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Tumor Discovery                                                  Drug repurposing for pancreatic cancer via AI




            Table 1. Information on candidate molecular drugs for selected pancreatic ductal adenocarcinoma biomarkers based on their
            regulatory capacity, sensitivity, and toxicity
                                                   Target biomarker : c‑MYC(+)
            Potential drug         Regulation ability (L1000)     Sensitivity (PRISM)       Toxicity (LC50, mol/kg)
            Tipranavir                  −1.33845971                 −0.283941421                  4.556
            Tolcapone                  −0.072789862                 −0.26251132                    4.78
            Gemcitabine                −0.544798394                 −2.417963872                  2.381
                                                  Target biomarker : FOXO3(+)
            Potential drug         Regulation ability (L1000)     Sensitivity (PRISM)       Toxicity (LC50, mol/kg)
            Atracurium                 −0.238786879                 −0.468347976                  5.587
            MK-2206                    −0.503738765                 0.772406631                   5.561
            ARN-509                     −0.93691652                  0.02300543                   3.673
                                                   Target biomarker : TP53(*)
            Potential drug         Regulation ability (L1000)     Sensitivity (PRISM)       Toxicity (LC50, mol/kg)
            Gemcitabine                −0.537988045                 −2.417963872                  2.381
            Guanadrel                  −0.915635131                 −0.411395434                   2.38
            Bemegride                  −3.718984186                 1.008142951                   1.532
            Notes: *Denotes the mutation; +denotes overexpression on the corresponding biomarker.
            Abbreviations: FOXO3: Forkhead box O3; LC50: Lethal concentration 50%; PRISMA: Pharmaceutical Regulatory Information System; TP53: Tumor
            suppressor p53.

                                                                                                            *
            target pairs into feature vectors to enable input into the   where  d a  represents  the  a-th  drug  feature,  and  d
                                                                                                            a
            DNN model. To generate the feature vectors, we used the   indicates the a-th drug feature after standardization; σ a and
            Protein Feature Server and PyBioMed tool in a Python   µ a refer to the standard deviation and mean of the  a-th
            3.7 environment. The drug features encompass widely   drug feature, respectively. A denotes the total number of
            utilized structural and physicochemical data, while   drug features.
            the target features are derived from the structural and
            physicochemical characteristics of proteins and peptides,   Similarly,
            determined from their amino acid sequences. Each drug-  *  t   b
                                                                   b
            target pair was combined into a single feature vector. The   t      for b = 1,2…,B−1, B  (XXXVII)
                                                                b
            feature vector for the i-th drug-target pair in DTI databases   b
            can be presented as:                                 where  t b denotes the  b-th target feature, and  t
                                                                                                            *
                                                                                                            b
                                                i
             i
                                                   D T
            q drug target    d d ,, , d A1 , dt t ,, ,, t B1 , t    ,   i i  represents the b-th target feature after standardization; σ b
                                              B

                         2
                      1
                                  A
                                      2
                                    1
                                                               and µ b refer to the standard deviation and mean of the b-th
                                                   (XXXV)      target feature, respectively; B represents the total number
              for i=1,2…,180315, A + B = 1359                  of target features.
              The total feature vector dataset consists of 180,315   Given that the DNN-based DTI model (Figure  3)
            entries,  including  80,291  experimentally  validated  DTIs   requires 996 input nodes, the total (A+B) feature vector
            and 100,024 unvalidated interactions. To address the   dimension needed to be reduced so that these drug-target
            imbalance in the dataset, we downsampled the unvalidated   feature vectors can be input to train the DNN-DTI model.
            interactions to match the number of validated entries.   By selecting the top 85% significant features for both drugs
            Before training the DNN-DTI model, we standardized   and targets using the principal component analysis (PCA),
            and transformed the drug-target interaction data because   we reduced the dimensionality of the features from 1,359
            of variations in units among the different feature vectors.   to 996. This reduction aligns with the model’s input layer
            Standardization highlights the differences between each   dimension and enhances training performance. 38
            feature vector. The standardization of the features is shown
            as follows:                                          All the aforementioned data preprocessing steps were
                                                               performed to enable the DNN-DTI model to effectively
                d
             *
            d   a   a   for a = 1,2…,A−1, A       (XXXVI)     learn from feature data of drug-target interactions. After
                   a                                          completing the data preprocessing, we split the dataset into
             a
            Volume 4 Issue 1 (2025)                         57                                doi: 10.36922/td.4709
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