Lucia Raimondo

The dual PI3K/mTOR inhibitor PKI-587 enhances sensitivity to cetuximab in EGFR-resistant human head and neck cancer models

Background:Cetuximab is the only targeted agent approved for the treatment of head and neck squamous cell carcinomas (HNSCC), but low response rates and disease progression are frequently reported. As the phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathways have an important role in the pathogenesis of HNSCC, we investigated their involvement in cetuximab resistance.Methods:Different human squamous cancer cell lines sensitive or resistant to cetuximab were tested for the dual PI3K/mTOR inhibitor PF-05212384 (PKI-587), alone and in combination, both in vitro and in vivo.Results:Treatment with PKI-587 enhances sensitivity to cetuximab in vitro, even in the condition of epidermal growth factor receptor (EGFR) resistance. The combination of the two drugs inhibits cells survival, impairs the activation of signalling pathways and induces apoptosis. Interestingly, although significant inhibition of proliferation is observed in all cell lines treated with PKI-587 in combination with cetuximab, activation of apoptosis is evident in sensitive but not in resistant cell lines, in which autophagy is pre-eminent. In nude mice xenografted with resistant Kyse30 cells, the combined treatment significantly reduces tumour growth and prolongs mice survival.Conclusions:Phosphoinositide 3-kinase/mammalian target of rapamycin inhibition has an important role in the rescue of cetuximab resistance. Different mechanisms of cell death are induced by combined treatment depending on basal anti-EGFR responsiveness.

Epidermal growth factor-receptor activation modulates Src-dependent resistance to lapatinib in breast cancer models

IntroductionSrc tyrosine kinase overactivation has been correlated with a poor response to human epidermal growth factor receptor 2 (HER2) inhibitors in breast cancer. To identify the mechanism by which Src overexpression sustains this resistance, we tested a panel of breast cancer cell lines either sensitive or resistant to lapatinib.MethodsTo determine the role of Src in lapatinib resistance, we evaluated the effects of Src inhibition/silencing in vitro on survival, migration, and invasion of lapatinib-resistant cells. In vivo experiments were performed in JIMT-1 lapatinib-resistant cells orthotopically implanted in nude mice. We used artificial metastasis assays to evaluate the effect of Src inhibition on the invasiveness of lapatinib-resistant cells. Src-dependent signal transduction was investigated with Western blot and ELISA analyses.ResultsSrc activation was higher in lapatinib-resistant than in lapatinib-sensitive cells. The selective small-molecule Src inhibitor saracatinib combined with lapatinib synergistically inhibited the proliferation, migration, and invasion of lapatinib-resistant cells. Saracatinib combined with lapatinib significantly prolonged survival of JIMT-1-xenografted mice compared with saracatinib alone, and impaired the formation of lung metastases. Unexpectedly, in lapatinib-resistant cells, Src preferentially interacted with epidermal growth factor receptor (EGFR) rather than with HER2. Moreover, EGFR targeting and lapatinib synergistically inhibited survival, migration, and invasion of resistant cells, thereby counteracting Src-mediated resistance. These findings demonstrate that Src activation in lapatinib-resistant cells depends on EGFR-dependent rather than on HER2-dependent signaling.ConclusionsComplete pharmacologic EGFR/HER2 inhibition is required to reverse Src-dependent resistance to lapatinib in breast cancer.

Mechanisms of lapatinib resistance in HER2-driven breast cancer

Targeted therapies have been approved for various malignancies but the acquisition of resistance remains a substantial challenge in the clinical management of advanced cancers. Twenty-five per cent of breast cancers overexpress ErbB2/HER2, which confers a more aggressive phenotype and is associated with a poor prognosis. HER2-targeting therapies (trastuzumab, pertuzumab, TDM1 and lapatinib) are available, but a significant fraction of HER2-positive breast cancers eventually relapse or progress. This suggests that acquired or intrinsic resistance enables escape from HER2 inhibition. This review focuses on mechanisms of intrinsic/acquired resistance to lapatinib identified in preclinical and clinical studies. A better understanding of these mechanisms could lead to novel predictive markers of lapatinib response and to novel therapeutic strategies for breast cancer patients.

Combination of docetaxel and cetuximab for penile cancer: A case report and literature review

Guidelines on the treatment of metastatic squamous cell carcinoma of the penis are limited to a few prospective trials. Cisplatin-based regimens represent the standard of treatment with promising activity of taxanes. Recently, epidermal growth factor receptor overexpression has been shown in these patients. We treated an elderly man with a docetaxel–cetuximab combination after failure of the cisplatin regimen. We observed a necrosis of the inguinal lymph nodes and a reduction of 18F-fluorodeoxyglucose uptake at PET/CT scan. Only mild mucositis and skin toxicity had been detected. Our case report, the first in the literature, shows that this combination is active and well tolerated in penile squamous cell carcinoma.

Inhibition of Hedgehog signalling by NVP-LDE225 (Erismodegib) interferes with growth and invasion of human renal cell carcinoma cells

Background:Multiple lines of evidence support that the Hedgehog (Hh) signalling has a role in the maintenance and progression of different human cancers. Therefore, inhibition of the Hh pathway represents a valid anticancer therapeutic approach for renal cell carcinoma (RCC) patients. NVP-LDE225 is a Smoothened (Smo) antagonist that induces dose-related inhibition of Hh and Smo-dependent tumour growth.Methods:We assayed the effects of NVP-LDE225 alone or in combination with everolimus or sunitinib on the growth and invasion of human RCC models both in vitro and in vivo. To this aim, we used a panel of human RCC models, comprising cells with acquired resistance to sunitinib – a multiple tyrosine kinase inhibitor approved as a first-line treatment for RCC.Results:NVP-LDE225 cooperated with either everolimus or sunitinib to inhibit proliferation, migration, and invasion of RCC cells even in sunitinib-resistant (SuR) cells. Some major transducers involved in tumour cell motility, including paxillin, were also efficiently inhibited by the combination therapy, as demonstrated by western blot and confocal microscopy assays. Moreover, these combined treatments inhibited tumour growth and increased animal survival in nude mice xenografted with SuR RCC cells. Finally, lung micrometastasis formation was reduced when mice were treated with NVP-LDE225 plus everolimus or sunitinib, as evidenced by artificial metastatic assays.Conclusions:Hedgehog inhibition by NVP-LDE225 plus sunitinib or everolimus bolsters antitumour activity by interfering with tumour growth and metastatic spread, even in SuR cells. Thus, this new evidence puts forward a new promising therapeutic approach for RCC patients.

Src inhibitors act through different mechanisms in Non-Small Cell Lung Cancer models depending on EGFR and RAS mutational status

Resistance to the EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, often related to Ras or secondary EGFR mutations, is a relevant clinical issue in Non-Small Cell Lung Cancer (NSCLC). Although Src TK has been involved in such resistance, clinical development of its inhibitors has been so far limited. To better define the molecular targets of the Src TKIs saracatinib, dasatinib and bosutinib, we used a variety of in vitro/in vivo studies. Kinase assays supported by docking analysis demonstrated that all the compounds directly inhibit EGFR TK variants. However, in live cells only saracatinib efficiently reduced EGFR activation, while dasatinib was the most effective agent in inhibiting Src TK. Consistently, a pronounced anti-proliferative effect was achieved with saracatinib, in EGFR mutant cells, or with dasatinib, in wt EGFR/Ras mutant cells, poorly dependent on EGFR and erlotinib-resistant. We then identified the most effective drug combinations to overcome resistance to EGFR inhibitors, both in vitro and in nude mice: in T790M EGFR erlotinib-resistant cells, saracatinib with the anti-EGFR mAb cetuximab; in Ras mutant erlotinib-resistant models, dasatinib with the MEK inhibitor selumetinib. Src inhibitors may act with different mechanisms in NSCLCs, depending on EGFR/Ras mutational profile, and may be integrated with EGFR or MEK inhibitors for different cohorts of NSCLCs.

FOLFIRI in patients with locally advanced or metastatic pancreatic or biliary tract carcinoma: A monoinstitutional experience

Pancreatic and biliary tract carcinomas are very chemoresistant. After a first-line treatment with a gemcitabine-based regimen, no second-line scheme is consolidated in clinical practice. The aim of this study was to evaluate the toxicity and the activity of the FOLFIRI regimen as first-line or second-line chemotherapy in patients with pancreatic or biliary tract tumors. Fifty-four patients (30 with pancreatic tumor, nine with gallbladder tumor, and 15 with biliary tract tumor) were treated with FOLFIRI (irinotecan 180 mg/m2, day 1; leucovorin 100 mg/m2 intravenously, days 1 and 2; 5-fluorouracil 400 mg/m2 intravenous bolus, days 1 and 2; and 600 mg/m2 in 22 h intravenously, continuous infusion days 1 and 2; every 14 days). Toxicity was recorded at each cycle according to the NCI-CTC V3.0 criteria, the response rate was verified each four cycles according to the RECIST criteria, and the progression-free survival rates as well as the overall survival rates were calculated according to the Kaplan–Meier method. Overall, the toxicity was mild. Grade 3–4 neutropenia occurred in 42.6% of patients. Grade 3–4 gastrointestinal toxicity was rare. FOLFIRI as a first-line treatment produced a response rate of 25%. In the second-line group, 9/21 patients (42.9%) obtained a stable disease as best response. In the entire population, the median progression-free survival rates were 3.1 months [95% confidence interval (CI), 1.9–4.4] and 3.5 months (95% CI, 2.6–4.4), respectively, in the first-line and the second-line cohort of patients. The median overall survival rates were 14.5 months (95% CI, 7.0–22.1) and 6.2 months (95% CI, 5.4–7.0), respectively, in the first-line and the second-line cohort of patients. FOLFIRI is feasible and well tolerated in patients with pancreatic or biliary tract tumors; it has a good activity in first line and mostly in patients with pancreatic cancer.

Everolimus induces Met inactivation by disrupting the FKBP12/Met complex

Inhibition of the mechanistic target of rapamycin (mTOR) is a promising treatment strategy for several cancer types. Rapamycin derivatives such as everolimus are allosteric mTOR inhibitors acting through interaction with the intracellular immunophilin FKBP12, a prolyl isomerase with different cellular functions. Although mTOR inhibitors have significantly improved survival of different cancer patients, resistance and lack of predictive factors of response remain unsolved issues. To elucidate the mechanisms of resistance to everolimus, we evaluated Met activation in everolimus-sensitive/resistant human cancer cells, in vitro and in vivo. Biochemical and computational analyses were performed. Everolimus-resistant cells were xenografted into mice (10/group) and studied for their response to everolimus and Met inhibitors. The statistical significance of the in vitro results was evaluated by Students t test. Everolimus reduced Met phosphorylation in everolimus-sensitive cells. This event was mediated by the formation of a Met-FKBP12 complex, which in turn is disrupted by everolimus. Aberrant Met activation in everolimus-resistant cells and overexpression of wild-type/mutant Met caused everolimus resistance. Pharmacological inhibition and RNA silencing of Met are effective in condition of everolimus resistance (P<0.01). In mice xenografted with everolimus-resistant cells, the combination of everolimus with the Met inhibitor PHA665752 reduced tumor growth and induced a statistically significant survival advantage (combination vs control P=0.0005). FKBP12 binding is required for full Met activation and everolimus can inhibit Met. Persistent Met activation might sustain everolimus resistance. These results identify a novel everolimus mechanism of action and suggest the development of clinical strategies based on Met inhibitors in everolimus-resistant cancers.

Basaloid Squamous Cell Carcinoma: A Rare Tumor at the Esophagogastric Junction and an Unexpected Durable Complete Response to FOLFOX-4

Background: Basaloid squamous cell carcinoma (BSCC) is a high-grade variant of squamous cell carcinoma usually localized in the aerodigestive tract, with a poor prognosis. Surgical resection is generally recommended, even if no standard treatment has been established yet. Case Report: Here, we report the case history of a patient diagnosed with BSCC at the esophagogastric junction who was successfully treated with chemotherapy alone, leading to a durable complete response. Conclusions: The presented case illustrates the diagnostic challenges associated with BSCC of the esophagus and reports an unexpected chemosensitivity of this histotype to the combination of a platinum salt plus 5-fluorouracil, which could represent an optimal treatment strategy in unfit patients.

Tumor-to-tumor metastasis: Breast cancer metastatic to thymic epithelial tumor

Tumor-to-tumor metastasis is a rare phenomenon, with around 150 cases being reported in the literature. Breast cancer is the second most commonly reported donor tumor after lung cancer, but thymic epithelial tumors have never been reported as recipient tumors. Furthermore, the thymus is rarely affected by metastases. To our knowledge, the present report is the first case of breast cancer metastatic to thymic epithelial tumor.