Enhanced G1 arrest and apoptosis via MDM4/MDM2 double knockdown and MEK inhibition in wild-type TP53 colon and gastric cancer cells with aberrant KRAS signaling.

Murine double minute homolog 2 (MDM2) is an oncoprotein that induces p53 degradation via ubiquitin-ligase activity. MDM4 cooperates with MDM2-mediated p53 degradation, directly inhibiting p53 transcription by binding to its transactivation domain. Our previous study reported that the simultaneous inhibition of MDM2 and MDM4 using nutlin-3 (an inhibitor of the MDM2-p53 interaction) and chimeric small interfering RNA with DNA-substituted seed arms (named chiMDM2 and chiMDM4) more potently activated p53 than the MDM2 or MDM4 inhibitor alone and synergistically augmented antitumor effects in various types of cancer cells with the wild-type (wt) TP53. Recently, the synergism of MDM2 and mitogen-activated protein kinase kinase (MEK) inhibitors has been demonstrated in wt TP53 colorectal and non-small cell lung cancer cells harboring mutant-type (mt) KRAS. The current study examined whether chiMDM4 augmented the synergistic antitumor effects of MDM2 and MEK inhibition using chiMDM2 or nutlin-3 and trametinib, respectively. ChiMDM2 and trametinib used in combination demonstrated a synergistic antitumor activity in HCT116 and LoVo colon cancer cells, and SNU-1 gastric cancer cells harboring wt TP53 and mt KRAS. Furthermore, chiMDM4 synergistically enhanced this combinational effect. Similar results were observed when nutlin-3 was used instead of chiMDM2. MDM4/MDM2 double knockdown combined with trametinib treatment enhanced G1 arrest and apoptosis induction. This was associated with the accumulation of p53, suppression of phosphorylated-extracellular signal-regulated kinase 2, inhibition of retinoblastoma phosphorylation, suppression of E2F1-activated proteins, and potent activation of pro-apoptotic proteins, such as Fas and p53 upregulated modulator of apoptosis. The results inidcated that the triple inhibition of MDM4, MDM2 and MEK exerted a potent antitumor effect in wt TP53 colon and gastric cancer cells with mt KRAS. Simultaneous activation of p53 and inhibition of aberrant KRAS signaling may be a rational treatment strategy for gastrointestinal tumors.

MDM4 as a Prognostic Factor for Patients With Gastric Cancer With Low Expression of p53.

BACKGROUND/AIM: The oncoproteins murine double minute (MDM) 2 and MDM4 inactivate tumor-suppressor protein p53. Their mutual relationship with the prognosis of gastric cancer (GC) remains unknown. PATIENTS AND METHODS: Expression of MDM2, MDM4, and p53 in tumors of 241 patients with GC were evaluated immunohistochemically. Effects of overexpression of MDM4 on tumor-growth properties and sensitivity to cytotoxic drugs were investigated using NUGC4 human GC cell line. RESULTS: High expression of p53 was associated with poor overall survival in the whole population. Among 173 patients with low expression of p53 (implying nonmutation), high expression of MDM4 was an independent factor of poor prognosis in both stage I-III and IV, but of MDM2 was not. MDM4-transduced NUGC4 cells formed twice as many colonies and had a higher 50% inhibitory concentration for 5-fluorouracil and oxaliplatin than did the control cells. CONCLUSION: MDM4 expression is a factor conferring poor prognosis in patients with GC with low expression of p53 and may confer drug resistance.

Retrospective analysis for the efficacy and safety of nivolumab in advanced gastric cancer patients according to ascites burden.

BACKGROUND: Nivolumab is a standard later-line therapy for advanced gastric cancer (AGC). However, few reports exist about its efficacy and safety in patients with massive ascites. METHODS: We retrospectively collected clinical data from 72 AGC patients who received nivolumab administration at least once from Oct 2017 to Feb 2019 and studied their clinical outcomes dividing into two groups: 50 patients with no or localized ascites in the pelvic cavity or liver surface (LAB: low ascites burden) and 22 patients with massive ascites (HAB: high ascites burden). RESULTS: Median overall survival (OS) was 5.3 months (95% CI 3.4-7.3) in the LAB group and 2.5 months (95% CI 0.0-5.0) in the HAB group. Multivariate Cox regression analysis for OS revealed blood neutrophil-to-lymphocyte ratio (hazard ratio 0.40, 95% CI 0.20-0.83, p = 0.013) as an independent prognostic factor. Response rates in the patients with measurable lesions were 16% (7/43) and 8% (1/12) in the LAB and HAB groups, respectively. Ascites decreased or disappeared in 6 HAB patients (27%) and these responders had a prolonged OS of median 9.7 months (95% CI 3.6-15.8). The median time to ascites response was 1.3 months (95% CI 0.8-1.9). These responders have lower neutrophil-to-lymphocyte ratios than 5.0 at the start of nivolumab. Immune-related adverse events occurred in 23% of HAB and 18% of LAB patients. CONCLUSIONS: Nivolumab could improve massive ascites and confer survival benefit for some AGC patients. Considering a similar incidence of immune-related adverse events, it would be a recommended treatment option for AGC with massive ascites.

Optimal Maintenance Strategy for First-Line Oxaliplatin-Containing Therapy with or without Bevacizumab in Patients with Metastatic Colorectal Cancer: A Meta-Analysis.

PURPOSE: Maintenance therapy after oxaliplatin withdrawal is useful in patients with metastatic colorectal cancer (mCRC). This study aimed to investigate the timing of discontinuation or reintroduction of oxaliplatin and the optimal maintenance therapy regimen for survival. MATERIALS AND METHODS: PubMed and conference abstracts were searched to select phase II and III trials of first-line oxaliplatin-containing therapy with or without bevacizumab using maintenance therapy for mCRC. Correlations of median overall survival (OS) with induction therapy regimens, induction therapy duration, maintenance therapy regimens (fluoropyrimidine plus bevacizumab [FP+Bev], FP/Bev alone, and no treatment), and oxaliplatin reintroduction were investigated using correlation and weighted multivariate regression analyses. RESULTS: Twenty-two treatment arms were analyzed, including 2,581 patients. The maintenance therapy regimen FP+Bev showed the strongest correlation with a prolonged OS (Spearman's partial correlation coefficient=0.42), and the other three variables correlated weakly with the OS. The maintenance therapy regimen significantly interacted with the induction chemotherapy duration (p=0.019). The predicted OS for FP+Bev crossed the lines of FP/Bev alone at 18 weeks of induction therapy, and of no treatment at 23 weeks. The corresponding OS at 12 and 27 weeks of induction therapies were 28.6 and 24.2 months for FP+Bev, 25.9 and 28.8 months for FP/Bev alone, and 20.5 and 27.5 months for no treatment. CONCLUSION: The optimal maintenance therapy regimen for the OS is a continuous induction therapy as long as possible followed by FP/Bev alone and switching to FP+Bev within approximately 4 months if induction therapy is discontinued.

Augmented antitumor activity of 5-fluorouracil by double knockdown of MDM4 and MDM2 in colon and gastric cancer cells.

Inactivation of the TP53 tumor suppressor gene is essential during cancer development and progression. Mutations of TP53 are often missense and occur in various human cancers. In some fraction of wild-type (wt) TP53 tumors, p53 is inactivated by upregulated murine double minute homolog 2 (MDM2) and MDM4. We previously reported that simultaneous knockdown of MDM4 and MDM2 using synthetic DNA-modified siRNAs revived p53 activity and synergistically inhibited in vitro cell growth in cancer cells with wt TP53 and high MDM4 expression (wtTP53/highMDM4). In the present study, MDM4/MDM2 double knockdown with the siRNAs enhanced 5-fluorouracil (5-FU)-induced p53 activation, arrested the cell cycle at G1 phase, and potentiated the antitumor effect of 5-FU in wtTP53/highMDM4 human colon (HCT116 and LoVo) and gastric (SNU-1 and NUGC-4) cancer cells. Exposure to 5-FU alone induced MDM2 as well as p21 and PUMA by p53 activation. As p53-MDM2 forms a negative feedback loop, enhancement of the antitumor effect of 5-FU by MDM4/MDM2 double knockdown could be attributed to blocking of the feedback mechanism in addition to direct suppression of these p53 antagonists. Intratumor injection of the MDM4/MDM2 siRNAs suppressed in vivo tumor growth and boosted the antitumor effect of 5-FU in an athymic mouse xenograft model using HCT116 cells. These results suggest that a combination of MDM4/MDM2 knockdown and conventional cytotoxic drugs could be a promising treatment strategy for wtTP53/highMDM4 gastrointestinal cancers.

Interstitial lung disease associated with trastuzumab monotherapy: A report of 3 cases.

We herein report 3 cases of female patients with breast cancer who developed interstitial lung disease (ILD) during trastuzumab monotherapy in an adjuvant setting. Prior chemotherapy included 4 cycles of epirubicin and cyclophosphamide in patients 1 and 2, and 4 cycles of docetaxel, cyclophosphamide and trastuzumab in patient 3. Patient 1 presented with a cough and fever after the fourth cycle of trastuzumab. Patient 2 experienced rapid deterioration of oxygen saturation without subjective symptoms within 3 h of the first administration of trastuzumab. Patient 3 was unexpectedly diagnosed with organizing pneumonia in a scheduled computed tomography (CT) scan after the first course of trastuzumab. Based on clinical data, such as decreased PaO2 level, increased serum levels of KL-6 and/or lactate dehydrogenase, and findings on chest CT, these patients were diagnosed with drug-induced ILD. Considering the clinical course, trastuzumab was incriminated as the cause of ILD, particularly in patients 1 and 2. All 3 patients improved due to the timely diagnosis, discontinuation of trastuzumab and immediate administration of corticosteroid therapy. Although ILD is a rare adverse event associated with trastuzumab, it may cause rapid deterioration without preceding symptoms. Close observation and early diagnosis are required to avoid an unfavorable outcome.

Correlations of survival with progression-free survival, response rate, and disease control rate in advanced biliary tract cancer: a meta-analysis of randomised trials of first-line chemotherapy.

BACKGROUND: The need to promote novel drug development for advanced biliary tract cancer (ABTC) has emphasised the importance of determining whether various efficacy end points can act as surrogates for overall survival (OS). METHODS: We conducted a literature search of randomised trials of first-line chemotherapy for ABTC and investigated correlations between efficacy end points and OS using weighted linear regression analysis. The ratios of the median OS, median progression-free survival (PFS), response rate, and disease control rate in each trial were used to summarise treatment effects. The surrogate threshold effect (STE), which was the minimum treatment effect on PFS required to predict a non-zero treatment effect on OS, was calculated. RESULTS: Seventeen randomised trials with 36 treatment arms were identified, and a sample size of 2148 patients with 19 paired arms was analysed. The strongest correlation between all evaluated efficacy end points was observed between median OS and median PFS ratios (r(2)=0.66). In trials with gemcitabine-containing therapies and targeted agents, the r(2)-values were 0.78. The STE was estimated at 0.83 for all trials and 0.81 for trials with gemcitabine-containing therapies, and was not calculated for trials with targeted agents. CONCLUSIONS: The median PFS ratio correlated well with the median OS ratio, and may be useful for planning a clinical trial for novel drug development.

Successful Treatment with Modified FOLFOX6 and Panitumumab in a Cecal Cancer Patient Undergoing Hemodialysis.

Combination chemotherapy of mFOLFOX6 (5-fluorouracil, leucovorin, and oxaliplatin) plus panitumumab, a fully human monoclonal antibody against epidermal growth factor receptor (EGFR), is one of the standard treatments for metastatic colorectal cancer (mCRC) without KRAS mutation. A few reports suggested no need of dose adjustment of cetuximab, a similar chimeric anti-EGFR antibody, in patients with renal impairment. However, panitumumab combined with cytotoxic drugs for hemodialysis patients has not been reported. We herein report a case of a hemodialysis mCRC patient successfully treated with mFOLFOX6 and panitumumab combination therapy.

Utility of epirubicin-incorporating micelles tagged with anti-tissue factor antibody clone with no anticoagulant effect.

Tissue factor (TF), an initiator of the extrinsic blood coagulation cascade, is overexpressed in different types of cancer. Tissue factor overexpression is also known as a poor prognostic factor in pancreatic cancer. We recently developed anti-TF antibody (clone1849)-conjugated epirubicin-incorporating micelles (NC-6300), and reported that this anti-TF1849-NC-6300 showed enhanced antitumor activity against TF-high expressed human pancreatic cancer cells, when compared with NC-6300 alone. However, clone 1849 antibody inhibited TF-associated blood coagulation activity. We studied another anti-TF antibody, clone 1859, which had no effect on blood coagulation and prepared anti-TF1859-NC-6300. In addition, to determine the optimum size of the antibody fragment to conjugate with NC-6300, three forms of the 1859 antibody (whole IgG, F[ab']2 , and Fab') were conjugated to NC-6300. The antitumor effect of each anti-TF1859-NC-6300 was studied in vitro and in vivo, using two human pancreatic cancer cell lines, BxPC3 with high-expressed TF, and SUIT2 with low levels of TF. In vitro, all forms of anti-TF1859-NC-6300 showed higher cytocidal effects than NC-6300 in BxPC3, whereas this enhanced effect was not observed in SUIT2. Likewise, all forms of anti-TF1859-NC-6300 significantly suppressed tumor growth when compared to NC-6300 in the BxPC3, but not in the SUIT2, xenograft model. Among the three forms of conjugates, anti-TF1859-IgG-NC-6300 had a higher antitumor tendency in TF-high expressed cells. Thus, we have confirmed an enhanced antitumor effect of anti-TF1859-NC-6300 in a TF-high expressing tumor; anti-TF1859-IgG-NC-6300 could be used to simplify the manufacturing process of the antibody-micelle conjugation for future clinical studies.

Phase I study of gemcitabine, cisplatin, and S-1 combination therapy for patients with untreated advanced biliary tract cancer.

BACKGROUND: To develop a triplet regimen containing gemcitabine, cisplatin, and S-1 (GPS), we assessed the recommended dose for patients with untreated advanced biliary tract cancer in this phase I study. METHODS: Dose-limiting toxicities (DLTs) were evaluated for the following two dose levels: gemcitabine (1000 mg/m(2) for level 1 and 1200 mg/m(2) for level 2 on day 1), cisplatin (30 mg/m(2) fixed dose on day 1), and S-1 (40-60 mg/day fixed dose twice a day for 7 days), every 2 weeks until progression. DLTs for each level were evaluated in six or more patients during the first two cycles. RESULTS: A total of 18 patients were enrolled and 16 patients were evaluated. DLTs at level 1 were observed in two of 10 patients. At level 2, a DLT was observed in one of six patients. The main grade 3 or 4 treatment-related adverse events were neutropenia and leukopenia, and a few non-hematological toxicities were observed. Among 14 patients with measurable lesions, the best response rate was 50%. CONCLUSIONS: GPS with a relative dose intensity corresponding to 90% of the standard gemcitabine plus cisplatin regimen could be administered safely, and showed preliminary antitumor activity. Survival benefits will be studied subsequently.

[A retrospective analysis of cetuximab or panitumumab monotherapy for KRAS wild-type metastatic colorectal cancer in clinical practice].

We performed a retrospective study on the use of cetuximab or panitumumab alone in patients with KRAS wild-type metastatic colorectal cancer between November 2008 and February 2012. Twenty-two patients were analyzed and classified as PS 0/1 (good PS group)and PS 2/3/4 (poor PS group)with 11 patients in each group. The response rate, disease control rate, median progression-free survival, and median overall survival were 9%, 73%, 5.1 months (95%confidence interval[CI]: 1.5-8.7), and 16 months (95% CI: 8.8-24), respectively, in the good PS group, and the corresponding values in the poor PS group were 0%, 18%, 0.7 months (95% CI: 0.3-1.0), and 1.5 months (95% CI: 0.7-2.4). Grade 3 or 4 adverse events were skin toxicities (2 patients with grade 3 toxicities), panitumumab-related interstitial lung disease (1 patient with grade 4 toxicity), and cetuximab infusion-related reaction (1 patient with grade 4 toxicity). No treatment-related deaths were observed. In conclusion, the efficacy and safety of cetuximab or panitumumab monotherapy in patients with a good PS in our study were similar to those reported in previous clinical trials, whereas patients with a poor PS showed poorer outcomes.

[A case of malignant peritoneal mesothelioma with the epithelioid histological type, successfully treated with pemetrexed plus cisplatin].

A 45-year-old man presented with severe abdominal distention with massive ascites due to a diffusely disseminated peritoneal tumor. A core needle biopsy specimen was obtained from the peritoneal lesion. Histological diagnosis was epithelioid type mesothelioma. He did not choose to receive chemotherapy. For 2.5 years, he went without medical intervention, and his disease gradually progressed, leading to a worsening of his symptoms. The patient then chose to be treated with combination chemotherapy of cisplatin and pemetrexed, followed by pemetrexed alone. There was remarkable tumor shrinkage and his symptoms improved. These effects have been sustained for two years after the initial chemotherapy. Chemotherapy appears to have contributed to survival prolongation for this patient. This case exemplifies the fact that malignant peritoneal mesothelioma may progress slowly when fits with some good prognostic factors, and it is important to consider the prognostic factors.

Collagenous sprue diagnosed by double balloon endoscopy.

Double balloon endoscopy (DBE) is useful for diagnosing many intestinal diseases and for endoscopic procedures. We report a case of chronic diarrhea in a 58-year-old Japanese man. He was initially suspected to have malabsorption syndrome. DBE showed reduction of folds, scalloping, mucosal nodularity and granularity. Pathological examinations of biopsies from the jejunum showed severe villous atrophy with subepithelial collagen bands. These findings led to the final diagnosis of collagenous sprue (CS). With1 month of total parenteral nutrition followed by a low-gluten diet, his symptoms gradually improved. CS has never been reported before in Japan. DBE is useful for making a diagnosis of CS, and may be considered for patients who are suffering from diarrhea of unknown cause.

Panitumumab-induced interstitial lung disease in a case of metastatic colorectal cancer.

BACKGROUND: A Japanese postmarketing survey of panitumumab revealed that panitumumab-associated interstitial lung disease (ILD) occurred in approximately 1% (19/1767) of patients, causing death in 36.8% of these cases. CASE REPORT: We report the case of a 60-year-old Japanese man who developed ILD associated with panitumumab therapy (third-line therapy) for metastatic sigmoid colon cancer involving the liver, lymph nodes, and lungs. 2 months after the initiation of panitumumab therapy, he developed a progressive nonproductive cough, dyspnea, and a fever, and was diagnosed with ILD. Intravenous pulse methylprednisolone treatment led to quick recovery. The patient had some risk factors for ILD associated with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors. CONCLUSION: Further studies are required to elucidate the association between anti-EGFR antibodies and ILD.

Diphenylhydantoin-induced severe yet reversible anemia during pregnancy.

Diphenylhydantoin (DPH) therapy, often used in treating epileptic seizures, can cause anemia in some patients. A 26-year-old female suffered from convulsions due to encephalitis and was placed on DPH therapy. About two months after the initiation of DPH therapy, her hemoglobin level was 3.8 g/dL. Her anemia improved after the discontinuation of DPH, confirming that the anemia was caused by DPH. Pure red-cell aplasia (PRCA) combined with hemolytic anemia was indicated by results such as erythroid aplasia, an increased LDH level, and a decreased haptoglobin level. PRCA complicated by hemolytic anemia could be responsible for anemia associated with DPH.

Effects of methylprednisolone pulse on cytokine levels in Kawasaki disease patients unresponsive to intravenous immunoglobulin.

This study aimed to determine the effects of intravenous methylprednisolone pulse (IVMP) therapy on cytokine levels in patients with acute Kawasaki disease (KD) unresponsive to initial intravenous immunoglobulin (IVIG) therapy. Fifteen KD patients unresponsive to initial IVIG, 2 g/kg/day, were randomized to receive IVMP (n = 7), 30 mg/kg/day for 3 days or additional IVIG (n = 8), 2 g/kg/day, and plasma cytokine levels were compared. The fraction of febrile patients was significantly lower in the IVMP group than in the additional IVIG group on day 2 (0/7 vs. 3/8, p = 0.03), but not on day 4 and later (3/7 vs. 4/8, p = 1.00) because of recurrent fever. The prevalence of coronary lesions was similar between the two groups (2/7 vs. 2/8, p = 1.00). The ratios of plasma levels of tumor necrosis factor-alpha and monocyte chemoattractant protein-1 to those at enrollment (defined as day 1) were significantly lower in the IVMP group on day 4 (0.50 +/- 0.27 vs. 1.01 +/- 0.46, 0.53 +/- 0.39 vs. 0.93 +/- 0.44, p = 0.02 and 0.045, respectively), but not on day 7 (0.54 +/- 0.34 vs. 0.88 +/- 0.39, 0.76 +/- 0.39 vs. 0.61 +/- 0.17, p = 0.07 and 0.83, respectively). The ratios of interleukin-2 receptor, interleukin-6, and vascular endothelial cell growth factor to those at enrollment did not differ significantly between the two groups. In conclusion, for KD patients unresponsive to initial IVIG, IVMP suppresses cytokine levels faster, but subsequently similarly, compared with additional IVIG.