Th17 cell function in cancers: immunosuppressive agents or anti-tumor allies?

T helper (Th) 17 cells, a distinct subset of Th lymphocytes, are known for their prominent interleukin (IL)-17 production and other pro-inflammatory cytokines. These cells exhibit remarkable plasticity, allowing them to exhibit different phenotypes in the cancer microenvironment. This adaptability enables Th17 cells to promote tumor progression by immunosuppressive activities and angiogenesis, but also mediate anti-tumor immune responses through employing immune cells in tumor setting or even by directly converting toward Th1 phenotype and producing interferon-gamma (IFN-γ). This dual role of Th17 cells in cancer makes it a double-edged sword in encountering cancer. In this review, we aim to elucidate the complexities of Th17 cell function in cancer by summarizing recent studies and, ultimately, to design novel therapeutic strategies, especially targeting Th17 cells in the tumor milieu, which could pave the way for more effective cancer treatments.

Combining energy-based focal ablation and immune checkpoint inhibitors: preclinical research and clinical trials

Energy-based focal therapy (FT) uses targeted, minimally invasive procedures to destroy tumors while preserving normal tissue and function. There is strong emerging interest in understanding how systemic immunity against the tumor can occur with cancer immunotherapy, most notably immune checkpoint inhibitors (ICI). The motivation for combining FT and ICI in cancer management relies on the synergy between the two different therapies: FT complements ICI by reducing tumor burden, increasing objective response rate, and reducing side effects of ICI; ICI supplements FT by reducing local recurrence, controlling distal metastases, and providing long-term protection. This combinatorial strategy has shown promising results in preclinical study (since 2004) and the clinical trials (since 2011). Understanding the synergy calls for understanding the physics and biology behind the two different therapies with distinctive mechanisms of action. In this review, we introduce different types of energy-based FT by covering the biophysics of tissue-energy interaction and present the immunomodulatory properties of FT. We discuss the basis of cancer immunotherapy with the emphasis on ICI. We examine the approaches researchers have been using and the results from both preclinical models and clinical trials from our exhaustive literature research. Finally, the challenges of the combinatory strategy and opportunities of future research is discussed extensively.

Combination of thermal ablation by focused ultrasound, pFAR4-IL-12 transfection and lipidic adjuvant provide a distal immune response

Aim:

Gene-based immunotherapy against cancer is limited by low gene transfer efficiency. In the literature, interleukin-12 (IL-12) encoding plasmid associated with sonoporation has been shown to enhance antitumoral activity. Moreover, non-viral carriers and high-frequency ultrasound have both been shown to promote immune response activation. Here, IL-12 encoding plasmid, non-viral carrier stimulating the immune response and focused ultrasound were combined in order to improve the antitumoral efficiency.

Methods:

In order to enhance a gene-based antitumoral immune response, home-made lipids Toll-like receptor 2 (TLR2) agonists and plasmid free of antibiotic resistance version 4 (pFAR4), a mini-plasmid, encoding the IL-12 cytokine were combined with high-intensity focused ultrasound (HIFU). The lipid composition and the combination conditions were selected following in vitro and in vivo preliminary studies. The expression of IL-12 from our plasmid construct was measured in vitro and in vivo. The combination strategy was evaluated in mice bearing colon carcinoma cells (CT26) tumors following their weight, tumor volume, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) levels in the serum and produced by splenocytes exposed to CT26 tumor cells.

Results:

Lipid-mediated cell transfection and intratumoral injection into CT26 tumor mice using pFAR4-IL-12 led to the secretion of the IL-12 cytokine into cell supernatant and mice sera, respectively. Conditions of thermal deposition using HIFU were optimized. The plasmid encoding pFAR4-IL-12 or TLR2 agonist alone had no impact on tumor growth compared with control mice, whereas the complete treatment consisting of pFAR4-IL-12, TLR2 lipid agonist, and HIFU limited tumor growth. Moreover, only the complete treatment increased significantly mice survival and provided an abscopal effect on a metastatic CT26 model.

Conclusions:

The HIFU condition was highly efficient to stop tumor growth. The combined therapy was the most efficient in terms of IL-12 and IFN-γ production and mice survival. The study showed the feasibility and the limits of this combined therapy which has the potential to be improved.

The Functional Roles of Immune Cells in Primary Liver Cancer

Primary liver cancer includes hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Incidence of liver cancer has been increasing in recent years, and the 5-year survival is <20%. HCC and CCA are often accompanied with a dense stroma coupled with infiltrated immune cells, which is referred to as the tumor microenvironment. Populations of specific immune cells, such as high density of CD163⁺ macrophages and low density of CD8⁺ T cells, are associated with prognosis and survival rates in both HCC and CCA. Immune cells in the tumor microenvironment can be a therapeutic target for liver cancer treatments. Previous studies have introduced immunotherapy using immune checkpoint inhibitors, pulsed dendritic cells, or transduced T cells, to enhance cytotoxicity of immune cells and inhibit tumor growth. This review summarizes current understanding of the roles of immune cells in primary liver cancer covering HCC and CCA.