KRAS mutation in intrahepatic cholangiocarcinoma: Linkage with metastasis-free survival and reduced E-cadherin expression

Synthetic approaches and clinical application of KRAS inhibitors for cancer therapy

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are among the most common oncogenic alterations in various cancers, including pancreatic, colorectal, and non-small cell lung cancer (NSCLC). Targeting KRAS has long been considered a difficult challenge due to its high affinity for guanosine triphosphate (GTP) and the lack of a druggable binding site. However, recent advancements in small-molecule inhibitor design have led to the development of targeted therapies aimed at KRAS mutations, particularly the KRASG12C mutation. Inhibitors such as Sotorasib and Adagrasib have shown promise in preclinical and clinical studies by irreversibly binding to the mutant KRAS protein, locking it in an inactive state and disrupting downstream signaling pathways critical for tumor growth and survival. These inhibitors have demonstrated clinical efficacy in treating patients with KRASG12C-mutated cancers, leading to tumor regression, prolonged progression-free survival, and improved patient outcomes. This review discusses the synthetic strategies employed to develop these KRAS inhibitor and also examines the clinical application of these inhibitors, highlighting the challenges and successes encountered during clinical trials. Ultimately, KRAS inhibitors represent a breakthrough in cancer therapy, offering a promising new treatment option for patients with KRAS-driven tumors.

Molecular signatures of intrahepatic cholangiocarcinoma: role in targeted therapy selection

Cholangiocarcinoma is a highly lethal disease with a 5-year overall survival rate of 7-20%. A minority of patients present with resectable disease, and relapse rates remain high. Emerging data from next generation sequencing analysis have identified various actionable mutations which drive the different disease courses opening door to precision medicine and targeted therapies. This review focuses on the clinical significance of genetic alterations as well as the role of systemic therapies, immunotherapy and targeted therapies for intrahepatic cholangiocarcinoma.

Mutant KRAS and CK2 Cooperatively Stimulate SLC16A3 Activity to Drive Intrahepatic Cholangiocarcinoma Progression

Intrahepatic cholangiocarcinoma (iCCA) is a lethal malignancy affecting the liver and biliary system. Enhanced understanding of the pathogenic mechanisms underlying iCCA tumorigenesis and the discovery of appropriate therapeutic targets are imperative to improve patient outcomes. In this study, we investigated the functions and regulations of solute carrier family 16 member 3 (SLC16A3), which has been reported to be a biomarker of poor prognosis in iCCA. High SLC16A3 expression was enriched in KRAS viral oncogene homolog-mutated iCCA tumors, and mutant KRAS elevated SLC16A3 expression via the PI3K-AKT-mTORC1-HIF1α pathway. SLC16A3 not only enhanced glycolysis but also induced epigenetic reprogramming to regulate iCCA progression. Phosphorylation of SLC16A3 at S436 was vital for its oncogenic function and was linked to iCCA progression. Casein kinase 2 (CK2) directly phosphorylated SLC16A3 at S436, and CK2 inhibition with CX-4945 (silmitasertib) reduced the growth of KRAS-mutated iCCA tumor xenografts and patient-derived organoids. Together, this study provides valuable insights into the diverse functions of SLC16A3 in iCCA and comprehensively elucidates the upstream regulatory mechanisms, providing potential therapeutic strategies for patients with iCCA with KRAS mutations. Significance: Characterization of the oncogenic function and regulators of SLC16A3 in intrahepatic cholangiocarcinogenesis revealed the potential of CK2 inhibitors as a promising treatment for KRAS-mutated tumors.

Recent progress in emerging molecular targeted therapies for intrahepatic cholangiocarcinoma

Cholangiocarcinoma (CCA) is a diverse group of epithelial malignant tumors arising from the biliary tract, characterized by high molecular heterogeneity. It is classified into intrahepatic (iCCA) and extrahepatic CCA (eCCA) based on the location of the primary tumor. CCA accounts for approximately 15% of all primary liver cancers, with iCCA comprising 10-20% of all CCAs. iCCA is especially known for its characteristic aggressiveness and refractoriness, leading to poor prognosis. Despite the increasing global incidence and mortality rates, surgery remains the only available standard treatment approach for a subset (25%) of patients with early-stage, resectable iCCA. The paucity of effective systemic medical therapies restricts therapeutic options for patients with advanced or metastatic iCCA. In the past decade, advances in the understanding of the molecular complexity of these tumors have provided fruitful insights for the identification of promising new druggable targets and the development of feasible therapeutic strategies that may improve treatment outcomes for patients with iCCA. In this review, we aim to highlight critical up-to-date studies and medicinal chemistry aspects, focusing on novel targeted approaches utilizing promising candidates for molecular targeted therapy in iCCA. These candidates include aberrations in isocitrate dehydrogenase (IDH) 1/2, fibroblast growth factor receptor (FGFR), B-Raf proto-oncogene (BRAF), neurotrophic tyrosine receptor kinase (NTRK), human epidermal growth factor receptor 2 (HER2), and programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1). Furthermore, this review provides an overview of potential inhibitors aimed at overcoming acquired drug resistance in these actionable targets for iCCA.

IL-21 and IL-33 May Be Effective Biomarkers to Predict the Efficacy of PD-1 Monoclonal Antibody for Advanced Cholangiocarcinoma

Background and Objective: Treatment options for patients with advanced biliary tract cancer (BTC) are limited. The programmed cell death protein-1 (PD-1) inhibitors may have synergistic effects with chemotherapy. Therefore, the aim of our study was to provide real-world data on treatment outcomes in BTC patients receiving chemotherapy alone versus a combination of chemotherapy and PD-1 inhibitors. Additionally, we explored potential markers predictive of PD-1 inhibitor efficacy in this combined therapy. Methods: We conducted a review of patients at Changzhou First People's Hospital who received PD-1 inhibitors in combination with chemotherapy or chemotherapy alone as first-line treatment for advanced BTC. The primary endpoints of the study were progression-free survival (PFS) and overall survival (OS). Kaplan-Meier survival curves and the log-rank test were used to analyze the data. Immunohistochemistry showed the expression of interleukin-21 (IL-21), interleukin-33 (IL-33), and Eomes in the tumor tissue of patients who received PD-1 inhibitors in combination with chemotherapy. Results: The study enrolled 61 patients receiving PD-1 inhibitors combined with chemotherapy and 65 receiving chemotherapy alone. The median OS and PFS for patients receiving PD-1 inhibitors in combination with chemotherapy were 11.7 and 6.7 months, respectively. These durations were significantly longer than those for chemotherapy alone: OS of 10.3 months (95% CI: 0.16-0.21, p = 0.031) and PFS of 5.3 months (95% Confidence interval (CI) 0.25-0.32, p = 0.018). High IL-21 expression or low IL-33 expression in tumor tissue correlated with better response rates to chemotherapy combined with PD-1 inhibitors. Conclusions: Combining PD-1 inhibitors with chemotherapy shows good antitumor activity, making it an effective way to treat BTC. The expression profiles of IL-21 and IL-33 hold promise as potential markers for guiding the chemotherapy combined with immunotherapy in BTC patients.

RAS signaling in carcinogenesis, cancer therapy and resistance mechanisms

Variants in the RAS family (HRAS, NRAS and KRAS) are among the most common mutations found in cancer. About 19% patients with cancer harbor RAS mutations, which are typically associated with poor clinical outcomes. Over the past four decades, KRAS has long been considered an undruggable target due to the absence of suitable small-molecule binding sites within its mutant isoforms. However, recent advancements in drug design have made RAS-targeting therapies viable, particularly with the approval of direct KRASG12C inhibitors, such as sotorasib and adagrasib, for treating non-small cell lung cancer (NSCLC) with KRASG12C mutations. Other KRAS-mutant inhibitors targeting KRASG12D are currently being developed for use in the clinic, particularly for treating highly refractory malignancies like pancreatic cancer. Herein, we provide an overview of RAS signaling, further detailing the roles of the RAS signaling pathway in carcinogenesis. This includes a summary of RAS mutations in human cancers and an emphasis on therapeutic approaches, as well as de novo, acquired, and adaptive resistance in various malignancies.

Integrative multi-omics analysis reveals the role of tumor-associated endothelial cells and their signature in prognosis of intrahepatic cholangiocarcinoma

This study aims to investigate the interplay between tumor-associated endothelial cells (TECs) and immune cells within the tumor microenvironment (TME) and its impact on tumor prognosis. We conducted single-cell RNA sequencing (scRNA-seq) of tumor, normal, and lymph node tissues obtained from intrahepatic cholangiocarcinoma (ICC) patients to reveal the role of TECs in tumor angiogenesis and their significant heterogeneity. Meanwhile, we identified genes highly expressed in TECs and constructed TEC signatures (TEC.Sig). Next, we calculated TEC scores of samples based on TEC.Sig. Patients with higher TEC scores exhibited a higher frequency of KRAS mutations, which was associated with increased infiltration of neutrophils and immature dendritic cells (iDCs), and decreased numbers of natural killer (NK), CD4 + T, and CD8 + T effector memory (Tem) cells, indicating an inflammation-dominated immunosuppressive phenotype. In contrast, BAP1 mutations and CXCL12 overexpression showed a contrasting trend. Spatial transcriptomics analysis and histological experiments further confirmed that TECs interacted with various tumor-killing immune cells through the CXCL12/CXCR4 axis. Multiple tumor immunotherapy datasets confirmed that the TEC.Sig could predict patient responses to immunotherapy. The TEC score is a promising and reliable biomarker for predicting genetic mutations and prognosis in ICC patients. Enhancing the regulation of the CXCL12/CXCR4 signaling pathway may represent a potential novel therapeutic target for ICC treatment.

Targeting KRAS-Mutated Gastrointestinal Malignancies with Small-Molecule Inhibitors: A New Generation of Breakthrough Therapies

Kirsten rat sarcoma virus (KRAS) is one of the most important and frequently mutated oncogenes in cancer and the mutational prevalence is especially high in many gastrointestinal malignancies, including colorectal cancer and pancreatic ductal adenocarcinoma. The KRAS protein is a small GTPase that functions as an "on/off" switch to activate downstream signaling, mainly through the mitogen-activated protein kinase pathway. KRAS was previously considered undruggable because of biochemical constraints; however, recent breakthroughs have enabled the development of small-molecule inhibitors of KRAS G12C. These drugs were initially approved in lung cancer and have now shown substantial clinical activity in KRAS G12C-mutated pancreatic ductal adenocarcinoma as well as colorectal cancer when combined with anti-EGFR monoclonal antibodies. Early data are encouraging for other gastrointestinal cancers as well and many other combination strategies are being investigated. Several new KRAS G12C inhibitors and novel inhibitors of other KRAS alterations have recently entered the clinic. These molecules employ a variety of innovative mechanisms and have generated intense interest. These novel drugs are especially important as KRAS G12C is rare in gastrointestinal malignancies compared with other KRAS alterations, representing potentially groundbreaking advances. Soon, the rapidly evolving landscape of novel KRAS inhibitors may substantially shift the therapeutic landscape for gastrointestinal cancers and offer meaningful survival improvements.

Challenges in Diagnosing and Reporting Cholangiocarcinoma

Intrahepatic cholangiocarcinoma is a challenge to the practicing surgical pathologist for several reasons. It is rare in many parts of the world, and thus practical exposure may be limited. Related to the fact of its rarity is the fact that more common tumors which frequently metastasize to the liver can be morphologically indistinguishable (eg, pancreatic ductal adenocarcinoma). Immunohistochemical testing is generally non-contributory in this context. Other difficulties arise from the protean morphologic manifestations of cholangiocarcinoma (ie, small duct vs. large duct) and the existence of combined cholangiocarcinoma and hepatocellular carcinoma. These, and other issues of concern to the practicing diagnostic pathologist are discussed herein.

Tumor budding as a predictor of disease-free survival in patients with cholangiocarcinoma

Background: Tumor budding is considered a prognostic factor in several solid cancer types. However, we lack comprehensive information on the importance of tumor budding in cholangiocarcinoma. Therefore, we aimed to assess the prognostic value of tumor budding in intrahepatic and extrahepatic cholangiocarcinomas and to evaluate its correlations with other clinicopathological parameters. Methods: We monitored 219 patients who underwent surgery for intrahepatic or extrahepatic cholangiocarcinoma at the Pusan National University Hospital between 2012 and 2021. Tumor budding was evaluated using the International Tumor Budding Consensus Conference scoring system. Tumor budding was classified into low (0-4), intermediate (5-9), and high (≥10). For statistical analysis, tumor budding was divided into two groups based on the cut-off value of 10 (lower: 0-9 vs. higher: ≥10). The correlations between clinicopathological parameters were examined using the chi-square and Fisher's exact test. The prognostic values of the variables were analyzed using the log-rank test and Cox regression analysis. Results: Low, intermediate, and high tumor buddings were identified in 135 (61.6%), 63 (28.8), and 21 (9.6%), patients, respectively. Higher tumor budding was related to the presence of lymphatic invasion (p = 0.017), higher tumor grade (p = 0.001), higher N category (p = 0.034). In the univariable and multivariable analyses, higher tumor budding was associated with shorter disease-free survival in 97 (44.3%) patients who underwent R0 resection (p < 0.001 and p = 0.011). Tumor budding did not significantly correlate with disease-specific survival in entire patients. Conclusion: Tumor budding may serve as a prognostic factor for intrahepatic and extrahepatic cholangiocarcinomas treated with R0 resection.

A novel murine model of combined hepatocellular carcinoma and intrahepatic cholangiocarcinoma

Primary liver cancer (PLC) is a common gastrointestinal malignancy worldwide. While hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are two major pathologic types of PLC, combined HCC and ICC (cHCC-ICC) is a relatively rare subtype that shares both hepatocyte and cholangiocyte differentiation. However, the molecular feature of this unique tumor remains elusive because of its low incidence and lack of a suitable animal model. Herein, we generated a novel spontaneous cHCC-ICC model using a Sleeping Beauty-dependent transposon plasmid co-expressing oncogenic Myc and AKT1 and a CRISPR-Cas9 plasmid expressing single-guide RNA targeting p53 into mouse hepatocytes via in situ electroporation. The histological and transcriptional analysis confirmed that this model exhibits cHCC-ICC features and activates pathways committing cHCC-ICC formation, such as TGF-β, WNT, and NF-κB. Using this model, we further screened and identified LAMB1, a protein involved in cell adhesion and migration, as a potential therapeutic target for cHCC-ICC. In conclusion, our work presents a novel genetic cHCC-ICC model and provides new insights into cHCC-ICC.