Tumor subtype-specific cancer-testis antigens as potential biomarkers and immunotherapeutic targets for cancers

ACTL8 Promotes the Progression of Gastric Cancer Through PI3K/AKT/mTOR Signaling Pathway

BACKGROUND

Actin-like protein 8 (ACTL8) significantly correlates with tumor growth and prognosis across various cancer types. Nevertheless, the potential relationship between ACTL8 and gastric cancer (GC) remains uncertain.

OBJECTIVE

This study aimed to elucidate the role of ACTL8 in human GC cells and to explore its mechanism.

METHODS

Bioinformatics analysis tools, such as GEPIA2, Kaplan-Meier, and STRING, were utilized for a comprehensive investigation of the characteristics and functional roles of ACTL8 in GC, including differential expression, prognostic value, and related signaling pathways. Subsequently, gene expression analyses, cell function assays, and signaling pathway experiments were conducted to verify key findings.

RESULTS

Bioinformatics analysis showed that ACTL8 was significantly elevated in GC and closely associated with poor prognosis. Gene expression experiments confirmed the bioinformatics results. Furthermore, ACTL8 knockdown markedly reduced GC cell proliferation and inhibited migration and invasion. Mechanistically, a significant increase in the phosphorylation levels of signaling proteins was observed in GC cells following ACTL8 overexpression, and PI3K/Akt/mTOR pathway inhibitors could reverse this effect.

CONCLUSION

ACTL8 expression is significantly upregulated in GC cells and is closely correlated with poor patient prognosis. Further mechanistic studies revealed that ACTL8 may promote GC cell migration and proliferation through activation of the PI3K/Akt/mTOR signaling pathway. Consequently, ACTL8 emerges as a promising therapeutic target for GC.

The LDHC-STAT3 Signaling Network Is a Key Regulator of Basal-like Breast Cancer Cell Survival

Breast cancer treatment has evolved drastically with the addition of immunotherapy and novel targeted drugs to the current treatment options. However, achieving long-term responses with minimal adverse events remains challenging. Cancer testis antigens (CTAs) offer novel opportunities for drug development thanks to their tumor specificity, immunogenicity, pro-tumorigenic functions, and negative prognostic connotations. We previously reported that lactate dehydrogenase C (LDHC) plays a key role in regulating genomic stability and that targeting LDHC significantly improved treatment response to DNA damage response drugs in breast cancer. Here, we explored the molecular mechanisms associated with LDHC silencing in two basal-like breast cancer cell lines, MDA-MB-468 and BT-549, and a Her2-enriched breast cancer cell line, HCC-1954. Transcriptomic analyses identified the cell line-dependent differential activation of the pro-survival STAT3 pathway following LDHC depletion. While LDHC silencing significantly compromised cell survival in basal-like breast cancer cells in conjunction with a downregulation of STAT3 signaling, the opposite effect was observed in Her2-enriched breast cancer cells, which demonstrated the enhanced activation of the pro-survival STAT3 signaling pathway. The inhibition of STAT3 not only reversed the unfavorable effect of LDHC silencing in the Her2-enriched cancer cells but also demonstrated significant anti-cancer activity when used as a single agent. Our findings suggest that the LDHC-STAT3 signaling axis plays a role in regulating breast tumor cell survival in a subtype-dependent manner. Thus, LDHC-targeted therapy could be a viable therapeutic approach for a subset of breast cancer patients, particularly patients with basal-like breast cancer, whereas patients carrying Her2-enriched tumors may likely benefit more from monotherapy with STAT3 inhibitors.

Cancer testis antigens: Emerging therapeutic targets leveraging genomic instability in cancer

Cancer care has witnessed remarkable progress in recent decades, with a wide array of targeted therapies and immune-based interventions being added to the traditional treatment options such as surgery, chemotherapy, and radiotherapy. However, despite these advancements, the challenge of achieving high tumor specificity while minimizing adverse side effects continues to dictate the benefit-risk balance of cancer therapy, guiding clinical decision making. As such, the targeting of cancer testis antigens (CTAs) offers exciting new opportunities for therapeutic intervention of cancer since they display highly tumor specific expression patterns, natural immunogenicity and play pivotal roles in various biological processes that are critical for tumor cellular fitness. In this review, we delve deeper into how CTAs contribute to the regulation and maintenance of genomic integrity in cancer, and how these mechanisms can be exploited to specifically target and eradicate tumor cells. We review the current clinical trials targeting aforementioned CTAs, highlight promising pre-clinical data and discuss current challenges and future perspectives for future development of CTA-based strategies that exploit tumor genomic instability.

Cancer testis antigen burden (CTAB): a novel biomarker of tumor-associated antigens in lung cancer

BACKGROUND

Cancer-testis antigens (CTAs) are tumor antigens that are normally expressed in the testes but are aberrantly expressed in several cancers. CTA overexpression drives the metastasis and progression of lung cancer, and is associated with poor prognosis. To improve lung cancer diagnosis, prognostic prediction, and drug discovery, robust CTA identification and quantitation is needed. In this study, we examined and quantified the co-expression of CTAs in lung cancer to derive cancer testis antigen burden (CTAB), a novel biomarker of immunotherapy response.

METHODS

Formalin fixed paraffin embedded (FFPE) tumor samples in discovery cohort (n = 5250) and immunotherapy and combination therapy treated non-small cell lung cancer (NSCLC) retrospective (n = 250) cohorts were tested by comprehensive genomic and immune profiling (CGIP), including tumor mutational burden (TMB) and the mRNA expression of 17 CTAs. PD-L1 expression was evaluated by IHC. CTA expression was summed to derive the CTAB score. The median CTAB score for the discovery cohort of 170 was applied to the retrospective cohort as cutoff for CTAB "high" and "low". Biomarker and gene expression correlation was measured by Spearman correlation. Kaplan-Meier survival analyses were used to detect overall survival (OS) differences, and objective response rate (ORR) based on RECIST criteria was compared using Fisher's exact test.

RESULTS

The CTAs were highly co-expressed (p < 0.05) in the discovery cohort. There was no correlation between CTAB and PD-L1 expression (R = 0.011, p = 0.45) but some correlation with TMB (R = 0.11, p = 9.2 × 10-14). Kaplan-Meier survival analysis of the immunotherapy-treated NSCLC cohort revealed better OS for the pembrolizumab monotherapy treated patients with high CTAB (p = 0.027). The combination group demonstrated improved OS compared to pembrolizumab monotherapy group (p = 0.04). The pembrolizumab monotherapy patients with high CTAB had a greater ORR than the combination therapy group (p = 0.02).

CONCLUSIONS

CTA co-expression can be reliably measured using CGIP in solid tumors. As a biomarker, CTAB appears to be independent from PD-L1 expression, suggesting that CTAB represents aspects of tumor immunogenicity not measured by current standard of care testing. Improved OS and ORR for high CTAB NSCLC patients treated with pembrolizumab monotherapy suggests a unique underlying aspect of immune response to these tumor antigens that needs further investigation.

PRAME expression and its prognostic significance in invasive breast carcinoma

OBJECTIVES

PRAME (PReferentially expressed Antigen in MElanoma) is a carcinoma testis antigen expressed in numerous tumour types. The aim of this study was to assess PRAME expression in different surrogate subtypes of breast carcinoma and its correlation with other prognostic factors.

MATERIAL AND METHODS

A total of 220 cases of invasive breast carcinoma were selected and categorized according to ER, PgR, HER2 status, and Ki67 proliferation index in luminal A like, luminal B HER2+ like, luminal B HER2- negative like, HER2 positive like and triple-negative or basal-like. All cases were examined for PRAME expression by immunohistochemistry (IHC).

RESULTS

A PRAME-high profile was detected in 53 (24,1 %) of all examined breast carcinoma samples. A significantly higher expression of PRAME was detected in HER2-positive carcinomas (50 %) and TN breast carcinomas (40,54 %) compared to ER-positive (luminal-like) subtype of breast carcinomas (3,38 % luminal A and 15,38 % luminal B). Percentage of PRAME positive tumour cells showed positive correlation with tumor size, Ki67 proliferation index, HER2 status, nuclear grade, TILs and presence of metastasis, and negative correlation with ER status and disease-free survival (DFS).

CONCLUSION

Our study showed that HER2 positive and TN breast carcinomas more commonly express PRAME than ER positive carcinomas and that PRAME expression shows positive correlation with certain prognostic factors, however PRAME wasn't revealed as an independent prognostic factor in our study. The importance of PRAME expression in breast carcinoma lies in its potential use as an immunotherapeutic target, particularly in patients with limited therapeutic options.

Melanoma Antigen Family A (MAGE A) as Promising Biomarkers and Therapeutic Targets in Bladder Cancer

The Melanoma Antigen Gene (MAGE) is a large family of highly conserved proteins that share a common MAGE homology domain. Interestingly, many MAGE family members exhibit restricted expression in reproductive tissues but are abnormally expressed in various human malignancies, including bladder cancer, which is a common urinary malignancy associated with high morbidity and mortality rates. The recent literature suggests a more prominent role for MAGEA family members in driving bladder tumorigenesis. This review highlights the role of MAGEA proteins, the potential for them to serve as diagnostic or prognostic biomarker(s), and as therapeutic targets for bladder cancer.

Identification of pan-cancer/testis genes and validation of therapeutic targeting in triple-negative breast cancer: Lin28a-based and Siglece-based vaccination induces antitumor immunity and inhibits metastasis

BACKGROUND

Cancer-testis (CT) genes are targets for tumor antigen-specific immunotherapy given that their expression is normally restricted to the immune-privileged testis in healthy individuals with aberrant expression in tumor tissues. While they represent targetable germ tissue antigens and play important functional roles in tumorigenesis, there is currently no standardized approach for identifying clinically relevant CT genes. Optimized algorithms and validated methods for accurate prediction of reliable CT antigens (CTAs) with high immunogenicity are also lacking.

METHODS

Sequencing data from the Genotype-Tissue Expression (GTEx) and The Genomic Data Commons (GDC) databases was used for the development of a bioinformatic pipeline to identify CT exclusive genes. A CT germness score was calculated based on the number of CT genes expressed within a tumor type and their degree of expression. The impact of tumor germness on clinical outcome was evaluated using healthy GTEx and GDC tumor samples. We then used a triple-negative breast cancer mouse model to develop and test an algorithm that predicts epitope immunogenicity based on the identification of germline sequences with strong major histocompatibility complex class I (MHCI) and MHCII binding affinities. Germline sequences for CT genes were synthesized as long synthetic peptide vaccines and tested in the 4T1 triple-negative model of invasive breast cancer with Poly(I:C) adjuvant. Vaccine immunogenicity was determined by flow cytometric analysis of in vitro and in vivo T-cell responses. Primary tumor growth and lung metastasis was evaluated by histopathology, flow cytometry and colony formation assay.

RESULTS

We developed a new bioinformatic pipeline to reliably identify CT exclusive genes as immunogenic targets for immunotherapy. We identified CT genes that are exclusively expressed within the testis, lack detectable thymic expression, and are significantly expressed in multiple tumor types. High tumor germness correlated with tumor progression but not with tumor mutation burden, supporting CTAs as appealing targets in low mutation burden tumors. Importantly, tumor germness also correlated with markers of antitumor immunity. Vaccination of 4T1 tumor-bearing mice with Siglece and Lin28a antigens resulted in increased T-cell antitumor immunity and reduced primary tumor growth and lung metastases.

CONCLUSION

Our results present a novel strategy for the identification of highly immunogenic CTAs for the development of targeted vaccines that induce antitumor immunity and inhibit metastasis.

Structural and biochemical insights into the interaction mechanism underlying HORMAD1 and its partner proteins

The mammalian HORMA domain-containing protein 1 (HORMAD1) regulates DNA mismatch repair and homologous recombination (HR) repair in many cancers. Here, we show that the structure of human HORMAD1 adopts a self-closed conformation and displays an intra-molecular HORMA domain-closure motif interaction mode. Structural and biochemical data suggest that the interaction modes of the peptide motifs from HORMAD2 and MCM9 with HORMAD1 are highly similar to that of HORMAD1 own closure motif. The peptide motifs from diverse binding partners of HORMAD1 share a conserved Ser-Glu-Pro sequence. Additionally, structural comparison unveiled the HORMA-peptide motif interaction mode diversity among HORMA-containing proteins. Finally, cell-based assays revealed that this HORMA-closure motif interaction pattern contributes to DNA mismatch repair and is required for HORMAD1-dependent HR repair. Together, our results provide structural and biochemical insights into the common theme and functional plasticity of the HORMA domain-containing protein family, and also reveal a universal regulation mechanism for HORMAD1.

Immunohistochemical expression of PRAME in 485 cases of epithelial tubo-ovarian tumors

Preferentially expressed antigen of melanoma (PRAME) is a cancer/testis antigen selectively expressed in somatic tissues and various solid malignant tumors and is associated with poor prognostic outcome. Our research aimed to comprehensively compare its expression in a large cohort of tubo-ovarian epithelial tumors and examine its correlation with our clinico-pathologic data, as well as to assess its potential use in diagnostics and therapy.We examined 485 cases of epithelial tubo-ovarian tumors including 107 clear cell carcinomas (CCC), 52 endometroid carcinomas (EC), 103 high grade serous carcinomas (HGSC), 119 low grade serous carcinomas (LGSC)/micropapillary variant of serous borderline tumors (mSBT), and 104 cases of mucinous carcinomas (MC)/mucinous borderline tumors (MBT). The immunohistochemical analysis was performed using TMAs.The highest levels of expression were seen in EC (60%), HGSC (62%), and CCC (56%), while expression in LGSC/mSBT (4%) and MC/MBT (2%) was rare. The clinico-pathologic correlations and survival analysis showed no prognostic significance.The results of our study showed that PRAME is neither prognostic nor a suitable ancillary marker in the differential diagnosis of tubo-ovarian epithelial tumors. Nevertheless, knowledge about the PRAME expression may be important concerning its potential predictive significance, because targeting PRAME as a potential therapeutic option is currently under investigation.

Single-Cell Evolutionary Analysis Reveals Drivers of Plasticity and Mediators of Chemoresistance in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is often a heterogeneous tumor, where dynamic regulation of key transcription factors can drive multiple populations of phenotypically different cells which contribute differentially to tumor dynamics. This tumor is characterized by a very low 2-year survival rate, high rates of metastasis, and rapid acquisition of chemoresistance. The heterogeneous nature of this tumor makes it difficult to study and to treat, as it is not clear how or when this heterogeneity arises. Here we describe temporal, single-cell analysis of SCLC to investigate tumor initiation and chemoresistance in both SCLC xenografts and an autochthonous SCLC model. We identify an early population of tumor cells with high expression of AP-1 network genes that are critical for tumor growth. Furthermore, we have identified and validated the cancer testis antigens (CTA) PAGE5 and GAGE2A as mediators of chemoresistance in human SCLC. CTAs have been successfully targeted in other tumor types and may be a promising avenue for targeted therapy in SCLC.

IMPLICATIONS

Understanding the evolutionary dynamics of SCLC can shed light on key mechanisms such as cellular plasticity, heterogeneity, and chemoresistance.

Identification of pan-cancer/testis genes and validation of therapeutic targeting in triple-negative breast cancer: Lin28a- and Siglece-based vaccination induces anti-tumor immunity and inhibits metastasis

Background

Cancer-testis (CT) genes are targets for tumor antigen-specific immunotherapy given that their expression is normally restricted to the immune-privileged testis in healthy individuals with aberrant expression in tumor tissues. While they represent targetable germ-tissue antigens and play important functional roles in tumorigenesis, there is currently no standardized approach for identifying clinically relevant CT genes. Optimized algorithms and validated methods for accurate prediction of reliable CT antigens with high immunogenicity are also lacking.

Methods

Sequencing data from the Genotype-Tissue Expression (GTEx) and The Genomic Data Commons (GDC) databases was utilized for the development of a bioinformatic pipeline to identify CT exclusive genes. A CT germness score was calculated based on the number of CT genes expressed within a tumor type and their degree of expression. The impact of tumor germness with clinical outcome was evaluated using healthy GTEx and GDC tumor samples. We then used a triple-negative breast cancer mouse model to develop and test an algorithm that predicts epitope immunogenicity based on the identification of germline sequences with strong MHCI and MHCII binding affinities. Germline sequences for CT genes were synthesized as long synthetic peptide vaccines and tested in the 4T1 triple-negative model of invasive breast cancer with Poly(I:C) adjuvant. Vaccine immunogenicity was determined by flow cytometric analysis of in vitro and in vivo T cell responses. Primary tumor growth and lung metastasis was evaluated by histopathology, flow cytometry and colony formation assay.

Results

We developed a new bioinformatic pipeline to reliably identify CT exclusive genes as immunogenic targets for immunotherapy. We identified CT genes that are exclusively expressed within the testis, lack detectable thymic expression, and are significantly expressed in multiple tumor types. High tumor germness correlated with tumor progression but not with tumor mutation burden, supporting CT antigens as appealing targets in low mutation burden tumors. Importantly, tumor germness also correlated with markers of anti-tumor immunity. Vaccination of 4T1 tumor bearing mice with Siglece and Lin28a antigens resulted in increased T cell anti-tumor immunity and reduced primary tumor growth and lung metastases.

Conclusion

Our results present a novel strategy for the identification of highly immunogenic CT antigens for the development of targeted vaccines that induce anti-tumor immunity and inhibit metastasis.

Targeting KK-LC-1 inhibits malignant biological behaviors of triple-negative breast cancer

BACKGROUND

Cancer/testis antigens (CTAs) participate in the regulation of malignant biological behaviors in breast cancer. However, the function and mechanism of KK-LC-1, a member of the CTA family, in breast cancer are still unclear.

METHODS

Bioinformatic tools, immunohistochemistry, and western blotting were utilized to detect the expression of KK-LC-1 in breast cancer and to explore the prognostic effect of KK-LC-1 expression in breast cancer patients. Cell function assays, animal assays, and next-generation sequencing were utilized to explore the function and mechanism of KK-LC-1 in the malignant biological behaviors of triple-negative breast cancer. Small molecular compounds targeting KK-LC-1 were also screened and drug susceptibility testing was performed.

RESULTS

KK-LC-1 was significantly highly expressed in triple-negative breast cancer tissues than in normal breast tissues. KK-LC-1 high expression was related to poor survival outcomes in patients with breast cancer. In vitro studies suggested that KK-LC-1 silencing can inhibit triple-negative breast cancer cell proliferation, invasion, migration, and scratch healing ability, increase cell apoptosis ratio, and arrest the cell cycle in the G0-G1 phase. In vivo studies have suggested that KK-LC-1 silencing decreases tumor weight and volume in nude mice. Results showed that KK-CL-1 can regulate the malignant biological behaviors of triple-negative breast cancer via the MAL2/MUC1-C/PI3K/AKT/mTOR pathway. The small-molecule compound Z839878730 had excellent KK-LC-1 targeting ability and cancer cell killing ability. The EC₅₀ value was 9.7 μM for MDA-MB-231 cells and 13.67 µM for MDA-MB-468 cells. Besides, Z839878730 has little tumor-killing effect on human normal mammary epithelial cells MCF10A and can inhibit the malignant biological behaviors of triple-negative breast cancer cells by MAL2/MUC1-C/PI3K/AKT/mTOR pathway.

CONCLUSIONS

Our findings suggest that KK-LC-1 may serve as a novel therapeutic target for triple-negative breast cancer. Z839878730, which targets KK-LC-1, presents a new path for breast cancer clinical treatment.

The role of PRAME and NY-ESO-1 as potential therapeutic and prognostic biomarkers in triple-negative breast carcinomas

PRAME and NY-ESO-1 are cancer-testis antigens (CTAs) reported to be highly enriched in triple-negative breast cancers (TNBCs), against which vaccines and immunotherapies are currently being developed. This study aims to analyze PRAME and NY-ESO-1 expression in TNBCs and their correlation with clinical outcomes. This is a retrospective cohort study of TNBC patients who have undergone neoadjuvant chemotherapy. PRAME and NY-ESO-1 expression were assessed on pre-therapy biopsies as H-scores (percentage x intensity) with final H scores of 2-3 considered as positive. Association between expression and pathologic complete response (pCR), metastasis, and residual cancer burden (RCB) were assessed via logistic regression. Cox proportional hazards models were used to assess the association with progression-free survival. P-values < 0.05 were considered statistically significant. Sixty-three percent of 76 patients were positive for PRAME. In contrast, only 5 % were positive for NY-ESO-1. PRAME positivity was significantly associated with a lower likelihood of early metastatic disease (OR = 0.24, 95 % CI 0.08-0.62; P = 0.005). However, it was not significantly associated with pCR, RCB category, or progression-free survival. NY-ESO1 score was not significantly associated with early metastatic disease, pCR, RCB category, or progression-free survival. Our results suggest that PRAME positivity may be associated with a lower risk of early metastasis in TNBCs, but not with response to neoadjuvant chemotherapy or progression-free survival. The high expression of PRAME in TNBCs makes it a potential therapeutic target, while NY-ESO1 appears to be a less useful marker. However, further larger studies are needed to ascertain the utility of these markers.

Cytokines as Potential Therapeutic Targets and their Role in the Diagnosis and Prediction of Cancers

The death rate from cancer is declining as a result of earlier identification and more advanced treatments. Nevertheless, a number of unfavourable adverse effects, including prolonged, long-lasting inflammation and reduced immune function, usually coexist with anti-cancer therapies and lead to a general decline in quality of life. Improvements in standardized comprehensive therapy and early identification of a variety of aggressive tumors remain the main objectives of cancer research. Tumor markers in those with cancer are tumor- associated proteins that are clinically significant. Even while several tumor markers are routinely used, they don't always provide reliable diagnostic information. Serum cytokines are promising markers of tumor stage, prognosis, and responsiveness to therapy. In fact, several cytokines are currently proposed as potential biomarkers in a variety of cancers. It has actually been proposed that the study of circulatory cytokines together with biomarkers that are particular to cancer can enhance and accelerate cancer diagnosis and prediction, particularly via blood samples that require minimal to the absence of invasion. The purpose of this review was to critically examine relevant primary research literature in order to elucidate the role and importance of a few identified serum cytokines as prospective therapeutic targets in oncological diseases.

CPPA: A Web Tool for Exploring Proteomic and Phosphoproteomic Data in Cancer

A tremendous amount of proteomic and phosphoproteomic data has been produced over the years with the development of mass spectrometry techniques, providing us with new opportunities to explore and understand the proteome and phosphoproteome as well as the function of proteins and protein phosphorylation sites. However, a lack of powerful tools that we can utilize to explore these valuable data limits our understanding of the proteome and phosphoproteome, particularly in diseases such as cancer. To address these unmet needs, we established CPPA (Cancer Proteome and Phosphoproteome Atlas), a web tool to mine abnormalities of the proteome and phosphoproteome in cancer based on published data sets. All analysis results are presented in CPPA with a flexible web interface to provide key customization utilities, including general analysis, differential expression profiling, statistical analysis of protein phosphorylation sites, correlation analysis, similarity analysis, survival analysis, pathological stage analysis, etc. CPPA greatly facilitates the process of data mining and therapeutic target discovery by providing a comprehensive analysis of proteomic and phosphoproteomic data in normal and tumor tissues with a simple click, which helps to unlock the precious value of mass spectrometry data by bridging the gap between raw data and experimental biologists. CPPA is currently available at https://cppa.site/cppa.

Immune responses against shared antigens are common in esophago-gastric cancer and can be enhanced using CD40-activated B cells

BACKGROUND

Specific immune response is a hallmark of cancer immunotherapy and shared tumor-associated antigens (TAAs) are important targets. Recent advances using combined cellular therapy against multiple TAAs renewed the interest in this class of antigens. Our study aims to determine the role of TAAs in esophago-gastric adenocarcinoma (EGA).

METHODS

RNA expression was assessed by NanoString in tumor samples of 41 treatment-naïve EGA patients. Endogenous T cell and antibody responses against the 10 most relevant TAAs were determined by FluoroSpot and protein-bound bead assays. Digital image analysis was used to evaluate the correlation of TAAs and T-cell abundance. T-cell receptor sequencing, in vitro expansion with autologous CD40-activated B cells (CD40Bs) and in vitro cytotoxicity assays were applied to determine specific expansion, clonality and cytotoxic activity of expanded T cells.

RESULTS

68.3% of patients expressed ≥5 TAAs simultaneously with coregulated clusters, which were similar to data from The Cancer Genome Atlas (n=505). Endogenous cellular or humoral responses against ≥1 TAA were detectable in 75.0% and 53.7% of patients, respectively. We found a correlation of T-cell abundance and the expression of TAAs and genes related to antigen presentation. TAA-specific T-cell responses were polyclonal, could be induced or enhanced using autologous CD40Bs and were cytotoxic in vitro. Despite the frequent expression of TAAs co-occurrence with immune responses was rare.

CONCLUSIONS

We identified the most relevant TAAs in EGA for monitoring of clinical trials and as therapeutic targets. Antigen-escape rather than missing immune response should be considered as mechanism underlying immunotherapy resistance of EGA.

Cellular plasticity and immune microenvironment of malignant pleural effusion are associated with EGFR-TKI resistance in non–small-cell lung carcinoma

Malignant pleural effusion (MPE) is a complication of lung cancer that can be used as an alternative method for tissue sampling because it is generally simple and minimally invasive. Our study evaluated the diagnostic potential of non–small-cell lung carcinoma (NSCLC)-associated MPE in terms of understanding tumor heterogeneity and identifying response factors for EGFR tyrosine kinase inhibitor (TKI) therapy. We performed a single-cell RNA sequencing analysis of 31,743 cells isolated from the MPEs of 9 patients with NSCLC (5 resistant and 4 sensitive to EGFR TKI) with EGFR mutations. Interestingly, lung epithelial precursor-like cells with upregulated GNB2L1 and CAV1 expression were enriched in the EGFR TKI-resistant group. Moreover, GZMK upregulated transitional effector T cells, and plasmacytoid dendritic cells were significantly enriched in the EGFR TKI-resistant patients. Our results suggest that cellular plasticity and immunosuppressive microenvironment in MPEs are potentially associated with the TKI response of patients with EGFR-mutated NSCLC.

•

ScRNA-seq reveals associations between cellular plasticity and EGFR-TKI response

•

Lung epithelial progenitor-like cells are abundant in the TKI-resistant group

•

HLA-II gene expression are upregulated in the epithelial cells of TKI-sensitive group

•

Immunosuppressive TME was associated with the TKI resistance in NSCLC

A maternal high-fat diet induces fetal origins of NASH-HCC in mice

Maternal overnutrition affects offspring susceptibility to nonalcoholic steatohepatitis (NASH). Male offspring from high-fat diet (HFD)-fed dams developed a severe form of NASH, leading to highly vascular tumor formation. The cancer/testis antigen HORMA domain containing protein 1 (HORMAD1), one of 146 upregulated differentially expressed genes in fetal livers from HFD-fed dams, was overexpressed with hypoxia-inducible factor 1 alpha (HIF-1alpha) in hepatoblasts and in NASH-based hepatocellular carcinoma (HCC) in offspring from HFD-fed dams at 15 weeks old. Hypoxia substantially increased Hormad1 expression in primary mouse hepatocytes. Despite the presence of three putative hypoxia response elements within the mouse Hormad1 gene, the Hif-1alpha siRNA only slightly decreased hypoxia-induced Hormad1 mRNA expression. In contrast, N-acetylcysteine, but not rotenone, inhibited hypoxia-induced Hormad1 expression, indicating its dependency on nonmitochondrial reactive oxygen species production. Synchrotron-based phase-contrast micro-CT of the fetuses from HFD-fed dams showed significant enlargement of the liver accompanied by a consistent size of the umbilical vein, which may cause hypoxia in the fetal liver. Based on these findings, a maternal HFD induces fetal origins of NASH/HCC via hypoxia, and HORMAD1 is a potential therapeutic target for NASH/HCC.

Leveraging epigenetics to enhance the efficacy of cancer-testis antigen: a potential candidate for immunotherapy

Ovarian cancer is the most lethal gynecological malignancy in women. The phenotype is characterized by delayed diagnosis, recurrence and drug resistance. Inherent immunogenicity potential, oncogenic function and expression of cancer-testis/germline antigen (CTA) in ovarian cancer render them a potential candidate for immunotherapy. Revolutionary clinical findings indicate that tumor antigen-mediated T-cell and dendritic cell-based immunotherapeutic approaches provide an excellent strategy for targeting tumors. Currently, dendritic cell vaccination for the treatment of B-cell lymphoma and CTA-based T-cell receptor transduced T-cell therapy involving MAGE-A4 and NY-ESO-1 are well documented and shown to be effective. This review highlighted the mechanical aspects of epigenetic drugs that can elicit a CTA-based humoral and cellular immune response and implicate T-cell and dendritic cell-based immunotherapeutic approaches.

Antigen-Specific TCR-T Cells for Acute Myeloid Leukemia: State of the Art and Challenges

The cytogenetic abnormalities and molecular mutations involved in acute myeloid leukemia (AML) lead to unique treatment challenges. Although adoptive T-cell therapies (ACT) such as chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the treatment of leukemias, especially B-cell malignancies, the optimal target surface antigen has yet to be discovered for AML. Alternatively, T-cell receptor (TCR)-redirected T cells can target intracellular antigens presented by HLA molecules, allowing the exploration of a broader territory of new therapeutic targets. Immunotherapy using adoptive transfer of WT1 antigen-specific TCR-T cells, for example, has had positive clinical successes in patients with AML. Nevertheless, AML can escape from immune system elimination by producing immunosuppressive factors or releasing several cytokines. This review presents recent advances of antigen-specific TCR-T cells in treating AML and discusses their challenges and future directions in clinical applications.

Meiotic Genes and DNA Double Strand Break Repair in Cancer

Tumor cells show widespread genetic alterations that change the expression of genes driving tumor progression, including genes that maintain genomic integrity. In recent years, it has become clear that tumors frequently reactivate genes whose expression is typically restricted to germ cells. As germ cells have specialized pathways to facilitate the exchange of genetic information between homologous chromosomes, their aberrant regulation influences how cancer cells repair DNA double strand breaks (DSB). This drives genomic instability and affects the response of tumor cells to anticancer therapies. Since meiotic genes are usually transcriptionally repressed in somatic cells of healthy tissues, targeting aberrantly expressed meiotic genes may provide a unique opportunity to specifically kill cancer cells whilst sparing the non-transformed somatic cells. In this review, we highlight meiotic genes that have been reported to affect DSB repair in cancers derived from somatic cells. A better understanding of their mechanistic role in the context of homology-directed DNA repair in somatic cancers may provide useful insights to find novel vulnerabilities that can be targeted.

Evolutionary Dynamics and Molecular Mechanisms of HORMA Domain Protein Signaling

Controlled assembly and disassembly of multi-protein complexes is central to cellular signaling. Proteins of the widespread and functionally diverse HORMA family nucleate assembly of signaling complexes by binding short peptide motifs through a distinctive safety-belt mechanism. HORMA proteins are now understood as key signaling proteins across kingdoms, serving as infection sensors in a bacterial immune system and playing central roles in eukaryotic cell cycle, genome stability, sexual reproduction, and cellular homeostasis pathways. Here, we describe how HORMA proteins' unique ability to adopt multiple conformational states underlies their functions in these diverse contexts. We also outline how a dedicated AAA+ ATPase regulator, Pch2/TRIP13, manipulates HORMA proteins' conformational states to activate or inactivate signaling in different cellular contexts. The emergence of Pch2/TRIP13 as a lynchpin for HORMA protein action in multiple genome-maintenance pathways accounts for its frequent misregulation in human cancers and highlights TRIP13 as a novel therapeutic target. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

mRNA-Based Cancer Vaccines: A Therapeutic Strategy for the Treatment of Melanoma Patients

Malignant melanoma is one of the most aggressive forms of cancer and the leading cause of death from skin tumors. Given the increased incidence of melanoma diagnoses in recent years, it is essential to develop effective treatments to control this disease. In this regard, the use of cancer vaccines to enhance cell-mediated immunity is considered to be one of the most modern immunotherapy options for cancer treatment. The most recent cancer vaccine options are mRNA vaccines, with a focus on their usage as modern treatments. Advantages of mRNA cancer vaccines include their rapid production and low manufacturing costs. mRNA-based vaccines are also able to induce both humoral and cellular immune responses. In addition to the many advantages of mRNA vaccines for the treatment of cancer, their use is associated with a number of challenges. For this reason, before mRNA vaccines can be used for the treatment of cancer, comprehensive information about them is required and a large number of trials need to be conducted. Here, we reviewed the general features of mRNA vaccines, including their basis, stabilization, and delivery methods. We also covered clinical trials involving the use of mRNA vaccines in melanoma cancer and the challenges involved with this type of treatment. This review also emphasized the combination of treatment with mRNA vaccines with the use of immune-checkpoint blockers to enhance cell-mediated immunity.

Cancer-Testis Antigens in Triple-Negative Breast Cancer: Role and Potential Utility in Clinical Practice

Breast cancer cells commonly express tumour-associated antigens that can induce immune responses to eradicate the tumour. Triple-negative breast cancer (TNBC) is a form of breast cancer lacking the expression of hormone receptors and cerbB2 (HER2) and tends to be more aggressive and associated with poorer prognoses due to the limited treatment options. Characterisation of biomarkers or treatment targets is thus of great significance in revealing additional therapeutic options. Cancer-testis antigens (CTAs) are tumour-associated antigens that have garnered strong attention as potential clinical biomarkers in targeted immunotherapy due to their cancer-restricted expressions and robust immunogenicity. Previous clinical studies reported that CTAs correlated with negative hormonal status, advanced tumour behaviour and a poor prognosis in a variety of cancers. Various studies also demonstrated the oncogenic potential of CTAs in cell proliferation by inhibiting cell death and inducing metastasis. Multiple clinical trials are in progress to evaluate the role of CTAs as treatment targets in various cancers. CTAs hold great promise as potential treatment targets and biomarkers in cancer, and further research could be conducted on elucidating the mechanism of actions of CTAs in breast cancer or combination therapy with other immune modulators. In the current review, we summarise the current understandings of CTAs in TNBC, addressing the role and utility of CTAs in TNBC, as well as discussing the potential applications and advantage of incorporating CTAs in clinical practise.

HORMAD1 promotes docetaxel resistance in triple negative breast cancer by enhancing DNA damage tolerance

HORMA domain‑containing protein 1 (HORMAD1), is normally expressed only in the germline, but is frequently re‑activated in human triple‑negative breast cancer (TNBC); however, its function in TNBC is largely unknown. In the present study, the expression and biological significance of HORMAD1 in human TNBC was evaluated. Bioinformatics analysis and reverse transcription‑quantitative PCR were used to evaluate HORMAD1 expression in datasets and cell lines. HORMAD1 protein expression was detected in TNBC samples using immunohistochemical assays, and the effect of HORMAD1 on cell proliferation was determined using Cell Counting Kit‑8, plate colony formation and standard growth curve assays. Cell cycle, reactive oxygen species (ROS) and apoptosis analyses were conducted using flow cytometry. The activity of caspases was measured using caspase activity assay kit. The levels of key apoptosis regulators and autophagy markers were detected by western blot analysis. TNBC cell survival and apoptosis were not influenced by small interfering RNA targeting HORMAD1 alone; however, HORMAD1 knockdown enhanced autophagy and docetaxel (Doc)‑induced apoptosis, compared with the control group. Furthermore, higher ROS levels and caspase‑3, ‑8 and ‑9 activity were detected in MDA‑MB‑436 TNBC cells with HORMAD1 knockdown upon exposure to Doc. The levels of the induced DNA damage marker γH2AX were also higher, while those of the DNA repair protein RAD51 were lower in TNBC cells with HORMAD1 knockdown compared with the controls. Furthermore, the expression of the autophagy marker P62 was enhanced in MDA‑MB‑231 cells in response to HORMAD1 overexpression. Notably, Doc‑induced apoptosis was similarly increased by both HORMAD1 overexpression and treatment with the autophagy inhibitor, 3‑methyladenine (3MA); however, the Doc‑induced increase in autophagy was not inhibited by 3MA. The present data indicated that HORMAD1 was involved in autophagy and that the inhibition of autophagy can partially enhance the induction of apoptosis by Doc. The role of HORMAD1 in the DNA damage tolerance of tumor cells may be the main reason for Doc resistance; hence, HORMAD1 could be an important therapeutic target in TNBC.

Multiomics analysis reveals CT83 is the most specific gene for triple negative breast cancer and its hypomethylation is oncogenic in breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer (BrC) subtype lacking effective therapeutic targets currently. The development of multi-omics databases facilities the identification of core genes for TNBC. Using TCGA-BRCA and METABRIC datasets, we identified CT83 as the most TNBC-specific gene. By further integrating FUSCC-TNBC, CCLE, TCGA pan-cancer, Expression Atlas, and Human Protein Atlas datasets, we found CT83 is frequently activated in TNBC and many other cancers, while it is always silenced in non-TNBC, 120 types of normal non-testis tissues, and 18 types of blood cells. Notably, according to the TCGA-BRCA methylation data, hypomethylation on chromosome X 116,463,019 to 116,463,039 is significantly correlated with the abnormal activation of CT83 in BrC. Using Kaplan-Meier Plotter, we demonstrated that activated CT83 is significantly associated with unfavorably overall survival in BrC and worse outcomes in some other cancers. Furthermore, GSEA suggested that the abnormal activation of CT83 in BrC is probably oncogenic by triggering the activation of cell cycle signaling. Meanwhile, we also noticed copy number variations and mutations of CT83 are quite rare in any cancer type, and its role in immune infiltration is not significant. In summary, we highlighted the significance of CT83 for TNBC and presented a comprehensive bioinformatics strategy for single-gene analysis in cancer.

Immunohistochemical Detection of Cancer-Testis Antigen PRAME

Cancer-testis (CT) antigens were identified by their ability to elicit T- or B-cell immune responses in the autologous host. They are typically expressed in a wide variety of neoplasms and in normal adult tissues are restricted to testicular germ cells. PReferentially expressed Antigen of Melanoma (PRAME) is a member of the family of nonclassical CT antigens being expressed in a few other normal tissues besides testis. Interestingly, knowledge about the protein expression of many CT antigens is still incomplete due to the limited availability of reagents for their immunohistochemical detection. Here, we tested several commercially available serological reagents and identified a monoclonal antibody suitable for the immunohistochemical detection of PRAME in formalin-fixed paraffin-embedded specimens. We also tested a wide array of normal and neoplastic tissues. PRAME protein expression in normal tissues is congruent with original molecular data being present in the testis, and at low levels in the endometrium, adrenal cortex, and adult as well as fetal ovary. In tumors, there is diffuse PRAME immunoreactivity in most metastatic melanomas, myxoid liposarcomas, and synovial sarcomas. Other neoplasms such as seminomas and carcinomas of various origins including endometrial, serous ovarian, mammary ductal, lung, and renal showed an intermediate proportion of cases and variable extent of tumor cells positive for PRAME protein expression. As seen with other CT antigens, hepatocellular and colorectal carcinoma, Leydig cell tumors, mesothelioma, and leiomyosarcoma are poor expressers of PRAME.

Transcriptome integration analysis and specific diagnosis model construction for Hodgkin's lymphoma, diffuse large B-cell lymphoma, and mantle cell lymphoma

Transcriptome differences between Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL), which are all derived from B cell, remained unclear. This study aimed to construct lymphoma-specific diagnostic models by screening lymphoma marker genes. Transcriptome data of HL, DLBCL, and MCL were obtained from public databases. Lymphoma marker genes were screened by comparing cases and controls as well as the intergroup differences among lymphomas. A total of 9 HL marker genes, 7 DLBCL marker genes, and 4 MCL marker genes were screened in this study. Most HL marker genes were upregulated, whereas DLBCL and MCL marker genes were downregulated compared to controls. The optimal HL-specific diagnostic model contains one marker gene (MYH2) with an AUC of 0.901. The optimal DLBCL-specific diagnostic model contains 7 marker genes (LIPF, CCDC144B, PRO2964, PHF1, SFTPA2, NTS, and HP) with an AUC of 0.951. The optimal MCL-specific diagnostic model contains 3 marker genes (IGLV3-19, IGKV4-1, and PRB3) with an AUC of 0.843. The present study reveals the transcriptome data-based differences between HL, DLBCL, and MCL, when combined with other clinical markers, may help the clinical diagnosis and prognosis.

Actin-Like Protein 8 Promotes the Progression of Triple-Negative Breast Cancer via Activating PI3K/AKT/mTOR Pathway

Objective

The purpose of this study was to investigate the function of actin-like protein 8 (ACTL8) on triple-negative breast cancer (TNBC) and its potential mechanisms.

Methods

In our study, ACTL8 expression and the prognostic values of ACTL8 were evaluated via the dataset from the Cancer Genome Atlas (TCGA). At the same time, the expression of ACTL8 in TNBC cells was measured by Western blot and qRT-PCR. Then, the effects of ACTL8 on the growth and metastasis of TNBC were investigated by using 5-ethynyl-20-deoxyuridine (EdU), colony formation, flow cytometry, wound healing and transwell assays. Mechanistically, Western blot was performed to confirm the interaction between ACTL8 and phosphatidylinositol 3′-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway in TNBC.

Results

ACTL8 expression was upregulated in TNBC and associated with the poor prognosis of TNBC. Silencing ACTL8 suppressed the proliferation, migration and invasion, also promoted the apoptosis in MDA-MB-231 and BT-549 cells. Moreover, we found that silencing ACTL8 could inhibit the activation of PI3K/AKT/mTOR signaling pathway in MDA-MB-231 and BT-549 cells. Meanwhile, the impact of silencing ACTL8 on the proliferation, apoptosis, migration and invasion was enhanced by PI3K/AKT/mTOR pathway inhibitor (Wortmannin) and reversed by PI3K/AKT/mTOR pathway activator (740Y-P).

Conclusion

Our data demonstrated that ACTL8 may facilitate the proliferation, migration and invasion, while inhibiting apoptosis through activating PI3K/Akt/mTOR signaling pathway in TNBC.

Cancer Vaccines: Antigen Selection Strategy

Unlike traditional cancer therapies, cancer vaccines (CVs) harness a high specificity of the host’s immunity to kill tumor cells. CVs can train and bolster the patient’s immune system to recognize and eliminate malignant cells by enhancing immune cells’ identification of antigens expressed on cancer cells. Various features of antigens like immunogenicity and avidity influence the efficacy of CVs. Therefore, the choice and application of antigens play a critical role in establishing and developing CVs. Tumor-associated antigens (TAAs), a group of proteins expressed at elevated levels in tumor cells but lower levels in healthy normal cells, have been well-studied and developed in CVs. However, immunological tolerance, HLA restriction, and adverse events are major obstacles that threaten TAA-based CVs’ efficacy due to the “self-protein” characteristic of TAAs. As “abnormal proteins” that are completely absent from normal cells, tumor-specific antigens (TSAs) can trigger a robust immune response against tumor cells with high specificity and without going through central tolerance, contributing to cancer vaccine development feasibility. In this review, we focus on the unique features of TAAs and TSAs and their application in vaccines, summarizing their performance in preclinical and clinical trials.

Combined RNA/tissue profiling identifies novel Cancer/testis genes

Cancer/Testis (CT) genes are induced in germ cells, repressed in somatic cells, and derepressed in somatic tumors, where these genes can contribute to cancer progression. CT gene identification requires data obtained using standardized protocols and technologies. This is a challenge because data for germ cells, gonads, normal somatic tissues, and a wide range of cancer samples stem from multiple sources and were generated over substantial periods of time. We carried out a GeneChip‐based RNA profiling analysis using our own data for testis and enriched germ cells, data for somatic cancers from the Expression Project for Oncology, and data for normal somatic tissues from the Gene Omnibus Repository. We identified 478 candidate loci that include known CT genes, numerous genes associated with oncogenic processes, and novel candidates that are not referenced in the Cancer/Testis Database (www.cta.lncc.br). We complemented RNA expression data at the protein level for SPESP1, GALNTL5, PDCL2, and C11orf42 using cancer tissue microarrays covering malignant tumors of breast, uterus, thyroid, and kidney, as well as published RNA profiling and immunohistochemical data provided by the Human Protein Atlas (www.proteinatlas.org). We report that combined RNA/tissue profiling identifies novel CT genes that may be of clinical interest as therapeutical targets or biomarkers. Our findings also highlight the challenges of detecting truly germ cell‐specific mRNAs and the proteins they encode in highly heterogenous testicular, somatic, and tumor tissues.

Does EIF2S3 Retrogene Activation Regulate Cancer/Testis Antigen Expression in Human Cancers?

Cancer/Testis (C/T) antigens are a group of antigens, expressed in almost all types of cancers, which can elicit an immune response in patients whose cancers express these antigens. They are currently of great interest as targets for the development of cancer biomarkers and the creation of immunotherapies that directly target tumors in patients. Currently there are 280 C/T antigens and their variants listed on the C/T antigen data base. All known C/T antigens are encoded for by genes which are normally only expressed in the male testis; specifically during the process of spermatogenesis. They are therefore only expressed in germ cells that are in the process of differentiating into sperm. Expression of C/T antigens in tumors is thus a biological anomaly as, with the exception of germ cell tumors, cancers arise from somatic tissues which are not known to express any of the genes specifically involved in spermatogenesis. How and why C/T antigens are expressed in tumors remains an enigma. In this paper we present a hypothesis which proposes a mechanism for the activation of C/T antigen encoding genes in tumors. We propose that aberrant activation of the human autosomal retrogene, EIF2S3B, which regulates initiation and maintenance of spermatogenesis in males, is responsible for C/T expression. Because both male and females have tumors that express C/T antigens activation of spermatogenesis genes in tumors must involve a non-sex specific pathway. This can be explained by the copy number of EIF2S3 genes uniquely present within the human genome.

Expression profile of ACTL8, CTCFL, OIP5 and XAGE3 in glioma and their prognostic significance: a retrospective clinical study

Cancer/testis antigens (CTAs) are attractive therapeutic targets for tumor immunotherapy due to their restrictive expression in normal testis but excessive in majority of tumor types. ACTL8, CTCFL, OIP5 and XAGE3 are members of the CTAs family. Currently, the data of ACTL8, CTCFL, OIP5 and XAGE3 expression in glioma is limited. Methods: ACTL8, CTCFL, OIP5 and XAGE3 mRAN and protein expressions were detected in 108 glioma samples by Reverse Transcriptase-PCR (RT-PCR) and immunohistochemistry and the correlations between their expressions and clinical indexes were analyzed. Furthermore, their clinical significance on glioma prognosis was determined by follow-up data. Results: The mRNA positive rate of ACTL8, CTCFL, OIP5 and XAGE3 was 15.74% (17/108), 22.22% (24/108), 13.89% (15/108) and 37.96% (41/108), respectively. At least one CTA mRNA was expressed by 61.11% of glioma tissues, while 2 or more by 29.63%. For protein expression, the positive rate of them was 21.30% (23/108), 34.26% (37/108), 19.44% (21/108) and 23.15% (25/108), respectively. At least one CTA protein was expressed by 58.33% of glioma tissues and 2 or more by 29.63%. Although there were no correlations between their mRNA expressions and clinicopathological parameters, the protein expression of ACTL8, OIP5 and XAGE3 was positively correlated with KPS; while the ACTL8 protein was correlated with gender, and OIP5 protein with gender and WHO grade. Kaplan-Meier analysis revealed a significant negative correlation between the CTCFL protein expression, combined ACTL8 and/or CTCFL protein expression and survival. Conclusions: The results suggest that the cohort of glioma does express ACTL8, CTCFL, OIP5 and XAGE3 at both mRNA and protein levels indicating glioma is CTAs-rich tumors. CTCFL protein and the combined ACTL8 and/or CTCFL protein might act as poor prognostic markers for glioma and as potential ideal combined antigens for glioma immunotherapy.

The expression, modulation and use of cancer-testis antigens as potential biomarkers for cancer immunotherapy

Cancer-testis antigens (CTA) are tumor antigens, present in the germ cells of testes, ovaries and trophoblasts, which undergo deregulated expression in the tumor and malignant cells. CTA genes are either X-linked or autosomal, favourably expressed in spermatogonia and spermatocytes, respectively. CTAs trigger unprompted humoral immunity and immune responses in malignancies, altering tumor cell physiology and neoplastic behaviors. CTAs demonstrate varied expression profile, with increased abundance in malignant melanoma and prostate, lung, breast and epithelial cell cancers, and a relatively reduced prevalence in intestinal cancer, renal cell adenocarcinoma and malignancies of immune cells. A combination of epigenetic and non-epigenetic agents regulates CTA mRNA expression, with the key participation of CpG islands and CpG-rich promoters, histone methyltransferases, cytokines, tyrosine kinases and transcriptional activators and repressors. CTA triggers gametogenesis, in association with mutated tumorigenic genes and tumor repressors. The CTAs function as potential biomarkers, particularly for prostate, cervical, breast, colorectal, gastric, urinary bladder, liver and lung carcinomas, characterized by alternate splicing and phenotypic heterogeneity in the cells. Additionally, CTAs are prospective targets for vaccine therapy, with the MAGE-A3 and NYESO-1 undergoing clinical trials for tumor regression in malignant melanoma. They have been deemed important for adaptive immunotherapy, marked by limited expression in normal somatic tissues and recurrent up-regulation in epithelial carcinoma. Overall, the current review delineates an up-dated understanding of the intricate processes of CTA expression and regulation in cancer. It further portrays the role of CTAs as biomarkers and probable candidates for tumor immunotherapy, with a future prospect in cancer treatment.

Context-Dependent Tumorigenic Effect of Testis-Specific Mitochondrial Protein Tiny Tim 2 in Drosophila Somatic Epithelia

We have undertaken a study towards understanding the effect of ectopic expression of testis proteins in the soma in Drosophila. Here, we show that in the larval neuroepithelium, ectopic expression of the germline-specific component of the inner mitochondrial translocation complex tiny tim 2 (ttm2) brings about cell autonomous hyperplasia and extension of G2 phase. In the wing discs, cells expressing ectopic ttm2 upregulate Jun N-terminal kinase (JNK) signaling, present extended G2, become invasive, and elicit non-cell autonomous G2 extension and overgrowth of the wild-type neighboring tissue. Ectopic tomboy20, a germline-specific member of the outer mitochondrial translocation complex is also tumorigenic in wing discs. Our results demonstrate the tumorigenic potential of unscheduled expression of these two testis proteins in the soma. They also show that a unique tumorigenic event may trigger different tumor growth pathways depending on the tissular context.

Cancer-Testis Gene Expression in Hepatocellular Carcinoma: Identification of Prognostic Markers and Potential Targets for Immunotherapy

BACKGROUND

Cancer-testis genes can serve as prognostic biomarkers and valuable targets for immunotherapy in multiple tumors because of their restricted expression in testis and cancer. However, their expression pattern in hepatocellular carcinoma is still not well understood. The purpose is to comprehensively characterize the cancer-testis gene expression in hepatocellular carcinoma as well as identify prognostic markers and potential targets for immunotherapy.

METHODS

Cancer-testis database and publicly available data sets reporting new cancer-testis genes were integrated, and then restricted them in a testis and hepatocellular carcinoma expression pattern. Pathway enrichment analysis and survival analysis were conducted to evaluate the biological function and prognostic effect of cancer-testis genes. Clustering analysis and coexpression analysis were performed to illustrate cancer-testis gene expression patterns in hepatocellular carcinoma. The association of gene expression of each cancer-testis gene to the corresponding methylation status was detected. Finally, we explored the associations between cancer-testis genes and CD8⁺ T-cell infiltration in hepatocellular carcinoma by TISIDB, and then validated it in an independent hepatocellular carcinoma cohort with 72 patients.

RESULTS

A total of 59 testis-specific genes were identified highly expressed in hepatocellular carcinoma. Pathway enrichment analysis revealed that cancer-testis genes in hepatocellular carcinoma significantly involves in the process of cell cycle regulation. Most of the cancer-testis genes were coexpressed, and cluster analysis suggested that cancer-testis gene expressed in hepatocellular carcinoma is independent of sex, hepatitis status, and histology type. We also found that demethylation might be a regulatory mechanism of cancer-testis gene expression in hepatocellular carcinoma. Survival analysis indicated that cancer-testis genes could predict the prognosis of patients with hepatocellular carcinoma. Furthermore, BUB1B was identified contributing to the resistance of CD8⁺ T-cell infiltration in hepatocellular carcinoma and was an independent prognostic factor both for overall survival and disease-free survival.

CONCLUSIONS

Our analysis enables better understanding of cancer-testis genes in hepatocellular carcinoma and provides potential targets for hepatocellular carcinoma treatment. Experimental and clinical studies are needed for further validations.

Aberrantly expressed HORMAD1 disrupts nuclear localization of MCM8-MCM9 complex and compromises DNA mismatch repair in cancer cells

HORMAD1 is a meiosis-specific protein that promotes synapsis and recombination of homologous chromosomes in meiotic prophase. Originally identified as a cancer/testis antigen, HORMAD1 is also aberrantly expressed in several cancers. However, the functions of HORMAD1 in cancer cells are still not clear. Here, we show that HORMAD1 is aberrantly expressed in a wide variety of cancers and compromises DNA mismatch repair in cancer cells. Mechanistically, HORMAD1 interacts with MCM8–MCM9 complex and prevents its efficient nuclear localization. As a consequence, HORMAD1-expressing cancer cells have reduced MLH1 chromatin binding and DNA mismatch repair defects. Consistently, HORMAD1 expression is associated with increased mutation load and genomic instability in many cancers. Taken together, our study provides mechanistic insights into HORMAD1’s functions in cancer cells, which can potentially be exploited for targeted therapy of HORMAD1-expressing cancers.

Intra-Cluster Distance Minimization in DNA Methylation Analysis Using an Advanced Tabu-Based Iterative k-Medoids Clustering Algorithm (T-CLUST)

Recent advances in DNA methylation profiling have paved the way for understanding the underlying epigenetic mechanisms of various diseases such as cancer. While conventional distance-based clustering algorithms (e.g., hierarchical and k-means clustering) have been heavily used in such profiling owing to their speed in conduct of high-throughput analysis, these methods commonly converge to suboptimal solutions and/or trivial clusters due to their greedy search nature. Hence, methodologies are needed to improve the quality of clusters formed by these algorithms without sacrificing from their speed. In this study, we introduce three related algorithms for a complete high-throughput methylation analysis: a variance-based dimension reduction algorithm to handle high-dimensionality in data, an outlier detection algorithm to identify the outliers of data, and an advanced Tabu-based iterative k-medoids clustering algorithm (T-CLUST) to reduce the impact of initial solutions on the performance of conventional k-medoids algorithm. The performance of the proposed algorithms is demonstrated on nine different real DNA methylation datasets obtained from the Gene Expression Omnibus DataSets database. The accuracy of the cluster identification obtained by our proposed algorithms is higher than those of hierarchical and k-means clustering, as well as the conventional methods. The algorithms are implemented in MATLAB, and available at: http://www.coe.miami.edu/simlab/tclust.html.

A 17-gene expression-based prognostic signature associated with the prognosis of patients with breast cancer: A STROBE-compliant study

Identification of reliable predictive biomarkers for patients with breast cancer (BC).Univariate Cox proportional hazards regression model was conducted to identify genes correlated with the overall survival (OS) of patients in the TCGA-BRCA cohort. Functional enrichment analysis was conducted to investigate the biological meaning of these survival related genes. Then, patients in TCGA-BCRA were randomly divided into training set and test. Least absolute shrinkage and selection operator (LASSO) penalized Cox regression model was performed and the risk score of BC patients in this model was used to build a prognostic signature. The prognostic performance of the signature was evaluated in the training set, test set, and an independent validation set GSE7390.2519 genes were demonstrated to be significantly associated with the OS of BC patients. Functional annotation of the 2519 genes suggested that these genes were associated with immune response and protein synthesis related gene ontology terms and pathways. 17 genes were identified in the LASSO Cox regression model and used to construct a 17-gene signature. Patients in the 17-gene signature low risk group have better OS and event-free survival compared with those in the 17-gene signature high risk group in the TCGA-BRCA cohort. The prognostic role of the 17-gene signature has been confirmed in the validation cohort. Multivariable Cox proportional hazards regression model suggested the 17-gene signature was an independent prognostic factor in BC.The 17-gene signature we developed could successfully classify patients into high- and low-risk groups, indicating that it might serve as candidate biomarker in BC.

The ectopic expression of meiCT genes promotes meiomitosis and may facilitate carcinogenesis

Cancer meiomitosis is defined as the concurrent activation of both mitotic and meiotic machineries in neoplastic cells that confer a selective advantage together with increased genomic instability. MeiCT (meiosis-specific cancer/testis) genes that perform specialized functions in the germline events required for the first meiotic division are ectopically expressed in several cancers. Here we describe the expression profiles of meiCT genes and proteins across a number of cancers and review the proposed mechanisms that increase aneuploidy and elicit reduction division in polyploid cells. These mechanisms are centered on the overexpression and function of meiCT proteins in cancers under various conditions that includes a response to genotoxic stress. Since meiCT genes are transcriptionally repressed in somatic cells, their target offers a promising therapeutic approach with limited toxicity to healthy tissues. Throughout the review, we provide a detailed description of the roles for each gene in the context of meiosis and we discuss proposed functions and outcomes resulting from their ectopic reactivation in cancer.

Actin‑like protein 8 executes a promoting function in the malignant progression of endometrial cancer: identification of a promising biomarker

Endometrial cancer (EC) is generally considered as a disease that affects older women. We attempt to explore the role of actin‑like protein 8 (ACTL8) in EC and how it achieves its function. Based on the data from The Cancer Genome Atlas (TCGA), we found that ACTL8 expression was up-regulated in EC tissues and correlated with shorter overall survival of EC patients. ACTL8 expression was significantly associated with age, clinical-stage, or grade. Cox proportional hazards model analysis revealed that ACTL8 expression, grade, and clinical-stage were promising independent prognostic factors of EC. Knockdown of ACTL8 repressed the proliferative, migrating and invading capabilities of human EC cell lines KLE and Ishikawa. Silencing ACTL8 up-regulated the negative cell cycle regulator p21 and epithelial marker E-cadherin, and down-regulated the positive cell cycle regulator Cyclin A, mesenchymal markers MMP-9 and N-cadherin in KLE cells. Collectively, these outcomes illustrated that ACTL8 might act as a tumor facilitator during EC progression.

Cancer/testis antigens expression during cultivation of melanoma and soft tissue sarcoma cells

BACKGROUND

Autologous dendritic cells (DC) loaded with tumor-associated antigens (TAAs) are a promising approach for anticancer immunotherapy. Polyantigen lysates appear to be an excellent source of TAAs for loading onto the patient's dendritic cells. Cancer/testis antigens (CTA) are expressed by a wide range of tumors, but are minimally expressed on normal tissues, and could serve as a universal target for immunotherapy. However, CTA expression levels can vary significantly in patients with the same tumor type. We proposed that patients who do not respond to DC-based therapy may have distinct features of the CTA expression profile on tumor cells.

PATIENTS AND METHODS

We compared the gene expression of the principal families CTA in 22 melanoma and 27 soft tissue and bone sarcomas cell lines (STBS), received from patients and used for DC vaccine preparation.

RESULTS

The majority (47 of 49, 95.9%) cell lines showed CTA gene activity. The incidence of gene expression of GAGE, NYESO1, MAGEA1, PRAME's was significantly different (adj. p < 0.05) between melanoma and sarcoma cell lines. The expression of the SCP1 gene was detected neither in melanoma cells nor in the STBS cells. Clustering by the gene expression profile revealed four different expression patterns. We found three main patterns types: hyperexpression of multiple CTA, hyperexpression of one CTA with almost no expression of others, and no expression of CTA. All clusters types exist in melanoma and sarcoma cell lines. We observed dependence of killing efficacy from the PRAME (rho = 0.940, adj. p < 0.01) expression during real-time monitoring with the xCELLigence system of the interaction between melanoma or sarcoma cells with the T-lymphocytes activated by the lysate of selected allogenous melanoma cell lines with high expression of CTA.

CONCLUSION

Our results demonstrate that one can use lysates from allogeneic melanoma cell lines as a source of CTA for DC load during the production of anticancer vaccines for the STBS treatment. Patterns of CTA expression should be evaluated as biomarkers of response in prospective clinical trials.

Actin-like protein 8 promotes cell proliferation, colony-formation, proangiogenesis, migration and invasion in lung adenocarcinoma cells

Background

Non‐small cell lung cancer (NSCLC) is the leading cause of cancer‐associated mortality worldwide of which lung adenocarcinoma (LUAD) is the most common. The identification of oncogenes and effective drug targets is the key to individualized LUAD treatment. Actin‐like protein 8 (ACTL8), a member of the cancer/testis antigen family, is associated with tumor growth and patient prognosis in various types of cancer. However, whether ACTL8 is involved in the development of LUAD remains unknown. The aim of the present study was to demonstrate the role of ACTL8 in human LUAD cells.

Methods

The expression of ACTL8 in LUAD tissues and cell lines was assessed using immunohistochemistry and western blotting. Additionally, plasmids expressing ACTL8‐specific short hairpin RNAs were used to generate lentiviruses which were subsequently used to infect A549 and NCI‐H1975 human LUAD cells. Cell proliferation, migration, invasion and apoptosis, as well as cell cycle progression and the expression of protein markers of epithelial to mesenchymal transition were investigated. A549 cell tumor growth in nude mice was also examined.

Results

The results showed that ACTL8 was highly expressed in A549 and NCI‐H1975 LUAD cell lines. Additionally, ACTL8‐knockdown inhibited proliferation, colony formation, cell cycle progression, migration and invasion, and increased apoptosis in both cell lines. Furthermore, in vivo experiments in nude mice revealed that ACTL8‐knockdown inhibited A549 cell tumor growth.

Conclusion

These results suggest that ACTL8 serves an oncogenic role in human LUAD cells, and that ACTL8 may represent a potential therapeutic target for LUAD.

Key points

Our results suggest that ACTL8 serves an oncogenic role in human LUAD cells, and that ACTL8 may represent a potential therapeutic target for LUAD.

Differential Expression of ACTL8 Gene and Association Study of Its Variations with Growth Traits in Chinese Cattle

Simple Summary

Marker-assisted selection has a great influence on livestock molecular breeding development. The discovery of key molecular markers that are significantly associated with body size data will accelerate molecular breeding in livestock. In this study, the cattle ACTL8 gene is a critical candidate gene. It was found that there are multiple mutations in the ACTL8 gene that may be used as molecular markers. Our results have shown that the mutations of the ACTL8 gene could have important reference value in molecular breeding for beef cattle.

Abstract

Mutations are heritable changes at the base level of genomic DNA. Furthermore, mutations lead to genetic polymorphisms and may alter animal growth phenotypes. Our previous study found that mutations in the bovine Actin-like protein 8 (ACTL8) gene may be involved in muscle growth and development. This study explored several mutations of the ACTL8 gene and their influence on body size in Chinese beef cattle, as well as tested the tissue expression profile of the ACTL8 gene in Qinchuan cattle at different ages. Five single nucleotide polymorphisms (SNPs) (including one synonymous mutation (c.2135552895G > A)) and two insertion/deletion polymorphisms (indels) were identified in the ACTL8 gene from 1138 cattle by DNA-seq, RFLP and other methods. Then, the expression profile of the ACTL8 gene in Qinchuan cattle showed that it was expressed in heart, spleen, lung, liver, muscle, and fat tissues. Moreover, the expression level of ACTL8 was increased with cattle growth (p < 0.01). The ACTL8 mRNA expression level in kidney and muscle tissues was the highest in the calves, while lowest in the fetal stage. Overall, we showed that the mutations could act as markers in beef molecular breeding and selection of the growth traits of cattle.

Screening and identification of biomarkers associated with clinicopathological parameters and prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a major type of malignant tumor of the oral cavity. Despite marked advances in the management and diagnosis of OSCC, the associated overall survival ratio has only exhibited a modest increase in recent years. The present study aimed to identify potential crucial genes associated with clinical features and prognosis for OSCC, and to provide a basis for further investigation. RNA-sequencing data and corresponding clinical information were downloaded from The Cancer Genome Atlas database and differentially expressed mRNAs (DEmRNAs) were identified using the edgeR package. Bioinformatics analysis was performed to identify differentially expressed clinical features-associated mRNAs (CFmRNAs) and enhance the current knowledge of the function of them. Functional enrichment analysis and protein-protein interplay (PPI) network analysis were then performed to better understand CFmRNAs. Survival-associated genes were analyzed with Kaplan-Meier survival curves and the log-rank test. A total of 2,013 DEmRNAs between OSCC samples and normal tissues were identified, 180 of which were associated with clinical features. A total of 17 GO terms and 4 KEGG pathways were significantly enriched in functional enrichment analysis. A total of 4 hub genes (albumin, statherin, neurotensin and mucin 7) were identified in the PPI network analysis. A total of 6 genes (DDB1 and CUL4 associated factor 4 like 2, opiorphin prepropeptide, R3H domain containing like, transmembrane phosphatase with tensin homology, actin like 8 and protocadherin α 11) were observed to have an influence on survival. The DEmRNAs identified may have a crucial role in the genesis and development of OSCC and may be further developed for diagnostic, therapeutic and prognostic applications for OSCC in the future.

Identification of cancer/testis antigen 2 gene as a potential hepatocellular carcinoma therapeutic target by hub gene screening with topological analysis

The 5-year survival rate of hepatocellular carcinoma (HCC) is <20%; thus, identifying new potential therapeutic targets or novel biomarkers for prognosis prediction is crucial. The present study aimed to screen hub genes by constructing protein-protein interaction (PPI) subnetworks using topological analysis methods, as well as reveal their clinical significance through big data analytics and their association with the clinicopathological features. Firstly, the PPI subnetworks were constructed using four topological analysis methods, including the MCC, DMNC, MNC and degree methods, to obtain 6 hub genes. Subsequently, the hub gene cancer/testis antigen 2 (CTAG2), which affects the prognosis of HCC (overall survival, P=0.035), was acquired by analysing clinical data in The Cancer Genome Atlas database. Meanwhile, CTAG2 expression was significantly associated with the age at diagnosis (P=0.003), T stage (P=0.028), TNM stage (P=0.028) and α-fetoprotein (AFP) expression (P=0.045). Further immunohistochemical analysis of samples collected in our hospital revealed that the expression level of CTAG2 in 46 HCC tissues was significantly higher in comparison with that in paired adjacent tissues. The clinical data indicated that the expression of CTAG2 was significantly correlated with the hepatitis B virus status (P=0.010) and AFP expression (P=0.004). These results were then found to be consistent with the results of big data analytics. Furthermore, Gene Set Enrichment Analysis demonstrated that the function of CTAG2 in HCC may be associated with the cell cycle. Taken together, these findings suggest that CTAG2 may serve as a new potential therapeutic target for HCC patients.

Systematic cancer-testis gene expression analysis identified CDCA5 as a potential therapeutic target in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies with poor prognosis. Cancer-testis genes (CTGs) have been vigorously pursued as targets for cancer immunotherapy, but the expressive patterns and functional roles of CTGs remain unclear in ESCC.

METHODS

A systematic screening strategy was adopted to screen CTGs in ESCC by integrating multiple public databases and RNA expression microarray data from 119 ESCC subjects. For the newly identified ESCC prognosis-associated CTGs, an independent cohort of 118 patients with ESCC was recruited to validate the relationship via immunohistochemistry. Furthermore, functional assays were performed to determine the underlying mechanisms.

FINDINGS

21 genes were recognized as CTGs, in particular, CDCA5 was aberrantly upregulated in ESCC tissues and significantly associated with poor prognosis (HR = 1.85, 95%CI: 1.14-3.01, P = .013). Immunohistochemical staining confirmed that positive CDCA5 expression was associated with advanced TNM staging and a shorter overall survival rate (45.59% vs 28.00% for CDCA5-/+ subjects, P = 1.86 × 10-3). H3K27 acetylation in CDCA5 promoter might lead to the activation of CDCA5 during ESCC tumorigenesis. Functionally, in vitro assay of gain- and loss-of-function of CDCA5 suggested that CDCA5 could promote ESCC cells proliferation, invasion, migration, apoptosis resistance and reduce chemosensitivity to cisplatin. Moreover, in vivo assay showed that silenced CDCA5 could inhibit tumor growth. Mechanistically, CDCA5 knockdown led to an arrest in G2/M phase and changes in the expression of factors that played fundamental roles in the cell cycle pathway.

INTERPRETATION

CDCA5 contributed to ESCC progression and might serve as an attractive target for ESCC immunotherapy. FUND: This work was supported by the Natural Science Foundation of Jiangsu Province (No. BK20181083 and BK20181496), Jiangsu Top Expert Program in Six Professions (No. WSW-003 and WSW-007), Major Program of Science and Technology Foundation of Jiangsu Province (No. BE2016790 and BE2018746), Jiangsu Medical Young Talent Project (No. QNRC2016566), the Program of Jiangsu Medical Innovation Team (No. CXTDA2017006), Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX18_1487) and Jiangsu Province 333 Talents Project (No. BRA2017545).

Expression of cancer/testis antigens in cutaneous melanoma: a systematic review

The cancer/testis antigen (CTA) family is a group of antigens whose expression is restricted to male germline cells of the testis and various malignancies. This expression pattern makes this group of antigens potential targets for immunotherapy. The aim of this study was to create an overview of CTA expressed by melanoma cells at mRNA and protein level. A systematic literature search was performed in Medline (PubMed) and Embase from inception up to and including February 2018. Studies were screened for eligibility by two independent reviewers. A total of 65 full-text articles were included in the final analysis. A total of 48 CTA have been studied in melanoma. Various CTA show different expression rates in primary and metastatic tumours. Of the 48 CTA, the most studied were MAGE-A3, MAGE-A1, NY-ESO-1, MAGE-A4, SSX2, MAGE-A2, MAGE-C1/CT7, SSX1, MAGE-C2/CT10 and MAGE-A12. On average, MAGE-A3 mRNA is present in 36% of primary tumours, whereas metastatic tumours have an expression rate of 55-81%. The same applies to the protein expression rate of MAGE-A3 in primary tumours, which is reported to be at 15-37%, whereas metastatic tumours have a higher expression rate of 25-70%. This trend of increased expression in metastases compared with primary tumours is observed with MAGE-A1, MAGE-A2, MAGE-A4, MAGE-A12 and NY-ESO-1. Many CTA are expressed on melanoma. This review provides an overview of the expression frequency of CTAs in melanoma and may aid in identifying CTA as the therapeutic target for immunotherapy.

Cancer Testis Antigens and Immunotherapy: Where Do We Stand in the Targeting of PRAME?

PRAME or PReferentially expressed Antigen in Melanoma is a testis-selective cancer testis antigen (CTA) with restricted expression in somatic tissues and re-expression in various cancers. It is one of the most widely studied CTAs and has been associated with the outcome and risk of metastasis. Although little is known about its pathophysiological function, PRAME has gained interest as a candidate target for immunotherapy. This review provides an update on our knowledge on PRAME expression and function in healthy and malignant cells and the current immunotherapeutic strategies targeting PRAME with their specific challenges and opportunities. We also highlight some of the features that position PRAME as a unique cancer testis antigen to target.