Sitagliptin synergizes 5-fluorouracil efficacy in colon cancer cells through MDR1-mediated flux impairment and down regulation of NFκB2 and p-AKT survival proteins.

5-fluorouracil (5-FU) is an inexpensive treatment for colon cancer; however, its efficacy is limited by chemoresistance. This study investigates the combination therapy approach of 5-FU with Sitagliptin (Sita), a diabetic drug with potential cancer-modulating effects. The combination was evaluated in vitro and in silico, focusing on the effects of Sita and 5-FU on colon cancer cells. The results showed that the addition of Sita significantly decreased the IC50 of 5-FU compared to 5-Fu monotherapy. The study also found that Sita and 5-FU interact synergistically, with a combination index below 1. Sita successfully lowered the 5-FU dosage reduction index, decreasing the expression of MDR1 mRNA and p-AKT and NFκB2 subunits p100/p52 protein. Molecular docking analyses confirmed Sita's antagonistic action on MDR1 and thymidylate synthase proteins. The study concludes that sitagliptin can target MDR1, increase apoptosis, and significantly reduce the expression of p-AKT and NFκB2 cell-survival proteins. These effects sensitize colon cancer cells to 5-FU. Repurposing sitagliptin may enhance the anticancer effects of 5-FU at lower dosages.

Nanoliposomal irinotecan with fluorouracil and folinic acid, FOLFIRINOX, and S-1 as second-line treatment for unresectable pancreatic cancer after gemcitabine/nab-paclitaxel.

This study aimed to compare second-line treatment outcomes for patients with unresectable pancreatic cancer previously treated with gemcitabine plus nab-paclitaxel (GnP) therapy. We conducted an integrated analysis of two retrospective studies included 318 patients receiving nanoliposomal irinotecan + 5-fluorouracil/folinic acid (NFF) (n = 102), S-1 (n = 57), or FOLFIRINOX (n = 14) as second-line treatment. Median overall survival (OS) in the NFF group was 9.08 months, significantly better than S-1 (4.90 months, P = 0.002). FOLFIRINOX had a median OS of 4.77 months, not statistically different from NFF. Subgroup analyses of OS indicated NFF was generally superior, however, a statistical interaction was observed between the treatment regimen in serum Alb < 3.5 g/dL (P = 0.042) and serum CRP ≥ 0.3 mg/dL (P = 0.006). Median progression-free survival (PFS) was 2.93 months for NFF, significantly better than S-1 (2.53 months, P = 0.024), while FOLFIRINOX had a comparable PFS (3.04 months, P = 0.948). Multivariate analysis identified the serum CRP, serum CA19-9, duration of first-line GnP therapy, and use (yes/no) of S-1 for second-line treatment as independent predictors for OS. This study concludes that second-line NFF therapy demonstrated a more favorable OS compared to S-1 therapy, however, it is still important to consider the patient background characteristics while selecting the most appropriate treatment.

Additional chemoradiotherapy for superficial esophageal squamous cell carcinoma after near-circumferential or full-circumferential noncurative endoscopic submucosal dissection: a retrospective study.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a potentially efficient therapeutic intervention for superficial esophageal cancer. Additional treatment such as chemoradiotherapy (CRT) or esophagectomy is recommended in cases of muscularis mucosa invasion with positive resection margins or lymphovascular invasion or submucosal layer invasion, which are considered noncurative ESD, due to an increased risk of lymph node metastasis. However, the adequacy of additional CRT after near-circumferential or full-circumferential noncurative ESD has not been fully discussed. In this study, we retrospectively evaluated the efficacy and toxicity of additional CRT for superficial esophageal squamous cell carcinoma (SCC) after near-circumferential or full-circumferential noncurative ESD, which was defined as a mucosal defect measuring ≥ 3/4 of the esophageal circumference. METHODS: We retrospectively evaluated 24 patients who received additional CRT for superficial esophageal SCC after near-circumferential or full-circumferential noncurative ESD between 2012 and 2018. Elective nodal irradiation (ENI) was performed in all patients and boost irradiation (BI) was performed after ENI in 4 patients with positive resection margins. The prescription doses of ENI and BI were 41.4 Gy in 23 fractions and 9 Gy in 5 fractions, respectively. Concurrent chemotherapy (a combination of cisplatin or nedaplatin and 5-fluorouracil) was administered to all patients. RESULTS: The 3-year and 5-year overall survival rates were 92% and 78%, respectively, while the 3-year and 5-year progression-free survival rates were 83% and 70%, respectively. Grade 2 esophageal stenosis occurred in 8 (33%) patients. There was no case of Grade 3 or worse esophageal stenosis. Among them, 4 (17%) patients developed stenosis before additional CRT, which persisted after the completion of additional CRT. The remaining 4 (17%) patients developed de novo stenosis within 5 months following the completion of additional CRT. One patient (4%) still requires regular bougie dilation. Grade 3 and Grade 4 acute toxicity, including anemia, neutropenia, thrombocytopenia, and esophagitis occurred in 1 (4%) and 0 (0%), 6 (25%) and 1 (4%), 1 (4%) and 0 (0%), and 1 (4%) and 0 (0%) patients, respectively. One (4%) patient who underwent salvage CRT for the out-of-field lymph node recurrence died with acute myeloid leukemia. CONCLUSIONS: Additional CRT is a viable treatment option even in patients who have undergone near-circumferential or full-circumferential noncurative ESD. Esophageal stenosis after additional CRT following near-circumferential or full-circumferential noncurative ESD is manageable and acceptable.

Safety of first-line systemic therapy in patients with metastatic colorectal cancer: a network meta-analysis of randomized controlled trials.

OBJECTIVE: To evaluate the safety of first-line systemic therapy for metastatic colorectal cancer through network meta-analysis. METHODS: The literature from PubMed, Embase, Web of Science, and Cochrane Library databases was searched from the inception of the databases to August 15, 2023, and strict inclusion and exclusion criteria were applied to screen studies. The Cochrane Bias Risk Assessment Tool (RoB 2.0) was used to evaluate the quality of the included literature. Network meta-analysis was conducted using Stata 15.0 and R4.3.1 software to compare the incidence of adverse events (AEs) among different treatment regimens. RESULTS: A total of 53 randomized controlled trials, involving 17,351 patients with metastatic colorectal cancer (mCRC), were ultimately included, encompassing 29 different therapeutic approaches. According to SUCRA rankings, the CAPOX regimen is most likely to rank first in terms of safety, while the FOLFOXIRI + panitumumab regimen is most likely to rank last. In terms of specific AEs, the CAPOX regimen, whether used alone or in combination with targeted drugs (bevacizumab and cetuximab), is associated with a reduced risk of neutropenia and febrile neutropenia, as well as an increased risk of thrombocytopenia and diarrhea. The FOLFOX regimen, with or without bevacizumab, is linked to an increased risk of neutropenia and peripheral sensory neuropathy. The FOLFIRI/CAPIRI + bevacizumab regimen is associated with a reduced risk of peripheral sensory neuropathy. S-1 and S-1 + oxaliplatin are well-tolerated in terms of gastrointestinal reactions. The FOLFOXIRI regimen, whether used alone or in combination with targeted drugs, is associated with various AEs. CONCLUSION: In summary, the CAPOX regimen may be the safest option among the first-line systemic treatment regimens for mCRC patients, while the FOLFOXIRI + panitumumab regimen may be associated with a higher incidence of grade 3 or higher AEs.

In vitro cytoprotective and in vivo anti-oral mucositis effects of melatonin and its derivatives.

According to our preliminary study, melatonin and its N-amide derivatives (N-(2-(1-4-bromobenzoyl-5-methoxy-1H-indol-3-yl)ethyl)acetamide (BBM) and 4-bromo-N-(2-(5-methoxy-1H-indol-3-yl)ethyl)benzamide (EBM)) inhibited the marker of acute inflammation in tests in vitro and in vivo. The anti-inflammatory agent is intended for the prevention and treatment of chemotherapy-induced toxicity. In this study aimed to evaluate the effect of melatonin and its derivatives on mechanisms related to chemotherapy-induced oral mucositis by in vitro ROS and 5-FU-induced human keratinocyte cells as well as in vivo oral mucositis model. In in vitro H2O2-induced HaCaT cells, BBM had the highest level of protection (34.57%) at a concentration 50 µM, followed by EBM (26.41%), and melatonin (7.9%). BBM also protected cells against 5-FU-induced to 37.69-27.25% at 12.5-100 µM while EBM was 36.93-29.33% and melatonin was 22.5-11.39%. In in vivo 5-FU-induced oral mucositis in mice, melatonin, BBM, and EBM gel formulations protected tissue damage from 5-FU similar to the standard compound, benzydamine. Moreover, the weight of mice and food consumption recovered more quickly in the BBM group. These findings suggested that it was possible to develop BBM and EBM as new therapeutic agents for the treatment of oral mucositis.

Trends in the treatment of advanced pancreatic cancer.

Pancreatic cancer (PC) has the poorest prognosis among digestive cancers; only 15-20% of cases are resectable at diagnosis. This review explores multidisciplinary treatments for advanced PC, emphasizing resectability classification and treatment strategies. For locally advanced unresectable PC, systemic chemotherapy using modified FOLFIRINOX and gemcitabine with albumin-bound paclitaxel is standard, while the role of chemoradiation is debated. Induction chemotherapy followed by chemoradiation may be a promising therapy. Conversion surgery after initial chemotherapy or chemoradiotherapy offers favorable survival, however criteria for conversion need further refinements. For metastatic PC, clinical trials using immune checkpoint inhibitors and molecular targeted therapies are ongoing. Multidisciplinary approaches and further research are crucial for optimizing treatment and improving outcomes for advanced PC.

Thymoquinone Increases the Sensitivity of SW-480 Colon Cancer Cells to 5-Fluorouracil.

Background: Studies have concentrated on the therapeutic potential of thymoquinone (TQ), a natural polyphenol, in diverse malignancies, such as colorectal cancer. Nevertheless, the precise mechanisms of TQ-mediated anticancer properties are not yet fully elucidated. Objective: The present study has been designed to scrutinize the impact of TQ on 5-fluorouracil (5-FU)-mediated apoptosis in SW-480 cells. Materials and Methods: SW-480 cells were treated with TQ, 5-FU, and a combination of TQ + 5-FU. MTT assay was employed to assess cell viability. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to evaluate apoptotic markers comprising Bcl-2, Bax, and caspase-9 expression levels. The γ-H2AX protein expression was assessed by western blotting, and Annexin V flow cytometry was implemented to determine the apoptosis rate. Results: 5-FU significantly reversed the cell proliferation in a dose-dependent circumstance. The concurrent administration of TQ and 5-FU led to a substantial inhibition of cell growth in comparison to single treatments (p < 0.05). TQ also facilitated apoptosis via upregulating Bax and caspase-9 proapoptotic markers and suppressing antiapoptotic mediators, like Bcl-2. In addition, TQ augmented 5-FU-induced apoptosis in SW-480 cells. 5-FU, combined with TQ, increased the protein expression of γ-H2AX in SW-480 cells compared with groups treated with TQ and 5-FU alone. Conclusion: The present study's findings unveil the significance of TQ as a potential therapeutic substance in colorectal cancer, particularly through enhancing 5-FU-induced apoptosis.

Adjuvant Concurrent Chemoradiotherapy (CRT) plus Docetaxel-Cisplatin-Fluorouracil (DCF) versus CRT plus Fluorouracil-Folinic Acid (FUFA) in Stage III Gastric Cancer.

INTRODUCTION: Adjuvant chemoradiotherapy (CRT) is the optimal management strategy in resectable gastric cancer. There is a debate about the efficacy of more aggressive CRT plus chemotherapy regimens in adjuvant setting. This study aimed to compare the efficacy of adjuvant CRT plus docetaxel-cisplatin-fluorouracil (DCF) versus CRT plus fluorouracil-folinic acid (FUFA) in stage III gastric cancer. METHODS: Patients with a diagnosis of stage III gastric cancer treated with adjuvant therapy after curative resection were analyzed. Patients' disease characteristics and impacts of the regimens on median disease-free survival (DFS) and median overall survival (OS) were analyzed retrospectively. RESULTS: One hundred sixty-one patients (102 in FUFA arm and 59 in DCF arm) with a median age of 56.0 (29-79) were evaluated. In the DCF arm, there were more renal toxicities (31.6% vs 6.4% P < 0.001), emergency department admissions (64.9% vs 23.7%, P < 0.001), and dose reductions/treatment modifications in the DCF arm (51.6% vs 37.2, P < 0.001). The median follow-up was 23 months (1-124) in the FUFA arm and 26.0 months (1-77) in the DCF arm. The median DFS was 25.0 months (%95 CI, 12.7-37.2) in the DCF arm and 17.0 months (%95 CI, 2.6-31.3) in the FUFA arm, P = 0.66. The median OS was 28.0 months (%95 CI, 17.0-38.9) in the DCF arm and 25.0 months (%95 CI, 11.9-36.0) in the FUFA arm, P = 0.70. CONCLUSION: In conclusion, when compared with FUFA regimen, more aggressive therapy with DCF was more toxic and did not improve OS in adjuvant setting of stage III gastric cancer.

Innovative Strategies to Combat 5-Fluorouracil Resistance in Colorectal Cancer: The Role of Phytochemicals and Extracellular Vesicles.

Colorectal cancer (CRC) is a significant public health challenge, with 5-fluorouracil (5-FU) resistance being a major obstacle to effective treatment. Despite advancements, resistance to 5-FU remains formidable due to complex mechanisms such as alterations in drug transport, evasion of apoptosis, dysregulation of cell cycle dynamics, tumor microenvironment (TME) interactions, and extracellular vesicle (EV)-mediated resistance pathways. Traditional chemotherapy often results in high toxicity, highlighting the need for alternative approaches with better efficacy and safety. Phytochemicals (PCs) and EVs offer promising CRC therapeutic strategies. PCs, derived from natural sources, often exhibit lower toxicity and can target multiple pathways involved in cancer progression and drug resistance. EVs can facilitate targeted drug delivery, modulate the immune response, and interact with the TME to sensitize cancer cells to treatment. However, the potential of PCs and engineered EVs in overcoming 5-FU resistance and reshaping the immunosuppressive TME in CRC remains underexplored. Addressing this gap is crucial for identifying innovative therapies with enhanced efficacy and reduced toxicities. This review explores the multifaceted mechanisms of 5-FU resistance in CRC and evaluates the synergistic effects of combining PCs with 5-FU to improve treatment efficacy while minimizing adverse effects. Additionally, it investigates engineered EVs in overcoming 5-FU resistance by serving as drug delivery vehicles and modulating the TME. By synthesizing the current knowledge and addressing research gaps, this review enhances the academic understanding of 5-FU resistance in CRC, highlighting the potential of interdisciplinary approaches involving PCs and EVs for revolutionizing CRC therapy. Further research and clinical validation are essential for translating these findings into improved patient outcomes.

Cytostatic Bacterial Metabolites Interfere with 5-Fluorouracil, Doxorubicin and Paclitaxel Efficiency in 4T1 Breast Cancer Cells.

The microbiome is capable of modulating the bioavailability of chemotherapy drugs, mainly due to metabolizing these agents. Multiple cytostatic bacterial metabolites were recently identified that have cytostatic effects on cancer cells. In this study, we addressed the question of whether a set of cytostatic bacterial metabolites (cadaverine, indolepropionic acid and indoxylsulfate) can interfere with the cytostatic effects of the chemotherapy agents used in the management of breast cancer (doxorubicin, gemcitabine, irinotecan, methotrexate, rucaparib, 5-fluorouracil and paclitaxel). The chemotherapy drugs were applied in a wide concentration range to which a bacterial metabolite was added in a concentration within its serum reference range, and the effects on cell proliferation were assessed. There was no interference between gemcitabine, irinotecan, methotrexate or rucaparib and the bacterial metabolites. Nevertheless, cadaverine and indolepropionic acid modulated the Hill coefficient of the inhibitory curve of doxorubicin and 5-fluorouracil. Changes to the Hill coefficient implicate alterations to the kinetics of the binding of the chemotherapy agents to their targets. These effects have an unpredictable significance from the clinical or pharmacological perspective. Importantly, indolepropionic acid decreased the IC50 value of paclitaxel, which is a potentially advantageous combination.

The Therapeutic Role of NPS-1034 in Pancreatic Ductal Adenocarcinoma as Monotherapy and in Combination with Chemotherapy.

Pancreatic ductal adenocarcinoma (PDAC) poses a significant challenge in terms of diagnosis and treatment, with limited therapeutic options and a poor prognosis. This study explored the potential therapeutic role of NPS-1034, a kinase inhibitor targeting MET and AXL, in PDAC. The investigation included monotherapy with NPS-1034 and its combination with the commonly prescribed chemotherapy agents, fluorouracil and oxaliplatin. Our study revealed that NPS-1034 induces cell death and reduces the viability and clonogenicity of PDAC cells in a dose-dependent manner. Furthermore, NPS-1034 inhibits the migration of PDAC cells by suppressing MET/PI3K/AKT axis-induced epithelial-to-mesenchymal transition (EMT). The combination of NPS-1034 with fluorouracil or oxaliplatin demonstrated a synergistic effect, significantly reducing cell viability and inducing tumor cell apoptosis compared to monotherapies. Mechanistic insights provided by next-generation sequencing indicated that NPS-1034 modulates immune responses by inducing type I interferon and tumor necrosis factor production in PDAC cells. This suggests a broader role for NPS-1034 beyond MET and AXL inhibition, positioning it as a potential immunity modulator. Overall, these findings highlight the anticancer potential of NPS-1034 in PDAC treatment in vitro, both as a monotherapy and in combination with traditional chemotherapy, offering a promising avenue for further in vivo investigation before clinical exploration.

Complete response to chemotherapy in a 6-year survivor of metastatic pancreatic cancer.

A woman in her 40s underwent evaluation for abdominal pain, jaundice and acholic stools and was diagnosed with metastatic pancreatic head adenocarcinoma. She was enrolled in a clinical trial investigating the benefits of ibrutinib with nab-paclitaxel and gemcitabine, and subsequently received modified FOLFIRINOX. Over the course of 6 years on chemotherapy, she experienced complete regression of the pancreatic and liver lesions, as well as normalisation of her tumour markers. She has been off chemotherapy for 6 months with no evidence of disease and normal tumour markers. Despite advances in chemotherapy and surgical options, metastatic pancreatic adenocarcinoma continues to carry a grim prognosis. This case report demonstrates a rare case of a long-term survivor of unresectable metastatic pancreatic adenocarcinoma treated with chemotherapy alone.

A propensity score-matched comparison of neoadjuvant chemoradiotherapy with cisplatin-5FU and carboplatin-paclitaxel in locally advanced esophageal squamous cell carcinoma: A Turkish oncology group study.

BACKGROUND: Neoadjuvant treatment is the standard treatment in locally advanced ESCC. However, the optimal chemotherapy regimen is not known. METHOD: This is a retrospective observational cohort study conducted with propensity score matching. Patients with resectable ESCC from 13 tertiary centers from Türkiye were screened between January 2011 and December 2021. We compared the efficacy and safety of neoadjuvant chemoradiotherapy with the CF and the CROSS regimens in patients with ESCC. RESULTS: Three hundred and sixty-two patients were screened. Patients who received induction chemotherapy (n = 72) and CROSS-ineligible (n = 31) were excluded. Two hundred and fifty nine patients received neoadjuvant chemoradiotherapy. After propensity score matching (n = 97 in both groups), the mPFS was 18.4 months (95% CI, 9.3-27.4) and 25.7 months (95% CI, 15.6-35.7; p = 0.974), and the mOS was 35.2 months (95% CI, 18.9-51.5) and 39.6 months (95% CI 20.1-59.2; p = 0.534), in the CF and the CROSS groups, respectively. There was no difference between subgroups regarding PFS and OS. Compared with the CF group, the CROSS group had a higher incidence of neutropenia (34.0% vs. 62.9%, p < 0.001) and anemia (54.6% vs. 75.3%, p = 0.003) in all grades. On the other hand, there was no significant difference in grade 3-4 anemia, grade 3-4 neutropenia, and febrile neutropenia between groups. There were more dose reductions and dose delays in the CROSS group than in the CF group (11.3% vs. 3.1%, p = 0.026 and 34.0% vs. 17.5%, p = 0.009, respectively). The resection rate was 52.6% in the CF-RT and 35.1% in the CROSS groups (p = 0.014). CONCLUSION: Favorable PFS and pCR rates and a comparable OS were obtained with the CROSS regimen over the CF regimen as neoadjuvant chemoradiotherapy in patients with ESCC.

Adjuvant 5-fluorouracil and portal vein infusion chemotherapy followed by gemcitabine for pancreatic cancer.

BACKGROUND: Although adjuvant gemcitabine (GEM) monotherapy improves the overall survival (OS) of patients with resected pancreatic cancer, its efficacy requires further improvement. This multicenter, phase II study investigated the efficacy of adjuvant portal vein infusion (PVI) chemotherapy followed by GEM therapy in patients with resected pancreatic cancer. METHODS: 5-fluorouracil (250 mg/day) and heparin (2000 IU/day) PVI chemotherapy were combined with systemic administration of mitomycin C (4 mg; days 6, 13, 20, and 27) and cisplatin (10 mg; days 7, 14, 21, and 28) for 4 weeks (PI4W), followed by GEM (1000 mg/m2; days 1, 8, and 15 every 4 weeks for 6 months). The primary endpoint was relapse-free survival (RFS) and the secondary endpoints were OS and treatment completion. RESULTS: Between November 2010 and August 2013, 53 patients who underwent complete resection were enrolled, including 30, 20, and 3 patients who underwent pancreaticoduodenectomies and distal and total pancreatectomies, respectively. In total, 51 (96.2%) patients underwent R0 resection, of whom 3, 2, 12, 35, 0, and 1 had stages IA, IB, IIA, IIB, III, and IV cancer, respectively, and 47 (88.7%) patients completed PI4W. The median RFS was 22.0 months (1-, 3-, 5, and 10 years RFS: 64.9%, 38.1%, 38.1%, and 38.1%, respectively), whereas the median OS was 32.0 months (1-, 3-, 5, and 10 years OS:86.6%, 47.2%, 44.4%, and 44.4%, respectively). CONCLUSION: Treatment with PI4W followed by GEM for 6 months after surgery may be beneficial in patients undergoing curative resection of pancreatic cancer.

Cost-Effectiveness Analysis of Hepatic Arterial Chemotherapy for Advanced Hepatocellular Carcinoma in China: A Comparative Analysis of HAIC-FO and Sorafenib.

BACKGROUND The FOHAIC-1 trial showed hepatic arterial infusion chemotherapy with infusional fluorouracil, leucovorin, and oxaliplatin (HAIC-FO) improved survival, compared with sorafenib, in patients with advanced hepatocellular carcinoma (HCC). The aim of this study was to conduct a cost-effectiveness comparison between HAIC-FO and sorafenib from the perspective of the Chinese healthcare system. MATERIAL AND METHODS The economic evaluation was conducted between July 2023 and February 2024, spanning a 10-year investment horizon. A Markov model was developed to perform a cost-effectiveness analysis of HAIC-FO vs sorafenib. Health states incorporated in the model comprised progression-free disease, progressed disease, and death. Transition probabilities were derived from data obtained from the FOHAIC-1 trial. Incremental cost-effectiveness ratio (ICER) was calculated to evaluate cost-effectiveness. Additionally, one-way and probabilistic sensitivity analyses assessed the model's robustness. RESULTS The HAIC-FO group accrued a total cost of $22,781, whereas the sorafenib group totaled $18,795. In terms of effectiveness, the HAIC-FO group achieved 1.06 quality-adjusted life years (QALYs), whereas the sorafenib group attained 0.65 QALYs. Compared with sorafenib, HAIC-FO yielded an additional 0.41 QALYs at a cost of additional $3,985, resulting in an incremental cost of $9,720 per QALY gained. The one-way sensitivity analysis revealed the final ICER remained below the willingness-to-pay (WTP) threshold of $30,492 per QALY, when considering parameter fluctuations. Additionally, probabilistic sensitivity analysis indicated a 99.8% probability that the ICER for HAIC-FO compared with sorafenib would fall below the WTP threshold. CONCLUSIONS Compared with sorafenib, HAIC-FO emerged as a cost-effective first-line treatment option for patients facing advanced HCC in China.

Advancing targeted combination chemotherapy in triple negative breast cancer: nucleolin aptamer-mediated controlled drug release.

BACKGROUND: Triple-negative breast cancer (TNBC) is a recurrent, heterogeneous, and invasive form of breast cancer. The treatment of TNBC patients with paclitaxel and fluorouracil in a sequential manner has shown promising outcomes. However, it is challenging to deliver these chemotherapeutic agents sequentially to TNBC tumors. We aim to explore a precision therapy strategy for TNBC through the sequential delivery of paclitaxel and fluorouracil. METHODS: We developed a dual chemo-loaded aptamer with redox-sensitive caged paclitaxel for rapid release and non-cleavable caged fluorouracil for slow release. The binding affinity to the target protein was validated using Enzyme-linked oligonucleotide assays and Surface plasmon resonance assays. The targeting and internalization abilities into tumors were confirmed using Flow cytometry assays and Confocal microscopy assays. The inhibitory effects on TNBC progression were evaluated by pharmacological studies in vitro and in vivo. RESULTS: Various redox-responsive aptamer-paclitaxel conjugates were synthesized. Among them, AS1411-paclitaxel conjugate with a thioether linker (ASP) exhibited high anti-proliferation ability against TNBC cells, and its targeting ability was further improved through fluorouracil modification. The fluorouracil modified AS1411-paclitaxel conjugate with a thioether linker (FASP) exhibited effective targeting of TNBC cells and significantly improved the inhibitory effects on TNBC progression in vitro and in vivo. CONCLUSIONS: This study successfully developed fluorouracil-modified AS1411-paclitaxel conjugates with a thioether linker for targeted combination chemotherapy in TNBC. These conjugates demonstrated efficient recognition of TNBC cells, enabling targeted delivery and controlled release of paclitaxel and fluorouracil. This approach resulted in synergistic antitumor effects and reduced toxicity in vivo. However, challenges related to stability, immunogenicity, and scalability need to be further investigated for future translational applications.

Rapid determination of uracil in biological fluids at mercury thin film electrode for early detection of potential 5-fluorouracil toxicity due to dihydropyrimidine dehydrogenase deficiency.

Determination of plasma uracil was reported as a method for evaluation of Dihydropyrimidine dehydrogenase (DPD) activity that is highly demanded to ensure the safe administration of 5-fluorouracil (5-FU)-based therapies to cancer patients. This work reports the development of a simple electroanalytical method based on adsorptive stripping square wave voltammetry (AdSWV) at mercury film-coated glassy carbon electrode (MF/GCE) for the highly sensitive determination of uracil in biological fluids that can be used for diagnosis of decreased DPD activity. Due to the formation of the HgII-Uracil complex at the electrode surface, the accuracy of the measurement was not affected by the complicated matrices in biological fluids including human serum, plasma, and urine. The high sensitivity of the developed method results in a low limit of detection (≈1.3 nM) in human plasma samples, falling below the practical cut-off level of 15 ng mL-1 (≈0.14 µM). This threshold concentration is crucial for predicting 5-FU toxicity, as reported in buffer, and ≤1.15% in biological samples), and accuracy (recovery percentage close to 100%).

Effects of hypoxia on the growth of gastric cancer and the chemotherapeutic efficacy of 5-fluorouracil. / 缺氧对胃癌细胞生长和5-氟尿嘧啶化学治疗效果的影响.

OBJECTIVES: Hypoxia is an important cause of chemotherapy resistance in gastric cancer. However, little is known about the growth of gastric cancer under purely hypoxia conditions. This study aims to study the effect of hypoxia on the growth patterns of gastric cancer cells and explore the response of gastric cancer cells to the chemotherapeutic drug 5-fluorouracil (5-FU) in a hypoxic environment. METHODS: Gastric cancer cells MKN45 were cultured under 1% oxygen hypoxia and conventional air conditions. An intervention group with the addition of the chemotherapeutic drug 5-FU was also established. The proliferation and apoptosis of gastric cancer cells under different oxygen conditions and intervention groups were detected using the cell counting kit-8 (CCK-8) method, JC-1 mitochondrial membrane potential assay, and Annexin-V/PI double staining method. Cell cycle changes were detected by flow cytometry, and mitochondrial changes were detected using electron microscopy. RESULTS: In the absence of 5-FU intervention, compared with the normoxia group, the hypoxia group showed higher rates of early and late apoptosis and higher cell death rates as indicated by the JC-1 mitochondrial membrane potential assay, Annexin-V/PI double staining, and CCK-8 results. Flow cytometry results showed that the cell cycle was arrested in the G0/G1 phase without progression. Electron microscopy revealed more severe mitochondrial destruction. However, with 5-FU intervention, the hypoxia group showed lower apoptosis rates, more cell cycle progression, and less mitochondrial destruction compared with the normoxia group. CONCLUSIONS: Hypoxic environments promote apoptosis and even death in gastric cancer cells, but hypoxia counteracts the efficacy of the chemotherapeutic drug 5-FU, which may contribute to 5-FU chemotherapy resistance.