Role of post-translational modifications of Sp1 in cancer: state of the art

The role of Bcl‑2 in controlling the transition between autophagy and apoptosis (Review)

The Bcl‑2 protein family serves a key role in maintaining cellular homeostasis by regulating the balance between autophagy and apoptosis. The present review aimed to summarize interactions of Bcl‑2 with key proteins, including Beclin 1, Bax and Bcl‑2 homologous antagonist/killer, as well as its influence on cellular processes such as mitophagy, nutrient sensing and endoplasmic reticulum stress response. The impact of post‑translational modifications of Bcl‑2, including phosphorylation, ubiquitination and sumoylation, is discussed with respect to their regulatory roles under stress. In pathological states, Bcl‑2 upregulation in cancer suppresses apoptosis and autophagy, thereby facilitating tumor survival and resistance to chemotherapy. Conversely, in neurodegenerative diseases, impaired autophagy and increased apoptosis contribute to neuronal loss. Therapeutic strategies targeting Bcl‑2 (for example inhibitors such as venetoclax, navitoclax, obatoclax and combination therapies involving autophagy modulators) were evaluated for their potential efficacy. There is lack of understanding of tissue‑specific functions of Bcl‑2 and its interactions with non‑coding RNAs. Future research should prioritize these areas and leverage advanced single‑cell technologies to elucidate the real‑time dynamics of Bcl‑2 in cell processes. The present review highlights the key role of Bcl‑2 in cell fate determination and highlights its potential as a therapeutic target, offering insight for the development of innovative treatments for cancer, neurodegenerative disorder and age‑related diseases.

Piperlongumine overcomes osimertinib resistance via governing ubiquitination-modulated Sp1 turnover

Non-small cell lung cancer (NSCLC) is a common cause of cancer-related deaths worldwide, and its incidence has been increasing in recent years. While targeted therapies like osimertinib, an epidermal growth factor receptor tyrosine kinase inhibitor, have brought about notable improvements in patient outcomes for advanced NSCLC, the challenge of acquired drug resistance persists. Here, we found that cellular mesenchymal-epithelial transition factor (c-Met) was highly expressed in osimertinib-resistant cells, and depletion of c-Met markedly inhibited the growth of osimertinib-resistant cells ex vivo and in vivo, suggesting that c-Met is a potential target to address osimertinib resistance. Through a screening process using a natural product compound library, we identified piperlongumine as a potent inhibitor to overcome osimertinib resistance. Furthermore, the combined treatment of piperlongumine and osimertinib exhibited robust antitumor effects in resistant cells, partially restoring their sensitivity to osimertinib. Additionally, we discovered that piperlongumine could enhance the interaction between E3 ligase RNF4 and Sp1, inhibit the phosphorylation of Sp1 at Thr739, facilitate the ubiquitination and degradation of Sp1, lead to c-Met destabilization, and trigger intrinsic apoptosis in resistant cells. In summary, our study sheds light on the potential of piperlongumine in overcoming osimertinib resistance, offering new strategies and perspectives for the clinical management of drug-resistant NSCLC.

Viral Appropriation of Specificity Protein 1 (Sp1): The Role of Sp1 in Human Retro- and DNA Viruses in Promoter Activation and Beyond

Specificity protein 1 (Sp1) is a highly ubiquitous transcription factor and one employed by numerous viruses to complete their life cycles. In this review, we start by summarizing the relationships between Sp1 function, DNA binding, and structural motifs. We then describe the role Sp1 plays in transcriptional activation of seven viral families, composed of human retro- and DNA viruses, with a focus on key promoter regions. Additionally, we discuss pathways in common across multiple viruses, highlighting the importance of the cell regulatory role of Sp1. We also describe Sp1-related epigenetic and protein post-translational modifications during viral infection and how they relate to Sp1 binding. Finally, with these insights in mind, we comment on the potential for Sp1-targeting therapies, such as repurposing drugs currently in use in the anti-cancer realm, and what limitations such agents would have as antivirals.

Transcription factor specificity protein (SP) family in renal physiology and diseases

Dysregulated specificity proteins (SPs), members of the C2H2 zinc-finger family, are crucial transcription factors (TFs) with implications for renal physiology and diseases. This comprehensive review focuses on the role of SP family members, particularly SP1 and SP3, in renal physiology and pathology. A detailed analysis of their expression and cellular localization in the healthy human kidney is presented, highlighting their involvement in fatty acid metabolism, electrolyte regulation, and the synthesis of important molecules. The review also delves into the diverse roles of SPs in various renal diseases, including renal ischemia/reperfusion injury, diabetic nephropathy, renal interstitial fibrosis, and lupus nephritis, elucidating their molecular mechanisms and potential as therapeutic targets. The review further discusses pharmacological modulation of SPs and its implications for treatment. Our findings provide a comprehensive understanding of SPs in renal health and disease, offering new avenues for targeted therapeutic interventions and precision medicine in nephrology.