Distinct genetic aberrations in oesophageal adeno and squamous carcinoma

Novel oncogenic transcriptional targets of mutant p53 in esophageal squamous cell carcinoma

Missense mutations in the DNA binding domain of p53 are observed frequently in esophageal squamous cell carcinoma (ESCC). Recent studies have revealed the potentially oncogenic transcriptional networks regulated by mutant p53 proteins. However, majority of these studies have focused on common "hotspot" p53 mutations while rarer mutations are poorly characterized. In this study, we report the characterization of rare, "non-hotspot" p53 mutations from ESCC. In vitro tumorigenic assays performed following ectopic-expression of certain "non-hotspot" mutant p53 proteins caused enhancement of oncogenic properties in squamous carcinoma cell lines. Genome-wide transcript profiling of ESCC tumor samples stratified for p53 status, revealed several genes exhibiting elevated transcript levels in tumors harboring mutant p53. Of these, ARF6, C1QBP, and TRIM23 were studied further. Reverse transcription-quantitative PCR (RT-qPCR) performed on RNA isolated from ESCC tumors revealed significant correlation of TP53 transcript levels with those of the three target genes. Ectopic expression of wild-type and several mutant p53 forms followed by RT-qPCR, chromatin affinity-purification (ChAP), and promoter-luciferase assays indicated the exclusive recruitment of p53 mutants-P190T and P278L, to the target genes leading to the activation of expression. Several functional assays following knockdown of the target genes revealed a significant suppression of tumorigenicity in squamous carcinoma cell lines. Rescue experiments confirmed the specificity of the knockdown. The tumorigenic effects of the genes were confirmed in nude mice xenograft assays. This study has therefore identified novel oncogenic targets of "non-hotspot" mutant p53 proteins relevant for ESCC besides validating the functional heterogeneity of the spectrum of tumor-specific p53 mutations.

Nab-Paclitaxel in the Treatment of Gastrointestinal Cancers-Improvements in Clinical Efficacy and Safety

Taxanes (paclitaxel and docetaxel) are one of the most useful classes of anticancer drugs. Taxanes are highly hydrophobic; therefore, these drugs must be dissolved in organic solvents (polysorbate or Cremophor EL), which contribute to their toxicities. To reduce this toxicity and to enhance their efficacy, novel formulations have been developed. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is an albumin-stabilized, Cremophor-free, and water-soluble nanoparticle formulation of paclitaxel. Nab-paclitaxel has better solubility and less infusion-associated toxicity compared to solvent-based paclitaxel. Additionally, nab-paclitaxel can be given at higher doses and concentrations compared with solvent-based paclitaxel. Based on its superior clinical efficacy and safety profile, nab-paclitaxel received FDA approval for metastatic breast cancer (2008) and NSCLC (2011). Among gastrointestinal cancers, it is now approved in the USA for treating patients with metastatic adenocarcinoma of the pancreas as first-line therapy in combination with gemcitabine. Furthermore, several clinical trials have suggested the potential efficacy of nab-paclitaxel as a single agent or in combination with other agents for the treatment of metastatic esophageal, gastric, bowel, and biliary tract cancers. Nab-paclitaxel has been demonstrated to have greater overall response rates (ORR) with enhanced progression-free survival (PFS), overall survival (OS) and a superior safety profile with fewer adverse effects in patients with gastrointestinal tract cancers. This review summarizes the advantages associated with nab-paclitaxel-based regimens in terms of improving clinical efficacy and the safety profile in upper gastrointestinal cancer.

Adenosquamous Carcinomas and Mucinous Adenocarcinoma of the Minor Salivary Glands: Immunohistochemical and Molecular Insights

There is confusion about the diagnosis, histogenesis and taxonomical efforts regarding adenosquamous carcinomas (ASCs) and mucinous adenocarcinomas (MACs), especially with calls for reconsidering the nature of high-grade mucoepidermoid carcinoma (MEC). This study aims to compare the genetic profiles of ASCs and MACs that have been previously reported in the literature and investigate if either ASC or MAC is closer in genetic mutations to high-grade MEC. Systematic searches in the NCBI, Web of Science, and Scopus databases were performed between January 2000 and August 2022. The retrieved genetic mutations were processed and annotated. Protein–protein network analysis was conducted for each neoplasm. The results were viewed and discussed in terms of molecular oncogenesis of ASCs and MACs at different topographies. Molecular profile mapping was conducted by annotating all the retrieved genes for each neoplasm using genetic network analysis (Cystoscape software program). The genetic profile of each lesion was compared to that of high-grade MEC. To conclude, both genetic profiles do not tend to intersect specifically with high-grade MEC, except for the generic mutations commonly detected in all high-grade head and neck tumors. However, the availability of data on the molecular profile of each lesion limits the generalizability of the findings of this study.

Therapeutic Potential of the Cyclin-Dependent Kinase Inhibitor Flavopiridol on c-Myc Overexpressing Esophageal Cancer

Tumors with elevated c-Myc expression often exhibit a highly aggressive phenotype, and c-Myc amplification has been shown to be frequent in esophageal cancer. Emerging data suggests that synthetic lethal interactions between c-Myc pathway activation and small molecules inhibition involved in cell cycle signaling can be therapeutically exploited to preferentially kill tumor cells. We therefore investigated whether exploiting elevated c-Myc expression is effective in treating esophageal cancer with the CDK inhibitor flavopiridol. We found frequent overexpression of c-Myc in human esophageal cancer cell lines and tissues. c-Myc overexpression correlated with accelerated esophageal cancer subcutaneous xenograft tumor growth. Esophageal cancer cells with elevated c-Myc expression were found preferentially more sensitive to induction of apoptosis by the CDK inhibition flavopiridol compared to esophageal cancer cells with lower c-Myc expression. In addition, we observed that flavopiridol alone or in combination with the chemotherapeutic agent nanoparticle albumin-bound paclitaxel (NPT) or in combinations with the targeted agent BMS-754807 significantly inhibited esophageal cancer cell proliferation and subcutaneous xenograft tumor growth while significantly enhancing overall mice survival. These results indicate that aggressive esophageal cancer cells with elevated c-Myc expression are sensitive to the CDK inhibitor flavopiridol, and that flavopiridol alone or in combination can be a potential therapy for c-Myc overexpressing esophageal cancer.

Occurrence of High Microsatellite-Instability/Mismatch Repair Deficiency in Nearly 2,000 Human Adenocarcinomas of the Gastrointestinal Tract, Pancreas, and Bile Ducts: A Study From a Large German Comprehensive Cancer Center

INTRODUCTION

Knowledge of the high microsatellite-instability (MSI-H)/mismatch repair deficiency (MMRd) status is of increasing interest for personalized neoadjuvant or adjuvant therapy planning. Only a few studies are available on MSI-H distribution in the Northern European Caucasian patient population. In this study, we focused on a large cohort of tumors of the upper gastrointestinal tract.

MATERIALS AND METHODS

Surgical material from a total of 1,965 patients was analyzed for MSI-H/MMRd status (including 1,267 carcinomas of the esophagus or stomach). All tumors were analyzed with an internationally recommended immunohistochemical panel consisting of four antibodies (MLH1, MSH2, PMS2, and MSH6). The results were molecularly objectified.

RESULTS

Adenocarcinomas with MSI-H/MMRd were detected with the following distribution: esophagus (1.4%), stomach (8.3%), small intestine (18.2%), large intestine (8.5%), intrahepatic bile ducts (1.9%), and pancreas (0%). In case of gastric tumors with MSI-H/MMRd, neoadjuvant therapy did not influence the prognosis of patients (p = 0.94). Within all tumor entities with MSI-H/MMRd, patients with a UICC stage 4 were also represented. In this advanced stage, 11.7% of patients with MSS tumors were diagnosed compared to 0.5% of patients with MSI-H tumors relative to the entire tumor collective.

DISCUSSION

In this study, the proportion of MSI-H/MMRd tumors in the stomach is smaller than would have been expected in knowledge of the data published by TCGA or AGRC. Negative prognostic effects regarding MSI-H status and neoadjuvant therapy as described by the MAGIC study group were not seen in our cohort. The extent to which the MSI-H/MMRd status should be known for neoadjuvant therapy planning must be clarified in prospective studies in the future. At present, there is no convincing data to dispense the neoadjuvant therapy for gastric carcinoma. Due to the very convincing, positive data regarding the response rates of MSI-H tumors to treatment with PD1/PD-L1 inhibitors, every metastatic carcinoma of the gastrointestinal tract should be tested for its MSI-H status.

Potential Role of Targeting KDR and Proteasome Inhibitors in the Therapy of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancer types in China. In recent years, progress has been made in various types of cancer genomics including ESCC. However, the clinical significance of genomic variation of ESCC remains poorly defined. In the present study, genomic sequencing data from 469 ESCC cases were analyzed and potential therapeutic targets in the Druggable Genome Interaction Database (DGIdb) were screened. A series of potential therapeutic target genes and pathways were identified, of which treatment of ESCC with bortezomib (a specific inhibitor targeting proteasome) potently inhibited the proliferation of 5 ESCC cell lines and administration of bortezomib led to significant tumor xenograft regression in SCID mice. It was also identified that kinase insert domain receptor (KDR), which had drug recommendations from all 6 sources integrated by the DGldb and harbored significant amplification in ESCC, might be a downstream target of zinc finger protein 750 (ZNF750). ZNF750 acts as a transcription factor and has been demonstrated to harbor frequently inactivating mutations in ESCC by previous independent studies. In the present study, KDR was upregulated upon ZNF750 knockdown and the rescue of ZNF750 also led to marked restoration of KDR. KDR knockdown in stable ZNF750-knockdown KYSE150 and KYSE140 ESCC cells significantly attenuated the promotion of cell growth, colony formation, invasion and migration induced by ZNF750 knockdown. Further experiments found that apatinib treatment, a potent inhibitor of KDR, resulted in profound inhibition of cell proliferation and invasion. Collectively, the present study provided insight for genomic alterations as potential therapeutic targets in ESCC and supported the possibility of a therapeutic strategy targeting the proteasome in ESCC. The present results also suggested that targeting KDR may be an effective way to treat ESCC, not only in KDR variant cases, but also in individuals with ZNF750 mutations and deletions.

Combination effect of lapatinib with foretinib in HER2 and MET co-activated experimental esophageal adenocarcinoma

Recent studies have demonstrated that HER2 and MET receptor tyrosine kinases are co-overexpressed in a subset esophageal adenocarcinoma (EAC). We therefore studied the usefulness of combining HER2 and MET targeting by small-molecule inhibitors lapatinib and foretinib, respectively, both in in-vitro and in-vivo models of experimental EAC. We characterized MET and HER2 activation in a panel of human EAC cell lines, and the differential susceptibility of these EAC cell lines to single agent or combination of foretinib and lapatinib. We then explored the antitumor efficacy with survival advantage following foretinib and lapatinib monotherapy and in combination in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC. The OE33 EAC cell line with strong expression of phosphorylated both MET and HER2, demonstrated reduced sensitivity to foretinib and lapatinib when used as a single agent. The co-administration of foretinib and lapatinib effectively inhibited both MET and HER2 phosphorylation, enhanced inhibition of cell proliferation and xenograft tumor growth by inducing apoptosis, and significantly enhanced mouse overall survival, overcoming single agent resistance. In the OE19 EAC cell line with mainly HER2 phosphorylation, and the ESO51 EAC cell line with mainly MET phosphorylation, profound cell growth inhibition with induction of apoptosis was observed in response to single agent with lack of enhanced growth inhibition when the two agents were combined. These data suggest that combination therapy with foretinib and lapatinib should be tested as a treatment option for HER2 positive patients with MET-overexpressing EAC, and could be a novel treatment strategy for specific EAC patients.

Identification of Adenosquamous Carcinoma as a Rare Aggressive HER2-negative Subgroup of Esophageal/Gastroesophageal Junction Adenocarcinoma

BACKGROUND

Our purpose was to evaluate the prognostic impact of pathologically confirmed esophageal adenosquamous carcinoma (ASC) and its association with HER2 status and clinicopathologic characteristics.

METHODS

Among 796 patients with esophageal or gastroesophageal junction adenocarcinoma who underwent curative resection, surgical pathology reports were reviewed, and suspected ASC was confirmed utilizing p63 and CK5/6 immunostaining. HER2 status was determined using immunohistochemistry and fluorescence in situ hybridization. Cox models were used to assess the impact of ASC on disease-specific survival and overall survival.

RESULTS

Overall, 2.0% (16/796) of patients had esophageal ASC, mostly demonstrating a close intermingling of squamous and adenocarcinoma cells within the same tumor. The percentage of squamous versus adenocarcinoma cells in the primary was generally recapitulated in nodal metastases, and intrapatient internodal heterogeneity was uncommon. Patients with esophageal ASC were statistically significantly more likely to be female (vs. male), have normal (vs. excess) body mass index, and harbor HER2-negative (vs. positive) tumors, as compared with patients with adenocarcinoma only. No ASC tumor was HER2-positive as compared with 16% of adenocarcinoma only tumors (P=0.018). Compared with patients with adenocarcinoma only, those with ASC demonstrated profoundly worse disease-specific survival (5-year event-free rate, 34% vs. 6%; multivariate hazard ratio, 2.87 [95% confidence interval, 1.59-4.76]; P=0.0010) and overall survival (P=0.0027) that was independent of known prognostic factors and HER2 status.

CONCLUSION

ASC identifies a rare aggressive HER2-negative subgroup of esophageal/gastroesophageal junction adenocarcinoma.

Epstein-Barr virus and mismatch repair deficiency status differ between oesophageal and gastric cancer: A large multi-centre study

BACKGROUND

Oesophageal (OeC) and gastric (GC) cancer patients are treated with similar multimodal therapy and have poor survival. There remains an urgent clinical need to identify biomarkers to individualise patient management and improve outcomes. Therapy with immune checkpoint inhibitors has shown promising results in other cancers. Proposed biomarkers to predict potential response to immune checkpoint inhibitors include DNA mismatch repair (MMR) and/or Epstein-Barr virus (EBV) status. The aim of this study was to establish and compare EBV status and MMR status in large multi-centre series of OeC and GC.

METHODS

EBV was assessed by EBV-encoded RNA (EBER) in situ hybridisation and MMR protein expression by immunohistochemistry (IHC) in 988 OeC and 1213 GC from multiple centres. In a subset of OeC, microsatellite instability (MSI) was tested in parallel with MMR IHC.

RESULTS

Frequency of MMR deficiency (MMRdef) and MSI was low in OeC (0.8% and 0.6%, respectively) compared with GC (10.3%). None of the OeCs were EBER positive in contrast to 4.8% EBER positive GC. EBV positive GC patients were younger (p = 0.01), more often male (p = 0.001) and had a better overall survival (p = 0.012). MMRdef GC patients were older (p = 0.001) and showed more often intestinal-type histology (p = 0.022).

CONCLUSIONS

This is the largest study to date indicating that EBV and MMRdef do not play a role in OeC carcinogenesis in contrast to GC. The potential clinical usefulness of determining MMRdef/EBV status to screen patients for eligibility for immune-targeting therapy differs between OeC and GC patients.

The promise of PD-1 inhibitors in gastro-esophageal cancers: microsatellite instability vs. PD-L1

Preliminary clinical studies of anti-programmed cell death-1 (anti-PD-1) therapy in gastro-esophageal cancers have suggested promising single-agent activity. In patients who received prior treatment for advanced disease, pembrolizumab has been associated with a response rate of 20% in programmed cell death-1 ligand 1 (PD-L1)-positive tumors, and nivolumab with a response rate of 12% in unselected tumors. Both agents yielded a median duration of response lasting ~6-7 months. PD-L1 expression and microsatellite instability (MSI) have emerged as potential predictive markers for PD-1/PD-L1 blockade. PD-L1 expression in tumor cells and in immune cells within the tumor microenvironment has been detected in 14-24% and ~35% of patients with gastro-esophageal cancer, respectively. PD-L1 tumor cell expression appears to be more common in Epstein-Barr virus (EBV)-positive gastric cancers (GCs) and has been associated with an increased density of tumor-infiltrating lymphocytes (TIL). To date, data are too sparse to determine whether PD-L1 expression predicts efficacy of anti-PD-1 therapy in gastro-esophageal cancer, but data from other tumor types have not been consistent regarding its predictive value. MSI occurs in 10-20% of gastro-esophageal cancers and arises from deficient mismatch repair (MMR). MSI is highly correlated with non-synonymous mutation burden, as well as a dense accumulation of TILs. MSI has been associated with improved response to anti-PD-1 therapy in gastrointestinal cancers. Multiple studies are ongoing which examine therapeutic blockade of the PD-1/PD-L1 axis in unselected patients with gastro-esophageal cancer, as well as patients whose tumors express PD-L1 or exhibit MSI. These studies will clarify their activity in this disease and potentially can determine whether identify a strong predictive biomarker can be identified. Checkpoint inhibition is also being studied in combination with curative-intent chemo (radio) therapy and surgery.

Enhancing radiosensitivity of TE1, TE8, and TE 11 esophageal squamous carcinoma cell lines by Hdm2-siRNA targeted gene therapy in vitro

Introduction: Human double minute2 (hdm2) level increases in most human malignancies. Therefore, inhibition of tumor growth and also induction of radiosensitivity may be provided by hdm2 inhibitors. The effects of hdm2-siRNA on hdm2 protein expression, cell apoptosis rate, and radiosensitivity of human esophageal squamous cell carcinoma (ESCC) were studied.

Methods: The hdm2 gene was silenced in TE1, TE8, and TE11 ESCC cell lines using 200nM siRNA by liposomal transfection method followed by irradiation with 0.5, 1, 2, 4, and 6 Gy γ-rays in vitro. The gene expression levels were evaluated by real time PCR and Western Blotting methods. MTT, TUNEL, and also colony forming assays were used to compare the radiosensitivity of the cell lines before and after the treatments.

Results: Hdm2-siRNA reduced the hdm2 protein as compared to the vehicle control and scrambled groups, and also increased the radiation-induced apoptosis especially in TE11 cells. The related dose reduction factors (DRFs) for the silenced TE1, TE8, and TE11 cells calculated to be 1.20, 1.30, and 2.75, respectively.

Conclusion: Increasing radiosensitivity of tumor cells may be provided by silencing the oncogenes.

Increased Wnt Signaling and Reduced Viability in a Neuronal Model of Progranulin-Deficient Frontotemporal Lobar Degeneration

Progranulin (PGRN) deficiency is considered the major cause of frontotemporal lobar degeneration with TDP-43 protein inclusions (FTLD-TDP). Recent work unveiled a relationship between Wnt signaling and PGRN in cellular models of FTLD and cells of patients carrying loss-of-function GRN mutations. This study was undertaken to explore the relationship between PGRN deficit and Wnt signaling in the regulation of survival of GRN knockdown neuroblastoma SH-SY5Y cells (GRN KD). We report here that both canonical and noncanonical Wnt signaling cascades are overactivated in GRN KD cells. We detected increased expression levels of Wnt1 and Wnt5a ligands of the Frizzled receptors, as well as evidence for increased signaling of the Wnt/β-catenin and Wnt/Ca²⁺ cascades in PGRN deficient cells, such as increased nuclear content of β-catenin and higher levels of cyclin D1, or increased levels of the active form of the NFAT1 transcription factor, respectively. Upregulation of either Wnt/β-catenin or Wnt/Ca²⁺ signaling in GRN KD cells leads to the stimulation of BrdU incorporation into DNA, hyperphosphorylation of the pRb family of proteins and reduced cell viability over time. Blocking the Wnt cascades by specific canonical or noncanonical inhibitors of Wnt-dependent signaling, normalized the rate of DNA synthesis, and what it is more important restored the viability of GRN KD cells. Our results suggest an important role of Wnt activation inducing cell cycle disturbance-mediated neuronal loss in the pathogenesis of PGRN deficiency-linked FTLD-TDP. Therefore, it is plausible that modulation of Wnt signaling could be a promising strategy for developing of new disease-modifying treatments for FTLD-TDP.

Metadherin contributes to the pathogenesis of chronic lymphocytic leukemia partially through Wnt/β-catenin pathway

Metadherin (MTDH) is involved in aberrant proliferation, migration, and chemoresistance of tumor cells. It has been demonstrated that it can promote tumor growth by modulation multiple oncogenic signaling pathways. However, MTDH expression, significance, and related mechanism in chronic lymphocytic leukemia (CLL) are still unclear. The objective of this study was to investigate the expression of MTDH in CLL and the involvement of Wnt/β-catenin signaling pathway in MTDH effects. Overexpression of MTDH mRNAs was seen in CLL samples. MTDH expression was associated with Rai stage classification of CLL, and altered levels of β2-MG and lactate dehydrogenase in serum samples from patients. Overexpression of MTDH protein was seen in 87 % of CLL samples. Specific siRNAs inhibited MEC-1 cell growth and enhanced cell apoptosis (P < 0.05). Inhibition of MTDH expression resulted in decreased expression levels of lymphoid enhancer-binding factor 1 (LEF-1), and its downstream target genes c-myc and cyclin D1. And there was a strong correlation between MTDH and LEF-1 protein expression in 14 patients with CLL. The results demonstrate that MTDH is specifically expressed in B cell of CLL and exert a preservative role through activation of Wnt signaling pathway. Our findings indicated that MTDH may be a potential therapeutic target of CLL.

TP53 Pro72 allele is enriched in oral tongue cancer and frequently mutated in esophageal cancer in India

Purpose

The tumor suppressor p53 is known to be inactivated frequently in various cancers. In addition, germline polymorphisms in TP53 are known to affect protein function and influence risk of developing different types of cancers. In this study, we analyzed the association of TP53 Pro72Arg polymorphism with squamous cell carcinoma of oral tongue (SCCOT) and esophagus (ESCC) in India.

Methods

We assessed the distribution of TP53 Pro72Arg polymorphism in one hundred and fifteen and eighty two SCCOT and ESCC patients, respectively, with respect to one hundred and ten healthy controls from the same population. In addition, we analyzed association of the polymorphism with several clinico-pathological and molecular parameters.

Results

Pro72 allele was significantly enriched in SCCOT patients compared to the healthy control group but neither allele was enriched in ESCC. Interestingly, Pro72 allele was preferentially mutated in ESCC which was confirmed by analysis of samples heterozygous for Pro72Arg.

Conclusions

Our study revealed the association of Pro72 allele with SCCOT suggesting the effect of this polymorphism on SCCOT risk. Preferential mutation of Pro72 allele exclusively in ESCC indicates the need for further studies to understand the tissue specific effect of p53 polymorphism.

P53 nuclear stabilization is associated with FHIT loss and younger age of onset in squamous cell carcinoma of oral tongue

BACKGROUND

Squamous cell carcinoma of tongue (SCCT) is expected to harbor unique clinico-pathological and molecular genetic features since a significant proportion of patients are young and exhibit no association with tobacco or alcohol.

METHODS

We determined P53, epidermal growth factor receptor, microsatellite instability, human papilloma virus infection and loss of heterozygosity status at several tumor suppressor loci in one hundred and twenty one oral SCCT (SSCOT) samples and analyzed their association with clinico-pathological features and patient survival.

RESULTS

Our results revealed a significantly higher incidence of p53 nuclear stabilization in early (as against late) onset SCCOT. FHIT loss was significantly associated with p53 nuclear stabilization and the association was stronger in patients with no history of tobacco use. Samples harboring mutation in p53 DNA binding domain or exhibiting p53 nuclear stabilization, were significantly associated with poor survival.

CONCLUSION

Our study has therefore identified distinct features in SCCOT tumorigenesis with respect to age and tobacco exposure and revealed possible prognostic utility of p53.