Adverse events of nivolumab plus ipilimumab versus nivolumab plus cabozantinib: a real-world pharmacovigilance study.

BACKGROUND: No head-to-head clinical trials have compared the differences in adverse events (AEs) between nivolumab plus ipilimumab (NIVO-IPI) and nivolumab plus cabozantinib (NIVO-CABO) in the treatment of metastatic renal cell carcinoma (mRCC). AIM: We analysed the two largest real-world databases, the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) and the World Health Organization's VigiBase, to elucidate the differences in AEs between NIVO-IPI and NIVO-CABO. METHOD: In total, 40,376 and 38,022 records were extracted from FAERS and VigiBase, and 193 AEs were analysed. The reporting odds ratios (ROR) with 95% confidence interval were calculated using a disproportionality analysis (NIVO-CABO/NIVO-IPI). RESULTS: The reported numbers of immune-related AEs, including myocarditis, colitis, and hepatitis, were significantly higher with NIVO-IPI (ROR = 0.18 for FAERS and 0.13 for VigiBase). Contrarily, the reported numbers of other AEs, including gastrointestinal disorders (ROR = 2.68 and 2.92) and skin and subcutaneous tissue disorders (ROR = 2.94 and 3.55), considered to be potentiated by the combination of NIVO and CABO, were higher with NIVO-CABO. CONCLUSION: Our findings contribute to the selection and clinical management of NIVO-IPI and NIVO-CABO, which minimizes the risk of AEs for individual patients with mRCC by considering distinctive differences in the AE profiles.

A comparison between the adverse event profiles of patients receiving palbociclib and abemaciclib: analysis of two real-world databases.

BACKGROUND: Palbociclib and abemaciclib are cyclin-dependent kinase (CDK) 4/6 inhibitors currently used to treat breast cancer. Although their therapeutic efficacies are considered comparable, differences in adverse event (AE) profiles of the two drugs remain unclear. AIM: We analysed two real-world databases, the World Health Organization's VigiBase and the Food and Drug Administration Adverse Event Reporting System (FAERS), to identify differences in AE profiles of palbociclib and abemaciclib. METHOD: Data of patients with breast cancer receiving palbociclib or abemaciclib recorded until December 2022 were extracted from the VigiBase and FAERS databases. In total, 200 types of AEs were analysed. The reporting odds ratios were calculated using a disproportionality analysis. RESULTS: Cytopenia was frequently reported in patients receiving palbociclib, whereas interstitial lung disease and diarrhoea were frequently reported in those receiving abemaciclib. Moreover, psychiatric and nervous system disorders were more common in the palbociclib group, whereas renal and urinary disorders were more common in the abemaciclib group. CONCLUSION: This study is the first to show comprehensively the disparities in the AE profiles of palbociclib and abemaciclib. The findings highlight the importance of considering these differences when selecting a suitable CDK4/6 inhibitor to ensure safe and favourable outcomes for patients with breast cancer.

Influence of vasopressin receptor antagonists on triple-whammy acute kidney injury: A VigiBase analysis.

Although diuretics play an important role in triple-whammy acute kidney injury (AKI), it is unclear whether the type of diuretic influences the risk of triple-whammy AKI. The aim of this study was to evaluate whether vasopressin receptor antagonists affect triple-whammy AKI. This cross-sectional study used disproportionality analysis of VigiBase data to assess the risk of AKI with various diuretics. Although multiple logistic regression analysis showed that aldosterone antagonists (odds ratio [OR] 2.19, 95% CI 2.01-2.37), loop diuretics (OR 4.40, 95% CI 4.07-4.76) and thiazide diuretics (OR 1.98, 95% CI 1.83-2.15) increased the risk of AKI in patients who received non-steroidal anti-inflammatory drugs (NSAIDs) and renin-angiotensin system inhibitors (RASi), vasopressin receptor antagonists did not increase the risk of AKI in those patients. Vasopressin receptor antagonists might not influence the development of triple-whammy AKI.

Proton Pump Inhibitors and Rhabdomyolysis: Analysis of Two Different Cross-Sectional Databases.

BACKGROUND: It is unclear whether use of a proton pump inhibitors (PPIs) increases the risk of rhabdomyolysis. OBJECTIVE: To clarify whether use of PPIs increases the risk of rhabdomyolysis. METHODS: This cross-sectional study analyzed data entered into the Medical Data Vision (MDV) database in Japan and into the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS). The MDV data were analyzed to evaluate the association between use of PPIs and rhabdomyolysis. Then, the FAERS data were analyzed to evaluate whether the risk of rhabdomyolysis was increased further when a statin or fibrate was used concomitantly with a PPI. In both analyses, histamine-2 receptor antagonist was set as a comparator because it is used to treat gastric disease. In the MDV analysis, Fisher's exact test and multiple logistic regression analysis were performed. In the FAERS analysis, a disproportionality analysis using Fisher's exact test and multiple logistic regression analysis were performed. RESULTS: Multiple logistic regression analysis of both databases showed a significant association between use of PPIs and an increased risk of rhabdomyolysis (odds ratio [OR] = 1.74-1.95, P ≤ 0.01). However, use of a histamine-2 receptor antagonist was not significantly associated with increased risk of rhabdomyolysis. In the sub-analysis of the FAERS data, use of a PPI did not increase the risk of rhabdomyolysis in patients receiving a statin. CONCLUSION AND RELEVANCE: The data in 2 separate databases consistently suggest that PPIs may increase the risk of rhabdomyolysis. The evidence for this association should be assessed in further drug safety studies.

Adverse Events of Axitinib plus Pembrolizumab Versus Lenvatinib plus Pembrolizumab: A Pharmacovigilance Study in Food and Drug Administration Adverse Event Reporting System.

No head-to-head postmarket surveillance study has compared the differences in adverse events (AEs) between two combination therapies, axitinib (AXI) + pembrolizumab (PEMBRO) and lenvatinib (LEN) + PEMBRO, against metastatic renal cell carcinoma. This study aims to highlight the comprehensive differences in AEs between these two therapies based on the real-world big data from the Food and Drug Administration Adverse Event Reporting System (FAERS) database. In total, 28 937 records were extracted from the FAERS database, and 139 AEs grouped into the System Organ Class according to the Medical Dictionary for Regulatory Activities were analysed. Logistic regression analyses were performed, and the reporting odds ratio with a 95% confidence interval was determined. We found that the incidences of cardiac and hepatobiliary disorders for AXI + PEMBRO, and blood and lymphatic system, metabolism and nutrition, and vascular disorders for LEN + PEMBRO, all of which were associated with serious AEs, were higher than those for LEN + PEMBRO and AXI + PEMBRO, respectively. The differences in the AEs between AXI + PEMBRO and LEN + PEMBRO were not derived merely from those between AXI and LEN monotherapies. Furthermore, remarkable AE potentiation was observed for AXI + PEMBRO. As FAERS is a spontaneous reporting system comprising partially limited information, analysing more detailed relationships between AEs and patient or treatment characteristics was challenging in this study. The present study is the first to show the overall real-world postmarketing differences in AEs between AXI + PEMBRO and LEN + PEMBRO. Our novel findings will substantially improve clinical practice; we recommend comparing patients' conditions associated with the above AEs when selecting between these two therapies. PATIENT SUMMARY: Herein, we highlight the differences in adverse events (AEs) between axitinib + pembrolizumab and lenvatinib + pembrolizumab therapies using data from the real-world Food and Drug Administration Adverse Event Reporting System database aimed at patients with metastatic renal cell carcinoma. We identified AEs that needed attention in each combination. We recommend the differences in AEs to be considered when selecting these two therapies.

Significance of UGT1A6, UGT1A9, and UGT2B7 genetic variants and their mRNA expression in the clinical outcome of renal cell carcinoma.

UDP-glucuronosyltransferase (UGT) metabolizes a number of endogenous and exogenous substrates. Renal cells express high amounts of UGT; however, the significance of UGT in patients with renal cell carcinoma (RCC) remains unknown. In this study, we profile the mRNA expression of UGT subtypes (UGT1A6, UGT1A9, and UGT2B7) and their genetic variants in the kidney tissue of 125 Japanese patients with RCC (Okayama University Hospital, Japan). In addition, we elucidate the association between the UGT variants and UGT mRNA expression levels and clinical outcomes in these patients. The three representative genetic variants, namely, UGT1A6 541A > G, UGT1A9 i399C > T, and UGT2B7-161C > T, were genotyped, and their mRNA expression levels in each tissue were determined. We found that the mRNA expression of the three UGTs (UGT1A6, UGT1A9, and UGT2B7) are significantly downregulated in RCC tissues. Moreover, in patients with RCC, the UGT2B7-161C > T variant and high UGT2B7 mRNA expression are significantly correlated with preferable cancer-specific survival (CSS) and overall survival (OS), respectively. As such, the UGT2B7-161C > T variant and UGT2B7 mRNA expression level were identified as significant independent prognostic factors of CSS and CSS/OS, respectively. Taken together, these findings indicate that UGT2B7 has a role in RCC progression and may, therefore, represent a potential prognostic biomarker for patients with RCC.

Drug repositioning of tranilast to sensitize a cancer therapy by targeting cancer-associated fibroblast.

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment that mediate resistance of cancer cells to anticancer drugs. Tranilast is an antiallergic drug that suppresses the release of cytokines from various inflammatory cells. In this study, we investigated the inhibitory effect of tranilast on the interactions between non-small cell lung cancer (NSCLC) cells and the CAFs in the tumor microenvironment. Three EGFR-mutant NSCLC cell lines, two KRAS-mutant cell lines, and three CAFs derived from NSCLC patients were used. To mimic the tumor microenvironment, the NSCLC cells were cocultured with the CAFs in vitro, and the molecular profiles and sensitivity to molecular targeted therapy were assessed. Crosstalk between NSCLC cells and CAFs induced multiple biological effects on the NSCLC cells both in vivo and in vitro, including activation of the STAT3 signaling pathway, promotion of xenograft tumor growth, induction of epithelial-mesenchymal transition (EMT), and acquisition of resistance to molecular-targeted therapy, including EGFR-mutant NSCLC cells to osimertinib and of KRAS-mutant NSCLC cells to selumetinib. Treatment with tranilast led to inhibition of IL-6 secretion from the CAFs, which, in turn, resulted in inhibition of CAF-induced phospho-STAT3 upregulation. Tranilast also inhibited CAF-induced EMT in the NSCLC cells. Finally, combined administration of tranilast with molecular-targeted therapy reversed the CAF-mediated resistance of the NSCLC cells to the molecular-targeted drugs, both in vitro and in vivo. Our results showed that combined administration of tranilast with molecular-targeted therapy is a possible new treatment strategy to overcome drug resistance caused by cancer-CAF interaction.

YES1 as a Therapeutic Target for HER2-Positive Breast Cancer after Trastuzumab and Trastuzumab-Emtansine (T-DM1) Resistance Development.

Trastuzumab-emtansine (T-DM1) is a therapeutic agent molecularly targeting human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC), and it is especially effective for MBC with resistance to trastuzumab. Although several reports have described T-DM1 resistance, few have examined the mechanism underlying T-DM1 resistance after the development of acquired resistance to trastuzumab. We previously reported that YES1, a member of the Src family, plays an important role in acquired resistance to trastuzumab in HER2-amplified breast cancer cells. We newly established a trastuzumab/T-DM1-dual-resistant cell line and analyzed the resistance mechanisms in this cell line. At first, the T-DM1 effectively inhibited the YES1-amplified trastuzumab-resistant cell line, but resistance to T-DM1 gradually developed. YES1 amplification was further enhanced after acquired resistance to T-DM1 became apparent, and the knockdown of the YES1 or the administration of the Src inhibitor dasatinib restored sensitivity to T-DM1. Our results indicate that YES1 is also strongly associated with T-DM1 resistance after the development of acquired resistance to trastuzumab, and the continuous inhibition of YES1 is important for overcoming resistance to T-DM1.

Overcoming epithelial-mesenchymal transition-mediated drug resistance with monensin-based combined therapy in non-small cell lung cancer.

BACKGROUND: The epithelial-mesenchymal transition (EMT) is a key process in tumor progression and metastasis and is also associated with drug resistance. Thus, controlling EMT status is a research of interest to conquer the malignant tumors. MATERIALS AND METHODS: A drug repositioning analysis of transcriptomic data from a public cell line database identified monensin, a widely used in veterinary medicine, as a candidate EMT inhibitor that suppresses the conversion of the EMT phenotype. Using TGF-ß-induced EMT cell line models, the effects of monensin on the EMT status and EMT-mediated drug resistance were assessed. RESULTS: TGF-ß treatment induced EMT in non-small cell lung cancer (NSCLC) cell lines and the EGFR-mutant NSCLC cell lines with TGF-ß-induced EMT acquired resistance to EGFR-tyrosine kinase inhibitor. The addition of monensin effectively suppressed the TGF-ß-induced-EMT conversion, and restored the growth inhibition and the induction of apoptosis by the EGFR-tyrosine kinase inhibitor. CONCLUSION: Our data suggested that combined therapy with monensin might be a useful strategy for preventing EMT-mediated acquired drug resistance.

Antitumor Effects of Pan-RAF Inhibitor LY3009120 Against Lung Cancer Cells Harboring Oncogenic BRAF Mutation.

BACKGROUND/AIM: The therapeutic strategy for patients with non-small-cell lung cancer (NSCLC) harboring the BRAF non-V600E mutation has not been established. LY3009120, a newly discovered pan-RAF inhibitor, has shown strong antitumor effects in cancers with various BRAF genotypes. This study investigated the antitumor effects of LY3009120 in NSCLC cells harboring the BRAF non-V600E mutation. MATERIALS AND METHODS: We examined the antitumor effects of LY3009120 by MTS assay and flow cytometry. We analyzed the expression status of proteins by western blot. The mouse xenograft models were used for the in vivo experiments. RESULTS: LY3009120 suppressed BRAF-related downstream pathway molecules and induced cleavage of poly ADP-ribose polymerase in all examined NSCLC cell lines. LY3009120 also inhibited in vivo tumor growth in NSCLC cells harboring the BRAF non-V600E mutation. CONCLUSION: LY3009120 is a potent therapeutic agent for patients with BRAF non-V600E mutant NSCLC.

YES1 activation induces acquired resistance to neratinib in HER2-amplified breast and lung cancers.

Molecular-targeted therapies directed against human epidermal growth factor receptor 2 (HER2) are evolving for various cancers. Neratinib is an irreversible pan-HER tyrosine kinase inhibitor and has been approved by the FDA as an effective drug for HER2-positive breast cancer. However, acquired resistance of various cancers to molecular-targeted drugs is an issue of clinical concern, and emergence of resistance to neratinib is also considered inevitable. In this study, we established various types of neratinib-resistant cell lines from HER2-amplified breast and lung cancer cell lines using several drug exposure conditions. We analyzed the mechanisms of emergence of the resistance in these cell lines and explored effective strategies to overcome the resistance. Our results revealed that amplification of YES1, which is a member of the SRC family, was amplified in two neratinib-resistant breast cancer cell lines and one lung cancer cell line. Knockdown of YES1 by siRNA and pharmacological inhibition of YES1 by dasatinib restored the sensitivity of the YES1-amplified cell lines to neratinib in vitro. Combined treatment with dasatinib and neratinib inhibited tumor growth in vivo. This combination also induced downregulation of signaling molecules such as HER2, AKT and MAPK. Our current results indicate that YES1 plays an important role in the emergence of resistance to HER2-targeted drugs, and that dasatinib enables such acquired resistance to neratinib to be overcome.

Acquired resistance mechanisms to afatinib in HER2-amplified gastric cancer cells.

Cancer treatment, especially that for breast and lung cancer, has entered a new era and continues to evolve, with the development of genome analysis technology and the advent of molecular targeted drugs including tyrosine kinase inhibitors. Nevertheless, acquired drug resistance to molecular targeted drugs is unavoidable, creating a clinically challenging problem. We recently reported the antitumor effect of a pan-HER inhibitor, afatinib, against human epidermal growth factor receptor 2 (HER2)-amplified gastric cancer cells. The purpose of the present study was to identify the mechanisms of acquired afatinib resistance and to investigate the treatment strategies for HER2-amplified gastric cancer cells. Two afatinib-resistant gastric cancer cell lines were established from 2 HER2-amplified cell lines, N87 and SNU216. Subsequently, we investigated the molecular profiles of resistant cells. The activation of the HER2 pathway was downregulated in N87-derived resistant cells, whereas it was upregulated in SNU216-derived resistant cells. In the N87-derived cell line, both MET and AXL were activated, and combination treatment with afatinib and cabozantinib, a multikinase inhibitor that inhibits MET and AXL, suppressed the cell growth of cells with acquired resistance both in vitro and in vivo. In the SNU216-derived cell line, YES1, which is a member of the Src family, was remarkably activated, and dasatinib, a Src inhibitor, exerted a strong antitumor effect in these cells. In conclusion, we identified MET and AXL activation in addition to YES1 activation as novel mechanisms of afatinib resistance in HER2-driven gastric cancer. Our results also indicated that treatment strategies targeting individual mechanisms of resistance are key to overcoming such resistance.

Ganetespib in Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor-resistant Non-small Cell Lung Cancer.

BACKGROUND: The 90-kDa heat-shock protein (HSP90) is a chaperone protein expressed at high levels in cancer cells and is involved in the folding or stabilization of several client proteins, including epidermal growth factor receptor (EGFR). Ganetespib is a second-generation HSP90 inhibitor with a potent antitumor effect against various cancer types. MATERIALS AND METHODS: This study examined the antitumor effect of ganetespib in EGFR-mutant non-small cell lung cancer (NSCLC) cells and experimentally established EGFR-tyrosine kinase inhibitor (TKI)-resistant cells harboring various resistance mechanisms, including EGFR T790M mutation, met proto-oncogene amplification, and epithelial-mesenchymal transition. RESULTS: Ganetespib showed a potent antitumor effect at low concentrations, suppressing EGFR-related downstream pathway molecules and inducing cleavage of poly ADP-ribose polymerase in all examined EGFR-TKI-resistant cell lines in vitro. Ganetespib also inhibited in vivo tumor growth in resistant cells harboring EGFR T790M. CONCLUSION: Ganetespib might be a promising therapeutic option for the treatment of patients with EGFR-TKI-resistant NSCLC.

Application of amplicon-based targeted sequencing with the molecular barcoding system to detect uncommon minor EGFR mutations in patients with treatment-naïve lung adenocarcinoma.

BACKGROUND: In lung cancer, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor sensitizing mutations co-existing with rare minor EGFR mutations are known as compound mutations. These minor EGFR mutations can lead to acquired resistance after EGFR tyrosine kinase inhibitor treatment, so determining the mutation status of patients is important. However, using amplicon-based targeted deep sequencing based on next-generation sequencing to characterize mutations is prone to sequencing error. We therefore assessed the benefit of incorporating molecular barcoding with high-throughput sequencing to investigate genomic heterogeneity in treatment-naïve patients who have undergone resection of their non-small cell lung cancer (NSCLC) EGFR mutations. METHODS: We performed amplicon-based targeted sequencing with the molecular barcoding system (MBS) to detect major common EGFR mutations and uncommon minor mutations at a 0.5% allele frequency in fresh-frozen lung cancer samples. RESULTS: Profiles of the common mutations of EGFR identified by MBS corresponded with the results of clinical testing in 63 (98.4%) out of 64 cases. Uncommon mutations of EGFR were detected in seven cases (10.9%). Among the three types of major EGFR mutations, patients with the G719X mutation had a significantly higher incidence of compound mutations than those with the L858R mutation or exon 19 deletion (p = 0.0052). This was validated in an independent cohort from the Cancer Genome Atlas dataset (p = 0.018). CONCLUSIONS: Our findings demonstrate the feasibility of using the MBS to establish an accurate NSCLC patient genotype. This work will help understand the molecular basis of EGFR compound mutations in NSCLC, and could aid the development of new treatment modalities.

Activation of AXL as a Preclinical Acquired Resistance Mechanism Against Osimertinib Treatment in EGFR-Mutant Non-Small Cell Lung Cancer Cells.

Osimertinib (AZD9291) has an efficacy superior to that of standard EGFR-tyrosine kinase inhibitors for the first-line treatment of patients with EGFR-mutant advanced non-small cell lung cancer (NSCLC). However, patients treated with osimertinib eventually acquire drug resistance, and novel therapeutic strategies to overcome acquired resistance are needed. In clinical or preclinical models, several mechanisms of acquired resistance to osimertinib have been elucidated. However, the acquired resistance mechanisms when osimertinib is initially used for EGFR-mutant NSCLC remain unclear. In this study, we experimentally established acquired osimertinib-resistant cell lines from EGFR-mutant NSCLC cell lines and investigated the molecular profiles of resistant cells to uncover the mechanisms of acquired resistance. Various resistance mechanisms were identified, including the acquisition of MET amplification, EMT induction, and the upregulation of AXL. Using targeted next-generation sequencing with a multigene panel, no secondary mutations were detected in our resistant cell lines. Among three MET-amplified cell lines, one cell line was sensitive to a combination of osimertinib and crizotinib. Acquired resistance cell lines derived from H1975 harboring the T790M mutation showed AXL upregulation, and the cell growth of these cell lines was suppressed by a combination of osimertinib and cabozantinib, an inhibitor of multiple tyrosine kinases including AXL, both in vitro and in vivo. Our results suggest that AXL might be a therapeutic target for overcoming acquired resistance to osimertinib. IMPLICATIONS: Upregulation of AXL is one of the mechanisms of acquired resistance to osimertinib, and combination of osimertinib and cabozantinib might be a key treatment for overcoming osimertinib resistance.

Therapeutic strategies for afatinib-resistant lung cancer harboring HER2 alterations.

Human epidermal growth factor receptor 2 (HER2) plays an important role in the pathogenesis of various cancers. HER2 alterations have been suggested to be a therapeutic target in non-small-cell lung cancer (NSCLC), just as in breast and gastric cancers. We previously reported that the pan-HER inhibitor afatinib could be a useful therapeutic agent as HER2-targeted therapy for patients with NSCLC harboring HER2 alterations. However, acquired resistance to afatinib was observed in the clinical setting, similar to the case for other HER inhibitors. Thus, elucidation of the mechanisms underlying the development of acquired drug resistance and exploring means to overcome acquired drug resistance are important issues in the treatment of NSCLC. In this study, we experimentally established afatinib-resistant cell lines from NSCLC cell lines harboring HER2 alterations, and investigated the mechanisms underlying the acquisition of drug resistance. The established cell lines showed several unique afatinib-resistance mechanisms, including MET amplification, loss of HER2 amplification and gene expression, epithelial-to-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like features. The afatinib-resistant cell lines showing MET amplification were sensitive to the combination of afatinib plus crizotinib (a MET inhibitor), both in vitro and in vivo. The resistant cell lines which showed EMT or had acquired CSC-like features remained sensitive to docetaxel, like the parental cells. These findings may provide clues to countering the resistance to afatinib in NSCLC patients with HER2 alterations.

Yes1 signaling mediates the resistance to Trastuzumab/Lap atinib in breast cancer.

BACKGROUND: Overexpression of human epidermal growth factor receptor 2 (HER2) is observed in approximately 15-23% of breast cancers and these cancers are classified as HER2-positive breast cancer. Trastuzumab is the first-line targeted therapeutic drug for HER2-positive breast cancer and has improved patient overall survival. However, acquired resistance to trastuzumab is still a critical issue in breast cancer treatment. We previously established a trastuzumab-resistant breast cancer cell line (named as BT-474-R) from a trastuzumab-sensitive HER2-amplified cell line BT-474. Lapatinib is also a molecular-targeted drug for HER2-positive breast cancer, which acquired the resistance to trastuzumab. Acquired resistance to lapatinib is also an issue to be conquered. METHODS: We established trastuzumab/lapatinib-dual resistant cell line (named as BT-474-RL2) by additionally treating BT-474-R with lapatinib. We analyzed the mechanisms of resistance to trastuzumab and lapatinib. Besides, we analyzed the effect of the detected resistance mechanism in HER2-positive breast cancer patients. RESULTS: Proto-oncogene tyrosine-protein kinase Yes1, which is one of the Src family members, was amplified, overexpressed and activated in BT-474-R and BT-474-RL2. Silencing of Yes1 by siRNA induced both BT-474-R and BT-474-RL2 to restore the sensitivity to trastuzumab and lapatinib. Pharmaceutical inhibition of Yes1 by the Src inhibitor dasatinib was also effective to restore the sensitivity to trastuzumab and lapatinib in the two resistant cell lines. Combination treatment with dasatinib and trastuzumab induced down-regulation of signaling molecules such as HER2 and Akt. Moreover, the combination treatments induced G1-phase cell-cycle arrest and apoptosis. Consistent with cell line data, high expression of Yes1 mRNA was correlated with worse prognosis in patients with HER2-positive breast cancer. CONCLUSION: Yes1 plays an important role in acquired resistance to trastuzumab and lapatinib in HER2-positive breast cancer. Our data suggest that pharmacological inhibition of Yes1 may be an effective strategy to overcome resistance to trastuzumab and lapatinib.

Differential combined effect of COX inhibitors on cell survival suppressed by sorafenib in the HepG2 cell line.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Sorafenib, a molecular-targeted drug, is a multi-target oral anti-neoplastic drug that is used as a first-line treatment for patients with advanced Human HCC. An increase in the expression of the cyclooxygenase-2 (COX-2) protein and sequential production of prostaglandin (PG) E2 were previously shown to significantly enhance carcinogenesis. Although the synergistic and/or additive effects of various COX inhibitors have been demonstrated in HCC, those of a combination of sorafenib and COX inhibitors remain unclear. The aim of the present study was to examine the antitumor effects of a combination of sorafenib and COX inhibitors on HCC HepG2 cells. Various COX inhibitors suppressed HepG2 cell survival, and exhibited a combined effect with sorafenib. However, COX-2 selectivity had little relevance. The co-administration of COX inhibitors and sorafenib increased the frequency of apoptosis. Moreover, the combination of sorafenib and diclofenac significantly increased Bax protein expression levels. The results of the present study indicate that COX inhibitors can be administered in combination with sorafenib for HCC therapy.