Elevated PRAME expression: what does this mean for treatment of head and neck squamous cell carcinoma?

T-cell receptor-based therapy: an innovative therapeutic approach for solid tumors

T-cell receptor (TCR)-based adoptive therapy employs genetically modified lymphocytes that are directed against specific tumor markers. This therapeutic modality requires a structured and integrated process that involves patient screening (e.g., for HLA-A*02:01 and specific tumor targets), leukapheresis, generation of transduced TCR product, lymphodepletion, and infusion of the TCR-based adoptive therapy. In this review, we summarize the current technology and early clinical development of TCR-based therapy in patients with solid tumors. The challenges of TCR-based therapy include those associated with TCR product manufacturing, patient selection, and preparation with lymphodepletion. Overcoming these challenges, and those posed by the immunosuppressive microenvironment, as well as developing next-generation strategies is essential to improving the efficacy and safety of TCR-based therapies. Optimization of technology to generate TCR product, treatment administration, and patient monitoring for adverse events is needed. The implementation of novel TCR strategies will require expansion of the TCR approach to patients with HLA haplotypes beyond HLA-A*02:01 and the discovery of novel tumor markers that are expressed in more patients and tumor types. Ongoing clinical trials will determine the ultimate role of TCR-based therapy in patients with solid tumors.

Preferentially expressed antigen in melanoma expression in nonmelanoma skin cancers and melanocytes in surrounding skin

BACKGROUND

Immunohistochemistry for preferentially expressed antigen in melanoma (PRAME) has been studied in melanocytic lesions but not nonmelanoma skin cancers (NMSCs). This study evaluated PRAME expression in NMSCs and dermoepidermal junction (DEJ) melanocytes in the surrounding skin.

METHODS

Ninety-nine NMSCs were studied: 23 Merkel cell carcinomas (MCCs), 25 well to poorly differentiated squamous cell carcinomas (SCCs), 14 basal cell carcinomas (BCCs), five basosquamous carcinomas, four sebaceous carcinomas, ten atypical fibroxanthomas, 11 dermatofibrosarcoma protuberans, and seven leiomyosarcomas. Staining quality was considered low or high intensity. Staining quantity was reported as negative 0%, 1% to 24%, 25% to 50%, and >50%. DEJ melanocyte PRAME expression was recorded.

RESULTS

Forty-eight percent of NMSCs showed PRAME expression, mostly low intensity in fewer than 25% of cells. High-intensity expression was noted in one poorly differentiated SCC, six BCCs, and seven MCCs. Only MCCs showed expression in greater than 25% of tumor cells. Focal DEJ melanocytes expressed high-intensity PRAME in 18% of cases, most commonly SCCs (11/23).

CONCLUSIONS

PRAME is negative or expressed with low intensity in a small percentage of NMSCs, with the exception of some MCC showing high-intensity and diffuse staining. Focal DEJ melanocytes showed high-intensity PRAME reactivity in the skin surrounding some NMSCs.

In Silico Design and Evaluation of PRAME+FliCΔD2D3 as a New Breast Cancer Vaccine Candidate

Background

The most prevalent cancer in women over the world is breast cancer. Immunotherapy is a promising method to effectively treat cancer patients. Among various immunotherapy methods, tumor antigens stimulate the immune system to eradicate cancer cells. Preferentially expressed antigen in melanoma (PRAME) is mainly overexpressed in breast cancer cells, and has no expression in normal tissues. FliCΔD2D3, as truncated flagellin (FliC), is an effective toll-like receptor 5 (TLR5) agonist with lower inflammatory responses. The objective of the present study was to utilize bioinformatics methods to design a chimeric protein against breast cancer.

Methods

The physicochemical properties, solubility, and secondary structures of PRAME+FliCΔD2D3 were predicted using the tools ProtParam, Protein-sol, and GOR IV, respectively. The 3D structure of the chimeric protein was built using I-TASSER and refined with GalaxyRefine, RAMPAGE, and PROCHECK. ANTIGENpro and VaxiJen were used to evaluate protein antigenicity, and allergenicity was checked using AlgPred and Allergen FP. Major histocompatibility complex )MHC( and cytotoxic T-lymphocytes )CTL( binding peptides were predicted using HLApred and CTLpred. Finally, B-cell continuous and discontinuous epitopes were predicted using ABCpred and ElliPro, respectively.

Results

The stability and solubility of PRAME+FliCΔD2D3 were analyzed, and its secondary and tertiary structures were predicted. The results showed that the derived peptides could bind to MHCs and CTLs. The designed chimeric protein possessed both linear and conformational epitopes with a high binding affinity to B-cell epitopes.

Conclusion

PRAME+FliCΔD2D3 is a stable and soluble chimeric protein that can stimulate humoral and cellular immunity. The obtained results can be utilized for the development of an experimental vaccine against breast cancer.

PRAME promotes epithelial-to-mesenchymal transition in triple negative breast cancer

Background

The triple negative breast cancer (TNBC) paradox marks a major challenge in the treatment-decision making process. TNBC patients generally respond better to neoadjuvant chemotherapy compared to other breast cancer patients; however, they have a substantial higher risk of disease recurrence. We evaluated the expression of the tumor-associated antigen PReferentially Antigen expressed in MElanoma (PRAME) as a prognostic biomarker in breast cancer and explored its role in cell migration and invasion, key hallmarks of progressive and metastatic disease.

Methods

TCGA and GTeX datasets were interrogated to assess the expression of PRAME in relation to overall and disease-free survival. The role of PRAME in cell migration and invasion was investigated using gain- and loss-of-function TNBC cell line models.

Results

We show that PRAME promotes migration and invasion of TNBC cells through changes in expression of E-cadherin, N-cadherin, vimentin and ZEB1, core markers of an epithelial-to-mesenchymal transition. Mechanistic analysis of PRAME-overexpressing cells showed an upregulation of 11 genes (SNAI1, TCF4, TWIST1, FOXC2, IL1RN, MMP2, SOX10, WNT11, MMP3, PDGFRB, and JAG1) and downregulation of 2 genes (BMP7 and TSPAN13). Gene ontology analyses revealed enrichment of genes that are dysregulated in ovarian and esophageal cancer and are involved in transcription and apoptosis. In line with this, interrogation of TCGA and GTEx data demonstrated an increased PRAME expression in ovarian and esophageal tumor tissues in addition to breast tumors where it is associated with worse survival.

Conclusions

Our findings indicate that PRAME plays a tumor-promoting role in triple negative breast cancer by increasing cancer cell motility through EMT-gene reprogramming. Therefore, PRAME could serve as a prognostic biomarker and/or therapeutic target in TNBC.

Genomic characterization of cervical cancer based on human papillomavirus status

OBJECTIVE

It is uncommon for cervical cancer patients to be diagnosed without a human papillomavirus (HPV) infection. As prophylactic vaccines against high-risk HPV types are an ineffective preventive measure for these patients it is essential to identify differential biomarkers that may be associated with detection, prognosis and novel targeted therapies. The objective of this study was to compare the two entities, HPV+ and HPV- cervical cancers, based on TCGA public data.

METHODS

We collected and analyzed clinical information of 299 cervical cancer patients as the first step, then identified differential expressed genes and conducted downstream analyses to characterize this tumor based on HPV status, including functional annotation, pathway mapping, survival analysis and comparative somatic mutation landscapes. We further inferred the likelihood of responding to traditional treatment including radiotherapy and chemotherapy.

RESULTS

It was found that HPV- tumors were likely to occur at an older age and were often adenocarcinomas or adenosquamous carcinomas, and there was no significant overall survival difference between HPV+ vs. HPV- tumors. Gene expression profiles of HPV+ and HPV- tumors differed especially in ANKRD7, SERPINB3, EMX2, MEI1, RNF212, RP11-13 K12.5, RP11-325F22.2 and ZFR2 which were significantly relevant to cervical cancer prognosis. TP53, ARID5B, ARID1A, CTNNB1 and PTEN were significantly differentially mutated between HPV+ and HPV- tumors. Results of radiotherapy analyses demonstrated that CDO1, PCDHB2 and MYOD1 were different between the two subsets. In addition, RP11-299 L17.3, SLC14A2, FGF18 and OASL represented different drug-sensitivity to cisplatin between both.

CONCLUSIONS

These potential biomarkers may offer insights to further personalize therapeutic decision-making to improve survival in HPV- cervical cancer patients.

Impact of Preferentially Expressed Antigen of Melanoma on the Prognosis of Hepatocellular Carcinoma

BACKGROUND

Retinoids, vitamin A and its derivatives, have an antitumor effect on hepatocellular carcinoma (HCC). The function of retinoids is exerted by the complex of retinoic acid (RA) with the heterodimer of retinoid X receptor and the RA receptor. The preferentially expressed antigen of melanoma (PRAME) acts as a dominant repressor of RA signaling by binding to the complex. The significance of PRAME on the prognosis of HCC remains to be clarified.

METHODS

PRAME mRNA expression was examined by quantitative real-time polymerase chain reaction in both tumor and non-tumor tissues of 100 HCC patients who received surgical resection. The effect of PRAME knockdown on DR5-mediated RA transcriptional activity was examined.

RESULTS

In tumor tissues, there were significant associations among PRAME expression, clinical stage, tumor markers, and tumor numbers. In non-tumor tissues, there were significant associations among PRAME expression, overall survival, and disease-free survival. The knockdown of PRAME caused no reduction in DR5-mediated transcriptional activity of RA, suggesting that PRAME acts via other mechanisms than the DR5 RA-responsive elements.

CONCLUSION

Our findings indicate that PRAME expression is a novel prognostic marker in HCC patients.

Preferentially Expressed Antigen of Melanoma Prevents Lung Cancer Metastasis

Lung cancer is the most common cause of cancer death worldwide. The poor survival rate is largely due to the extensive local invasion and metastasis. However, the mechanisms underlying the invasion and metastasis of lung cancer cells remain largely elusive. In this study, we examined the role of preferentially expressed antigen of melanoma (PRAME) in lung cancer metastasis. Our results show that PRAME is downregulated in lung adenocarcinoma and lung bone metastasis compared with normal human lung. Knockdown of PRAME decreases the expression of E-Cadherin and promotes the proliferation, invasion, and metastasis of lung cancer cells by regulating multiple critical genes, most of which are related to cell migration, including MMP1, CCL2, CTGF, and PLAU. Clinical data analysis reveals that the expression of MMP1 correlates with the clinical features and outcome of lung adenocarcinoma. Taken together, our data demonstrate that PRAME plays a role in preventing the invasion and metastasis of lung adenocarcinoma and novel diagnostic or therapeutic strategies can be developed by targeting PRAME.

Identification of Preferentially Expressed Antigen of Melanoma as a Potential Tumor Suppressor in Lung Adenocarcinoma

Background

Preferentially expressed antigen of melanoma (PRAME) is known as a tumor-associated antigen that is altered in a variety of malignancies, including lung cancer. However, the role of PRAME in lung cancer remains unclear.

Material/Methods

We analyzed the expression of PRAME in human lung adenocarcinomas and studied the function of PRAME using small interfering RNA (siRNA)-induced gene knockdown in lung cancer cell lines PC9 and A549.

Results

We found that PRAME expression is down-regulated in lung adenocarcinomas. Knockdown of PRAME promoted proliferation and suppressed apoptosis of PC9 and A549 cells.

Conclusions

In line with its roles in controlling cell growth, RPAME regulates multiple critical cell-growth related genes, including IGF1R oncogene. IGF1R up-regulation contributes to increase of cell growth upon the knockdown of PRAME. Taken together, our results suggest that PRAME has inhibitory roles in lung cancer.

Diagnostic marker signature for esophageal cancer from transcriptome analysis

Esophageal cancer is often diagnosed at an advanced stage. Diagnostic markers are needed for achieving a cure in esophageal cancer detecting and treating tumor cells earlier. In patients with locally advanced squamous cell carcinoma of the esophagus (ESCC), we profiled the gene expression of ESCC compared to corresponding normal biopsies for diagnostic markers by genome microarrays. Profiling of gene expression identified 4844 genes differentially expressed, 2122 upregulated and 2722 downregulated in ESCC. Twenty-three overexpressed candidates with best scores from significance analysis have been selected for further analysis by TaqMan low-density array-technique using a validation cohort of 40 patients. The verification rate was 100 % for ESCC. Twenty-two markers were additionally overexpressed in adenocarcinoma of the esophagus (EAC). The markers significantly overexpressed already in earlier tumor stages (pT1-2) of both histological subtypes (n = 19) have been clustered in a "diagnostic signature": PLA2G7, PRAME, MMP1, MMP3, MMP12, LIlRB2, TREM2, CHST2, IGFBP2, IGFBP7, KCNJ8, EMILIN2, CTHRC1, EMR2, WDR72, LPCAT1, COL4A2, CCL4, and SNX10. The marker signature will be translated to clinical practice to prove its diagnostic impact. This diagnostic signature may contribute to the earlier detection of tumor cells, with the aim to complement clinical techniques resulting in the development of better detection of concepts of esophageal cancer for earlier therapy and more favorite prognosis.

The potential of tumor-derived exosomes for noninvasive cancer monitoring

Tumor-derived exosomes (TEX) are emerging as a new type of cancer biomarker. TEX are membrane-bound, virus-size vesicles of endocytic origin present in all body fluids of cancer patients. Based on the expanding albeit incomplete knowledge of their biogenesis, secretion by tumor cells and cancer cell-specific molecular and genetic contents, TEX are viewed as promising, clinically-relevant surrogates of cancer progression and response to therapy. Preliminary proteomic, genetic and functional profiling of tumor cell-derived or cancer plasma-derived exosomes confirms their unique characteristics. Alterations in protein or nucleic acid profiles of exosomes in plasma of cancer patients responding to therapies appear to correlate with clinical endpoints. However, methods for TEX isolation and separation from the bulk of human plasma-derived exosomes are not yet established and their role as biomarkers remains to be confirmed. Further development and validation of TEX as noninvasive, liquid equivalents of tumor biopsies are necessary to move this effort forward.

Cancer stem cells in head and neck squamous cell carcinoma

Recent studies have demonstrated that cancer stem cells (CSC) play an important role in the pathobiology of head and neck squamous cell carcinomas (HNSCC). This subpopulation of undifferentiated, self-renewing cells is responsible for resistance to conventional anti-cancer therapy, cancer recurrence, metastasis and ability to form a heterogeneous tumor. CSC are identified on the basis of specific markers, including membrane proteins or cell enzymes, or by using their self-renewal properties. As their resistance to standard HNSCC treatment may eventually lead to the lack of treatment success, there is an urgent need to better understanding CSC biology and identify them as potential target new treatment modality.