Promotion of tumor angiogenesis and growth induced by low-dose antineoplastic agents via bone-marrow-derived cells in tumor tissues.

Background: More research is needed to solidify the basis for reasonable metronomic chemotherapy regimens due to the inconsistent clinical outcomes from studies on metronomic chemotherapy with antineoplastic agents, along with signs of a nonlinear dose-response relationship at low doses. The present study therefore explored the dose-response relationships of representative antineoplastic agents in low dose ranges and their underlying mechanisms.

Methods: Cyclophosphamide (CPA) and 5-fluorouracil (5-Fu) were employed to observe the effects of the frequent administration of low-dose antineoplastic agents on tumor growth, tumor angiogenesis, and bone-marrow-derived cell (BMDC) mobilization in mouse models.

Dual‑directional effect of vinorelbine combined with cisplatin or fluorouracil on tumor growth and metastasis in metronomic chemotherapy in breast cancer.

Metronomic chemotherapy (MCT) regimens may be associated with risks to the patient due to the ambiguity surrounding low dosages and schedules. In the present study, metronomic regimens of vinorelbine (NVB) combined with cisplatin (CDDP) or fluorouracil (5‑FU) were chosen to study the dose‑response associations with tumor growth and metastasis, along with the underlying mechanisms in angiogenesis, apoptosis and tumor immunity, using experimental techniques such as immunofluorescence, immunohistochemistry, western blotting and flow cytometry. The results demonstrated a dual‑directional pharmacological action of promoting and suppressing tumor growth or metastasis in BALB/c mice bearing a 4T1 tumor at certain low and high doses of the drugs.

Low-dose Cisplatin Induces Tumor Growth Mobilization of Proangiogenic Bone Marrow-derived Cells in Mouse Models.

Background/aim: It is generally accepted that low-dose metronomic (LDM) chemotherapy mostly exerts its antitumor effects by inhibiting tumor angiogenesis. However, there is some evidence that LDM chemotherapy subsequently promotes tumor angiogenesis under certain regimens in animal models. The mechanisms responsible for these contradictory results are unclear.

Quantitative evaluation and pharmacokinetic characteristics of the irreversible BTK inhibitor zanubrutinib in mouse plasma using LC-MS/MS.

Zanubrutinib (BGB-3111) belongs to the class of irreversible inhibitors of Bruton's tyrosine kinase (BTK) for treating B-cell malignancies. A validated assay with excellent sensitivity, selectivity, and simplicity is required to measure plasma concentration and investigate its pharmacokinetics. The plasma of mice containing zanubrutinib and roxithromycin (internal standard) was processed with acetonitrile for protein precipitation.

Promotion of tumor progression induced by continuous low-dose administration of antineoplastic agent gemcitabine or gemcitabine combined with cisplatin.

Major Finding: This study observes a previously neglected pharmacological phenomenon and investigates its mechanism of that the continuous low-dose administration of some antineoplastic agents in certain dose ranges can promote tumorigenesis and tumor progression in vitro and in vivo, through stimulation of tumor cell functions directly as well as enhancement of tumor angiogenesis by BMDCs recruitment indirectly. The results alert to a potential risk in current empirically based continuous low-dose chemotherapy regimens such as metronomic chemotherapy.

Background And Objectives: There are indications that certain antineoplastic agents at low dosages may exhibit abnormal pharmacological actions, such as promoting tumor growth.