Cyclin-dependent kinases in cancer: Role, regulation, and therapeutic targeting

THF induces apoptosis by downregulating initiation, promotion, and progression phase biomarkers in skin and lung carcinoma

3,5,7-Trihydroxy-2-phenylchromen-4-one (THF) possesses a diverse range of pharmacological activities. Evidence suggests that THF exerts anticancer activity by distinct mechanisms of action. This study explores the anticancer potential of THF in human lung (A549) and skin (A431) cancer cells by employing different antiproliferative assays. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, neutral red uptake, sulphorhodamine B, and cell motility assays were used to confirm the anticancer potential of THF. Cell target-based and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were used to explore the effect of THF on the initiation, promotion and progression phase biomarkers of carcinogenesis. THF suppresses the activity of lipoxygenase-5 up to ~40% in both A549 and A431 cells and up to ~50% hyaluronidase activity in A549 cells. qRT-PCR assay reveals that THF inhibits the activity of phosphatidyl inositol-3 kinase/protein kinase B/mammalian target of rapamycin in both cell lines, which is responsible for the initiation of cancer. It also arrests the G2/M phase of the cell cycle in A431 cells and increases the sub-diploid population in both A549 and A431 cell lines which leads to cell death. Annexin V-FITC assay confirmed that THF induces apoptosis and necrosis in A431 and A549 cell lines. Further investigation revealed that THF not only enhances reactive oxygen species production but also modulates mitochondrial membrane potential in both cell lines. It significantly inhibits S-180 tumour formation at 5 and 10 mg/kg bw, i.p. dose. An acute skin toxicity study on mice showed that erythema and edema scores are within the acceptable range, besides acceptable drug-likeness properties and non-toxic effects on human erythrocytes. Conclusively, THF showed potent anticancer activity on skin and lung carcinoma cell lines, suppressed the level of the biomarkers and inhibited tumour growth in mice.

Cancer therapy by cyclin-dependent kinase inhibitors (CDKIs): bench to bedside

A major characteristic of cancer is dysregulated cell division, which results in aberrant growth of cells. Consequently, medicinal targets that prevent cell division would be useful in the fight against cancer. The primary regulator of proliferation is a complex consisting of cyclin and cyclin-dependent kinases (CDKs). The FDA has granted approval for CDK inhibitors (CDKIs) to treat metastatic hormone receptor-positive breast cancer. Specifically, CDK4/6 CDKIs block the enzyme activity of CDK4 and CDK6. Unfortunately, the majority of first-generation CDK inhibitors, also known as pan-CDK inhibitors because they target multiple CDKs, have not been authorized for clinical use owing to their serious side effects and lack of selection. In contrast to this, significant advancements have been created to permit the use of pan-CDK inhibitors in therapeutic settings. Notably, the toxicity and negative consequences of pan-CDK inhibitors have been lessened in recent years thanks to the emergence of combination therapy tactics. Therefore, pan-CDK inhibitors have renewed promise for clinical use when used in a combination regimen. The members of the CDK family have been reviewed and their primary roles in cell cycle regulation were covered in this review. Next, we provided an overview of the state of studies on CDK inhibitors.

Insights into Nimbolide molecular crosstalk and its anticancer properties

Nimbolide, one of the main ingredients constituent of Azadirachta indica (neem) leaf extract, has garnered attention for its potential as an anticancer agent. Its efficacy against various cancers and chemopreventive action has been demonstrated through numerous in vivo and in vitro studies. This updated review aims to comprehensively explore the chemopreventive and anticancer properties of nimbolide, emphasizing its molecular mechanisms of action and potential therapeutic applications in oncology. The review synthesizes evidence from various studies that examine nimbolide's roles in apoptosis induction, anti-proliferation, cell death, metastasis inhibition, angiogenesis suppression, and modulation of carcinogen-metabolizing enzymes. Nimbolide exhibits multifaceted anticancer activities, including the modulation of multiple cell signaling pathways related to inflammation, invasion, survival, growth, metastasis, and angiogenesis. However, its pharmacological development is still in the early stages, mainly due to limited pharmacokinetic and comprehensive long-term toxicological studies. Nimbolide shows promising anticancer and chemopreventive properties, but there is need for systematic preclinical pharmacokinetic and toxicological research. Such studies are essential for establishing safe dosage ranges for first-in-human clinical trials and further advancing nimbolide's development as a therapeutic agent against various cancers. The review highlights the potential of nimbolide in cancer treatment and underscores the importance of rigorous preclinical evaluation to realize its full therapeutic potential.

Unveiling the potential effects of resveratrol in lung cancer treatment: Mechanisms and nanoparticle-based drug delivery strategies

Lung cancer ranks among the most prevalent forms of cancer and remains a significant factor in cancer-related mortality across the world. It poses significant challenges to healthcare systems and society as a whole due to its high incidence, mortality rates, and late-stage diagnosis. Resveratrol (RV), a natural compound found in various plants, has shown potential as a nanomedicine for lung cancer treatment. RV has varied effects on cancer cells, including promoting apoptosis by increasing pro-apoptotic proteins (Bax and Bak) and decreasing anti-apoptotic proteins (Bcl-2). It also hinders cell proliferation by influencing important signaling pathways (MAPK, mTOR, PI3K/Akt, and Wnt/β-catenin) that govern cancer progression. In addition, RV acts as a potent antioxidant, diminishing oxidative stress and safeguarding cells against DNA damage. However, using RV alone in cancer treatment has drawbacks, such as low bioavailability, lack of targeting ability, and susceptibility to degradation. In contrast, nanoparticle-based delivery systems address these limitations and hold promise for improving treatment outcomes in lung cancer; nanoparticle formulations of RV offer advantages such as improved drug delivery, increased stability, controlled release, and targeted delivery to lung cancer cells. This article will provide an overview of lung cancer, explore the potential of RV as a therapeutic agent, discuss the benefits and challenges of nanoparticle-based drug delivery, and highlight the promise of RV nanoparticles for cancer treatment, including lung cancer. By optimizing these systems for clinical application, future studies aim to enhance overall treatment outcomes and improve the prognosis for lung cancer patients.

Enhancing Cervical Cancer Screening: Review of p16/Ki-67 Dual Staining as a Promising Triage Strategy

Cervical cancer, primarily caused by high-risk human papillomavirus (HR-HPV) types 16 and 18, is a major global health concern. Persistent HR-HPV infection can progress from reversible precancerous lesions to invasive cervical cancer, which is driven by the oncogenic activity of human papillomavirus (HPV) genes, particularly E6 and E7. Traditional screening methods, including cytology and HPV testing, have limited sensitivity and specificity. This review explores the application of p16/Ki-67 dual-staining cytology for cervical cancer screening. This advanced immunocytochemical method allows for simultaneously detecting p16 and Ki-67 proteins within cervical epithelial cells, offering a more specific approach for triaging HPV-positive women. Dual staining and traditional methods are compared, demonstrating their high sensitivity and negative predictive value but low specificity. The increased sensitivity of dual staining results in higher detection rates of CIN2+ lesions, which is crucial for preventing cervical cancer progression. However, its low specificity may lead to increased false-positive results and unnecessary biopsies. The implications of integrating dual staining into contemporary screening strategies, particularly considering the evolving landscape of HPV vaccination and changes in HPV genotype prevalence, are also discussed. New guidelines and further research are necessary to elucidate the long-term effects of integrating dual staining into screening protocols.

Ubiquitination and deubiquitination: Implications on cancer therapy

The ubiquitin proteasomal system (UPS) represents a highly regulated protein degradation pathway essential for maintaining cellular homeostasis. This system plays a critical role in several cellular processes, which include DNA damage repair, cell cycle checkpoint control, and immune response regulation. Recently, the UPS has emerged as a promising target for cancer therapeutics due to its involvement in oncogenesis and tumor progression. Here we aim to summarize the key aspects of the UPS and its significance in cancer therapeutics. We begin by elucidating the fundamental components of the UPS, highlighting the role of ubiquitin, E1-E3 ligases, and the proteasome in protein degradation. Furthermore, we discuss the intricate process of ubiquitination and proteasomal degradation, emphasizing the specificity and selectivity achieved through various signaling pathways. The dysregulation of the UPS has been implicated in cancer development and progression. Aberrant ubiquitin-mediated degradation of key regulatory proteins, such as tumor suppressors and oncoproteins, can lead to uncontrolled cell proliferation, evasion of apoptosis, and metastasis. We outline the pivotal role of the UPS in modulating crucial oncogenic pathways, including the regulation of cyclins, transcription factors, Replication stress components and DNA damage response. The increasing recognition of the UPS as a target for cancer therapeutics has spurred the development of small molecules, peptides, and proteasome inhibitors with the potential to restore cellular balance and disrupt tumor growth. We provide an overview of current therapeutic strategies aimed at exploiting the UPS, including the use of proteasome inhibitors, deubiquitinating enzyme inhibitors, and novel E3 ligase modulators. We further discuss novel emerging strategies for the development of next-generation drugs that target proteasome inhibitors. Exploiting the UPS for cancer therapeutics offers promising avenues for developing innovative and effective treatment strategies, providing hope for improved patient outcomes in the fight against cancer.

Thymoquinone, a Novel Multi-Strike Inhibitor of Pro-Tumorigenic Breast Cancer (BC) Markers: CALR, NLRP3 Pathway and sPD-L1 in PBMCs of HR+ and TNBC Patients

Breast cancer (BC) is not only a mass of malignant cells but also a systemic inflammatory disease. BC pro-tumorigenic inflammation has been shown to promote immune evasion and provoke BC progression. The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is activated when pattern recognition receptors (PRRs) sense danger signals such as calreticulin (CALR) from damaged/dying cells, leading to the secretion of interleukin-1β (IL-1β). CALR is a novel BC biological marker, and its high levels are associated with advanced tumors. NLRP3 expression is strongly correlated with an elevated proliferative index Ki67, BC progression, metastasis, and recurrence in patients with hormone receptor-positive (HR+) and triple-negative BC (TNBC). Tumor-associated macrophages (TAMs) secrete high levels of IL-1β promoting endocrine resistance in HR+ BC. Recently, an immunosuppressive soluble form of programmed death ligand 1 (sPD-L1) has been identified as a novel prognostic biomarker in triple-negative breast cancer (TNBC) patients. Interestingly, IL-1β induces sPD-L1 release. BC Patients with elevated IL-1β and sPD-L1 levels show significantly short progression-free survival. For the first time, this study aims to investigate the inhibitory impact of thymoquinone (TQ) on CALR, the NLRP3 pathway and sPD-L1 in HR+ and TNBC. Blood samples were collected from 45 patients with BC. The effect of differing TQ concentrations for different durations on the expression of CALR, NLRP3 complex components and IL-1β as well as the protein levels of sPD-L1 and IL-1β were investigated in the peripheral blood mononuclear cells (PBMCs) and TAMs of TNBC and HR+ BC patients, respectively. The findings showed that TQ significantly downregulated the expression of CALR, NLRP3 components and IL-1β together with the protein levels of secreted IL-1β and sPD-L1. The current findings demonstrated novel immunomodulatory effects of TQ, highlighting its potential role not only as an excellent adjuvant but also as a possible immunotherapeutic agent in HR+ and TNBC patients.

Quinazolinone derivatives as new potential CDK4/6 inhibitors, apoptosis inducers and radiosensitizers for breast cancer

Background: Targeting CDK4/6 has advanced breast cancer treatment. Herein, new quinazolinones were synthesized with acetamide linkers as potential anti-breast cancer agents. Methods & results: In vitro cytotoxic evaluation on human breast cancer cell lines (MCF7 and MDA-MB-231) identified 1,3-benzodioxole (5d) to be of the highest potency. It showed good inhibitory activity on CDK4/6. Compound 5d arrested the cell cycle at the G1-phase, caused induction of early and late apoptosis in an Annexin V-FITC assay, led to an increase in the level of caspase-3 and upregulated Bax expression and downregulated Bcl-2 in MCF7 cells. Compound 5d showed good radiosensitizing activity when combined with a single dose of 8-Gy γ-radiation. Conclusion: This study introduces quinazolinone scaffolds as new CDK4/6 inhibitors for breast cancer.