Boosting immune responses in lung tumor immune microenvironment: A comprehensive review of strategies and adjuvants

Abstract

The immune system has a substantial impact on the growth and expansion of lung malignancies. Immune cells are encompassed by a stroma comprising an extracellular matrix (ECM) and different cells like stromal cells, which are known as the tumor immune microenvironment (TIME). TME is marked by the presence of immunosuppressive factors, which inhibit the function of immune cells and expand tumor growth. In recent years, numerous strategies and adjuvants have been developed to extend immune responses in the TIME, to improve the efficacy of immunotherapy. In this comprehensive review, we outline the present knowledge of immune evasion mechanisms in lung TIME, explain the biology of immune cells and diverse effectors on these components, and discuss various approaches for overcoming suppressive barriers. We highlight the potential of novel adjuvants, including toll-like receptor (TLR) agonists, cytokines, phytochemicals, nanocarriers, and oncolytic viruses, for enhancing immune responses in the TME. Ultimately, we provide a summary of ongoing clinical trials investigating these strategies and adjuvants in lung cancer patients. This review also provides a broad overview of the current state-of-the-art in boosting immune responses in the TIME and highlights the potential of these approaches for improving outcomes in lung cancer patients.

Graphical Abstract

Plain Language Summary

Lung cancer remains a significant global health concern, and researchers are actively exploring innovative approaches to boost the immune system’s ability to recognize and destroy cancer cells. Boosting the immune system responses against the lung tumor microenvironment is one of promising approaches for lung cancer therapy. The lung tumor microenvironment refers to the complex network of cells, proteins, and molecules that surround and support the growth of lung tumors. Unfortunately, this environment often hinders the body’s immune response, allowing cancer cells to evade detection and destruction. By comprehending the cellular and molecular factors at play, researchers can devise novel strategies to tip the balance in favor of the immune system. Cancer cells often employ various mechanisms to suppress the immune system within the lung tumor microenvironment. One approach to combating this suppression is the use of adjuvants, substances that enhance the immune response. Adjuvants can be administered alongside cancer vaccines or other immunotherapies to strengthen the immune system’s ability to recognize and attack tumor cells. The recent progresses have shown the potential of some products, adjuvants, immunotherapy drugs, vaccines, and nanoparticles. This article aims to discuss recent advancements in the field of cancer immunotherapy, specifically focusing on strategies to strengthen the body’s immune response against lung tumors.

Keywords:

• Anticancer immunity
• CD8+ T lymphocytes
• immune system
• lung cancer
• tumor immune microenvironment (TIME)

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Postdoctoral Project of Heilongjiang Province [No. LBH-Z22278]; and the Chinese Medicine Research Project of Heilongjiang Province [ZHY2023-077].