Comprehensive clinical and molecular characterization of claudin 18.2 expression in advanced gastric or gastroesophageal junction cancer

BACKGROUND

We conducted comprehensive clinical and molecular characterization of claudin 18.2 expression (CLDN18.2) in advanced gastric or gastroesophageal junction cancer (GC/GEJC).

PATIENTS AND METHODS

Patients with advanced GC/GEJC who received systemic chemotherapy from October 2015 to December 2019 with available tumor specimens were analyzed. We evaluated clinicopathological features of CLDN18.2 expression with four molecular subtypes: mismatch repair deficient, Epstein-Barr virus-positive, human epidermal growth factor receptor 2-positive, and others. In addition, programmed death-ligand 1 (PD-L1) combined positive score (CPS), genomic alterations, and the expression of immune cell markers were assessed. Clinical outcomes of standard first- or second-line chemotherapy and subsequent anti-programmed cell death protein 1 (anti-PD-1) therapy were also investigated according to CLDN18.2 expression.

RESULTS

Among 408 patients, CLDN18.2-positive (moderate-to-strong expression in ≥75%) was identified in 98 patients (24.0%) with almost equal distribution in the four molecular subtypes or CPS subgroups. CLDN18.2-positive was associated with Borrmann type 4, KRAS amplification, low CD16, and high CD68 expression. Overall survival with first-line chemotherapy was not significantly different between CLDN18.2-positive and -negative groups [median 18.4 versus 20.1 months; hazard ratio 1.26 (95% confidence interval 0.89-1.78); P = 0.191] regardless of stratification by PD-L1 CPS ≥5. Progression-free survival and objective response rates of first- and second-line chemotherapy, and anti-PD-1 therapy also showed no significant differences according to CLDN18.2 status.

CONCLUSIONS

CLDN18.2 expression in advanced GC/GEJC was associated with some clinical and molecular features but had no impact on treatment outcomes with chemotherapy or checkpoint inhibition. CLDN18.2-positive also had no impact on overall survival. This information could be useful to interpret the results from currently ongoing clinical trials of CLDN18.2-targeted therapies for advanced GC/GEJC and to consider a treatment strategy for CLDN18.2-positive GC/GEJC.

Binding of collagen gene products with titanium oxide

Titanium is the only metal to which osteoblasts can adhere and on which they can grow and form bone tissue in vivo, resulting in a strong bond between the implant and living bone. This discovery provides the basis for the universal medical application of Ti. However, the biochemical mechanism of bond formation is still unknown. We aimed to elucidate the mechanism of bond formation between collagen, which constitutes the main organic component of bone, and TiO₂, of which the entire surface of pure Ti is composed. We analysed the binding between the soluble collagen and TiO₂ by chromatography with a column packed with Ti beads of 45 µm, and we explored the association between collagen fibrils and TiO₂ (anatase) powders of 0.2 µm. We ran the column of chromatography under various elution conditions. We demonstrated that there is a unique binding affinity between Ti and collagen. This binding capacity was not changed even in the presence of the dissociative solvent 2M urea, but it decreased after heat denaturation of collagen, suggesting the contribution of the triple-helical structure. We propose a possible role of periodically occurring polar amino acids and the collagen molecules in the binding with TiO₂.

Impact of the 12-gene recurrence score assay on deciding adjuvant chemotherapy for stage II and IIIA/B colon cancer: the SUNRISE-DI study

BACKGROUND

Recent advances in adjuvant chemotherapy for early colon cancer have widened physicians' recommendations on the regimen and duration (3 or 6 months) of the treatment. We conducted this prospective study to evaluate whether the 12-gene recurrence score (12-RS) assay affected physicians' recommendations on adjuvant treatment selection.

PATIENTS AND METHODS

Patients with stage IIIA/IIIB or stage II colon cancer were enrolled. After the patients discussed adjuvant treatment with their treating physicians, the physicians filled in the questionnaire before assay indicating the treatment recommendation. When the 12-RS assay results were available, the physicians again filled in the questionnaire after assay. The primary endpoint was the rate of change in treatment recommendations from before to after the assay, with a threshold rate of change being 20%. Patients with stage IIIA/B to II were enrolled in a ratio of 2 : 1.

RESULTS

Overall, the treatment recommendations changed in 40% of cases after obtaining 12-RS assay results. Recommendations were changed in 45% (80/178; 95% confidence interval, 37% to 53%; P < 0.001) and 30% (29/97; 95% confidence interval, 21% to 40%; P < 0.001) of patients with stage IIIA/B and II colon cancer, respectively. Patients with stage IIIA/B cancer had significantly more change than those with stage II cancer (P = 0.0148). From before to after the 12-RS assay, the percentage of patients whose physicians reported being confident in their treatment recommendations significantly increased from 54% to 81% in stage IIIA/B (P < 0.001) and from 65% to 83% in stage II (P < 0.001).

CONCLUSION

Our study confirmed the usefulness of the 12-RS assay in aiding the physician-patient decision-making process for tailoring adjuvant chemotherapy for stage IIIA/B colon cancer.

Phosphorylated chitin increased bone formation when implanted into rat calvaria with the Ti-device

BACKGROUND

Previously we found that a group of phosphorylated proteins (SIBLINGs) in bone binds with the Ti-device, and increases the early bone formation around the Ti-implants remarkably. From these results, we explained the biochemical mechanism of a strong bond between living bone and Ti, which was discovered by Brånemark and colleagues. For the clinical application of our findings, we need a large amount of these proteins or their substitutes.

OBJECTIVE

We aimed to create a new molecule that equips with essential functions of SIBLINGs, Ti-binding, and bone enhancement around the Ti implant.

METHODS

We chemically phosphorylated chitin and obtained a soluble form of phosphorylated chitin (P-chitin). In this solution, we immersed the Ti-devices of web-form (TW) which we previously developed and obtained the P-chitin coated TWs. Then we tested the P-chitin coated TWs for their calcification ability in vitro, and bone enhancing ability in vivo, by implanting them into rat calvaria. We compared the P-chitin coated TW and the non-coated TW in regard to their calcification and bone enhancing abilities.

RESULTS

Ti-devices coated with phosphorylated-chitin induced a ten times higher calcification in vitro at 20 days, and four times more elevated amount of bone formation in vivo at two weeks than the uncoated Ti-device.

CONCLUSIONS

Phosphorylated chitin could be a partial substitute of bone SIBLING proteins and are clinically applicable to accelerate bone formation around the Ti implants, thereby achieving the strong bond between living bone and Ti.

Comprehensive analyses using next-generation sequencing and immunohistochemistry enable precise treatment in advanced gastric cancer

BACKGROUND

In advanced gastric cancer (AGC), most clinical trials are designed on the basis of protein expression or gene amplification of specific genes. Recently, next-generation sequencing (NGS) allowed us to comprehensively profile the tumor gene status. This study aimed to elucidate the profiling between gene alterations and protein expression in AGC to aid in future clinical trials on AGC.

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tumor samples from 121 stage III/IV gastric cancer patients were examined for protein expression of tyrosine kinase receptors (RTKs; ERBB2, EGFR, c-MET, and FGFR2) using immunohistochemistry (IHC). Furthermore, 409 cancer-related genes were sequenced to detect mutations and copy number variations using NGS.

RESULTS

Most ERBB2 overexpression (IHC 3+) cases (80.0%) had ERBB2 amplification and did not have other RTK amplification or oncogene mutations. However, one-fourth of MET overexpression cases (25.0%) had ERBB2 alterations. EGFR and FGFR2 overexpression cases had ERBB2 alterations or other gene alterations such as KRAS or PIK3CA. On the other hand, most of the four RTK amplification cases (88.2%) were mutually exclusive with each amplification. However, RTK amplification did not simply correlate with protein overexpression, whereas cases with RTK high-level amplification had protein overexpression and rarely showed other co-existing gene alterations.

CONCLUSION

AGC involves a complicated arrangement of protein expression and gene alterations. Comprehensive analyses of NGS and IHC will be necessary to design the optimal therapy for treating the appropriate population of patients in future clinical trials.

Bone enhancing effect of titanium-binding proteins isolated from bovine bone and implanted into rat calvaria with titanium scaffold

Based on our previous finding that a chromatography with titanium beads selectively binds phosphoproteins, including caseins, phosvitin and dentin phosphoproteins, we investigated whether bone phosphoproteins also bind to titanium. Bovine bone matrix proteins were extracted with 2 M urea/PBS after demineralization. The 2 M urea extract was directly applied to the titanium chromatography column as reported. The chromatogram showed an initial large peak at breakthrough position (non-binding fraction) and a smaller second peak eluted later (titanium-binding fraction). Both peaks were analyzed by SDS polyacrylamide gel electrophoresis. Stains-all staining which preferentially identifies phospho-proteins revealed that the first peak contained no positively stained band, while the second peak showed 4 or 5 distinctive bands indicative of bone phosphoproteins. To investigate the biological functions of the titanium-binding bone proteins (TiBP), we implanted them into calvaria of rats, combined with titanium web (TW), a highly porous titanium scaffold of thin titanium-fibers. Bone TiBP induced significantly enhanced bone formation, and new bone appeared connected directly to titanium fibers, accompanied by active blood vessel formations. Control TW alone did not induce bone formation within the titanium framework. These results demonstrate that the bone titanium-binding proteins include phosphoproteins which enhance bone formation when implanted into bone with titanium.

Interaction between titanium and phosphoproteins revealed by chromatography column packed with titanium beads

The biochemical mechanism behind the strong binding between titanium and living bone has not been fully elucidated, in spite of worldwide clinical application of this phenomenon. We hypothesized that one of the core mechanisms may reside in the interaction between certain proteins in the host tissues and the implanted titanium. To verify the interaction between titanium and proteins, we chose the technique of chromatography in that titanium spherical beads (45 μm) were packed into a column to obtain a bed volume of 16×50 mm, which was eluted with phosphate buffered saline (PBS) and a straight gradient system made by using PBS and 25 mM NaOH. Fetal calf serum, albumin, lysozyme, casein, phosvitin and dentin phosphoprotein (phosphophoryn) were applied to the column. Most part of albumin and lysozyme eluted with the breakthrough peak, indicating practically no affinity to titanium. Fetal bovine serum also eluted mostly as the breakthrough peak, but distinct retained peak was observed. On the other hand, α-casein, phosvitin and phosphophoryn exhibited a distinct retained peak separated from the breakthrough peak. We proposed that phosphate groups (phosphoserines) in the major phosphoproteins, α-casein, phosvitin and phosphophoryn may be involved in the binding of these proteins with titanium.

Three-dimensional geometry of honeycomb collagen promotes higher beating rate of myocardial cells in culture

Myocardial cells were isolated from newborn rats, cultured on a novel three-dimensional (3-D) honeycomb collagen scaffold (HC) and their morphology and beating rates compared with ones on conventional plastic dishes. On the first day, the cells attached to HC had already started beating. As time went on, the rate of beating increased as the pores of HC gradually filled with the cells, which integrated to form the cell-matrix complex. At day 8, beating reached the highest frequency of 162 beats per minute, which was twice that of the control cells on plastic dishes. It was concluded that 3-D geometry of the HC is conducive to functional growth of the myocardial tissues, and will potentially be useful for tissue engineering of myocardial regeneration.

The effect of hydroxyapatite-coated titanium fiber web on human osteoblast functional activity

PURPOSE

The aim of this study was to evaluate human osteoblast activity on thin hydroxyapatite (HA)-coated three-dimensional scaffolds made of titanium fiber web.

MATERIALS AND METHODS

A thin HA film was coated on a titanium fiber web by the molecular precursor method. Human osteoblasts were disseminated onto the uncoated and HA-coated titanium fiber web, and osteoblast activity was observed at days 3, 7, 14, and 21 of culture.

RESULTS

Proliferation activities of osteoblasts were significantly higher in the uncoated titanium fiber web. Osteoblasts in the uncoated titanium fiber web showed a typical expression pattern, but those in the HA-coated titanium fiber web showed rapid osteocalcin expression and calcification at an early stage of culture. Moreover, osteocalcin expression per osteoblast was significantly higher in the HA-coated group.

CONCLUSION

These results suggest that HA coating with the molecular precursor method accelerated osteoblast functional activity.

Effect of the addition of bevacizumab to first-line FOLFOX on efficacy, including response rate, progression-free survival, and overall survival, in patients with metastatic colorectal cancer

588

Background: Bevacizumab (BV) is a recombinant, humanized monoclonal antibody against vascular endothelial growth factor. Used in combination with chemotherapy, BV has been shown to improve survival in both first- and second-line treatment for metastatic colorectal cancer (mCRC). However, it was reported that addition of BV to FOLFOX conferred only little survival benefit (Saltz et al. JCO2008). The aim of this study was to assess the efficacy of addition of BV to FOLFOX in first-line treatment for patients with mCRC.

Methods: Bevacizumab was approved for mCRC in July 2007 in Japan. This study was conducted at a single institution and comprised 217 consecutive patients receiving first-line treatment for mCRC between 2005 and 2009. The primary objective was to compare survival benefit in patients treated with FOLFOX4 (FF) between 2005 and 2007 with that in patients receiving FOLFOX4+BV 5 mg/kg (FF+BV) between 2007 and 2009.

Results: Total number of patients in the FF and FF+BV groups was 132 and 85, respectively. Characteristics of patients were as follows (FF vs. FF+B): median age, 62 yrs (range 28-76 yrs) vs. 60 yrs (range16-74 yrs); ECOG PS0, 98.8% vs. 81.8%; and median follow-up time, 20.8 months vs. 24.4 months. Median progression-free survival (PFS) in the FF and FF+BV groups was 10 months (95% CI, 8.7-11.3) and 17 months (95% CI, 10.2-14.1), while median overall survival (OS) was 21 months (95% CI, 17.9-24.1) and not reached, respectively. Response rate was 46% (95% CI, 37- 54) in FF, and 62% (95% CI, 51-73) in FF+BV. Addition of BV to FOLFOX4 significantly improved PFS (p=0.002) and OS (p<0.001).

Conclusions: The additive effect of BV for first-line FOLFOX was reconfirmed. These data indicate potential survival benefits from the addition of BV to FOLFOX in first-line treatment of mCRC. In addition, PFS may be a sensitive indicator of outcome prior to post-treatment.

No significant financial relationships to disclose.

Use of circulating endothelial cells to predict response to FOLFOX4 plus bevacizumab in metastatic colorectal cancer

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Background: The purpose of this study was to identify CEC threshold proposal for determining response to FOLFOX4 plus bevacizumab in metastatic colorectal cancer (mCRC).

Methods: All patients were enrolled using institutional review board-approved protocols at the Cancer Institute Hospital and provided informed consent. From July 2007 to June 2008, 33 patients treated with FOLFOX4 plus bevacizumab were enrolled in a prospective study. From January 2007 to June 2007, before bevacizumab was approved by the government in Japan, 31 patients treated with FOLFOX4 as a control were enrolled. The study population consisted of patients aged 18 years or older with histologically proven mCRC. Other inclusion criteria were Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, adequate organ function. CECs of whole blood at the baseline, day 4, 2 weeks after initiation of chemotherapy were isolated and counted using immunomagnetics.

Results: There was no correlation between CEC levels and the outcome in the FOLFOX4. In the FOLFOX4 plus bevacizumab, CEC levels at the baseline were significantly associated with the outcome. Patients with 65 or more CECs at the baseline had shorter median PFS (9.2 months), than the median PFS of fewer than 65 CECs at the baseline (18.9 months) in the FOLFOX4 plus bevacizumab (p = 0.003). Patients with 65 or more CECs at the baseline had shorter median OS (23.3 months), than the median OS of fewer than 65 CEC s at the baseline in the FOLFOX4 plus bevacizumab (p = 0.027). In the univariate analysis, lung metastasis, lymph node metastasis, and CEC levels at the baseline predicted PFS. In the univariate Cox regression analyses, peritoneal metastasis, CEC levels at the baseline were associated with OS. In order to evaluate the independent predictive effect of FOLFOX4 plus bevacizumab, multivariate Cox regression analysis was carried out. CEC levels at the baseline were the strongest predictor.

Conclusions: A threshold of lower than 65 CEC/4mL at the baseline was a significant predictor of the outcome for colorectal cancer patients treated with FOLFOX4 plus bevacizumab.

No significant financial relationships to disclose.

Coagulo-fibrinolytic activity as a predictor of efficacy in bevacizumab-combined chemotherapy in metastatic colorectal cancer patients

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Background: The combination of bevacizumab (BV) and chemotherapy in the first-line and second-line treatment of metastatic colorectal cancer (mCRC) has been shown to improve survival. Bevacizumab is a recombinant, humanized monoclonal antibody against vascular endothelial growth factor. However, the relationship between coagulo-fibrinolytic activity factors and treatment efficacy remains to be clarified. The aim of this study was to determine potential coagulo-fibrinolytic activity markers impacting survival.

Methods: Among 119 consecutive patients included in the study, 85 received first-line FOLFOX4 plus BV 5 mg/kg and 34 received second-line FOLFIRI plus BV 5 mg/kg until progression of disease or unmanageable toxicity occurred. Coagulo-fibrinolytic activity factors, including D-dimer, thrombin antithrombin complex (TAT) and carbohydrate antigen 125 (CA125) encoded by the MUC16 mucin gene were evaluated as candidate predictors of outcome.

Results: In first-line treatment, overall response, median progression-free survival (PFS) and two-year survival rate were 61.9%, 518 days and 67.3%, respectively. In second-line treatment, overall response, median PFS and median overall survival (OS) were 23.5%, 248 days and 651 days, respectively. The outcomes of the univariate analysis were as follows: normal D-dimer and CA125 levels at baseline were associated with better PFS and OS in first-line treatment; normal TAT and CA125 levels at baseline were associated with better PFS and OS in second-line treatment. According to the results of the multivariate analysis, normal D-dimer level was associated with longer PFS in first-line treatment, and only CA125 level at baseline was an independent predictor of both PFS and OS in second-line treatment.

Conclusions: The results suggest that coagulo-fibrinolytic activity factors such as TAT, D-dimer or CA125 may be useful predictors of outcome in mCRC patients receiving BV in combination with chemotherapy.

No significant financial relationships to disclose.

Honeycomb form β-tricalcium phosphate induces osteogenesis by geometrical property with BMSC

To establish an effective method for bone augmentation, we introduced a new honeycomb-like β-tricalcium phosphate (H-β-TCP) with BMP-2 as a scaffold, whose unique geometrical properties induce osteoblastic differentiation of autologous bone marrow mesenchymal stem cells (BMSCs). A total of six beagle dogs from 6 to 7 years old were used for this study. BMSCs were cultured with autologous serum and BMP-2 on H-β-TCP. Differentiation to osteoblasts was demonstrated in vitro and exo vivo. Scanning electron microscopy revealed formation and calcification of a matrix-like structure within the H-β-TCP tunnels in BMSC culture. Moreover, treatment of BMP-2 promoted osteoblastic differentiation of BMSCs in H-β-TCP in a diffusion chamber. These results indicated that H-β-TCP may be a useful tool for construction of functional artificial bone.

In vivo internal diffusion of several inorganic microparticles through oral administration

We observed the internal diffusion behavior of inorganic micro/nano particles through oral administration. By oral exposure, the fed particles were absorbed through the digestive system then reached some organs after internal diffusion in the body. For example, TiO2 particles fed to mice were detected in the lung, liver, and spleen after 10 days of feeding. Whereas, the absorption efficiency was extremely low compared with intravenous injection. In a comparison of the simple amount of administration, oral exposure required 102 times or more amount by intravenous injection for detection by an X-ray scanning analytical microscope. During dental treatment, micro/nano particles from tooth or dental materials would generate in the oral cavity, and some of the particles had a possibility to be swallowed, absorbed through the digestive system, and then diffuse into the body. However, our results suggest that biocompatible microparticles that are naturally taken orally affect animals only rarely because of the low absorption efficiency.