Ramucirumab, another anti-angiogenic agent for metastatic colorectal cancer in second-line setting--its impact on clinical practice

Targeting Cancer Stem Cells as the Key Driver of Carcinogenesis and Therapeutic Resistance

The emerging concept of cancer stem cells (CSCs) as the key driver behind carcinogenesis, progression, and diversity has displaced the prior model of a tumor composed of cells with similar subsequently acquired mutations and an equivalent capacity for renewal, invasion, and metastasis. This significant change has shifted the research focus toward targeting CSCs to eradicate cancer. CSCs may be characterized using cell surface markers. They are defined by their capacity to self-renew and differentiate, resist conventional therapies, and generate new tumors following repeated transplantation in xenografted mice. CSCs' functional capabilities are governed by various intracellular and extracellular variables such as pluripotency-related transcription factors, internal signaling pathways, and external stimuli. Numerous natural compounds and synthetic chemicals have been investigated for their ability to disrupt these regulatory components and inhibit stemness and terminal differentiation in CSCs, hence achieving clinical implications. However, no cancer treatment focuses on the biological consequences of these drugs on CSCs, and their functions have been established. This article provides a biomedical discussion of cancer at the time along with an overview of CSCs and their origin, features, characterization, isolation techniques, signaling pathways, and novel targeted therapeutic approaches. Additionally, we highlighted the factors endorsed as controlling or helping to promote stemness in CSCs. Our objective was to encourage future studies on these prospective treatments to develop a framework for their application as single or combined therapeutics to eradicate various forms of cancer.

Molecular docking and molecular dynamic studies: screening of phytochemicals against EGFR, HER2, estrogen and NF-KB receptors for their potential use in breast cancer

Breast cancer (BC) is a second common malignancy in female globally. Hence, identification of novel therapeutic agents is extremely important. Molecular docking and MD simulation are the important tools in the process of drug discovery for searching the potential hits. The structure-based drug designing technique also reveals the information about ligands behavior in computational environment. Docking tools help in visualization and analysis of protein-ligand complex at atomic level. Molecular dynamics shows the stability of the molecules in the receptor cavity in the simulated environment. In this research work, we have screened potent phytochemicals against the BC. We docked the phytochemicals and examined the binding affinities of ligands towards the EGFR, HER2, estrogen and NF-κB receptors. Pristimerin, ixocarpalactone A, viscosalactone B and zhankuic acid A have shown higher binding affinities and energies towards targeted receptors among the screened phytochemicals. MD simulation study shows stability of docked complex for pristimerin and HER2 receptor. These phytochemicals can be repurposed for their anticancer activity. This in-silico work provides a strong ground for further investigation of their anticancer activity.

Safety Profile and Adverse Events of Special Interest for Fruquintinib in Chinese Patients with Previously Treated Metastatic Colorectal Cancer: Analysis of the Phase 3 FRESCO Trial

INTRODUCTION

In FRESCO (Fruquintinib Efficacy and Safety in 3+ Line Colorectal Cancer Patients) trial, fruquintinib demonstrated a statistically significant and clinically meaningful overall survival benefit in Chinese patients with metastatic colorectal cancer (mCRC). However, its safety profile, including adverse events of special interest (AESIs) and treatment-emergent adverse events (TEAEs) by age, sex, and body mass index (BMI), is not well known. The present analysis evaluated the safety profile and AESIs for fruquintinib in the FRESCO trial.

METHODS

In FRESCO, eligible Chinese patients were randomized (2:1) to receive fruquintinib (5 mg once daily for 3 weeks, followed by 1 week off in 28-day cycles) or placebo plus best supportive care. Treatment-related AESIs and time to first occurrence of AESIs were summarized. Treatment-related TEAEs by age, sex, and BMI were also summarized.

RESULTS

A total of 266 patients (95.7%) in the fruquintinib group and 97 (70.8%) in the placebo group had at least one treatment-related TEAE; the mean relative dose intensity was 92% and 98%, respectively. In the fruquintinib group, the most common (in > 40% of patients) treatment-related AESIs were hypertension (55.4%), palmar-plantar erythrodysesthesia syndrome [known as hand-foot skin reaction (HFSR)] (49.3%), and proteinuria (42.1%). The most common treatment-related grade ≥ 3 AESIs (≥ 3% of patients) were hypertension (21.2%), HFSR (10.8%), and proteinuria (3.2%); the median time to onset of these events was 10, 21, and 20 days, respectively. Subgroup analysis by age, sex, and BMI revealed that the frequencies of treatment-related TEAEs were similar across all subgroups, and were consistent with the overall safety profile of fruquintinib.

CONCLUSIONS

The most common treatment-related grade ≥ 3 AEs were hypertension, HFSR, and proteinuria. The treatment-related TEAE profile of fruquintinib in Chinese patents with mCRC was comparable among different subgroups and consistent with that reported in the overall population.

TRIAL REGISTRATION

Clinical Trials identifier NCT02314819.

Selective Vascular Endothelial Growth Factor Receptor Inhibitors Provide Limited Benefits for Metastatic Colorectal Cancer: A Meta-Analysis

BACKGROUND

Metastatic colorectal cancer (mCRC) is one of the most common and deadly cancers worldwide. For most patients diagnosed with mCRC and managed with 5-fluorouracil (5-FU)/leucovorin plus oxaliplatin (FOLFOX), the median survival time is still less than 2 years. Small molecule selective vascular endothelial growth factor receptor (VEGFR) inhibitors have been demonstrated to have strong anti-tumour activity in various cancer models.

OBJECTIVE

To demonstrate the efficacy and safety of selective VEGFR inhibitors in the management of mCRC.

METHODS

A comprehensive search in PubMed, EMBASE, Web of Science, Ovid MEDLINE, Google Scholar, Springer and Cochrane Central databases was performed for randomized controlled trials (RCTs) focusing on the effect of selective VEGFR inhibitors on mCRC. The primary outcome measures were progression-free survival (PFS) rates, overall survival (OS) rates, complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), objective response rates (ORRs), disease control rates (DCRs) and adverse effect (AE) rates. The dates of the included studies ranged from the inception of the database to January 15, 2020.

RESULTS

Twenty-two RCTs were included. A total of 9362 patients met the inclusion criteria. Compared with placebo, selective VEGFR inhibitors significantly increased the PFS rate, SD, PR and DCR, reduced PD, caused more treatment-emergent adverse events (TEAEs), hypertension, hand-foot skin reaction, diarrhoea, fatigue, and thrombocytopaenia and increased aspartate aminotransferase(AST) concentration. There was no significant difference between selective VEGFR inhibitors and placebo regarding OS rate, CR, ORR, proteinuria, hyperbilirubinaemia or alkaline phosphatase(ALP) concentration. Additionally, compared with FOLFOX4+placebo, FOLFOX4+ selective VEGFR inhibitors, clearly reduced PD, and caused more 3-4 AEs, serious AEs, hypertension, hand-foot syndrome, diarrhoea, nausea, vomiting, decreased appetite, dehydration, fatigue, dizziness, neutropaenia and thrombocytopaenia. For PFS rate, OS rate, CR, PR, SD, ORR, abdominal pain, peripheral sensory neuropathy, asthaenia, anaemia and hypokalaemia rates, there was no significant difference between FOLFOX4+ selective VEGFR inhibitors and FOLFOX4+placebo. However, compared with FOLFOX4+bevacizumab, FOLFOX4+selective VEGFR inhibitors, led to increased hypertension, neutropaenia, fatigue, thrombocytopaenia and asthaenia. There is no clear difference between FOLFOX4+selective VEGFR inhibitors and FOLFOX4+ bevacizumab with regard to PFS rate, OS rate, CR, PR, SD, PD, ORR, diarrhoea, nausea, vomiting, peripheral neuropathy and abdominal pain rates. Selective VEGFR inhibitors+cetuximab increased PFS and PR and reduced PD compared to cetuximab, but there was no statistical difference between the two groups for OS and SD.

CONCLUSION

Compared with placebo or cetuximab, selective VEGFR inhibitors alone or combined with cetuximab seemed to be more efficacious for mCRC respectively; however, the effects were not better than FOLFOX4 alone or when combined with bevacizumab for mCRC. Additionally, selective VEGFR inhibitors were not as safe as placebo or FOLFOX4 alone or in combination with bevacizumab in mCRC.

Identification of potential anticancer phytochemicals against colorectal cancer by structure-based docking studies

Colorectal cancer (CRC) is the third most common malignancy among both the genders globally. Therefore, searching of new therapeutic options is utmost priority. Molecular docking is a widely used tool in drug discovery to identify potential new therapeutic targets. Molecular docking plays a vital role in the visualization of ligand-protein interaction at an atomic level and enhancing our understanding of the ligand behavior thus aiding in the structure-based drug designing. Selected phytochemicals with potential anticancer activities were examined for their binding affinities to the selected VEGFR and EGFR receptors. The receptor protein 3D structures were obtained from Protein Data Bank, and the molecular docking was performed using UCSF Chimera software with its AutoDock Vina tool. Out of 18 compounds screened, Yuanhuanin, Theaflavin, and Genistein have shown highest binding energies. Findings of this study should be further evaluated for their potential use in CRC treatment, management, and prevention.

Targeting Receptor Kinases in Colorectal Cancer

Colorectal cancer is the third most common malignancy in men and the second most common cancer in women. Despite the success of screening programs and the development of adjuvant therapies, the global burden of colorectal cancer is expected to increase by 60% to more than 2.2 million new cases and 1.1 million deaths by 2030. In recent years, a great effort has been made to demonstrate the utility of protein kinase inhibitors for cancer treatment. Considering this heterogeneous disease is defined by mutations that activate different Receptor Tyrosine Kinases (RTKs) and affect downstream components of RTK-activated transduction pathways, in this review we analyze the potential utility of different kinase inhibitors for colorectal cancer treatment.

Precision treatment in colorectal cancer: Now and the future

Until recently, a one‐drug‐fits‐all model was applied to every patient diagnosed with the same condition. But not every condition is the same, and this has led to many cases of ineffective treatment. Pharmacogenetics is increasingly used to stratify patients for precision medicine treatments, for instance, the UGT1A1*28 polymorphism as a dosage indicator for the use of irinotecan as well as epidermal growth factor receptor (EGFR) immunohistochemistry and KRAS Proto‐Oncogene (KRAS) exon 2 mutation tests for determining the likelihood of treatment response to cetuximab or panitumumab treatment in metastatic colorectal cancer (CRC). The other molecular subtypes, such as KRAS exon 3/4, B‐Raf Proto‐Oncogene, NRAF, PIK3CA, and PETN, were also reported as potential new pharmacogenetic targets for the current and the newly discovered anticancer drugs. In addition to next‐generation sequencing (NGS), primary tumor cells for in vivo and in vitro drug screening, imaging biomarker 3′‐Deoxy‐3′‐18F‐fluorothymidine positron emission tomography, and circulating tumor DNA (ctDNA) detection methods are being developed and may represent the future direction of precision medicine. This review will discuss the current environment of precision medicine, including clinically approved targeted therapies, the latest potential therapeutic agents, and the ongoing pharmacogenetic trials for CRC patients.

Impaired tumor growth and angiogenesis in mice heterozygous for Vegfr2 (Flk1)

VEGF signaling through its tyrosine kinase receptor, VEGFR2 (FLK1), is critical for tumor angiogenesis. Previous studies have identified a critical gene dosage effect of VegfA in embryonic development and vessel homeostasis, neovascularization, and tumor growth, and potent inhibitors of VEGFR2 have been used to treat a variety of cancers. Inhibition of FGFR signaling has also been considered as an antiangiogenic approach to treat a variety of cancers. Inhibition of VEGFR2 with neutralizing antibodies or with pharmacological inhibitors of the VEGFR tyrosine kinase domain has at least short-term efficacy with some cancers; however, also affects vessel homeostasis, leading to adverse complications. We investigate gene dosage effects of Vegfr2, Fgfr1, and Fgfr2 in three independent mouse models of tumorigenesis: two-stage skin chemical carcinogenesis, and sub-cutaneous transplantation of B16F0 melanoma and Lewis Lung Carcinoma (LLC). Mice heterozygous for Vegfr2 display profound defects in supporting tumor growth and angiogenesis. Unexpectedly, additional deletion of endothelial Fgfr1 and Fgfr2 in Vegfr2 heterozygous mice shows similar tumor growth and angiogenesis as the Vegfr2 heterozygous mice. Notably, hematopoietic deletion of two alleles of Vegfr2 had minimal impact on tumor growth, with little effect on angiogenesis, reinforcing the importance of endothelial Vegfr2 heterozygosity. These studies reveal previously unrecognized Vegfr2 gene dosage effects in tumor angiogenesis and a lack of synergy between VEGFR2 and endothelial FGFR1/2 signaling during tumor growth.

Efficacy and safety of targeting VEGFR drugs in treatment for advanced or metastatic gastric cancer: a systemic review and meta-analysis

The value of targeting VEGFR (vascular endothelial growth factor receptor) drugs has demonstrated encouraging anti-cancer activity in advanced solid tumors within current clinical trials. This study aimed to serve as the first systemic review to assess their safety and efficacy according to biochemical characteristics of targeting VEGFR drugs in gastric cancer. We analyzed eight clinical trials on targeting VEGFR drugs in gastric cancer. Results showed that targeting VEGFR drugs significantly improved overall survival (OS) [Hazard Ratio (HR) 0.69, 95% confidence interval (CI) (0.55, 0.83), P < 0.001], progression free survival (PFS) [HR 0.50, 95% CI (0.34, 0.66), P < 0.001], disease control rate (DCR) [Odds Ratio (OR) 3.83, 95% CI (2.39, 6.15), P < 0.001] and significantly decreased the progressive disease rate(PDR)[OR 0.45, 95% CI (0.34, 0.59), P < 0.001], but not objective response rate (ORR) [OR 1.46, 95% CI (0.93, 2.29), P = 0.098]. Further subgroup revealed that VEGFR antibody (VEGFR-Ab) drugs were superior to VEGFR tyrosine kinase inhibitor (VEGFR-TKI) drugs in terms of the OS, PFS and PDR. To determine the toxic effect of targeting VEGFR drugs, the relative risk of adverse events (grade ≥ 3) of special interest(AESIs) were estimated. Most of these were predictable and manageable. Furthermore, less AESIs were observed in the VEGFR-Ab than the VEGFR-TKI drugs. In conclusion, VEGFR drugs were effective targeted therapy in advanced or metastatic gastric cancer, and its toxicity is within a controllable range. VEGFR-Ab drugs were more effective than VEGFR-TKI drugs in terms of the OS, PFS and PDR of gastric cancer patients with little toxicity.

Involvement of breast cancer stem cells in tumor angiogenesis

The aim of the present study was to investigate the role of breast cancer stem cells (BCSCs) in the angiogenesis of breast cancer tumors. The expression levels of mutant p53, cluster of differentiation (CD)31, vascular endothelial factor (VEGF), in addition to human epidermal growth factor (HER)2, were detected in the blood vessels of human breast cancer (BC) tissue samples. CD44⁺/CD24^-/low cells were selected from single-cell suspensions of BC tissues to assess the expression of CD31 and CD105, in addition to the ability of these cells to metabolize acetylated low-density lipoprotein (Ac-LDL). Furthermore, vascular-like structures were observed histologically. Mutant p53, CD31 and VEGF were all expressed in these tissues. CD44⁺ cells comprised 7.5±2.6 and 94.3±4.7% of the cell population prior to and following sorting, respectively. CD24⁺ cells comprised 48.2±9.4 and 4.3±4% of the cell population prior to and following sorting, respectively. A low proportion of CD24⁺ cells corresponded to a high proportion of CD24^-/low cells. The percentages of CD105⁺ and CD31⁺ glomus cells in the mammary gland were 4.5±0.9 and 6.2±1.3%, respectively, and following passaging for three generations, these increased to 79.6±9.3 and 84.1±10.7%, respectively (P<0.05). Cells were cultured using an endothelial cell culture system, and they internalized DiL-Ac-LDL. Here, vascular endothelial cells formed vascular-like structures, whereas the control group demonstrated no such structures. Overall, the results suggest that BCSCs-derived endothelial cells may contribute to tumor angiogenesis.

Role of modern immunotherapy in gastrointestinal malignancies: a review of current clinical progress

Gastrointestinal (GI) cancers are a group of highly aggressive malignancies with a huge disease burden worldwide. There is clearly a significant unmet need for new drugs and therapies to further improve the treatment outcomes of GI malignancies. Immunotherapy is a novel treatment strategy that is emerging as an effective and promising treatment option against several types of cancers. CTLA-4 and PD-1 are critical immune checkpoint molecules that negatively regulate T cell activation via distinct mechanisms. Immune checkpoint blockade with antibodies directed against these pathways has already shown clinical efficacy that has led to their FDA approval in the treatment of several solid tumors including melanoma, non-small cell lung cancer, renal cell carcinoma, urothelial carcinoma, and head and neck cancer. This review will summarize the current clinical progress of modern immunotherapy in the field of GI tumors, with a special focus on immune checkpoint blockade.

Safety and efficacy of fruquintinib in patients with previously treated metastatic colorectal cancer: a phase Ib study and a randomized double-blind phase II study

BACKGROUND

To assess the efficacy and safety of fruquintinib, a vascular endothelial growth factor receptor (VEGFR) inhibitor, in metastatic colorectal cancer (mCRC) patients.

METHODS

A phase Ib open-label study and phase II randomized, placebo-controlled trial compared the efficacy of fruquintinib plus best supportive care (BSC) with placebo plus BSC in mCRC patients with ≥2 lines of prior therapies. The primary endpoint was progression-free survival (PFS).

RESULTS

In the phase Ib study, 42 patients took fruquintinib 5 mg for 3 weeks on/1 week off. The median PFS was 5.80 months, and the median overall survival (OS) was 8.88 months. In the phase II study, 71 patients were randomized (47 to fruquintinib, 24 to placebo). PFS was significantly improved with fruquintinib plus BSC (4.73 months; 95% confidence interval [CI] 2.86-5.59) versus placebo plus BSC (0.99 months; 95% CI 0.95-1.58); (hazard ratio [HR] 0.30; 95% CI 0.15-0.59; P < 0.001). The median OS was 7.72 versus 5.52 months (HR 0.71; 95% CI 0.38-1.34). The most common grade 3-4 adverse events were hypertension and hand-foot skin reaction.

CONCLUSIONS

Fruquintinib showed a significant PFS benefit of 3.7 months in patients with treatment-refractory mCRC. The safety profile was consistent with that of VEGFR tyrosine kinase inhibitors. A randomized phase III confirmatory study in mCRC is underway.

TRIAL REGISTRATION

NCT01975077 and NCT02196688.

Efficacy and safety of angiogenesis inhibitors in advanced gastric cancer: a systematic review and meta-analysis

Monoclonal antibodies and small molecule tyrosine kinase inhibitors (TKIs) directed against the vascular endothelial growth factor (VEGF) or its receptors have been investigated in several studies for the treatment of advanced gastric cancer (GC). In the present study, we aimed to evaluate the efficacy and safety of angiogenesis inhibitors in advanced GC. We searched published randomized controlled trials (RCTs) comparing angiogenesis inhibitors with non-angiogenesis inhibitors for the treatment of GC. MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched. The extracted data on progression-free survival (PFS) and overall survival (OS) were measured in terms of hazard ratios (HR) and corresponding 95 % confidence intervals (CIs). In addition, risk ratios (RR) and corresponding 95 % CIs were pooled for objective response rate (ORR), disease control rate (DCR), and risk of adverse events (AEs). Ten RCTs involving 2786 patients were included. Compared with non-angiogenesis inhibitor-containing regimens, angiogenesis inhibitor-containing regimens resulted in a significant improvement in OS (HR 0.80, 95 % CI 0.69-0.93, P = 0.004), prolonged PFS (HR 0.66, 95 % CI 0.51-0.86, P = 0.002), and superior ORR (RR 1.34, 95 % CI 1.09-1.65, P = 0.005) and DCR (RR 1.37, 95 % CI 1.17-1.61, P = 0.0001). Angiogenesis inhibitors were associated with a greater number of AEs, but most of these were predictable and manageable. However, hand-foot syndrome, diarrhea, and gastrointestinal (GI) perforation were significantly increased in patients treated with angiogenesis inhibitors. In summary, angiogenesis inhibitor-containing regimens were superior to non-angiogenesis inhibitor-containing regimens in terms of OS, PFS, RR, and DCR in patients with advanced GC.

Current targeted therapies in the treatment of advanced colorectal cancer: a review

Treatment strategies for metastatic colorectal cancer (mCRC) patients have undergone dramatic changes in the past decade and despite improved patient outcomes, there still exist areas for continued development. The introduction of targeted agents has provided clinicians with additional treatment options in mCRC, however, results have been mixed at best. These novel therapies were designed to interfere with specific molecules involved in the cellular carcinogenesis pathway and ultimately deliver a more focused treatment. Currently, their use in mCRC has been limited primarily as an adjunct to conventional chemotherapy regimens. This review explores the relevant cell-signaling networks in colorectal cancer, provides focus on the current targeted agent armamentarium approved for use in mCRC and explores the usefulness of predictive mCRC biomarkers.