Role of c-Met in cancer: emphasis on lung cancer

Unravelling the role of tumor microenvironment responsive nanobiomaterials in spatiotemporal controlled drug delivery for lung cancer therapy

Design and development of efficient drug delivery technologies that impart site-specificity is the need of the hour for the effective treatment of lung cancer. The emergence of materials science and nanotechnology partially helped drug delivery scientists to achieve this objective. Various stimuli-responsive materials that undergo degradation at the pathological tumor microenvironment (TME) have been developed and explored for drug delivery applications using nanotechnological approaches. Nanoparticles (NPs), owing to their small size and high surface area to volume ratio, demonstrated enhanced cellular internalization, permeation, and retention at the tumor site. Such passive accumulation of stimuli-responsive materials helped to achieve spatiotemporally controlled and targeted drug delivery within the tumors. In this review, we discussed various stimuli-physical (interstitial pressure, temperature, and stiffness), chemical (pH, hypoxia, oxidative stress, and redox state), and biological (receptor expression, efflux transporters, immune cells, and their receptors or ligands)-that are characteristic to the TME. We mentioned an array of biomaterials-based nanoparticulate delivery systems that respond to these stimuli and control drug release at the TME. Further, we discussed nanoparticle-based combinatorial drug delivery strategies. Finally, we presented our perspectives on challenges related to scale-up, clinical translation, and regulatory approvals.

Altered expression of cytokines, chemokines, growth factors, and soluble receptors in patients with colorectal cancer, and correlation with treatment outcome

Insofar as they play an important role in the pathogenesis of colorectal cancer (CRC), this study analyzes the serum profile of cytokines, chemokines, growth factors, and soluble receptors in patients with CRC and cancer-free controls as possible CRC signatures. Serum levels of 65 analytes were measured in patients with CRC and age- and sex-matched cancer-free controls using the ProcartaPlex Human Immune Monitoring 65-Plex Panel. Of the 65 tested analytes, 8 cytokines (CSF-3, IFN-γ, IL-12p70, IL-18, IL-20, MIF, TNF-α and TSLP), 8 chemokines (fractalkine, MIP-1β, BLC, Eotaxin-1, Eotaxin-2, IP-10, MIP-1a, MIP-3a), 2 growth factors (FGF-2, MMP-1), and 4 soluble receptors (APRIL, CD30, TNFRII, and TWEAK), were differentially expressed in CRC. ROC analysis confirmed the high association of TNF-α, BLC, Eotaxin-1, APRIL, and Tweak with AUC > 0.70, suggesting theranostic application. The expression of IFN-γ, IL-18, MIF, BLC, Eotaxin-1, Eotaxin-2, IP-10, and MMP1 was lower in metastatic compared to non-metastatic CRC; only AUC of MIF and MIP-1β were > 0.7. Moreover, MDC, IL-7, MIF, IL-21, and TNF-α are positively associated with tolerance to CRC chemotherapy (CT) (AUC > 0.7), whereas IL-31, Fractalkine, Eotaxin-1, and Eotaxin-2 were positively associated with resistance to CT. TNF-α, BLC, Eotaxin-1, APRIL, and Tweak may be used as first-line early detection of CRC. The variable levels of MIF and MIP-1β between metastatic and non-metastatic cases assign prognostic nature to these factors in CRC progression. Regarding tolerance to CT, MDC, IL-7, MIF, IL-21, and TNF-α are key when down-regulated or resistant to treatment is observed.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

MiRNA-related metastasis in oral cancer: moving and shaking

Across the world, oral cancer is a prevalent tumor. Over the years, both its mortality and incidence have grown. Oral cancer metastasis is a complex process involving cell invasion, migration, proliferation, and egress from cancer tissue either by lymphatic vessels or blood vessels. MicroRNAs (miRNAs) are essential short non-coding RNAs, which can act either as tumor suppressors or as oncogenes to control cancer development. Cancer metastasis is a multi-step process, in which miRNAs can inhibit or stimulate metastasis at all stages, including epithelial-mesenchymal transition, migration, invasion, and colonization, by targeting critical genes in these pathways. On the other hand, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two different types of non-coding RNAs, can regulate cancer metastasis by affecting gene expression through cross-talk with miRNAs. We reviewed the scientific literature (Google Scholar, Scopus, and PubMed) for the period 2000-2023 to find reports concerning miRNAs and lncRNA/circRNA-miRNA-mRNA networks, which control the spread of oral cancer cells by affecting invasion, migration, and metastasis. According to these reports, miRNAs are involved in the regulation of metastasis pathways either by directly or indirectly targeting genes associated with metastasis. Moreover, circRNAs and lncRNAs can induce or suppress oral cancer metastasis by acting as competing endogenous RNAs to inhibit the effect of miRNA suppression on specific mRNAs. Overall, non-coding RNAs (especially miRNAs) could help to create innovative therapeutic methods for the control of oral cancer metastases.

Ran GTPase and Its Importance in Cellular Signaling and Malignant Phenotype

Ran is a member of the Ras superfamily of proteins, which primarily regulates nucleocytoplasmic trafficking and mediates mitosis by regulating spindle formation and nuclear envelope (NE) reassembly. Therefore, Ran is an integral cell fate determinant. It has been demonstrated that aberrant Ran expression in cancer is a result of upstream dysregulation of the expression of various factors, such as osteopontin (OPN), and aberrant activation of various signaling pathways, including the extracellular-regulated kinase/mitogen-activated protein kinase (ERK/MEK) and phosphatidylinositol 3-kinase/Protein kinase B (PI3K/Akt) pathways. In vitro, Ran overexpression has severe effects on the cell phenotype, altering proliferation, adhesion, colony density, and invasion. Therefore, Ran overexpression has been identified in numerous types of cancer and has been shown to correlate with tumor grade and the degree of metastasis present in various cancers. The increased malignancy and invasiveness have been attributed to multiple mechanisms. Increased dependence on Ran for spindle formation and mitosis is a consequence of the upregulation of these pathways and the ensuing overexpression of Ran, which increases cellular dependence on Ran for survival. This increases the sensitivity of cells to changes in Ran concentration, with ablation being associated with aneuploidy, cell cycle arrest, and ultimately, cell death. It has also been demonstrated that Ran dysregulation influences nucleocytoplasmic transport, leading to transcription factor misallocation. Consequently, patients with tumors that overexpress Ran have been shown to have a higher malignancy rate and a shorter survival time compared to their counterparts.

Artonin F Induces the Ubiquitin-Proteasomal Degradation of c-Met and Decreases Akt-mTOR Signaling

Targeted therapies that selectively inhibit certain molecules in cancer cells have been considered promising for cancer treatment. In lung cancer, evidence has suggested that mesenchymal-epithelial transition factor (c-Met) oncoprotein drives cancer progression through its signaling transduction pathway. In this paper, we report the downregulation of c-Met by artonin F, a flavonoid isolated from Artocarpus gomezianus. Artonin F was found to be dominantly toxic to lung cancer cells by mediating apoptosis. With regard to its mechanism of action, artonin F downregulated c-Met expression, consequently suppressed the phosphatidylinositol-3 kinase/Akt/mammalian target of rapamycin signaling, increased Bax expression, decreased Bcl-2 expression, and activated caspase-3. The depletion of c-Met was mediated by ubiquitin-proteasomal degradation following co-treatment with artonin F, with the proteasome inhibitor MG132 reversing its c-Met-targeting effect. The immunoprecipitation analysis revealed that artonin F significantly promoted the formation of the c-Met–ubiquitin complex. Given that ubiquitin-specific protease 8 (USP8) prevents c-Met degradation by deubiquitination, we performed a preliminary in silico molecular docking and observed that artonin F blocked the catalytic site of USP8. In addition, artonin F interacted with the catalytic residues of palmitoylating enzymes. By acting as a competitive inhibitor, artonin F could reduce the degree of palmitoylation of c-Met, which affected its stability and activity. In conclusion, c-Met is critical for cancer cell survival and the failure of chemotherapeutic regimens. This novel information on the c-Met downregulating effect of artonin F will be beneficial for the development of efficient anticancer strategies or targeted therapies.

Protein Phosphatase 2A as a Therapeutic Target in Small Cell Lung Cancer

Protein phosphatase 2A (PP2A), a serine/threonine phosphatase involved in the regulation of apoptosis, proliferation, and DNA-damage response, is overexpressed in many cancers, including small cell lung cancer (SCLC). Here we report that LB100, a small molecule inhibitor of PP2A, when combined with platinum-based chemotherapy, synergistically elicited an antitumor response both in vitro and in vivo with no apparent toxicity. Using inductively coupled plasma mass spectrometry, we determined quantitatively that sensitization via LB100 was mediated by increased uptake of carboplatin in SCLC cells. Treatment with LB100 alone or in combination resulted in inhibition of cell viability in two-dimensional culture and three-dimensional spheroid models of SCLC, reduced glucose uptake, and attenuated mitochondrial and glycolytic ATP production. Combining LB100 with atezolizumab increased the capacity of T cells to infiltrate and kill tumor spheroids, and combining LB100 with carboplatin caused hyperphosphorylation of the DNA repair marker γH2AX and enhanced apoptosis while attenuating MET signaling and invasion through an endothelial cell monolayer. Taken together, these data highlight the translational potential of inhibiting PP2A with LB100 in combination with platinum-based chemotherapy and immunotherapy in SCLC.

New Preclinical Development of a c-Met Inhibitor and Its Combined Anti-Tumor Effect in c-Met-Amplified NSCLC

c-Met is a receptor tyrosine kinase with no commercially available product despite being a pivotal target in cancer progression. Unlike other c-Met inhibitors that fail clinically, ABN401 is a newly synthesized c-Met inhibitor that is not potentially degraded by aldehyde oxidase (AO) in human liver cytosol. This study aimed to determine the physicochemical stability, pharmacokinetics in beagle dogs, and therapeutic effect of ABN401 in a c-Met-amplified non-small-cell lung cancer (NSCLC) patient-derived xenograft (PDX) model. ABN401 was found to be a weak basic compound, with pKa and log P values of 7.49 and 2.46, respectively. It is poorly water-soluble but soluble at acidic pH. The accelerated storage stability is dependent on temperature, but the purity remains at over 97% after 6 months. The bioavailability is approximately 30% in dogs and it is highly efficient in the PDX model, achieving around 90% tumor growth inhibition in combination with erlotinib. These observations indicate that the compound is acceptable for the next phase of trials.

Dose-escalation trial of the ALK, MET & ROS1 inhibitor, crizotinib, in patients with advanced cancer

Aim: This first-in-human, dose-finding study evaluated safety, pharmacokinetics and pharmacodynamics of crizotinib and established a recommended Phase II dose (RP2D) among patients with advanced solid malignancies. Patients & methods: Patients received oral crizotinib in a 3 + 3 dose escalation design. Results: Thirty-six patients received crizotinib (50 mg once daily-300 mg twice daily); maximum tolerated dose (and RP2D) was 250 mg twice daily. Most patients (89%) experienced ≥1 treatment-related adverse event. Three patients had grade 3 dose-limiting toxicities: alanine aminotransferase increased (n = 1) and fatigue (n = 2). Generally, an increase in soluble MET was found with increasing crizotinib concentrations. Conclusion: Crizotinib demonstrated a favorable safety profile. The observed pharmacodynamic effect on soluble MET provide evidence for targeted MET inhibition by crizotinib. Clinicaltrials. gov identifier: NCT00585195.

Selenium nanoparticles induce autophagy mediated cell death in human keratinocytes

Aim: Selenium nanoparticles (SeNPs) may have a potential role in treating dermal disorders due to its wide therapeutic properties, but there is a need to evaluate its toxicity in keratinocytes. The present study evaluated the molecular mechanism and mode of cell death induced by SeNPs on dermal keratinocytes. Materials & methods: SeNPs were synthesized, characterized and studied in human keratinocytes cells. Oxidative stress and mitochondrial membrane depolarization were evaluated by various techniques. Additionally, autophagy mediated apoptotic cell death was evaluated. Results: SeNPs induced oxidative stress and apoptotic cell death in keratinocytes by increasing autophagy through the formation of acidic lysosomes and autophagosomes. Conclusion: Overall, SeNPs induce the oxidative stress and autophagy mediated apoptotic cell death in human keratinocytes cells.

Kinase impact assessment in the landscape of fusion genes that retain kinase domains: a pan-cancer study

Assessing the impact of kinase in gene fusion is essential for both identifying driver fusion genes (FGs) and developing molecular targeted therapies. Kinase domain retention is a crucial factor in kinase fusion genes (KFGs), but such a systematic investigation has not been done yet. To this end, we analyzed kinase domain retention (KDR) status in chimeric protein sequences of 914 KFGs covering 312 kinases across 13 major cancer types. Based on 171 kinase domain-retained KFGs including 101 kinases, we studied their recurrence, kinase groups, fusion partners, exon-based expression depth, short DNA motifs around the break points and networks. Our results, such as more KDR than 5'-kinase fusion genes, combinatorial effects between 3'-KDR kinases and their 5'-partners and a signal transduction-specific DNA sequence motif in the break point intronic sequences, supported positive selection on 3'-kinase fusion genes in cancer. We introduced a degree-of-frequency (DoF) score to measure the possible number of KFGs of a kinase. Interestingly, kinases with high DoF scores tended to undergo strong gene expression alteration at the break points. Furthermore, our KDR gene fusion network analysis revealed six of the seven kinases with the highest DoF scores (ALK, BRAF, MET, NTRK1, NTRK3 and RET) were all observed in thyroid carcinoma. Finally, we summarized common features of 'effective' (highly recurrent) kinases in gene fusions such as expression alteration at break point, redundant usage in multiple cancer types and 3'-location tendency. Collectively, our findings are useful for prioritizing driver kinases and FGs and provided insights into KFGs' clinical implications.

Overexpression of GRB2 Enhances Epithelial to Mesenchymal Transition of A549 Cells by Upregulating SNAIL Expression

GRB2 is an adaptor protein which interacts with phosphorylated TGF-β receptor and is critical for mammary tumour growth. We found that TGF-β1-induced EMT increased GRB2 expression in A549 cells (non-small cell lung cancer). Overexpression of GRB2 (A549^GRB2) enhanced cell invasion while knocking down GRB2 (A549^GRB2KD) reduced cell migration and invasion, probably due to increased vinculin and reduced Paxillin patches in A549^GRB2KD cell. TGF-β1-induced EMT was more pronounced in A549^GRB2 cells and attenuated in A549^GRB2KD cells. This could be due to the reduced expression of E-cadherin in A549^GRB2 and increased expression of E-cadherin in A549^GRB2KD cells, even before TGF-β1 stimulation. Expression of SNAIL was elevated in A549^GRB2 cells and was further enhanced by TGF-β1 stimulation, suggesting that GRB2 down-regulates E-cadherin by enhancing the expression of SNAIL. The N-SH3 domain of GRB2 was critical for suppressing E-cadherin expression, while the C-SH3 domain of GRB2 mediating interaction with proteins such as N-WASP was critical for promoting invasion, and the SH2 domain was critical for suppressing E-cadherin expression and invasion. Thus, our data suggests that GRB2 enhances EMT by suppressing E-cadherin expression and promoting invasion probably through N-WASP to promote metastasis.

Hepatocyte growth factor is a prognostic marker in patients with colorectal cancer: a meta-analysis

Hepatocyte growth factor (HGF) is a crucial factor associated with development, progression and metastasis of colorectal cancer (CRC). However, its prognostic value remains unclear. Thus studies referring to the correlation between HGF and CRC patients’ prognosis were included to explore the role of HGF in CRC. At last nine articles were included. The results showed that the over-expression of HGF was associated with a poor prognosis, presented through overall survival (OS, Hazard ratio (HR) = 2.50, 95% confidence interval (CI): 2.12–2.96) and disease-free survival (DFS, HR = 1.99, 95% CI: 1.59–2.50). Subgroup analysis indicated that no significant difference was found between the Asian countries (OS: HR = 2.37; DFS: HR = 2.02) and the non-Asian countries (OS: HR = 3.15; DFS: HR = 1.87), between the studies that used univariate analyses (OS: HR = 2.51; DFS: HR = 2.07) and those that used multivariate analyses (OS: HR = 2.65; DFS: HR = 1.78), and between metastatic CRC (OS: HR = 2.26; DFS: HR = 2.06) and stage I-IV CRC (OS: HR = 3.08; DFS: HR = 0.70). Our meta-analysis has shown that the over-expression of HGF is valuable in CRC prognosis evaluation. This conclusion should be further confirmed by large-sample cohort studies.

Gene expression profiles and signaling mechanisms in α2B-adrenoceptor-evoked proliferation of vascular smooth muscle cells

BACKGROUND

α2-adrenoceptors are important regulators of vascular tone and blood pressure. Regulation of cell proliferation is a less well investigated consequence of α2-adrenoceptor activation. We have previously shown that α2B-adrenoceptor activation stimulates proliferation of vascular smooth muscle cells (VSMCs). This may be important for blood vessel development and plasticity and for the pathology and therapeutics of cardiovascular disorders. The underlying cellular mechanisms have remained mostly unknown. This study explored pathways of regulation of gene expression and intracellular signaling related to α2B-adrenoceptor-evoked VSMC proliferation.

RESULTS

The cellular mechanisms and signaling pathways of α2B-adrenoceptor-evoked proliferation of VSMCs are complex and include redundancy. Functional enrichment analysis and pathway analysis identified differentially expressed genes associated with α2B-adrenoceptor-regulated VSMC proliferation. They included the upregulated genes Egr1, F3, Ptgs2 and Serpine1 and the downregulated genes Cx3cl1, Cav1, Rhoa, Nppb and Prrx1. The most highly upregulated gene, Lypd8, represents a novel finding in the VSMC context. Inhibitor library screening and kinase activity profiling were applied to identify kinases in the involved signaling pathways. Putative upstream kinases identified by two different screens included PKC, Raf-1, Src, the MAP kinases p38 and JNK and the receptor tyrosine kinases EGFR and HGF/HGFR. As a novel finding, the Src family kinase Lyn was also identified as a putative upstream kinase.

CONCLUSIONS

α2B-adrenoceptors may mediate their pro-proliferative effects in VSMCs by promoting the activity of bFGF and PDGF and the growth factor receptors EGFR, HGFR and VEGFR-1/2. The Src family kinase Lyn was also identified as a putative upstream kinase. Lyn is known to be expressed in VSMCs and has been identified as an important regulator of GPCR trafficking and GPCR effects on cell proliferation. Identified Ser/Thr kinases included several PKC isoforms and the β-adrenoceptor kinases 1 and 2. Cross-talk between the signaling mechanisms involved in α2B-adrenoceptor-evoked VSMC proliferation thus appears to involve PKC activation, subsequent changes in gene expression, transactivation of EGFR, and modulation of kinase activities and growth factor-mediated signaling. While many of the identified individual signals were relatively small in terms of effect size, many of them were validated by combining pathway analysis and our integrated screening approach.

The latest therapeutic strategies after resistance to first generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) in patients with non-small cell lung cancer (NSCLC)

First-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), gefitinib and erlotinib, produce reliable responses and survival benefits in selected patients with advanced non-small cell lung cancer (NSCLC). Unfortunately, most patients who initially respond to first-line therapy with EGFR TKIs will experience disease progression in 1-2 years. To overcome the resistance of EGFR TKIs, the potent resistance mechanisms and novel therapeutic strategies have been developed. T790M mutation and activation of bypass signaling pathway are identified the predominant mechanisms of acquired resistance to TKIs. Several approaches have shown promise, such as next-generation EGFR TKIs, immunotherapy, and combinational therapies. And the limited clinical data suggest that all drugs are acceptable safe. Additionally, this review will also focus on the increasingly importance of re-biopsy at the time of disease progression, and the matching effective therapies is related to the identification of specific molecular types of tumors.

In-depth proteomic analysis of six types of exudative pleural effusions for nonsmall cell lung cancer biomarker discovery

Pleural effusion (PE), a tumor-proximal body fluid, may be a promising source for biomarker discovery in human cancers. Because a variety of pathological conditions can lead to PE, characterization of the relative PE proteomic profiles from different types of PEs would accelerate discovery of potential PE biomarkers specifically used to diagnose pulmonary disorders. Using quantitative proteomic approaches, we identified 772 nonredundant proteins from six types of exudative PEs, including three malignant PEs (MPE, from lung, breast, and gastric cancers), one lung cancer paramalignant PE, and two benign diseases (tuberculosis and pneumonia). Spectral counting was utilized to semiquantify PE protein levels. Principal component analysis, hierarchical clustering, and Gene Ontology of cellular process analyses revealed differential levels and functional profiling of proteins in each type of PE. We identified 30 candidate proteins with twofold higher levels (q<0.05) in lung cancer MPEs than in the two benign PEs. Three potential markers, MET, DPP4, and PTPRF, were further verified by ELISA using 345 PE samples. The protein levels of these potential biomarkers were significantly higher in lung cancer MPE than in benign diseases or lung cancer paramalignant PE. The area under the receiver-operator characteristic curve for three combined biomarkers in discriminating lung cancer MPE from benign diseases was 0.903. We also observed that the PE protein levels were more clearly discriminated in effusions in which the cytological examination was positive and that they would be useful in rescuing the false negative of cytological examination in diagnosis of nonsmall cell lung cancer-MPE. Western blotting analysis further demonstrated that MET overexpression in lung cancer cells would contribute to the elevation of soluble MET in MPE. Our results collectively demonstrate the utility of label-free quantitative proteomic approaches in establishing differential PE proteomes and provide a new database of proteins that can be used to facilitate identification of pulmonary disorder-related biomarkers.

Ceritinib

Objective: To review ceritinib for the treatment of anaplastic lymphoma kinase (ALK)-positive metastatic non–small-cell lung cancer (NSCLC). Data Sources: Literature searches were conducted in PubMed, EMBASE (1974 to July week 5, 2014), and Google Scholar using the terms ceritinib, LDK378, and non–small-cell lung cancer. Study Selection and Data Extraction: One phase 1 trial and 2 abstracts were identified. Data Synthesis: Ceritinib is approved for the treatment of ALK-positive metastatic NSCLC in patients who are intolerant to or have progressed despite therapy with crizotinib. In the phase 1 clinical trial, the maximum tolerated dose was determined to be 750 mg once daily. The overall response rate (ORR) was 58% (95% CI = 48-67) in patients who received ≥400 mg daily (n = 114). In this group, the ORR was 56% (95% CI = 41-67) and 62% (95% CI = 44-78) among crizotinib-exposed and -naïve patients, respectively. The ORR was 59% (95% CI = 47-70) in patients who received 750 mg daily (n = 78). The ORR was 56% (95% CI = 41-70) in crizotinib-treated patients and 64% (95% CI = 44-81) in crizotinib-naïve patients, respectively, in this subset. The median duration of response was 8.2 months. Median progression-free survival was 7.0 months. The most common adverse reactions included diarrhea, nausea, vomiting, abdominal pain, anorexia, constipation, fatigue, and elevated transaminases. Conclusions: Ceritinib has activity in crizotinib-resistant and crizotinib-naïve patients and appears to be a viable alternative for ALK-positive NSCLC. Long-term data are needed to further define the role of ceritinib in the treatment of NSCLC.

Activation of c-Met and upregulation of CD44 expression are associated with the metastatic phenotype in the colorectal cancer liver metastasis model

BACKGROUND

Liver metastasis is the most common cause of death in patients with colorectal cancer. Despite extensive research into the biology of cancer progression, the molecular mechanisms that drive colorectal cancer metastasis are not well characterized.

METHODS

HT29 LM1, HT29 LM2, HT29 LM3 cell lines were derived from the human colorectal cancer cell line HT29 following multiple rounds of in vivo selection in immunodeficient mice.

RESULTS

CD44 expression, a transmembrane glycoprotein involved in cell-cell and cell-matrix adhesions, and cancer cells adhesion to endothelial cells was increased in all in vivo selected cell lines, with maximum CD44 expression and cancer cells adhesion to endothelial cells in the highly metastatic HT29 LM3 cell line. Activation of c-Met upon hepatocyte growth factor (HGF) stimulation in the in vivo selected cell lines is CD44 independent. In vitro separation of CD44 high and low expression cells from HT29 LM3 cell line with FACS sorting confirmed that c-Met activation is CD44 independent upon hepatocyte growth factor stimulation. Furthermore, in vivo evaluation of CD44 low and high expressing HT29 LM3 cells demonstrated no difference in liver metastasis penetrance.

CONCLUSIONS

Taken together, our findings indicate that the aggressive metastatic phenotype of in vivo selected cell lines is associated with overexpression of CD44 and activation of c-MET. We demonstrate that c-Met activation is CD44 independent upon hepatocyte growth factor stimulation and confirm that CD44 expression in HT29 LM3 cell line is not responsible for the increase in metastatic penetrance in HT29 LM3 cell line.

Unmet needs and challenges in gastric cancer: the way forward

Although the incidence of gastric cancer has fallen steadily in developed countries over the past 50 years, outcomes in Western countries remain poor, primarily due to the advanced stage of the disease at presentation. While earlier diagnosis would help to improve outcomes for patients with gastric cancer, better understanding of the biology of the disease is also needed, along with advances in therapy. Indeed, progress in the treatment of gastric cancer has been limited, mainly because of its genetic complexity and heterogeneity. As a result, there is an urgent need to apply precision medicine to the management of the disease in order to ensure that individuals receive the most appropriate treatment. This article suggests a number of strategies that may help to accelerate progress in treating patients with gastric cancer. Incorporation of some of these approaches could help to improve the quality of life and survival for patients diagnosed with the disease. Standardisation of care across Europe through expansion of the European Registration of Cancer Care (EURECCA) registry - a European cancer audit that aims to improve quality and decrease variation in care across the region - may also be expected to lead to improved outcomes for those suffering from this common malignancy.

Forthcoming prognostic markers for esophageal cancer: a systematic review and meta-analysis

BACKGROUND

The incidence of esophageal cancer is rising, and survival rates remain poor. This meta-analysis summarizes five molecular mechanisms of disease progression, which are related to prognosis.

PATIENTS AND METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google Scholar, Science Direct, and Web of Science. Original data was abstracted from each study and used to calculate a pooled event rate and 95% confidence interval (95% CI).

RESULTS

Our analysis included five octamer-binding transcription factor 4 (OCT4) studies (564 patients), six sex determining region Y-box 2 (SOX2) studies (336 patients), five oestrogen receptor (ER) studies (367 patients), seven MET or MNNG HOS Transforming gene (c-Met) studies (1,015 patients) and six insulin like growth factor receptor studies (764 patients). Incidence of OCT4 in SCC was 53.60% (95% CI: 0.182-0.857) and the overall hazard ratio for poor clinic outcome was 2.9 (95% CI: 1.843-4.565). The incidence of SOX2 in SCC was 69.2% (95% CI: 0.361-0.899) however, was associated with significant heterogeneity of 90.94%. The prevalence of Oestrogen receptor α and β in SCC were 37.90% (95% CI: 0.317-0.444) and 67.20% (95% CI: 0.314-0.901) respectively. The prevalence of MET in EAC was 33.20% (95% CI: 0.031-0.884) and the incidence of insulin-like growth factor-1 receptor (IGF-1R) in EAC was 67.70% (95% CI: 0.333-0.898).

CONCLUSIONS

Our results show that the status of ER, OCT4 and SOX2 expression correlates with the unfavourable prognosis in patients with esophageal squamous cell carcinoma (ESCC). This study also highlights the potential impact of the IGF-1R on the biology of EAC and the expression of Met was recognised as a significant prognostic factor. Our data supports the concept of IGF axis, ER, Met, OCT4 and SOX2 inhibition as (neo-) adjuvant treatment.

Synergistic inhibition of cell migration by tetraspanin CD82 and gangliosides occurs via the EGFR or cMet-activated Pl3K/Akt signalling pathway

The metastasis suppressor CD82/KAI-1, which is a member of the tetraspanin superfamily, has been proposed to exert its activity together with glycosphingolipids. However, the mechanism of CD82 inhibition has not been fully elucidated. The present study aimed to investigate the synergistic inhibition of cell migration by the tetraspanin CD82 and gangliosides and to correlate this inhibition with activation of epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (HGFR/cMet) in Hepa1-6 cell lines, whose motility and migration is stimulated by epidermal growth factor (EGF) and hepatocyte growth factor (HGF) in vitro. We found that Hepa1-6 cells transfected with the CD82 gene exhibited decreased migration in response to EGF and HGF. EGF-stimulated phosphorylation of EGFR at Tyr1173 was inhibited in these cells, which contributed to the attenuation of EGFR. Ectopic expression of CD82 in Hepa1-6 cells inhibited HGF-stimulated tyrosine phosphorylation of cMet at Tyr1313 and Tyr1365 without affecting the expression of cMet. These inhibitory effects were enhanced when CD82 was introduced with Ganglioside GM3 alone or GM2/GM3. Reduction of CD82 expression by RNA interference together with depletion of glycosphingolipids with P4 significantly enhanced cell motility and increased the expression of EGFR and its phosphorylation at Tyr1173 in response to EGF. Increased cell motility and HGF-dependent activation of cMet at Tyr1313 and Tyr1365 resulted from decreased CD82 levels and increased GM3. Furthermore, CD82 expression selectively attenuated EGFR and cMet signalling via phosphatidylinositol 3-kinase/Akt but had no affect on the activity of the MAPK signalling pathway. These results suggest that the synergistic effects of CD82 and GM3 or GM2/GM3 on EGFR expression and phosphorylation and cMet activation are responsible for CD82 inhibition of EGF- and HGF-dependent cell motility and migration of Hepa1-6 cells.

Podoplanin-positive cancer-associated fibroblasts could have prognostic value independent of cancer cell phenotype in stage I lung squamous cell carcinoma: usefulness of combining analysis of both cancer cell phenotype and cancer-associated fibroblast phenotype

BACKGROUND

The prognostic significance of the tumor microenvironment, which is created by both cancer cells and cancer-associated fibroblasts (CAFs), has been increasingly recognized. The purpose of this study was to analyze the prognostic markers of stage I squamous cell carcinoma (SqCC), with special reference to the immunophenotypes of both cancer cells and CAFs.

METHODS

A total of 142 patients with stage I SqCC were included in this study. We examined the expressions of E-cadherin, laminin-5, podoplanin, c-MET, carbonic anhydrase IX (CA-IX), CD10, and CD44 in the cancer cells and those of podoplanin, CA-IX, CD10, and CD44 in the CAFs to evaluate their prognostic value.

RESULTS

Patients with low E-cadherin expression in the cancer cells showed a significantly poorer prognosis than those with high E-cadherin expression in the cancer cells ( P , .001). On the other hand, high podoplanin expression in the CAFs was also associated with a significantly poorer prognosis ( P , .001). A multivariate analysis identified low E-cadherin expression in the cancer cells and high podoplanin expression in the CAFs as significantly independent prognostic factors for overall survival ( P 5 .013 and P 5 .0011, respectively). According to subgroup analyses combining E-cadherin expression in cancer cells and podoplanin expression in CAFs, 5-year overall survival of patients with low E-cadherin expression in the cancer cells and high podoplanin expression in the CAFs was 7.0% and showed a significantly poorer prognosis as compared with other groups ( P , .001).

CONCLUSIONS

The current study indicates that immunophenotypes of CAFs could have a prognostic value independent of those of the cancer cells in SqCC.

Phosphorylation of cMet tyrosine residues in murine ascitic hepatic cancer cell lines with different lymph node metastatic potentials

The aim of the present study was to determine the molecular mechanism by which the hepatocyte growth factor (HGF) receptor (cMet) regulates lymphatic metastasis in hepatocellular carcinoma. Mouse hepatoma ascites cell lines with different lymph node metastatic potentials, Hca‑F (high metastatic potential) and Hca‑P (low metastatic potential), were cultured in vitro. Cells were treated with HGF, fibronectin (FN) and laminin (LN), and the phosphorylated tyrosine residues of cMet and the activities of intracellular phospholipase Cγ/diacylglycerol/protein kinase C (PLCγ/DAG/PKC) and phosphoinositol‑3‑kinase/protein kinase B (PI3K/AKT) signaling pathways were analyzed comparatively in the two cell lines using western blot analysis and migration assays. Following HGF treatment, the phosphorylation of cMet at Tyr 1313 and 1365 in Hca‑F cells was higher, while the phosphorylation of cMet at Tyr 1349 was lower than that in Hca‑P. The activity of PLCγ/DAG/PKC was increased in Hca‑F cells compared with Hca‑P cells, whereas the activity of PI3K/AKT was reduced. After FN treatment, the phosphorylation of cMet at Tyr 1313 and the activity of the PLCγ/DAG/PKC signaling pathway was increased in Hca‑F cells compared with Hca‑P cells. Following LN treatment, the phosphorylation of cMet at Tyr 1365 and the activity of PLCγ/DAG/PKC was higher in Hca‑F cells than in Hca‑P cells. Results of the current study indicate that a number of ligands stimulate the phosphorylation of cMet at various tyrosine residues, activating different signaling transduction pathways. In addition, the same ligand was observed to phosphorylate different tyrosine residues on cMet in the two cell lines, as well as activate different intracellular signaling transduction pathways. After cMet is activated, various tyrosine residues are phosphorylated, leading to the activation of the PI3K/AKT and PLCγ/DAG/PKC signaling pathways to different extents in the two cells lines. These results may be important in determining the lymph node metastatic potentials of the two cell lines.

Strengthening context-dependent anticancer effects on non-small cell lung carcinoma by inhibition of both MET and EGFR

The MET and EGFR receptor tyrosine kinases (RTK) are often coexpressed and may cross-talk in driving the development and progression of non-small cell lung carcinoma (NSCLC). In addition, MET amplification is an alternative resistance mechanism for escaping EGFR-targeted therapy. To assess the benefits of combined targeting of MET and EGFR for treating NSCLCs, we investigated the activities of these two RTK pathways in NSCLC cell lines and evaluated their responses to SGX523 and erlotinib, the small-molecule kinase inhibitors of MET and EGFR, respectively. We showed that MET interacts with and cross-activates EGFR in MET-amplified or -overexpressed cells. The inhibition of both MET and EGFR results in maximal suppression of downstream signaling and of cell proliferation when their ligands are present. Furthermore, we showed that SGX523 plus erlotinib strengthens anticancer activity in vivo in a cellular context-dependent manner. The combination led to the regression of H1993 tumors by enhancing the suppression of proliferation and inducing apoptosis, whereas H1373 tumor growth was significantly reduced by the combination via suppression of proliferation without inducing apoptosis. SGX523 alone was sufficient to achieve near-complete regression of EBC-1 tumors; its combination with erlotinib strongly inhibited the viability of a population of insensitive cells emerging from an SGX523-treated EBC-1 tumor recurrence. Our data suggest that inhibition of both MET and EGFR can enhance anticancer effects against NSCLCs in a context-dependent manner and thus provide a strong rationale for combining MET and EGFR inhibitors in treating NSCLCs.

Cancer-linked targets modulated by curcumin

In spite of major advances in oncology, the World Health Organization predicts that cancer incidence will double within the next two decades. Although it is well understood that cancer is a hyperproliferative disorder mediated through dysregulation of multiple cell signaling pathways, most cancer drug development remains focused on modulation of specific targets, mostly one at a time, with agents referred to as "targeted therapies," "smart drugs," or "magic bullets." How many cancer targets there are is not known, and how many targets must be attacked to control cancer growth is not well understood. Although more than 90% of cancer-linked deaths are due to metastasis of the tumor to vital organs, most drug targeting is focused on killing the primary tumor. Besides lacking specificity, the targeted drugs induce toxicity and side effects that sometimes are greater problems than the disease itself. Furthermore, the cost of some of these drugs is so high that most people cannot afford them. The present report describes the potential anticancer properties of curcumin, a component of the Indian spice turmeric (Curcuma longa), known for its safety and low cost. Curcumin can selectively modulate multiple cell signaling pathways linked to inflammation and to survival, growth, invasion, angiogenesis, and metastasis of cancer cells. More clinical trials of curcumin are needed to prove its usefulness in the cancer setting.

Met kinetic signature derived from the response to HGF/SF in a cellular model predicts breast cancer patient survival

To determine the signaling pathways leading from Met activation to metastasis and poor prognosis, we measured the kinetic gene alterations in breast cancer cell lines in response to HGF/SF. Using a network inference tool we analyzed the putative protein-protein interaction pathways leading from Met to these genes and studied their specificity to Met and prognostic potential. We identified a Met kinetic signature consisting of 131 genes. The signature correlates with Met activation and with response to anti-Met therapy (p<0.005) in in-vitro models. It also identifies breast cancer patients who are at high risk to develop an aggressive disease in six large published breast cancer patient cohorts (p<0.01, N>1000). Moreover, we have identified novel putative Met pathways, which correlate with Met activity and patient prognosis. This signature may facilitate personalized therapy by identifying patients who will respond to anti-Met therapy. Moreover, this novel approach may be applied for other tyrosine kinases and other malignancies.

MET amplification identifies a small and aggressive subgroup of esophagogastric adenocarcinoma with evidence of responsiveness to crizotinib

PURPOSE

Amplification of the MET proto-oncogene in gastroesophageal cancer (GEC) may constitute a molecular marker for targeted therapy. We examined a GEC cohort with follow-up and reported the clinical response of four additional patients with MET-amplified tumors to the small molecule inhibitor crizotinib as part of an expanded phase I cohort study.

PATIENTS AND METHODS

From 2007 to 2009, patients with GEC were genetically screened as a consecutive series of 489 tumors (stages 0, I, and II, 39%; III, 25%; IV, 36%; n = 222 esophageal, including n = 21 squamous carcinomas). MET, EGFR, and HER2 amplification status was assessed by using fluorescence in situ hybridization.

RESULTS

Ten (2%) of 489 patients screened harbored MET amplification; 23 (4.7%) harbored EGFR amplification; 45 (8.9%) harbored HER2 amplification; and 411 (84%) were wild type for all three genes (ie, negative). MET-amplified tumors were typically high-grade adenocarcinomas that presented at advanced stages (5%; n = 4 of 80). EGFR-amplified tumors showed the highest fraction of squamous cell carcinoma (17%; n = 4 of 23). HER2, MET, and EGFR amplification were, with one exception (MET and EGFR positive), mutually exclusive events. Survival analysis in patients with stages III and IV disease showed substantially shorter median survival in MET/EGFR-amplified groups, with a rank order for all groups by median survival (from most to least aggressive): MET (7.1 months; P < .001) less than EGFR (11.2 months; P = .16) less than HER2 (16.9 months; P = .89) when compared with the negative group (16.2 months). Two of four patients with MET-amplified tumors treated with crizotinib experienced tumor shrinkage (-30% and -16%) and experienced progression after 3.7 and 3.5 months.

CONCLUSION

MET amplification defines a small and aggressive subset of GEC with indications of transient sensitivity to the targeted MET inhibitor crizotinib (PF-02341066).

Molecular profiles of EGFR, K-ras, c-met, and FGFR in pulmonary pleomorphic carcinoma, a rare lung malignancy

BACKGROUND

Pulmonary pleomorphic carcinoma (PPC) is a rare type of lung cancer characterized by the poor response to conventional chemotherapy and subsequent disappointing outcomes. Therefore, it is paramount to delineate the molecular characteristics of this disease entity.

METHODS

In this study, we retrospectively examined the surgical specimens of 61 patients who underwent lung surgery. Mutational or gene amplification statuses of epidermal growth factor receptor (EGFR), k-ras, c-kit, c-met, and fibroblast growth factor receptor (FGFR) were examined using genomic DNA sequencing, real-time PCR and/or fluorescence in situ hybridization (FISH).

RESULTS

The median age was 61 years, and 50 patients were men and 11 were women. In the histologic review of epithelial component, adenocarcinoma were in 44 cases (72%), squamous cell carcinoma in 15 (25%) and large cell carcinoma in 2 patients (3%). Overall, 30 cases (49%) had any molecular alterations. Nine patients (15%) possessed EGFR deletion in exon 19 (n = 8) or L858R mutations in exon 21 (n = 1), while 3 other cases having atypical EGFR mutations. Six patients (9.8%) had k-ras mutations in exon 12, and 3 had c-kit mutations. High gene copy number of c-met was found in 11 patients (18.0%) and that of FGFR was in 6 patients (9.8%). No significant relationships were identified among the occurrence and type of mutations and patient survival or any other clinicopathological variables.

CONCLUSIONS

Given the diverse repertoire of mutational profiles observed in PPC samples, clinical trials based on accurate cancer-genotyping should be considered as a legitimate treatment scheme for this rare disease entity in the future.

Role of protein kinase C β and vascular endothelial growth factor receptor in malignant pleural mesothelioma: Therapeutic implications and the usefulness of Caenorhabditis elegans model organism

PURPOSE

To examine the role of both protein kinase C (PKC)-β and vascular endothelial growth factor receptor (VEGFR)-2 in malignant pleural mesothelioma (MPM) using respective inhibitors, enzastaurin and KRN633.

MATERIALS AND METHODS

MPM cell lines, control cells, and a variety of archived MPM tumor samples were used to determine the protein expression levels of PKC-β, VEGFR-2, VEGF, and p-AKT. Effects of enzastaurin and KRN633 on phosphorylation status of key signaling molecules and viability of the mesothelioma cells were determined. The common soil nematode, Caenorhabditis elegans, was treated with enzastaurin to determine its suitability to screen for highly potent kinase inhibitors.

RESULTS

PKC-β1, PKC-β2 and VEGFR-2/KDR were overexpressed in MPM cell lines and MPM tumor tissues. Enzastaurin treatment resulted in significant loss in viability of VEGF induced cell proliferation; however, the effect of KRN633 was much less. Enzastaurin also dramatically decreased the phosphorylation of PKC-β, its downstream target p-AKT, and surprisingly, the upstream VEGFR-2. The combination of the two drugs at best was additive and similar results were obtained with respect to cell viability. Treatment of C. elegans with enzastaurin resulted in clear phenotypic changes and the worms were hypermotile with abnormal pattern and shape of eggs, suggesting altered fecundity.

CONCLUSIONS

PKC-β1 and VEGFR-2 are both excellent therapeutic targets in MPM. Enzastaurin was better at killing MPM cells than KRN633 and the combination lacked synergy. In addition, we show here that C. elegans can be used to screen for the next generation inhibitors as treatment with enzastaurin resulted in clear phenotypic changes that could be assayed.

Hepatic growth factor (HGF) inhibits cigarette smoke extract induced apoptosis in human bronchial epithelial cells

Low concentrations of cigarette smoke induced DNA damage and repair without leading to apoptosis in human bronchial epithelial cells. Higher concentrations of cigarette smoke, however, could induce either apoptosis or necrosis. The current study demonstrated that 15% cigarette smoke extract (CSE) induced apoptosis as evidenced by DNA content profiling (17.8±2.1% vs 10.2±1.6% of control, p<0.05), LIVE/DEAD staining (60.2±2.1% viable cells in CSE-treated vs 86.5±2.3% in control cells, p<0.05), and COMET assay (24.3±0.6% of Apoptotic Index in the cells treated with CSE vs 4.7±0.6% of control, P<0.05). Hepatocyte growth factor (HGF) significantly blocked the cigarette smoke-induced apoptosis as shown by DNA profiling (10.8±1.5% of CSE+HGF, p<0.05), LIVE/DEAD staining (78.5±1.2% in CSE+HGF treated cells, p<0.05), and COMET assay (Apoptotic Index: 10.0±0.8% in CSE+HGF treated cells, P<0.05). This protective effect of HGF on CSE-induced apoptosis was abolished by PI3K inhibitors, wortmannin and LY294002, and by introduction of the dominant negative AKT into the cells. Furthermore, CSE plus HGF could induce phosphorylation of AKT Thr 308 and the pro-apoptotic protein, BAD. These results suggest that HGF modulates cell survival in response to cigarette smoke exposure through the PI3K/AKT signaling pathway.

Molecular networks in respiratory epithelium carcinomas

Current anti-cancer research is focused on cell surface receptors targeting, mainly epidermal growth factor receptor and vascular endothelial growth factor receptor, against which a few targeted agents are now available in clinical practice. Recent improvements of our understanding on the intracellular networks that participate in respiratory epithelium carcinogenesis have further elucidated the role of a variety of molecules that represent attractive targets for novel therapeutic strategies. The aim of this review is to explore the potential therapeutic opportunities of the manipulation of these pathways.

Plexin B1 suppresses c-Met in melanoma: a role for plexin B1 as a tumor-suppressor protein through regulation of c-Met

Melanoma arises through complex genetic and epigenetic changes, resulting in uncontrolled proliferation, invasion, and metastatic disease. Semaphorins regulate axon guidance through interaction with their receptors, plexins and neuropilins. Plexin B1, the semaphorin 4D receptor, activates oncogenic receptors c-Met and ErbB-2 in several cell types, suggesting it promotes tumor growth through stimulation of these receptors. A study by Argast et al. has shown that plexin B1 is a tumor-suppressor protein for melanoma metastasis in a mouse model. In this report, we show that plexin B1 is lost in metastatic and deeply invasive melanoma in patient samples in vivo. Unexpectedly, introduction of plexin B1 into human melanoma cell lines suppressed, rather than activated, the oncogenic receptor, c-Met, by its ligand hepatocyte growth factor (HGF). Plexin B1 also activated Akt in melanoma. Plexin B1 significantly abrogated cell migration in response to HGF but rendered cells resistant to apoptosis by cisplatin. Plexin B1 is predicted to function as a classic tumor-suppressor protein in melanoma, in part through suppression of c-Met signaling and c-Met-dependent migration. However, because plexin B1 activates Akt, a multifunctional protein involved in tumor progression in several cancers, plexin B1 may function as a tumor promoter in melanomas not driven by c-Met activation.

Does hepatocyte growth factor/c-Met signal play synergetic role in lung cancer?

There is growing evidence that the signal pathway between hepatocyte growth factor (HGF) and its receptor c-Met plays an important role in the development of lung cancer, although the specificity of such role is to be clarified. It seems clear that the HGF/c-Met signal contributes to the metastasis of cancer cells to the lung by stimulating the hyperproduction and overactivation of cytokines and enzymes, e.g. HGF, vascular endothelial growth factor and matrix metalloproteases. The HGF/c-Met signal may act as the candidate responsible for the development of epidermal growth factor receptor (EGFR) kinase inhibitor resistance. Experimental evidence showed that the combination of both EGFR and c-Met inhibitors had synergetic or additive therapeutic effects on lung cancer. Although the mechanism of interaction between HGF/c-Met and transforming growth factor-a/EGFR remains unclear, the cross-talk and balance between those two signal pathways are critical and necessary in the development of new therapies for lung cancer.