Familial Polyposis Research Articles

Familial adenomatous polyposis associated with malignancy

Background Familial adenomatous polyposis (FAP) is a rare genetic disorder that is inherited in an autosomal dominant fashion. This disease is caused by a germline mutation in the APC gene, but in 20-30% of cases the disease occurs due to de novo mutations. There are several forms of the disease from severe, which is characterized by a pronounced number of polyps throughout the gastrointestinal tract (GIT) to a mild (attenuated) form of FAP, with less than 100 colonic polyps. According to various scientific literature, the risk of malignancy of epithelial formations reaches 100%. Identified epithelial formations of the gastrointestinal tract will lie down for endoscopic or surgical treatment. FAP is also characterized by neoplasms of extraintestinal localization, which characterizes it as a multisystem syndrome. There is a high risk of developing congenital retinal pigment epithelium hypertrophy, bone osteoma, fibroma, angiofibroma of the nose, thyroid carcinoma, hepatoblastoma, brain tumor and pancreatic tumor. Congenital retinal hypertrophy is the earliest extraintestinal manifestation of FAP. Thyroid cancer in young people, as a rule, is diagnosed first and serves as the basis for a comprehensive endoscopic diagnosis of the gastrointestinal tract. We present a rare case of FAP in a 14-year-old child associated with malignant neoplasms of extraintestinal localizations.

Could Capsule Endoscopy Be Useful in Detection of Suspected Small Bowel Bleeding and IBD-10 Years of Single Center Experience.

A retrospective study in patients who underwent video capsule endoscopy (VCE) between 2006 and 2016 was conducted in the Clinic for gastroenterology and Hepatology, University Clinical Center of Serbia. A total of 245 patients underwent VCE. In 198 patients the indication was obscure gastrointestinal bleeding (OGIB), with 92 patients having overt and the other 106 occult bleeding. The remaining 47 patients underwent VCE due to suspected small bowel (SB) disease (i.e., Von Hippel-Lindau syndrome, familial adenomatous polyposis, Peutz Jeghers syndrome, Crohn's disease, prolonged diarrhea, abdominal pain, congenital lymphangiectasia, protein-losing enteropathy, tumors, refractory celiac disease, etc.). VCE identified a source of bleeding in 38.9% of patients (in the obscure overt group in 48.9% of patients, and in the obscure occult group in 30.2% of patients). The most common findings were angiodysplasias, tumors, Meckel's diverticulum and Crohn's disease. In the smaller group of patients with an indication other than OGIB, 38.3% of patients had positive VCE findings. The most common indication is OGIB, and the best candidates are patients with overt bleeding; patients with IBD should be evaluated in this setting.

Familial syndromes associated with testicular and paratesticular neoplasms: a comprehensive review.

A syndromic association between a subset of testicular/paratesticular neoplasms is well established. Such examples include Carney complex and large cell calcifying Sertoli cell tumor, Peutz-Jeghers syndrome and intratubular large cell hyalinizing Sertoli cell neoplasia, and VHL syndrome and clear cell papillary cystadenoma of the epididymis.However, recent studies proposed potential novel links between some testicular and paratesticular neoplasms with certain tumor syndromes. While more studies are still needed to solidify these associations, recent research suggests that a subset of Leydig cell tumors may arise in patients with hereditary leiomyomatosis and renal cell carcinoma syndrome or that some seminomas may occur in Lynch syndrome patients. Additionally, an association between testicular sex cord stromal tumors and paratesticular sarcomas with Familial adenomatous polyposis syndrome and DICER1 syndrome, respectively, has been proposed as well. This review provides a comprehensive overview of the intricate relationship between familial syndromes and associated testicular and paratesticular tumors, shedding light on their clinicopathological and molecular characteristics.

Evaluation of EGFR and COX pathway inhibition in human colon organoids of serrated polyposis and other hereditary cancer syndromes.

Serrated polyposis syndrome (SPS) presents with multiple sessile serrated lesions (SSL) in the large intestine and confers increased colorectal cancer (CRC) risk. However, the etiology of SPS is not known. SSL-derived organoids have not been previously studied but may help provide insights into SPS pathogenesis and identify novel biomarkers and chemopreventive strategies. This study examined effects of EGFR and COX pathway inhibition in organoid cultures derived from uninvolved colon and polyps of SPS patients. We also compared with organoids representing the hereditary gastrointestinal syndromes, Familial Adenomatous Polyposis (FAP) and Lynch syndrome (LS). Eighteen total organoid colon cultures were generated from uninvolved colon and polyps in SPS, FAP, LS, and non-syndromic screening colonoscopy patients. BRAF and KRAS mutation status was determined for each culture. Erlotinib (EGFR inhibitor) and sulindac (COX inhibitor) were applied individually and in combination. A 44-target gene custom mRNA panel (including WNT and COX pathway genes) and a 798-gene microRNA gene panel were used to quantitate organoid RNA expression by NanoString analysis. Erlotinib treatment significantly decreased levels of mRNAs associated with WNT and MAPK kinase signaling in organoids from uninvolved colon from all four patient categories and from all SSL and adenomatous polyps. Sulindac did not change the mRNA profile in any culture. Our findings suggest that EGFR inhibitors may contribute to the chemopreventive treatment of SSLs. These findings may also facilitate clinical trial design using these agents in SPS patients. Differentially expressed genes identified in our study (MYC, FOSL1, EGR1, IL33, LGR5 and FOXQ1) may be used to identify other new molecular targets for chemoprevention of SSLs.

Unraveling the Mystery of Desmoid Tumors: Insights From a Moroccan Tertiary Center.

Desmoid tumors (DTs) are rare, aggressive malignancies developing from clonal fibroblastic proliferation originating from soft tissues. Despite their low metastatic potential, their invasiveness towards neighboring organs and a high recurrence rate contribute significantly to morbidity and mortality, thereby impacting the quality of life of patients. Several therapeutic options are available, but standardized protocols are lacking. In this study, we reviewed 14 cases of DT retrospectively over a period of 15 years, from September 2008 to December 2023. The most prevalent tumor locations were in the extremities, and the majority of patients were female. We identified risk factors in two patients, those being surgical trauma and familial adenomatous polyposis (FAP). Half of the patients underwent surgery for DT, and two received salvage radiotherapy. Systemic therapy was used in the first and second lines and comprised of chemotherapy, endocrine therapy, and non-steroidal anti-inflammatory drugs (NSAI). Active surveillance was proposed in three patients. This is the first retrospective study to assess the characteristics of DT in Moroccan patients in a tertiary care setting. It aims to shed light on the challenges faced in treating these rare tumors in the context of a lack of therapeutic standardization.

Abstract SY07-02: Cell competition vs cell cooperation: Unlocking oncogenic potential of mutant clones in the gut

Abstract The epithelial monolayer of the intestine is one of the fastest renewing tissues of the human body. Every week, the entire epithelium is replaced by intestinal stem cells (ISCs) that reside in crypt-like structures within the monolayer. Within these crypts, a small number of ISCs continuously divide to provide all specialized cell types necessary to maintain normal intestinal homeostasis, while simultaneously competing with each other for a position within the crypt bottom. This competition, characterized by neutral loss-and-replacement events, can be drastically disturbed when one of the ISCs acquires a mutation that confers a competitive advantage. As a result, mutant ISCs will replace all normal ISCs, colonize the intestinal crypt, and facilitate the initiation of colorectal cancer (CRC). CRC development is a stepwise process characterized by the accumulation of mutations in cancer driver genes over time. Almost 80% of all CRCs present with early mutations in the tumor suppressor gene APC, leading to constitutive activation of the Wnt pathway and the formation of pre-malignant adenomas. We have previously demonstrated that, within individual crypts, Apc-mutant ISCs have a competitive advantage over normal ISCs, although the mechanism underlying this unequal competition remained unclear. Recently, we revealed that Apc-mutant ISCs in fact act as "supercompetitors" by secreting Wnt antagonists such as NOTUM, WIF1 and DKK2, that actively disadvantage neighboring wild type ISCs by forcing them do differentiate. We demonstrated that boosting wild type fitness by downstream pharmacological activation of the Wnt signaling pathway by GSK3β-inhibitor lithium rendered wild type ISCs resistant to the Wnt antagonists, reduced the number of Apc-mutant crypts, and prevented adenoma formation. Together, this work highlights that modulating cell competition between normal and mutant cells within the crypt can provide a novel approach to prevent CRC development. Our findings are particularly relevant for familial adenomatous polyposis (FAP) patients, that carry germline mutations in APC and are predisposed to the development of CRC. Based on our fundamental discoveries, we are currently performing a clinical trial to assess the chemopreventive effect of lithium on the expansion of APC-mutant clones in FAP patients [ClinicalTrials.gov: NCT05402891]. Importantly, it is becoming increasingly evident that intestinal adenomas do not form from a single Apc-mutant crypt, but require fields of multiple mutant crypts to facilitate tumor initiation. Although field cancerization by enhanced crypt fission has been observed for several oncogenic mutants in the gut (e.g. KrasG12D, PIK3CAH1047R), Apc-mutant cells are often contained within individual crypts. This indicates that multiple independent mutant clones may act cooperatively to facilitate tumorigenesis, thereby pointing towards a polyclonal origin of intestinal adenomas. Our current work investigates how Apc-mutant clones interact by modifying their local environment through reciprocal signalling with stromal and epithelial cells to escape the anatomical constraints of the crypt, thereby unlocking their oncogenic potential in the gut. Ultimately, unravelling the molecular mechanisms underlying clonal cooperation will inform potential chemoprevention strategies for CRC. Citation Format: Sanne van Neerven. Cell competition vs cell cooperation: Unlocking oncogenic potential of mutant clones in the gut [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr SY07-02.

Downregulation of ABCC3 activates MAPK signaling through accumulation of deoxycholic acid in colorectal cancer cells.

ABCC3 (also known as MRP3) is an ATP binding cassette transporter for bile acids, whose expression is downregulated in colorectal cancer through the Wnt/β-catenin signaling pathway. However, it remained unclear how downregulation of ABCC3 expression contributes to colorectal carcinogenesis. We explored the role of ABCC3 in the progression of colorectal cancer-in particular, focusing on the regulation of bile acid export. Gene expression analysis of colorectal adenoma isolated from familial adenomatous polyposis patients revealed that genes related to bile acid secretion including ABCC3 were downregulated as early as at the stage of adenoma formation. Knockdown or overexpression of ABCC3 increased or decreased intracellular concentration of deoxycholic acid, a secondary bile acid, respectively, in colorectal cancer cells. Forced expression of ABCC3 suppressed deoxycholic acid-induced activation of MAPK signaling. Finally, we found that nonsteroidal anti-inflammatory drugs increased ABCC3 expression in colorectal cancer cells, suggesting that ABCC3 could be one of the targets for therapeutic intervention of familial adenomatous polyposis. Our data thus suggest that downregulation of ABCC3 expression contributes to colorectal carcinogenesis through the regulation of intracellular accumulation of bile acids and activity of MAPK signaling.

Perceived food intolerances and its impact on diet quality in patients with an ileoanal pouch

Restorative proctocolectomy with ileal pouch-anal anastomosis is the surgical treatment of choice for patients with medically-refractory ulcerative colitis (UC) and familial adenomatous polyposis (FAP). Whilst quality of life is generally good, as many as 83% of patients associate dietary factors with the onset of symptoms(1) and around two-thirds employ some form of dietary restriction post-pouch creation(2,3). There is growing interest to understand the role of diet (as a whole) on pouch function and how it can be used therapeutically. It is imperative that we know the dietary characteristics of pouch patients before attempting to introduce strategies altering their food choice. Since there is good rationale to assess overall diet quality to identify potential avenues for targeting dietary strategies, this study aimed to examine the frequency of perceived food intolerances and diet quality in patients with an ileoanal pouch and the relationship between these two indices. In this cross-sectional study, patients with an ileoanal pouch completed a food intolerance questionnaire and a validated 297-item semi-quantitative food frequency questionnaire (Monash Comprehensive Nutritional Assessment Questionnaire). Dietary data was used to score diet quality using the 2013 Dietary Guidelines Index (DGI), a scoring system which compares how closely an individual’s dietary intake aligns with the Australian Dietary Guidelines (ADG). The DGI also comprises of 11 subcomponents (scored out of 10 respectively) based on each of the ADG guidelines and provides a total score of 110, with higher scores reflecting greater compliance to the ADG. In order to determine if perceived dietary intolerances was negatively associated with the intake of specific dietary factors, univariable and multivariable linear regression analysis of the correlation of intolerance and diet quality was performed. Of the 58 (10 FAP and 48 UC) patients studied, 81% of UC and 80% of FAP patients reported dietary intolerances. Mean total DGI score was 78 (95% CI: 74-80) of 110 in the overall pouch cohort with no differences across pouch sub-groups. However, only 5% of patients achieved a full score for food variety. Both uni- [OR −0.94 (−1.7,-0.10); p = 0.02] and multivariable analysis (adjusting for age and sex) showed that only intolerances to dairy products were associated with reduced intake of lactose-containing dairy [OR −0.29 (−1.8,-0.08); p=0.03]. No other significant correlations were found for overall or subcomponents of DGI scores. High rates of perceived food intolerances were observed in patients with an ileoanal pouch. However, only those with perceived dairy intolerances restricted their intake of lactose-containing dairy products. Additionally, patients with ileoanal pouch scored highly for overall diet quality but specific gaps in achieving better diet quality, particularly for diet variety were observed. These results provide some starting points for targeted dietary counselling to optimise nutritional health and potentially to improve pouch function these patients.

Robotic-assisted reoperative ileal pouch-anal anastomosis: robotic pouch excision and pouch revision.

Up to 20% of patients with ileal pouch will develop pouch failure, ultimately requiring surgical reintervention. As a result of the complexity of reoperative pouch surgery, minimally invasive approaches were rarely utilized. In this series, we present the outcomes of the patients who underwent robotic-assisted pouch revision or excision to assess its feasibility and short-term results. All the patients affected by inflammatory bowel diseases and familial adenomatous polyposis who underwent robotic reoperative surgery of an existing ileal pouch were included. Twenty-two patients were included; 54.6% were female. The average age at reoperation was 51 ± 16years, with a mean body mass index of 26.1 ± 5.6kg/m2. Fourteen (63.7%) had a diagnosis of ulcerative colitis at reoperation, and seven (31.8%) had Crohn's disease. The mean time to pouch reoperation was 12.8 ± 11.8years. Seventeen (77.3%) patients underwent pouch excision, and five (22.7%) had pouch revision surgery. The mean operative time was 372 ± 131min, and the estimated blood loss was 199 ± 196.7ml. The conversion rate was 9.1%, the 30-day morbidity rate was 27.3% (with only one complication reaching Clavien-Dindo gradeIIIB), and the mean length of stay was 5.8 ± 3.9days. The readmission rate was 18.2%, the reoperation rate was 4.6%, and mortality was nihil. All patients in the pouch revisional group are stoma-free. Robotic reoperative pouch surgery in highly selected patients is technically feasible with acceptable outcomes.

Genomic insights into familial adenomatous polyposis: unraveling a rare case with whole APC gene deletion and intellectual disability

A young patient diagnosed with advanced colon cancer and liver metastasis was found to have familial adenomatous polyposis (FAP) through comprehensive genomic analysis. Whole-genome array comparative genomic hybridization (aCGH) revealed germline deletions at chromosome 5q22.1-22.2 encompassing the entire APC gene. The patient and her son exhibited mild intellectual disability without developmental delay. This case highlights the need for further exploration of the characteristics associated with whole APC deletions. aCGH is a valuable tool for studying FAP and provides a detailed analysis of large deletions.

Rediversion of the Failing Ileoanal Pouch: First Step in Pouch Salvage?

Ileal pouch-anal anastomosis is a technically demanding procedure with many potential complications. Rediversion with an ileostomy is often the first step in pouch salvage; however, it may not be clear if an individual patient will undergo subsequent pouch salvage surgery. We aimed to describe the indications and short- and long-term outcomes of rediversion in our pouch registry. We queried our institutional pouch registry for patients who underwent index 2- or 3-stage IPAA and subsequent rediversion at our institution between 1985 and 2022. Pouches constructed elsewhere, rediverted elsewhere, or those patients who underwent pouch salvage/excision without prior rediversion were excluded. Patients were selected for pouch salvage according to the surgeon's discretion. Overall, 177 patients (3.4% of 5207 index pouches) were rediverted. At index pouch, median patient age was 32 years and 50.8% were women. Diagnoses included ulcerative colitis (86.4%), indeterminate colitis (6.2%), familial adenomatous polyposis (4.0%), and others (3.4%). Median time from prior ileostomy closure to rediversion was 7.2 years. Indications for rediversion were inflammatory in 98 (55.4%) and noninflammatory in 79 (44.6%) patients. After rediversion, 52% underwent pouch salvage, 30% had no further surgery, and 18.1% underwent pouch excision. The 5-year pouch survival rates for inflammatory and noninflammatory indications were 71.5% and 94.5%, respectively (P = .02). Rediversion of ileoanal pouches is a safe initial strategy to manage failing pouches and is a useful first step in pouch salvage in many patients. Subsequent salvage surgery for noninflammatory indications had a significantly higher pouch salvage rate than those rediverted for inflammatory complications.

Risk Factors of Early Age Colorectal Cancer among Patients Attending at National Institute of Cancer Research & Hospital

Background: Colorectal cancer (CRC) poses a significant public health burden worldwide, with a notable trend of increasing incidence among individuals aged 20 to 50 years. Understanding the risk factors associated with early-onset CRC is crucial for developing targeted prevention and intervention strategies, particularly in limited-resource settings. Objective: This study aimed to identify and analyze the risk factors contributing to the development of early-onset CRC in a population from a limited-resource country. Method: A comparative study was conducted among 178 CRC patients admitted to the National Institute of Cancer Research & Hospital (NICRH), Dhaka. Patients were divided into two groups: Group-A (age 20-50 years) and Group-B (age >50 years). Demographic and clinical data were collected, and statistical analyses were performed to determine associations between various risk factors and early-onset CRC. Results: The mean age of Group-A subjects was 43.6±7.1 years, significantly younger than Group-B subjects (59.2±9.3 years). Male patients constituted 69.1% of the cohort, with a statistically significant male-to-female ratio of 2.2:1. Higher BMI (≥25) was strongly associated with early-onset CRC (p<0.01). Occupations such as business and middle socioeconomic status were significantly linked to early-onset CRC. Regular exercise (>30 minutes daily) demonstrated a protective effect against CRC development. Consumption of red meat and fast food was associated with a higher risk of CRC, while regular consumption of vegetables was protective. Familial adenomatous polyposis (FAP) presence was significantly associated with early-onset CRC. Conclusions: Male sex, high BMI, specific occupations, dietary factors, and presence of FAP emerged as key risk factors for early-onset CRC. Encouraging regular exercise and promoting healthy dietary habits, particularly reducing red meat and fast-food intake, are crucial in mitigating the risk of early-onset CRC in similar populations.

Favorable clinical efficacy of cytotoxic chemotherapy in patients with progressive desmoid tumors: a retrospective real-world study.

The real-world evidence about the efficacy of cytotoxic chemotherapy in desmoid tumors is still limited. We investigated the efficacy of chemotherapy in the treatment of recurrent or progressive desmoid tumors. The patients with desmoid tumors who had received cytotoxic chemotherapy between November 2007 and June 2020 in two tertiary hospitals in Korea were reviewed. A total of 25 patients were included in the analysis. The most common primary tumor site was the intra-abdominal or pelvic cavity (56%), followed by the trunk and abdominal wall (24%), extremities (16%), and head and neck (4%). Sixty percent of the patients had familial adenomatous polyposis and 76% received doxorubicin plus dacarbazine. The objective response rate and disease control rate was 64% (95% confidence interval [CI]: 40.7-82.8) and 96% (95% CI: 77.2-99.9), respectively. With the median follow-up time of 55months (95% CI: 41.0-68.2), the 3-year PFS rate was 65% (95% CI: 41.1-80.5), and the 3-year OS rate was 89% (95% CI: 63.8-97.3). Grade 3 or 4 hematologic adverse events were reported in 14 patients, all of which were manageable. Our real-world evidence suggests that doxorubicin-based cytotoxic chemotherapy can be an effective treatment option for recurrent and progressive desmoid tumors with respect to favorable clinical outcomes.

Abstract 4780: TRAIL-inducing imipridone ONC201/TIC10 demonstrates anti-neoplastic effects in colonic adenoma-derived organoids

Abstract Background: Colorectal cancer (CRC) is the second leading cause of cancer-related death inthe United States and screening is the most effective method to reduce mortality. Chemoprevention, which aims to prevent CRC through eradication or prevention of precursor colonic adenomas, represents an alternative strategy to address this problem. The imipridone dordaviprone (ONC201) has been shown to induce apoptosis in cancer cells through both upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and the integrated stress response. More recently, we have shown that ONC201 induces TRAIL and apoptosis in a dose-dependent manner and reduces adenoma formation in the Apcmin/+ CRC mouse model. We hypothesized that ONC201 would similarly enhance human colonic adenoma cell death through both TRAIL-dependent and TRAIL-independent mechanisms. We therefore evaluated the effects of ONC201 in two adenoma-derived organoid lines: one developed from an adenoma obtained from an individual with familial adenomatous polyposis (FAP) and the second from a sessile serrated adenoma (SSA). Methods: Sensitivity of the FAP and SSA organoid lines to ONC201 was assessed using CellTiter-Glo® luminescent cell viability assay. Organoids were plated in triplicates and treated with ONC201 (concentration ranging from 0 uM to 20 uM). Results were analyzed after 72 hours of incubation. Western blotting was performed on lysates generated from organoids treated with either 1.69 uM DMSO, 1.69 uM ONC201, or 3.38 uM ONC201 for FAP and 1.23 uM DMSO, 1.23 uM ONC201, or 2.46 uM ONC201 for SSA for 0, 24, or 48 hours. Co-culture experiments were performed with the adenoma-derived organoids (dyed using blue CMAC dye) and human NK-92MI cells (dyed with green CMFDA dye) treated with either 845 nM DMSO, 845 nM ONC201, or 1.69 uM ONC201 for FAP and 615 nM DMSO, 615 nM ONC201, or 1.23 uM ONC201 for SSA. Fluorescent images following administration of red live/dead dye were performed using DAPI, FITC, and cherry red channels on ImageXpress® at 0, 24, 48, and 72hours. Results: ONC201 demonstrated antineoplastic effects in adenoma-derived FAP and SSA organoids. Half maximal inhibitory concentrations (IC50) of ONC201 in FAP and SSA organoids were 1.69 uM and 1.23 uM, respectively. As was noted in rodent studies, the mechanism of action of ONC201 appears to be mediated through modulation of multiple pathways including the TRAIL pathway (TRAIL and DR5 were both upregulated) and the integrated stress response (ATF4 was upregulated). Co-culture with NK cells revealed an increase in NK-mediated organoid cell death. The ability of ONC201 to enhance NK-mediated killing is still being evaluated. Further analysis of the effects of ONC201 on stemness markers and on T-cell-mediated organoid cell killing are currently underway and may reveal other potential biomarkers and chemopreventive strategies for ONC201. Citation Format: Alexis J. Lannigan, Jasper Chan, Maximilian Schwermann, Lanlan Zhou, Varun V. Prabhu, Michael Dame, Dean Brenner, Wafik S. El-Deiry, Alexander G. Raufi. TRAIL-inducing imipridone ONC201/TIC10 demonstrates anti-neoplastic effects in colonic adenoma-derived organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4780.

Abstract 5276: Immunomodulatory activity of intermittent low-dose erlotinib plus sulindac: Implications for hereditary and sporadic colorectal cancer

Abstract A once-weekly optimized dosing regimen of erlotinib (ERL) in the polyposis in rat colon (Pirc) model [1] was a reliable predictor of antitumor efficacy in familial adenomatous polyposis (FAP) patients [2]. Pirc rats are increasingly used as a translational tool for FAP studies. Based on transcriptomic data from FAP patients receiving ERL plus sulindac (SUL) vs. placebo [3], we determined the timing of changes in interferon-γ signaling in Pirc adenomas, while performing additional dose titration. In rats that were given ERL administered at 5 mg per kilogram of body weight through oral gavage (two times a week) and that received a diet containing 125 parts per million of SUL, a regimen referred to as SUL125+ERL5x2, significant suppression of tumor growth was observed. This combination represented half of the standard of care SUL dose and about one-quarter of the ERL dose in FAP patients. In adenomas collected after one year of treatment from SUL125+ERL5x2 treated rats, the expression of genes related to the major histocompatibility complex (MHC) class I (β2m, Cnx, Psmb8 and Tap1) and MHC class II (RT1-A2, Cd74, RT-1Bb, Cd74, and Ciita) was increased, compared to vehicle controls, excluding a subset of adenomas that remained resistant. Through the use of multiplex mass cytometry (CyTOF), an increase in tumor-infiltrating CD4+ T cells was observed in adenomas from the SUL125+ERL5x2 treatment group. Administration of single or combined agents increased CD68+ cells and reduced the presence of Foxp3+ and Arg1+ cells in Pirc adenomas. The natural history of adenomatous colon polyps indicated an increase in MHC gene expression as tumors increased in size; however, this trend reversed markedly in fully occluding lesions. Additionally, expression of MHC-related factors increased in Pirc colon adenoma and murine colon carcinoma cells treated with ERL±SUL, resulting in enhanced CD8+ T-cell activation and IL-2 secretion. In conclusion, treatment with intermittent low doses of ERL±SUL increased MHC gene expression and induced changes in the immune cell component in the tumor microenvironment of Pirc rat adenomas. A subset of non-responsive adenomas could benefit from additional immunopreventive approaches, with implications for possible clinical applications in both hereditary and sporadic colorectal cancer.

Abstract 1479: ABCC3 (MRP3)-mediated export of deoxycholic acid regulates MAPK signaling in colorectal adenoma and adenocarcinoma

Abstract ABCC3 (also known as MRP3) is an ATP binding cassette transporter and it works as a bile acids transporter. We previously elucidated that ABCC3 expression is downregulated in colorectal cancer through the Wnt/β-catenin signaling pathway. However, it remained unclear how downregulation of ABCC3 expression contributes to colorectal carcinogenesis. We here explored the role of ABCC3 in the progression of colorectal cancer-in particular, focusing on the regulation of bile acid export. First, we performed experiments with clinical samples of familial adenomatous polyposis (FAP) patients to confirm whether ABCC3 expression is already downregulated in colorectal adenomas. Next, we investigated the effect of ABCC3 expression on intracellular bile acid concentrations using ABCC3 knockdown and overexpression colorectal cancer cell lines (HT-29, SW620). The intracellular concentration of deoxycholic acid, which is known to have carcinogenic effects, was verified with fluorescently labeled deoxycholic acid. Then, we tested whether activation of oncogenic signaling by deoxycholic acid is affected by ABCC3 expression changes. Finally, we examined the effect of nonsteroidal anti-inflammatory drugs (NSAIDs), which have been suggested to inhibit the carcinogenesis of FAP, on the expression of ABCC3 in experiments with colorectal cancer cell lines. Gene and protein expression analysis of colorectal adenomas isolated from FAP patients revealed that ABCC3 were downregulated as early as at the stage of adenoma formation, and many other genes related to bile acid efflux were also downregulated. Knockdown or overexpression of ABCC3 increased or decreased intracellular concentration of deoxycholic acid in colorectal cancer cells, respectively. Forced expression of ABCC3 suppressed deoxycholic acid-induced activation of MAPK signaling. Finally, we found that several NSAIDs increased ABCC3 expression in colorectal cancer cells, suggesting that ABCC3 could be one of the targets for therapeutic intervention of FAP. Our data thus suggest that downregulation of ABCC3 expression contributes to colorectal carcinogenesis through the regulation of intracellular accumulation of bile acids and activity of MAPK signaling. Citation Format: Yukihiro Sato, Minoru Kobayashi, Masahiro Ohira, Ryo Funayama, Masamitsu Maekawa, Hideaki Karasawa, Shinobu Ohnuma, Michiaki Unno, Keiko Nakayama. ABCC3 (MRP3)-mediated export of deoxycholic acid regulates MAPK signaling in colorectal adenoma and adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1479.

Abstract 3872: Multi-ancestral origins of colorectal lesionsMulti-ancestral origins of colorectal lesions

Abstract The widely accepted paradigm that cancer initiation is a monoclonal event has not been definitively resolved. In sporadic cancers this is due to the requirement for longitudinal sampling to study this occult process, which occurs over years to decades. Individuals with familial adenomatous polyposis (FAP) possess a germline APC mutation, leading to hundreds of colonic polyps in adolescence and a 100% lifetime risk of colorectal cancer. Resected colons from FAP patients contain normal mucosa, benign and dysplastic polyps that embed the natural history of colorectal tumorigenesis at different points of malignant progression. Through genome sequencing of 127 independent polyps or mucosa samples from six FAP patients, we characterized the genomic landscape, relative timing of somatic alterations, and clonal dynamics in normal, dysplastic, and invasive colon tissue. Comparison with multi-region sequencing data from FAP patients and sporadic colorectal adenomas and carcinomas indicates similar molecular profiles, with canonical cancer driver genes present across benign and dysplastic premalignant lesions and shared mutational orders. Pairwise sample comparisons and phylogenetic reconstructions revealed extensive heterogeneity and subclonal sharing within a patient’s benign and dysplastic lesions, irrespective of location in the colon. These data imply that polyps were initiated from multiple cells from distinct lineages whose most recent common ancestor arose during development. We corroborate these findings using a mechanistic mathematical model, which infers polyclonality in 100% of benign and 83% of dysplastic samples. Based on these findings, we propose a conceptual model of the multi-ancestral origin of intestinal malignancies. Citation Format: Ryan O. Schenck, Aziz Khan, Aaron Horning, Edward D. Esplin, Debra Van Egeren, HTAN–FAP Consortium, William Greenleaf, James M. Ford, Michael P. Snyder, Christina Curtis. Multi-ancestral origins of colorectal lesionsMulti-ancestral origins of colorectal lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3872.

Abstract 5635: TPM4 overexpression promotes colon epithelial cell tumorigenesis in vitro and correlates with human colon tumor progression in vivo

Abstract Because colon cancer still exerts a heavy burden on human health, we are interested in identifying very early events in colon epithelial cell tumorigenesis in order to develop strategies to treat and possibly prevent colon carcinogenesis. We hypothesize that aberrant expression of genes involved in crypt-luminal colon epithelial cell migration, needed for proliferative, undifferentiated stem cells at the crypt bottom to mature into growth arrested, mature effector cells near the lumen, may disrupt normal differentiation and initiate events that can trigger the transition from a normal to premalignant state in colon epithelial cells. Forced upregulation of tropomyosin 4 (TPM4), an actin-binding protein that exerts many effects on contractility and migration, prevents certain aspects of Caco2 maturation induced by contact inhibition of growth, including increased expression of the digestive enzyme sucrose isomaltase and glutathione S-transferase alpha 1. Furthermore, TPM4.2-overexpressing cells exhibit numerous morphological abnormalities. Compared to untransfected Caco2 cells and empty-vector stable transfectant controls, TPM4.2-overexpressing Caco2 cell clones elaborate aberrant thin membrane protrusions and expanded membrane ruffles. Particularly striking are defective maintenance of dome structures at middle (day 14) and late (day 21) time points of induced differentiation in TPM4.2-overeexpressing clones. We further hypothesize that TPM4 is overexpressed in human colon tumors, particularly at early stages of tumorigenesis. In order to test this hypothesis, we examined TPM4 RNA expression in datasets obtained from human colon tissue at premalignant as well as tumorigenic stages. TPM4 trends toward overexpression in premalignant, relative to normal, human colon tissue (uninvolved mucosa from patients with familial adenomatous polyposis, or FAP) and is significantly overexpressed in adenocarcinoma tissue relative to normal controls. Interestingly, TPM4 overexpression may be more pronounced at earlier, rather than later, stages of adenocarcinoma. Our results suggest that aberrant TPM4 overexpression in colon epithelial cells can promote adoption of a tumorigenic state. Certain aspects of Caco2 cell maturation are disrupted by forced TPM4 overexpression during induced differentiation, and TPM4 overexpression correlates with early stages of colon tumorigenesis. Misregulation of TPM4 gene expression may therefore represent a critical molecular event that can block normal differentiation and induce early events in colon epithelial cell tumorigenesis. TPM4 expression level may therefore prove to be a useful biomarker that can, along with other diagnostics, help to determine tumorigenic progression in human colon tissue and to develop novel strategies to prevent colon cancer and treat it at early stages. Citation Format: Giulio Ferrero, Barbara Pardini, Alessio Naccarati, Michael Papetti. TPM4 overexpression promotes colon epithelial cell tumorigenesis in vitro and correlates with human colon tumor progression in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5635.

Microenvironmental changes in familial adenomatous polyposis during colorectal cancer carcinogenesis

Familial adenomatous polyposis (FAP) is a heritable disease that increases the risk of colorectal cancer (CRC) development because of heterozygous mutations in APC. Little is known about the microenvironment of FAP. Here, single-cell RNA sequencing was performed on matched normal tissues, adenomas, and carcinomas from four patients with FAP. We analyzed the transcriptomes of 56,225 unsorted single cells, revealing the heterogeneity of each cell type, and compared gene expression among tissues. Then we compared the gene expression with that of sporadic CRC. Furthermore, we analyzed specimens of 26 FAP patients and 40 sporadic CRC patients by immunohistochemistry. Immunosuppressiveness of myeloid cells, fibroblasts, and regulatory T cells was upregulated even in the early stages of carcinogenesis. CD8+ T cells became exhausted only in carcinoma, although the cytotoxicity of CD8+ T cells was gradually increased according to the carcinogenic step. When compared with those in the sporadic CRC microenvironment, the composition and function of each cell type in the FAP-derived CRC microenvironment had differences. Our findings indicate that an immunosuppressive microenvironment is constructed from a precancerous stage in FAP.

Juvenile polyposis syndrome (review)

Juvenile polyposis syndrome (JPS), a rare disease with an autosomal dominant mode of inheritance, which is characterized with the presence of multiple polyps in various parts of the gastrointestinal tract, mainly in the colon. The detection of adenomatous polyps in patients with JPS, in addition to juvenile ones, significantly complicates the differential diagnosis with familial adenomatous polyposis, in which it is necessary to perform a radical surgery — proctocolectomy. Only in 40-60% of cases, pathogenic variants of the SMAD4 and BMPR1A genes can be identified, each of which is characterized with its own clinical manifestations. Treatment options for patients with JPS include endoscopic and surgical; however, the decision-making algorithm, as well as the timing of postoperative follow-up, are not evaluated in Russian clinical guidelines. The rare occurrence of this syndrome, difficulties in endoscopic diagnosis and morphological verification, as well as limitations in determining the molecular genetics cause of the disease demonstrate the need for further research.