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 Student's 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.

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.

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.

Bevacizumab maintenance in metastatic colorectal cancer: How long?

The management of patients with non-progressive metastatic colorectal cancer after six months of treatment has not yet been codified. The most relevant concerns are the effectiveness of maintenance vs discontinuation, and the tolerability of prolonged treatment. Here we report the case of a 72-year-old man affected by colorectal cancer with lung metastases who achieved a complete response after receiving capecitabine, oxaliplatin and bevacizumab for six months, and bevacizumab alone for six months. Bevacizumab was continued as maintenance regimen for more than three years. It was discontinued because of an arthroplasty. Fifty-eight months after beginning first-line treatment, the patient remains free from relapse. Adverse effects were minimal and easily controlled.

Adjuvant treatment for locally advanced rectal cancer patients after preoperative chemoradiotherapy: when, and for whom?

BACKGROUND: The standard treatment for patients with locally advanced rectal cancer (clinical tumor, node, metastases [TNM] stage II or III) is radiotherapy before surgery (with or without concomitant fluoropyrimidine-based chemotherapy) followed by surgery. The role of adjuvant chemotherapy in this setting of patients is controversial in terms of the overall benefit on survival, the subgroup of patients who might not need it, and the best regimen (combination regimens vs. fluoropyrimidine alone). PATIENTS AND METHODS: Based on the retrospective analysis of the clinical outcome of all patients with locally advanced rectal adenocarcinoma treated at our institute during the past 9 years, we comment on prognostic factors for local and distant metastases of patients who received neoadjuvant treatment followed by surgery, and the scientific evidence that can help to decide the adjuvant chemotherapy. RESULTS: We conclude that pathological TNM stage after neoadjuvant chemoradiation (ypTNM) stage after surgery significantly affects disease-free and overall survival. In particular, patients with pathologically positive lymph nodes (ypN+) after surgery have a high probability of developing distant metastases. CONCLUSION: ypN+ patients are candidate for intensified adjuvant chemotherapy.

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

INTRODUCTION: Src 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. METHODS: To 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. RESULTS: Src 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. CONCLUSIONS: Complete pharmacologic EGFR/HER2 inhibition is required to reverse Src-dependent resistance to lapatinib in breast cancer.

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.

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.

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.

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 (18)F-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.

Primary hepatic lymphoma in a patient with previous rectal adenocarcinoma: a case report and discussion of etiopathogenesis and diagnostic tools.

Primary hepatic lymphoma is an extremely rare malignancy accounting for 0.016% of all cases of non-Hodgkin lymphomas. Approximately 1-4% of histologies described show a follicular pattern. We report a case of primary hepatic non-Hodgkin lymphoma that developed in a middle-aged woman 3 years after radical treatment (neoadjuvant chemoradiotherapy and surgery) for a rectal adenocarcinoma. Abdomen ultrasound showed a single nodule in the liver, which raised the issue of differential diagnosis with a metastasis from rectal cancer. After surgical removal of the nodule, histology revealed a primary B cell, stage IE follicular non-Hodgkin lymphoma, confined to the liver; indeed, no foci of lymphoma were found elsewhere in the body.