Targeting BRD4: Potential therapeutic strategy for head and neck squamous cell carcinoma (Review)

Discovery of a potent and selective peptide inhibitor with d-amino acids targeting the BRD4 ET domain for renal cancer therapy

Renal cancer is a highly aggressive tumor that poses a serious threat to human health. BRD4, as an important epigenetic regulator, is tightly associated with the development of renal cancer. Given the unique biological stability of d-amino acids, they have shown great potential for application in the field of cancer therapy. Currently, there are no reports on d-amino acid inhibitors targeting the ET domain of BRD4. Herein, we discovered a peptide inhibitor containing d-amino acids (BEP-2) targeting the BRD4 ET domain through virtual screening. BEP-2 showed an excellent binding affinity for BRD4 (Kd = 0.45 ± 0.03 nM). MD simulations demonstrate that BEP-2 can stably bind to the BRD4 ET domain. Moreover, BEP-2 displayed good inhibitory activity against 786-O and ACHN renal cancer cells and maintained high stability in serum. Additionally, BEP-2 inhibited the growth of 786-O cell xenograft tumors in nude mice. In summary, these data imply that BEP-2 is a promising antitumor drug that offers new perspectives for the treatment of renal cancer.

The common yet enigmatic activity of histone tail clipping

Histone proteolysis is sometimes described as an extreme post-translational modification (PTM), as it removes both a stretch of histone sequence and any PTMs that were previously added to it. Such an acute and significant loss of information could trigger many different downstream effects, making it attractive as a mechanism for rapid gene silencing or activation. Yet protease activity is challenging to study and is often treated like background noise that is best kept as low as possible. As both histones and protease activity are highly abundant in most cells, evidence of proteolysis of histone tails - a.k.a. histone clipping - has often been dismissed as nonspecific noise. Yet over the past decades there have been several studies that suggest this activity should not be ignored, as it may represent a rare but relevant process that plays important roles in cell biology. Here I review the key studies that both support this argument and raise additional questions about the mechanisms and functions of histone clipping.

Use of DNA methylation patterns for early detection and management of lung cancer: Are we there yet?

Detecting lung cancer early is crucial for improving survival rates, yet it remains a significant challenge due to many cases being diagnosed at advanced stages. This review aims to provide advances in epigenetics which have highlighted DNA methylation patterns as promising biomarkers for early detection, prognosis, and treatment response in lung cancer. Techniques like bisulfite conversion followed by PCR, digital droplet polymerase chain reaction, and next-generation sequencing are commonly used for detecting these methylation patterns, which occur early in the cancer development process and can be detected in non-invasive samples like blood and sputum. Key genes such as SHOX2 and RASSF1A have demonstrated high sensitivity and specificity in clinical studies, making them crucial for diagnostic purposes. However, several challenges remain to be overcome before these biomarkers can be widely adopted for use in clinical practice. Standardizing the assays and validating their effectiveness are critical steps. Additionally, integrating methylation biomarkers with existing diagnostic tools could significantly enhance the accuracy of lung cancer detection, providing a more comprehensive diagnostic approach. Although progress has been made in understanding and utilizing DNA methylation patterns for lung cancer detection, more research and extensive clinical trials are necessary to fully harness their potential. These efforts will help establish the robustness of methylation patterns as biomarkers and therapeutic targets, ultimately leading to better prevention, diagnosis, and treatment strategies for lung cancer. In conclusion, DNA methylation states represent a promising avenue for advancing early detection, accurate diagnosis, and management of lung cancer.

A Rare Case of a Malignant Proliferating Trichilemmal Tumor: A Molecular Study Harboring Potential Therapeutic Significance and a Review of Literature

Malignant proliferating trichilemmal tumors (MPTTs), arising from the external root sheath of hair follicles, are exceptionally rare, with limited documentation of their genetic alterations. We present a case of a 64-year-old African American woman who initially presented with a gradually enlarging nodule on her posterior scalp. An initial biopsy at an outside hospital suggested metastatic adenocarcinoma or squamous cell carcinoma (SCC) of an uncertain origin. A subsequent wide local excision revealed a 2.0 cm tumor demonstrating characteristic trichilemmal keratinization, characterized by an abrupt transition from the nucleated epithelium to a laminated keratinized layer, confirming MPTT. Immunohistochemistry demonstrated diffuse p53 expression, patchy CD 34 expression, focal HER2 membranous expression, and patchy p16 staining (negative HPV ISH). A molecular analysis identified TP53 mutation and amplifications in the ERBB2 (HER2), BRD4, and TYMS. Additional gene mutations of uncertain significance included HSPH1, ATM, PDCD1 (PD-1), BARD1, MSH3, LRP1B, KMT2C (MLL3), GNA11, and RUNX1. Assessments for the homologous recombination deficiency, PD-L1 expression, gene rearrangement, altered splicing, and DNA mismatch repair gene expression were negative. The confirmation of ERBB2 (HER2) amplification in the MPTT through a molecular analysis suggests potential therapeutic avenues involving anti-HER2 monoclonal antibodies. The presence of the TP53 mutation, without the concurrent gene mutations typically observed in SCC, significantly aided in this differential diagnosis.

The Development and Evaluation of a Novel Highly Selective PET Radiotracer for Targeting BET BD1

Background/Objectives: Small molecules that interfere with the interaction between acetylated protein tails and the tandem bromodomains of BET (bromodomain and extra-terminal) family proteins are pivotal in modulating immune/inflammatory and neoplastic diseases. This study aimed to develop a novel PET imaging tracer, [11C]GSK023, that targets the N-terminal bromodomain (BD1) of BET family proteins with high selectivity and potency, thereby enriching the chemical probe toolbox for epigenetic imaging. Methods: [11C]GSK023, a radio-chemical probe, was designed and synthesized to specifically target the BET BD1. In vivo PET imaging evaluations were conducted on rodents, focusing on the tracer's distribution and binding specificity in various tissues. Blocking studies were performed to confirm the probe's selectivity and specificity. Results: The evaluations revealed that [11C]GSK023 demonstrated good uptake in peripheral organs with limited brain penetration. Further blocking studies confirmed the probe's high binding specificity and selectivity for the BET BD1 protein, underscoring its potential utility in epigenetic imaging. Conclusions: The findings suggest that [11C]GSK023 is a promising PET probe for imaging the BET BD1 protein, offering the potential to deepen our understanding of the roles of BET bro-modomains in disease and their application in clinical settings to monitor disease progression and therapeutic responses.

Histone modifications in head and neck squamous cell carcinoma

Head and neck cancer is the main cause of cancer death worldwide, with squamous cell carcinoma (HNSCC) being the second most frequent subtype. HNSCC poses significant health threats due to its high incidence and poor prognosis, underscoring the urgent need for advanced research. Histone modifications play a crucial role in the regulation of gene expression and influencing various biological processes. In the context of HNSCC, aberrant histone modifications are increasingly recognized as critical contributors to its development and pathologic progression. This review demonstrates the molecular mechanisms, by which histone modifications such as acetylation, methylation, phosphorylation, and ubiquitination, impact the pathogenesis of HNSCC. The dysregulation of histone-modifying enzymes, including histone acetyltransferases (HATs), histone deacetylases (HDACs), and histone methyltransferases (HMTs), is discussed for its role in altering chromatin structure and gene expression in HNSCC. Moreover, we will explore the potential of targeting histone modifications as a therapeutic strategy, highlighting current preclinical and clinical studies that investigate histone deacetylase inhibitors (HDIs) and other epigenetic drugs, referring to the completed and ongoing clinical trials on those medications.