Jean-Pierre Wery

A subset of gastric cancers with EGFR amplification and overexpression respond to cetuximab therapy

A preclinical trial identified 4 of 20 (20%) gastric cancer (GC) patient-derived xenografts responded to cetuximab. Genome-wide profiling and additional investigations revealed that high EGFR mRNA expression and immunohistochemistry score (3+) are associated with tumor growth inhibition. Furthermore, EGFR amplification were observed in 2/4 (50%) responders with average copy number 5.8 and >15 respectively. Our data suggest that a GC subtype with EGFR amplification and overexpression benefit from cetuximab treatment.

Overcoming erlotinib resistance with tailored treatment regimen in patient‐derived xenografts from naïve Asian NSCLC patients

Overall benefits of EGFR‐TKIs are limited because these treatments are largely only for adenocarcinoma (ADC) with EGFR activating mutation. The treatments also usually lead to development of resistances. We have established a panel of patient‐derived xenografts (PDXs) from treatment naïve Asian NSCLC patients, including those containing “classic” EGFR activating mutations. Some of these EGFR‐mutated PDXs do not respond to erlotinib: LU1868 containing L858R/T790M mutations, and LU0858 having L858R mutation as well as c‐MET gene amplification, both squamous cell carcinoma (SCC). Treatment of LU0858 with crizotinib, a small molecule inhibitor for ALK and c‐MET, inhibited tumor growth and c‐MET activity. Combination of erlotinib and crizotinib caused complete response, indicating the activation of both EGFR and c‐MET promote its growth/survival. LU2503 and LU1901, both with wild‐type EGFR and c‐MET gene amplification, showed complete response to crizotinib alone, suggesting that c‐MET gene amplification, not EGFR signaling, is the main oncogenic driver. Interestingly, LU1868 with the EGFR L858R/T790M, but without c‐met amplification, had a complete response to cetuximab. Our data offer novel practical approaches to overcome the two most common resistances to EGFR‐TKIs seen in the clinic using marketed target therapies.

Molecular Pathology of Patient Tumors, Patient-Derived Xenografts, and Cancer Cell Lines.

The Cancer Genome Atlas (TCGA) project has generated abundant genomic data for human cancers of various histopathology types and enabled exploring cancer molecular pathology per big data approach. We developed a new algorithm based on most differentially expressed genes (DEG) per pairwise comparisons to calculate correlation coefficients to be used to quantify similarity within and between cancer types. We systematically compared TCGA cancers, demonstrating high correlation within types and low correlation between types, thus establishing molecular specificity of cancer types and an alternative diagnostic method largely equivalent to histopathology. Different coefficients for different cancers in study may reveal that the degree of the within-type homogeneity varies by cancer types. We also performed the same calculation using the TCGA-derived DEGs on patient-derived xenografts (PDX) of different histopathology types corresponding to the TCGA types, as well as on cancer cell lines. We, for the first time, demonstrated highly similar patterns for within- and between-type correlation between PDXs and patient samples in a systematic study, confirming the high relevance of PDXs as surrogate experimental models for human diseases. In contrast, cancer cell lines have drastically reduced expression similarity to both PDXs and patient samples. The studies also revealed high similarity between some types, for example, LUSC and HNSCC, but low similarity between certain subtypes, for example, LUAD and LUSC. Our newly developed algorithm seems to be a practical diagnostic method to classify and reclassify a disease, either human or xenograft, with better accuracy than traditional histopathology. Cancer Res; 76(16); 4619-26. ©2016 AACR.

A set of defined oncogenic mutation alleles seems to better predict the response to cetuximab in CRC patient-derived xenograft than KRAS 12/13 mutations

Cetuximab is a standard of care for treating EGFR-expressing metastatic colorectal carcinoma (mCRC) exclusive of those with KRAS mutations at codons 12/13. However, retrospective analysis has recently suggested that KRAS-G13D patients can still benefit, while only a fraction of KRAS wild-type patients can benefit, from the treatment. We set out to test this contradicting issue experimentally in an independent cohort of patient derived xenograft (PDX) diseases. We conducted a mouse clinical trial (MCT) enrolling a random cohort of 27 transcriptome sequenced CRC-PDXs to evaluate cetuximab activity. The treatment responses were analyzed against the KRAS 12/13 mutation alleles, as well as several other well-known oncogenic alleles. If the response is defined by >80% tumor growth inhibition, 8/27 PDXs (∼30%) are responders versus 19/27 non-/partial responders (∼70%). We found that indeed there are no significantly fewer KRAS-12/13-allele responders (4/8 or 50%) than non-/partial responders (7/19, or 37%). In particular, there are actually no fewer G13D responders (4/8, or 50%) than in non-/partial responders (2/19 or 10.5%) statistically. Furthermore, majority of the non-/partial responders tend to have certain activating oncogenic alleles (one or more of the following common ones: K/N-RAS-G12V/D, -A146T, -Q61H/R, BRAF-V600E, AKT1-L52R and PIK3CA-E545G/K). Our data on an independent cohort support the recent clinical observation, but against the current practiced patient stratification in the cetuximab CRC treatment. Meanwhile, our data seem to suggest that a set of the six-oncogenic alleles may be of better predictive value than the current practiced stratification, justifying a new prospective clinical investigation on an independent cohort for confirmation.

AC220 and AraC cause differential inhibitory dynamics in patient-derived M5-AML with FLT3-ITD and, thus, ultimately distinct therapeutic outcomes

Engrafting the bone marrow cells of a patient with M5 acute myeloid leukemia into immunocompromised mice (AM7577) resulted in serially transferrable stable AML and eventual mortality. The disease starts in the bone marrow and then expands to peripheral areas, which is typical of M5 leukemogenesis, where high leukemic burden in blood is coincident with symptoms/mortality. The leukemic cells in the mice had myeloid morphology, phenotypes, and genotypes (including the internal tandem duplication of FMS-like tyrosine kinase receptor 3 gene [FLT3-ITD]) similar to those of the original patient. Autocrine mechanisms of human granulocyte-macrophage colony-stimulating factor/interleukin-3 likely support AM7577 growth in mice. Treatment with FLT3 TKI (AC220) caused complete remission in peripheral blood, spleen, and bone, along with relief of symptoms and extended life, hinting that FLT3-ITD may be a key leukemogenic driver maintaining the disease. Interestingly, withdrawal of AC220 (high dose) did not result in relapse of disease, suggesting cure. These results, however, are in contrast to cytarabine (AraC) induction treatment: First, although AraC significantly suppresses the diseases in blood, and to a lesser degree in bone marrow and spleen, the suppression is temporary and does not prevent eventual onset of disease/death. Second, the withdrawal of AraC always resulted in rapid relapse in peripheral blood and eventually death. Our observation in this patient-derived model may provide useful information for clinical applications of the two drugs.

Cetuximab response in CRC patient-derived xenografts seems predicted by an expression based RAS pathway signature

Cetuximab is an approved treatment for metastatic colorectal carcinoma (mCRC) with codon 12/13-KRAS mutations, recently questioned for its validity, and alternative mutation-based biomarkers were proposed. We set out to investigate whether an expression signature can also predict response by utilizing a cetuximab mouse clinical trial (MCT) dataset on a cohort of 25 randomly selected EGFR+ CRC patient-derived xenografts (PDXs). While we found that the expression of EGFR and its ligands are not predictive of the cetuximab response, we tested a published RAS pathway signature, a 147-gene expression signature proposed to describe RAS pathway activity, against this MCT dataset. Interestingly, our study showed that the observed cetuximab activity has a strong correlation with the RAS pathway signature score, which was also demonstrated to have a certain degree of correlation with a historic clinical dataset. Altogether, the independent validations in unrelated datasets from independent cohort of CRCs strongly suggest that RAS pathway signature may be a relevant expression signature predictive of CRC response to cetuximab. Our data seem to suggest that an mRNA expressing signature may also be developed as a predictive biomarker for drug response, similarly to genetic mutations.

Abstract 3581: Rapid conversion to resistance, of a colon PDX with ret-fusion, by ponatinib treatment could potentially be attributed to the introduction of the gate keeper mutation V804M

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA RET encodes a receptor tyrosine kinase (RTK) involved in cellular mechanisms of proliferation, migration and differentiation. RET fusions with different genes at 10q11.2 result in constitutively activation and drive tumor development in various cancers: 10-20% of sporadic papillary thyroid cancer1, spitzoid neoplasms, CMML and 1% of lung adenocarcinomas2,3. RET fusions have been suggested to be important therapeutic targets. Ponatinib, a multi-kinase inhibitor, was approved for the treatment of Ph+ chronic myeloid leukemia (CML) and acute lymphoblast leukemia (ALL), including CML with T315I/imatinib-resistance. Ponatinib has recently been found to potently inhibit the common NSCLC fusion variant, KIF5B-RET at clinically-achievable concentrations. We have established large collection of colorectal patient derived xenografts (PDXs)4,5. Two of the poorly differentiated adenocarcinoma, CR1520 and CR2518, contain two different chromosome 10 in-frame RET-fusions, CCDC6-RET (CR2518) and NCOA4-RET (CR1520), as revealed by RNAseq and Sanger Sequencing6. Both models have also demonstrated over-expressing ret gene at mRNA levels. More importantly, they both responded Ponatinib significantly along with dephosphorylation of RET and downstream AKT, confirming these two types of Ret fusions as oncogenic drivers in these two models6. In addition, we also observed that Ponatinib treatment also rapidly drives CR2518 into its resistance (The resistant derivative is called CR2545). To investigate the underlying mechanism of the resistance, we performed RNAseq analysis of CR2545, which revealed retaining of the ret-fusion, but also the introduction of a previously described gate-keeper mutation, V804M, at ret kinase domain. V804M, a mutation frequently found in familial medullary thyroid carcinoma (FMTC), introduces bulky amino acid at position 804 and found to resistant to vandetanib. This may contribute to the resistance. However, this notion apparently contradicts to the previous observation/claim that V804M is sensitive to Ponatinib7, and ponatinib should be used to treat RET-V804M/L cancers. It is possible that the described V804M containing vandetanib resistant cells are sensitive to ponatinib, but via a non-RET mechanism for the multi-kinase inhibition nature of ponatinib; or in our case, there are other non-RET Ponatinib resistant mechanisms been introduced in CR2545 where RET is no longer the key oncogenic driver. We are currently testing other RET inhibitors and also assessing pharmacodanamic (PD) parameters to further investigate RET resistant mechanism. The further findings from the ongoing studies will be presented at the meeting. Citation Format: Mengmeng Yang, Jie Cai, Sheng Guo, Jean-Pierre Wery, Henry Qixiang Li. Rapid conversion to resistance, of a colon PDX with ret-fusion, by ponatinib treatment could potentially be attributed to the introduction of the gate keeper mutation V804M. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3581. doi:10.1158/1538-7445.AM2015-3581

Abstract 1611: Hepatocellular carcinoma xenograft models and biomarkers are powerful tools for the evaluation of the new drugs targeting HCC

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Hepatocellular Carcinoma (HCC) is a major health problem, as the fifth most common cancer and the third most common cause of cancer death worldwide. Many pharmaceutical companies lead the effort to design new medicines on this cancer type. The overwhelming need to improve preclinical models of HCC requires robust models that closely mimic the disease population and therefore have the potential to better predict clinical outcome with novel therapies. Here we successfully validated subcutaneous and orthotopic xenograft models derived from HepG2, SK-HEP-1, Hep3B, PLC/PRF/5, HUH-1, HUH-7 and MHCC97H cell lines and also directly from HCC patient tumors (HuPrime®). Four HCC serum markers (AFP, α-fetoprotein; AFP-L3; DCP, Des-gamma-Carboxyprothrombin; GP73, Golgi Protein-73) have been used or will be potentially used clinically in detection of this disease. AFP is the most widely used biomarker in HCC, somehow it is not always correlated well with the liver cancer progress, even it gives false result, and some liver lesion or liver cirrhosis can also produce high level of AFP; while GP73 is reported a promising alternative as HCC serum marker. AFP and GP73 were tested at both mRNA level and protein level. They were also compared in the sensitivity and correlation with the tumor burden using the blood samples from the orthotopic xenograft models. Our results demonstrated that biomarkers released by the tumor models could well monitor the tumor take rate, growth and response to treatments. Furthermore, Sorafenib, one popular anti- HCC medicine, was tested, and the serum biomarkers could be utilized for confidence in evaluating the efficacy of Sorafenib. In conclusion, the use of HCC xenograft models combined with the biomarker strategies is helpful in maximizing the value of in vivo research and designing clinical trials Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1611. doi:10.1158/1538-7445.AM2011-1611

Abstract 1658: Establishment of CD137 humanized mouse model for efficacy assessment of agonistic anti-CD137 therapeutic antibodies

CD137 belongs to the TNF receptor super family, and its activation is essential to the function of T cells and NK cells. Multiple agonistic CD137 antibodies are currently being tested in humans with advanced cancer, which expected to become an important new immuno-oncology therapeutics in clinic. It is important to establish preclinical models for efficacy assessment of investigational CD137 antibodies before entering clinic. Currently available animal models cannot meet this need. Syngeneic mouse tumor models provide a useful platform for testing surrogate immuno-oncology therapies, but cannot be used for testing human therapeutic antibodies due to the species specificity; human immunity reconstituted models, by human PBMC or hematopoietic stem cell inoculation into immune deficient mice, suffering from highly variable responses, are not robust enough to provide a reliable system for efficacy studies. Establishing target humanized models by replacing mouse therapeutic target with human counterpart while maintaining normal mouse immunity is a practical approach to evaluate human therapeutic antibodies in vivo. Using CRISPR-Cas9 gene editing, we have engineered human CD137 knock-in model expressing chimeric human/mouse CD137 composed of human extracellular and transmembrane domains (Exon 4-7), with intact mouse signal peptide and intracellular domain. FACS analysis of splenocytes derived from homozygous knock-in mice showed that CD3/CD28 stimulated T cells only express chimeric CD137 reactive to human CD137 antibodies, but not mouse CD137; Yet the expression levels of the chimeric CD137 in the knock-in mice are generally lower than endogenous mouse protein in wild-type C57BL/6 mice. At present, we are testing the efficacy of reference human CD137 agonistic antibodies by treating these homozygous knock-in mice grafted with syngeneic MC38 tumor cells. Data will be presented at the conference. Citation Format: Davy Xuesong Ouyang, Gang Chen, Zhensheng Wang, Lei Zheng, Annie Xiaoyu An, Jean-Pierre Wery, Jay Liu, Xin Dong, Henry Q. X. Li. Establishment of CD137 humanized mouse model for efficacy assessment of agonistic anti-CD137 therapeutic antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1658. doi:10.1158/1538-7445.AM2017-1658

Abstract A30: Modeling an immunotherapy of NK mechanism on a NSCLC patient derived xenograft

The recent clinical successes of immune checkpoint inhibitors have fueled the intense interest in novel immuno-oncology (I/O) therapeutics. The lack of relevant animal models remains a major hurdle in understanding the mechanism of action and evaluating the efficacy of such therapeutics. Patient derived xenograft (PDX), considered to most closely mimic patient tumors in both histo- and molecular pathology1,2, is however rarely used in I/O studies because it grow only in immune-compromised hosts. In reality, many PDXs grow well in nude mice where certain immune functions remain intact, excluding T-cells/T-cell functions. Therefore, PDX could still potentially be of practical use for studying T-cell independent I/O therapy. This study set out to evaluate a biologics for the treatment of a patient derived xenograft disease, by activating mouse natural killer (NK). NK and CD8 T cells are two major immune effector cell types that mediate cytotoxicity to tumor cells in vivo. One of the immunomodulatory agents, an anti-PD-L1 antibody-based IL-15 immunocytokine, was recently tested as a novel I/O treatment of cancer3. This molecule was engineered to be cross-species for both human and mouse PD-L1 and IL-15 that antagonize PD1/PD-L1 checkpoint-mediated immune suppression and also target the PD-L1-expressing tumor with IL-15 stimulated NK and CD8 T effector cells into local tumor sites, thus synergizing tumor-located anti-tumor immunity. In fact, our previous studies have demonstrated a greatly enhanced anti-tumor activity in the PDL-1-expressing syngeneic mouse tumor models via the mobilization of tumor infiltrating lymphocyte (TILs), over the PD-L1 antibody alone3. Since IL-15 also stimulates NKs in addition to T-cells, we reasoned that this bifunctional agent could also have potential activity against a PD-L1-expressing PDX in nude mice where NK remains functional. LU1901 is previously described NSCLC-PDX1, and was confirmed to express high level of PD-L1 by both RNAseq and flow analysis, after screening of a large panel of PDXs. We implanted LU1901 in Balb/c nude mice, and started to treat the mice by the bifunctional agent when the tumor reached to 150 mm3. Our result clearly demonstrated a significant inhibition of LU1901 growth by the bifunctional agent in nude mice, in the apparent absence of T-cells. When the treated tumors were examined at the termination, significantly infiltrate NK cells were found inside the treated tumors, as measured by both flow cytometry and immunohistochemistry (IHC). The number of infiltrating NK also statistically correlates to the amplitude of the tumor responses. Together, our data suggest that one of important mechanisms of action of this bifunctional agent relies on the tumor-targeting NK activation, and also that PDX could be a useful model suitable for in vivo efficacy analysis of T-cell independent immunotherapy. References 1. Yang, M., et al. Overcoming erlotinib resistance with tailored treatment regimen in patient-derived xenografts from naive Asian NSCLC patients. International journal of cancer. Journal international du cancer 132, E74-84 (2013). 2. Guo, S., Wubin Qian, Jie Cai, Likun Zhang, Jean-Pierre Wery, Qi-Xiang Li. Molecular pathology of patient tumors, patient derived xenografts and cancer cell lines EORTC-NCI-AACR. (2015). 3. Yan Wu, Zhaojing Zhong, Stella Martomo, Dan Lu, Zhanna Polonskaya, Xenia Luna, Haifan Zhang, Zhikai Zhang, Zhun Wang*, Leo Liu*, Jeegar Patel, James Tonra, Henry Li*, Larry Witte, Sam Waksal, Zhenping Zhu. Anti-PD-L1 antibody-based IL-15 immunocytokine has enhanced antitumor immunity. EORTC-NCI-AACR Abstract (2015). Citation Format: Henry Q. Li, Zhun Wang, Xiaoyu An, Jinping Liu, Likun Zhang, Jean-Pierre Wery, Yan Wu, James Tonra, Sam Waksal, Zhenping Zhu. Modeling an immunotherapy of NK mechanism on a NSCLC patient derived xenograft. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A30.