Treatment response lowers tumor symptom burden in recurrent and/or metastatic head and neck cancer.

BACKGROUND: Head and neck squamous cell cancer (HNSCC) frequently causes severe symptoms that may be reduced, when the tumor is successfully treated. The SOCCER trial studied the association of treatment response with patient reported tumor symptom burden in first line treatment of recurrent and/or metastatic HNSCC. METHODS: In this prospective, multi-center, non-interventional trial patients were treated either with platinum-based chemotherapy and cetuximab or radiotherapy and cetuximab. Tumor symptom burden was assessed every four weeks with a questionnaire containing ten visual analogue scales (VAS, range 0-100), which were summarized to the overall VAS score. RESULTS: Fourhundred seventy patients were registered in 97 German centers. A total of 315 patients with at least the baseline and one subsequent questionnaire were available for analysis. Changes in the VAS score were rated as absolute differences from baseline. Negative values indicate improvement of symptoms. The overall VAS score improved significantly at the first post-baseline assessment in responders (- 2.13 vs. non-responders + 1.15, p = 0.048), and even more for the best post-baseline assessment (- 7.82 vs. non-responders - 1.97, p = 0.0005). The VAS for pain (- 16.37 vs. non-responders - 8.89, p = 0.001) and swallowing of solid food (- 16.67 vs. non-responders - 5.06, p = 0.002) improved significantly more in responders (best post-baseline assessment). In the multivariable Cox regression analysis, worse overall VAS scores were associated with worse overall survival (hazard ratio for death 1.12 per 10 points increment on the overall VAS scale, 95% CI 1.05-1.20, p = 0.0009). CONCLUSION: In unselected patients beyond randomized controlled trials, treatment response lowers tumor symptom burden in recurrent and/or metastatic HNSCC. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00122460 . Registered 22 Juli 2005.

Starvation-induced activation of ATM/Chk2/p53 signaling sensitizes cancer cells to cisplatin.

BACKGROUND: Optimizing the safety and efficacy of standard chemotherapeutic agents such as cisplatin (CDDP) is of clinical relevance. Serum starvation in vitro and short-term food starvation in vivo both stress cells by the sudden depletion of paracrine growth stimulation. METHODS: The effects of serum starvation on CDDP toxicity were investigated in normal and cancer cells by assessing proliferation, cell cycle distribution and activation of DNA-damage response and of AMPK, and were compared to effects observed in cells grown in serum-containing medium. The effects of short-term food starvation on CDDP chemotherapy were assessed in xenografts-bearing mice and were compared to effects on tumor growth and/or regression determined in mice with no diet alteration. RESULTS: We observed that serum starvation in vitro sensitizes cancer cells to CDDP while protecting normal cells. In detail, in normal cells, serum starvation resulted in a complete arrest of cellular proliferation, i.e. depletion of BrdU-incorporation during S-phase and accumulation of the cells in the G0/G1-phase of the cell cycle. Further analysis revealed that proliferation arrest in normal cells is due to p53/p21 activation, which is AMPK-dependent and ATM-independent. In cancer cells, serum starvation also decreased the fraction of S-phase cells but to a minor extent. In contrast to normal cells, serum starvation-induced p53 activation in cancer cells is both AMPK- and ATM-dependent. Combination of CDDP with serum starvation in vitro increased the activation of ATM/Chk2/p53 signaling pathway compared to either treatment alone resulting in an enhanced sensitization of cancer cells to CDDP. Finally, short-term food starvation dramatically increased the sensitivity of human tumor xenografts to cisplatin as indicated not only by a significant growth delay, but also by the induction of complete remission in 60% of the animals bearing mesothelioma xenografts, and in 40% of the animals with lung carcinoma xenografts. CONCLUSION: In normal cells, serum starvation in vitro induces a cell cycle arrest and protects from CDDP induced toxicity. In contrast, proliferation of cancer cells is only moderately reduced by serum starvation whereas CDDP toxicity is enhanced. The combination of CDDP treatment with short term food starvation improved outcome in vivo. Therefore, starvation has the potential to enhance the therapeutic index of cisplatin-based therapy.

A Prospective Real-World Multi-Center Study to Evaluate Progression-Free and Overall Survival of Radiotherapy with Cetuximab and Platinum-Based Chemotherapy with Cetuximab in Locally Recurrent Head and Neck Cancer.

Treatment options of locoregional recurrent head and neck squamous cell cancer (HNSCC) include both local strategies as surgery or re-radiotherapy and systemic therapy. In this prospective, multi-center, non-interventional study, patients were treated either with platinum-based chemotherapy and cetuximab (CT + Cet) or re-radiotherapy and cetuximab (RT + Cet). In the current analysis, progression-free survival (PFS) and overall survival (OS) were compared in patients with locoregional recurrence. Four hundred seventy patients were registered in 97 German centers. After exclusion of patients with distant metastases, a cohort of 192 patients was analyzed (129 CT + Cet, 63 RT + Cet). Radiotherapy was delivered as re-irradiation to 70% of the patients. The mean radiation dose was 51.8 Gy, whereas a radiation dose of ≥60 Gy was delivered in 33% of the patients. Chemotherapy mainly consisted of cisplatin/5-flurouracil (40%) or carboplatin/5-flurouracil (29%). The median PFS was 9.2 months in the RT + Cet group versus 5.1 months in the CT + Cet group (hazard ratio for disease progression or death, 0.40, 95% CI, 0.27-0.57, p < 0.0001). Median OS was 12.8 months in the RT + Cet group versus 7.9 months in the CT + Cet group (hazard ratio for death, 0.50, 95% CI, 0.33-0.75, p = 0.0008). In conclusion, radiotherapy combined with cetuximab improved survival compared to chemotherapy combined with cetuximab in locally recurrent HNSCC.

Role of the microenvironment for radiosensitization by patupilone.

PURPOSE: The combined treatment modality of ionizing radiation (IR) and the clinically relevant microtubule-stabilizing compound patupilone (epothilone B, EPO906) is a promising approach for anticancer therapy. Here, we investigated the role of the tumor microenvironment for the supra-additive in vivo response in tumor xenografts derived from patupilone-sensitive and patupilone-resistant non-small cell lung cancer cells. EXPERIMENTAL DESIGN: The treatment response to a combined regimen of patupilone and IR was investigated in vitro and in tumor xenografts derived from wild-type A549 and A549.EpoB40 cells, which are resistant to patupilone due to a beta-tubulin mutation. RESULTS: In both A549 and A549.EpoB40 cells, proliferative activity and clonogenicity were reduced in response to IR, whereas patupilone, as expected, inhibited proliferation of the mutant cell line with reduced potency. Combined treatment with patupilone and IR induced a cytotoxic effect in vitro in an additive way in A549 cells but not in the tubulin-mutated, patupilone-resistant A549.EpoB40 cells. A supra-additive tumor growth delay was induced by combined treatment in xenografts derived from A549 cells but not in xenografts derived from A549.EpoB40 cells. Histologic analysis revealed a significant decrease in tumor cell proliferation (Ki-67) and microvessel density and a treatment-dependent change of tumor hypoxia in A549 but not A549.EpoB40 xenografts. CONCLUSIONS: Using a genetically defined patupilone-sensitive and patupilone-resistant tumor model, we here showed that the major cytotoxic effect of the combined treatment modality of IR and patupilone is directed against the tumor cell compartment. The induced antiangiogenic effect derives indirectly from the tumor cell.

Combined treatment strategies for microtubule stabilizing agent-resistant tumors.

BACKGROUND: Resistance to microtubule-stabilizing agents is a major hurdle for successful cancer therapy. We investigated combined treatment of microtubule-stabilizing agents (MSAs) with inhibitors of angiogenesis to overcome MSA resistance. METHODS: Treatment regimens of clinically relevant MSAs (patupilone and paclitaxel) and antiangiogenic agents (everolimus and bevacizumab) were investigated in genetically defined MSA-resistant lung (A549EpoB40) and colon adenocarcinoma (SW480) tumor xenografts in nude mice (CD1-Foxn1, ICRnu; 5-14 per group). Tumor growth delays were calculated by Kaplan-Meier analysis with Holm-Sidak tests. All statistical tests were two-sided. RESULTS: Inhibition of mTOR-kinase by everolimus only minimally reduced the proliferative activity of ß tubulin-mutated lung adenocarcinoma cells alone and in combination with the MSA patupilone, but everolimus inhibited expression and secretion of vascular endothelial growth factor (VEGF) from these cells. mTOR-kinase inhibition strongly sensitized tumor xenografts derived from these otherwise MSA-resistant tumor cells to patupilone. Tumors treated with the combined modality of everolimus and patupilone had statistically significantly reduced tumor volume and stronger tumor growth delay (16.2 ± 1.01 days) than control- (7.7 ± 0.3 days, P = .004), patupilone- (10 ± 0.97 days, P = .009), and everolimus-treated (10.6 ± 1.4 days, P = .014) tumors. A combined treatment modality with bevacizumab also resensitized this MSA-refractory tumor model to patupilone. Treatment combination also strongly reduced microvessel density, corroborating the relevance of VEGF targeting for the known antivasculature-directed potency of MSA alone in MSA-sensitive tumor models. Resensitization to MSAs was also probed in P glycoprotein-overexpressing SW480-derived tumor xenografts. Different bevacizumab regimens also sensitized this otherwise-resistant tumor model to clinically relevant MSA paclitaxel. CONCLUSIONS: A treatment combination of MSAs with antiangiogenic agents is potent to overcome tumor cell-linked MSA resistance and should be considered as strategy for MSA-refractory tumor entities.

Microtubule stabilising agents and ionising radiation: multiple exploitable mechanisms for combined treatment.

Combined radiochemotherapy treatment modalities are in use for many indications and therefore of high interest. Even though a combined modality in clinical use is often driven by pragmatic aspects, mechanistic preclinical-based concepts of interaction are of importance in order to translate and implement an optimal combination and scheduling of two modalities into the clinics. The use of microtubule stabilising agents is a promising strategy for anti-cancer therapy as a part of combined treatment modality with ionising radiation. Traditionally, microtubule targeting agents are classified as cytotoxic chemotherapeutics and are mostly used in a maximally tolerated dose regimen. Apart from direct cytotoxicity and similar to mechanisms of molecular targeting agents, microtubule stabilising agents interfere with multiple cellular processes, which can be exploited as part of combined treatment modalities. Recent preclinical investigations on the combination of ionising radiation and microtubule stabilising agents reveal new mechanistic interactions on the cellular and tumour level and elucidate the supra-additive tumour response observed particularly in vivo. The major focus on the mechanism of interaction was primarily based on radiosensitisation due to cell cycle arrest in the most radiosensitive G2/M-phase of the cell cycle. However, other mechanisms of interaction such as reoxygenation and direct as well as indirect endothelial damage have also been identified. In this review we summarise and allocate additive and synergistic effects induced by the combined treatment of clinically relevant microtubule stabilising agents and ionising radiation along a described radiobiological framework encompassing distinct mechanisms relevant for exploiting the combination of drugs and ionising radiation.

Dynamics of tumor hypoxia in response to patupilone and ionizing radiation.

Tumor hypoxia is one of the most important parameters that determines treatment sensitivity and is mainly due to insufficient tumor angiogenesis. However, the local oxygen concentration in a tumor can also be shifted in response to different treatment modalities such as cytotoxic agents or ionizing radiation. Thus, combined treatment modalities including microtubule stabilizing agents could create an additional challenge for an effective treatment response due to treatment-induced shifts in tumor oxygenation. Tumor hypoxia was probed over a prolonged observation period in response to treatment with different cytotoxic agents, using a non-invasive bioluminescent ODD-Luc reporter system, in which part of the oxygen-dependent degradation (ODD) domain of HIF-1α is fused to luciferase. As demonstrated in vitro, this system not only detects hypoxia at an ambient oxygen concentration of 1% O(2), but also discriminates low oxygen concentrations in the range from 0.2 to 1% O(2). Treatment of A549 lung adenocarcinoma-derived tumor xenografts with the microtubule stabilizing agent patupilone resulted in a prolonged increase in tumor hypoxia, which could be used as marker for its antitumoral treatment response, while irradiation did not induce detectable changes in tumor hypoxia. Furthermore, despite patupilone-induced hypoxia, the potency of ionizing radiation (IR) was not reduced as part of a concomitant or adjuvant combined treatment modality.

Regulation of VEGF-expression by patupilone and ionizing radiation in lung adenocarcinoma cells.

The use of microtubule stabilizing agents (MSAs) is a promising strategy for anti-cancer therapy alone and as part of combined treatment modalities with ionizing radiation. However MSA-provoked molecular and cellular processes including the regulation of intercellular, paracrine signaling pathways are far from clear. Here we investigated the interference of the novel, clinically relevant MSA patupilone (epothilone B) with the tumor-cell derived vascular endothelial growth factor (VEGF), which is most relevant for tumor angiogenesis. Low-dose, sub-nanomolar concentrations of patupilone specifically reduced hypoxia-driven stabilization of the transcription factor HIF-1α in the patupilone-sensitive lung adenocarcinoma cell line A549, but not in the mutant derivative cell line A549.EpoB40. Patupilone further reduced hypoxia-induced VEGF expression and secretion but only in the A549 wildtype cell line. In the wildtype cell line, ionizing radiation alone induced hypoxia-dependent VEGF-expression but a strong dominant counteracting effect of patupilone was always observed when ionizing radiation was combined with patupilone, on the level of HIF-1α protein stability, VEGF-expression and VEGF-secretion. These results demonstrate that patupilone and ionizing radiation dysregulate hypoxia-induced stress responses, which might contribute to the potency of this promising, combined treatment modality.

The microtubule stabilizer patupilone (epothilone B) is a potent radiosensitizer in medulloblastoma cells.

Concurrent radiochemotherapy for medulloblastoma includes the microtubule disrupting agent vincristine; however, vincristine alone or as part of a combined treatment regimen is highly toxic. A major goal is therefore to replace vincristine with novel potent chemotherapeutic agents-in particular, with microtubule stabilizing and destabilizing compounds-with a larger therapeutic window. Here, we investigated the antiproliferative, cytotoxic and radiosensitizing effect of patupilone (epothilone B [EPO906]), a novel, non-taxane-related and nonneurotoxic microtubule-stabilizing agent in human medulloblastoma cell lines. The antiproliferative and cytotoxic effects of patupilone alone and in combination with ionizing radiation was determined in the 3 representative human medulloblastoma cell lines D341Med, D425Med, and DAOY. Patupilone alone effectively reduced the proliferative activity and clonogenicity of all medulloblastoma cell lines tested at picomolar concentrations (50-200 pM) and resulted in an at least additive anticlonogenic effect in combination with clinically relevant doses of ionizing radiation (2 or 5 Gy). Cell-cycle analysis revealed a sequential G2-M arrest and sub-G1 accumulation in a dose- and treatment-dependent manner after exposure to patupilone. In tumor xenografts derived from D425Med cells, a minimal treatment regimen with patupilone and fractionated irradiation (1 × 2 mg/kg plus 3 × 3 Gy) resulted in an extended tumor growth delay for the 2 single treatment modalities alone and a supra-additive treatment response for the combined treatment modality, with complete tumor regressions. These results demonstrate the potent efficacy of patupilone against medulloblastoma cell lines and indicate that patupilone represents a promising candidate to replace vincristine as part of a combined treatment strategy with ionizing radiation.