Dual VEGF inhibition with sorafenib and bevacizumab as salvage therapy in metastatic colorectal cancer: results of the phase II North Central Cancer Treatment Group study N054C (Alliance)

Targets for improving prostate tumor response to radiotherapy

Prostate cancer is a prevalent malignancy that is frequently managed with radiotherapy. However, resistance to radiotherapy remains a significant challenge in controlling this disease. Early radiotherapy is employed for locally confined prostate cancer (PCa), while recurrent disease post-surgery and metastatic castration-resistant prostate cancer (mCRPC) are treated with late-stage radiotherapy, including radium-223. Combination therapies to integrate radiotherapy and chemotherapy have demonstrated enhanced treatment efficacy. Nonetheless, both modalities can induce severe local and systemic toxicities. Consequently, selectively sensitizing prostate tumors to radiotherapy could improve therapeutic outcomes while minimizing systemic side effects. The mechanisms underlying radioresistance in prostate cancer are multifaceted, including DNA damage repair (DDR) pathways, hypoxia, angiogenesis, androgen receptor (AR) signaling, and immune evasion. The advent of 177Lu-PSMA-617, which was approved in 2022, has shown promise in targeting prostate-specific membrane antigen (PSMA) in advanced prostate cancer. Experimental and clinical studies have yielded promising results in suppressing prostate tumors by targeting these pathways. This paper reviews potential targets for sensitizing prostate tumors to radiotherapy. We discuss cellular and molecular mechanisms contributing to therapy resistance and examine findings from experimental and clinical trials on promising targets and drugs that can be used in combination with radiotherapy.

Enhancing Colorectal Cancer Immunotherapy: The Pivotal Role of Ferroptosis in Modulating the Tumor Microenvironment

Colorectal cancer (CRC) represents a significant challenge in oncology, with increasing incidence and mortality rates worldwide, particularly among younger adults. Despite advancements in treatment modalities, the urgent need for more effective therapies persists. Immunotherapy has emerged as a beacon of hope, offering the potential for improved outcomes and quality of life. This review delves into the critical interplay between ferroptosis, an iron-dependent form of regulated cell death, and immunotherapy within the CRC context. Ferroptosis's influence extends beyond tumor cell fate, reshaping the tumor microenvironment (TME) to enhance immunotherapy's efficacy. Investigations into Ferroptosis-related Genes (OFRGs) reveal their pivotal role in modulating immune cell infiltration and TME composition, closely correlating with tumor responsiveness to immunotherapy. The integration of ferroptosis inducers with immunotherapeutic strategies, particularly through novel approaches like ferrotherapy and targeted co-delivery systems, showcases promising avenues for augmenting treatment efficacy. Furthermore, the expression patterns of OFRGs offer novel prognostic tools, potentially guiding personalized and precision therapy in CRC. This review underscores the emerging paradigm of leveraging ferroptosis to bolster immunotherapy's impact, highlighting the need for further research to translate these insights into clinical advancements. Through a deeper understanding of the ferroptosis-immunotherapy nexus, new therapeutic strategies can be developed, promising enhanced efficacy and broader applicability in CRC treatment, ultimately improving patient outcomes and quality of life in the face of this formidable disease.

Regulation of VEGF-A expression and VEGF-A-targeted therapy in malignant tumors

Vascular endothelial growth factor A (VEGF-A), a highly conserved dimeric glycoprotein, is a key regulatory gene and a marker molecule of angiogenesis. The upregulation of VEGF-A facilitates the process of tumor vascularization, thereby fostering the initiation and progression of malignant neoplasms. Many genes can adjust the angiogenesis of tumors by changing the expression of VEGF-A. In addition, VEGF-A also exhibits immune regulatory properties, which directly or indirectly suppresses the antitumor activity of immune cells. The emergence of VEGF-A-targeted therapy alone or in rational combinations has revolutionized the treatment of various cancers. This review discusses how diverse mechanisms in various tumors regulate VEGF-A expression to promote tumor angiogenesis and the role of VEGF-A in tumor immune microenvironment. The application of drugs targeting VEGF-A in tumor therapy is also summarized including antibody molecule drugs and traditional Chinese medicine.

The role of stromal cells in epithelial-mesenchymal plasticity and its therapeutic potential

The epithelial-mesenchymal transition (EMT) is a critical tumor invasion and metastasis process. EMT enables tumor cells to migrate, detach from their original location, enter the circulation, circulate within it, and eventually exit from blood arteries to colonize in foreign sites, leading to the development of overt metastases, ultimately resulting in death. EMT is intimately tied to stromal cells around the tumor and is controlled by a range of cytokines secreted by stromal cells. This review summarizes recent research on stromal cell-mediated EMT in tumor invasion and metastasis. We also discuss the effects of various stromal cells on EMT induction and focus on the molecular mechanisms by which several significant stromal cells convert from foes to friends of cancer cells to fuel EMT processes via their secretions in the tumor microenvironment (TME). As a result, a better knowledge of the role of stromal cells in cancer cells' EMT may pave the path to cancer eradication.

Network neighborhood operates as a drug repositioning method for cancer treatment

Computational drug repositioning approaches are important, as they cost less compared to the traditional drug development processes. This study proposes a novel network-based drug repositioning approach, which computes similarities between disease-causing genes and drug-affected genes in a network topology to suggest candidate drugs with highest similarity scores. This new method aims to identify better treatment options by integrating systems biology approaches. It uses a protein-protein interaction network that is the main topology to compute a similarity score between candidate drugs and disease-causing genes. The disease-causing genes were mapped on this network structure. Transcriptome profiles of drug candidates were taken from the LINCS project and mapped individually on the network structure. The similarity of these two networks was calculated by different network neighborhood metrics, including Adamic-Adar, PageRank and neighborhood scoring. The proposed approach identifies the best candidates by choosing the drugs with significant similarity scores. The method was experimented on melanoma, colorectal, and prostate cancers. Several candidate drugs were predicted by applying AUC values of 0.6 or higher. Some of the predictions were approved by clinical phase trials or other in-vivo studies found in literature. The proposed drug repositioning approach would suggest better treatment options with integration of functional information between genes and transcriptome level effects of drug perturbations and diseases.

Ramucirumab combination with sorafenib enhances the inhibitory effect of sorafenib on HepG2 cancer cells

Sorafenib, an oral multiple kinase inhibitor, is the standardized treatment for hepatocellular carcinoma (HCC). One strategy to improve HCC therapy is to combine agents that target key signaling pathways. In this study we set out to investigate the effect of combining sorafenib with either bevacizumab (anti-VEGF), panitumumab (anti-EGFR) or ramucirumab (anti-VEGFR2) on HepG2 cancer cell line with the aim of improving efficacy and possibility of therapeutic dose reduction of sorafenib.: HepG2 cancer cell line was treated with sorafenib alone or in combination with either bevacizumab, panitumumab or ramucirumab. Cell proliferation; apoptosis and cell cycle distribution; gene expression of VEGFR2, EGFR, MMP-9 and CASPASE3; the protein levels of pVEGFR2 and pSTAT3 and the protein expression of CASPASE3, EGFR and VEGFR2 were determined. Combined treatments of sorafenib with ramucirumab or panitumumab resulted in a significant decrease in sorafenib IC₅₀. Sorafenib combination with ramucirumab or bevacizumab resulted in a significant arrest in pre-G and G0/G1 cell cycle phases, significantly induced apoptosis and increased the relative expression of CASPASE3 and decreased the anti-proliferative and angiogenesis markers´ MMP-9 and pVEGFR2 or VEGFR2 in HepG2 cells. A significant decrease in the levels of pSTAT3 was only detected in case of sorafenib-ramucirumab combination. The combined treatment of sorafenib with panitumumab induced a significant arrest in pre-G and G2/M cell cycle phases and significantly decreased the relative expression of EGFR and MMP-9. Sorafenib-ramucirumab combination showed enhanced apoptosis, inhibited proliferation and angiogenesis in HepG2 cancer cells. Our findings suggest that ramucirumab can be a useful as an adjunct therapy for improvement of sorafenib efficacy in suppression of HCC.

The Synergistic Cytotoxic Effects of GW5074 and Sorafenib by Impacting Mitochondrial Functions in Human Colorectal Cancer Cell Lines

Colorectal cancer (CRC) ranks third in the United States for incidence or mortality. Surgical resection is the primary treatment for patients at an early stage, while patients with advanced and metastatic CRC receive combined treatment with chemotherapy, radiotherapy, or targeted therapy. C-RAF plays a key role in maintaining clonogenic and tumorigenic capacity in CRC cells and it might be a potential therapeutic target for CRC. Sorafenib is a popular oral multi-kinase inhibitor, including a B-RAF inhibitor that targets the RAF-MEK-ERK pathway. Sorafenib, as a single agent, has tumor-suppressing efficacy, but its clinical application is limited due to many complex drug resistance mechanisms and side effects. GW5074 is one of the C-RAF inhibitors and has the potential to enhance the efficacy of existing cancer chemotherapies. In this study, we investigated whether the combination of sorafenib with GW5074 could reduce the dosage of sorafenib and enhance its tumor-suppressive effect in two CRC cell lines, HCT116 and LoVo cells. Our findings demonstrate that GW5074 can potentiate the cytotoxicity of sorafenib and dramatically reduce the half-maximal inhibitory concentration (IC50) dose of sorafenib from 17 and 31 µM to 0.14 and 0.01 µM in HCT116 and LoVo cells, respectively. GW5074, similar to sorafenib, suppressed the cellular proliferation and induced cellular apoptosis and cytosolic ROS, but had no further enhancement on the above-mentioned effects when combined with sorafenib. The synergistic effects of GW5074 and sorafenib were mainly found in mitochondrial functions, including ROS generation, membrane potential disruption, and fission–fusion dynamics, which were examined by using the flow cytometry analysis. In summary, the C-RAF inhibitor GW5074 might potentiate the cytotoxicity of the B-RAF inhibitor sorafenib mediated through mitochondrial dysfunctions, suggesting that GW5074 potentially serves as a sensitizer for sorafenib application to reduce the risk of drug resistance of CRC treatment. Our findings also provide novel insights on using C-RAF inhibitors combined with sorafenib, the current CRC therapeutic drug choice, in CRC treatment.

The Role of the Tumor Microenvironment and Treatment Strategies in Colorectal Cancer

Colorectal cancer (CRC) has the second highest mortality rate among all cancers worldwide. Surgery, chemotherapy, radiotherapy, molecular targeting and other treatment methods have significantly prolonged the survival of patients with CRC. Recently, the emergence of tumor immunotherapy represented by immune checkpoint inhibitors (ICIs) has brought new immunotherapy options for the treatment of advanced CRC. As the efficacy of ICIs is closely related to the tumor immune microenvironment (TME), it is necessary to clarify the relationship between the immune microenvironment of CRC and the efficacy of immunotherapy to ensure that the appropriate drugs are selected. We herein review the latest research progress in the immune microenvironment and strategies related to immunotherapy for CRC. We hope that this review helps in the selection of appropriate treatment strategies for CRC patients.

Cytotoxic Ruthenium(II) Complexes of Pyrazolylbenzimidazole Ligands That Inhibit VEGFR2 Phosphorylation

Eight new ruthenium(II) complexes of N,N-chelating pyrazolylbenzimidazole ligands of the general formula [Ru^II(p-cym)(L)X]⁺ [where the ligand L is 2-(1H-pyrazol-1-yl)-1H-benzo[d]imidazole (L1) substituted at the 4 position of the pyrazole ring by Cl (L2), Br (L3), or I (L4) and X = Cl^- and I^-] were synthesized and characterized using various analytical techniques. Complexes 1 and 3 were also characterized by single-crystal X-ray crystallography, and they crystallized as a monoclinic crystal system in space groups P2₁/n and P2₁/c, respectively. The complexes display good solution stability at physiological pH 7.4. The iodido-coordinated pyrazolylbenzimidazole ruthenium(II) p-cymene complexes (2, 4, 6, and 8) are more resistant toward hydrolysis and have less tendency to form monoaquated complexes in comparison to their chlorido analogues (1, 3, 5, and 7). The halido-substituted 2-(1H-pyrazol-1-yl)-1H-benzo[d]imidazole ligands, designed as organic-directing molecules, inhibit vascular endothelial growth factor receptor 2 (VEGFR2) phosphorylation. In addition, the ruthenium(II) complexes display a potential to bind to DNA bases. The cytotoxicity profile of the complexes (IC₅₀ ca. 9-12 μM for 4-8) against the triple-negative breast cancer cells (MDA-MB-231) show that most of the complexes are efficient. The lipophilicity and cellular accumulation data of the complexes show a good correlation with the cytotoxicity profile of 1-8. The representative complexes 3 and 7 demonstrate the capability of arresting the cell cycle in the G2/M phase and induce apoptosis. The inhibition of VEGFR2 phosphorylation with the representative ligands L2 and L4 and the corresponding metal complexes 3 and 7 in vitro shows that the organic-directing ligands and their complexes inhibit VEGFR2 phosphorylation. Besides, L2, L4, 3, and 7 inhibit the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and proto-oncogene tyrosine-protein kinase (Src), capable of acting downstream of VEGFR2 as well as independently. Compounds L2, L4, 3, and 7 have a lesser effect on ERK1/2 and more prominently affect Src phosphorylation. We extended the study for L2 and 3 in the Tg(fli1:gfp) zebrafish model and found that L2 is more effective in vivo compared to 3 in inhibiting angiogenesis.

Current Advances and Trends in KRAS Targeted Therapies for Colorectal Cancer

Kirsten Rat Sarcoma (KRAS) gene somatic point mutations is one of the most prominently mutated proto-oncogenes known to date, and accounts for approximately 60% of all colorectal cancer cases. One of the most exciting drug development areas against colorectal cancer is the targeting of undruggable kinases and kinase-substrate molecules, although whether and how they can be integrated with other therapies remains a question. Current clinical trial data have provided supporting evidence on the use of combination treatment involving MEK inhibitors and either one of the PI3K inhibitors for patients with metastatic colorectal cancer to avoid the development of resistance and provide effective therapeutic outcome rather than using a single agent alone. Many clinical trials are also ongoing to evaluate different combinations of these pathway inhibitors in combination with immunotherapy for patients with colorectal cancer whose current palliative treatment options are limited. Nevertheless, continued assessment of these targeted cancer therapies will eventually allow patients with colorectal cancer to be treated using a personalized medicine approach. In this review, the most recent scientific approaches and clinical trials targeting KRAS mutations directly or indirectly for the management of colorectal cancer are discussed.

Potential Molecular Cross Talk Among CCR5 Pathway Predicts Regorafenib Responsiveness in Metastatic Colorectal Cancer Patients

BACKGROUND

Genetic variants in the CCL5/CCR5 pathway have been shown to predict regorafenib efficacy in patients with metastatic colorectal cancer (mCRC). This study investigated the biological role of CCL4 and CCL3 gene polymorphisms in patients with refractory mCRC treated using regorafenib.

PATIENTS AND METHODS

We analyzed the genomic DNA extracted from mCRC patients receiving regorafenib. Serum factor levels at baseline, day 21, and progressive disease (PD) were measured using ELISA.

RESULTS

Decreased CCL4 levels at day 21 or increased CCL3 levels at PD were associated with better clinical outcomes. In patients with any CCL5 rs2280789 G allele, CCL3 significantly increased between BL and day 21 compared with the A/A variant (72.7% vs. 23.1%, p=0.006), but CCL4 decreased (31.8% vs. 69.2%, p=0.043).

CONCLUSION

Increased CCL3 and decreased CCL4 seen in specific genotypes may serve as potential biomarkers of regorafenib in mCRC patients.

Progress in Natural Compounds/siRNA Co-delivery Employing Nanovehicles for Cancer Therapy

Chemotherapy using natural compounds, such as resveratrol, curcumin, paclitaxel, docetaxel, etoposide, doxorubicin, and camptothecin, is of importance in cancer therapy because of the outstanding therapeutic activity and multitargeting capability of these compounds. However, poor solubility and bioavailability of natural compounds have limited their efficacy in cancer therapy. To circumvent this hurdle, nanocarriers have been designed to improve the antitumor activity of the aforementioned compounds. Nevertheless, cancer treatment is still a challenge, demanding novel strategies. It is well-known that a combination of natural products and gene therapy is advantageous over monotherapy. Delivery of multiple therapeutic agents/small interfering RNA (siRNA) as a potent gene-editing tool in cancer therapy can maximize the synergistic effects against tumor cells. In the present review, co-delivery of natural compounds/siRNA using nanovehicles are highlighted to provide a backdrop for future research.

Combination Antitumor Effect of Sorafenib via Calcium-Dependent Deactivation of Focal Adhesion Kinase Targeting Colorectal Cancer Cells

Sorafenib has been recently used for the treatment of patients with advanced colorectal cancer (CRC) and is recognized for its therapeutic value. However, the continuous use of sorafenib may cause resistance in the treatment of cancer patients. In this study, we investigated whether sorafenib exerts an enhanced anticancer effect on CRC cells via the calcium-mediated deactivation of the focal adhesion kinase (FAK) signaling pathways. The appropriate dose of sorafenib and lactate calcium salt (CaLa) for a combination treatment were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Then, cell cycle analysis was performed following treatment with 2.5 μM sorafenib and/or 2.5 mM CaLa. CRC cells were found to be in the G1 phase by sorafenib treatment, and they accumulated in the sub-G1 phase with CaLa treatment. Western blots and enzyme-linked immunosorbent assays were performed to analyze the elements of the recombinant activated factor (RAF) and focal adhesion kinase (FAK) signaling cascades. Sorafenib-inhibited RAF-dependent signaling in CRC cells, however, either did not affect the expression of Akt or increased it. As the upstream signaling of FAK was suppressed by CaLa, we observed that the expression of the sub-signaling phospho (p) AKT and p-mammalian target of rapamycin was also suppressed. Treatment with a combination of sorafenib and CaLa enhanced the antitumor activity of CRC cells. The % viability of CRC cells was significantly decreased compared to the single treatment with sorafenib or CaLa, and the accumulation of Sub G1 of CRC cells was clearly confirmed. The migration ability of CRC cells was significantly reduced. The findings of this study indicate that sorafenib will show further improved antitumor efficacy against CRC due to overcoming resistance through the use of CaLa.

Combination Antitumor Effect of Sorafenib via Calcium-Dependent Deactivation of Focal Adhesion Kinase Targeting Colorectal Cancer Cells

Sorafenib has been recently used for the treatment of patients with advanced colorectal cancer (CRC) and is recognized for its therapeutic value. However, the continuous use of sorafenib may cause resistance in the treatment of cancer patients. In this study, we investigated whether sorafenib exerts an enhanced anticancer effect on CRC cells via the calcium-mediated deactivation of the focal adhesion kinase (FAK) signaling pathways. The appropriate dose of sorafenib and lactate calcium salt (CaLa) for a combination treatment were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Then, cell cycle analysis was performed following treatment with 2.5 μM sorafenib and/or 2.5 mM CaLa. CRC cells were found to be in the G1 phase by sorafenib treatment, and they accumulated in the sub-G1 phase with CaLa treatment. Western blots and enzyme-linked immunosorbent assays were performed to analyze the elements of the recombinant activated factor (RAF) and focal adhesion kinase (FAK) signaling cascades. Sorafenib-inhibited RAF-dependent signaling in CRC cells, however, either did not affect the expression of Akt or increased it. As the upstream signaling of FAK was suppressed by CaLa, we observed that the expression of the sub-signaling phospho (p) AKT and p-mammalian target of rapamycin was also suppressed. Treatment with a combination of sorafenib and CaLa enhanced the antitumor activity of CRC cells. The % viability of CRC cells was significantly decreased compared to the single treatment with sorafenib or CaLa, and the accumulation of Sub G1 of CRC cells was clearly confirmed. The migration ability of CRC cells was significantly reduced. The findings of this study indicate that sorafenib will show further improved antitumor efficacy against CRC due to overcoming resistance through the use of CaLa.

Sorafenib induces mitochondrial dysfunction and exhibits synergistic effect with cysteine depletion by promoting HCC cells ferroptosis

Hepatocellular carcinoma (HCC) is one of the most common malignant cancers worldwide. The prognosis of HCC remains poor. Currently, sorafenib is the first-line drug for advanced HCC. Although sorafenib's mechanism of action involving several established cancer-related protein kinase targets is well-characterized, the underlying molecular mechanism is still unclear. Here, we found that sorafenib inhibited viability, proliferation, and migration of HCC cells in a dose-dependent manner. Sorafenib treatment of HCC cells destroyed mitochondrial morphology, accompanied by decreased activity of oxidative phosphorylation, collapse of mitochondrial membrane potential, and reduced synthesis of ATP, with consequent cell death due to ferroptosis. Pharmacological utilization of glutathione (GSH) rescued the sorafenib-induced ferroptosis, eliminated the accumulation of cellular mitochondrial reactive oxygen species (ROS), and lipid peroxide. GSH depletion through cysteine deprivation or cysteinase inhibition exacerbated sorafenib-induced ferroptotic cell death and lipid peroxides generation, and enhanced oxidative stress and mitochondrial ROS accumulation. Collectively, these findings indicate that depletion of cysteine acts synergistically with sorafenib and renders HCC cells vulnerable to ferroptosis, presenting the potential value of new therapeutic combinations for advanced HCC.