Stress Conditions Induced by Locoregional Therapies Stimulate Enrichment and Proliferation of Liver Cancer Stem Cells

Molecular mechanisms of TACE refractoriness: Directions for improvement of the TACE procedure

Transcatheter arterial chemoembolisation (TACE) is the standard of care for intermediate-stage hepatocellular carcinoma and selected patients with advanced hepatocellular carcinoma. However, TACE does not achieve a satisfactory objective response rate, and the concept of TACE refractoriness has been proposed to identify patients who do not fully benefit from TACE. Moreover, repeated TACE is necessary to obtain an optimal and sustained anti-tumour response, which may damage the patient's liver function. Therefore, studies have recently been performed to improve the effectiveness of TACE. In this review, we summarise the detailed molecular mechanisms associated with TACE responsiveness and relapse after this treatment to provide more effective targets for adjuvant therapy while helping to improve TACE regimens.

Stimulating Antitumoral Immunity by Percutaneous Cryoablation and Combination Immunoadjuvant Therapy in a Murine Model of Hepatocellular Carcinoma

PURPOSE

To test the hypothesis that antitumoral immunity can be induced after cryoablation (cryo) of hepatocellular carcinoma (HCC) through coadministration of the immunostimulant CpG and an immune checkpoint (programmed cell death 1 [PD-1]) inhibitor.

MATERIALS AND METHODS

Sixty-three immunocompetent C57BL/6J mice were generated with 2 orthotopic HCC tumor foci: 1 for treatment and 1 to observe for antitumoral immunity. Tumors were treated with incomplete cryo alone or intratumoral CpG and/or a PD-1 inhibitor. The primary endpoint was death or when the following criteria for sacrifice were met: tumor > 1 cm (determined using ultrasound) or moribund state. Antitumoral immunity was assessed using flow cytometry and histology (tumor and liver) as well as enzyme-linked immunosorbent assay (serum). Analysis of variance was used for statistical comparisons.

RESULTS

At 1 week, the nonablated satellite tumor growth was reduced by 1.9-fold (P = .047) in the cryo + CpG group and by 2.8-fold (P = .007) in the cryo + CpG + PD-1 group compared with that in the cryo group. Compared with cryo alone, the time to tumor progression to endpoints was also prolonged for cryo + CpG + PD-1 and cryo + CpG mice, with log-rank hazard ratios of 0.42 (P = .031) and 0.27 (P < .001), respectively. Flow cytometry and histology showed increased cytotoxic T-cell infiltration (P = .002) and serum levels of the proinflammatory cytokine interferon-γ (P = .015) in tumors and serum of cryo + CpG mice compared with those in tumors and serum of mice treated with cryo alone. High serum levels of the anti-inflammatory cytokine tumor growth factor-β and the proangiogenesis chemokine C-X-C motif chemokine ligand 1 were correlated with a shorter time to endpoints and faster tumor growth.

CONCLUSIONS

Cryo combined with the immunostimulant CpG promoted cytotoxic T-cell infiltration into tumors, slowed tumor growth, and prolonged the time to progression to endpoints in an aggressive murine HCC model.

Treatment of Hepatocellular Carcinoma by Multimodal In Situ Vaccination Using Cryoablation and a Plant Virus Immunostimulant

PURPOSE

To test the hypothesis that cryoablation combined with intratumoral immunomodulating nanoparticles from cowpea mosaic virus (CPMV) as an in situ vaccination approach induces systemic antitumoral immunity in a murine model of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Mice with bilateral, subcutaneous RIL-175 cell-derived HCCs were randomized to 4 groups: (a) phosphate-buffered saline (control), (b) cryoablation only (Cryo), (c) CPMV-treated only (CPMV), and (d) cryoablation plus CPMV-treated (Cryo + CPMV) (N = 11-14 per group). Intratumoral CPMV was administered every 3 days for 4 doses, with cryoablation performed on the third day. Contralateral tumors were monitored. Tumor growth and systemic chemokine/cytokine levels were measured. A subset of tumors and spleens were harvested for immunohistochemistry (IHC) and flow cytometry. One- or 2-way analysis of variance was performed for statistical comparisons. A P value of <.05 was used as the threshold for statistical significance.

RESULTS

At 2 weeks after treatment, the Cryo and CPMV groups, alone or combined, outperformed the control group in the treated tumor; however, the Cryo + CPMV group showed the strongest reduction and lowest variance (1.6-fold ± 0.9 vs 6.3-fold ± 0.5, P < .0001). For the untreated tumor, only Cryo + CPMV significantly reduced tumor growth compared with control (9.2-fold ± 0.9 vs 17.8-fold ± 2.1, P = .01). The Cryo + CPMV group exhibited a transient increase in interleukin-10 and persistently decreased CXCL1. Flow cytometry revealed natural killer cell enrichment in the untreated tumor and increased PD-1 expression in the spleen. Tumor-infiltrating lymphocytes increased in Cryo + CPMV-treated tumors by IHC.

CONCLUSIONS

Cryoablation and intratumoral CPMV, alone or combined, demonstrated potent efficacy against treated HCC tumors; however, only cryoablation combined with CPMV slowed the growth of untreated tumors, consistent with an abscopal effect.

Cancer stem cell markers for liver cancer and pancreatic cancer

Cancer stem cells (CSC) theory has ushered in a new era of cancer research. Tumor recurrence, metastasis and chemotherapy resistance are all related to the existence of cancer stem cells. Further understanding of tumor heterogeneity will contribute to targeted treatment. Liver cancer and pancreatic cancer are common digestive gland tumors with high lethality. This article reviews the identification and isolation of CSC markers in hepatocellular carcinoma and pancreatic cancer. The markers related signal pathways are involved in the occurrence and development of tumors, and have a significant impact on the proliferation, metastasis and invasion of cancer cells, which can be used as potential molecular therapeutic targets. This study will be helpful to understand cancer stem cell like cells.

Rheb regulates nuclear mTORC1 activity independent of farnesylation

The small GTPase Ras homolog enriched in brain (Rheb) plays a critical role in activating the mechanistic target of rapamycin complex 1 (mTORC1), a signaling hub that regulates various cellular functions. We recently observed nuclear mTORC1 activity, raising an intriguing question as to how Rheb, which is known to be farnesylated and localized to intracellular membranes, regulates nuclear mTORC1. In this study, we found that active Rheb is present in the nucleus and required for nuclear mTORC1 activity. We showed that inhibition of farnesyltransferase reduced cytosolic, but not nuclear, mTORC1 activity. Furthermore, a farnesylation-deficient Rheb mutant, with preferential nuclear localization and specific lysosome tethering, enables nuclear and cytosolic mTORC1 activities, respectively. These data suggest that non-farnesylated Rheb is capable of interacting with and activating mTORC1, providing mechanistic insights into the molecular functioning of Rheb as well as regulation of the recently observed, active pool of nuclear mTORC1.

Circulating Tumor Cells in Hepatocellular Carcinoma: A Comprehensive Review and Critical Appraisal

Hepatocellular carcinoma (HCC) is the fifth most common neoplasm and a major cause of cancer-related death worldwide. There is no ideal biomarker allowing early diagnosis of HCC and tumor surveillance in patients receiving therapy. Liquid biopsy, and particularly circulating tumor cells (CTCs), have emerged as a useful tool for diagnosis and monitoring therapeutic responses in different tumors. In the present manuscript, we evaluate the current evidence supporting the quantitative and qualitative assessment of CTCs as potential biomarkers of HCC, as well as technical aspects related to isolation, identification, and classification of CTCs. Although the dynamic assessment of CTCs in patients with HCC may aid the decision-making process, there are still many uncertainties and technical caveats to be solved before this methodology has a true impact on clinical practice guidelines. More studies are needed to identify the optimal combination of surface markers, to increase the efficiency of ex-vivo expansion of CTCs, or even to target CTCs as a potential therapeutic strategy to prevent HCC recurrence after surgery or to hamper tumor progression and extrahepatic spreading.

Cancer Stem Cells: A Potential Breakthrough in HCC-Targeted Therapy

Cancer stem cells (CSCs) are subpopulations of cells with stem cell characteristics that produce both cancerous and non-tumorigenic cells in tumor tissues. The literature reports that CSCs are closely related to the development of hepatocellular carcinoma (HCC) and promote the malignant features of HCC such as high invasion, drug resistance, easy recurrence, easy metastasis, and poor prognosis. This review discusses the origin, molecular, and biological features, functions, and applications of CSCs in HCC in recent years; the goal is to clarify the importance of CSCs in treatment and explore their potential value in HCC-targeted therapy.