At the dose of 50 mg/d (4 weeks on, 2 weeks off), sunitinib displays manageable toxicity. Antitumor activity supports further studies in patients with renal cell carcinoma, gastrointestinal, neuroendocrine, and stromal tumors. Future studies may consider including prospective imaging techniques such as high frequency ultrasound to monitor tumor density.

The TGFβ signaling pathway has pleiotropic functions regulating cell growth, differentiation, apoptosis, motility and invasion, extracellular matrix production, angiogenesis, and immune response. TGFβ signaling deregulation is frequent in tumors and has crucial roles in tumor initiation, development and metastasis. TGFβ signaling inhibition is an emerging strategy for cancer therapy. The role of the TGFβ pathway as a tumor-promoter or suppressor at the cancer cell level is still a matter of debate, due to its differential effects at the early and late stages of carcinogenesis. In contrast, at the microenvironment level, the TGFβ pathway contributes to generate a favorable microenvironment for tumor growth and metastasis throughout all the steps of carcinogenesis. Then, targeting the TGFβ pathway in cancer may be considered primarily as a microenvironment-targeted strategy. In this review, we focus on the TGFβ pathway as a target for cancer therapy. In the first part, we provide a comprehensive overview of the roles played by this pathway and its deregulation in cancer, at the cancer cell and microenvironment levels. We go on to describe the preclinical and clinical results of pharmacological strategies to target the TGFβ pathway, with a highlight on the effects on tumor microenvironment. We then explore the perspectives to optimize TGFβ inhibition therapy in different tumor settings.

Rapamycin and its derivatives (CCI-779, RAD001 and AP23576) are immunosuppressor macrolides that block mTOR (mammalian target of rapamycin) functions and yield antiproliferative activity in a variety of malignancies. Molecular characterization of upstream and downstream mTOR signaling pathways is thought to allow a better selection of rapamycin-sensitive tumours. For instance, a loss of PTEN functions results in Akt phosphorylation, cell growth and proliferation; circumstances that can be blocked using rapamycin derivatives. From recent studies, rapamycin derivatives appear to display a safe toxicity profile with skin rashes and mucositis being prominent and dose-limiting. Sporadic activity with no evidence of dose-effect relationship has been reported. Evidence suggests that rapamycin derivatives could induce G1-S cell cycle delay and eventually apoptosis depending on inner cellular characteristics of tumour cells. Surrogate molecular markers that could be used to monitor biological effects of rapamycin derivatives and narrow down biologically active doses in patients, such as the phosphorylation of P70S6K or expression of cyclin D1 and caspase 3, are currently evaluated. Since apoptosis induced by rapamycin is blocked by BCL-2, strategies aimed at detecting human tumours that express BCL-2 and other anti-apoptotic proteins might allow identification of rapamycin-resistant tumours. Finally, we discuss current and future placements of rapamycin derivatives and related translational research into novel therapeutic strategies against cancer.

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INTRODUCTION: Inhibition of tumor growth factor-β (TGF-β) receptor type I potentiated the activity of sorafenib in preclinical models of hepatocellular carcinoma (HCC). Galunisertib is a small-molecule selective inhibitor of TGF-β1 receptor type I, which demonstrated activity in a phase 2 trial as second-line HCC treatment. METHODS: The combination of galunisertib and sorafenib (400 mg BID) was tested in patients with advanced HCC and Child-Pugh A liver function without prior systemic therapy. Galunisertib dose was administered 80 or 150 mg b.i.d. orally for 14 days every 28 days in safety lead-in cohorts; in the expansion cohort, all patients received galunisertib 150 mg b.i.d. Objectives included time-to-tumor progression, changes in circulating alpha fetoprotein and TGF-β1, safety, overall survival (OS), response rate, and pharmacokinetics (PK). RESULTS: Patients (n = 47) were enrolled from 5 non-Asian countries; 3 and 44 patients received the 80 mg and 150 mg b.i.d. doses of galunisertib, respectively. The pharmacokinetics and safety profiles were consistent with monotherapy of each drug. For the 150 mg b.i.d. galunisertib cohort, the median time-to-tumor progression was 4.1 months; the median OS was 18.8 months. A partial response was seen in 2 patients, stable disease in 21, and progressive disease in 13. TGF-β1 responders (decrease of >20% from baseline) vs nonresponders had longer OS (22.8 vs 12.0 months, P = 0.038). DISCUSSION: The combination of galunisertib and sorafenib showed acceptable safety and a prolonged OS outcome.

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of cancer death by 2030. Current therapeutic options are limited, warranting an urgent need to explore innovative treatment strategies. Due to specific microenvironment constraints including an extensive desmoplastic stroma reaction, PDAC faces major metabolic challenges, principally hypoxia and nutrient deprivation. Their connection with oncogenic alterations such as KRAS mutations has brought metabolic reprogramming to the forefront of PDAC therapeutic research. The Warburg effect, glutamine addiction, and autophagy stand as the most important adaptive metabolic mechanisms of cancer cells themselves, however metabolic reprogramming is also an important feature of the tumor microenvironment, having a major impact on epigenetic reprogramming and tumor cell interactions with its complex stroma. We present a comprehensive overview of the main metabolic adaptations contributing to PDAC development and progression. A review of current and future therapies targeting this range of metabolic pathways is provided.