Matthew H. Wong

Cotargeting of Epidermal Growth Factor Receptor and PI3K Overcomes PI3K–Akt Oncogenic Dependence in Pancreatic Ductal Adenocarcinoma

Purpose: PI3K–Akt is overexpressed in 50% to 70% of pancreatic ductal adenocarcinoma (PDAC). The hypothesis of this study is that PI3K and EGFR coinhibition may be effective in PDAC with upregulated PI3K–Akt signaling. Experimental Design: Multiple inhibitors were tested on five PDAC cell lines. EGFR inhibitor (EGFRi)–resistant cell lines were found to have significantly overexpressed AKT2 gene, total Akt, and pAkt. In vitro erlotinib-resistant (ER) cell models (BxPC-ER and PANC-ER) with highly constitutively active PI3K–Akt were developed. These and their respective parent cell lines were tested for sensitivity to erlotinib, IGFIR inhibitor NVP-AEW541 (AEW), and PI3K-alpha inhibitor NVP-BYL719 (BYL), alone or in combination, by RTK-phosphoarray, Western blotting, immunofluorescence, qRT-PCR, cell proliferation, cell cycle, clonogenic, apoptosis, and migration assays. Erlotinib plus BYL was tested in vivo. Results: Erlotinib acted synergistically with BYL in BxPC-ER (synergy index, SI = 1.71) and PANC-ER (SI = 1.44). Treatment of ER cell lines showing upregulated PI3K–Akt with erlotinib plus BYL caused significant G1 cell-cycle arrest (71%, P < 0.001; 58%, P = 0.003), inhibition of colony formation (69% and 72%, both P < 0.001), and necrosis and apoptosis (75% and 53%, both P < 0.001), more so compared with parent cell lines. In primary patient-derived tumor subrenal capsule (n = 90) and subcutaneous (n = 22) xenografts, erlotinib plus BYL significantly reduced tumor volume (P = 0.005). Strong pEGFR and pAkt immunostaining (2+/3+) was correlated with high and low responses, respectively, to both erlotinib and erlotinib plus BYL. Conclusion: PDAC with increased expression of the PI3K–Akt pathway was susceptible to PI3K–EGFR coinhibition, suggesting oncogenic dependence. Erlotinib plus BYL should be considered for a clinical study in PDAC; further evaluation of pEGFR and pAkt expression as potential positive and negative predictive biomarkers is warranted. Clin Cancer Res; 20(15); 4047–58. ©2014 AACR.

Upstream and Downstream Co-inhibition of Mitogen-Activated Protein Kinase and PI3K/Akt/mTOR Pathways in Pancreatic Ductal Adenocarcinoma

BACKGROUND: Extensive cross talk exists between PI3K/Akt/mTOR and mitogen-activated protein kinase (MAPK) pathways, and both are upregulated in pancreatic ductal adenocarcinoma (PDAC). Our previous study suggested that epidermal growth factor receptor inhibitor erlotinib which acts upstream of these pathways acts synergistically with PI3K inhibitors in PDAC. Horizontal combined blockade upstream and downstream of these two pathways is therefore explored. METHODS: Erlotinib paired with PI3K inhibitor (BYL719) was tested against erlotinib plus dual PI3K/mTOR inhibitor BEZ-235, and MEK inhibitor (PD98059) plus BEZ235, on five primary PDAC cell lines and on two pairs of parent and erlotinib-resistant (ER) cell lines. A range of in vitro assays including cell proliferation, Western blotting, migration, clonogenic, cell cycle, and apopotic assays was used to test for the efficacy of combined blockade. RESULTS: Dual downstream blockade of the MAPK and PAM pathways was more effective in attenuating downstream molecular signals. Synergy was demonstrated for erlotinib and BEZ235 and for PD-98059 and BEZ-235. This resulted in a trend of increased growth cell cycle arrest, apoptosis, cell proliferation, and colony and migration suppression. This combination showed more efficacy in cell lines with acquired resistance to erlotinib. CONCLUSIONS: The additional mTOR blockade provided by BEZ235 in combined blockade resulted in increased anticancer effect. The hypersensitivity of ER cell lines to additional mTOR blockade suggested PAM pathway oncogenic dependence via mTOR. Dual downstream combined blockade of MAPK and PAM pathways with MEK and PI3K/mTOR inhibitor appeared most effective and represents an attractive therapeutic strategy against pancreatic cancer and its associated drug resistance.

Pulmonary Interstitial Amyloidosis Complicating Multiple Myeloma

phoma of mucosa-associated lymphoid tissue (MALT) type. Due to positive surgical margins, she was treated with 3Dconformal radiation therapy to the pelvic area using 18 MV photons to 30.6 Gy in 17 fractions. She also received four weekly infusions of rituximab (anti-CD20 monoclonal antibody). She tolerated treatment well and finished without complications. At 28 months followup, she was still asymptomatic and free of disease. Primary lymphoma of the cervix is a rare malignancy with follicular and diffuse large-cell lymphoma being the most common types. MALT lymphoma is a distinctive extranodal marginal zone B-cell lymphoma, which is most commonly seen in the GI tract (an estimated 60% to 70% of MALT lymphomas occur inside the GI tract), followed by the orbit, salivary glands, lung, and skin. Less commonly it is seen in the thyroid, breast, liver, bladder, and other tissues. MALT lymphomas typically occur in the setting of infection, such as with H pylori infection in the stomach, or in the setting of autoimmune disorders, such as with Sjogren’s syndrome in the salivary glands. It has been speculated that the cervix, with its endocervical columnar epithelium and acidic mucous layer, might provide a suitable environment for H pylori, but studies have failed to detect its presence in the cervix of patients with cervicitis, and our stain for it was negative. Diagnosis can be difficult because of coexistence of an inflammatory lymphoid infiltrate as seen in this patient. MALT lymphoma is often highly responsive to radiotherapy, with doses of 25 Gy to 35 Gy leading to local control rates of up to 95%. Relapse may occur in up to 40% of patients, most often distant from the original site. While randomized trials of CD20 antibody therapy for nongastrointestinal MALT lymphomas have not been conducted, its use has been reported in numerous cases, especially for tumors refractory to other treatment. In a study of 35 patients, 20 of whom had nongastric MALT lymphoma, CD20 antibody therapy had a 73% response rate. There has been only one previous case reported of a typical low-grade MALT lymphoma of the cervix. Interestingly, the preoperative diagnosis in that case was also fibroid tumor with lymphoma being confirmed in the final surgical specimen. Clinicians should be aware that seemingly benign cervical masses have the potential to be MALT lymphomas that can be effectively treated with local surgery and/or radiation.

Systematic Review and Meta-Analysis on the Role of Chemotherapy in Advanced and Metastatic Neuroendocrine Tumor (NET).

Background/Objectives In the era of somatostatin analogues and targeted therapies, the role of chemotherapy in NET remains largely undefined. This systematic review aimed to assess the effect of chemotherapy on response rates (RR), progression-free survival (PFS), overall survival (OS) and toxicity compared to other chemotherapies/systemic therapies or best supportive care in patients with advanced or metastatic NET. Methods Randomised controlled trials (RCTs) from 1946 to 2015 were identified from MEDLINE, EMBASE, other databases and conference proceedings. Review of abstracts, quality assessment and data abstraction were performed independently by two investigators. Meta-analyses were conducted using Mantel-Haenszel analysis with random-effects modelling. Results Six RCTs comparing standard streptozotocin plus 5-fluorouacil (STZ/5FU) chemotherapy to other chemotherapy regimens, and 2 comparing this to interferon (IFN) were included. Only 1 study was considered at low risk of bias. STZ/5-FU was no different to other chemotherapies in response rate [RR 0.96; 95% confidence interval (CI) 0.72–1.27], PFS (RR 0.95; CI 0.81–1.13), or OS (RR 1.03; CI 0.77–1.39). IFN may produce higher response than STZ/5FU (RR 0.20; CI 0.04–1.13), but event rates were small and survival was no different. Interferon was associated with higher overall haematological (RR 0.47; CI 0.27–0.82) and lower overall renal toxicity (RR 3.61; CI 1.24–10.51). Conclusion Strong evidence is lacking in the area of chemotherapy in neuroendocrine tumors. There is currently no evidence that one chemotherapeutic regimen is significantly better than the other, nor is interferon better than chemotherapy. There is an urgent need to design RCTs comparing modern chemotherapy to other agents in NET.

Systematic Review of the Role of Targeted Therapy in Metastatic Neuroendocrine Tumors

Background: Targeted therapies [interferon (IFN), vascular endothelial growth factor (VEGF) inhibitors, and somatostatin analogs (SSA)] have become an integral part of the neuroendocrine tumor (NET) treatment paradigm. We systematically reviewed the available literature to assess the overall beneficial and negative effects of targeted therapy on progression-free survival (PFS), overall survival (OS), response rate (RR), and toxicity. Methods: Randomized controlled trials (RCT) were identified from MEDLINE, Embase, other major databases, and an electronic search of major conferences. Abstract review, quality assessment, and data abstraction were performed independently by 2 investigators. Meta-analyses were conducted using the generic inverse variance method with a random-effects model, with studies pooled according to drug class and/or control arm for clinical homogeneity. Results: Fifteen RCT [SSA, n = 2; mammalian target of rapamycin (mTOR)/VEGF inhibitors, n = 4; IFN, n = 3; targeted therapy added to everolimus, n = 2, and other, n = 4] investigating 2,790 patients were included. Overall, targeted agents improved PFS (HR 0.54; 95% CI 0.40-0.73) but not OS (HR 0.86; 95% CI 0.72-1.01). SSA improved PFS (HR 0.41; 95% CI 0.29-0.58) but not OS (HR 1.00; 95% CI 0.58-1.74). mTOR/VEGF inhibitors improved PFS (HR 0.48; 95% CI 0.32-0.72) but not OS (HR 0.82; 95% CI 0.58-1.17). Targeted therapies added to everolimus or IFN did not improve either PFS or OS. The RR overall was improved (OR 2.85; 95% CI 1.77-4.59) but toxicity was increased (meta-analysis not performed). Conclusions: The addition of targeted therapies improves PFS but not OS in NET. The evidence is strongest for VEGF inhibitors and SSA. There is an ongoing need for well-designed RCT to inform the optimal use of targeted therapies in NET.