Copper deprivation enhances the chemosensitivity of pancreatic cancer to rapamycin by mTORC1/2 inhibition

Cuproplasia, or copper-dependent cell proliferation, has been observed in varieties of solid tumors along with aberrant copper homeostasis. Several studies reported good response of patients to copper chelator assisted neoadjuvant chemotherapy, however, the internal target molecules are still undetermined. Unravel copper-associated tumor signaling would be valuable to forge new links to translate biology of copper into clinical cancer therapies. We evaluated the significance of high-affinity copper transporter-1 (CTR1) by bioinformatic analysis, and in 19 pairs of clinical specimens. Then, with the help of gene interference and chelating agent, enriched signaling pathways were identified by KEGG analysis and immunoblotting. Accompanying biological capability of pancreatic carcinoma-associated proliferation, cell cycle, apoptosis, and angiogenesis were investigated. Furthermore, a combination of mTOR inhibitor and CTR1 suppressor has been assessed in xenografted tumor mouse models. Hyperactive CTR1 was investigated in pancreatic cancer tissues and proven to as the key point of cancer copper homeostasis. Intracellular copper deprivation induced by CTR1 gene knock-down or systematic copper chelation by tetrathiomolybdate suppressed proliferation and angiogenesis of pancreatic cancer cell. PI3K/AKT/mTOR signaling pathway was suppressed by inhibiting the activation of p70(S6)K and p-AKT, and finally inhibited mTORC1 and mTORC2 after copper deprivation. Additionally, CTR1 gene silencing successfully improved the anti-cancer effect of mTOR inhibitor rapamycin. Our study reveals that CTR1 contributes to pancreatic tumorigenesis and progression, by up-regulating the phosphorylation of AKT/mTOR signaling molecules. Recovering copper balance by copper deprivation addresses as promising strategy for improved cancer chemotherapy.

First-In-Human Phase I Study Of A Dual mTOR Kinase And DNA-PK Inhibitor (CC-115) In Advanced Malignancy

Purpose

This first-in-human Phase I study investigated the safety, pharmacokinetics (PK), pharmacodynamic profile, and preliminary efficacy of CC-115, a dual inhibitor of mammalian target of rapamycin (mTOR) kinase and DNA-dependent protein kinase.

Patients and Methods

Patients with advanced solid or hematologic malignancies were enrolled in dose-finding and cohort expansion phases. In dose-finding, once-daily or twice-daily (BID) ascending oral doses of CC-115 (range: 0.5-40 mg/day) in 28-day continuous cycles identified the maximum-tolerated dose for cohort expansion in 5 specified tumor types. Twelve additional patients with mixed solid tumors participated in a bioavailability substudy.

Results

Forty-four patients were enrolled in the dose-finding cohort. Dose-limiting toxicity included thrombocytopenia, stomatitis, hyperglycemia, asthenia/fatigue, and increased transaminases. CC-115 10 mg BID was selected for cohort expansion (n=74) in which fatigue, nausea, and decreased appetite were the most frequent toxicities. Dose-proportional PK was found. CC-115 distributed to glioblastoma tissue (mean tumor/plasma concentration ratio: 0.713). Total exposure of CC-115 was similar under fasting and fed conditions. A patient with endometrial carcinoma remained in complete remission >4 years. Partial response (PR; n=2) and stable disease (SD; n=4) were reported in the bioavailability substudy; SD was reached in 53%, 22%, 21%, and 64% of patients with head and neck squamous cell carcinoma, Ewing sarcoma, glioblastoma multiforme, and castration-resistant prostate cancer, respectively. Chronic lymphocytic leukemia/small lymphocytic lymphoma showed 38% PR and 25% SD.

Conclusion

CC-115 was well-tolerated, with toxicities consistent with mTOR inhibitors. Together with biomarker inhibition and preliminary efficacy, oral CC-115 10 mg BID is a promising novel anticancer treatment.

Clinical trial registration

NCT01353625.

A phase I dose-escalation study to assess safety, tolerability, pharmacokinetics, and preliminary efficacy of the dual mTORC1/mTORC2 kinase inhibitor CC-223 in patients with advanced solid tumors or multiple myeloma

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is essential for tumor development, yet mTOR inhibitors have yielded modest results. This phase 1 study investigated the mTORC1/mTORC2 inhibitor CC-223 in patients with advanced cancer.

METHODS

Patients with advanced solid tumors or multiple myeloma received an initial dose of 7.5-60 mg of CC-223, followed by oral daily dosing in 28-day cycles until disease progression. The primary objective was to determine the safety, tolerability, nontolerated dosage, maximum tolerated dosage (MTD), and preliminary pharmacokinetic profile. Secondary objectives were to evaluate pharmacodynamic effects and to describe preliminary efficacy.

RESULTS

Twenty-eight patients were enrolled and received ≥1 dose of CC-223. The most common treatment-related grade 3 adverse events were hyperglycemia, fatigue, and rash. Four patients had dose-limiting toxicities, including hyperglycemia, rash, fatigue, and mucositis. Therefore, 45 mg/d was determined to be the MTD. The pharmacokinetics of CC-223 demonstrated a mean terminal half-life ranging from 4.86 to 5.64 hours and maximum observed plasma concentration ranging from 269 to 480 ng/mL in patients who received CC-223 ≥45 mg/d. Phosphorylation of mTORC1/mTORC2 pathway biomarkers in blood cells was inhibited by CC-223 ≥30 mg/d with an exposure-response relationship. Best responses included 1 partial response (breast cancer; response duration 220 days; 30-mg/d cohort), stable disease (8 patients across ≥15 mg/d cohorts; response duration range, 36-168 days), and progressive disease (12 patients). The disease control rate was 32%.

CONCLUSIONS

CC-223 was tolerable, with manageable toxicities. Preliminary antitumor activity, including tumor regression, and evidence of mTORC1/mTORC2 pathway inhibition were observed.