Results and Molecular Correlates from a Pilot Study of Neoadjuvant Induction FOLFIRINOX Followed by Chemoradiation and Surgery for Gastroesophageal Adenocarcinomas.

PURPOSE: We performed a NCI-sponsored, prospective study of neoadjuvant FOLFIRINOX followed by chemoradiation with carboplatin/paclitaxel followed by surgery in patients with locally advanced gastric or gastroesophageal cancer. PATIENTS AND METHODS: The primary objective was to determine completion rate of neoadjuvant FOLFIRINOX × 8 followed by chemoradiation. Secondary endpoints were toxicity and pathologic complete response (pCR) rate. Exploratory analysis was performed of circulating tumor DNA (ctDNA) to treatment response. RESULTS: From October 2017 to June 2018, 25 patients were enrolled. All patients started FOLFIRINOX, 92% completed all eight planned cycles, and 88% completed chemoradiation. Twenty (80%) patients underwent surgical resection, and 7 had a pCR (35% in resected cohort, 28% intention to treat). Tumor-specific mutations were identified in 21 (84%) patients, of whom 4 and 17 patients had undetectable and detectable ctDNA at baseline, respectively. Presence of detectable post-chemoradiation ctDNA (P = 0.004) and/or postoperative ctDNA (P = 0.045) were associated with disease recurrence. CONCLUSIONS: Here we show neoadjuvant FOLFIRINOX followed by chemoradiation for locally advanced gastroesophageal cancer is feasible and yields a high rate of pCR. ctDNA appears to be a promising predictor of postoperative recurrence.See related commentary by Catenacci, p. 6281.

From the ground up: recognising risk of frailty syndromes and functional decline through foot examination.

Foot pathologies in older adults are associated with falls and complications such as amputations and ulcers. We report a case of an older man who presented to the geriatric medicine outpatient clinic. History taking revealed a fall, recent episode of delirium and decline in functional status with the patient reporting he was no longer able to cut his own toenails. Medical history included hypothyroidism, depression and hearing impairment. Physical examination detected very long, thickened toenails with bilateral bony deformities of the foot. Additionally, he had borderline slow gait speed and had difficulty completing a chair stand. Inability to maintain foot care suggested an early insight into a deterioration of overall function and emergence of frailty. An interprofessional team approach to the patient's care included a medication review, referrals to podiatry, orthotics, physiotherapy and occupational therapy. His toenails were debrided and orthopaedic shoes were prescribed with no further falls.

Rapamycin-upregulated miR-29b promotes mTORC1-hyperactive cell growth in TSC2-deficient cells by downregulating tumor suppressor retinoic acid receptor ß (RARß).

miR-29b has been identified as a rapamycin-induced microRNA (miRNA) in Tsc2-deficient, mTORC1-hyperactive cells. The biological significance of this induction of miR-29b is unknown. We have found that miR-29b acts as an oncogenic miRNA in Tsc2-deficient cells: inhibition of miR-29b suppressed cell proliferation, anchorage-independent cell growth, cell migration, invasion, and the growth of Tsc2-deficient tumors in vivo. Importantly, the combination of miR-29b inhibition with rapamycin treatment further inhibited these tumor-associated cellular processes. To gain insight into the molecular mechanisms by which miR-29b promotes tumorigenesis, we used RNA sequencing to identify the tumor suppressor retinoid receptor beta (RARß) as a target gene of miR-29b. We found that miR-29b directly targeted the 3'UTR of RARß. Forced expression of RARß reversed the effects of miR-29b overexpression in proliferation, migration, and invasion, indicating that it is a critical target. miR-29b expression correlated with low RARß expression in renal clear cell carcinomas and bladder urothelial carcinomas, tumors associated with TSC gene mutations. We further identified growth family member 4 (ING4) as a novel interacting partner of RARß. Overexpression of ING4 inhibited the migration and invasion of Tsc2-deficient cells while silencing of ING4 reversed the RARß-mediated suppression of cell migration and invasion. Taken together, our findings reveal a novel miR-29b/RARß/ING4 pathway that regulates tumorigenic properties of Tsc2-deficient cells, and that may serve as a potential therapeutic target for TSC, lymphangioleiomyomatosis (LAM), and other mTORC1-hyperactive tumors.

Pencil Beam Scanning Proton Beam Chemoradiation Therapy With 5-Fluorouracil and Mitomycin-C for Definitive Treatment of Carcinoma of the Anal Canal: A Multi-institutional Pilot Feasibility Study.

PURPOSE: Definitive chemoradiation with concurrent 5-fluorouracil (5-FU)/mitomycin C (MMC) is an effective treatment for localized anal cancer, but it is associated with significant acute long-term treatment-related toxicity. Pencil beam scanning proton beam (PBS-PT) radiation therapy may potentially reduce this toxicity. This is a multi-institutional pilot study evaluating the feasibility of definitive concurrent chemoradiation with PBS-PT in combination with 5-FU and MMC for carcinoma of the anal canal. METHODS AND MATERIALS: Patients were enrolled on a National Cancer Institute-sponsored, prospective, multi-institutional, single-arm pilot study (NCT01858025). Key eligibility criteria included Eastern Cooperative Oncology Group 0 to 2, age ≥18 years, histologically confirmed invasive squamous cell carcinoma of the anal canal, and clinically staged T1-4, N0-3 disease. Patients were treated with PBS-PT per Radiation Therapy Oncology Group 0529 dose schema and concurrent 5-FU/MMC on day 1 and 29. The primary objective of this study was to determine feasibility of PBS-PT with concurrent 5-FU/MMC, defined as grade 3+ dermatologic toxicity less than 48% (reported grade 3+ dermatologic toxicity from Radiation Therapy Oncology Group 98-11). Secondary objectives were to determine the rates of overall grade 3+ toxicities, clinical complete response rate, and disease outcomes. RESULTS: Between February 2014 and April 2017, we enrolled 25 patients into our study, all of whom were analyzed. Twenty-three patients (92%) completed treatment per protocol, and 2 patients died on treatment. Median time to completion of treatment was 42 days (range, 38-49). The grade 3+ radiation dermatitis rate was 24%. Median follow-up is 27 months (range, 21-50) among the 21 patients still alive. The overall rate of clinical complete response was 88%. The 2-year local failure, colostomy-free survival, progression-free survival, and overall survival are 12%, 72%, 80%, and 84%, respectively. CONCLUSIONS: In our prospective, multi-institutional pilot study of PBS-PT with concurrent 5-FU/MMC, PBS-PT was found to be feasible. A phase 2 study of proton beam radiation therapy is currently underway.

Total Neoadjuvant Therapy With FOLFIRINOX in Combination With Losartan Followed by Chemoradiotherapy for Locally Advanced Pancreatic Cancer: A Phase 2 Clinical Trial.

IMPORTANCE: Patients with locally advanced pancreatic cancer have historically poor outcomes. Evaluation of a total neoadjuvant approach is warranted. OBJECTIVE: To evaluate the margin-negative (R0) resection rate of neoadjuvant FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and irinotecan) and losartan followed by chemoradiotherapy for locally advanced pancreatic cancer. DESIGN, SETTING, AND PARTICIPANTS: A single-arm phase 2 clinical trial was conducted at a large academic hospital from August 22, 2013, to May 22, 2018, among 49 patients with previously untreated locally advanced unresectable pancreatic cancer as determined by multidisciplinary review. Patients had Eastern Cooperative Oncology Group performance status 0 or 1 and adequate hematologic, renal, and hepatic function. Median follow-up for the analysis was 17.1 months (range, 5.0-53.7) among 27 patients still alive at study completion. INTERVENTIONS: Patients received FOLFIRINOX and losartan for 8 cycles. Patients with radiographically resectable tumor after chemotherapy received short-course chemoradiotherapy (5 GyE × 5 with protons) with capecitabine. Patients with persistent vascular involvement received long-course chemoradiotherapy (50.4 Gy with a vascular boost to 58.8 Gy) with fluorouracil or capecitabine. MAIN OUTCOMES AND MEASURES: R0 resection rate. RESULTS: Of the 49 patients (26 women and 23 men; median age 63 years [range, 42-78 years]), 39 completed 8 cycles of FOLFIRINOX and losartan; 10 patients had fewer than 8 cycles due to progression (5 patients), losartan intolerance (3 patients), and toxicity (2 patients). Seven patients (16%) had short-course chemoradiotherapy while 38 (84%) had long-course chemoradiotherapy. Forty-two (86%) patients underwent attempted surgery, with R0 resection achieved in 34 of 49 patients (69%; 95% CI, 55%-82%). Overall median progression-free survival was 17.5 months (95% CI: 13.9-22.7) and median overall survival was 31.4 months (95% CI, 18.1-38.5). Among patients who underwent resection, median progression-free survival was 21.3 months (95% CI, 16.6-28.2), and median overall survival was 33.0 months (95% CI, 31.4 to not reached). CONCLUSIONS AND RELEVANCE: Total neoadjuvant therapy with FOLFIRINOX, losartan, and chemoradiotherapy provides downstaging of locally advanced pancreatic ductal adenocarcinoma and is associated with an R0 resection rate of 61%. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01821729.

Rapamycin-induced miR-21 promotes mitochondrial homeostasis and adaptation in mTORC1 activated cells.

mTORC1 hyperactivation drives the multi-organ hamartomatous disease tuberous sclerosis complex (TSC). Rapamycin inhibits mTORC1, inducing partial tumor responses; however, the tumors regrow following treatment cessation. We discovered that the oncogenic miRNA, miR-21, is increased in Tsc2-deficient cells and, surprisingly, further increased by rapamycin. To determine the impact of miR-21 in TSC, we inhibited miR-21 in vitro. miR-21 inhibition significantly repressed the tumorigenic potential of Tsc2-deficient cells and increased apoptosis sensitivity. Tsc2-deficient cells' clonogenic and anchorage independent growth were reduced by ∼50% (p<0.01) and ∼75% (p<0.0001), respectively, and combined rapamycin treatment decreased soft agar growth by ∼90% (p<0.0001). miR-21 inhibition also increased sensitivity to apoptosis. Through a network biology-driven integration of RNAseq data, we discovered that miR-21 promotes mitochondrial adaptation and homeostasis in Tsc2-deficient cells. miR-21 inhibition reduced mitochondrial polarization and function in Tsc2-deficient cells, with and without co-treatment with rapamycin. Importantly, miR-21 inhibition limited Tsc2-deficient tumor growth in vivo, reducing tumor size by approximately 3-fold (p<0.0001). When combined with rapamcyin, miR-21 inhibition showed even more striking efficacy, both during treatment and after treatment cessation, with a 4-fold increase in median survival following rapamycin cessation (p=0.0008). We conclude that miR-21 promotes mTORC1-driven tumorigenesis via a mechanism that involves the mitochondria, and that miR-21 is a potential therapeutic target for TSC-associated hamartomas and other mTORC1-driven tumors, with the potential for synergistic efficacy when combined with rapalogs.

mTORC1 Couples Nucleotide Synthesis to Nucleotide Demand Resulting in a Targetable Metabolic Vulnerability.

The mechanistic target of rapamycin complex 1 (mTORC1) supports proliferation through parallel induction of key anabolic processes, including protein, lipid, and nucleotide synthesis. We hypothesized that these processes are coupled to maintain anabolic balance in cells with mTORC1 activation, a common event in human cancers. Loss of the tuberous sclerosis complex (TSC) tumor suppressors results in activation of mTORC1 and development of the tumor syndrome TSC. We find that pharmacological inhibitors of guanylate nucleotide synthesis have selective deleterious effects on TSC-deficient cells, including in mouse tumor models. This effect stems from replication stress and DNA damage caused by mTORC1-driven rRNA synthesis, which renders nucleotide pools limiting. These findings reveal a metabolic vulnerability downstream of mTORC1 triggered by anabolic imbalance.

p62/SQSTM1 Cooperates with Hyperactive mTORC1 to Regulate Glutathione Production, Maintain Mitochondrial Integrity, and Promote Tumorigenesis.

p62/sequestosome-1 (SQSTM1) is a multifunctional adaptor protein and autophagic substrate that accumulates in cells with hyperactive mTORC1, such as kidney cells with mutations in the tumor suppressor genes tuberous sclerosis complex (TSC)1 or TSC2. Here we report that p62 is a critical mediator of TSC2-driven tumorigenesis, as Tsc2+/- and Tsc2f/f Ksp-CreERT2+ mice crossed to p62-/- mice were protected from renal tumor development. Metabolic profiling revealed that depletion of p62 in Tsc2-null cells decreased intracellular glutamine, glutamate, and glutathione (GSH). p62 positively regulated the glutamine transporter Slc1a5 and increased glutamine uptake in Tsc2-null cells. We also observed p62-dependent changes in Gcl, Gsr, Nqo1, and Srxn1, which were decreased by p62 attenuation and implicated in GSH production and utilization. p62 attenuation altered mitochondrial morphology, reduced mitochondrial membrane polarization and maximal respiration, and increased mitochondrial reactive oxygen species and mitophagy marker PINK1. These mitochondrial phenotypes were rescued by addition of exogenous GSH and overexpression of Sod2, which suppressed indices of mitochondrial damage and promoted growth of Tsc2-null cells. Finally, p62 depletion sensitized Tsc2-null cells to both oxidative stress and direct inhibition of GSH biosynthesis by buthionine sulfoximine. Our findings show how p62 helps maintain intracellular pools of GSH needed to limit mitochondrial dysfunction in tumor cells with elevated mTORC1, highlighting p62 and redox homeostasis as nodal vulnerabilities for therapeutic targeting in these tumors. Cancer Res; 77(12); 3255-67. ©2017 AACR.