Enhancing the Radiation Response in KRAS Mutant Colorectal Cancers Using the c-Met Inhibitor Crizotinib

Understanding the molecular mechanism responsible for developing therapeutic radiation-induced radioresistance of rectal cancer and improving the clinical outcomes of radiotherapy - A review

Rectal cancer accounts for the second highest cancer-related mortality, which is predominant in Western civilizations. The treatment for rectal cancers includes surgery, radiotherapy, chemotherapy, and immunotherapy. Radiotherapy, specifically external beam radiation therapy, is the most common way to treat rectal cancer because radiation not only limits cancer progression but also significantly reduces the risk of local recurrence. However, therapeutic radiation-induced radioresistance to rectal cancer cells and toxicity to normal tissues are major drawbacks. Therefore, understanding the mechanistic basis of developing radioresistance during and after radiation therapy would provide crucial insight to improve clinical outcomes of radiation therapy for rectal cancer patients. Studies by various groups have shown that radiotherapy-mediated changes in the tumor microenvironment play a crucial role in developing radioresistance. Therapeutic radiation-induced hypoxia and functional alterations in the stromal cells, specifically tumor-associated macrophage (TAM) and cancer-associated fibroblasts (CAF), play a crucial role in developing radioresistance. In addition, signaling pathways, such as - the PI3K/AKT pathway, Wnt/β-catenin signaling, and the hippo pathway, modulate the radiation responsiveness of cancer cells. Different radiosensitizers, such as small molecules, microRNA, nanomaterials, and natural and chemical sensitizers, are being used to increase the effectiveness of radiotherapy. This review highlights the mechanism responsible for developing radioresistance of rectal cancer following radiotherapy and potential strategies to enhance the effectiveness of radiotherapy for better management of rectal cancer.

Capmatinib is an effective treatment for MET-fusion driven pediatric high-grade glioma and synergizes with radiotherapy

BACKGROUND

Pediatric-type diffuse high-grade glioma (pHGG) is the most frequent malignant brain tumor in children and can be subclassified into multiple entities. Fusion genes activating the MET receptor tyrosine kinase often occur in infant-type hemispheric glioma (IHG) but also in other pHGG and are associated with devastating morbidity and mortality.

METHODS

To identify new treatment options, we established and characterized two novel orthotopic mouse models harboring distinct MET fusions. These included an immunocompetent, murine allograft model and patient-derived orthotopic xenografts (PDOX) from a MET-fusion IHG patient who failed conventional therapy and targeted therapy with cabozantinib. With these models, we analyzed the efficacy and pharmacokinetic properties of three MET inhibitors, capmatinib, crizotinib and cabozantinib, alone or combined with radiotherapy.

RESULTS

Capmatinib showed superior brain pharmacokinetic properties and greater in vitro and in vivo efficacy than cabozantinib or crizotinib in both models. The PDOX models recapitulated the poor efficacy of cabozantinib experienced by the patient. In contrast, capmatinib extended survival and induced long-term progression-free survival when combined with radiotherapy in two complementary mouse models. Capmatinib treatment increased radiation-induced DNA double-strand breaks and delayed their repair.

CONCLUSIONS

We comprehensively investigated the combination of MET inhibition and radiotherapy as a novel treatment option for MET-driven pHGG. Our seminal preclinical data package includes pharmacokinetic characterization, recapitulation of clinical outcomes, coinciding results from multiple complementing in vivo studies, and insights into molecular mechanism underlying increased efficacy. Taken together, we demonstrate the groundbreaking efficacy of capmatinib and radiation as a highly promising concept for future clinical trials.

Novel radiation and targeted therapy combinations for improving rectal cancer outcomes

Neoadjuvant radiotherapy (RT) is commonly used as standard treatment for rectal cancer. However, response rates are variable and survival outcomes remain poor, highlighting the need to develop new therapeutic strategies. Research is focused on identifying novel methods for sensitising rectal tumours to RT to enhance responses and improve patient outcomes. This can be achieved through harnessing tumour promoting effects of radiation or preventing development of radio-resistance in cancer cells. Many of the approaches being investigated involve targeting the recently published new dimensions of cancer hallmarks. This review article will discuss key radiation and targeted therapy combination strategies being investigated in the rectal cancer setting, with a focus on exploitation of mechanisms which target the hallmarks of cancer.

Deciphering treatment resistance in metastatic colorectal cancer: roles of drug transports, EGFR mutations, and HGF/c-MET signaling

In 2023, colorectal cancer (CRC) is the third most diagnosed malignancy and the third leading cause of cancer death worldwide. At the time of the initial visit, 20% of patients diagnosed with CRC have metastatic CRC (mCRC), and another 25% who present with localized disease will later develop metastases. Despite the improvement in response rates with various modulation strategies such as chemotherapy combined with targeted therapy, radiotherapy, and immunotherapy, the prognosis of mCRC is poor, with a 5-year survival rate of 14%, and the primary reason for treatment failure is believed to be the development of resistance to therapies. Herein, we provide an overview of the main mechanisms of resistance in mCRC and specifically highlight the role of drug transports, EGFR, and HGF/c-MET signaling pathway in mediating mCRC resistance, as well as discuss recent therapeutic approaches to reverse resistance caused by drug transports and resistance to anti-EGFR blockade caused by mutations in EGFR and alteration in HGF/c-MET signaling pathway.

Modulation of mitochondrial apoptosis by β2-adrenergic receptor blockage in colorectal cancer after radiotherapy: an in-vivo and in-vitro study

Colorectal cancer (CRC) is one of the leading causes of malignancy-related deaths worldwide. Radiotherapy is often combined with surgery to treat patients with more advanced CRC. Despite impressive initial clinical responses, radiotherapy resistance is the main reason for most treatment failures in colorectal cancer. The G protein-coupled adrenergic receptor (AR) has shown to involve in the development and radiotherapy resistance of CRC. The β2-AR blockage (ICI-118,551) can use to inhibit the progression of CRC through downregulating EGFR-Akt-ERK1/2 signaling. Since catecholamines-activated the G protein-coupled AR activation has been shown to result in radioresistant, co-treatment with both β2-AR blockage and radiation may be improved the clinical outcome of CRC. We demonstrated that selective β2-AR blockage, but not selective β1-AR blockage, significantly enhanced radiation-induced apoptosis in CRC cells with wild-type p53 in vitro. The molecular mechanism of the apoptotic pathway was possibly triggered by a change in the mitochondrial membrane permeability and release of cytosolic cytochrome C through phospho-P53 mitochondrial translocation. We also found that a P53 knockout in the HCT116 cells was correlated with reversing β2-AR blockage-mediated apoptosis induction after radiation treatment. Furthermore, the β2-AR blockage significantly inhibited CRC cell-xenograft growth in vivo. Our study suggests that β2-AR blockage may be used as adjunct agent for improving the clinical outcomes of CRC following radiotherapy by inducing apoptosis in CRC cells.

A novel GSH-activable theranostic probe containing kinase inhibitor for synergistic treatment and selective imaging of tumor cells

Theranostic probe is becoming a powerful tool for diagnosis and treatment of cancer. Although some theranostic probes have been successfully developed, there is still a great room for improvement in sensitive diagnosis and efficient treatment. Herein, we developed a novel GSH-activable theranostic probe NC-G, which uses 1,8-naphthalimide-4-sulfonamide as a fluorescence imaging group and crizotinib as a highly toxic kinase inhibitor to tumor cells. The probe not only has high sensitivity (DL = 74 nM) and specificity, but also can detect GSH sensitively in cells and zebrafish. In addition, probe NC-G can not only show more obvious fluorescence in tumor cells to achieve sensitive diagnosis of tumor cells, but also release the inhibitor crizotinib to achieve high toxicity to tumor cells. It is worth noting that the consumption of GSH can cause oxidative stress response of cells and the release of SO₂ can induce cell apoptosis during the recognition process of the probe and GSH. Thus, the synergistic effect of crizotinib, GSH depletion, and SO₂ release provides a highly effective therapeutic feature for tumor cells. Therefore, probe NC-G can serve as an excellent theranostic probe for sensitive imaging and highly effective treatment of tumor cells.

Molecular mechanisms targeting drug-resistance and metastasis in colorectal cancer: Updates and beyond

Colorectal cancer (CRC) is the third most diagnosed malignancy and a major leading cause of cancer-related deaths worldwide. Despite advances in therapeutic regimens, the number of patients presenting with metastatic CRC (mCRC) is increasing due to resistance to therapy, conferred by a small population of cancer cells, known as cancer stem cells. Targeted therapies have been highly successful in prolonging the overall survival of patients with mCRC. Agents are being developed to target key molecules involved in drug-resistance and metastasis of CRC, and these include vascular endothelial growth factor, epidermal growth factor receptor, human epidermal growth factor receptor-2, mitogen-activated extracellular signal-regulated kinase, in addition to immune checkpoints. Currently, there are several ongoing clinical trials of newly developed targeted agents, which have shown considerable clinical efficacy and have improved the prognosis of patients who do not benefit from conventional chemotherapy. In this review, we highlight recent developments in the use of existing and novel targeted agents against drug-resistant CRC and mCRC. Furthermore, we discuss limitations and challenges associated with targeted therapy and strategies to combat intrinsic and acquired resistance to these therapies, in addition to the importance of implementing better preclinical models and the application of personalized therapy based on predictive biomarkers for treatment selection.

H2S-activated fluorescent probe enables dual-channel fluorescence tracking of drug release in tumor cells

Nowadays, the selective release of therapeutic drugs into tumor cells has become an important way of tumor treatment due to the high side effects of chemotherapy drugs. As one of the gas mediators, hydrogen sulfide (H₂S) is closely related to cancer. Due to the high content of H₂S in tumor cells, it can be used as a signaling molecule that triggers the release of drugs to achieve the selective release of therapeutic drugs. In addition, dual-channel fluorescence imaging technology can be better applied to monitor the drug delivery process and distinguish the state before and after drug release, so as to better track the effect of drug therapy. Based on this, we used NBD amines (NBD-NHR) as the recognition group of H₂S and connected the tyrosine kinase inhibitor crizotinib to construct an activated dual-channel fluorescent probe CZ-NBD. After the probe enters the tumor cells, it consumes H₂S and releases crizotinib, which is highly toxic to the tumor cells. Importantly, the probe displays significant fluorescence changes in different cells, enabling not only the screening of tumor cells, but also tracking and monitoring drug release and tumor cell activity. Therefore, the construction of probe CZ-NBD provides a new strategy for drug release monitoring in tumor cells.

Resistance to targeted therapy in metastatic colorectal cancer: Current status and new developments

Colorectal cancer (CRC) is one of the most lethal and common malignancies in the world. Chemotherapy has been the conventional treatment for metastatic CRC (mCRC) patients. However, the effects of chemotherapy have been unsatisfactory. With the advent of targeted therapy, the survival of patients with CRC have been prolonged. Over the past 20 years, targeted therapy for CRC has achieved substantial progress. However, targeted therapy has the same challenge of drug resistance as chemotherapy. Consequently, exploring the resistance mechanism and finding strategies to address the resistance to targeted therapy, along with searching for novel effective regimens, is a constant challenge in the mCRC treatment, and it is also a hot research topic. In this review, we focus on the current status on resistance to existing targeted therapies in mCRC and discuss future developments.

Opportunities and challenges of targeting c-Met in the treatment of digestive tumors

At present, a large number of studies have demonstrated that c-Met generally exerts a crucial function of promoting tumor cells proliferation and differentiation in digestive system tumors. c-Met also mediates tumor progression and drug resistance by signaling interactions with other oncogenic molecules and then activating downstream pathways. Therefore, c-Met is a promising target for the treatment of digestive system tumors. Many anti-tumor therapies targeting c-Met (tyrosine kinase inhibitors, monoclonal antibodies, and adoptive immunotherapy) have been developed in treating digestive system tumors. Some drugs have been successfully applied to clinic, but most of them are defective due to their efficacy and complications. In order to promote the clinical application of targeting c-Met drugs in digestive system tumors, it is necessary to further explore the mechanism of c-Met action in digestive system tumors and optimize the anti-tumor treatment of targeting c-Met drugs. Through reading a large number of literatures, the author systematically reviewed the biological functions and molecular mechanisms of c-Met associated with tumor and summarized the current status of targeting c-Met in the treatment of digestive system tumors so as to provide new ideas for the treatment of digestive system tumors.

Resistance to anti-EGFR therapies in metastatic colorectal cancer: underlying mechanisms and reversal strategies

Cetuximab and panitumumab are monoclonal antibodies (mAbs) against epidermal growth factor receptor (EGFR) that are effective agents for metastatic colorectal cancer (mCRC). Cetuximab can prolong survival by 8.2 months in RAS wild-type (WT) mCRC patients. Unfortunately, resistance to targeted therapy impairs clinical use and efficiency. The mechanisms of resistance refer to intrinsic and extrinsic alterations of tumours. Multiple therapeutic strategies have been investigated extensively to overcome resistance to anti-EGFR mAbs. The intrinsic mechanisms include EGFR ligand overexpression, EGFR alteration, RAS/RAF/PI3K gene mutations, ERBB2/MET/IGF-1R activation, metabolic remodelling, microsatellite instability and autophagy. For intrinsic mechanisms, therapies mainly cover the following: new EGFR-targeted inhibitors, a combination of multitargeted inhibitors, and metabolic regulators. In addition, new cytotoxic drugs and small molecule compounds increase the efficiency of cetuximab. Extrinsic alterations mainly disrupt the tumour microenvironment, specifically immune cells, cancer-associated fibroblasts (CAFs) and angiogenesis. The directions include the modification or activation of immune cells and suppression of CAFs and anti-VEGFR agents. In this review, we focus on the mechanisms of resistance to anti-EGFR monoclonal antibodies (anti-EGFR mAbs) and discuss diverse approaches to reverse resistance to this therapy in hopes of identifying more mCRC treatment possibilities.

miRNA-148a Enhances the Treatment Response of Patients with Rectal Cancer to Chemoradiation and Promotes Apoptosis by Directly Targeting c-Met

Patients with locally advanced rectal cancer (LARC) who achieve a pathological complete response (pCR) to neoadjuvant chemoradiotherapy (NACRT) have an excellent prognosis, but only approximately 30% of patients achieve pCR. Therefore, identifying predictors of pCR is imperative. We employed a microRNA (miRNA) microarray to compare the miRNA profiles of patients with LARC who achieved pCR (pCR group, n = 5) with those who did not (non-pCR group, n = 5). The validation set confirmed that miRNA-148a was overexpressed in the pCR group (n = 11) compared with the non-pCR group (n = 40). Cell proliferation and clonogenic assays revealed that miRNA-148a overexpression radio-sensitized cancer cells and inhibited cellular proliferation, before and after irradiation (p < 0.01). Apoptosis assays demonstrated that miRNA-148a enhanced apoptosis before and after irradiation. Reporter assays revealed that c-Met was the direct target gene of miRNA-148a. An in vivo study indicated that miRNA-148a enhanced the irradiation-induced suppression of xenograft tumor growth (p < 0.01). miRNA-148a may be a biomarker of pCR following NACRT and can promote apoptosis and inhibit proliferation in CRC cells by directly targeting c-Met in vitro and enhancing tumor response to irradiation in vivo.

Explainable artificial intelligence in high-throughput drug repositioning for subgroup stratifications with interventionable potential

Enabling precision medicine requires developing robust patient stratification methods as well as drugs tailored to homogeneous subgroups of patients from a heterogeneous population. Developing de novo drugs is expensive and time consuming with an ultimately low FDA approval rate. These limitations make developing new drugs for a small portion of a disease population unfeasible. Therefore, drug repositioning is an essential alternative for developing new drugs for a disease subpopulation. This shows the importance of developing data-driven approaches that find druggable homogeneous subgroups within the disease population and reposition the drugs for these subgroups. In this study, we developed an explainable AI approach for patient stratification and drug repositioning. Contrast pattern mining and network analysis were used to discover homogeneous subgroups within a disease population. For each subgroup, a biomedical network analysis was done to find the drugs that are most relevant to a given subgroup of patients. The set of candidate drugs for each subgroup was ranked using an aggregated drug score assigned to each drug. The proposed method represents a human-in-the-loop framework, where medical experts use the data-driven results to generate hypotheses and obtain insights into potential therapeutic candidates for patients who belong to a subgroup. Colorectal cancer (CRC) was used as a case study. Patients' phenotypic and genotypic data was utilized with a heterogeneous knowledge base because it gives a multi-view perspective for finding new indications for drugs outside of their original use. Our analysis of the top candidate drugs for the subgroups identified by medical experts showed that most of these drugs are cancer-related, and most of them have the potential to be a CRC regimen based on studies in the literature.

Adding Adjuvants to Fluoropyrimidine-based Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: An Option Worthy of Serious Consideration

The application of fluoropyrimidine-based neoadjuvant chemoradiotherapy (Fu-nCRT) of locally advanced rectal cancer (LARC) has become a common therapeutic regimen. In order to improve the efficacy and enable more patients to benefit from this treatment, an accumulation of studies have been carried out on the auxiliary use of other drugs with Fu-nCRT. However, due to specific challenges and the potential opportunities that coexist in this field, a more reasonable approach to the mode of treatment remains to be explored. In this review, we have summarized the results of the studies on the combination of Fu-nCRT with cytotoxic drugs, anti-tumor angiogenesis, and anti-EGFR agents, as well as the status of the application of immune checkpoint inhibitors in the neoadjuvant therapy of LARC patients.

MET Inhibitors for the Treatment of Gastric Cancer: What's Their Potential?

Gastric cancer remains a disease with a dismal prognosis. Extensive efforts to find targetable disease drivers in gastric cancer were implemented to improve patient outcomes. Beyond anti-HER2 therapy, MET pathway seems to be culprit of cancer invasiveness with MET-overexpressing tumors having poorer prognosis. Tyrosine kinase inhibitors targeting the HGF/MET pathway were studied in MET-positive gastric cancer, but no substantial benefit was proven. Some patients responded in early phase trials but later developed resistance. Others failed to show any benefit at all. Etiologies of resistance may entail inappropriate patient selection with a lack of MET detection standardization, tumor alternative pathways, variable MET amplification, and genetic variation. Optimizing MET detection techniques and better understanding the MET pathway, as well as tumor bypass mechanisms, are an absolute need to devise means to overcome resistance using targeted therapy alone, or in combination with other synergistic agents to improve outcomes of patients with MET-positive GC.

Radioresistance in Glioblastoma and the Development of Radiosensitizers

Ionizing radiation is a common and effective therapeutic option for the treatment of glioblastoma (GBM). Unfortunately, some GBMs are relatively radioresistant and patients have worse outcomes after radiation treatment. The mechanisms underlying intrinsic radioresistance in GBM has been rigorously investigated over the past several years, but the complex interaction of the cellular molecules and signaling pathways involved in radioresistance remains incompletely defined. A clinically effective radiosensitizer that overcomes radioresistance has yet to be identified. In this review, we discuss the current status of radiation treatment in GBM, including advances in imaging techniques that have facilitated more accurate diagnosis, and the identified mechanisms of GBM radioresistance. In addition, we provide a summary of the candidate GBM radiosensitizers being investigated, including an update of subjects enrolled in clinical trials. Overall, this review highlights the importance of understanding the mechanisms of GBM radioresistance to facilitate the development of effective radiosensitizers.

Impact of Genomic Mutation and Timing of Y90 Radioembolization in Colorectal Liver Metastases

PURPOSE

To investigate timing of Yttrium-90 radioembolization (Y90) during treatment course, genomics, and other clinical factors as predictors of overall survival (OS) in colorectal liver metastasis (CRLM) that have progressed on at least one line of chemotherapy.

MATERIALS AND METHODS

This was a retrospective study from 2013 to 2018 of patients with CRLM and genomic analysis prior to Y90 at a multihospital tertiary referral center. OS from liver metastasis diagnosis and predictors of OS were analyzed using Kaplan-Meier estimation with log-rank and Cox regression analyses.

RESULTS

Overall, 58 patients with CRLM who progressed on at least one line of chemotherapy who had genomic analysis prior to Y90 were identified. Median OS after hepatic metastasis was 29.9 months. Of these, 16 (28%) patients received Y90 after failure of the first-line systemic chemotherapy. There was significantly prolonged OS in patients receiving Y90 immediately following failure of the first-line chemotherapy folinic acid, fluorouracil, oxaliplatin ((FOLFOX) ± bevacizumab) versus following multiple lines of chemotherapy (median OS of 46.3 vs. 26.6 months, P = 0.005). The presence of genetic mutation in tumor, MAPK pathway wild type, left-sided primary tumor, low MELD score, and non-diffuse unilobar disease were also found to be predictors prolonged survival on log-rank analysis (P's < 0.05). On multivariate analysis, receiving Y90 after failure of the first line of chemotherapy, low baseline MELD score, and baseline ECOG performance score of 0 were all found to be independent predictors of prolonged OS from the time of metastatic disease diagnosis (P's < 0.05).

CONCLUSION

In patients with CRLM, receiving Y90 after failing the first line of chemotherapy, lack of genetic mutation, low MELD score, and lower tumor burden appear to be independent predictors of prolonged OS.

LEVEL OF EVIDENCE

Level 4, case-control study.

Design, synthesis and biological evaluation of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment

A series of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment were designed, synthesized, and evaluated for their biological activity. Most compounds showed effective inhibitory activity against cancer cell lines of A549, HeLa and MCF-7. Among them, the most promising compound 40 showed excellent activity against A549, HeLa and MCF-7 cell lines with IC₅₀ values of 1.03, 1.15 and 2.59 μM, respectively, which was 2.606.95 times more active than that of Golvatinib. The structure-activity relationships (SARs) showed that the introduction of 5-methylpyridazin-3(2H)-one to "5-atom linker" and the modification of the amide with morpholine group were beneficial for enhancing the inhibitory activity of compounds. In addition, the further research on compound 40 mainly include c-Met kinase activity, concentration dependence, apoptosis (acridine orange staining), and molecular docking.

Use of an imaging station for rapid colony counting in radiobiology studies

Colony counting by eye is time consuming and subjective. Here comparison between the measurements of proliferative growth inhibition in plates of radiation-treated cells by an imaging station correlated highly significantly with counts determined by eye. This would suggest that an imaging station could be a viable alternative for colony counting for doses over 200KBq.

ARQ-197 enhances the antitumor effect of sorafenib in hepatocellular carcinoma cells via decelerating its intracellular clearance

Background

Hepatocellular carcinoma (HCC) is one of the heaviest malignant burdens in China. Molecular targeting agent, sorafenib, is the main therapeutic option for antitumor therapy of advanced HCC, but it is currently too expensive for the public and its therapeutic effect does not satisfy initial expectation. Therefore, it is important to develop more effective molecular targeted therapeutic strategies for advanced HCC.

Materials and methods

The antitumor effects of sorafenib or ARQ-197, an antagonist of c-MET (tyrosine-protein kinase Met or hepatocyte growth factor receptor), were examined by MTT or in murine tumor model. The effect of ARQ-197 on epithelial-mesenchymal transition (EMT) or multidrug resistance (MDR) was examined by quantitative real-time PCR for the expression of related genes. The clearance of sorafenib in HCC cells was detected by liquid chromatography-mass spectrometry/mass spectrometry.

Results

ARQ-197 treatment enhanced the sensitivity of HCC cells to sorafenib. Mechanistic studies indicated that ARQ-197 inhibited the expression of EMT- and MDR-related genes. Moreover, ARQ-197 treatment decelerated the clearance of sorafenib in cultured HCC cells and subcutaneous HCC tumors in nude mice.

Conclusion

In the present work, our data suggested that ARQ-197 decelerated the clearance of sorafenib in HCC cells and enhanced the antitumor effect of sorafenib.