Nicholas W. Bateman

Jupiter microtubule‐associated homolog 1 (JPT1): A predictive and pharmacodynamic biomarker of metformin response in endometrial cancers

AbstractPreoperative use of metformin in obese women with endometrioid endometrial cancer (EEC) reduces tumor proliferation and inhibits the mammalian target of rapamycin pathway, though is only effective in select cases. This study sought to identify a predictive and/or pharmacodynamic proteomic signature of metformin response to tailor its pharmacologic use. Matched pre‐ and post‐metformin‐treated tumor tissues from a recently completed preoperative window trial of metformin in EEC patients (ClinicalTrials.gov: NCT01911247) were analyzed by mass spectrometry (MS)‐based proteomic and immunohistochemical analyses. Jupiter microtubule‐associated homolog 1 (JPT1) was significantly elevated in metformin responders (n = 13) vs nonresponders (n = 7), and found to decrease in abundance in metformin responders following treatment; observations that were verified by immunohistochemical staining for JPT1. Metformin response and loss of JPT1 were assessed in RL95‐2 and ACI‐181 endometrial cancer (EC) cell lines. We further identified that silencing of JPT1 abundance does not alter cellular response to metformin or basal cell proliferation, but that JPT1 abundance does decrease in response to metformin treatment in RL95‐2 and ACI‐181 EC cell lines. These data suggest that JPT1 represents a predictive and pharmacodynamic biomarker of metformin response that, if validated in larger patient populations, may enable preoperative EEC patient stratification to metformin treatment and the ability to monitor patient response.

Automated imaging and identification of proteoforms directly from ovarian cancer tissue

AbstractThe molecular identification of tissue proteoforms by top-down mass spectrometry (TDMS) is significantly limited by throughput and dynamic range. We introduce AutoPiMS, a single-ion MS based multiplexed workflow for top-down tandem MS (MS2) directly from tissue microenvironments in a semi-automated manner. AutoPiMS directly off human ovarian cancer sections allowed for MS2identification of 73 proteoforms up to 54 kDa at a rate of <1 min per proteoform. AutoPiMS is directly interfaced with multifaceted proteoform imaging MS data modalities for the identification of proteoform signatures in tumor and stromal regions in ovarian cancer biopsies. From a total of ~1000 proteoforms detected by region-of-interest label-free quantitation, we discover 303 differential proteoforms in stroma versus tumor from the same patient. 14 of the top proteoform signatures are corroborated by MSI at 20 micron resolution including the differential localization of methylated forms of CRIP1, indicating the importance of proteoform-enabled spatial biology in ovarian cancer.

Preoperative Window Study of Metformin for the Treatment of Endometrial Cancer

The overall goal of this proposal is to investigate the potential benefit of metformin as a novel therapy for the treatment of endometrial cancer. Investigators will evaluate the effect of short-term metformin treatment on the endometrium of obese women with endometrial cancer by comparing each patient's endometrial biopsy before treatment with metformin to their post-treatment hysterectomy specimen. Participants: Obese women who are to undergo surgical staging for endometrial cancer will also receive short-term treatment (1-4 weeks) with metformin that will continue until the day prior to surgical staging. The effect of metformin on proliferation, apoptosis and downstream signaling pathways will be compared between pre-treatment endometrial biopsies and post-treatment hysterectomy specimens. Tissue microarrays will be constructed and immunohistochemstry performed to evaluate proliferation, apoptosis and changes in critical signaling pathways mediated by metformin, and these findings will be correlated with our in vitro preclinical studies. Fresh tissue will also be obtained, and Western immunoblotting will be used to assess expression of the phosphorylated forms of the downstream targets of metformin. The hypothesis is that treatment with metformin will result in a decrease in proliferative markers and an increase in markers of apoptosis in the endometrial cancer tumors. AMPK phosphorylation and inhibition of critical downstream targets of the mTOR pathway will be seen in the post-treatment hysterectomy specimens. Metabolomic profiling will also be performed of tumors and associated biofluids (i.e. serum and urine) before and after treatment with metformin to identify potential biomarkers of response to this therapy.