Enhanced anti-melanoma efficacy through a combination of the armed oncolytic adenovirus ZD55-IL-24 and immune checkpoint blockade in B16-bearing immunocompetent mouse model.

Although the recent treatment in melanoma through the use of anti-PD-1 immunotherapy is successful, the efficacy of this approach remains to be improved. Here, we explore the feasibility of combination strategy with the armed oncolytic adenovirus ZD55-IL-24 and PD-1 blockade. We find that combination therapy with localized ZD55-IL-24 and systemic PD-1 blockade leads to synergistic inhibition of both local and distant established tumors in B16-bearing immunocompetent mouse model. Our further mechanism investigation reveals that synergistic therapeutic effect is associated with marked promotion of tumor immune infiltration and recognition in both local and distant tumors as well as spleens. PD-1 blockade has no obvious effect on promotion of tumor immune infiltration and recognition. Localized therapy with ZD55-IL-24, however, can help PD-1 blockade to overcome the limitation of relatively low tumor immune infiltration and recognition. This study provides a rationale for investigation of such combination therapy in the clinic.

Optimization of the Administration Strategy for the Armed Oncolytic Adenovirus ZD55-IL-24 in Both Immunocompromised and Immunocompetent Mouse Models.

ZD55-IL-24 is an armed oncolytic adenovirus similar but superior to ONYX-015. Virotherapeutic strategies using ZD55-IL-24 have been demonstrated to be effective against several cancer types. However, it is unclear whether the traditional administration strategy is able to exert the maximal antitumor efficacy of ZD55-IL-24. In this study, we sought to optimize the administration strategy of ZD55-IL-24 in both A375-bearing immunocompromised mouse model and B16-bearing immunocompetent mouse model. Although the underlying antitumor mechanisms are quite different, the obtained results are similar in these two mouse tumor models. We find that the antitumor efficacy of ZD55-IL-24 increases as injection times increase in both of these two models. However, no obvious increase of efficacy is observed as the dose of each injection increases. Our further investigation reveals that the administration strategy of sustained ZD55-IL-24 therapy can achieve a better therapeutic effect than the traditional administration strategy of short-term ZD55-IL-24 therapy. Furthermore, there is no need to inject every day; every 2 or 3 days of injection achieves an equivalent therapeutic efficacy. Finally, we find that the sustained rather than the traditional short-term ZD55-IL-24 therapy can synergize with anti-PD-1 therapy to reject tumors in B16-bearing immunocompetent mouse model. These findings suggest that the past administration strategy of ZD55-IL-24 is in fact suboptimal and the antitumor efficacy can be further enhanced through administration strategy optimization. This study might shed some light on the development of clinically applicable administration regimens for ZD55-IL-24 therapy.

The armed oncolytic adenovirus ZD55-IL-24 eradicates melanoma by turning the tumor cells from the self-state into the nonself-state besides direct killing.

ZD55-IL-24 is similar but superior to the oncolytic adenovirus ONYX-015, yet the exact mechanism underlying the observed therapeutic effect is still not well understood. Here we sought to elucidate the underlying antitumor mechanism of ZD55-IL-24 in both immunocompetent and immunocompromised mouse model. We find that ZD55-IL-24 eradicates established melanoma in B16-bearing immunocompetent mouse model not through the classic direct killing pathway, but mainly through the indirect pathway of inducing systemic antitumor immunity. Inconsistent with the current prevailing view, our further results suggest that ZD55-IL-24 can induce antitumor immunity in B16-bearing immunocompetent mouse model in fact not due to its ability to lyse tumor cells and release the essential elements, such as tumor-associated antigens (TAAs), but due to its ability to put a "nonself" label in tumor cells and then turn the tumor cells from the "self" state into the "nonself" state without tumor cell death. The observed anti-melanoma efficacy of ZD55-IL-24 in B16-bearing immunocompetent mouse model was practically caused only by the viral vector. In addition, we also notice that ZD55-IL-24 can inhibit tumor growth in B16-bearing immunocompetent mouse model through inhibiting angiogenesis, despite it plays only a minor role. In contrast to B16-bearing immunocompetent mouse model, ZD55-IL-24 eliminates established melanoma in A375-bearing immunocompromised mouse model mainly through the classic direct killing pathway, but not through the antitumor immunity pathway and anti-angiogenesis pathway. These findings let us know ZD55-IL-24 more comprehensive and profound, and provide a sounder theoretical foundation for its future modification and drug development.

[Effect of ligustrazine on airway remodeling in asthmatic rats].

OBJECTIVE: To observe the effect and mechanism of ligustrazine on the airway remodeling. METHODS: Thirty-two SD rats were randomly divided into 4 groups: the normal group (A), the model group (B), the ligustrazine low-dose group (C, 40 mg/kg) and the ligustrazine high-dose group (D, 80 mg/kg), with 8 rats in each group. The chronic asthmatic model was established by repeated inhalation of ovalbumin. The changes of collagen and transforming growth factor-beta(1) (TGF-beta(1)) contents in the airway wall, the thickness of smooth muscle and basement membrane, inner and outer diameter were measured by the computerized image analysis system. RESULTS: The thickness of smooth muscle and basement membrane were (11.3 +/- 1.3, 11.3 +/- 1.7) microm in D group, (19.7 +/- 1.8, 19.8 +/- 1.6) microm in B group, the difference being significant (P < 0.01), as compared with A group [(10.6 +/- 1.2) microm, (9.8 +/- 1.6) microm] and C group [(11.6 +/- 0.9) microm, (12.3 +/- 1.8) microm], the difference being not significant (all P > 0.05). The difference in the ratio of inner diameter to outer diameter was significant between D group (0.77 +/- 0.06) and B group (0.63 +/- 0.05), P < 0.01. The contents of collagen type III and TGF-beta(1) were (21 +/- 5, 26 +/- 5) in D group, (55 +/- 7, 69 +/- 14) in B group, the difference being significant (P < 0.01). The differences were also significant when C group [32 +/- 8, 38 +/- 10] was compared with D group (P < 0.05) and B group (P < 0.01). The contents of collagen type I showed no difference among the 4 groups (A group: 34 +/- 13, B group: 44 +/- 8, C group: 36 +/- 8, D group: 39 +/- 8; all P > 0.05). A close correlation between TGF-beta(1) and collagen type III was demonstrated (r = 0.844 2, P < 0.01). CONCLUSION: Ligustrazine might suppress airway remodeling by decreasing the expression of TGF-beta(1) and reducing deposition of collagen.

Folate-polyethylene glycol conjugated carboxymethyl chitosan for tumor-targeted delivery of 5-fluorouracil.

Targeted drug delivery has been evolving at an increasing rate due to its potential to reduce the minimum effective dose of a drug and its accompanying side effects. It has shown improved therapeutic efficacy at equivalent plasma concentrations; however, the development of effective targeted delivery systems has remained a major task. In this study, a drug carrier was designed and synthesized by conjugation of folate acid (FA) to carboxymethyl chitosan (CMCS) through a polyethylene glycol (PEG) spacer. The resulting conjugates were confirmed by 1H nuclear magnetic resonance and infrared spectroscopy. The cytotoxicity of CMCS and CMCS­5­fluorouracil (5­FU) was determined by a crystal violet stain assay. The potential of CMCS­PEG­FA for use in the targeted delivery of 5­FU was investigated using 3­(4,5­dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide analysis in two cell lines, HeLa and A549, which contain different numbers of folate receptors on their surfaces. The MTT results revealed that in HeLa cells, the cytotoxicity of (CMCS­5­FU)­PEG­FU cells is greater compared with CMCS­5­FU, suggesting that folate receptor­mediated endocytosis may affect the cellular uptake efficiency of 5­FU­loaded CMCS­PEG­FA. The CMCS­PEG­FA conjugates presented in this study show promise as carriers for chemotherapeutic agents due to their solubility at physiological pH, efficiency in carrying chemotherapeutic agents, low cytotoxicity and targeting ability.