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Indiana University-Purdue University Indianapolis (IUPUI) / Pancreatic Ductal Adenocarcinoma (PDAC) is the third leading cause of cancerrelated deaths with a five-year survival rate of 11%. PDAC tumors are characterized by a dense desmoplastic stromal microenvironment, mediated in part through local cytokine production. PDAC tumors also elicit a systemic inflammatory response in the host; this, combined with a loss of body weight due to muscle and fat wasting, is characteristic of cachexia. Understanding the molecular mechanisms that drive malignant inflammation is critical to improve PDAC therapy and increase patient survival. Oncostatin M (OSM) belongs to the IL-6/GP130 family of cytokines, members of which have been shown to promote PDAC tumor development, inflammation, and cachexia. Much less is known of OSM. My central hypothesis was that OSM promotes pancreatic cancer and cachexia by inducing local and systemic inflammation, fibrosis, and wasting via OSM signaling through the receptor, OSM receptor (OSMR). We investigated effects of exogenous OSM administration in wildtype and IL-6 null mice without cancer. OSM induced systemic fibrosis, bone loss, local muscle wasting, and cardiac dysfunction in presence and absence of IL-6. We further defined the roles of OSM/OSMR in the pancreatic cancer microenvironment and macroenvironment. OSM activated genes involved in inflammation, fibrosis, and tumor progression in both tumor cells and fibroblasts and altered the tumor microenvironment, promoting a dense compaction of tumor cells and cancer associated fibroblasts. Loss of systemic OSM signaling altered tumor metabolism and reduced the stromal compartment without affecting tumor size. Loss of OSMR signaling in tumor cells reduced tumor size and promoted survival. However, systemic loss of OSM or OSMR in host cells did not halt effects of cachexia including muscle dysfunction, atrophy, or inflammation/anemia. Overall, OSM/OSMR signaling in the microenvironment is necessary in modulating tumor phenotype and promoting survival in PDAC but may not be necessary for pancreatic cancer cachexia. / 2024-08-02

Ductal adenocarcinomas of the pancreas are the 4th most common cause of cancer death. The 1 and 5 year survival rates for all stages combined are currently 26% and 5% respectively. Median survival is less than 6 months. Despite remarkable progress in the fields of genetics, cancer biology, and advances in surgical techniques as well as chemotherapeutics, our ability to recognize and treat patients with pancreatic cancer remains poor. GPCR signaling modules have been increasingly implicated in the genesis and progression of pancreatic cancers. Aberrant agonist production, receptor expression and dysfunctional signaling resulting from genomic instability in a background of a heterotopic tumor-stromal microenvironment, contribute to the initiation, progression, and eventual metastasis of the disease. Numerous GPCR agonists, including lysophosphatidic acid (LPA), along with their cognate receptors have been implicated in this oncogenic process. LPA, one of the simplest bioactive lipids, has been shown to be a potent stimulant of metastatic behavior in in vitro models. It also acts as a mitogen by inducing proliferation and cell survival pathways in various normal and transformed cell lines. In patients with pancreatic cancer both the receptors and ligand have been found to be overexpressed. It has been noted that pancreatic cancer cell lines expressing higher levels of the LPA receptors present with greater motility. This has led to the hypothesis that LPA contributes to the progression of pancreatic cancer through the promotion of a metastatic phenotype. However, the underlying mechanisms have not been well described. LPA receptors have been shown to couple to the Gi, Gq, or G12 family of heterotrimeric G proteins. Consequently, signals transduced through these receptors have been shown to stimulate Gαi, Gαq, and Gα12/13 dependent pathways. While earlier studies have linked Gαi to LPA induced migration, there is recent evidence to suggest that Gα13 may provide a major signaling mechanism for LPA receptors stimulating migration in diverse cell types including cancer cell lines. Given the ominous nature of pancreatic cancers it is of critical importance to understand the mechanisms that promote more malignant phenotypes and to assess the role of Gα13 in this process. The goal of this thesis therefore is to define the role of Gα13 in LPA-mediated migration of pancreatic cancer cells. To assess the oncogenic potential of LPA and the role of Gα13 in stimulating the migration of pancreatic cancer cells, a panel of pancreatic cancer cell lines was assembled and characterized with regard to their expression of the LPA receptors as well as the Gα subunits of the heterotrimeric G proteins. These cell lines were further studied through a series of proliferation, wound healing, and transwell migration assays to assess the role of LPA in the induction of proliferation and migration in pancreatic cancer cells. The results demonstrated that LPA functions as a mitogen in certain pancreatic cancer cell lines, but is a potent stimulant of cell motility and invasive migration. Interestingly, these studies indicated that this response proceeds through routes that may not involve Gαi, as a potent migratory response was observed in MDAPanc28 cells which lack expression of the Gαi subunit. This was verified through the transwell assays conducted in the presence of PTX demonstrating that migration occurs independently of PTX sensitive mechanism and thus independently of Gαi.. Using a dominant negative mutant strategy, the studies presented in this thesis establishes the role of Gα13 in mediating LPA-LPAR stimulated migration of pancreatic cancer cells. Using pancreatic cancer cell lines that stably express the competitively inhibitory dominant negative mutant of Gα13, the ability of these mutants to inhibit a LPA mediated migratory response was monitored by wound-healing as well as transwell migration assays The results of these studies indicated a substantial attenuation of the migratory response and demonstrated for the first time the critical role of Gα13in LPA induced migration in a pancreatic cancer cell line. / Molecular Biology and Genetics

PURPOSE: The anti-tumor activity of glucose analogs 2-deoxy-glucose (2-DG) and D-allose was investigated alone or in combination with p38 mitogen-activated protein kinase (MAPK) inhibitor SB202190 or platinum analogs as a strategy to pharmacologically target glycolytic tumor phenotypes. METHODS: Hypoxia inducible factor-1 alpha (HIF-1alpha) protein accumulation in pancreatic cell lines treated with SB202190 alone and in combination with glucose analogs was analyzed by Western blot. HIF-1alpha transcriptional activity was measured in MIA PaCa-2 cells stably transfected with a hypoxia response element luciferase reporter following treatment with glucose analogs alone, and in combination with SB202190. Induction of cleaved poly(ADP-ribose) polymerase (PARP) was measured by Western blot in the MIA PaCa-2 cells. In vitro anti-proliferative activity of 2-DG and D-allose alone, or in combination with oxaliplatin (pancreatic cell lines), cisplatin (ovarian cell lines), or with SB202190 were investigated using the MTT assay. RESULTS: SB202190 decreased HIF-1alpha protein accumulation and transcriptional activity. 2-DG demonstrated greater anti-proliferative activity than D-allose. Pre-treatment with SB202190 enhanced activity of both 2-DG and D-allose in MIA PaCa-2, BxPC-3, ASPC-1, and SK-OV-3 cells. The combination of D-allose and platinum agents was additive to moderately synergistic in all but the OVCAR-3 and HEY cells. SB202190 pre-treatment further enhanced activity of D-allose and 2-DG with platinum agents in most cell lines investigated. CONCLUSIONS: SB202190 induced sensitization of tumor cells to 2-DG and D-allose may be partially mediated by inhibition of HIF-1alpha activity. Combining glucose analogs and p38 MAPK inhibitors with chemotherapy may be an effective approach to target glycolytic tumor phenotypes.

Die Überlebensrate von Patienten mit duktalem Adenokarzinom des Pankreas ist sowohl in primär resektablen als auch im lokal fortgeschrittenen und metastasierten Stadium kurz. Das duktale Adenokarzinom des Pankreas breitet sich rasch aus und wird aufgrund fehlender Frühsymptome oft erst im fortgeschrittenen Stadium diagnostiziert. Gegenwärtig fehlen spezifische Tumormarker, die eine frühzeitige Diagnose erlauben würden. Aufgrund zahlreicher Mechanismen der primären und sekundären Chemoresistenz ist das Pankreaskarzinom verhältnismäßig resistent gegenüber konventioneller systemisch verabreichter Chemotherapie, antikörperbasierten sowie niedermolekularen Therapiestrategien, Enzyminhibitoren, Bestrahlung und chirurgischer Therapie. Ein vielversprechender Angriffspunkt zur zielgerichteten Therapie des Pankreaskarzinoms eröffnet die tumorspezifische Expression des GnRH-I Rezeptors. In dieser Arbeit konnte der GnRH-IRezeptor durch RT-PCR und immunhistochemisch in 32,5% der duktalen Adenokarzinome des Pankreas nachgewiesen werden. Es wurde gezeigt, dass die Behandlung mit dem Hybridwirksoff AESZ-108 (AN-152), einem zytotoxischen GnRH-Analogon in vitro und in vivo Apoptose in den GnRH-IRezeptor- positiven Pankreaskarzinomzelllinien induziert. Apoptose wurde durch den intrinsischen Signalweg über den Zusammenbruch des mitochondrialen Membranpotentials vermittelt und führte zu DNA-Fragmentierung des Nukleus wie fluoreszenzmikroskopisch gezeigt werden konnte. Das zytotoxische GnRH-Analogon AESZ-108 (AN-152) führt in vivo zu einer signifikanten Inhibition des Tumorwachstums im Vergleich zur Therapie mit dem Anthrazyklin Doxorubicin, welches zu keiner signifikanten Inhibition des Pankreaskarzinomwachstums führt. Die rezeptorvermittelte Aufnahme ermöglicht eine selektive Therapie. Nach rezeptorvermittelter Endozytose wird das an die D-Lys6-Seitenkette gebundene Doxorubicin spezifisch im Nukleus der rezeptorpositiven Karzinomzellen freigesetzt. Die Ergebnisse dieser Arbeiten zeigen, dass AESZ-108 (AN-152) ein geeigneter Ansatz zur selektiven Chemotherapie GnRH-I-Rezeptor positiver humaner duktaler Adenokazinome des Pankreas ist.

Background Pancreatic ductal adenocarcinoma (PDAC) patients have the poorest 5-year survival rates of all cancer forms. It is difficult to diagnose at early disease stages, tumour relapse after surgery is common, and current chemotherapies are ineffective. Carbohydrate antigen 19-9 (Ca 19-9), the only clinically implemented PDAC biomarker, is insufficient for diagnostic and screening purposes. PDAC tumours are characterised by a voluminous stroma that is rich in extracellular matrix (ECM) molecules such as collagens, hyaluronan (HA) and matricellular proteins. These stromal components have been suggested to promote PDAC cell migration, proliferation, evasion of apoptosis and chemotherapy resistance. Those events are mediated via interactions with adhesion receptors, such as integrins and CD44 receptors expressed on cancer cell surfaces. Micro-RNAs (miRNA) post-transcriptionally regulate gene expression in health and disease. At the time of PDAC diagnosis, miRNA levels are altered both in plasma and tumour tissue. Before PDAC diagnosis, tissue miRNA levels are altered in precursor lesions, raising the possibility that plasma miRNAs might aid in early detection. In this thesis, it is hypothesised that stromal components and miRNAs can serve as tissue or blood based biomarkers in PDAC. The aims are: (1) to characterise the expression of stromal components and their receptors in normal and cancerous tissue; (2) to find potential stroma-associated tissue and blood-based biomarkers for diagnosis and prognosis estimates; (3) to determine the cellular effects of type IV collagen (Col IV) in PDAC; (4) to determine if plasma miRNAs that are altered in manifest PDAC can be used to diagnose PDAC earlier. Methods The expression patterns of Col IV, Col IV-binding integrin subunits (α1, α2, β1), Endostatin, Osteopontin (OPN) and Tenascin C (TNC) were analysed in frozen PDAC and normal pancreatic tissue. A tissue microarray (TMA) was constructed using formalin-fixed, paraffin-embedded primary tumours and lymph node metastases. The TMA was used to study the expression levels and associations with survival of the standard CD44 receptor (CD44s), its variant isoform 6 (CD44v6), HA, OPN and Col IV. Circulating levels of HA, Col IV, Endostatin, OPN and TNC were measured in PDAC patients and healthy individuals, and compared with conventional tumour markers (Ca 19-9, CEA, Ca 125 and TPS). The functional roles of Col IV were studied in PDAC cell lines by: (1) growth on different matrices (2) blocking Col IV binding integrin subunits, (3) blocking the Col IV domains 7s, CB3 and NC1, and (4) by down regulation of PDAC cell synthesis of Col IV using siRNA transfection. Plasma miRNAs alterations were screened for in samples from patients with manifest disease, using real-time quantitative PCR (RT-qPCR). To find early miRNA alterations, levels of those miRNAs that were altered at diagnosis were measured in prediagnostic plasma samples. Results High tissue expression of both the standard CD44 receptor (CD44s) and its variant isoform CD44v6 as well as low expression of stromal OPN were associated with poor survival. In addition, high CD44s and low OPN predicted poor survival independent of established prognostic factors. Circulating Col IV, Endostatin, OPN, TNC and HA were increased in preoperative samples from PDAC patients. Preoperatively, higher levels of serum-HA and plasma-Endostatin were associated with shorter survival. Postoperatively, higher levels of Col IV, Endostatin and OPN were associated with shorter survival. On the contrary, only one of the conventional tumour markers was associated with survival (Ca 125). Col IV stimulated PDAC cell proliferation and migration and inhibited apoptosis in vitro, dependent on the collagenous domain (CB3) of Col IV and the Col IV binding integrin subunit β1. Reduced endogenous Col IV synthesis inhibited these effects, suggesting that PDAC cells synthesise Col IV to stimulate tumour-promoting events via a newly discovered autocrine loop. 15 miRNAs were altered in early stage PDAC patients and the combination of these markers outperformed Ca 19-9 in discriminating patients from healthy individuals. However, none of the miRNAs were altered in prediagnostic samples, suggesting that plasma miRNA alterations appear late in the disease course. Conclusions Up regulated stromal components in PDAC tumours are detectable in blood samples and are potential diagnostic and prognostic biomarkers in PDAC. High circulating levels of Col IV, Endostatin, OPN and HA predict poor survival, as well as high expression of CD44s and CD44v6 and low expression of OPN in tumour tissue. PDAC cells synthesise Col IV, which forms BM-like structures close to cancer cells and promote tumour progression in vitro via an autocrine loop. Several plasma-miRNAs are altered in PDAC, but are not useful for early discovery.

Avec un taux de survie à 5 ans inférieur à 5%, l'adénocarcinome pancréatique (PDAC) est l'un des cancers les plus agressifs et pour lequel les thérapies existantes sont largement insuffisantes. Ce cancer est caractérisé par un tissu fibreux dense et un stroma très développé, en constante interaction avec la tumeur, favorisant le développement d'un environnement propice à la progression tumorale. Actuellement, la gemcitabine est la seule chimiothérapie approuvée capable de prolonger légèrement la survie des patients. Une thérapie ciblée dirigée contre l'EGFR, l'erlotinib, a prouvé que le ciblage de cette famille pourrait être une stratégie intéressante dans cette pathologie mais qu'une sélection des patients était indispensable pour augmenter les réponses thérapeutiques. Deux récepteurs de cette famille, HER2 et HER3, dimérisent pour former une entité particulièrement agressive et impliquée dans la croissance tumorale des PDACs. Diverses techniques récemment développées sont utilisées pour quantifier ces dimères, afin d'étudier leur rôle, mais également pour tenter de les cibler, et empêcher leur signalisation dans différents cancers. A l'heure actuelle, le pertuzumab est le seul anticorps monoclonal dirigé contre le récepteur HER2, capable de bloquer sa dimérisation, et utilisé en clinique. Dans un premier temps, nous nous sommes intéressés au rôle de HER3 en tant que cible et marqueur pronostique de l'effet du pertuzumab sur les PDAC exprimant faiblement HER2. Puis dans une deuxième partie, nous avons étudié et comparé les effets de différents anticorps monoclonaux dirigés contre HER2 et/ou HER3, sur la prolifération tumorale de tumeurs du pancréas. L'ensemble de ces résultats a permis d'établir que le ciblage du dimère HER2/HER3 s'avère être une stratégie prometteuse pour inhiber la croissance des tumeurs du pancréas exprimant faiblement HER2, et que le récepteur HER3 pourrait être un marqueur pronostique de l'effet du pertuzumab. / With a 5-year survival lower than 5%, PDAC is one of the worst cancers in terms of mortality, and for which existing therapies are unsatisfying. This cancer is characterized by a dense fibrotic tissue and an over-developed stroma, in continual interaction with the tumor, promoting the development of an ideal environment for tumor progression.To date, gemcitabine is the only approved chemotherapy able to slightly increase patients' survival. The use of erlotinib, an EGFR targeting therapy, underlined that EGFR family targeting could be an interesting treatment strategy in this pathology, but that a better patients' selection is essential to increase therapeutic response. Two receptors of this family, HER2 and HER3, are able to dimerize to consititute an aggressive entity, involved in PDAC tumoral growth. Various recently developed techniques are used to quantify those dimers, in order to study their role, but also to target them and block their signaling in cancer cells. Pertuzumab is currently the only HER2-targeting monoclonal antibody able to block its dimerization and used in clinic. We first evaluated the role of HER3 as therapeutic target and prognostic marker of pertuzumab efficacy on HER2-low expressing PDACs. We then studied and compared therapeutic effects on pancreatic tumor proliferation of different antibodies targeting HER2 and/or HER3. Taken together, those results demonstrated that HER2/HER3 dimers targeting is a promising strategy to inhibit low-HER2 expressing pancreatic tumor growth, and that HER3 could be a pronostic marker for pertuzumab efficacy in those cancers.

Le cancer pancréatique représente la cinquième cause de décès par cancer dans les pays occidentaux. Son mauvais pronostic (survie à 5 ans inférieure à 3,5 % des cas) est dû à l’absence de facteurs de risques spécifiques interdisant une prévention efficace, et à un diagnostic tardif qui révèle un cancer agressif chez environ 90% des patients. Actuellement, le seul traitement curatif de ce cancer est la chirurgie, mais celle-ci ne peut être envisagée que dans 10 à 15 % des cas. L’adressage de molécules thérapeutiques vers l’organe, le tissu ou la cellule malade constitue aujourd’hui un défi majeur pour le traitement des maladies humaines notamment infectieuses, cancéreuses ou d’origine génétique. C’est pour ces raisons que le développement de nanotechnologies, en tant que vecteurs de médicaments, a pris un essor considérable au cours des dernières années. Dans ce contexte, le concept de squalènisation repose sur le couplage chimique entre le squalène (SQ), un lipide naturel précurseur de la synthèse du cholestérol, et des principes actifs (notamment des molécules anticancéreuses). Les bioconjugués ainsi formés sont alors capables de s’auto-assembler en solution aqueuse pour former des nanoparticules stables de diamètres compris entre 100 et 300 nm. L’exemple de référence dans ce domaine est la nanoparticule de gemcitabine-squalène (SQdFdC) qui a donné lieu à des résultats spectaculaires in vitro sur des lignées de cellules cancéreuses humaines In vivo, les nanoparticules de gemcitabine-squalène se sont avérées beaucoup plus efficaces que la gemcitabine libre sur des tumeurs solides greffées par voie sous-cutanée ainsi que sur des modèles murins de leucémies agressives métastatiques.Au vu de ces résultats encourageants, le projet de thèse a été développé autour de deux axes de recherche. (I) Dans un premier temps, les nanoparticules de gemcitabine-squalène ont été fonctionnalisées par un peptide capable de reconnaître et de cibler spécifiquement les cellules cancéreuses pancréatiques. (II) Le deuxième axe de recherche a visé l’encapsulation d’un second principe actif au sein des nanoparticules de gemcitabine-squalène afin de développer le concept de nanoparticule « multi-thérapeutique ». / Pancreatic cancer is a lethal disease with the worst prognosis among all solid tumors. In the last decades, progresses in pancreatic cancer therapy had remained exceedingly slow and disappointing offering minimal benefits in median survival which remains of less than 6 months and the maximum of 5 years in the 6% of patients. One of the major requirements for a successful cancer therapy is its ability to selectively kill cancer cells with minimal damage to healthy tissues. In this context, a great deal of attention focused on advanced nanoscale systems (i.e., nanomedicines) with the aim to overcome the limits associated to the traditional drug delivery modalities. Nanomedicines can indeed enhance drug properties by (i) offering protection from degradation, (ii) enabling controlled release and distribution and increasing bioavailability while reducing undesired side effects.In the current work we aimed to propose novel nanoscale-based strategies to optimize pancreatic cancer treatment taking into account the specific physio-pathology of this tumor. The first approach relied on the design of a targeted nanomedicine able to specifically bind receptors mainly expressed onto pancreatic cancer cells in order to selectively increase drug accumulation in these cells saving healthy ones.In a second approach, by combining two therapeutic agents in the same nanoparticle we constructed a multi-therapeutic drug delivery system capable to increase the therapeutic index of the combined therapy. In particular, taking advantages from the “squalenoylation prodrug approach”, the research activity of this Ph.D. work lead to the to design of (i) a novel peptide-functionalized squalenoyl gemcitabine nanoparticle and (ii) a tyrosine kinase inhibitor-loaded squalenoyl gemcitabine nanoparticle. Obtained nanoparticles were investigated with respect to their physico-chemical properties and in vitro antitumor activity. The efficacy of peptide-functionalized nanoparticles in impairing tumor growth was assessed in vivo on an experimental model of pancreatic cancer.

As neoplasias induzidas pela forma oncogênica da KRAS são doenças muito comuns, para as quais não existem terapias efetivas. Uma inibição direta da KRAS falhou em ensaios clínicos e esforços intensos tem sido feitos para identificar alvos de KRAS importantes para a oncogênese. Uma via promissora regulada por KRAS, que tem sido pouco explora a é a via dos microRNAs (miRNAs). Nossa meta foi identificar miRNAs regulados pela KRAS em células pulmonares e pancreáticas, que possam contribuir para o fenótipo oncogênico. Para alcançar esta meta nós usamos duas abordagens: (1) Nós investigamos o miRNA 486-5p como um alvo de KRAS em câncer de pâncreas e de pulmão. A expressão deste miRNA havia sido correlacionada positivamente com a presença de mutações em KRAS em pacientes portadores de câncer de cólon; (2) Nós usamos uma plataforma de microarranjo para identificar miRNAs diferencialmente expressos entre células humanas primárias imortalizadas pulmonares ou pancreáticas e suas linhagens isogênicas transformadas por KRAS. Na primeira abordagem, conseguimos mostrar que a expressão do miRNA 486-5p está correlacionada ao status de KRAS em células primárias pulmonares, mas não em células primárias pancreáticas. Além disso, geramos células pulmonares tanto com ganho e perda de função de KRAS e demonstramos que KRAS regula a expressão do miRNA 486-5p. Também de terminamos uma correlação negativa entre a expressão de KRAS e a expressão do alvo do miRNA 486-5p FoxO1, um supressor tumoral. Para avaliar como o miRNA 486-5p afeta as propriedades oncogênicas induzidas por KRAS, nós transfectamos oligonucleotídeos inibitórios para o miRNA 486-5p em células pulmonares positivas para mutações em KRAS. A inibição da expressão do miRNA 486-5p levou a uma redução da clonogenicidade e viabilidade celulares. Esta redução não está associada a um aumento de morte celular, mas a uma redução da proliferação celular. Interessantemente, a transfecção de oligonucleotídeos mímicos do miRNA 486-5p em células pulmonares negativas para mutações em KRAS ou em células com perda de função de KRAS por RNAi levou a um aumento da proliferação e clonogenicidade. Estes dados indicam que o miRNA 486-5p, não só é um alvo de KRAS em câncer de pulmão, mas também age como um oncomiR contribuindo para a proliferação celular induzida por KRAS. Na nossa segunda abordagem, nós identificamos 17 miRNAs com expressão aumentada e 3 com expressão diminuída em células primárias pancreáticas expressando KRAS oncogênica. Destes, 9 miRNAs foram foram também identificados por metanálise de dados de microarranjo publicados comparando amostras tumorais pancreáticas com amostras não tumorais. Apesar do experimento de microarranjo com as linhagens primárias pulmonares não ter produzido resultados estatisticamente significativos após a correção por FDR, uma tendência à expressão diferencial foi observada para vários miRNAs e nós validamos por qPCR a expressão diferencial dos miRNAs 720 e 139-3p. Em conclusão, nós conseguimos identificar miRNAs regulados pela KRAS tanto em células pulmonares, quanto pancreáticas. Um melhor entendimento das suas funções biológicas, bem como dos alvos por eles regulados nestes contextos, pode revelar novas vias para a exploração terapêutica. / KRAS-induced lung cancer is a very common disease, for which there are currently no effective therapies. Direct targeting of KRAS has failed in clinical trials and intense efforts are underway to identify KRAS targets that play a crucial role in oncogenesis. One promising KRAS-regulated pathway that has so far been overlooked is the micro RNA (miRNA) pathway. Our goal was to identify miRNAs regulated by oncogenic KRAS in lung and pancreatic cells that could contribute to the oncogenic phenotype. In order to achieve this goal we used two different approaches: (1) We investigated miRNA 486-5p as a KRAS target in lung and pancreatic cancer. The expression of this miRNA had been correlated to the presence of KRAS mutations in colon cancer patients; (2) we used a microarray platform to identify differentially expressed miRNAs between immortalized human primary pulmonary or pancreatic epithelial cell lines and their isogenic K-Ras-transformed counterparts. In our first approach, we were able to show that mi486-5p expression correlates with KRAS status in lung primary cells, but not in pancreatic primary cells. Furthermore, we generated lung cancer cells with either gain-of-function or loss-of-function of KRAS and demonstrated that KRAS regulates miRNA 486-5p in these cells. We also found, in all lung cell models analyzed, a negative correlation between expression of KRAS and expression of miR-486-5p target FoxO1, a tumor suppressor. In order to evaluate how miR-486-5p affects KRAS-induced oncogenic properties, we transfected miR-486-5p inhibitor oligonucleotides into KRAS-positive lung cancer cell lines. Inhibition of miR-486-5p expression leads to reduced clonogenic growth and viability. This reduction is not associated with increased cell death, but with decreased cell proliferation. Interestingly, transfection of miR-486-5p double-stranded RNA mimic oligonucleotides in to KRAS negative lung cancer cell lines or into cells with loss-of-function of KRAS by RNAi leads to enhanced proliferation and clonogenicity. These results indicate, not only that miR-486-5p is a KRAS target in lung cancer, but also that miR-486-5p acts as an oncomiR contributing to KRAS-induced cell proliferation. In our second approach, we identified 17 upregulated microRNAs and 3 downregulated microRNAs in the primary pancreatic cell line expressing KRAS. Of these, 9 miRNAs were also identified by a metanalysis of published microarray datasets comparing pancreatic cancer patient samples to non-cancerous pancreatic tissues. Even though our array experiment in the primary pulmonary cells did not produce statistically significant results after FDR correction, differential expression trends were seen for many miRNAs and we validated miRNAs 720 and 139-3p as differentially expressed. In conclusion we were able to identify miRNAs regulated by KRAS both in lung and pancreatic cancer cells. Further understanding of their biological function, as well as the targets they regulate in these settings, could uncover novel pathways for therapy design.