Efficacy and safety of anlotinib, a multikinase angiogenesis inhibitor, in combination with epirubicin in preclinical models of soft tissue sarcoma

Abstract

Background: Anlotinib is a novel, orally administered, multitarget receptor tyrosine kinase inhibitor. It functions by inhibiting tumor angiogenesis and proliferative signaling pathways. In this study, we aimed to investigate the efficacy and safety of anlotinib plus epirubicin in a sarcoma patient-derived xenografts (PDX) model.

Methods: We firstly established a PDX model using fresh tumor tissues that were surgically removed from a patient diagnosed with malignant fibrous histiocytoma. Thirty-six PDX models were divided into six groups and treated with anlotinib alone (low-dose, 1.5 or high-dose, 3.0 mg/kg/day, oral gavage), or with anlotinib plus epirubicin (3.0 mg/kg/once weekly, i.p.) when the tumors grew to 150-200 mm³ . After 5 weeks of treatment, the mice were sacrificed, and the tumors were measured by weight and processed for IHC and H&E staining. IHC staining was performed to detect CD31, EGFR, MVD, and Ki-67 on paraffin sections. H&E stainings were performed to examine the microcosmic changes that occurred in the tumor tissues and myocardium, respectively.

Results: After 5 weeks, treatment with anlotinib or epirubicin alone significantly inhibited tumor growth in the sarcoma PDX model compared with the vehicle control. Tumor volume in the high-dose anlotinib group was significantly smaller than the low-dose anlotinib group (P < .001). Combined high-dose anlotinib and epirubicin treatment resulted in the most pronounced tumor inhibition. In the groups treated with the anlotinib-containing regimen, the expression levels of CD31, EGFR, MVD, and Ki-67 were significantly low. The weight in each group had no statistical differences; the same applied to the hepatic function, cardiac function, and toxicity.

Conclusions: High-dose anlotinib combined with epirubicin was an effective and safe therapy for STS.

Keywords: anlotinib; combination; epirubicin; patient-derived xenografts; soft tissue sarcoma; tyrosine kinase inhibitor.

Figure 1

Effect of Anlotinib on the sarcoma PDX model. A, Tumor growth curve of each group. B, Macroscopic examination of the resected tumor. C, Tumor weight of each group. D, Body weight changes over the treatment period.Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 2

The hepatic and cardiac function of mice at the end of study. A, Serum levels of ALT. B, Serum levels of AST. C, Serum levels of CK‐MB. C, Serum levels of BNP. Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 3

Anlotinib promoted tumor apoptosis and necrosis. The H&E staining of representative tumor sections in each group. ×400. Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 4

The representative myocardial cell morphology of mice in each group under the H&E staining. ×400. Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 5

The representative myocardial cell morphology of mice in each group under the H&E staining. ×400. Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 6

Anlotinib decreased tumor angiogenesis and cell proliferation. IHC analysis of CD31, EGFR, MVD, and Ki‐67 expression of representative tumor sections in each group. ×400. Group 1, vehicle control (DD‐H2O); Group 2, low‐dose anlotinib (1.5 mg/kg per day); Group 3, high‐dose anlotinib (3.0 mg/kg per day); Group 4, epirubicin (2.5 mg/kg per week); Group 5, low‐dose anlotinib (1.5 mg/kg per day) and epirubicin (2.5 mg/kg per week); Group 6, high‐dose anlotinib (3.0 mg/kg per day) and epirubicin (2.5 mg/kg per week)

Figure 7

The potential mechanisms of anlotinib in the treatment of STS