Taiho Oncology Presents Data on LONSURF® (trifluridine and tipiracil) and Futibatinib (TAS-120) at ASCO 2020 Gastrointestinal Cancers Symposium (ASCO GI)

On January 25, 2020 Taiho Oncology, Inc. reported the presentation of a pooled analysis for hematologic adverse events of the global Phase III TAGS and RECOURSE trials evaluating LONSURF (trifluridine and tipiracil) in patients with metastatic colorectal cancer (mCRC) and metastatic gastric or gastroesophageal junction cancer (mGC/GEJC), respectively (Press release, Taiho, JAN 25, 2020, View Source [SID1234553541]). The company also presented updates on two trials in progress with futibatinib, the Phase III FOENIX-CCA3 study of futibatinib as first-line treatment for patients with advanced cholangiocarcinoma (CCA) harboring FGFR 2 gene rearrangements and a Phase II basket study of futibatinib in patients with advanced solid tumors harboring FGFR genomic aberrations.

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These data were highlighted at the ASCO (Free ASCO Whitepaper) 2020 Gastrointestinal Cancers Symposium (ASCO GI) in San Francisco on January 23-25, 2020.

LONSURF Pooled Safety Analysis
The pooled safety analysis of the TAGS and RECOURSE trials determined that hematologic adverse events with LONSURF in subgroups of patients with mild to moderate renal impairment and mild hepatic impairment were manageable and similar to those in the overall patient population.

"Beyond the therapeutic effects of treatment and its impact on disease progression and survival in people living with cancer, the safety and tolerability of our medicines are the highest priority to us," said Karin Blakolmer, MD, MBA, Senior Vice President and Head of Medical Affairs, Taiho Oncology, Inc. "For patients treated with LONSURF in the TAGS and RECOURSE trials, we are pleased to see that hematologic adverse events for certain subgroups were in line with what we saw in the overall patient population and, as important, were manageable. This is good news for people living with metastatic colorectal cancer and metastatic gastric cancer who are receiving treatment with LONSURF."

Futibatinib Trials in Progress
The first trial in progress is FOENIX-CCA3, a Phase III multicenter, open-label, randomized study that will be conducted in patients with metastatic or unresectable intrahepatic CCA harboring FGFR2 rearrangements. Approximately 216 patients will be randomized to receive first-line therapy with 20 mg futibatinib once daily or gemcitabine and cisplatin for up to 8 cycles. Patients are to be treated until the first occurrence of disease progression, death or other protocol specified discontinuation criteria. The primary endpoint is progression-free survival (PFS). Secondary endpoints include objective response rate (ORR) and disease control rate and safety.

The second trial in progress is a Phase II global, open-label study that will explore treatment with futibatinib in patients (n=~60) with metastatic or locally advanced solid tumors, except primary brain tumors or intrahepatic CCA, harboring FGFR1–4 rearrangements and with disease progression after standard treatment (Cohort A), and in patients (n=~35) with metastatic or locally advanced gastric tumors harboring FGFR2 amplifications and with two or more lines of prior therapy (Cohort B). Patients will receive 20 mg of futibatinib once daily in a continuous 28-day cycle until disease progression, unacceptable toxicity or other discontinuation criteria are met. The primary endpoint is independently assessed ORR. Secondary endpoints include ORR per investigator, disease control rate, duration of response, PFS, overall survival and safety.

About TAGS
The TAGS (TAS-102 Gastric Study) trial was a Taiho-sponsored, global, pivotal Phase III, multinational, randomized, double-blind study evaluating LONSURF (trifluridine and tipiracil, FTD/TPI), plus best supportive care (BSC) versus placebo plus BSC in patients with metastatic gastric cancer, including gastroesophageal junction cancer, refractory to standard treatments. The primary endpoint in the TAGS trial was overall survival (OS), and the main secondary endpoint measures included progression-free survival (PFS), safety and tolerability, as well as quality of life.

The TAGS trial enrolled 507 adult patients with metastatic gastric cancer who had previously received at least two prior regimens for advanced disease. The study was conducted in 17 countries and 110 sites around the world.

About RECOURSE
The RECOURSE trial was a global, randomized, double-blind, placebo-controlled Phase III comparison trial evaluating the efficacy and safety of orally administered LONSURF in patients with previously treated mCRC. The trial enrolled 800 patients in North America, Japan, Europe and Australia. Patients were randomized (2:1) to receive LONSURF (35 mg/m2) or placebo, plus BSC, twice daily. The study met its primary and secondary endpoints of OS and PFS versus placebo.

About Metastatic Colorectal Cancer
Colorectal cancer is the 4th most commonly diagnosed cancer in the United States (U.S.).1 In 2019, there were an estimated 145,600 new cases and 51,020 deaths in the U.S.1 Approximately 22 percent of U.S. patients with colorectal cancer are diagnosed at the distant or metastasized stage.1 Metastatic colorectal cancer (mCRC) is associated with poor prognosis with a five-year survival rate of approximately 14 percent.1

Over the last decade, clinical outcomes for patients with mCRC have improved considerably due to the advent of novel treatment agents, predictive biomarkers, and a more strategic approach to the delivery of systemic therapies. Currently, the median overall survival for patients with mCRC being treated both in Phase III trials and in large observational series or registries is 30 months – more than double that of 20 years ago.2,3,4

About Cholangiocarcinoma

Cholangiocarcinoma (CCA), also known as bile duct cancer, is not common. About 8,000 people in the U.S. are diagnosed with CCA each year.5 This includes both intrahepatic (inside the liver) and extrahepatic (outside the liver) cancers. CCA can occur at younger ages, but it is seen mainly in older people. The average age of people in the U.S. diagnosed with cancer of the intrahepatic bile ducts is 70, and for cancer of the extrahepatic bile ducts it is 72.5 The chances of survival for patients with CCA depend to a large extent on its location and how advanced it is when it is found.5

The main treatment for CCA is surgery. Radiation therapy and chemotherapy may be used if the cancer cannot be entirely removed with surgery and in cases where the edges of the tissues removed at the operation show cancer cells (also called a positive margin). Both stage III and stage IV cancers cannot be completely removed surgically. Currently, standard treatment options are limited to radiation, palliative therapy, liver transplantation, surgery, chemotherapy and interventional radiology.6

About Metastatic Gastric Cancer
Gastric cancer, also known as stomach cancer, is the 15th most commonly diagnosed cancer in the U.S.7 In 2019, there were an estimated 27,510 new cases and 11,140 deaths. Approximately 62 percent of U.S. patients with gastric cancer are diagnosed at advanced disease. Metastatic gastric cancer (mGC) is associated with a five-year survival rate of about 5 percent.7

In the U.S., standard chemotherapy regimens for advanced gastric cancer include fluoropyrimidines, platinum derivatives, and taxanes (with ramucirumab), or irinotecan. After failure of first- and second-line therapies, subsequent treatment options are limited.

About Gastroesophageal Junction Cancer
Gastroesophageal junction cancer is a type of cancer that begins in cells located near the gastroesophageal junction, the area where the esophagus connects to the stomach.8 It remains a significant clinical problem that is increasing in incidence and is associated with a poor prognosis. The majority of patients present with advanced disease, and less than 50 percent undergo curative treatment.9

About Futibatinib (TAS-120)
Futibatinib (TAS-120) is an investigational, oral, potent, selective, and irreversible small-molecule inhibitor of FGFR1, 2, 3, and 4 being studied as a potential treatment for patients with advanced solid tumors, including cholangiocarcinoma, who were previously treated with chemotherapy or other therapies including other FGFR inhibitors. Futibatinib selectively and irreversibly binds to the ATP binding pocket of FGFR 1-4 resulting in the inhibition of FGFR-mediated signal transduction pathways, reduced tumor cell proliferation and increased tumor cell death in tumors with FGFR1-4 genomic aberrations.

About LONSURF10

LONSURF is an oral nucleoside antitumor agent discovered and developed by Taiho Pharmaceutical Co., Ltd. LONSURF consists of a thymidine-based nucleoside analog, trifluridine, and the thymidine phosphorylase (TP) inhibitor, tipiracil, which increases trifluridine exposure by inhibiting its metabolism by TP. Trifluridine is incorporated into DNA, resulting in DNA dysfunction and inhibition of cell proliferation.

Since 2015, Taiho Pharmaceutical and Servier have been in an exclusive license agreement for the co-development and commercialization of LONSURF in Europe and other countries outside of the United States, Canada, Mexico, and Asia.

Indications and Use
LONSURF is indicated for the treatment of adult patients with:

metastatic colorectal cancer previously treated with fluoropyrimidine-, oxaliplatin- and irinotecan-based chemotherapy, an anti-VEGF biological therapy, and if RAS wild-type, an anti-EGFR therapy
metastatic gastric or gastroesophageal junction adenocarcinoma previously treated with at least two prior lines of chemotherapy that included a fluoropyrimidine, a platinum, either a taxane or irinotecan, and if appropriate, HER2/neu-targeted therapy.
IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS

Severe Myelosuppression:

LONSURF caused severe and life‑threatening myelosuppression (Grade 3‑4) consisting of neutropenia (38%), anemia (18%), thrombocytopenia (5%), and febrile neutropenia (3%). Two patients (0.2%) died due to neutropenic infection. A total of 12% of LONSURF‑treated patients received granulocyte‑colony stimulating factors. Obtain complete blood counts prior to and on day 15 of each cycle of LONSURF and more frequently as clinically indicated. Withhold LONSURF for febrile neutropenia, absolute neutrophil count less than 500/mm3, or platelets less than 50,000/mm3. Upon recovery, resume LONSURF at a reduced dose as clinically indicated.

Embryo‑Fetal Toxicity:

LONSURF can cause fetal harm when administered to a pregnant woman. Advise pregnant women of the potential risk to the fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 6 months after the final dose.

USE IN SPECIFIC POPULATIONS

Lactation: It is not known whether LONSURF or its metabolites are present in human milk. There are no data to assess the effects of LONSURF or its metabolites on the breast‑fed infant or the effects on milk production. Because of the potential for serious adverse reactions in breast‑fed infants, advise women not to breastfeed during treatment with LONSURF and for 1 day following the final dose.

Male Contraception: Because of the potential for genotoxicity, advise males with female partners of reproductive potential to use condoms during treatment with LONSURF and for at least 3 months after the final dose.

Geriatric Use: Patients 65 years of age or over who received LONSURF had a higher incidence of the following compared to patients younger than 65 years: Grade 3 or 4 neutropenia (46% vs 32%), Grade 3 anemia (22% vs 16%), and Grade 3 or 4 thrombocytopenia (7% vs 4%).

Hepatic Impairment: Do not initiate LONSURF in patients with baseline moderate or severe (total bilirubin greater than 1.5 times ULN and any AST) hepatic impairment. Patients with severe hepatic impairment (total bilirubin greater than 3 times ULN and any AST) were not studied. No adjustment to the starting dose of LONSURF is recommended for patients with mild hepatic impairment.

Renal Impairment: No adjustment to the starting dosage of LONSURF is recommended in patients with mild or moderate renal impairment (CLcr of 30 to 89 mL/min). Reduce the starting dose of LONSURF for patients with severe renal impairment (CLcr of 15 to 29 mL/min) to a recommended dosage of 20 mg/m2.

ADVERSE REACTIONS

Most Common Adverse Drug Reactions in Patients Treated With LONSURF (≥5%): The most common adverse drug reactions in LONSURF‑treated patients vs placebo‑treated patients with mCRC, respectively, were asthenia/fatigue (52% vs 35%), nausea (48% vs 24%), decreased appetite (39% vs 29%), diarrhea (32% vs 12%), vomiting (28% vs 14%), infections (27% vs 16%), abdominal pain (21% vs 18%), pyrexia (19% vs 14%), stomatitis (8% vs 6%), dysgeusia (7% vs 2%), and alopecia (7% vs 1%). In metastatic gastric cancer or gastroesophageal junction (GEJ), the most common adverse drug reactions, respectively were, nausea (37% vs 32%), decreased appetite (34% vs 31%), vomiting (25% vs 20%), infections (23% vs 16%) and diarrhea (23% vs 14%).

Pulmonary emboli occurred more frequently in LONSURF‑treated patients compared to placebo: in mCRC (2% vs 0%) and in metastatic gastric cancer and GEJ (3% vs 2%).

Interstitial lung disease (0.2%), including fatalities, has been reported in clinical studies and clinical practice settings in Asia.

Laboratory Test Abnormalities in Patients Treated With LONSURF: The most common laboratory test abnormalities in LONSURF‑treated patients vs placebo-treated patients with mCRC, respectively, were anemia (77% vs 33%), neutropenia (67% vs 1%), and thrombocytopenia (42% vs 8%). In metastatic gastric cancer or GEJ, the test abnormalities, respectively, were neutropenia (66% vs 4%), anemia (63% vs 38%), and thrombocytopenia (34% vs 9%).

Data from NantHealth’s GPS Cancer platform reveals increased opportunities for HER2 directed therapy in colorectal cancer patients

On January 25, 2020 NantHealth, Inc.(NASDAQ: NH), a next-generation, evidence-based, personalized healthcare company, reported Results of a fifty-gene breast cancer RNA subtype classifier applied to 167 colorectal cancer (CRC) patients during a poster session at the 2020 Gastrointestinal Cancer Symposium sponsored by the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) (Press release, NantHealth, JAN 25, 2020, View Source [SID1234553531]).

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The Symposium, held at the Moscone West Building in San Francisco, CA from January 23-25, provides evidence-based teaching methods and cutting-edge learning science to a diverse audience of leaders in oncology education, doctors and care teams.

NantHealth’s presentation utilized data on whole exome (WES) DNA tumor and paired germline and matched deep whole transcriptomic sequencing (RNA-Seq) to identify a higher percentage of CRC patients with HER2 signaling than conventional methods of immunohistochemistry (IHC) or fluorescence in-situ hybridization (FISH). ERBB2 (HER2) gene expression was evaluated using NantOmics Nant50 gene classifier, which separates patients into subgroups that have been well established in breast cancer. The application of this tool to colorectal cancer proved surprising with greater than expected HER2 positive patients with a normally expected distribution of CMS classification (consensus molecular subtype in CRC). This finding suggests a possible utility for this tool in a new clinical setting. In addition, the HER2 enriched group did not show differentially expressed mutations in other targetable genes such as PIK3CA and BRAF, highlighting the potential importance of HER2 targeting in this population.

"Our analysis shows that conventional testing methods may miss potentially actionable HER2 signaling in CRC patients," said Sandeep "Bobby" Reddy, MD, Chief Medical Officer, NantHealth. "The significant difference suggests that up to 40% more patients may be eligible for HER2 directed therapies, which has implications for drug development and clinical trials."

Title: "Results of a fifty-gene breast cancer RNA subtype classifier applied to 167 colorectal cancer (CRC) patients"

Authors: Sandeep K. Reddy, M.D., Tara Elisabeth Seery, M.D., Christopher W. Szeto, Ph.D.

Poster Session and Number: Poster session C (Board #A14)

Location: Moscone West Building

Date and Time: January 25, 2020, 6:30-7:55 AM PT and 12:15-1:45 PM PT

NantHealth’s Eviti Connect Data Shows Recycling of Chemotherapy and Biologics for Advanced CRC Patients More Common Than Switching to Drug Regimens with Alternative Mechanism of Action

On January 25, 2020 NantHealth, Inc. (NASDAQ: NH), a next-generation, evidence-based, personalized healthcare company, reported new real-world data on treatment patterns for patients with advanced colorectal cancer (CRC) during a poster session at the 2020 Gastrointestinal Cancer Symposium sponsored by the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) (Press release, NantHealth, JAN 25, 2020, View Source [SID1234553530]).

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The Symposium, held at the Moscone West Building in San Francisco, CA from January 23-25, provides evidence-based teaching methods and cutting-edge learning science to a diverse audience of leaders in oncology education, doctors and care teams.

NantHealth’s presentation examined therapeutic preferences and treatment patterns among advanced CRC patients using data from NantHealth’s Eviti Connect, an evidence-based treatment intelligence and web-based oncology decision support platform. Detailed information from 6,325 treatment plans was analyzed to identify treatment patterns using regorafenib and trifluridine + tipiracil for advanced CRC patients as third-line of therapy. National Comprehensive Cancer Network (NCCN) guidelines state that regorafenib and trifluridine+tipiracil are both treatment options for patients who have progressed through all available regimens.

Across all 6,325 treatment plans submitted for this patient population, regorafenib (n=217) or trifluridine+tipiracil (n=144) was the submitted treatment in 361 (5.5%) of the treatment plans, making them the 9th and 13th most frequently requested drugs (excluding growth factors, anti-emetics, and leucovorin) in this setting. While the total number of treatment plans for regorafenib was higher than that for trifluridine+tipiracil, the submission of trifluridine+tipiracil has increased over time, consistent with the latter drug’s more recent introduction into the market.

"Our analysis shows that recycling of chemotherapy and biologics in the late line setting is common and occurs more frequently than switching to a drug regimen with an alternative mechanism of action," said William A. Flood, MD, MS, Chief Medical Officer for Eviti, NantHealth. "As results cannot be fully explained by clinical trial outcome differences, NCCN guidelines preferences, or HEOR measures, we must delve deeper into why these therapeutic patterns exist to further our mission of optimizing patient outcomes and enabling value-based care in oncology. The uncertainty of what constitutes the ‘best’ treatment for this patient population provides an excellent opportunity to employ available data to guide patient-centered decision making and value-based care initiatives."

Title: "Real world data on treatment patterns of advanced CRC in 3rd line and beyond"

Authors: William A. Flood MD MS, Neil Margolis Ph.D., Vlad Kozlovsky, Sandeep K. Reddy MD

Abstract #56, Poster Session and Number: C – Anal and Colorectal Cancer

Location: Moscone West Building, Level 1, West Hall

Date and Time: January 25, 2020, 6:30-7:55 AM PT and 12:15-1:45 PM PT

"Our Eviti platform enables access to near-real time data on physician behavior which can provide unique and critical information to pharma, payers, and provider networks to optimize treatment strategies," said Sandeep "Bobby" Reddy, MD, Chief Medical Officer, NantHealth.

Researchers ID Promising 2-Drug Combo for Resistant Breast Cancer

On January 24, 2019 The Simmons Comprehensive Cancer Center reported constantly finding drug combinations that help fight drug-resistant cancers (Press release, The Simmons Comprehensive Cancer Center, JAN 24, 2020, View Source [SID1234553752]). Researchers at the UT Southwestern Medical Center appeared to have found a new one using already approved drugs .

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The investigators were studying data from a "molecularly guided trial" in which breast cancer patients with HER2 mutations received neratinib (Puma Biotechnology’s Nerlynx), which is a HER2 inhibitor. If the disease progressed despite treatment, the researchers sequenced the DNA of the tumors. They found in the laboratory that an effective approach to battling eventual resistance to neratinib was another drug, everolimus (Novartis’ Afinitor). Everolimus is a TORC1 inhibitor often used to treat other forms of breast cancer.

"This finding may give clinicians an effective response to neratinib resistance," said Carlos L. Arteaga, director of the Simmons Cancer Center at UT Southwestern and corresponding author of the research. "That could make a real difference for patients with breast, ovarian, lung, and other cancers harboring HER2 mutations."

HER2 mutations are known to drive breast cancer and other cancers. The researchers focused on a signaling network driven by TORC1. The network is the pathway where HER2-mutant cancers develop resistance to neratinib.

"We consistently noted activation of TORC1 signaling as a mechanism of resistance to neratinib across different types of HER2-mutant cancers," said Dhivya Sudhan, a postdoctoral research fellow at the Harold C. Simmons Comprehensive Cancer Center. "Different cancer types used different strategies to escape neratinib, but they all converged on TORC1 signaling."

They evaluated the research in data from clinical trials across the country as well as in neratinib-resistant cells and tumors grown in the laboratory. Some patients, they found, already had a mutation that could possibly activate the TORC1 pathway. Others developed it. Both groups could potentially benefit from everolimus, which would extend the patient’s ability to respond to neratinib.

At this time the combination worked in cell lines, in organoids developed from patient-derived tumors, and in mice with the HER2 mutant tumors. They hope to begin testing the two-drug combo in human clinical trials.

The research was published in the journal Cancer Cell.

Earlier this week, researchers at the Broad Institute of MIT and Harvard tested about 4,518 drugs on 578 human cancer cell lines. They discovered that almost 50 had previously unrecognized anti-cancer properties. The drugs ranged from treatments for diabetes, inflammation, alcoholism and arthritis in dogs.

"We thought we’d be lucky if we found even a single compound with anti-cancer properties, but we were surprised to find so many," said Todd Golub, chief scientific officer and director of the Cancer Program at the Broad.

The research leveraged the Broad’s Drug Repurposing Hub. This Hub is made up of more than 6,000 existing drugs and molecules the U.S. Food and Drug Administration (FDA) has either already approved or have been shown to be safe in clinical trials. At the time the group conducted their study, there were 4,518 compounds in the Hub.

"Most existing cancer drugs work by blocking proteins, but we’re finding that compounds can act through other mechanisms," Steven Corsello said. Corsello is an oncologist at Dana-Farber Cancer Institute, founder of the Drug Repurposing Hub, member of the Golub lab and first author of the study, which was published in the journal Nature Cancer.

For example, some of the drugs activated a protein or stabilized a protein-protein interaction. Almost a dozen of the non-cancer drugs killed cancer cells expressing the PDE3A protein by stabilizing the PDE3A and SLFN12 protein interaction. This was an unknown mechanism.

Many of the drugs killed cancer cells by interacting with a previously unrecognized molecular target. One example is the drug tepoxalin, used to treat osteoarthritis in dogs. But the drug killed cancer cells by interacting with an unknown target in cancer cells that overexpress the MDR1 protein, which is linked to resistance to chemotherapy drugs.

The researchers were further able evaluate the cell line’s genomic features and predict which drugs could kill each cell line. Those genomic features included mutations and methylations levels, which were available in the CCLE database.

Protein AKAP8 suppresses breast cancer metastasis

On January 24, 2020 Baylor College of Medicine reported that protein naturally produced in the body has been found to suppress breast cancer metastasis in animal models of human tumors. Researchers led by Baylor College of Medicine also found that high levels of this protein, AKAP8, predicts a better survival for breast cancer patients (Press release, Baylor College of Medicine, JAN 24, 2020, View Source [SID1234553751]).

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The findings, in the current edition of the journal Nature Communications, show that AKAP8 inhibits metastasis by interfering with the production of proteins that promote metastatic behavior in cells, and suggest strategies that may help treat metastatic cancer in the future.

"Our laboratory investigates cellular mechanisms that regulate breast cancer metastasis. In a previous study we provided the first evidence that alternative splicing, a cellular process that enables cells to switch between different forms of the same protein, can functionally control tumor metastasis," said corresponding author Dr. Chonghui Cheng, associate professor at the Lester and Sue Smith Breast Center, of molecular and human genetics and of molecular and cellular biology at Baylor.

Alternative splicing is a natural cellular process that helps cells conduct many functions, such as wound healing and embryonic development. Through alternative splicing, cells can make a large number of proteins from a limited number of genes. It would be like putting together a number of different outfits by combining in different ways a limited number of pieces of clothing. In humans, around 95 percent of all genes are processed through alternative splicing. Just recently has this process also been shown to be involved in cancer.

In that pioneering study that brought alternative splicing to the field of cancer research, Cheng and her colleagues showed that of the two distinct forms of the protein CD44 that can be produced by alternative splicing, named CD44s and CD44v, only the former contributed to cancer cell survival. These findings have been confirmed by other reports about breast cancer and also other types of cancer.

In the current study, the researchers further investigated how alternative splicing contributes to cancer metastasis by looking for proteins that regulate alternative splicing events linked to metastasis.

AKAP8 helps keep cells in a non-metastatic state
Cheng and her colleagues screened cells looking for proteins functioning as alternative splicing modulators that prevented cells from becoming metastatic. They identified a set of proteins that were potentially key for tumor metastasis regulation and focused on AKAP8.

"We studied AKAP8 in metastatic breast cancer animal model systems of cancer cells from human patients," Cheng said. "We found that depletion of the AKAP8 protein in patient cancer cells promoted breast cancer metastasis in these mouse models. Furthermore, providing an external source of AKAP8 inhibited metastasis."

Taking it all together, the results support AKAP8 as an important regulator of alternative splicing events linked to tumor metastasis. It is not only able to predict metastatic breast cancer outcomes in patients, but also can inhibit metastatic breast cancer progression in animal models.

Cheng and her colleagues continued their investigations to determine how AKAP8 mediated its metastasis-suppressing effects. They discovered that, in addition to modulating alternative splicing of CD44, AKAP8 also regulated the alternative splicing of another protein called CLSTN1. In this case, of the two forms of CLSTN1, named CLSTN1S and CLSTN1L, AKAP8 tipped the balance toward the production of the former, which was associated with preventing cells from progressing toward a metastatic state. This was a previously unknown function of CLSTN1.

"We think that modulators of alternative splicing participate in a delicate balancing act of many different cellular proteins, such as CD44 and CLSTN1. Two types of modulators play a part in keeping the balance. One type, like AKAP8, modulates alternative splicing toward the production of proteins that help cells remain in a normal state. The other type tips the balance toward proteins that promote metastatic transformation," Cheng said. "If the balance is disturbed, tumor progression can be promoted. By investigating how the balance is kept and the factors that disturb the balance, we hope to understand a new layer of regulation of tumor metastasis and gain insights that could lead to treatments for metastatic cancer, a deadly disease."

Other contributors to this work include Xiaohui Hu, Samuel E. Harvey, Rong Zheng, Jingyi Lyu, Caitlin L. Grzeskowiak and Kenneth L. Scott at Baylor; and Emily Powell and Helen Piwnica-Worms at The University of Texas MD Anderson Cancer Center, Houston.

This research was supported in part by grants from the US National Institutes of Health (5F30CA196118, R01 CA182467, R01GM110146 and R35GM131876) and CPRIT Scholar in Cancer Research grant RR160009.