regulation of multiple cellular processes such as pre-mRNA splicing, cell proliferation, chromatin structure, nuclear import and germ cell development. Using an ELISA assay, anti-SRPK1 antibodies, targeting mainly the first catalytic domain of the kinase, were detected in sera of patients with AD, at significantly elevated levels as compared to control subjects. The findings of this study document for the first time the existence of antibodies targeting SRPK1 in human sera and are indicative of a correlation between the levels of a-SRPK1 antibodies and the incidence of AD.