Patient-derived organoids (PDOs) have recently emerged as robust preclinical models; however, their potential to predict clinical outcomes in patients has remained unclear. We report on a living biobank of PDOs from metastatic, heavily pretreated colorectal and gastroesophageal cancer patients recruited in phase 1/2 clinical trials. Phenotypic and genotypic profiling of PDOs showed a high degree of similarity to the original patient tumors. Molecular profiling of tumor organoids was matched to drug-screening results, suggesting that PDOs could complement existing approaches in defining cancer vulnerabilities and improving treatment responses. We compared responses to anticancer agents ex vivo in organoids and PDO-based orthotopic mouse tumor xenograft models with the responses of the patients in clinical trials. Our data suggest that PDOs can recapitulate patient responses in the clinic and could be implemented in personalized medicine programs.

SummaryResearchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras incolorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer. © 2001 Cancer Research Campaign http://www.bjcancer.comIt is widely accepted that mutations in the Kirsten ras (Ki-ras) gene in patients with colorectal cancer develop early in the progression from adenoma to carcinoma. Our first collaborative study including 2721 patients, clarified that Ki-ras mutations are not only 692

Phosphatidylinositol-3-kinase (PI3K) is an important target in cancer due to the deregulation of the PI3K/ Akt signaling pathway in a wide variety of tumors. A series of thieno[3,2-d]pyrimidine derivatives were prepared and evaluated as inhibitors of PI3 kinase p110alpha. The synthesis, biological activity, and further profiling of these compounds are described. This work resulted in the discovery of 17, GDC-0941, which is a potent, selective, orally bioavailable inhibitor of PI3K and is currently being evaluated in human clinical trials for the treatment of cancer.

Background: Kirsten ras (Ki-ras) gene mutations occur early in the progression of colorectal adenoma to carcinoma. The aim of this collaborative study was to clarify the association between Ki-ras mutations, patient outcome, and tumor characteristics by use of data from colorectal cancer patients worldwide. Methods: Investigators who had published data on Ki-ras and colorectal cancer were invited to complete a questionnaire for each patient entered into a database. Twosided statistical tests were used to analyze data. Results: Patients (n = 2721) were recruited from 22 groups in 13 countries. Mutations of Ki-ras codon 12 (wild type = GGT = glycine) or codon 13 (wild type = GGC = glycine) were detected in 37.7% of the tumors; 80.8% (584 of 723) of all the specified mutations occurred in codon 12, and 78.1% (565 of 723) of all the specified mutations were at the second base of either codon. Mutations were not associated with sex, age, tumor site, or Dukes' stage. Mutation rates seen in patients with sporadic tumors were comparable to those observed in patients with a predisposing cause for their cancer. Poorly differentiated tumors were less frequently mutated (P = .002). Multivariate analysis suggested that the presence of a mutation increased risk of recurrence (P<.001) and death (P = .004). In particular, any mutation of guanine (G) to thymine (T) but not to adenine (A) or to cytosine (C) increased the risk of recurrence (P = .006) and death (P<.001). When individual, specific mutations were evaluated, only valine codon 12 was found to convey an independent, increased risk of recurrence (P = .007) and death (P = .004). Conclusions: Ki-ras mutations are associated with increased risk of relapse and death, but some mutations are more aggressive than others. [J Natl Cancer Inst 1998;90:675-84]

Client protein activation by Hsp90 involves a plethora of cochaperones whose roles are poorly defined. A ubiquitous family of stress-regulated proteins have been identified (Aha1, activator of Hsp90 ATPase) that bind directly to Hsp90 and are required for the in vivo Hsp90-dependent activation of clients such as v-Src, implicating them as cochaperones of the Hsp90 system. In vitro, Aha1 and its shorter homolog, Hch1, stimulate the inherent ATPase activity of yeast and human Hsp90. The identification of these Hsp90 cochaperone activators adds to the complex roles of cochaperones in regulating the ATPase-coupled conformational changes of the Hsp90 chaperone cycle.

Heat-shock protein 70 (HSP70) isoforms contribute to tumorigenesis through their well-documented antiapoptotic activity and via their role as cochaperones for the HSP90 molecular chaperone. HSP70 expression is induced following treatment with HSP90 inhibitors, which may attenuate the cell death effects of this class of inhibitor. Here we show that silencing either heat-shock cognate 70 (HSC70) or HSP72 expression in human cancer cell lines has no effect on HSP90 activity or cell proliferation. However, simultaneously reducing the expression of both of these isoforms induces proteasome-dependent degradation of HSP90 client proteins, G1 cell-cycle arrest, and extensive tumor-specific apoptosis. Importantly, simultaneous silencing of HSP70 isoforms in nontumorigenic cell lines does not result in comparable growth arrest or induction of apoptosis, indicating a potential therapeutic window.

The discovery and development of small molecule cancer drugs has been revolutionised over the last decade. Most notably, we have moved from a one-size-fits-all approach that emphasized cytotoxic chemotherapy to a personalised medicine strategy that focuses on the discovery and development of molecularly targeted drugs that exploit the particular genetic addictions, dependencies and vulnerabilities of cancer cells. These exploitable characteristics are increasingly being revealed by our expanding understanding of the abnormal biology and genetics of cancer cells, accelerated by cancer genome sequencing and other high-throughput genome-wide campaigns, including functional screens using RNA interference. In this review we provide an overview of contemporary approaches to the discovery of small molecule cancer drugs, highlighting successes, current challenges and future opportunities. We focus in particular on four key steps: Target validation and selection; chemical hit and lead generation; lead optimization to identify a clinical drug candidate; and finally hypothesis-driven, biomarker-led clinical trials. Although all of these steps are critical, we view target validation and selection and the conduct of biology-directed clinical trials as especially important areas upon which to focus to speed progress from gene to drug and to reduce the unacceptably high attrition rate during clinical development. Other challenges include expanding the envelope of druggability for less tractable targets, understanding and overcoming drug resistance, and designing intelligent and effective drug combinations. We discuss not only scientific and technical challenges, but also the assessment and mitigation of risks as well as organizational, cultural and funding problems for cancer drug discovery and development, together with solutions to overcome the ‘Valley of Death’ between basic research and approved medicines. We envisage a future in which addressing these challenges will enhance our rapid progress towards truly personalised medicine for cancer patients.

Extensive evidence implicates activation of the lipid phosphatidylinositide 3-kinase (PI3K) pathway in the genesis and progression of various human cancers. PI3K inhibitors thus have considerable potential as molecular cancer therapeutics. Here, we detail the pharmacologic properties of a prototype of a new series of inhibitors of class I PI3K. PI103 is a potent inhibitor with low IC 50 values against recombinant PI3K isoforms p110A (2 nmol/L), p110B (3 nmol/L), p110D (3 nmol/L), and p110; (15 nmol/L). PI103 also inhibited TORC1 by 83.9% at 0.5 Mmol/L and exhibited an IC 50 of 14 nmol/L against DNA-PK. A high degree of selectivity for the PI3K family was shown by the lack of activity of PI103 in a panel of 70 protein kinases. PI103 potently inhibited proliferation and invasion of a wide variety of human cancer cells in vitro and showed biomarker modulation consistent with inhibition of PI3K signaling. PI103 was extensively metabolized, but distributed rapidly to tissues and tumors. This resulted in tumor growth delay in eight different human cancer xenograft models with various PI3K pathway abnormalities. Decreased phosphorylation of AKT was observed in U87MG gliomas, consistent with drug levels achieved. We also showed inhibition of invasion in orthotopic breast and ovarian cancer xenograft models and obtained evidence that PI103 has antiangiogenic potential. Despite its rapid in vivo metabolism, PI103 is a valuable tool compound for exploring the biological function of class I PI3K and importantly represents a lead for further optimization of this novel class of targeted molecular cancer therapeutic. [Cancer Res 2007;67(12):5840-50]