[Treatment Strategies for HER2-Positive Metastatic Colorectal Cancer].

HER2-positive metastatic colorectal cancer occurs in 2-4% of all colorectal cancers, about 5% in RAS wild-type colorectal cancer, and only 0.2-1.4% in RAS mutant colorectal cancer. The TRIUMPH trial was conducted in Japan for patients with HER2-positive colorectal cancer, and its results led to the approval of the combination therapy of pertuzumab and trastuzumab for the treatment of HER2-positive unresectable advanced or recurrent colorectal cancer that has progressed during chemotherapy in March 2022 in Japan. In the field of colorectal cancer, the development of new HER2-targeted drugs such as antibody-drug conjugates and bispecific antibodies is ongoing, and future developments are expected to be of interest.

Fecal microbiota in patients with a stoma decreases anaerobic bacteria and alters taxonomic and functional diversities.

Colorectal cancer (CRC) is one of the most common malignant diseases. Generally, stoma construction is performed following surgery for the resection of the primary tumor in patients with CRC. The association of CRC with the gut microbiota has been widely reported, and the gut microbiota is known to play an important role in the carcinogenesis, progression, and treatment of CRC. In this study, we compared the microbiota of patients with CRC between with and without a stoma using fecal metagenomic sequencing data from SCRUM-Japan MONSTAR-SCREEN, a joint industry-academia cancer research project in Japan. We found that the composition of anaerobes was reduced in patients with a stoma. In particular, the abundance of Alistipes, Akkermansia, Intestinimonas, and methane-producing archaea decreased. We also compared gene function (e.g., KEGG Orthology and KEGG pathway) and found that gene function for methane and short-chain fatty acids (SCFAs) production was underrepresented in patients with a stoma. Furthermore, a stoma decreased Shannon diversity based on taxonomic composition but increased that of the KEGG pathway. These results suggest that the feces of patients with a stoma have a reduced abundance of favorable microbes for cancer immunotherapy. In conclusion, we showed that a stoma alters the taxonomic and functional profiles in feces and may be a confounding factor in fecal microbiota analysis.

Molecular Basis of HER2-Targeted Therapy for HER2-Positive Colorectal Cancer.

Human epidermal growth factor receptor 2 (HER2) amplification has emerged as a biomarker in colorectal cancer (CRC), occurring in 1-4% of metastatic CRC (mCRC). In addition to conventional methods, such as immunohistochemistry and fluorescence in situ hybridization, next-generation sequencing-based tissue or circulating tumor DNA analysis has recently been used to identify HER2 amplification and assess HER2 overexpression. Prospective clinical trials have demonstrated the efficacy of HER2-targeted therapies in HER2-positive mCRC. The TRIUMPH study, a phase II study of dual HER2 antibodies, i.e., pertuzumab plus trastuzumab, demonstrated promising efficacy for patients with HER2-positive mCRC confirmed by tissue-and/or blood-based techniques, which led to the regulatory approval of this combination therapy in Japan. The mechanisms associated with efficacy and resistance have also been explored in translational studies that incorporate liquid biopsy in prospective trials. In particular, HER2 copy number and co-alterations have repeatedly been reported as biomarkers related to efficacy. To improve the therapeutic efficacy of the current strategy, many clinical trials with various HER2-targeted agents are ongoing. This review discusses the molecular basis of HER2-targeted therapeutic strategies for patients with HER2-positive mCRC.

Feasibility of a modified search, coagulation, and clipping method with and without the use of polyglycolic acid sheets and fibrin glue for preventing delayed bleeding after gastric endoscopic submucosal dissection.

BACKGROUND: Methods have been developed for preventing delayed bleeding (DB) after gastric endoscopic submucosal dissection (GESD). However, none of the methods can completely prevent DB. We hypothesized that DB could be prevented by a modified search, coagulation, and clipping (MSCC) method for patients at low risk for DB and by combining the use of polyglycolic acid sheets and fibrin glue with the MSCC method (PMSCC method) for patients at high risk for DB (antibleeding [ABI] strategy). This study assessed the technical feasibility of this novel strategy. METHOD: We investigated 123 lesions in 121 consecutive patients who underwent GESD in Kushiro Rosai Hospital between April 2018 and January 2020. The decision for continuation or cessation of antithrombotic agents was based on the Guidelines for Gastroenterological Endoscopy in Patients Undergoing Antithrombotic Treatment. RESULTS: Oral antithrombotic agents were administered to 28 patients (22.8%). The en bloc R0 resection rate was 98.4%. The MSCC method and the PMSCC method for preventing DB were performed in 114 and 9 lesions, respectively. The median time of the MSCC method was 16 min, and the median speed (the resection area divided by the time of method used) was 3.6 cm2/10 min. The median time of the PMSCC method was 59 min, and the median speed was 1.3 cm2/10 min. The only delayed procedural adverse event was DB in 1 (0.8%) of the 123 lesions. CONCLUSIONS: The ABI strategy is feasible for preventing DB both in patients at low risk and in those at high risk for DB after GESD, whereas the PMSCC method may be necessary for reduction of time.

Impact of single-heterozygous UGT1A1 on the clinical outcomes of irinotecan monotherapy after fluoropyrimidine and platinum-based combination therapy for gastric cancer: a multicenter retrospective study.

BACKGROUND: It is unclear whether the UGT1A1 status, single heterozygous (SH) or wild type (WT), is associated with the efficacy and toxicity of irinotecan monotherapy in advanced gastric cancer (AGC). We investigated the association between clinical outcomes (efficacy and safety) and UGT1A1 status in patients who received irinotecan monotherapy. METHODS: We evaluated AGC patients who received irinotecan monotherapy between January 2011 and December 2017. Efficacy was assessed according to overall survival (OS) and progression-free survival (PFS). Toxicity was graded using the Common Toxicity Criteria for Adverse Events (version 4.0). RESULTS: A total of 100 patients were evaluated (62 and 38 patients with UGT1A1 WT and SH, respectively). In the WT and SH groups, the irinotecan dose was reduced in 19 (30.6%) and 18 (47.2%) patients (p = 0.135), respectively; treatment was delayed due to adverse events (AEs) in 19 (30.6%) and 13 (34.2%) patients (p = 0.826), respectively; the median PFS was 3.15 and 3.25 months (HR, 0.734; 95% CI 0.465-1.158; p = 0.184), respectively; and the median OS was 10.4 and 7.26 months (HR, 1.137; 95% CI 0.752-1.721; p = 0.543), respectively. Severe hematological AEs (Grade ≥ 3) were significantly more frequent in the SH group than in the WT group (63% vs. 36%; p = 0.008), while severe non-hematological AEs was not significantly different (16.0% vs. 6.5%; p = 0.173). CONCLUSION: There was no significant difference in the efficacy of irinotecan monotherapy between UGT1A1 WT and UGT1A1 SH, but UGT1A1 SH was associated with a high frequency of severe hematological toxicity.

Pericardial tamponade during pembrolizumab treatment in a patient with advanced lung adenocarcinoma: A case report and review of the literature.

Several studies have demonstrated increased pericardial effusion during anti-PD-1 immunotherapy, and treatment in patients who have developed pericardial tamponade is controversial. In this study, we describe a 63-year-old woman with stage IVA lung adenocarcinoma given pembrolizumab as a first-line therapy. After four cycles of pembrolizumab treatment, the patient suddenly developed a pericardial tamponade. Although pericardial effusion was increased, her tumor lesions were reduced. After an emergency pericardiocentesis, she continued the pembrolizumab therapy without recurrent pericardial effusions for three months until the primary tumor and lymph node metastasis progressed. Nine months after the pericardiocentesis, the patient died of progressive lung cancer, but pericardial effusion did not recur throughout the treatment course. This case study suggests that pembrolizumab therapy can be continued with a strict follow-up in some patients with pembrolizumab-induced pericardial tamponade. KEY POINTS: • Significant findings of the study Our patient developed pericardial tamponade during pembrolizumab treatment but continued pembrolizumab treatment after emergency pericardiocentesis without recurrent pericardial effusions. • What this study adds Pembrolizumab treatments may be resumed with a strict follow-up in some patients with treatment-related pericardial tamponade.

Feasibility of a new ligation using the double-loop clips technique without an adhesive agent for ulceration after endoscopic submucosal dissection of the colon (with video).

BACKGROUND AND AIMS: Several ligation techniques for ulceration after endoscopic submucosal dissection (ESD) have been reported, but none have been established for clinical use because of technical complexity and the need for expensive equipment. Therefore, the technical feasibility of a new ligation method using the double-loop clips (D-L clips) technique without an adhesive agent for ulceration after ESD of the colon was assessed. METHODS: Among 35 patients who underwent ESD of the colon in Kushiro Rosai Hospital between April 2019 and September 2019, 26 patients who underwent ligation using the D-L clips technique for the post-ESD ulcer bed were included in this retrospective study. Continuation or cessation of antithrombotic agents was based on the Guidelines for Gastroenterological Endoscopy in Patients Undergoing Antithrombotic Treatment. RESULTS: The rate of en bloc R0 resection was 97.1%, the median length of the resected specimen was 3.2 cm (interquartile range [IQR], 2.8-3.8 cm), and the complete ligation rate was 88.5% (23 of 26). Excluding patients with lesion sites in the rectum below the peritoneal reflection, the complete ligation rate was 95.5% (21 of 22). The median duration of the ligation procedure was 20 minutes (IQR, 16-24 minutes). The only delayed procedural adverse event was post-ESD coagulation syndrome in 1 patient. Incomplete ligation was significantly more frequent in patients with lesion sites in the inferior rectal valve/anal verge area (P = .0269). CONCLUSIONS: Ligation using the D-L clips technique without an adhesive agent is feasible for closing ulceration after ESD of the colon, whereas other techniques may be necessary for lesions in the rectum below the peritoneal reflection.

Interferon-free therapy with sofosbuvir plus ribavirin for successful treatment of genotype 2 hepatitis C virus with lichen planus: a case report.

Hepatitis C virus (HCV) infection remains the main cause of liver disease and can lead to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HCV may also develop extrahepatic manifestations in the skin, eyes, joints, kidneys, nervous system, and immune system. In fact, several studies reported that up to 70% of HCV patients experienced extrahepatic manifestations. Lichen planus (LP), which is an immune system disorder that is triggered by viral infections, allergens, and stress, can affect the skin, mouth, nails, and scalp. The association of LP with HCV has been reported, but the effect of HCV treatment on LP remission is controversial. We encountered a 53-year-old man with HCV genotype 2a and LP that were successfully treated with sofosbuvir and ribavirin for 12 weeks. After treatment, he achieved sustained virological response against HCV and remission of erosive LP lesions on the lip. In the era of interferon (IFN)-based treatment for HCV, exacerbation of autoimmune diseases is a common adverse event. Therefore, use of an IFN-free regimen of direct-acting antivirals for HCV might prevent the extrahepatic manifestation of an immune disorder.

P53- and mevalonate pathway-driven malignancies require Arf6 for metastasis and drug resistance.

Drug resistance, metastasis, and a mesenchymal transcriptional program are central features of aggressive breast tumors. The GTPase Arf6, often overexpressed in tumors, is critical to promote epithelial-mesenchymal transition and invasiveness. The metabolic mevalonate pathway (MVP) is associated with tumor invasiveness and known to prenylate proteins, but which prenylated proteins are critical for MVP-driven cancers is unknown. We show here that MVP requires the Arf6-dependent mesenchymal program. The MVP enzyme geranylgeranyl transferase II (GGT-II) and its substrate Rab11b are critical for Arf6 trafficking to the plasma membrane, where it is activated by receptor tyrosine kinases. Consistently, mutant p53, which is known to support tumorigenesis via MVP, promotes Arf6 activation via GGT-II and Rab11b. Inhibition of MVP and GGT-II blocked invasion and metastasis and reduced cancer cell resistance against chemotherapy agents, but only in cells overexpressing Arf6 and components of the mesenchymal program. Overexpression of Arf6 and mesenchymal proteins as well as enhanced MVP activity correlated with poor patient survival. These results provide insights into the molecular basis of MVP-driven malignancy.

Lysophosphatidic acid activates Arf6 to promote the mesenchymal malignancy of renal cancer.

Acquisition of mesenchymal properties by cancer cells is critical for their malignant behaviour, but regulators of the mesenchymal molecular machinery and how it is activated remain elusive. Here we show that clear cell renal cell carcinomas (ccRCCs) frequently utilize the Arf6-based mesenchymal pathway to promote invasion and metastasis, similar to breast cancers. In breast cancer cells, ligand-activated receptor tyrosine kinases employ GEP100 to activate Arf6, which then recruits AMAP1; and AMAP1 then binds to the mesenchymal-specific protein EPB41L5, which promotes epithelial-mesenchymal transition and focal adhesion dynamics. In renal cancer cells, lysophosphatidic acid (LPA) activates Arf6 via its G-protein-coupled receptors, in which GTP-Gα12 binds to EFA6. The Arf6-based pathway may also contribute to drug resistance. Our results identify a specific mesenchymal molecular machinery of primary ccRCCs, which is triggered by a product of autotaxin and it is associated with poor outcome of patients.

AMAP1 as a negative-feedback regulator of nuclear factor-κB under inflammatory conditions.

NF-κB is a major transcriptional factor regulating many cellular functions including inflammation; therefore, its appropriate control is of high importance. The detailed mechanism of its activation has been well characterized, but that of negative regulation is poorly understood. In this study, we showed AMAP1, an Arf-GTPase activating protein, as a negative feedback regulator for NF-κB by binding with IKKß, an essential kinase in NF-κB signaling. Proteomics analysis identified AMAP1 as a binding protein with IKKß. Overexpression of AMAP1 suppressed NF-κB activity by interfering the binding of IKKß and NEMO, and deletion of AMAP1 augmented NF-κB activity. The activation of NF-κB induced translocation of AMAP1 to cytoplasm from cell membrane and nucleus, which resulted in augmented interaction of AMAP1 and IKKß. These results demonstrated a novel role of AMAP1 as a negative feedback regulator of NF-κB, and presented it as a possible target for anti-inflammatory treatments.

Non-activated APJ suppresses the angiotensin II type 1 receptor, whereas apelin-activated APJ acts conversely.

Apelin and its G-protein-coupled receptor APJ are potent regulators of the cardiovascular system. Recent studies have suggested that apelin-APJ reverses the function of angiotensin II (Ang II)-the Ang II type 1 receptor (AT(1)). However, the mechanism remains unclear because of the accumulating evidences that apelin-APJ may contribute to both cardioprotection and pathological progression. In human embryonic kidney 293 cells, we found that coexpression with APJ significantly suppressed the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) induced by Ang II-AT(1), whereas apelin abolished this attenuation through activated APJ independently of its heterodimerization. Pretreatment with the Gi/o-specific inhibitor pertussis toxin (PTX) restituted the ERK1/2 phosphorylation level similar to that found with AT(1) and APJ coexpression without apelin stimulation. In contrast, coexpression of the beta-2-adrenergic receptor or the pharmacologically non-activated Ang II type 2 receptor (AT(2)) pretreated with the AT(2)-specific antagonist, PD123319, did not affect ERK1/2 phosphorylation through AT(1). Pretreatment with 30 nM of the AT(1) blocker (ARB) TA-606A suppressed 50% of the AT(1)-mediated ERK1/2 phosphorylation, whereas 30 nM of TA-606A achieved 75% suppression when the non-activated APJ was coexpressed without ligand or PTX. However, 120 nM of TA-606A failed to reach the target phosphorylation when it was coexpressed with activated APJ with apelin. Based on these results, we demonstrated that non-activated APJ may suppress Ang II-AT(1) signaling, whereas this ligand-independent function was diminished with apelin activation. These results may be relevant to the potential contribution of apelin-APJ to ARB treatment in the clinical realm.

The (pro)renin receptor is cleaved by ADAM19 in the Golgi leading to its secretion into extracellular space.

The (pro)renin receptor ((P)RR), which is a recently discovered molecule of the renin-angiotensin system, plays an important role in the development of cardiovascular diseases. However, the molecular properties and the subcellular distribution of (P)RR remain controversial. In this study, (P)RR-Venus in Chinese hamster ovary (CHO) cells ((P)RR-Venus-CHO) or endogenous (P)RR in human vascular smooth muscle cells (VSMC) were constitutively cleaved without any stimulation, and secretion of the amino-terminal fragment (NTF-(P)RR) into the media was determined using western blot analysis. Immunofluorescent analysis showed robust expression of (P)RR in the endoplasmic reticulum (ER) or the Golgi but not in the plasma membrane. Moreover, we identified ADAM19, which is expressed in the Golgi, as one of cleaving proteases of (P)RR. Transfected ADAM19 evoked the shedding of (P)RR, whereas transfected dominant negative ADAM19 suppressed it. Although (P)RR contains a furin cleavage site, neither the furin-deficient LoVo cells nor furin inhibitor-treated VSMC lost NTF-(P)RR in the media. The secreted NTF-(P)RR induced the renin activity of prorenin in the extracellular space. We describe that (P)RR is mainly localized in the subcellular organelles, such as the ER and Golgi, and (P)RR is cleaved by ADAM19 in the Golgi resulting in two fragments, NTF-(P)RR and CTF-(P)RR. These results may suggest that (P)RR is predominantly secreted into the extracellular space.

New perspectives on secretion of (pro)renin receptor into extracellular space.

(Pro)renin receptor is a new molecule of the renin-angiotensin system. The (pro)renin receptor binds both renin and prorenin leading to protease activity. Furthermore, the binding of renin/prorenin to (pro)renin receptor activates intracellular signaling. Although these studies show the classical function of the (pro)renin receptor on the plasma membrane as a receptor, subcellular distribution and extracellular secretion of (pro)renin receptor remained controversial until recently when Cousin et al. reported possible existence of the soluble form of (pro)renin receptor. Chinese hamster ovary (CHO) cells transfected with human (pro)renin tagged with Venus showed bands at 74 kDa and 35 kDa without any stimulation in Western blot analysis. Moreover, these cells secreted a 29 kDa form, which was the amino-terminal fragment of the (pro)renin receptor. In immunofluorescent staining, (pro)renin receptor tagged with Venus was mainly stained on the endoplasmic reticulum and in vesicle-like structures, but not on the plasma membrane. These data suggest that the (pro)renin receptor may be cleaved in the intracellular compartments of cells and secreted into the extracellular space.