A modified experimental model of malignant pleural disease induced by lung Lewis carcinoma (LLC) cells

Cell-Derived Allograft Models as a Solution to the Obstacles of Preclinical Studies under Limited Resources: A Systematic Review on Experimental Lung Cancer Animal Models

BACKGROUND

The use of appropriate animal models for cancer studies is a major challenge, particularly for investigators who lack the resources to maintain and use xenograft animals or genetically engineered mouse models (GEMM). In addition, several countries intending to incorporate these models must conduct importation procedures, posing an additional challenge.

OBJECTIVE

This review aimed to explore the use of cell-derived allograft or syngeneic models under limited resources. The results can be used by investigators, specifically from low-middle-income countries, to contribute to lung cancer eradication.

METHODS

A literature search was carried out on various databases, including PubMed, Web of Science, and Scopus. In addition, the publication year of the selected articles was set between 2013 and 2023 with different search components (SC), namely lung cancer (SC1), animal models (SC2), and preclinical studies (SC3).

RESULTS

This systematic review focused on selecting animals, cells, and methods that could be applied to generating allograft-type lung cancer animal models from 101 included articles.

CONCLUSION

Based on the results, the use of cell-derived allograft models in cancer studies is feasible and relevant, and it provides valuable insights regarding the conditions with limited resources.

Engineered lactococcus lactis intrapleural therapy promotes regression of malignant pleural effusion by enhancing antitumor immunity

Intrapleural immunotherapies have emerged as a prominent field in treating malignant pleural effusion (MPE). Among these, bacteria-based intrapleural therapy has exerted an anti-MPE effect by immuno-stimulating or cytotoxic properties. We previously engineered a probiotic Lactococcus lactis (FOLactis) expressing a fusion protein of Fms-like tyrosine kinase 3 and co-stimulator OX40 ligands. FOLactis activates tumor antigen-specific immune responses and displays systemic antitumor efficacy via intratumoral delivery. However, no available lesions exist in the pleural cavity of patients with MPE for intratumoral administration. Therefore, we further optimize FOLactis to treat MPE through intrapleural injection. Intrapleural administration of FOLactis (I-Pl FOLactis) not only distinctly suppresses MPE and pleural tumor nodules, but also significantly extends noticeable survival in MPE-bearing murine models. The proportion of CD103+ dendritic cells (DCs) in tumor-draining lymph nodes increases three-fold in FOLactis group, compared to the wild-type bacteria group. The enhanced DCs recruitment promotes the infiltration of effector memory T and CD8+ T cells, as well as the activation of NK cells and the polarization of macrophages to M1. Programmed death 1 blockade antibody combination further enhances the antitumor efficacy of I-Pl FOLactis. In summary, we first develop an innovative intrapleural strategy based on FOLactis, exhibiting remarkable efficacy and favorable biosafety profiles. These findings suggest prospective clinical translation of engineered probiotics for managing MPE through direct administration into the pleural cavity.

Comparison of a Minimally Invasive Transthoracic Approach and a Surgical Method For Intrapleural Injection of Tumor Cells in Mice

Intrapleural injections can be used in mice to deliver therapeutic and diagnostic agents and to model human disease processes (for example, pleural fluid accumulation, malignant pleural disease, and lung cancers). In the context of establishing cancer models, minimally invasive methods of intrapleural injection are desirable because inflammation at the injection site can have a major impact on tumor growth and progression. Common approaches for intrapleural injection include surgical exposure of the thoracic wall or the diaphragm prior to injection; however, these invasive procedures require tissue dissection that triggers an undesirable inflammatory response and increases the risk of pneumothorax. While nonsurgical procedures can minimize this concern, 'blind' injections may lead to off-target inoculation. In this study, we hypothesized that a minimally invasive transthoracic approach (MI-TT) would produce a tumor distribution and burden similar to that of a surgical transabdominal approach (SX-TA). Prior to performing the procedures on live mice, surgeons were trained using cadavers and terminal procedures. Then a total of 14 nude mice (female, 4 to 6 wk old) were injected with 50 μL (5 million) A549-Luc2 human cancer cells either using the MI-TT (n = 8) or SX-TA (n = 6) approach under carprofen analgesia and isoflurane anesthesia. Our results indicate that with training, a minimally invasive transthoracic approach for intrapleural injection provides more consistent tumor placement and a greater tumor burden than does the surgical method. However, additional studies are necessary to confirm anatomic placement and characterize tumor profiles.

Treatment of malignant pleural effusion in non-small cell lung cancer with VEGF-directed therapy

BACKGROUND

Vascular endothelial growth factor (VEGF) is a critical regulator of malignant pleural effusion (MPE) in non-small-cell lung cancer (NSCLC). Bevacizumab (BEV) and apatinib (APA) are novel VEGF blockers that inhibit lung cancer cell proliferation and the development of pleural effusion.

METHODS

In this study, we established Lewis lung cancer (LLC) xenograft mouse models to compare the therapeutic effect of APA and BEV in combination with cisplatin (CDDP) against MPE. The anti-tumour and anti-angiogenic effects of this combination therapy were evaluated by ¹⁸F-FDG PET/CT imaging, TUNEL assay and Immunohistochemistry.

RESULTS

The triple drug combination significantly prolonged the overall survival of the tumour-bearing mice by reducing MPE and glucose metabolism and was more effective in lowering VEGF/soluble VEGFR-2 levels in the serum and pleural exudates compared to either of the monotherapies. Furthermore, CDDP + APA + BEV promoted in vivo apoptosis and decreased microvessel density.

CONCLUSIONS

Mechanistically, LLC-induced MPE was inhibited by targeting the VEGF-MEK/ERK pathways. Further studies are needed to establish the synergistic therapeutic effect of these drugs in NSCLC patients with MPE.KEY MESSAGESCombined treatment of MPE with apatinib, bevacizumab and cisplatin can prolong the survival time of mice, reduce the content of MPE, decrease the SUV_max of thoracic tumour tissue, down-regulate the content of VEGF and sVEGFR-2 in serum and pleural fluid, and promote the apoptosis of tumour cells. Angiogenesis and MPE formation can be inhibited by down-regulation of HIF-1α, VEGF, VEGFR-2, MEK1 and MMP-2 molecular signalling pathway proteins.

Intrapleural interleukin-2-expressing oncolytic virotherapy enhances acute antitumor effects and T-cell receptor diversity in malignant pleural disease

OBJECTIVE

The mainstay of treatment for patients with malignant pleural disease is fluid drainage and systemic therapy. A tumor-specific oncolytic virus or T-cell-activating interleukin-2 immunotherapy may provide an opportunity for local control. We previously developed a vaccinia virus-expressing interleukin-2, an oncolytic virus that mediated tumor regression in preclinical peritoneal tumor models with expansion of tumor-infiltrating lymphocytes. We evaluated the antitumor efficacy and immune modulatory effects of vaccinia virus-expressing interleukin-2 in malignant pleural disease.

METHODS

A murine model of malignant pleural disease was established with percutaneous intrapleural deposition of the Lewis lung carcinoma cell line and monitored with bioluminescent imaging. After intrapleural or systemic administration of vaccinia viruses (vaccinia virus yellow fluorescent protein control, vaccinia virus-expressing interleukin-2), systemic anti-programmed cell death-1 antibody, or combination therapy (vaccinia virus-expressing interleukin-2 and anti-programmed cell death-1), tumor mass, immune cell infiltration, T-cell receptor diversity, and survival were assessed.

RESULTS

Intrapleural vaccinia virus resulted in significant tumor regression compared with phosphate-buffered saline control (P < .05). Inclusion of the interleukin-2 transgene further increased intratumoral CD8+ T cells (P < .01) and programmed cell death-1 expression on CD8+ tumor-infiltrating lymphocytes (P < .001). Intrapleural vaccinia virus-expressing interleukin-2 was superior to systemic vaccinia virus-expressing interleukin-2, with reduced tumor burden (P < .0001) and improved survival (P < .05). Intrapleural vaccinia virus-expressing interleukin-2 alone or combined treatment with systemic anti-programmed cell death-1 reduced tumor burden (P < .01), improved survival (P < .01), and increased intratumoral αβ T-cell receptor diversity (P < .05) compared with systemic anti-programmed cell death-1 monotherapy.

CONCLUSIONS

Intrapleural vaccinia virus-expressing interleukin-2 reduced tumor burden and enhanced survival in a murine malignant pleural disease model. Increased CD8+ tumor-infiltrating lymphocytes and αβ T-cell receptor diversity are associated with enhanced response. Clinical trials will enable assessment of intrapleural vaccinia virus-expressing interleukin-2 therapy in patients with malignant pleural disease.

Influence of the progression of pleural neoplasia on the outcome of pleurodesis in mice

Purpose: Experimental study aimed at evaluating whether pleural neoplastic disease is associated with the degree of pleural fibrosis over time caused by talc pleurodesis. The study describes changes in levels of inflammatory mediators and determines whether the course of time involved in progression of neoplastic pleural disease is the factor that influences safety of talc pleurodesis usage in mice.

Materials and Methods: Animals were randomized into two groups: Cancer group (CG) that received intrapleural injection of Lewis cells or Saline group (SG) that received saline injection. After, the animals were subdivided into Early (pleurodesis 3 days after pleural injection) and Late (pleurodesis 7 days after pleural injection) groups. Half of the animals in each group were euthanized 24 hours after pleurodesis (to obtain the inflammatory data); the remaining animals were killed after 8 days (to obtain the scores of pleural fibrosis).

Results: CGs had lower fibrosis scores than SGs comparing early phases to late phases. Inflammation scores were lower in CGs, particularly in Late group. In SGs the inflammation was intense in 100% of the animals.

In Late CG group pleural adhesions had the lowest scores; we found intense fibrosis only in SGs. VEGF and LDH levels had increased in animals with cancer, particularly in Late group. Systemic distribution of talc occurred only in Late CG.

Conclusions: The time for pleural neoplasia to evolve is inversely proportional to the degree of pleural fibrosis. Earlier pleurodesis yielded the best results related to fibrosis, with less systemic inflammation and is safer in mice.

Chinese medicine Xiaoshui decoction inhibits malignant pleural effusion in mice and mediates tumor-associated macrophage polarization by activating autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoshui decoction (XSD) is a traditional Chinese medicine compound prescription that has been shown to reinforce the spleen and remove the fluid retention, while being widely used in the treatment of malignant pleural effusion (MPE). We previously reported that XSD alleviates symptoms and improves the quality of life in patients with MPE; however, the mechanism employed by XSD on MPE has not yet been elucidated.

AIM OF THE STUDY

To investigate the role and mechanism of XSD in inhibiting the development of MPE, and in regulating macrophage polarization in vitro and in vivo.

MATERIALS AND METHODS

A murine MPE model was used to study the effect of XSD on MPE. Mice with MPE were randomly allocated to a control group and XSD-low-dose (1.144 g/mL), XSD-middle-dose (2.288 g/mL), XSD-high-dose (4.576 g/mL), or cisplatin groups. RAW264.7 cells were induced to form tumor-associated macrophages (TAMs) as well as M1 and M2 macrophages using different conditioned media in vitro.

RESULTS

XSD effectively inhibited MPE formation, reduced pleural permeability and angiogenesis, and prolonged mice survival. Particularly, XSD treatment induced the polarization of TAMs to the M1 phenotype in MPE. Moreover, in-vitro XSD remarkably promoted the expansion of M1 macrophages and reduced M2 macrophages by enhancing autophagy.

CONCLUSIONS

XSD inhibits MPE development and regulates macrophage polarization by activating autophagy, indicating that XSD may serve as a novel option for integrative MPE therapies.

An improved method of delivering a sclerosing agent for the treatment of malignant pleural effusion

Background

Malignant pleural effusion (MPE) is a devastating sequela associated with cancer. Talc pleurodesis is a common treatment strategy for MPE but has been estimated to be unsuccessful in up to 20–50% of patients. Clinical failure of talc pleurodesis is thought to be due to poor dispersion. This monograph reports the development of a foam delivery system designed to more effectively coat the pleural cavity.

Methods

C57BL/6 mice were injected with Lewis lung carcinoma (LL/2) cells intrapleurally to induce MPE. The mice then received either normal saline (NS) control, foam control (F), talc slurry (TS, 2 mg/g) or talc foam (TF, 2 mg/g). Airspace volume was evaluated by CT, lungs/pleura were collected, and percent fibrosis was determined.

Results

The TF group had significantly better survival than the TS group (21 vs 13.5 days, p < 0.0001). The average effusion volume was less in the talc groups compared to the control group (140 vs 628 μL, p < 0.001). TF induced significant lung fibrosis (p < 0.01), similar to TS. On CT, TF significantly (p < 0.05) reduced loss of right lung volume (by 30–40%) compared to the control group. This was not seen with TS (p > 0.05).

Conclusions

This report describes using a novel talc foam delivery system for the treatment of MPE. In the LL/2 model, mice treated with the TF had better survival outcomes and less reduction of lung volume than mice treated with the standard of care TS. These data provide support for translational efforts to move talc foam from animal models into clinical trials.

Intrapleural targeted therapies (anti-VEGF and anti-EGFR) in the model of malignant pleural effusion

Rationale

Malignant pleural effusion has few options of treatment and drugs administrated by different routes can lead to a less permissive microenvironment for the development of malignant pleural disease.

Objectives

To analyze therapies administered intrapleurally in malignant pleural disease and to study EGFR and KRAS mutations in adenocarcinoma.

Methods

Mice received LLC cells and were treated intrapleurally with anti-VEGF, anti-EGFR, anti-VEGF+anti-EGFR or saline. Animal survival, weight and mobility, volume, biochemistry and immunology of fluid, gene expression, KRAS and EGFR mutation were evaluated.

Results

All animals developed malignant effusion and presented progressive weight loss without difference between groups; however, groups treated with anti-EGFR were more active. No difference in mortality was observed. Temporal increase of volume and inflammatory markers was observed mainly in the untreated group. Gene expression in tumors was overexpressed in VEGF, EGFR and KRAS compared with normal tissue. Mutation in exon 2 of the KRAS gene was observed.

Conclusions

Intrapleural Anti-VEGF and/or anti-EGFR reduced volume and inflammatory mediators in pleural fluid. Anti-EGFR and anti-VEGF+anti-EGFR decreased morbidity although without impact on survival. LLC tumors presented KRAS mutation, this could have influenced the action of these therapies.