Low-dose taxotere enhances the ability of sorafenib to induce apoptosis in gastric cancer models

PLGA Nanoparticles Loaded with Sorafenib Combined with Thermosensitive Hydrogel System and Microwave Hyperthermia for Multiple Sensitized Radiotherapy

Hypoxia is typically the leading cause of radiotherapy (RT) resistance in solid tumors, and glutathione (GSH) overexpression in tumor cells is a potent antioxidant mechanism that protects tumor cells from radiation damage. Herein, we developed a sorafenib (SFN) loaded-PLGA hydrogel system (SPH) in combination with microwave (MW) hyperthermia for RT sensitization. SPH with stable properties was produced by combining SFN and PLGA in a specific ratio and encapsulating the mixture in agarose hydrogel. Intratumoral injection of SPH to mice combined with MW hyperthermia can not only directly cause thermal damage to tumor cells, but also increase blood oxygen delivery to the tumor site, thus overcoming the problem of intratumoral hypoxia and achieving "first layer" RT sensitization. Moreover, high temperatures can cause the hydrogel to disintegrate and release SFN. Not only can SFN inhibit tumor growth, but it can also achieve the "second layer" of RT sensitization by inhibiting glutathione (GSH) synthesis in cells and increasing reactive oxygen species (ROS) production. Experiments, both in vitro and in vivo, have indicated that SPH and MW hyperthermia can achieve a double RT sensitization effect and a significant tumor inhibition effect. In conclusion, combining our SPH nanosystem and thermoradiotherapy is a promising anti-tumor treatment.

Pterostilbene enhances sorafenib's anticancer effects on gastric adenocarcinoma

Sorafenib has been approved for the treatment of certain cancers in clinic. However, the effects of sorafenib on gastric adenocarcinoma (GAC) were still limited. This study aimed to evaluate both in vitro and in vivo efficacy of sorafenib in combination with pterostilbene (PTE) on the treatment of GAC. Here, the morphological changes and cell viability were recorded in both N87 and MKN45 cells. The cell cycle profile and apoptosis were assessed by flow cytometry. Subcutaneous tumour xenografts were constructed in nude mice, and IHC staining of the dissected tumour tissues was conducted. Our results showed that PTE enhanced sorafenib's inhibitory effects on cell viability. The obvious down‐regulation of cyclin D1, Cdk‐2, Cdk‐4, Cdk‐6 and p62 and the up‐regulation of LC3II, caspase‐9, caspase‐3 and PARP cleavages were observed for the combination treatment with PTE and sorafenib than monotherapy. The combination treatment resulted in a higher level of cell cycle arrest at G1 phase and apoptosis than either drug. Besides, drug combination significantly enhanced the inhibition of tumour growth than sorafenib or PET alone in nude mice. The percentage of Ki‐67‐ and PCNA‐positive cells was distinctly reduced, and the apoptotic cells was obviously increased when compared with single drug therapy. Altogether, PET obviously enhanced sorafenib's antitumour effects against GAC through inhibiting cell proliferation, inducing autophagy and promoting apoptosis. The combination therapy with PET and sorafenib may serve as a novel therapeutic strategy for treating GAC and deserve further clinical trials.

Sorafenib inhibits 5-fluorouracil-resistant gastric cancer cell growth

BACKGROUND

Sorafenib is a multi-kinase inhibitor used in the treatment of various cancers. This study investigated the inhibitory effect of sorafenib on xenograft models of gastric cancer cells and 5-fluorouracil (5-FU)-resistant cells.

METHODS

The half-maximal inhibitory concentration (IC₅₀) of sorafenib in NCI-N87 cells was determined. Xenograft models were established using BALB/c nude mice and were divided into four groups treated with vehicle, sorafenib (20 mg kg^-1 day^-1), 5-FU (50 mg kg^-1 week^-1), or a combination of sorafenib (20 mg kg^-1 day^-1) plus 5-FU (50 mg kg^-1 week^-1). 5-FU-resistant NCI-N87 cells were established by repeated exposure to 5-FU.

RESULTS

Sorafenib inhibited NCI-N87 cell growth in a concentration-dependent manner with a mean IC₅₀ of 16.345 ± 5.391 μM. Phosphorylation levels of mitogen-activated protein kinase kinase and extracellular signal-regulated kinase in these cells decreased in a dose-dependent manner after exposure to sorafenib. Sorafenib induced the activation of caspase-3, and its combination with 5-FU more effectively inhibited the growth of xenograft tumors than either sorafenib or 5-FU alone (p < 0.05). Sorafenib markedly inhibited 5-FU-resistant NCI-N87 cell growth as well as sphere formation in both parental and 5-FU-resistant NCI-N87 cells.

CONCLUSIONS

The sorafenib and 5-FU combination exhibited enhanced antitumor effects in a gastric cancer xenograft model and inhibited 5-FU-resistant cell proliferation and sphere formation. These findings suggest that sorafenib is useful in overcoming gastric cancer resistance to conventional chemotherapy.

Phase I study of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer

PURPOSE

We performed a dose-escalation study to investigate the safety of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

Six patients were included per dose level. Following docetaxel infusion on day 1 (75 mg/m(2)/q3 weeks), sorafenib was administered at 200 mg BID on days 2-19 (dose level 1), at 200 mg BID on days 1-21 (dose level 2), at 400 mg BID on days 2-19 (dose level 3), at 400 mg BID on days 1-21 (dose level 4). Maximal tolerated dose (MTD) was exceeded if ≥2 patients experienced dose-limiting toxicities (DLT) during cycle 1. The recommended phase 2 dose for sorafenib was defined as one dose level below MTD. If MTD was not reached, the highest feasible dose would be selected to treat an expanded cohort to confirm safety.

RESULTS

Two DLTs were observed during sorafenib dose-escalation consisting of grade 4 febrile neutropenia (dose level 2) and grade 3 hand-foot syndrome (HFS) (dose level 3). Our pharmacokinetic results showed an increased exposure to docetaxel across all dose levels during sorafenib comedication. The main grade ≥3 toxicities were neutropenia (35 %), HFS (27 %), and febrile neutropenia (19 %). The prostate-specific antigen (PSA) response rate was 74 %. Median overall survival was 25.2 months.

CONCLUSION

Three-weekly docetaxel and prednisone could be combined with sorafenib at 400 mg BID on days 1-21 without reaching MTD. However, we observed a pharmacokinetic interaction between sorafenib and docetaxel, associated with significant toxicities, raising concerns about the safety of this combination in mCRPC.

Targeted therapies for gastric cancer: current status

Gastric cancer represents one of the most common cancers internationally. Unfortunately the majority of patients still present at an advanced stage, and despite advances in diagnostic and treatment strategies, outcomes still remain poor with high mortality rates despite a decline in incidence. Whilst the utility of classical chemotherapy agents has been explored thoroughly (and continues to be investigated, alone or in various combinations), advances have been slow and the efficacy of these agents has reached a plateau. As such, the focus of recent study has shifted toward developing a greater understanding of the molecular biology of carcinogenesis and the cancer cell phenotype, and, in turn, the development of rationally designed drugs that target molecular aberrancies in signal transduction pathways specific to gastric cancer. These targets include circulating growth and angiogenic factors, cell surface receptors, and other molecules that comprise downstream intracellular signalling pathways, including receptor tyrosine kinases. Therapeutic advances in this area significantly lag behind other solid organ malignancies such as breast and colorectal cancer. This article reviews the role of targeted therapies in gastric cancer, including rationale and mechanism of action, current and emerging data, as single-agent therapy or in combination regimens. A recently published randomized phaseIII trial supporting the use of trastuzumab, an anti-human epidermal growth factor receptor 2 (HER2)/neu monoclonal antibody, in a selected population of patients is discussed. Therapies that have been evaluated in phase II trials are also reviewed, as well as promising new therapies currently being investigated in preclinical or phase I studies. There is optimism that targeted therapies, whether as single-agent therapy or in combination with traditional therapies, including chemotherapy, radiotherapy and surgery, may yet have an impact on improvement of the overall prognosis of gastric cancer.