Ribociclib enhances infigratinib-induced cancer cell differentiation and delays resistance in FGFR-driven hepatocellular carcinoma

Patient-derived xenograft model: Applications and challenges in liver cancer

ABSTRACT

Liver cancer is one of the most common malignant tumors worldwide. Currently, the available treatment methods cannot fully control its recurrence and mortality rate. Establishing appropriate animal models for liver cancer is crucial for developing new treatment technologies and strategies. The patient-derived xenograft (PDX) model preserves the tumor's microenvironment and heterogeneity, which makes it advantageous for biological research, drug evaluation, personalized medicine, and other purposes. This article reviews the development, preparation techniques, application fields, and challenges of PDX models in liver cancer, providing insights for the research and exploration of PDX models in diagnostic and therapeutic strategies of liver cancer.

Advances in hepatocellular carcinoma drug resistance models

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Surgery has been the major treatment method for HCC owing to HCC's poor sensitivity to radiotherapy and chemotherapy. However, its effectiveness is limited by postoperative tumour recurrence and metastasis. Systemic therapy is applied to eliminate postoperative residual tumour cells and improve the survival of patients with advanced HCC. Recently, the emergence of various novel targeted and immunotherapeutic drugs has significantly improved the prognosis of advanced HCC. However, targeted and immunological therapies may not always produce complete and long-lasting anti-tumour responses because of tumour heterogeneity and drug resistance. Traditional and patient-derived cell lines or animal models are used to investigate the drug resistance mechanisms of HCC and identify drugs that could reverse the resistance. This study comprehensively reviewed the established methods and applications of in-vivo and in-vitro HCC drug resistance models to further understand the resistance mechanisms in HCC treatment and provide a model basis for possible individualised therapy.

METTL3 regulates thyroid cancer differentiation and chemosensitivity by modulating PAX8

Background: Thyroid cancer (TC) is a common endocrine cancer with a favourable prognosis. However, poor patient prognosis due to TC dedifferentiation is becoming an urgent challenge. Recently, methyltransferase-like 3 (METTL3)-mediated N6 -methyladenosine (m6A) modification has been demonstrated to play an important role in the occurrence and progression of various cancers and a tumour suppressor role in TC. However, the mechanism of METTL3 in TC remains unclear. Methods: The correlation between METTL3 and prognosis in TC patients was evaluated by immunohistochemistry. Mettl3fl/flBrafV600ETPO-cre TC mouse models and RNA-seq were used to investigate the underlying molecular mechanism, which was further validated by in vitro experiments. The target gene of METTL3 was identified, and the complete m6A modification process was described. The phenomenon of low expression of METTL3 in TC was explained by identifying miRNAs that regulate METTL3. Results: We observed that METTL3 expression was negatively associated with tumour progression and poor prognosis in TC. Mechanistically, silencing METTL3 promoted the progression and dedifferentiation of papillary thyroid carcinoma (PTC) both in vivo and in vitro. Moreover, overexpressing METTL3 promoted the sensitivity of PTC and anaplastic thyroid cancer (ATC) cells to chemotherapeutic drugs and iodine-131 (131I) administration. Overall, the METTL3/PAX8/YTHDC1 axis has been revealed to play a pivotal role in repressing tumour occurrence, and is antagonized by miR-493-5p.

Immunological landscape of solid cancer: Interplay between tumor and autoimmunity

The immune system, a central player in maintaining homeostasis, emerges as a pivotal factor in the pathogenesis and progression of two seemingly disparate yet interconnected categories of diseases: autoimmunity and cancer. This chapter delves into the intricate and multifaceted role of the immune system, particularly T cells, in orchestrating responses that govern the delicate balance between immune surveillance and self-tolerance. T cells, pivotal immune system components, play a central role in both diseases. In autoimmunity, aberrant T cell activation drives damaging immune responses against normal tissues, while in cancer, T cells exhibit suppressed responses, allowing the growth of malignant tumors. Immune checkpoint receptors, example, initially explored in autoimmunity, now revolutionize cancer treatment via immune checkpoint blockade (ICB). Though effective in various tumors, ICB poses risks of immune-related adverse events (irAEs) akin to autoimmunity. This chapter underscores the importance of understanding tumor-associated antigens and their role in autoimmunity, immune checkpoint regulation, and their implications for both diseases. It also explores autoimmunity resulting from cancer immunotherapy and shared molecular pathways in solid tumors and autoimmune diseases, highlighting their interconnectedness at the molecular level. Additionally, it sheds light on common pathways and epigenetic features shared by autoimmunity and cancer, and the potential of repurposing drugs for therapeutic interventions. Delving deeper into these insights could unlock therapeutic strategies for both autoimmunity and cancer.

Integrated analysis and validation of the TRIM28-H2AX-CDK4 diagnostic model assists to predict the progression of HCC

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality in the world. However, identifying key genes that can be exploited for the effective diagnosis and management of HCC remains difficult. The study aims to examine the prognostic and diagnostic value of TRIM28-H2AX-CDK4 axis in HCC. Analysis in TCGA, GSEA and Gene expression profiling interactive analysis online tools were performed to explore the expression profiles of TRIM28, H2AX and CDK4. Data demonstrating the correlation between TRIM28 expression levels and immune infiltration states or the expression of genes associated with immune checkpoints genes were exacted from TCGA and TIMER. Genetic alteration and enrichment analysis were performed using the cBioPortal and GEPIA2 tools. Finally, the expression of these proteins in HCC was then examined and validated in an independent cohort using immunohistochemistry. TRIM28 alteration exhibited co-occurrence instead of mutual exclusivity with a large number of immune checkpoint components and tumor-infiltrating immune cells, especially B cells, were found to serve roles in patients with HCC with different TRIM28 expression levels. Higher expression levels of TRIM28, H2AX and CDK4 were associated with a poorer prognosis and recurrence in patients with HCC according to TCGA, which was validated further in an independent cohort of patients with HCC. Area under curve revealed the superior predictive power of applying this three-gene signatures in this validation cohort. The diagnostic model based on this TRIM28-H2AX-CDK4 signature is efficient and provides a novel strategy for the clinical management of HCC.

Resistance to Antiangiogenic Therapy in Hepatocellular Carcinoma: From Molecular Mechanisms to Clinical Impact

Antiangiogenic drugs were the only mainstay of advanced hepatocellular carcinoma (HCC) treatment from 2007 to 2017. However, primary or secondary resistance hampered their efficacy. Primary resistance could be due to different molecular and/or genetic characteristics of HCC and their knowledge would clarify the optimal treatment approach in each patient. Several molecular mechanisms responsible for secondary resistance have been discovered over the last few years; they represent potential targets for new specific drugs. In this light, the advent of checkpoint inhibitors (ICIs) has been a new opportunity; however, their use has highlighted other issues: the vascular normalization compared to a vessel pruning to promote the delivery of an active cancer immunotherapy and the development of resistance to immunotherapy which leads to a better selection of patients as candidates for ICIs. Nevertheless, the combination of antiangiogenic therapy plus ICIs represents an intriguing approach with high potential to improve the survival of these patients. Waiting for results from ongoing clinical trials, this review depicts the current knowledge about the resistance to antiangiogenic drugs in HCC. It could also provide updated information to clinicians focusing on the most effective combinations or sequential approaches in this regard, based on molecular mechanisms.

Cyclin-Dependent Kinase 4/6 Inhibitors: A Potential Breakthrough Therapy for Malignancies of Gastrointestinal Tract

Cancer is the leading cause of death worldwide for which effective treatments remain limited. This article aimed to critically review and discuss the potential of targeting cell cycle machineries as a vital tool for cancer treatment. Cyclin dependent kinase (CDK) 4/6 inhibitors were originally approved by the United State Food and Drug Administration (US FDA) for advanced-stage breast cancer treatment. The nearly double-prolonged survival time in patients who received CDK4/6 inhibitors are superior to the conventional chemotherapy or endocrine therapy alone and, thus, these medications have been designated a breakthrough therapy by the US FDA. The requirement of CDK4/6 in the progression of cancer cells, but probably dispensable in normal cells, makes CDK4/6 a popular target for cancer treatment. The effects of CDK4/6 inhibitors in cancer may also involve the tumor microenvironment in which the therapeutic effects are synergistically pronounced. These emerging roles, hence, prompt investigations regarding their therapeutic potential in other cancers, including gastrointestinal cancer. Many preclinical and clinical studies of CDK4/6 inhibitors in gastrointestinal cancers are underway and, as a result, several new potentials are gradually reported. Contrariwise, the primary effect of this drug group is arresting the cell cycle rather than inducing cell death. The efficacy of using CDK4/6 inhibitors as a single regimen in clinical practice is then limited. In this article, the effects of CDK4/6 inhibitors on the progression of gastrointestinal cancers, at both preclinical and clinical levels are reviewed. The future directions for research and the possibility of CDK4/6 inhibitors being "breakthrough therapy" for gastrointestinal cancers are also discussed.

Targeting protein kinases in cancer stem cells

Cancer stem cells (CSCs) are subpopulations of cancer cells within the tumor bulk that have emerged as an attractive therapeutic target for cancer therapy. Accumulating evidence has shown the critical involvement of protein kinase signaling pathways in driving tumor development, cancer relapse, metastasis, and therapeutic resistance. Given that protein kinases are druggable targets for cancer therapy, tremendous efforts are being made to target CSCs with kinase inhibitors. In this review, we summarize the current knowledge and overview of the roles of protein kinases in various signaling pathways in CSC regulation and drug resistance. Furthermore, we provide an update on the preclinical and clinical studies for the use of kinase inhibitors alone or in combination with current therapies for effective cancer therapy. Despite great premises for the use of kinase inhibitors against CSCs, further investigations are needed to evaluate their efficiencies without any adverse effects on normal stem cells.

Predictive biomarkers for systemic therapy of hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the third cancer-related cause of death worldwide. In recent years, several systemic therapy drugs including sorafenib, lenvatinib, regorafenib, cabozantinib, ramucicurab, nivilumab, and pembrolizumab have been approved by FDA for advanced HCC. However, their insufficient efficacy, toxicity, and drug resistance require clinically applicable and validated predictive biomarkers.Areas covered: Our review covers the recent advancements in the identification of proteomic/genomic/epigenomic/transcriptomic biomarkers for predicting HCC treatment efficacy with the use of multi-kinase inhibitors (MKIs), CDK4/6 inhibitors, and immune checkpoint inhibitors (ICIs). Alpha-fetoprotein, des-carboxyprothrombin, vascular endothelial growth factor, angiopoietin-2, and dysregulated MTOR, VEGFR2, c-KIT, RAF1, PDGFRβ have the potential of proteomic/genomic biomarkers for sorafenib treatment. Alanine aminotransferase, aspartate aminotransferase, and albumin-bilirubin grade can predict the efficacy of other MKIs. Rb, p16, and Ki-67, and genes involved in cell cycle regulation, CDK1-4, CCND1, CDKN1A, and CDKN2A have been proposed for CD4/6 inhibitors, while dysregulated TERT, CTNNB1, TP53 FGF19, and TP53 are found to be predictors for ICI efficacy.Expert opinion: There are still limited clinically applicable and validated predictive biomarkers to identify HCC patients who benefit from systemic therapy. Further prospective biomarker validation studies for HCC personalized systemic therapy are required.

Upregulation of the ErbB family by EZH2 in hepatocellular carcinoma confers resistance to FGFR inhibitor

PURPOSE

Hepatocellular carcinoma (HCC), the most common manifestation of liver cancer, is one of the leading causes of cancer-related mortality worldwide with limited treatment options. Infigratinib, a pan-FGFR inhibitor, has shown a potent antitumour effect in HCC. However, drug resistance is often observed in long-term treatment. In this study, we examined the potential feedback mechanism(s) leading to infigratinib and explored a combination therapy to overcome resistance in HCC.

METHODS

Patient-derived xenograft (PDX) tumours were subcutaneously implanted into SCID mice and were subsequently treated with infigratinib. Tumour growth was monitored over time, and tumour samples were subjected to immunohistochemistry and Western blotting. For drug combination studies, mice were treated with infigratinib and/or varlitinib. Gene overexpression and knockdown studies were conducted to investigate the relationship between EZH2 and ErbB activity in infigratinib resistance.

RESULTS

Infigratinib-resistant tumours exhibited higher levels of p-ErbB2 and p-ErbB3, concomitant with an increase in EZH2 expression. Gene overexpression and knockdown studies revealed that EZH2 directly regulates the levels of p-ErbB2 and p-ErbB3 in acquired resistance to infigratinib. The addition of varlitinib effectively overcame infigratinib resistance and prolonged the antitumour response, with minimal toxicity.

CONCLUSION

The upregulation of the ErbB family by EZH2 appears to contribute to infigratinib resistance. The combination of infigratinib and varlitinib showed a potent antitumour effect and did not result in additional toxicity, warranting further clinical investigation.

Shikonin Inhibits Tumor Growth of ESCC by suppressing PKM2 mediated Aerobic Glycolysis and STAT3 Phosphorylation

Background: Shikonin, a small molecule inhibitor of pyruvate kinase 2 (PKM2), has been demonstrated to play the antitumor effect in various cancers. However, the specific effects and related regulatory mechanism of Shikonin in esophageal squamous cell carcinoma (ESCC) have not been clearly declared. Materials and methods: Cell viability was valued through 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Glucose consumption, lactate production, glycolytic intermediates and pyruvate kinase enzymatic activity were measured using corresponding assay kits. Patient-derived xenograft (PDX) models were constructed to observe the anti-ESCC effect of Shikonin in vivo. PKM2, p-PKM2, signal transducer and activator of transcription 3 (STAT3), p-STAT3, glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) in ESCC tissues were assessed by western blot. The expression of PKM2, p-PKM2, p-STAT3, GLUT1 and HK2 was assessed by immunohistochemistry (IHC) in ESCC tissue based on PDXs. Results: Shikonin effectively inhibited cell proliferation in dose-dependent and time-dependent manner compared with the control group. The detection of glycolysis showed that Shikonin suppressed the glucose consumption, lactate production, glycolytic intermediates and pyruvate kinase enzymatic activity. Furthermore, Shikonin not only inhibited the growth of ESCC, but also decreased the expression of p-PKM2 and p-STAT3 in vivo. Finally, Shikonin suppressed the expression of GLUT1 and HK2 proteins which are related to glycolysis. Conclusion: Shikonin has a significant antitumor effect in the ESCC by suppressing PKM2 mediated aerobic glycolysis and regulating PKM2/STAT3 signal pathway.