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Preventing invasive breast neoplasia with chloroquine

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The PINC trial (NCT01023477) examined the dosage efficacy of oral chloroquine (CQ), an autophagy inhibitor, as a neoadjuvant therapy to reduce the volume, cause regression and decrease the recurrence of breast ductal carcinoma in situ (DCIS), for any grade or ER/PR/Her2 status. Study Objectives: Establish the safety of preventive doses of chloroquine in patients receiving external beam radiation. Elucidate functional molecular and cellular impacts of in vivo autophagy pathway treatment for DCIS. Study the impact of autophagy inhibitors on the MRI characteristics of DCIS lesions. Study the molecular cytogenetic profile of DCIS lesions before and after therapy. This trial implemented a general strategy to accelerate the pace of community-based translational research. Technology for providing immediate feedback on the therapeutic efficacy at the molecular level can be broadly extended to other trials. Methodology: 12 patients diagnosed with DCIS (any grade or ER/PR/Her2 status) were enrolled and randomly assigned to receive CQ at 250mg/week (n=5) or 500mg/week (n=7) for 4 weeks, followed by standard of care surgical therapy. MRI was performed before/after CQ treatment. DCIS spheroid forming cells were isolated and propagated from fresh human DCIS lesions. DCIS cells were characterized by organ culture, xenograft transplantation, molecular cytogenetics, and 59 cell signaling kinases were quantified by Reverse Phase Protein Microarrays.

Results: 12 patients completed 4 weeks of CQ treatment prior to surgical excision of their DCIS lesion, with 1 yr follow-up information. CQ treatment reduced PCNA proliferation index in DCIS lesions compared to untreated controls (p=0.001) and inhibited autophagic flux (LC3B positive puncta by IHC). CQ reduced the number of mammospheres in organoid culture without altering copy number variation. Xenograft transplants in NOD/SCID mouse mammary fat pads failed to generate tumors (n=4). 7/12 patients exhibited a reduction in lesion diameter by MRI, 3/12 patients exhibited no measurable change, and 2/12 had a slight increase. Calcium export channel protein (PMCA2) co-localized with 3+ HER2 positive DCIS lesions. Tumor infiltrating macrophages migrated into DCIS ducts following CQ therapy compared to controls (p=0.006). Conclusion: Oral chloroquine, as anti-autophagy therapy, generates a measurable reduction in proliferation of DCIS lesions and enhances immune cell migration into the duct.

Attacking breast cancer at the pre-invasion stage by targeting autophagy

Pre-invasive breast carcinoma cells that proliferate and accumulate within the non-vascular, closed intraductal niche are under severe hypoxic and metabolic stress. Understanding the survival mechanisms used by these cells has revealed therapeutic strategies for killing pre-invasive neoplasms. We have found that autophagy (“self eating”) is a major survival strategy used by pre-invasive carcinoma and breast cancer stem-like cells. Based on this finding, we have opened a clinical trial that is exploring neoadjuvant oral chloroquine anti-autophagy therapy for DCIS. We envision that antiautophagy therapy can be administered in combination with other treatments such as those which elevate intracellular calcium, to create a state of intolerable stress for pre-invasive neoplastic cells, and thereby stop breast cancer before it starts.

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