mouse surgery for intrapulmonary inoculation of a549-irfp cell-derived multicellular spheroids

Intrapulmonary Inoculation of Multicellular Spheroids to Model Orthotopic NSCLC

Among all oncological disorders, lung cancer not only inflicts the highest life loss but also claims the second-highest number of new patients every year in the US1. This devastating malignancy stands as a major obstacle in modern healthcare, urging for a deeper understanding of its intricate biology and more efficacious therapeutic modalities2. Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer and tends to develop into solid tumors3. One of the foremost challenges in lung cancer is the dynamic and heterogeneous tumor microenvironment, which profoundly influences the cancer&#39;s progression and responses to therapeutic interventions4,5,6. A deeper understanding of the interplay between cancer cells and their microenvironment at different stages of NSCLC calls for refined pathological models that recapitulate the histological features of NSCLC progression.
In this regard, orthotopic animal models emerge as a promising avenue for NSCLC research. Unlike commonly employed subcutaneous xenograft models7, orthotopic models feature cancer cells that are directly inoculated into the organ of origin. For lung cancer, this means implanting cancer cells directly into the lung tissue8,9. Consequently, orthotopic models of lung cancer better mimic the native tumor microenvironment, including the neighboring tissues, vessels, and immune components, thus improving their physiological and clinical relevance.
Three-dimensional multicellular spheroids (MCS) represent another promising approach to recapitulating features of the tumor environment. Most cancers are characterized by their complex tumor microenvironment, including the various cell-cell interactions, the extracellular matrix, and the gradients in oxygen and nutrients10,11. Traditional 2D cell cultures lack the spatial and structural complexity to recapitulate these tumor-specific features12. In contrast, MCS of appropriate size feature a heterogeneous structure with a hypoxic and necrotic core, which recapitulates not only the intratumoral microenvironment but also the physiological barrier against drug penetration, which is a major mechanism of drug resistance in anticancer therapy13,14,15.
Taking advantage of both the orthotopic animal models and the MCS culturing techniques, MCS have been inoculated to immune-compromised mice to successfully construct orthotopic models of breast cancer and prostate cancer16,17. Herein, we report the detailed methodology to construct and characterize a murine orthotopic xenograft model of lung cancer. This method employs the intrapulmonary inoculation of 3D MCS derived from fluorescent human lung cancer cells (A549-iRFP)18. This model offers an exceptional opportunity to observe the in vivo progression of lung cancer through stages that closely parallel the four clinical stages of NSCLC. Furthermore, the xenograft cancer of this model responded to the clinically established antilung cancer drug, cisplatin.

Author Spotlight: Establishing a Murine Non-Small Cell Lung Cancer Model for Developing Nanoformulations of Anticancer Drugs

Construction of An Orthotopic Xenograft Model of Non-Small Cell Lung Cancer Mimicking Disease Progression and Predicting Drug Activities

Our research focused on developing nanoformulations of anticancer drugs. In order to evaluate anticancer activities, we established this murine non-small cell lung cancer model by inoculation of multicellular spheroids. We aim to validate this model's ability to replicate clinical stages, drug tumor progression, reflux imaging, and response to therapeutic treatments.We aim to establish a more clinically relevant model of non-small cell lung cancer. Traditional model using subcutaneous inoculation of 2D cell suspension lack the fidelity to a tumor microenvironment and disease progression. By utilizing multicellular spheroids and orthotopic inoculation, we bridge this gap, better mimicking non-small cell lung cancer complexity and therapy response.With this orthotopic animal model, we have opened avenues to investigate non-small cell lung cancer tumor microenvironment and screen normal molecule for anticancer activity. Our finding paved the way for deeper exploration into tumor biology and the developments of anticancer therapies.

Mouse Surgery for Intrapulmonary Inoculation of A549-iRFP Cell-Derived Multicellular Spheroids

Begin the surgical procedure on the properly anesthetized mouse by injecting buprenorphine hydrochloride subcutaneously to reduce the pain. Apply ophthalmic ointment to the eyes to prevent dryness. Place the mouse in a dorsal posture and secure the limbs in a stretching position with tapes.Disinfect the back skin using alternating swabs of iodine and alcohol, at least three times each. Next, using surgical scissors, cut a 0.5-to-one-centimeter incision on the left back side of the animal. Carefully use forceps to separate the muscle and fat tissues until the chest wall and lung motion are visible.Using a pipette, transfer one selected multicellular steroid, or MCS, from a microplate into a glass Petri dish containing ice-cold PBS. Attach a 20-gauge needle to a 100-microliter glass syringe and pre-cool them on ice. Then draw 20 microliters of a pre-cooled mixture of PBS and Matrigel.Use the syringe to quickly aspirate one MCS from the Petri dish in a minimum volume of PBS-Matrigel mixture, keeping the spheroid in the metal part of the needle. Gently insert the needle vertically between two rib bones to a depth of approximately three millimeters and slowly inject all 20 microliters of the mixture containing the aspirated MCS. Then carefully remove the needle.Apply triple antibiotic ointment to the wound. Seal the incision with surgical clips to be removed after two weeks. Place the animal on an infrared heat pad and cover it with laboratory wipes to maintain the body temperature.Monitor the animal for at least 30 to 60 minutes until it wakes up and moves properly. Using a small animal imaging system at a 700-nanometer channel, measure the IRFP fluorescent signal from the tumor xenograft of the anesthetized mouse every three to four days. Measure the fluorescence in four postures, left, right, dorsal and ventral.The net fluorescence intensity from both the left and ventral sides showed a similar trend of tumor progression, with fluorescence from the ventral side growing slightly slower than the fluorescence from the left side.

mouse-surgery-for-intrapulmonary-inoculation-a549-irfp-cell-derived

Research

JoVE Journal

Cancer Research

58 Views. Begin the surgical procedure on the properly anesthetized mouse by injecting buprenorphine hydrochloride subcutaneously to reduce the pain. Apply ophthalmic ointment to the eyes to prevent dryness. Place the mouse in a dorsal posture and secure the limbs in a stretching position with tapes.Disinfect the back skin using alternating swabs of iodine and alcohol, at least three times each. Next, using surgical scissors, cut a 0.5-to-one-centimeter incision on the left back side of the anim...

Video: Mouse Surgery for Intrapulmonary Inoculation of A549-iRFP Cell-Derived Multicellular Spheroids

Non-small cell lung cancer (NSCLC) is a highly lethal disease with a complex and heterogeneous tumor microenvironment. Currently, common animal models based on subcutaneous inoculation of cancer cell suspensions do not recapitulate the tumor microenvironment in NSCLC. Herein we describe a murine orthotopic lung cancer xenograft model that employs the intrapulmonary inoculation of three-dimensional multicellular spheroids (MCS). Specifically, fluorescent human NSCLC cells (A549-iRFP) were cultured in low-attachment 96-well microplates with collagen for 3 weeks to form MCS, which were then inoculated intercostally into the left lung of athymic nude mice to establish the orthotopic lung cancer model.
Compared with the original A549 cell line, MCS of the A549-iRFP cell line responded similarly to anticancer drugs. The long-wavelength fluorescent signal of the A549-iRFP cells correlated strongly with common markers of cancer cell growth, including spheroid volume, cell viability, and cellular protein level, thus allowing dynamic monitoring of the cancer growth in vivo by fluorescent imaging. After inoculation into mice, the A549-iRFP MCS xenograft reliably progressed through phases closely resembling the clinical stages of NSCLC, including the expansion of the primary tumor, the emergence of neighboring secondary tumors, and the metastases of cancer cells to the contralateral right lung and remote organs. Moreover, the model responded to the benchmark antilung cancer drug, cisplatin with the anticipated toxicity and slower cancer progression. Therefore, this murine orthotopic xenograft model of NSCLC would serve as a platform to recapitulate the disease&#39;s progression and facilitate the development of potential anticancer drugs.

This study presents an orthotopic non-small cell lung cancer (NSCLC) model based on intrapulmonary inoculation of multicellular spheroids of fluorescent A549-iRFP cells. The model recapitulates clinical NSCLC stages and responds to cisplatin, according to dynamic in vivo monitoring of long-wavelength fluorescence.

Non-small cell lung cancer (NSCLC) is a highly lethal disease with a complex and heterogeneous tumor microenvironment. Currently, common animal models ...

Establishment of 3D Multicellular Spheroids from A549-iRFP Cells for Tumor Inoculation

To begin, establish the three dimensional multicellular spheroids or MCS from human lung adenocarcinoma or A549 iRFP cells. Seed the cells in 96 well ultra-low attachment round bottom spheroid micro plate using 100 microliters of complete growth medium supplemented with 0.3%collagen. Centrifuge the micro plates at 300 G for seven minutes at four degrees Celsius to facilitate the MCS formation.After centrifugation, examine the spheroid morphology under a microscope to ensure cell aggregation. Replace 100 microliters of growth medium in each well with fresh complete growth medium every other day. While observing under a microscope, choose spheroids with a round shape and overall smooth edges, but with five to 10 rough buddings and an appropriate diameter.Measure the iRFP fluorescence to select the MCS with fluorescent signals within one standard deviation of the average.