Recent advances and novel agents for gastrointestinal stromal tumor (GIST)

M2b macrophages protect against myocardial remodeling after ischemia/reperfusion injury by regulating kinase activation of platelet-derived growth factor receptor of cardiac fibroblast

Background

Myocardial injury is a major cause of myocardial remodeling. Macrophages are important in cardiac repair as a result of their interactions with fibroblasts. As regulatory macrophages, M2b macrophages modulate inflammatory immune responses without participating in wound healing and could have enhanced protective effects on myocardial remodeling. Therefore, we tested the hypothesis that M2b macrophages could improve cardiac function and ameliorate myocardial fibrosis after the myocardial ischemia/reperfusion injury (MI/RI).

Methods

In vivo, MI/RI models were established with Sprague-Dawley (SD) rats and either M2b macrophages (MT group) or the same volume of vehicle (CK group) was injected into the ischemic zone. Two weeks after the operation, cardiac function and diameters were determined by echocardiography examination. Level of myocardial fibrosis was measured by Sirius red staining and the expression of fibrosis-related factors. In vitro, cardiac fibroblasts (CFs) were co-cultured with M2b macrophages or cultured with M2b macrophage supernatant. Expression of α-smooth muscle actin (α-SMA) and connective tissue growth factor (CCN2/CTGF) in the CFs were measured by western blotting and immunofluorescence staining. In addition, the expression of platelet-derived growth factors (PDGFs), the expression of platelet-derived growth factor receptors (PDGFRs) and the phosphorylation of PDGFRs was detected by western blotting.

Results

A significantly higher rat survival rate, improved left ventricular (LV) systolic function, decreased diameter of the LV and alleviated myocardial fibrosis were observed in the MT group than in the CK group. In vitro, the activation of CFs was significantly reduced by the M2b macrophages treatments, relative to the blank control. In addition, the kinase activation of PDGFRs was decreased by M2b macrophage treatments both in vivo and in vitro.

Conclusions

Our study demonstrated that the administration of M2b macrophages could attenuate myocardial remodeling after MI/RI. The regulation of the activation of PDGFRs in CFs is an important part of the protective mechanism.

Coincident primary breast lymphoma and gastrointestinal stromal tumor: case series and molecular mechanisms

Gastrointestinal stromal tumor (GIST) is an uncommon mesenchymal tumor, and has been shown to be associated with synchronous or metachronous second malignancies. Rare cases of coincident GIST and non-Hodgkin lymphomas (NHL) have been reported previously. Here, we report two cases of GIST and coincident primary breast lymphoma, an uncommon subtype of extranodal NHL. We propose that the exceedingly low likelihood of both these cancers occurring in these two patients by chance warrants examination for possible common oncogenic pathways in these lesions, possibly involving shared anti-apoptotic mechanisms. Further research is vital to elucidate common oncogenic pathways between such rare lesions.

Clinical development landscape in GIST: from novel agents that target accessory pathways to revisiting non-targeted therapies

INTRODUCTION

Activating mutations in the genes encoding the tyrosine receptor kinases KIT and platelet-derived growth factor receptor occur in 85%-90% of patients with gastrointestinal stromal tumors (GIST). Although imatinib and other tyrosine kinase inhibitors have revolutionized the treatment of GIST, most patients progress within a few years. Areas covered: Monoclonal antibodies and small-molecule inhibitors targeting specific signaling pathways or proteins associated with resistance to existing treatments are being explored as alternative treatment approaches for GIST. Other alternative approaches include inhibiting more general regulators of protein folding, chromatin packaging, and cell-cycle regulation; nontargeted approaches are also being evaluated in select patient populations. This review summarizes preclinical and clinical data from agents using these accessory pathways. Expert opinion: As we learn more about GIST biology, it is becoming clear that treatment strategies will become more personalized, as reflected by the fact that several trials are enrolling specific subpopulations of patients with GIST. Going forward, researchers should evaluate these new drugs alone or in combination with other types of drugs to better meet patient needs.

Integrated genomic analyses identify frequent gene fusion events and VHL inactivation in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. We sequenced nine exomes and transcriptomes, and two genomes of GISTs for integrated analyses. We detected 306 somatic variants in nine GISTs and recurrent protein-altering mutations in 29 genes. Transcriptome sequencing revealed 328 gene fusions, and the most frequently involved fusion events were associated with IGF2 fused to several partner genes including CCND1, FUS, and LASP1. We additionally identified three recurrent read-through fusion transcripts: POLA2-CDC42EP2, C8orf42-FBXO25, and STX16-NPEPL1. Notably, we found intragenic deletions in one of three exons of the VHL gene and increased mRNAs of VEGF, PDGF-β, and IGF-1/2 in 56% of GISTs, suggesting a mechanistic link between VHL inactivation and overexpression of hypoxia-inducible factor target genes in the absence of hypoxia. We also identified copy number gain and increased mRNA expression of AMACR, CRIM1, SKP2, and CACNA1E. Mapping of copy number and gene expression results to the KEGG pathways revealed activation of the JAK-STAT pathway in small intestinal GISTs and the MAPK pathway in wild-type GISTs. These observations will allow us to determine the genetic basis of GISTs and will facilitate further investigation to develop new therapeutic options.

Intratumoral Immunization by p19Arf and Interferon-β Gene Transfer in a Heterotopic Mouse Model of Lung Carcinoma

Therapeutic strategies that act by eliciting and enhancing antitumor immunity have been clinically validated as an effective treatment modality but may benefit from the induction of both cell death and immune activation as primary stimuli. Using our AdRGD-PG adenovector platform, we show here for the first time that in situ gene transfer of p19Arf and interferon-β (IFNβ) in the LLC1 mouse model of lung carcinoma acts as an immunotherapy. Although p19Arf is sufficient to induce cell death, only its pairing with IFNβ significantly induced markers of immunogenic cell death. In situ gene therapy with IFNβ, either alone or in combination with p19Arf, could retard tumor progression, but only the combined treatment was associated with a protective immune response. Specifically in the case of combined intratumoral gene transfer, we identified 167 differentially expressed genes when using microarray to evaluate tumors that were treated in vivo and confirmed the activation of CCL3, CXCL3, IL1α, IL1β, CD274, and OSM, involved in immune response and chemotaxis. Histologic evaluation revealed significant tumor infiltration by neutrophils, whereas functional depletion of granulocytes ablated the antitumor effect of our approach. The association of in situ gene therapy with cisplatin resulted in synergistic elimination of tumor progression. In all, in situ gene transfer with p19Arf and IFNβ acts as an immunotherapy involving recruitment of neutrophils, a desirable but previously untested outcome, and this approach may be allied with chemotherapy, thus providing significant antitumor activity and warranting further development for the treatment of lung carcinoma.

Platelet-derived growth factor receptor/platelet-derived growth factor (PDGFR/PDGF) system is a prognostic and treatment response biomarker with multifarious therapeutic targets in cancers

Progress in cancer biology has led to an increasing discovery of oncogenic alterations of the platelet-derived growth factor receptors (PDGFRs) in cancers. In addition, their overexpression in numerous cancers invariably makes PDGFRs and platelet-derived growth factors (PDGFs) prognostic and treatment markers in some cancers. The oncologic alterations of the PDGFR/PDGF system affect the extracellular, transmembrane and tyrosine kinase domains as well as the juxtamembrane segment of the receptor. The receptor is also involved in fusions with intracellular proteins and receptor tyrosine kinase. These discoveries undoubtedly make the system an attractive oncologic therapeutic target. This review covers elementary biology of PDGFR/PDGF system and its role as a prognostic and treatment marker in cancers. In addition, the multifarious therapeutic targets of PDGFR/PDGF system are discussed. Great potential exists in the role of PDGFR/PDGF system as a prognostic and treatment marker and for further exploration of its multifarious therapeutic targets in safe and efficacious management of cancer treatments.

Upregulation of Atoh1 correlates with favorable survival in gastrointestinal stromal tumor

Atonal homolog 1 (Atoh1) is crucial to the differentiation of many cell types and participates in tumorigenesis and progression. However, the expression of Atoh1 in gastrointestinal stromal tumors (GIST) and its relationship to clinical characteristics of this disease remain poorly understood. In this study, immunohistochemical analysis using tissue microarray (TMA) was employed to evaluate the expression of Atoh1 in GIST and the correlation between Atoh1 expression and clinicopathological features of GIST as well as patient outcome. High Atoh1 cytoplasmic expression was observed in 77.22% of patients with GIST, which was related to the mitotic index (P = 0.010) and AFIP-Miettinen risk classification (P = 0.045). High Atoh1 nuclear expression was seen in 69.49% of cases, which was associated with mitotic index (P = 0.003) and AFIP-Miettinen risk classification (P = 0.001). The Kaplan-Meier method and log-rank test indicated that high Atoh1 cytoplasmic expression, high Atoh1 nuclear expression, small tumor diameter, low mitotic index and TNM stage significantly correlated with improved survival of GIST patients. Overall, the data suggest that Atoh1 high expression correlates with a good prognosis and it may serve as a favorable prognostic factor for GIST. These results also support a role for Atoh1 as a tumor suppressor gene in GIST.

Colonic gastrointestinal stromal tumor resulting in recurrent colic and hematochezia in a warmblood gelding

A 14-year-old Trakehner gelding was evaluated for recurrent colic, with episodes occurring over 1 year. Signs were consistent with intermittent ascending colon obstruction and hematochezia. Necropsy examination revealed an ulcerated mass extending into the lumen of the right dorsal ascending colon. Gross and histologic appearance and immunoreactivity to c-kit (CD117), desmin, vimentin, and smooth muscle actin, were consistent with a diagnosis of gastrointestinal stromal tumor.

STAT inhibitors for cancer therapy

Signal Transducer and Activator of Transcription (STAT) proteins are a family of cytoplasmic transcription factors consisting of 7 members, STAT1 to STAT6, including STAT5a and STAT5b. STAT proteins are thought to be ideal targets for anti-cancer therapy since cancer cells are more dependent on the STAT activity than their normal counterparts. Inhibitors targeting STAT3 and STAT5 have been developed. These included peptidomimetics, small molecule inhibitors and oligonucleotides. This review summarized advances in preclinical and clinical development of these compounds.

Nephrotoxicity of recent anti-cancer agents

Cancer patients may develop a variety of kidney lesions that impair not only their immediate survival but also limit the adequate treatment of the underlying malignant process. This review summarizes the nephrotoxic potential of some of the most recently developed anti-cancer drugs, focusing on those interfering with the vascular endothelial growth factor and epidermal growth factor receptor pathways and mammalian target of rapamycin inhibitors. Thrombotic microangiopathy (haemolytic-uraemic syndrome), proteinuria, hypertension and magnesium depletion are the most common side effects. Also the risk for developing acute kidney injury in patients with advanced prostate cancer undergoing androgen deprivation therapy is discussed.

Selenium-binding protein 1 as a tumor suppressor and a prognostic indicator of clinical outcome

Selenium is a trace element that plays a critical role in physiological processes and cancer prevention, whose functions may be through its effects on selenium-containing proteins. Selenium-binding protein 1 (SBP1) is a member of an unusual class of selenium-containing proteins that may function as a tumor suppressor in multiple cancer types and whose levels have been shown to be lower in cancers as compared to corresponding normal tissues. This review is intended to summarize recent advances in gaining an understanding of the significance of SBP1 in carcinogenesis, and suggest that SBP1 could be developed as a potential biomarker for cancer progression and prognosis.

Phosphatidylinositol 3-kinase (PI3K) inhibitors as cancer therapeutics

Phosphatidylinositol 3-kinases (PI3Ks) are lipid kinases that regulate diverse cellular processes including proliferation, adhesion, survival, and motility. Dysregulated PI3K pathway signaling occurs in one-third of human tumors. Aberrantly activated PI3K signaling also confers sensitivity and resistance to conventional therapies. PI3K has been recognized as an attractive molecular target for novel anti-cancer molecules. In the last few years, several classes of potent and selective small molecule PI3K inhibitors have been developed, and at least fifteen compounds have progressed into clinical trials as new anticancer drugs. Among these, idelalisib has advanced to phase III trials in patients with advanced indolent non-Hodgkin's lymphoma and mantle cell lymphoma. In this review, we summarized the major molecules of PI3K signaling pathway, and discussed the preclinical models and clinical trials of potent small-molecule PI3K inhibitors.

CD133 and Ki-67 expression is associated with gastrointestinal stromal tumor prognosis

CD133⁺ tumor cells have a greater potential ability for tumorigenesis, proliferation, invasion and metastasis compared with CD133⁻ tumor cells. Ki-67 is associated with cell proliferation in various tumors and has a markedly positive correlation with the prognosis of patients. However, there are a limited number of studies that have investigated the association between the prognosis of gastrointestinal stromal tumors (GISTs) and the two markers. The present study aimed to investigate CD133 and Ki-67 expression in GISTs and to explore their clinicopathological significance in the prognosis of patients with GISTs. A total of 111 GIST patients from the Chinese People’s Liberation Army (PLA) General Hospital were retrospectively followed up and immunohistochemistry was used to detect CD133, Ki-67 and CD117 expression in the tumor samples. The survival rates of the patients were analyzed using the Kaplan-Meier method. The log-rank test, χ² test and Cox’s proportional hazards model were used to determine the association between CD133, Ki-67, CD117 expression and the prognosis of GIST. The 1-, 3- and 5-year survival rates were 93.0, 89.0 and 82.0%, respectively, in all the patients. However, in the patients with CD133⁺ or Ki-67⁺, the 1-, 3- and 5-year survival rates were 81.0, 61.5 and 50.0% and 83.0, 66.6 and 53.0%, respectively. Compared with the negative groups, the survival rates in the positive groups were statistically lower (CD133 log-rank, P=0.028; Ki-67 log-rank, P=0.002). The multivariate Cox analysis revealed that CD133 and Ki-67 expression were considerable factors in the prognosis of GIST patients (CD117, P=0.495; CD133, P=0.036; Ki-67, P=0.003). In conclusion, the positive expression of CD133 and Ki-67 was associated with a poor prognosis of GIST.

Ibrutinib and novel BTK inhibitors in clinical development

Small molecule inhibitors targeting dysregulated pathways (RAS/RAF/MEK, PI3K/AKT/mTOR, JAK/STAT) have significantly improved clinical outcomes in cancer patients. Recently Bruton's tyrosine kinase (BTK), a crucial terminal kinase enzyme in the B-cell antigen receptor (BCR) signaling pathway, has emerged as an attractive target for therapeutic intervention in human malignancies and autoimmune disorders. Ibrutinib, a novel first-in-human BTK-inhibitor, has demonstrated clinical effectiveness and tolerability in early clinical trials and has progressed into phase III trials. However, additional research is necessary to identify the optimal dosing schedule, as well as patients most likely to benefit from BTK inhibition. This review summarizes preclinical and clinical development of ibrutinib and other novel BTK inhibitors (GDC-0834, CGI-560, CGI-1746, HM-71224, CC-292, and ONO-4059, CNX-774, LFM-A13) in the treatment of B-cell malignancies and autoimmune disorders.

Gene expression network analysis of ETV1 reveals KCTD10 as a novel prognostic biomarker in gastrointestinal stromal tumor

Background

Prognostic biomarkers are required for risk stratification therapy in the patients with gastrointestinal stromal tumor (GIST). In this study, we aimed to identify prognostic biomarkers in GIST. We assessed the prognostic value of E twenty-six variant 1 (ETV1), a recently identified transcription factor unique to GIST. We also examined the clinical utility and functions of its downstream gene, potassium channel tetramerization domain containing protein 10 (KCTD10).

Methods

The levels of ETV1 and KCTD10 were evaluated immunohistochemically in 112 patients with GIST treated at two hospitals. The functional properties of KCTD10 were examined by gene silencing assay in cultured GIST cells.

Results

Immunohistochemistry revealed that ETV1 expression in GIST had no prognostic significance. In contrast, the disease-free survival rate was 88.5% in patients with KCTD10-positive tumors and 55.8% in those with KCTD10-negative tumors (p <0.0001). KCTD10 was an independent prognostic factor (p <0.05). In the low-risk classification group, KCTD10 was significantly associated with favorable prognosis (p = 0.0008). Gene silencing of KCTD10 increased cell proliferation and invasion, suggesting that KCTD10 has a tumor-suppressive function.

Conclusions

The GIST-specific transcription factor ETV1 may have no prognostic potential, whereas its downstream gene KCTD10 is associated with a favorable prognosis. Our study indicated the novel prognostic utility of KCTD10 in GIST, and suggested its tumor-suppressive effects on GIST cells. Further validation studies of KCTD10 for clinical applications, and functional verification of KCTD10 for better understanding of molecular basis of malignant phenotypes are worth challenging in GIST.

Overexpression of carbonic anhydrase II and Ki-67 proteins in prognosis of gastrointestinal stromal tumors

AIM: To investigate the expression and prognostic value of carbonic anhydrase II (CA II) and Ki-67 in gastrointestinal stromal tumors (GISTs).

METHODS: One hundred and thirteen GIST patients admitted to Chinese People’s Liberation Army General Hospital from January 2004 to December 2010 were retrospectively followed up, and immunohistochemistry was used to detect CA II, Ki-67 and CD117 expression in tumor samples. The survival rates of the patients were analyzed using the Kaplan-Meier method. Log-rank test, χ² test and Cox proportional hazards model were used to determine the relationships between CA II, Ki-67 and CD117 expression and prognostic value in GISTs.

RESULTS: The survival rates at 1, 3 and 5 years were 90.0%, 82.0% and 72.0% in all patients. However, in patients with positive CA II or Ki-67, the survival rates were 92.0%, 83.0% and 77.0% or 83.0%, 66.6% and 53.0%, respectively. Compared with the negative groups, the survival rates in the positive groups were significantly lower (CA II log-rank P = 0.000; Ki-67 log-rank P = 0.004). Multivariate Cox analysis revealed that CA II, CD117 and Ki-67 were considerable immune factors in prognosis of GIST patients (CA II P = 0.043; CD117 P = 0.042; Ki-67 P = 0.007). Besides, tumor diameter, mitotic rate, tumor site, depth of invasion, complete resection, intraoperative rupture, and adjuvant therapy were important prognosis predictive factors. Our study indicated that CA II had strong expression in GISTs and the prognosis of GISTs with high CA II expression was better than that of GISTs with low or no expression, suggesting that CA II is both a diagnostic and prognostic biomarker for GIST.

CONCLUSION: CA II and Ki-67 are significant prognostic factors for GISTs. CA II associated with neovascular endothelia could serve as a potential target for cancer therapy.

Gastrointestinal stromal tumor mesenchymal neoplasms: the offspring that choose the wrong path

Gastrointestinal stromal tumors (GISTs) are relatively rare neoplasms of the gastrointestinal tract originating from the pluripotential mesenchymal stem cells, which differentiate into interstitial Cajal cells. They are usually located in the upper gastrointestinal track. These tumors are typically defined by the expression of c-KIT (CD117) and CD34 proteins in the tumor cells. A small percentage of these tumors is negative for c-KIT. The neoplasms are positive for platelet-derived growth factor α (PDGFα) mutations. In addition to PDGFRα mutations, wild-type c-KIT mutations can also be present. The therapeutic approach to locally developed gastrointestinal stromal tumors is surgical resection, either with open or laparoscopic surgery. In case of systemic disease, molecular pharmacologic agents such as imatinib and sunitinib are used for treatment. These agents block the signaling pathways of neoplastic-cell tyrosine kinases, interfering in their proliferation and causing apoptosis.

Non-Hodgkin lymphoma and GIST: molecular pathways and clinical expressions

We report the case of a 64-year-old woman with a gastrointestinal stromal tumor and a diffuse large cell lymphoma. For this case, we conducted a literature review in an attempt to correlate these two neoplasms on a molecular basis. Diffuse large cell lymphoma is a subtype of non-Hodgkin lymphomas. The etiologic factor of these lymphomas is considered to be the mutations or allelic losses of the TP53 tumor suppressor gene and the overexpression of the bcl-2 oncogene. Gastrointestinal stromal tumors are mesenchymal tumors, which are typically defined by the expression of c-KIT (CD117) and CD34 genes in the tumor cells. Although there are references to dispersants in the literature about patients with both non-Hodgkin lymphoma and gastrointestinal stromal tumors, there is no common molecular pathway between these two diseases. In conclusion, there is no indication that these two neoplasms are relevant on a molecular basis.

Current management and prognostic features for gastrointestinal stromal tumor (GIST)

Stromal or mesenchymal neoplasms affecting the gastrointestinal (GI) tract have undergone a remarkable evolution in how they are perceived, classified, approached, diagnosed and managed over the last 30 years. Gastrointestinal stromal tumors (GIST) account for approximately 1% to 3% of all malignant GI tumors. The clinical features can vary depending on the anatomic location, size and aggressiveness of the tumor. Metastatic GIST represents a successful example of molecular targeted therapy. In this comprehensive review, we discuss the epidemiology, clinical features and diagnostic modalities for GIST. We also describe treatment options for early stage, locally advanced and metastatic GIST. Indications for neoadjuvant and adjuvant therapy along with duration of therapy are also explained. A brief discussion of latest biomarkers and updates from recent meetings is also provided.