Systemic therapy of advanced/metastatic gastrointestinal stromal tumors: an update on progress beyond imatinib, sunitinib, and regorafenib

Analysis of Potential Circular RNAs in Regulating Imatinib Resistance of Gastrointestinal Stromal Tumor

INTRODUCTION

Recent studies have found that circular RNA is an abundant RNA species that belongs to part of the competing endogenous RNA network (ceRNA), which was proven to play an important role in the development, diagnosis and progress of diseases. However, the function of circRNAs in imatinib resistance in Gastrointestinal stromal tumor (GIST) are poorly understood so for. The present study aimed to screen and predict the potential circRNAs in imatinib resistance of GIST using microarray analysis.

METHODS

We determined the expression of circular RNAs in paired normal gastric tissues (N), primary GIST (gastrointestinal stromal tumor) tissues (YC) and imatinib mesylate secondary resistance GIST tissues (C) with microarray and predicted 8677 dysregulated circular RNAs.

RESULTS

Compared with the YC group, we identified 15 circRNAs that were up-regulated and 8 circRNAs that were down-regulated in the C group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that these host linear transcripts that differentially express circular RNAs are involved in many key biological pathways, predicting the potential tumor-genesis and drug resistance mechanismrelated to HIF-1 pathway, later we draw the cirRNA-miRNA-mRNA network involved in the HIF-1 pathway and found several dysregulated circRNAs and the relationship between circRNA-miRNAs-mRNA, such as circRNA_06551, circRNA_14668, circRNA_04497, circRNA_08683, circRNA_09923(Green, down-regulation) and circRNA_23636, circRNA_15734 (Red, up-regulation).

CONCLUSION

Taken together, we identified a panel of dysregulated circRNAs that may be potential biomarkers even therapy relevant to the GIST, especially imatinib secondary resistance GIST.

Exploring the Dynamic Crosstalk between the Immune System and Genetics in Gastrointestinal Stromal Tumors

Gastrointestinal Stromal Tumors (GISTs) represent a paradigmatic model of oncogene addiction. Despite the well-known impact of the mutational status on clinical outcomes, we need to expand our knowledge to other factors that influence behavior heterogeneity in GIST patients. A growing body of studies has revealed that the tumor microenvironment (TME), mostly populated by tumor-associated macrophages (TAMs) and lymphocytes (TILs), and stromal differentiation (SD) have a significant impact on prognosis and response to treatment. Interestingly, even though the current knowledge of the role of immune response in this setting is still limited, recent pre-clinical and clinical data have highlighted the relevance of the TME in GISTs, with possible implications for clinical practice in the near future. Moreover, the expression of immune checkpoints, such as PD-L1, PD-1, and CTLA-4, and their relationship to the clinical phenotype in GIST are emerging as potential prognostic biomarkers. Looking forward, these variables related to the underlying tumoral microenvironment in GIST, though limited to still-ongoing trials, might lead to the potential use of immunotherapy, alone or in combination with targeted therapy, in advanced TKI-refractory GISTs. This review aims to deepen understanding of the potential link between mutational status and the immune microenvironment in GIST.

The role of angiogenesis in melanoma: Clinical treatments and future expectations

The incidence of melanoma has increased rapidly over the past few decades, with mortality accounting for more than 75% of all skin cancers. The high metastatic potential of Melanoma is an essential factor in its high mortality. Vascular angiogenic system has been proved to be crucial for the metastasis of melanoma. An in-depth understanding of angiogenesis will be of great benefit to melanoma treatment and may promote the development of melanoma therapies. This review summarizes the recent advances and challenges of anti-angiogenic agents, including monoclonal antibodies, tyrosine kinase inhibitors, human recombinant Endostatin, and traditional Chinese herbal medicine. We hope to provide a better understanding of the mechanisms, clinical research progress, and future research directions of melanoma.

Complete response of advanced rectal gastrointestinal stromal tumors after imatinib treatment: A case report and literature review

RATIONALE

Patients with rectal gastrointestinal stromal tumors (GISTs) who achieve a complete response (CR) with imatinib therapy have rarely been reported in the literature. Moreover, no treatment guidelines have been established for rectal GIST patients with CR after imatinib treatment, warranting further studies.

PATIENT CONCERNS

A 51-year-old man presented to our outpatient clinic in October 2013 with complaints of difficulty to defecate and a change in stool characteristics. During digital rectal examination, a mass was palpated within 5 cm from the anal verge. Contrast-enhanced computed tomography revealed a 8.1 × 7.2-cm rectal mass with significant enhancement during the arterial phase.

DIAGNOSES

A diagnosis of GIST was established after conducting needle biopsy and immunohistochemistry staining.

INTERVENTIONS

Imatinib therapy (400 mg/d, oral administration) was immediately started. When the patient achieved clinical CR (cCR), the oncologist recommended the patient to continue imatinib treatment.

OUTCOMES

At 7 months after imatinib administration, the patient achieved cCR. As suggested by the oncologist, the patient continued to receive imatinib treatment after cCR. After 13 months, the patient spontaneously stopped imatinib. Finally, tumor recurrence was observed 7 months later.

LESSONS

Surgery remains the mainstay of treatment for advanced rectal GIST patients who achieve cCR after imatinib treatment. Close follow-up and continuous imatinib treatment are indicated in patients who cannot undergo surgery.

Synthetic Approaches to the New Drugs Approved During 2020

New drugs introduced to the market are privileged structures that have affinities for biological targets implicated in human diseases and conditions. These new chemical entities (NCEs), particularly small molecules and antibody-drug conjugates (ADCs), provide insight into molecular recognition and simultaneously function as leads for the design of future medicines. This Review is part of a continuing series presenting the most likely process-scale synthetic approaches to 44 new chemical entities approved for the first time anywhere in the world during 2020.

Rapid Determination of 9 Tyrosine Kinase Inhibitors for the Treatment of Hepatocellular Carcinoma in Human Plasma by QuEChERS-UPLC-MS/MS

A reliable and rapid method employing QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) pretreatment coupled with ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was successfully developed and validated for the analysis of nine tyrosine kinase inhibitors (TKIs) in human plasma. Biological samples were extracted with acetonitrile and salted out with 350 mg of anhydrous magnesium sulfate (MgSO₄), followed by purification with 40 mg of ethyl enediamine-N-propylsilane (PSA) adsorbents. All analytes and internal standards (IS) were separated on the Hypersil GOLD VANQUISH C18 (2.1 mm × 100 mm, 1.9 μM) column using the mobile phases composed of acetonitrile (phase A) and 0.1% formic acid in water (phase B) for 8.0 min. Detection was performed by selection reaction monitoring (SRM) in the positive ion electrospray mode. Lenvatinib, sorafenib, cabozantinib, apatinib, gefitinib, regorafenib, and anlotinib rendered good linearity over the range of 0.1–10 ng/ml, and 1–100 ng/ml for tivantinib and galunisertib. All linear correlation coefficients for all standard curves were ≥ 0.9966. The limits of detection (LOD) and the limits of quantitation (LOQ) ranged from 0.003 to 0.11 ng/ml and 0.01–0.37 ng/ml, respectively. The method was deemed satisfactory with an accuracy of -7.34–6.64%, selectivity, matrix effect (ME) of 90.48–107.77%, recovery, and stability. The proposed method is simple, efficient, reliable, and applicable for the detection of TKIs in human plasma samples as well as for providing a reference for the clinical adjustment of drug administration regimen by monitoring the drug concentrations in the plasma of patients.

An Innovative Formulation Based on Nanostructured Lipid Carriers for Imatinib Delivery: Pre-Formulation, Cellular Uptake and Cytotoxicity Studies

Imatinib (IMT) is a tyrosine kinase enzyme inhibitor and extensively used for the treatment of gastrointestinal stromal tumors (GISTs). A nanostructured lipid carrier system (NLCS) containing IMT was developed by using emulsification-sonication methods. The characterization of the developed formulation was performed in terms of its particle size, polydispersity index (PDI), zeta potential, entrapment efficiency, loading capacity, sterility, syringeability, stability, in vitro release kinetics with mathematical models, cellular uptake studies with flow cytometry, fluorescence microscopy and cytotoxicity for CRL-1739 cells. The particle size, PDI, loading capacity and zeta potential of selected NLCS (F16-IMT) were found to be 96.63 ± 1.87 nm, 0.27 ± 0.15, 96.49 ± 1.46% and -32.7 ± 2.48 mV, respectively. F16-IMT was found to be stable, thermodynamic, sterile and syringeable through an 18 gauze needle. The formulation revealed a Korsmeyer-Peppas drug release model of 53% at 8 h, above 90% of cell viability, 23.61 µM of IC50 and induction of apoptosis in CRL-1739 cell lines. In the future, F16-IMT can be employed to treat GISTs. A small amount of IMT loaded into the NLCSs will be better than IMT alone for therapy for GISTs. Consequently, F16-IMT could prove to be useful for effective GIST treatment.

Neurofibromatosis in Children: Actually and Perspectives

The three types of neurofibromatosis, namely type 1, type 2, and schwannomatosis, are generally associated with various benign tumors affecting the skin and the nervous system. On rare occasions, especially in patients with neurofibromatosis type 1 (NF1), malignant neoplasms may also be present, several of them possessing a more aggressive course than in individuals without this syndrome. As such, a clear delineation between the three variants of neurofibromatosis is crucial to establish the correct diagnosis and management, as well as predict the neoplasm-related outcomes. Neurofibromin, the principal product of the NF1 gene, is a potent inhibitor of cellular proliferation, having been linked to several key signaling pathways involved in tumor growth. Therefore, it may provide a useful therapeutic target for tumor management in these patients. In this article, we want to present the association between deficiency of neurofibromin and the consequences of the lack of this protein leading to different kinds of malignant tumors. The therapy is still uncertain and most therapeutic options are in development or clinical trials.

Genotyping guided ripretinib directly after the progression of first-line imatinib therapy in advanced gastrointestinal stromal tumor: a case report

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Surgery and tyrosine kinase inhibitor (TKI) therapy are the main choices of treatment. However, the long-term use of TKIs is prone to drug resistance. Herein, we report the case of a 47-year-old female with primary gastric GIST with liver metastases since June 2015. The patient achieved disease control under imatinib therapy and underwent primary lesion resection. She took postoperative imatinib maintenance therapy, but discontinued imatinib for 10 months about 2 years after surgery. The patient suffered from disease progression in May 2019, with recurrence of liver metastases and new abdominal metastases. From then on, imatinib was resumed and partial response (PR) persisted for another 2 years. The patient subsequently experienced tumor progression due to secondary KIT exon 17 mutation confirmed by tissue biopsy and circulating tumor DNA (ctDNA) detection. After multidisciplinary team discussion, the patient received ripretinib as a second-line therapy, and ctDNA monitoring demonstrated that the KIT mutations turned negative. After disease control from ripretinib for 2+ months, she underwent cytoreductive surgery (R0/1) and received ripretinib maintenance treatment postoperatively. We believe that this case provides a reference value for individualized ripretinib precise therapy according to mutational analysis after the progression of first-line GIST treatment, and ctDNA can predict effectiveness to guide treatment.

Multiple, large intra-abdominal cystic lesions and iron deficiency anaemia as the presenting symptoms of SDHD gastrointestinal stromal tumour (GIST) in a young sub-Saharan woman

We report the case of a 27-year-old female patient from sub-Saharan Africa who presented with non-specific abdominal complaints, iron deficiency anaemia and multiple, large intra-abdominal cystic lesions on imaging. The lesions appeared to be a most unusual presentation of gastrointestinal stromal tumour (GIST). GIST is a sarcomatous tumour that comprises only 0.2% of all gastrointestinal (GI) tumours; it is the most common mesenchymal malignancy of the GI tract. Our patient had the succinate dehydrogenase-deficient (SDHD) subtype, identified in some 5%-10% of patients with GIST only, commonly found in women and younger patients. The differential diagnosis of intra-abdominal cystic lesions is briefly discussed, including the relevance of a correct pathological diagnosis. This impacts medical and surgical management decisions, including predicting response to targeted therapy. Tyrosine kinase inhibitor therapy has been a breakthrough in the treatment of GISTs, although with extensive disease, and certainly in case of the SDHD subtype, long-term outcome remains disappointing.

Genomic Characterization of Radiation-Induced Intracranial Undifferentiated Pleomorphic Sarcoma

Intracranial undifferentiated pleomorphic sarcoma remains a rare pathology within the sarcoma literature that may arise primarily or secondary after radiation therapy. Despite first-line treatment with maximal surgical resection, followed by nonstandardized adjuvant chemotherapy/radiation regimens, clinical prognosis remains exceedingly poor. Furthermore, there is a lack of genetic or molecular characterization to guide potential for targeted therapies. We present genomic analysis of a radiation-induced intracranial undifferentiated pleomorphic sarcoma in an 83-year-old woman with notable KIT and PDGFRA alterations. Further similar genomic studies of intracranial pleomorphic sarcoma are needed to develop better therapies for this rare but challenging disease entity.

Gastrointestinal Stromal Tumors (GISTs): Novel Therapeutic Strategies with Immunotherapy and Small Molecules

Gastrointestinal stromal tumors (GISTs) are the most common types of malignant mesenchymal tumors in the gastrointestinal tract, with an estimated incidence of 1.5/100.000 per year and 1–2% of gastrointestinal neoplasms. About 75–80% of patients have mutations in the KIT gene in exons 9, 11, 13, 14, 17, and 5–10% of patients have mutations in the platelet-derived growth factor receptor a (PDGFRA) gene in exons 12, 14, 18. Moreover, 10–15% of patients have no mutations and are classified as wild type GIST. The treatment for metastatic or unresectable GISTs includes imatinib, sunitinib, and regorafenib. So far, GIST therapies have raised great expectations and offered patients a better quality of life, but increased pharmacological resistance to tyrosine kinase inhibitors is often observed. New treatment options have emerged, with ripretinib, avapritinib, and cabozantinib getting approvals for these tumors. Nowadays, immune checkpoint inhibitors form a new landscape in cancer therapeutics and have already shown remarkable responses in various tumors. Studies in melanoma, non-small-cell lung cancer, and renal cell carcinoma are very encouraging as these inhibitors have increased survival rates. The purpose of this review is to present alternative approaches for the treatment of the GIST patients, such as combinations of immunotherapy and novel inhibitors with traditional therapies (tyrosine kinase inhibitors).