Specific Inhibitor of Matrix Metalloproteinase Decreases Tumor Invasiveness After Radiofrequency Ablation in Liver Tumor Animal Model

Antibodies targeting ADAM17 reverse neurite outgrowth inhibition by myelin-associated inhibitors

Upon spinal cord injury, axons attempting to regenerate need to overcome the repulsive actions of myelin-associated inhibitors, including the myelin-associated glycoprotein, Nogo-A, and the oligodendrocyte myelin glycoprotein. These inhibitors bind and signal through a neuronal receptor/co-receptor/transducer complex composed of NgR1, Lingo-1, and p75. Consequently, p75 is cleaved by alpha secretase followed by gamma-secretase, triggering downstream signaling that inhibits axonal regrowth. ADAM10 and ADAM17 are both known to function as alpha secretases in neurons. Here we show that ADAM17, and not ADAM10, is the alpha secretase that recognizes and cleaves p75, when it is a part of a 5-component neuron-myelin signaling complex comprising NgR1, Lingo-1, p75, GT1b, and a myelin inhibitor. Importantly, we demonstrate the ability of inhibitory anti-ADAM17 mAbs to abrogate the cleavage of p75 in a neuroblastoma-glioma cell line and reverse the neurite outgrowth inhibition by myelin-associated inhibitors.

Fully human monoclonal antibody targeting the cysteine-rich substrate-interacting region of ADAM17 on cancer cells

ADAM17 sheds EGFR/erbB ligands and triggers oncogenic pathways that lead to the progression of solid tumors. We targeted the ADAM17 disintegrin and cysteine rich domain region (D+C) to generate a panel of single-chain antibody fragments (scFvs) that selectively bind to the D or C domains of ADAM17, but not of ADAM10 or ADAM19. From the panel, we selected one scFv, referred to as C12, based on its high binding affinity towards the target, and re-formatted it to a full IgG for further studies. High-resolution cryo-electron microscopy studies documented that the mAb binds to the ADAM17 C-domain that in ADAM proteases, notably ADAM10 and ADAM17, is known to impart substrate-specificity. The C12 mAb significantly inhibited EGFR phosphorylation in cancer cell lines by hindering the cleavage of EGFR ligands tethered to the cell surface. This inhibition provides a mechanism for potential anti-tumor effects, and indeed C12 diminished the viability of a variety of EGFR-expressing cancer cell lines. Cell-based ELISA studies revealed that C12 preferentially bound to activated ADAM17 present on tumor cells, as compared to the autoinhibited ADAM17 that is the predominant form on HEK293 and other non-tumor cells. C12 also exhibited tumor growth inhibition in an ovarian cancer xenograft mouse model. Consistent with its selective tumor cell binding in vitro, radioimmuno PET (positron emission tomography) imaging with 89Zr-DFO-C12 in mouse xenograft models confirmed tumoral accumulation of the C12 mAb.

Effect of Incomplete Cryoablation and Matrix Metalloproteinase Inhibition on Intratumoral CD8+ T-Cell Infiltration in Murine Hepatocellular Carcinoma

Background Image-guided tumor ablation is the first-line therapy for early-stage hepatocellular carcinoma (HCC), with ongoing investigations into its combination with immunotherapies. Matrix metalloproteinase (MMP) inhibition demonstrates immunomodulatory potential and reduces HCC tumor growth when combined with ablative treatment. Purpose To evaluate the effect of incomplete cryoablation with or without MMP inhibition on the local immune response in residual tumors in a murine HCC model. Materials and Methods Sixty 8- to 10-week-old female BALB/c mice underwent HCC induction with use of orthotopic implantation of syngeneic Tib-75 cells. After 7 days, mice with a single lesion were randomized into treatment groups: (a) no treatment, (b) MMP inhibitor, (c) incomplete cryoablation, and (d) incomplete cryoablation and MMP inhibitor. Macrophage and T-cell subsets were assessed in tissue samples with use of immunohistochemistry and immunofluorescence (cell averages calculated using five 1-μm2 fields of view [FOVs]). C-X-C motif chemokine receptor type 3 (CXCR3)- and interferon γ (IFNγ)-positive T cells were assessed using flow cytometry. Groups were compared using unpaired Student t tests, one-way analysis of variance with Tukey correction, and the Kruskal-Wallis test with Dunn correction. Results Mice treated with incomplete cryoablation (n = 6) showed greater infiltration of CD206+ tumor-associated macrophages (mean, 1.52 cells per FOV vs 0.64 cells per FOV; P = .03) and MMP9-expressing cells (mean, 0.89 cells per FOV vs 0.11 cells per FOV; P = .03) compared with untreated controls (n = 6). Incomplete cryoablation with MMP inhibition (n = 6) versus without (n = 6) led to greater CD8+ T-cell (mean, 15.8% vs 8.29%; P = .04), CXCR3+CD8+ T-cell (mean, 11.64% vs 8.47%; P = .004), and IFNγ+CD8+ T-cell infiltration (mean, 11.58% vs 5.18%; P = .02). Conclusion In a mouse model of HCC, incomplete cryoablation and systemic MMP inhibition showed increased cytotoxic CD8+ T-cell infiltration into the residual tumor compared with either treatment alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.

Clinical outcomes and tumor microenvironment response to radiofrequency ablation therapy: a systematic review and meta-analysis

Background

Radiofrequency ablation (RFA) utilizes minimally invasive high-energy current to precisely ablate tumor cells. It has been utilized in many cancer types including thyroid, lung, and liver cancer. It has been shown to provide adequate ablative margins with minimal complications; however, incomplete RFA may lead to recurrence of tumor. The underlying cellular mechanism and behavior of ablated cancer tissue is poorly understood.

Methods

A systematic review was performed, searching EMBASE, Web of Science, PubMed, and Scopus for studies published up to March 2022 and reported following PRISMA guidelines. Collection was performed by two groups of investigators to avoid risk of bias. The Cochrane Collaboration's tool was used for assessing risk of bias. We identified human, in vivo, and in vitro research studies utilizing RFA for tumor tissues. We required that the studies included at least one of the following: complications, recurrence, or survival, and took interest to studies identifying cellular signaling pathway patterns after RFA. Descriptive statistical analysis was performed in 'R' software including mean and confidence interval.

Results

The most frequent cancers studied were liver and lung cancers accounting for 57.4% (N=995) and 15.4% (N=267), followed by esophageal (N=190) and breast cancer (N=134). The most common reported complications were bleeding (19%) and post-operative pain (14%). In our literature search, four independent studies showed upregulation and activation of the VEGF pathway following RFA, four showed upregulation and activation of the AKT pathway following RFA, three studies demonstrated involvement of matrix metalloproteinases, and four showed upregulation of c-Met protein following RFA.

Conclusions

In our review and meta-analysis, we identify several proteins and pathways of interest of which are important in wound healing, angiogenesis, and cellular growth and survival. These proteins and pathways of interest may implicate areas of research towards RFA resistance and cancer recurrence.

The study of direct and indirect effects of radiofrequency ablation on tumor microenvironment in liver tumor animal model

BACKGROUND

Direct and indirect effects of radiofrequency ablation (RFA) on tumor microenvironment of the liver tumor have been noted, which was reported to be related to a variety of tyrosine protein kinase or cytokinetic pathway, but have not been thoroughly investigated and conclusive.

PURPOSE

To elucidate direct and indirect effects of RFA on tumor microenvironment in the liver tumor model, and to explore the role of the specific inhibitor in tumor growth by targeting the key pathway of RFA.

MATERIALS AND METHODS

One hundred and ten mice with H22 liver tumor were used in animal experiments. Eighty-four mice were randomized into three groups: control, direct RFA and indirect RFA (a block slide was inside the middle of the tumor). The growth rate of the residual tumor after RFA was calculated (n = 8 each group) and the pathologic changes at different time points (6 h, 24 h, 72 h and 7d after RFA) were evaluated (n = 5 in each subgroup). After semi-quantitative analysis of the pathological staining, the most significant marker after RFA was selected. Then, the specific inhibitor (PHA) was applied with RFA and the tumor growth and pathological changes were evaluated and compared with RFA alone. The Kruskal-Wallis test was used for evaluating the significance of different treatments in the pathological positive rate of specific markers in tumor. The two-way analysis of variance was used to determine the significance of treatment in tumor growth or body weight.

RESULTS

The growth rate of the residual tumor in the direct RFA group was faster than the indirect RFA group (P = 0.026). The pathological analysis showed the expression of HSP70 (73 ± 13% vs 27 ± 9% at 24 h, P < 0.001), SMA (70 ± 18% vs 18 ± 7% at 6 h, P < 0.001) and Ki-67 (51 ± 11% vs 33 ± 14% at 7d, P < 0.001) in the direct RFA group was higher than those in the indirect RFA group after RFA. On the other hand, the expression of c-Met (38 ± 11% vs 28 ± 9% at 24 h, P = 0.01), IL-6 (41 ± 10% vs 25 ± 9% at 24 h, P < 0.001) and HIF-α (48 ± 10% vs 28 ± 8% at 24 h, P < 0.001) in the indirect RFA group was higher than those in the direct RFA group. And the expression of c-Met increased mostly in both direct and indirect RFA group compared to the baseline (53 and 65% at 72 h). Then the specific inhibitor of c-Met-PHA was applied with RFA. The growth rate of the tumor was significantly slower in the RFA + PHA group than the RFA alone group (1112.9 ± 465.6 mm3 vs 2162.7 ± 911.1 mm3 at day 16, P = 0.02).

CONCLUSION

Direct and indirect effects of RFA on tumor microenvironment changed at different time points and resulted in increased residual tumor growth in the animal model. It can be potentially neutralized with specific inhibitor of related pathways, such as tyrosine-protein kinase c-Met.

Incomplete thermal ablation-induced up-regulation of transcription factor nuclear receptor subfamily 2, group F, member 6 (NR2F6) contributes to the rapid progression of residual liver tumor in hepatoblastoma

Hepatoblastoma is a kind of extreme malignancy frequently diagnosed in children. Although surgical resection is considered as the first-line treatment for hepatoblastoma, a relatively large population of patients have lost the preferred opportunity for surgery. Administration of locoregional ablation enables local tumor control but with the deficiency of insufficient ablation, residual tumor, and rapid progression. In this study, we integrated 219 hepatoblastoma and 121 non-cancer liver tissues to evaluate the expression of NR2F6, from which a higher NR2F6 level was found in hepatoblastoma compared with non-cancer livers with a standard mean difference (SMD) of 1.04 (95% CI: 0.79, 1.29). The overexpression of NR2F6 also appeared to be an efficient indicator in distinguishing hepatoblastoma tissues from non-cancer liver tissues from the indication of a summarized AUC of 0.90, with a pooled sensitivity of 0.76 and a pooled specificity of 0.89. Interestingly, nude mouse xenografts provided direct evidence that overexpressed NR2F6 was also detected in residual tumor compared to untreated hepatoblastoma. Chromatin immunoprecipitation-binding data in HepG2 cells and transcriptome analysis of HepG2 xenografts were combined to identify target genes regulated by NR2F6. We finally selected 150 novel target genes of NR2F6 in residual tumor of incomplete ablation, and these genes appeared to be associated with the biological regulation of lipid metabolism-related pathway. Accordingly, targeting NR2F6 holds a therapeutic promise in treating residual recurrent hepatoblastoma after incomplete ablation.