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Tumor Discovery                                                  Drug repurposing for pancreatic cancer via AI




                    R w                                               S y        U y         V y
             w
                                                                y
                            n pn
                                                                                                       ln
                                                   n
                                                                           tn
                                                                                       ln
            p  n    wr   p    r    w PPIN   w PPIN    (I)  ln      ys s     yu u     yv mn
                          w
                                                                                                   v
                                                                                                        y





                    r1                                               s1        u1         v1
                                                                     n                              (III)

              for w = 1,2…,W-1,W,n = 1,2…,N-1,N                   y  y
              among which p w [n] and p r [n] denote the expression   for y = 1,2…,Y-1,Y, n = 1,2…,N-1,N
            levels of the w-th protein and the r-th protein in the n-th
            sample, respectively; π w r represents the interaction ability   where  l y [n] indicates the expression level of the  y-th
                               −
            between the r-th protein and the w-th protein; R w is the   lncRNA in the n-th sample; S y, U y, and V y represent the total
            total number of proteins interacting with the w-th protein;   numbers of TFs, lncRNAs, and miRNAs binding to the y-th
            W denotes the total number of proteins in the candidate   lncRNA, respectively; t s [n], l u [n], and m v [n] denote the
            PPIN; N is the number of data samples (PDAC or non-  expression levels of the s-th TF, the u-th lncRNA, and the
            PDAC); β w PPIN indicates the basal expression level of the   v-th miRNA in the n-th sample, respectively; ζ y s symbolizes
                                                                                                   −
                     −
            w-th protein, reflecting changes due to interactions such   the transcriptional regulatory ability of the s-th TF on the
            as  acetylation,  phosphorylation,  or  unknown  histone   y-th lncRNA;  ψ y u signifies the transcriptional regulatory
                                                                            −
            modifications that cannot be modeled in (1);  δ w PPIN [n]   ability of the  u-th lncRNA on the  y-th lncRNA;  k y v > 0
                                                                                                        −
                                                    −
            accounts for random noise affecting the w-th protein in   represents the post-transcriptional regulatory ability of the
            the n-th sample due to modeling residuals, experimental   v-th miRNA in degrading the y-th lncRNA’s miRNA; Y is the
            measurement errors, or environmental interference.  total number of lncRNAs in the candidate GWGEN; N is the
                                                               number of data samples (PDAC or non-PDAC); β y reflects
              After establishing the PPI system model, we also   the expression basal level of the y-th lncRNA, influenced
            developed a regulatory system model to describe the   by modifications such as phosphorylation, acetylation, or
            relationships between genes and their regulators, including   unknown gene regulatory effects; δ y [n] captures the random
            TFs, miRNAs, and lncRNAs. The transcriptional regulation   noise affecting the y-th lncRNA in the n-th sample due to
            system model for the x-th gene in the n-th sample can be   modeling residuals and measurement errors.
            expressed as: 28
                                                                 Finally, we established the miRNA regulatory system
                    S x        U x        V x                  model in a similar manner. The transcriptional regulation
             x
            g  n    xs s     xu u     xv mn   g  x    n  system model for the z-th miRNA in the n-th sample can
                         tn
                                    ln
                                                 v




                    s1        u1        v1
             x   x    n                          (II)    be described by the following equation:

                                                                       S z        U z        V z
                                                                 z
                                                                                       ln
                                                                           tn
                                                                                                    v
              for x = 1,2…,X-1,X, n = 1,2…,N-1,N               mn      zs s     zu u     zv mn



                                                                       s1        u1        v1
              where  g x [n] indicates the expression level of the  x-th   mn      n                  (IV)



            gene in the n-th sample; S x, U x, and V x represent the total   z  z  z
            number of TFs, lncRNAs, and miRNAs binding to the x-th   for z = 1,2…,Z-1,Z, n = 1,2…,N-1,N
            gene, respectively;  t s  [n],  l n  [n],  and  m v  [n]  denote  the   where m z [n] represents the expression level of the z-th
            expression levels of the s-th TF, the u-th lncRNA, and the   miRNA in the n-th sample; S z, U z, and V z indicate the total
            v-th miRNA in the n-th sample, respectively; α x s symbolizes   number of TFs, lncRNAs, and miRNAs binding to the z-th
                                                −
            the transcriptional regulatory ability of the s-th TF on the   miRNA, respectively; t s [n], l u [n], and m v [n] denote the
            x-th gene; γ x u signifies the transcriptional regulatory ability   expression levels of the s-th TF, the u-th lncRNA, and the
                      −
            of the u-th lncRNA on the x-th gene; εx − y > 0 indicates the   v-th miRNA in the n-th sample, respectively; λ z s symbolizes
                                                                                                   −
            post-transcriptional regulatory ability of the v-th miRNA in   the transcriptional regulatory ability of the s-th TF on the
            degrading the x-th gene’s miRNA; X is the total number of   z-th miRNA;  µ z u signifies the transcriptional regulatory
            genes in the candidate GWGEN; N is the number of data   ability of the u-th lncRNA on the z-th miRNA; ρ z v > 0
                                                                            −
            samples (PDAC or non-PDAC);  β x represents the basal   represents the post-transcriptional regulatory ability of the
                                                                                                         −
            expression level of the x-th gene, influenced by modifications   v-th miRNA in degrading the z-th miRNA’s miRNA; Z is
            such as methylation, phosphorylation, acetylation, or   the total number of miRNAs in the candidate GWGEN; N
            unknown gene regulatory effects;  δ x [n] accounts for the   is the number of data samples (PDAC or non-PDAC); β z
            random noise affecting the x-th gene in the n-th sample due   indicates the change in the expression of the z-th miRNA
            to modeling residuals and measurement errors.      due to phosphorylation, acetylation, or unknown gene
              Next, we established the regulatory system model for   regulatory effects;  δ z [n] accounts for the random noise
            lncRNA. The transcriptional regulation system model for   affecting the z-th miRNA in the n-th sample due to model
            the y-th lncRNA in the n-th sample is described as:  residuals and experimental measurement errors.
            Volume 4 Issue 1 (2025)                         51                                doi: 10.36922/td.4709
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