ß-Ionone enhances the inhibitory effects of 5-fluorouracil on the proliferation of gastric adenocarcinoma cells by the GSK-3ß signaling pathway.

5-Fluorouracil (5-FU) is widely used in the treatment of gastric cancer, and the emergence of drug resistance and toxic effects has limited its application. Therefore, there is an urgent need for safe and effective novel drugs or new therapies. ß-Ionone (BI) is found in vegetables and fruits and possesses an inhibitory proliferation of tumor cells in vitro and in vivo. In this study, we investigated whether BI could enhance the inhibitory effects of 5-FU on the proliferation of gastric adenocarcinoma cells and the growth of gastric cancer cell xenografts in a mouse model. The effects of BI and 5-FU alone or their combination on the cell viability, apoptosis, and mitochondrial membrane potential, the cell cycle, and its related proteins-Cyclin D1, and CDK4 as well as PCNA and GSK-3ß were evaluated in SGC-7901 cells and MKN45 cells by MTT, MB, flow cytometry and Western blot. In addition, the effects of BI and 5-FU alone or their combination on the growth of SGC-7901 cell xenografts in nude mice were investigated. The results showed that BI significantly enhanced the sensitivity of gastric adenocarcinoma cells to 5-FU in vitro and in vivo, i.e. proliferation inhibited, apoptosis induced and GSK-3ß protein activated. Therefore, our results suggest that BI increases the antitumor effect of 5-FU on gastric adenocarcinoma cells, at least partly from an activated GSK-3ß signaling pathway.

FBXO45 Knockdown Restrains the Progression of Bladder Cancer via the ERK/Cyclin D1/CDK4 Pathway.

BACKGROUNDS: F-box protein 45 (FBXO45) has been implicated in the progression of several diseases. Whether FBXO45 is involved in the development of bladder cancer remains unclear. Thus, this study focused on the effect of FBXO45 on the malignant progression of bladder cancer cells. METHODS: FBXO45 small-interference fragment was transfected into RT4 and 5637 cells by liposome-mediated transfection, and the knockdown efficiency of FBXO45 was verified by Western blot assay. The growth rate between FBXO45 knockdown cell lines and control cell lines was compared by counting kit 8 and plate cloning experiments. The motility of bladder cancer cells was observed via the Transwell test and Wound healing test. The effects of FBXO45 silencing on apoptosis and cell division were confirmed by flow cytometry. Western blot assay was performed to determine the function of FBXO45 knockdown on key proteins of cell apoptosis and the ERK/Cyclin D1/CDK4 pathway. RESULTS: After FBXO45 knockdown, the proliferation of bladder cancer cells was blocked (p < 0.01), and the migration and invasion abilities were reduced (p < 0.01). FBXO45 knockdown reduced the number of S-phase cells (RT4, p < 0.01; 5637, p < 0.05) and enhanced the apoptotic rate (p < 0.01). FBXO45 knockdown decreased the levels of p-ERK1/2, CDK4 and Cyclin D1 (p < 0.01). CONCLUSIONS: This study revealed that FBXO45 plays a carcinogenic role in bladder cancer via the ERK/Cyclin D1/CDK4 pathway, which provides a reference for the clinical treatment of patients with bladder cancer.

Diagnostic Accuracy of Immunohistochemical Expression of p16, MDM2, and CDK4 in Well-Differentiated and De-Differentiated Liposarcoma in MDM2 Fluorescent in situ Hybridisation Confirmed Cases.

OBJECTIVE: To establish the diagnostic utility of immunohistochemistry markers p16 along with MDM2 and CDK-4 in confirming the diagnosis of well-differentiated and de-differentiated liposarcoma while taking Fluorescent in situ Hybridisation (FISH) as a gold standard. STUDY DESIGN: A cross-sectional study. Place and Duration of the Study: Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from 30th January 2022 to 30th June 2023. METHODOLOGY: A standard panel of three immunohistochemistry markers p16, MDM2, and CDK4 were applied to 36 cases of atypical lipomatous tumours, well-differentiated liposarcoma (WDLPS), and de-differentiated liposarcoma (DDLPS), on which the gold standard FISH was already performed. The sample size was calculated with the help of a WHO calculator taking prevalence 1-2% in Pakistani population. Qualitative variables such as gender and site of tumour were presented by calculating frequency and percentages and comparison of Immunohistochemistry results with FISH was done by using a 2x2 table. RESULTS: The sensitivity and specificity of this triple marker panel for detecting WDLPS/DDLPS were 43.47% and 15.38%, respectively. The sensitivity and specificity of CDK4 for detecting WDLPS / DDLPS were 82.6% and 15.4%, those of MDM2 were 73.9% and 61.5 %, and those of p16 were 60.9% and 53.8%, respectively. CONCLUSION: Among all three markers, CDK4 was the most sensitive and MDM2 was the most specific marker for detecting WDLPS-DDLPS. It also showed that a combination of these three markers improves the diagnostic credibility of the immunohistochemistry in diagnosing DDLPS and WDLPS but FISH is the most reliable and confirmatory method. KEY WORDS: De-differentiated liposarcoma, Well-differentiated liposarcoma, P16, CDK4, MDM2.

Breaking through therapeutic barriers: Insights into CDK4/6 inhibition resistance in hormone receptor-positive metastatic breast cancer.

The therapeutic landscape for hormone receptor-positive (HR+) breast carcinoma has undergone a significant transformation with the advent of cyclin-dependent kinase (CDK)4/6 inhibitors, particularly in combination with endocrine therapy as the primary regimen. However, the evolution of resistance mechanisms in response to CDK4/6 inhibitors in HR+ metastatic breast cancer presents substantial challenges in managing the disease. This review explores the diverse genomic landscape underlying resistance, including disturbances in the cell cycle, deviations in oncogenic signaling pathways, deficiencies in DNA damage response (DDR) mechanisms, and changes in the tumor microenvironment (TME). Additionally, it discusses potential strategies to surmount resistance, including advancements in endocrine therapy, targeted inhibition of cell cycle components, suppression of AKT/mTOR activation, exploration of the FGFR pathway, utilization of antibody-drug conjugates (ADCs), and integration of immune checkpoint inhibitors (ICIs) with endocrine therapy and CDK4/6 inhibitors, providing pathways for enhancing patient outcomes amidst treatment challenges.

Expression and prognostic value of cell-cycle-associated genes in lung squamous cell carcinoma.

BACKGROUND: Lung cancer continues to be a prevalent cause of cancer-related deaths worldwide, with lung squamous carcinoma (LUSC) being a significant subtype characterized by comparatively low survival rates. Extensive molecular studies on LUSC have been conducted; however, the clinical importance of cell-cycle-associated genes has rarely been examined. This study aimed to investigate the relationship between these genes and LUSC. METHODS: The expression trends of genes related to the cell cycle in a group of patients with LUSC were analyzed. Clinical information and mRNA expression data were obtained from The Cancer Genome Atlas via cBioportal. Multiple analyses have been performed to investigate the association between these genes and LUSC. RESULTS: Three clusters were identified based on the mRNA expression of 124 cell cycle-associated genes. Cluster 3 exhibited the worst prognosis. A comparative analysis showed that nine expressed genes differed distinctly among all the clusters. Among these nine genes, elevated expression of CDK4 was strongly associated with positive prognosis. Furthermore, the expression of ANAPC11, ANAPC5, and ORC4 correlated with the advancement of LUSC pathological stages. CONCLUSIONS: Gene expression profiles associated with the cell cycle across various LUSC subtypes were identified, highlighting that specific genes are related to prognosis and disease stages. Based on these results, new prognostic strategies, patient stratification, and targeted therapy trials have been conducted for LUSC.

Effect of Cyclin-Dependent Kinase 4/6 Inhibitors on Circulating Cells in Patients with Metastatic Breast Cancer.

The combination of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) with endocrine therapy (ET) is the standard-of-care for estrogen receptor (ER)-positive, HER2-negative (ER+/HER2- advanced/metastatic breast cancer (mBC). However, the impact of CDK4/6i on circulating immune cells and circulating tumor cells (CTCs) in patients receiving CDK4/6i and ET (CDK4/6i+ET) remains poorly understood. This was a prospective cohort study including 44 patients with ER+/HER2- mBC treated with CDK4/6i+ET in either first or second line. Peripheral blood samples were collected before (baseline) and 3 months (t2) after therapy. Immune cell's subsets were quantified by flow cytometry, and microfluidic-captured CTCs were counted and classified according to the expression of cytokeratin and/or vimentin. Patients were categorized according to response as responders (progression-free survival [PFS] ≥ 6.0 months; 79.1%) and non-responders (PFS < 6.0 months; 20.9%). CDK4/6i+ET resulted in significant changes in the hematological parameters, including decreased hemoglobin levels and increased mean corpuscular volume, as well as reductions in neutrophil, eosinophil, and basophil counts. Specific immune cell subsets, such as early-stage myeloid-derived suppressor cells, central memory CD4+ T cells, and Vδ2+ T cells expressing NKG2D, decreased 3 months after CDK4/6i+ET. Additionally, correlations between the presence of CTCs and immune cell populations were observed, highlighting the interplay between immune dysfunction and tumor dissemination. This study provides insights into the immunomodulatory effects of CDK4/6i+ET, underscoring the importance of considering immune dynamics in the management of ER+/HER2- mBC.

CDK4/6 inhibitors plus endocrine therapy vs. placebo plus endocrine therapy for HR+/HER2- advanced breast cancer: a phase III RCTs based meta-analysis.

BACKGROUND: Does incorporating Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors into endocrine therapy (ET) effectively enhance survival outcomes, notably overall survival (OS), among individuals with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer? This remains a clinical controversy. We compared the antitumor efficacy and adverse effects (AEs) between CDK4/6 inhibitors + ET (CET) and placebo + ET (PET) by conducting a phase III randomized controlled trials (RCTs) based meta-analysis. METHODS: Seven databases were searched to identify eligible studies, comprising Phase III RCTs comparing CET to PET. The primary endpoints were OS and progression-free survival (PFS), with secondary endpoints including responses and adverse events (AEs). RESULTS: Seven RCTs (DAWNA-2, MONALEESA-2, MONALEESA-3, MONALEESA-7, MONARCH-3, PALOMA-2, and PALOMA-4) were included. The CET group exhibited significantly improved OS (HR: 0.81 [0.74, 0.88]), PFS (HR: 0.57 [0.52, 0.63]), objective response rate (RR: 1.31 [1.20, 1.43]), and clinical benefit rate (RR: 1.11 [1.07, 1.15]). These benefits were consistent across almost all subgroups. Additionally, the CET group showed better overall survival rates (OSR) from 24 to 60 months (OSR 24-60 m) and progression-free survival rates (PFSR) from 6 to 60 months (PFSR 6-60 m). However, more total AEs, grade 3-5 AEs, and serious AEs were found in CET group. The top 5 grade 3-5 AEs in the CET group were neutropenia (59.39%), leukopenia (24.11%), decreased white blood cell count (12.99%), hypertension (7.03%), and increased alanine aminotransferase (5.91%). CONCLUSIONS: The superiority of CET over PET in HR+/HER2- advanced breast cancer is evident, showing improved survival and responses. Nonetheless, the higher incidence of AEs, specifically hematologic AEs, requires cautious attention.

Real-world experience with CDK4/6 inhibitors in hormone receptor-positive metastatic and recurrent breast cancer: findings from an Asian population.

PURPOSE: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) combined with endocrine therapy have demonstrated significant clinical benefits in progression-free and overall survival. This study investigates the outcomes associated with two kinds of CDK4/6i in patients with hormone receptor (HR)-positive metastatic and relapsed breast cancer to inform real-world evidence of treatment strategies. METHODS: This retrospective study included 340 Taiwanese patients with HR-positive advanced breast cancer from the Taipei Veterans General Hospital, between 2018 and 2023. We analyzed patient characteristics, treatment strategies and outcomes associated with two CDK4/6i. The efficacy of patients who experienced economic burden and interrupted CDK4/6i treatment after 2 years of National Health Insurance (NHI) reimbursement was also investigated. RESULTS: Patients receiving ribociclib and palbociclib showed no significant differences in age, histology, body mass index(BMI), or pathologic status. The distribution of disease status and endocrine therapy partners was comparable between the two groups. Dose reduction was similar, while patients with palbociclib tended to discontinue CDK4/6i usage, and those with ribociclib tended to switch to the other CDK4/6i or endocrine partners. There was no significant difference in progression-free survival (PFS) between the two CDK4/6i in the first-line setting. Adverse prognostic factors were increasing HER2 IHC score, higher Ki-67 levels, visceral and liver metastasis, prior chemotherapy, and endocrine therapy resistance, while higher BMI, bone-only metastasis, and letrozole treatment were associated with a lower risk of progression. The limited follow-up time in our study was insufficient to assess the outcomes of patients treated with interrupted CDK4/6i for up to two years under the NHI reimbursement policy. CONCLUSION: Treatment outcomes between the two types of CDK4/6i did not differ significantly, indicating the safety and efficacy of CDK4/6i for the Asian population. Ribociclib and palbociclib showed similar efficacy in PFS in the real-world setting.

Palbociclib-derived multifunctional molecules for lysosomal targeting and diagnostic-therapeutic integration.

Aim: Lysosomal pH changes are associated with drug resistance, cell growth and invasion of tumors, but effective and specific real-time monitoring of lysosomal pH compounds for cancer therapy is lacking. Materials & methods: Here, based on the covalent linkage of the anticancer drug palbociclib and fluorescent dye fluorescein isothiocyanate (FITC), we designed and developed a novel palbociclib-derived multifunctional molecule (Pal-FITC) for lysosomal targeting and diagnostic therapeutic integration. Results & discussion: Pal-FITC fluoresces is 20-fold stronger than that of FITC and shows a linear response in the pH range of 4.0-8.2 (R2 = 0.9901). Pal-FITC blocks cells in G1 phase via Cyclin D-CDK4/6-Rb. Conclusion: Our study provides new strategies for tumor-targeted imaging and personalized therapy.

Based on the covalent linkage of the anticancer drug and the fluorescent dye, we designed and developed a novel palbociclib-derived multifunctional molecule (Pal-FITC) for lysosomal targeting and diagnostic therapeutic integration. Pal-FITC responded linearly in the pH range of 4.0­8.2. In addition, Pal-FITC was able to effectively treat lung cancer without toxic side effects on normal cells. It has a significant cell cycle blocking phenomenon and blocks G1 phase cells via Cyclin D-CDK4/6-Rb. Our study provides a new strategy for tumor-targeted imaging and personalized therapy.

Comparative analysis of adverse events associated with CDK4/6 inhibitors based on FDA's adverse event reporting system: a case control pharmacovigilance study.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors marked a milestone in the breast cancer treatment. Due to the potential impact of adverse effects on treatment decisions and patient outcomes, careful consideration of the varying toxicities of CDK4/6 inhibitors is crucial, as three inhibitors-palbociclib, abemaciclib, and ribociclib-have been approved with differences in adverse event profiles. However, limitations in clinical trials call for urgent real-world safety studies to evaluate and compare the risk of adverse events (AEs) among these CDK4/6 inhibitors. Therefore, this study aimed to analyze AEs of CDK4/6 inhibitors and provide insights for clinical drug selection, using real world database. METHODS: The AEs of CDK4/6 inhibitors in the FDA Adverse Event Reporting System (2015-2022) were analyzed. Four disproportionality methods were used to detect safety signals: reporting odds ratio (ROR), proportional reporting ratio, Bayesian Confidence Neural Network Propagation, and Multi-Item Gamma Poisson Shrinker. Venn analysis was used to compare and select common and specific AEs. RESULTS: This study included 73,042 patients treated with palbociclib, 25,142 with ribociclib, and 7563 with abemaciclib. All three inhibitors had 27 common AEs. Palbociclib exhibited the highest ROR for hematologic toxicities, while ribociclib showed the highest ROR for macrocytosis, nail disorders, and hepatic lesions. Abemaciclib displayed the highest ROR for mucosal toxicity. Common signals for both palbociclib and ribociclib included hematologic toxicities, decreased immune responsiveness, and aphthous ulcers. Myelosuppression, oral pain, and pseudocirrhosis were common signals for palbociclib and abemaciclib. Anemia, hepatotoxicity, and pneumonitis were observed as common signals for ribociclib and abemaciclib. Furthermore, specific AEs associated with palbociclib included fatigue, alopecia, and stomatitis. For ribociclib, specific AEs included electrocardiogram QT prolongation, thrombocytopenia, and decreased hemoglobin. Abemaciclib was specifically linked to diarrhea, vomiting, and interstitial lung disease. CONCLUSION: Our analysis revealed that palbociclib showed a higher risk of hematologic toxicity. Ribociclib showed higher risks of hepatotoxicity, nephrotoxicity, and QT prolongation. Abemaciclib showed higher risks of hepatotoxicity, gastrointestinal effects, interstitial lung disease, and thrombosis. These findings provide valuable insights for CDK4/6 inhibitor selection.

SelK promotes glioblastoma cell proliferation by inhibiting ß-TrCP1 mediated ubiquitin-dependent degradation of CDK4.

BACKGROUND: Glioblastoma (GB) is recognized as one of the most aggressive brain tumors, with a median survival of 14.6 months. However, there are still some patients whose survival time was greater than 3 years, and the biological reasons behind this clinical phenomenon arouse our research interests. By conducting proteomic analysis on tumor tissues obtained from GB patients who survived over 3 years compared to those who survived less than 1 year, we identified a significant upregulation of SelK in patients with shorter survival times. Therefore, we hypothesized that SelK may be an important indicator related to the occurrence and progression of GBM. METHODS: Proteomics and immunohistochemistry from GB patients were analyzed to investigate the correlation between SelK and clinical prognosis. Cellular phenotypes were evaluated by cell cycle analysis, cell viability assays, and xenograft models. Immunoblots and co-immunoprecipitation were conducted to verify SelK-mediated ubiquitin-dependent degradation of CDK4. RESULTS: SelK was found to be significantly upregulated in GB samples from short-term survivors (≤ 1 year) compared to those from long-term survivors (≥ 3 years), and its expression levels were negatively correlated with clinical prognosis. Knocking down of SelK expression reduced GB cell viability, induced G0/G1 phase arrest, and impaired the growth of transplanted glioma cells in nude mice. Down-regulation of SelK-induced ER stress leads to a reduction in the expression of SKP2 and an up-regulation of ß-TrCP1 expression. Up-regulation of ß-TrCP1, thereby accelerating the ubiquitin-dependent degradation of CDK4 and ultimately inhibiting the malignant proliferation of the GB cells. CONCLUSION: This study discovered a significant increase in SelK expression in GB patients with poor prognosis, revealing a negative correlation between SelK expression and patient outcomes. Further mechanistic investigations revealed that SelK enhances the proliferation of GB cells by targeting the endoplasmic reticulum stress/SKP2/ß-TrCP1/CDK4 axis.

p16-dependent increase of PD-L1 stability regulates immunosurveillance of senescent cells.

The accumulation of senescent cells promotes ageing and age-related diseases, but molecular mechanisms that senescent cells use to evade immune clearance and accumulate in tissues remain to be elucidated. Here we report that p16-positive senescent cells upregulate the immune checkpoint protein programmed death-ligand 1 (PD-L1) to accumulate in ageing and chronic inflammation. We show that p16-mediated inhibition of cell cycle kinases CDK4/6 induces PD-L1 stability in senescent cells via downregulation of its ubiquitin-dependent degradation. p16-expressing senescent alveolar macrophages elevate PD-L1 to promote an immunosuppressive environment that can contribute to an increased burden of senescent cells. Treatment with activating anti-PD-L1 antibodies engaging Fcγ receptors on effector cells leads to the elimination of PD-L1 and p16-positive cells. Our study uncovers a molecular mechanism of p16-dependent regulation of PD-L1 protein stability in senescent cells and reveals the potential of targeting PD-L1 to improve immunosurveillance of senescent cells and ameliorate senescence-associated inflammation.

Autophagic degradation of CDK4 is responsible for G0/G1 cell cycle arrest in NVP-BEZ235-treated neuroblastoma.

BACKGROUND: CDK4 is highly expressed and associated with poor prognosis and decreased survival in advanced neuroblastoma (NB). Targeting CDK4 degradation presents a potentially promising therapeutic strategy compared to conventional CDK4 inhibitors. However, the autophagic degradation of the CDK4 protein and its anti-proliferation effect in NB cells has not been mentioned. RESULTS: We identified autophagy as a new pathway for the degradation of CDK4. Firstly, autophagic degradation of CDK4 is critical for NVP-BEZ235-induced G0/G1 arrest, as demonstrated by the overexpression of CDK4, autophagy inhibition, and blockade of autophagy-related genes. Secondly, we present the first evidence that p62 binds to CDK4 and then enters the autophagy-lysosome to degrade CDK4 in a CTSB-dependent manner in NVP-BEZ235 treated NB cells. Similar results regarding the interaction between p62 and CDK4 were observed in the NVP-BEZ235 treated NB xenograft mouse model. CONCLUSIONS: Autophagic degradation of CDK4 plays a pivotal role in G0/G1 cell cycle arrest in NB cells treated with NVP-BEZ235.

Copy number alterations in metastatic and early breast tumours: prognostic and acquired biomarkers of resistance to CDK4/6 inhibitors.

BACKGROUND: Copy number alterations (CNA) are acquired during the evolution of cancers from their early stage to metastatic stage. This study aims at analysing the clinical value of the identified metastasis-associated CNAs both in metastatic breast cancers (mBCs) and early breast cancers (eBCs). METHODS: Single-nucleotide polymorphism (SNP)-array was performed on 926 biopsies from mBC patients, enrolled in SAFIR02-BREAST prospective trial. CNA profiles of eBCs from The Cancer Genome Atlas Breast Invasive Carcinoma (n = 770), Molecular Taxonomy of Breast Cancer International Consortium (n = 1620) and PACS04 trial (n = 243) cohorts were used as references for comparing mBCs and eBCs CNA profiles. Overall survival was the considered survival endpoint. RESULTS: Among the twenty-one genes frequently altered in ER + /HER2- mBCs: focal amplification of TERT was associated with poor outcome in the ER + /HER2- mBC population. Among the ER + /HER2- mBCs patients for whom CDK4/6 inhibitors information before biopsies collection was available: we identified seven genes on post-treatment biopsies, including the cyclin-dependent kinase 4 (CDK4), which was amplified in 9.8% of the ER + /HER2- mBCs pretreated population, as compared to 1.5% in the ER + /HER2- mBCs unpretreated population (P = 2.82E-04) as well as the 3 eBC populations. CDK4 amplification was associated with poor outcome in the ER + /HER2- eBCs. CONCLUSIONS: This study provides insights into the biology of mBCs and identifies clinically useful genomic features for future improvement of breast cancer patient management.

Unveiling the genetic landscape of hereditary melanoma: From susceptibility to surveillance.

The multifactorial etiology underlying melanoma development involves an array of genetic, phenotypic, and environmental factors. Genetic predisposition for melanoma is further influenced by the complex interplay between high-, medium-, and low-penetrance genes, each contributing to varying degrees of susceptibility. Within this network, high-penetrance genes, including CDKN2A, CDK4, BAP1, and POT1, are linked to a pronounced risk for disease, whereas medium- and low-penetrance genes, such as MC1R, MITF, and others, contribute only moderately to melanoma risk. Notably, these genetic factors not only heighten the risk of melanoma but may also increase susceptibility towards internal malignancies, such as pancreatic cancer, renal cell cancer, or neural tumors. Genetic testing and counseling hold paramount importance in the clinical context of suspected hereditary melanoma, facilitating risk assessment, personalized surveillance strategies, and informed decision-making. As our understanding of the genomic landscape deepens, this review paper aims to comprehensively summarize the genetic underpinnings of hereditary melanoma, as well as current screening and management strategies for the disease.

Identification of CDK4/6 Inhibitors as Small Molecule NLRP3 Inflammasome Activators that Facilitate IL-1ß Secretion and T Cell Adjuvanticity.

Several FDA-approved adjuvants signal through the NLRP3 inflammasome and IL-1ß release. Identifying small molecules that induce IL-1ß release could allow targeted delivery and structure-function optimization, thereby improving safety and efficacy of next-generation adjuvants. In this work, we leverage our existing high throughput data set to identify small molecules that induce IL-1ß release. We find that ribociclib induces IL-1ß release when coadministered with a TLR4 agonist in an NLRP3- and caspase-dependent fashion. Ribociclib was formulated with a TLR4 agonist into liposomes, which were used as an adjuvant in an ovalbumin prophylactic vaccine model. The liposomes induced antigen-specific immunity in an IL-1 receptor-dependent fashion. Furthermore, the liposomes were coadministered with a tumor antigen and used in a therapeutic cancer vaccine, where they facilitated rejection of E.G7-OVA tumors. While further chemical optimization of the ribociclib scaffold is needed, this study provides proof-of-concept for its use as an IL-1 producing adjuvant in various immunotherapeutic contexts.

Completion axillary lymph node dissection for the identification of pN2-3 status as an indication for adjuvant CDK4/6 inhibitor treatment: a post-hoc analysis of the randomised, phase 3 SENOMAC trial.

BACKGROUND: In luminal breast cancer, adjuvant CDK4/6 inhibitors (eg, abemaciclib) improve invasive disease-free survival. In patients with T1-2, grade 1-2 tumours, and one or two sentinel lymph node metastases, completion axillary lymph node dissection (cALND) is the only prognostic tool available that can reveal four or more nodal metastases (pN2-3), which is the only indication for adjuvant abemaciclib in this setting. However, this technique can lead to substantial arm morbidity in patients. We aimed to pragmatically describe the potential benefit and harm of this strategy on the individual patient level in patients from the ongoing SENOMAC trial. METHODS: In the randomised, phase 3, SENOMAC trial, patients aged 18 years or older, of any performance status, with clinically node-negative T1-T3 breast cancer and one or two sentinel node macrometastases from 67 sites in five European countries (Denmark, Germany, Greece, Italy, and Sweden) were randomly assigned (1:1), via permutated block randomisation (random block size of 2 and 4) stratified by country, to either cALND or its omission (ie, they had a sentinel lymph node biopsy only). The primary outcome is overall survival, which is yet to be reported. In this post-hoc analysis, patients from the SENOMAC per-protocol population, with luminal oestrogen-receptor positive, HER2-negative, T1-2, histological grade 1-2 breast cancer, with tumour size of 5 cm or smaller were selected to match the characteristics of cohort 1 of the monarchE trial who would only have an indication for adjuvant abemaciclib if found to have 4 or more nodal metastases. The primary study objective was to determine the number of patients who developed patient-reported severe or very severe impairment of physical arm function after cALND (as measured by the Lymphedema Functioning, Disability, and Health [Lymph-ICF] Questionnaire) 1 year after surgery to avoid one invasive disease-free survival event at 5 years with 2 years of adjuvant abemaciclib, using invasive disease-free survival event data from cohort 1 of the monarchE trial. The SENOMAC trial is registered with ClincialTrials.gov, NCT02240472, and is closed to accrual and ongoing. FINDINGS: Between Jan 31, 2015, and Dec 31, 2021, 2766 patients were enrolled in SENOMAC and randomly assigned to cALND (n=1384) or sentinel node biopsy only (n=1382), of whom 2540 were included in the per-protocol population. 1705 (67%) of 2540 patients met this post-hoc study's eligibility criteria, of whom 802 (47%) had a cALND and 903 (53%) had a sentinel lymph node biopsy only. Median age at randomisation was 62 years (IQR 52-71), 1699 (>99%) of 1705 patients were female, and six (<1%) were male. Among 1342 patients who responded to questionnaires, after a median follow-up of 45·2 months (IQR 25·6-59·8; data cutoff Nov 17, 2023), patient-reported severe or very severe impairment of physical arm function was reported in 84 (13%) of 634 patients who had cALND versus 30 (4%) of 708 who had sentinel lymph node biopsy only (χ2 test p<0·0001). To avoid one invasive disease-free survival event at 5 years with adjuvant abemaciclib, cALND would need to be performed in 104 patients, and would result in nine patients having severe or very severe impairment of physical arm function 1 year after surgery. INTERPRETATION: As a method to potentially identify an indication for abemaciclib, and subsequently avoid invasive disease-free survival events at 5 years with 2 years of adjuvant abemaciclib, cALND carries a substantial risk of severe or very severe arm morbidity and so cALND should be discouraged for this purpose. FUNDING: Swedish Research Council, the Swedish Cancer Society, the Nordic Cancer Union, and the Swedish Breast Cancer Association.

The Effect of Concomitant Administration of Proton Pump Inhibitors on the Pharmacokinetics of CDK4/6 Inhibitors in Rats: Implications for the Evaluation of Hepatic and Transporter-Mediated Drug-Drug Interactions.

BACKGROUND AND OBJECTIVES: Numerous clinical concerns have been expressed regarding the potential worsening of cyclin-dependent kinase 4/6 inhibitor effects in breast cancer patients because of co-administration of proton pump inhibitors. Hence, this study evaluated the effects of proton pump inhibitors on the pharmacokinetics of palbociclib and ribociclib in terms of  cytochrome P450 (CYP) 3A4 and P-glycoprotein involvement. METHODS: The effects of omeprazole and rabeprazole on drug metabolism and efflux of these drugs were investigated using molecular docking, metabolic stability assay in rat liver microsomes, human recombinant CYP3A4 (rCYP3A4) enzymes, and Caco-2 cell monolayers, and in vivo pharmacokinetics with omeprazole and rabeprazole in (5 and 10 mg/kg) 30 min and 7 days before orally dosing palbociclib and ribociclib (10 mg/kg). RESULTS: Omeprazole and rabeprazole inhibited CYP3A4 enzyme activity in rCYP3A4 baculosomes with a 50-60% inhibition at 30 µM. Additionally, both omeprazole and rabeprazole (10 µm) significantly reduced the P-glycoprotein-mediated drug efflux of palbociclib and ribociclib. The 7-day pretreatment of omeprazole at a dose of 10 mg/kg resulted in 24% and 26% reductions in palbociclib's mean maximum plasma concentration) Cmax and area under the plasma concentration-time curve (AUC0-24 h), respectively. Palbociclib's pharmacokinetics were not significantly altered by the pretreatment with rabeprazole; however, ribociclib pharmacokinetics exhibited an 83.94% increase in AUC0-24 h. CONCLUSION: The findings indicate that long-term treatment with therapeutic doses of both omeprazole and rabeprazole can alter the pharmacokinetics of palbociclib and ribociclib. The co-administration of rabeprazole may alter the pharmacokinetics of palbociclib and ribociclib via CYP enzyme and P-glycoprotein inhibition.